Monitoring Report M-1072 | 2018

Monitoring ocean acidification in Norwegian seas in 2017

MADE BY: Institute of Marine Research, Uni Research, Norwegian Institute for Water Research

COLOPHON

Executive institutions (the institutions are responsible for the content in the report) Institute of Marine Research, Uni Research, Norwegian Institute for Water Research

Project manager for the contractor Contact person in the Norwegian Environment Agency Melissa Chierici Gunnar Skotte

M-number Year Pages Contract number M-1072 2018 106 17078007

Publisher The project is funded by Norwegian Environment Agency Norwegian Environment Agency

Author(s)

Jones, E., M. Chierici, I. Skjelvan, M. Norli, K.Y. Børsheim, H.H. Lødemel, T. Kutti, K. Sørensen, A.L. King, K. Jackson, T. de Lange

Title – English and Norwegian

Monitoring ocean acidification in Norwegian seas in 2017/ Havforsuringsovervåking i norske farvann i 2017

Summary – Sammendrag

This is the annual report from 2017 based on the program: ‘Monitoring ocean acidification in Norwegian waters’ funded by the Norwegian Environment Agency. The measurements are performed by the Institute of Marine Research (IMR), Norwegian Institute for Water Research (NIVA), and Uni Research (UNI), and the measurements cover the area from Skagerrak/North Sea in the south, through the Norwegian Sea, and the seasonally sea-ice covered northern Barents Sea. IMR conducted water column measurements along repeated transects, mainly during winter in the North Sea (Torungen–Hirtshals section), in the Norwegian Sea (Svinøy-NW and Gimsøy-NW sections), in the Barents Sea (Fugløya-Bjørnøya section and stations in the NE Barents Sea), and at Skrova and Arendal coastal stations. UNI conducted water column measurements at Station M, continuous surface measurements at the same site, and water column measurements at two coastal stations in Hardanger. NIVA performed surface water measurements on two sections; Oslo-Kiel (North Sea/Skagerrak) and Tromsø-Longyearbyen (Barents Sea opening) during all of 2017. This report shows and discusses some time series and trends for the period 2011-2017.

Denne rapporten gjelder undersøkelser av havforsuring i 2017 utført av Havforskningsinstituttet (IMR), Norsk institutt for vannforskning (NIVA) og Uni Research (UNI) på oppdrag fra Miljødirektoratet. Måleområdet i rapporten går fra Skagerrak/Nordsjøen, gjennom hele Norskehavet og til nordlige deler av Barentshavet. IMR har gjort vannsøylemålinger, i hovedsak vinterstid, langs faste snitt i Nordsjøen (Torungen–Hirtshals), Norskehavet (Svinøy- NV og Gimsøy-NV), i Barentshavet (Fugløya-Bjørnøya og stasjoner i det nordøstlige Barentshavet), og ved Arendal og Skrova kyststasjon. UNI har gjort vannsøylemålinger gjennom store deler av året på Stasjon M i Norskehavet, kontinuerlige overflatemålinger på Stasjon M, og vannsøylemålinger på to kyststasjoner i Hardanger. NIVA har gjort overflatemålinger store deler av året på strekningen Oslo-Kiel og Tromsø-Longyearbyen. I denne rapporten presenteres og diskuteres tidsserier fra perioden 2011-2017.

4 Keywords 4 Emneord

Carbonate system, interannual and seasonal Karbonmålinger, mellomårlig-og sesongs-

variability, biogeochemical processes variasjon, biogeokjemiske prosesser

Cover photo Photo: Kim Abel

Tromsø, mai 2018

Authors: Elizabeth Jones*, Melissa Chierici*, Ingunn Skjelvan**, Marit Norli***, Knut Yngve Børsheim*, Helene Hodal Lødemel*, Tina Kutti*, Kai Sørensen***, Andrew Luke King***, Kristin. Jackson**, Tor de Lange**

*Havforskningsinstituttet (IMR), **Uni Research (UNI), ***Norsk institutt for vannforskning (NIVA)

This report should be cited:

Jones, E., Chierici, M., I. Skjelvan, M. Norli, K.Y. Børsheim, H.H. Lødemel, T. Kutti, K. Sørensen, A.L. King, K. Jackson og T. de Lange. 2018. Monitoring of ocean acidification in Norwegian seas in 2017, Rapport, Miljødirektoratet, M-XXX|2018 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Content

Content ...... 4 Summary ...... 5 Extended Norwegian Summary ...... 8 1. Introduction ...... 11 2. Methods and Data...... 13 2.1 Sampling and Variables ...... 16 2.2 Measurements of Total Alkalinity and Total Inorganic Carbon ...... 17 2.3 pH Measurements...... 17

2.4 pCO2 Measurements ...... 18 2.5 Calculation of pH and Saturation State of Calcite and Aragonite ...... 18 3. Results ...... 19 3.1 North Sea and Skagerrak ...... 19 3.1.1 Spatial variability along Torungen-Hirtshals section ...... 19 3.1.2 Seasonal variability at Arendal station ...... 22 3.1.3 Seasonal variability in surface water ...... 24 3.1.4 Trend analysis at selected stations ...... 28 3.2 Norwegian Sea ...... 31 3.2.1 Spatial variability along the Svinøy-NW section ...... 31 3.2.2 Spatial variability along the Gimsøy-NW section ...... 34 3.2.3 Seasonal variability in open ocean ...... 36 3.2.4 Seasonal variability in coastal water ...... 41 3.2.5 Trend analysis at selected stations ...... 45 3.3 Barents Sea ...... 52 3.3.1 Spatial variability along the Fugløya-Bjørnøya section ...... 52 3.3.2 Spatial variability along the northeastern Barents Sea section ...... 55 3.3.3 Seasonal variability in surface water ...... 56 3.3.4 Trend analysis at selected stations ...... 60 3.4 Norwegian Coast ...... 66 3.5 Cold Water Coral Reefs ...... 67 4. Summary and Recommendations ...... 69 5. References ...... 71 6. Attachments ...... 74 6.1 Plots ...... 74 6.2 Data Tables ...... 81 6.3 Definitions ...... 104

4 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Summary This is the annual report from 2017 based on the program: ‘Monitoring ocean acidification in Norwegian waters’, which began in 2013 and is funded by the Norwegian Environment Agency.

The report is based on measurements of AT, CT, pCO2 and pH made by the Institute of Marine Research (IMR), Norwegian Institute for Water Research (NIVA) and Uni Research (UNI) with updated data from 2017. IMR conducted water column measurements along repeated transects during winter and spring 2017 in the North Sea (Torungen–Hirtshals), at two sections in the Norwegian Sea (Svinøy-NW and Gimsøy-NW), and at two sections in the Barents Sea (Fugløya-Bjørnøya in February and April 2017, and in the northeastern Barents Sea in September 2017). The Norwegian Sea water column was also investigated by UNI which performed seasonal studies at Station M. Moreover, UNI also contributed with continuous surface pCO2 data at Station M. NIVA performed seasonal cruises (winter, spring, summer and autumn) for surface water measurements on two sections; Oslo-Kiel (North Sea) and Tromsø- Longyearbyen (Barents Sea opening) during 2017, and present data on both seasonal and interannual basis. In addition, the report includes data from monthly measurements at a coastal site in Skrova in Lofoten and Arendal in Skagerrak (IMR) and from two coastal sites in Hardanger (UNI). All sampling positions are shown in Figure 1.

This report includes carbonate chemistry data and ancillary variables such as salinity, temperature, and inorganic nutrient concentrations to provide baseline observations of variability attributed to oceanographic and anthropogenic processes such as the influence of mixing of water masses, freshwater/meltwater inputs, CO2 emissions and oceanic uptake, and biological processes including production and respiration. For water column data, this is measured each year and the observed seasonal and interannual variability is largely derived from changes in the Atlantic water inflow, and the extent and mixing of fresher coastal and polar waters. The data also provides information that can be used in projections of future CO2 emission scenarios and estimates in changes in the depth of the calcium carbonate (CaCO3) saturation horizon. However, to determine the individual drivers of ocean acidification and their regional, seasonal and interannual variability requires integrated monitoring including measurements or proxies for biological productivity, ocean physics, and land-ocean exchanges, in both surface water and in the water column.

North Sea Winter data from the water column in the North Sea along the Torungen-Hirtshals section and monthly sampling at the coastal station Arendal was carried out in the Skagerrak region.

Variability in the CO2 system in this region is primarily driven by changes in salinity resulting from the balance of freshwater inputs from riverine and Baltic sources with salty waters from the Atlantic Ocean. The Norwegian coastal station was characterised by relatively colder and fresher surface waters, in contrast to the core of Atlantic water with higher temperature ( 7.5°C) at 50-250 m depth (Figure 1, Appendix 6.1). Deepest parts of the water column (600 -1 m) were occupied by the cold, older water mass with AT values around 2340 μmol kg and CT -1 -1 of 2207 μmol kg . The Atlantic water had CT in the range 2160-2170 μmol kg , consistent with previous data from the region. The upper ocean was characterised by lower AT (less than 2250 -1 -1 μmol kg ) and lower CT (less than 2120 μmol kg ) as a result of influences of the fresh coastal current and biological activity. High pH and aragonite saturation occurred in the upper 50 m, which decreased with depth to lower pH values within the Atlantic water. Lowest pH and aragonite saturation states were found at 600 m depth in the deepest parts of the section

5 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 towards the Danish coast. At the deepest (600 m) part of the region, temperatures increased by 0.31C yr-1 since 2010, which was accompanied by a general increase in salinity, indicating greater incursions of warm and saline water masses into the Skagerrak region (Figure 14). This impacted pH and aragonite saturation, where a reduction in pH of 0.013 per year was detected.

The underway measurements made by NIVA in 2017 from M/S Color Fantasy between Oslo and Kiel also show the seasonal variations and fresh water impacts in Skagerrak (Figures 9-10). The average salinity during winter was 29.56 and 24.75 during summer. The temperature was on average 16.91 C in summer and 3.48 C in the winter. pH showed very small seasonal variation in 2017, likely from not having phytoplankton blooms during any of the cruises in the summer. In winter the pH average was 8.07 while it was 8.02 in the summer. The ΩAr was lower during winter and spring, on average 1.49 during spring and 2,11 during autumn. In the Oslofjord ΩAr was < 1 during autumn.

Norwegian Sea Data from the Norwegian Sea were collected annually from two sections Svinøy-NW (Figure 18) and Gimsøy-NW (Figure 20) and monthly from fixed station Station M (Figures 21 to 26) and coastal station Skrova (Figures 29 to 32). The Norwegian coastal current affected the near shore stations at Svinøy-NW and Gimsøy-NW with a relatively colder and fresher surface layer. Warm and salty Atlantic water was present until about 400 m depth, overlying the Arctic water mass.

The distribution of AT and CT show reduced values towards the coast typical of the Norwegian -1 coastal current. Values of AT around 2315-2325 μmol kg characterise the core of Atlantic water, compared to the fresher Arctic water below. Seasonal biological activity leaves an imprint on upper ocean CT with low values remaining into the winter. pH showed similar values of about 8.04-8.05 in the upper waters of most of the whole section. Patches of low pH ~8.02 water occurred around 500 m depth in the central part of the section and at the deepest point, furthest offshore. The saturation state for aragonite varied from highest values in the upper 400 m of the water column with a decreasing vertical gradient to reach the saturation horizon at around 2000 m depth offshore. Waters below 2000 m were undersaturated (ΩAr < 1.0) with lowest values of 0.91. Figure 37 shows the aragonite saturation state at different depths along the Svinøy-NW section at 1ºE from 2011 to 2017. The data show interannual variability related to the variations in the presence of cold and fresh Arctic water, with greater variability at 1000 m depth, perhaps due to interactions between the Arctic water and warmer Atlantic water mass. The aragonite saturation state at 1500 m had been decreasing year to year, but since 2016 values slightly increased again. A similar trend was detected at 1500 m depth along the Gimsøy-NW section at 12.3 E (Figure 39).

Measurements from Station M (Figures 21 to 26) show seasonal variability for 2017 as for the previous years, with decrease in CT in the upper water layer in late April/early May due to spring blooming. Seasonal variations are greatest in the surface water and are less pronounced at depth. pH and aragonite saturation in the surface water are also affected by biological activity, and instances of low pH and  at depth were likely due to CO2 produced from respiration of accumulated remineralized material. In the surface water the aragonite saturation increased from 1,86 to 2,57 from winter to summer of 2017, which is an amplitude comparable to previous years. The saturation horizon with respect to aragonite is seen at approximately 2000 m, which is deeper compared to earlier years, illustrating the variability of the system. When comparing the years 2011 to 2017 at Station M we see that the deep-

6 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

water pH is decreasing with 0.0034 units each year, while the Ar is decreasing by 0.0075 units per year. These trends are slightly less than those from 2011-2016 (Chierici et al., 2017), but still larger than those from Skjelvan et al. (2014), which was based on a larger area.

Monthly measurements from Hardanger (Figure 27) at the west coast show strong seasonal signals in the upper 50-100 m. The aragonite saturation is at highest (2.1-2.2) in the surface during summer coinciding with the warmest water (16°C), while pH has its surface maximum (8.12) a couple of months earlier, in June. Mixing of water masses seems to have higher influence of the narrow Langenuen station than that in the open Hardangerfjord. Undersaturation with respect to aragonite is not seen during the months of measurements. The time series in Hardanger is too short to see significant trends. However, trends from a station north of Hardanger – Korsfjorden – are significant negative for both pH (-0.007) and aragonite saturation (-0.02), Figure 35.

Monthly measurements at coastal station Skrova in Vestfjorden (Figures 29 to 32) show strong seasonal signals in the upper 100 m, with warming up to 14 C and freshening during the summer. By early summer, pH increases in the upper 50 m, likely due to a combination of freshwater inputs (reductions in salinity) and CO2 uptake during the spring bloom period. Aragonite saturation state varies with water masses, primary production and input of ice melt water, and is supersaturated throughout the year in the whole water column.

The Barents Sea Sampling was carried out along the Fugløya-Bjørnøya section in the Barents Sea opening in southwestern Barents Sea and along the Vardø-N transect in eastern Barents Sea (Figures 43- 44). The latter transect is sampled in conjunction with the IMR-PINRO Barents Sea ecosystem surveys ‘ØKOTOKT’.

Coastal waters near Fugløya are influenced by the fresh Norwegian coastal current and deepest levels are occupied by Atlantic water with salinity >35.1 and temperature ~6°C (Figure 4, Appendix 6.1). Near Bjørnøya the inflow of polar waters travelling south from north east Svalbard creates strong horizontal gradients at the polar front at around 73.5°N, leading to reduced salinity and temperatures in the upper 100 m at the northern limit of the section. The distribution of AT acts as an indicator tracer of the key water masses of the

Barents Sea; coastal water, Atlantic water and Arctic water. Atlantic water has AT around 2325-2330 μmol kg-1 where strong decreasing gradients to lowest values around 2290 μmol kg-1 are indicative of polar water. The distribution of CT showed a slightly different pattern, from values of 2146-2150 μmol kg-1 in the upper 200 m to lowest values in the north. High pH (>8.15) occurred at the northern end of the section with lowest values 8.04-8.05 overlying the seafloor at 73.5°N (Figure 43). The saturation state for aragonite had a general decreasing gradient in the water column, with lowest values around 1.6 below 300 m depth at 73.5°N. This was a similar trend in the northeastern Barents Sea (Figure 5, Appendix 6.1), with higher pH values and elevated saturation states in the upper 100 m in the north (Figure 44).

Temperature and CT concentrations at 300-400 m depth at the 72.8ºN along the Fugløya- -1 -1 Bjørnøya section showed a warming trend of 0.31 C yr and decrease in CT of -1.9 µmol kg yr-1 (Figure 51). This yielded an increase in both pH and Ω aragonite of 0.009 yr-1 and 0.06 yr- 1, respectively, following a similar pattern to surface waters of the Barents Sea opening (Figure 49).

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Carbonate chemistry from surface waters was measured throughout 2017 by NIVA in the Barents Sea Opening between Tromsø, Norway and Longyearbyen, Svalbard (Figures 46-47). Freshwater input, biological production during summer, and circulation likely played important roles in the observed variability. The salinity for the stations in the open sea sections of the transect (both South and North of the Bjørnøya was on average lowest at 34.71 in the summer and highest at 35.02 in the winter. The temperature was as low as 3.88 C in the winter and as high as 10.19 C on average for stations in the open sea section North of Bear island, while south of the bear island the average was 6.22 C in the winter and 10.38 C in the summer. The pH was lowest at 8.06 in the winter and highest at 8.14 in summer on average for the stations both in the North and South open sea sections. The aragonite saturation was as low as 1.66 in winter and as high as 2.50 on average for stations in the northern open sea section and 1.82 in winter and 2.54 in summer in the southern open sea section. For the stations closer to the coast of Norway the average salinity was lowest at 34.01 in summer and 34.45 in winter, temperature was 11.15 C in summer and 5.95 C in winter, pH was 8.12 in summer and 8.06 in winter and aragonite saturation was 2.46 in summer and 1.79 in winter. For the stations closer to the coast of Svalbard the average salinity was lowest at 33.89 in summer and as high as 34.90 in winter, the temperature was 8.55 C in summer and 4.01 C in the spring (lower than winter), pH was highest at 8.20 in spring and lowest at 8.05 in winter and aragonite saturation was 2.39 in summer and lowest at 1.79 in the autumn.

Extended Norwegian Summary Denne rapporten omhandler havforsuring av norske farvann i 2017 og arbeidet er gjort av Havforskningsinstituttet (IMR), Norsk institutt for vannforskning (NIVA) og Uni Research (UNI) på oppdrag fra Miljødirektoratet innenfor programmet ‘Havforsuringsovervåking i norske farvann’, som startet i 2013. Rapporten er basert på diskrete målinger av total alkalinitet

(AT), totalt uorganisk karbon (CT) og pH, samt kontinuerlige målinger av pCO2 og pH. Både overflaten og vannsøylen er målt og målefrekvens, parameter og dyp er beskrevet i Tabell 1. IMR har samlet inn vannsøyleprøver fra faste snitt i Nordsjøen (Torungen–Hirtshals), i Norskehavet (Svinøy-NV og Gimsøy-NV), i Barentshavet (Fugløya-Bjørnøya og stasjoner i det nordøstlige Barentshavet), og fra kyststasjonene Arendal og Skrova. Norskehavet er også undersøkt av UNI, som har samlet prøver fra vannsøylen på Stasjon M og gjort kontinuerlige overflatemålinger fra samme posisjon. I tillegg har UNI tatt vannsøyleprøver fra to kyststasjoner i Hardanger. NIVA har gjort overflatemålinger i vestlige deler av Barentshavet (Tromsø-Longyearbyen) og Skagerrak samt deler av Oslofjorden (Oslo-Kiel). Alle målepunkt er vist i Figur 1.

Rapporten inkluderer karbonatsystemdata (AT, CT, pH, pCO2) og tilleggsdata som salt, temperatur og næringssalt. Karbonatsystemet påvirkes av ulike prosesser som blanding av vannmasser (f.eks. atlantisk vann, kystvann, smeltevann), biologisk produksjon, respirasjon og opptak av atmosfærisk CO2. Det er viktig å få kunnskap om den naturlige variabiliteten i systemet for å detektere små menneskeskapte endringer, og målingene i programmet komplementerer hverandre i så henseende. Vannkolonnemålingene som tas årlig og gir over tid informasjon om mellomårlige variasjoner og trender i karbonatsystemet. Vannkolonnemålingene som tas hver/annenhvermåned gir grunnleggende kunnskap om sesongvariasjonen til systemet, og kontinuerlige overflatemålinger gir oss en god prosessforståelse. Rapporten presenterer målinger gjort i 2017, men her diskuteres også målinger fra tidligere år og hvordan trender i de ulike havområdene utvikler seg.

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De dominerende vannmassene i det norske havområdet er kyststrømmen, Atlanterhavsvann og polarvann, og en stor del av den observerte variasjonen mellom sesonger og fra år til år er drevet av endringer i det innstrømmende atlantiske vannet og av blanding med ferskt kystvann, polarvann eller smeltevann. For å få full oversikt over enkeltfaktorene bak havforsuring, regional variabilitet og sesong- og mellomårlige endringer trengs en bred overvåkning som inkluderer målinger/estimat for biologisk produksjon, havfysikk i overflate og dyp og utveksling mellom land og hav, og ikke minst trengs langsiktighet i overvåkningen.

Nordsjøen Fra Nordsjøen finnes i 2017 vinterdata fra hele vanndypet langs snittet Torungen-Hirtshals og i Skagerrak er det tatt månedlige prøver fra kyststasjonen ved Arendal (IMR) og overflateprøver mellom Oslo og Kiel (NIVA). I denne regionen er variabiliteten i CO2-systemet hovedsakelig drevet av endringer i saltinnhold. Saltinnholdet er bestemt av innstrømmende ferskvann fra elver og fra Østersjøen og saltere vann fra Atlanterhavet. Stasjonen ved Arendal hadde relativet kaldt og ferskt overflatevann som kontrast til den varme kjernen av atlanterhavsvann ( 7.5°C) ved 50-250 m (Figur 1, Vedlegg 6.1). På dypet (600 m) var det -1 -1 kaldt og gammelt vann med AT rundt 2340 μmol kg og CT på 2207 μmol kg . Det atlantiske -1 vannet hadde CT–konsentrasjoner på 2160-2170 μmol kg som også er observert tidligere fra -1 - dette området. Øvre vannlag hadde lavere AT (< 2250 μmol kg ) og lavere CT (< 2120 μmol kg 1) som et resultat av innblanding av den ferske kyststrømmen og biologisk aktivitet. I de øvre 50 m var pH og aragonittmetningen høy, men verdiene avtok nedover i dypet når andelen av atlantisk vann ble høyere. Lavest pH og aragonittmetning ble observert på 600 m dyp ved den dypeste delen av snittet mot danskekysten. Her har temperaturen økt med 0,31C år-1 siden 2010 og saltinnholdet har også økt, som indikerer at mer varmt og salt vann har strømmet inn i Skagerak (Figur 14). Dette har påvirket pH og aragonittmetningen, og pH har avtatt med 0,013 per år de siste årene.

Underveismålinger av overflatevann mellom Oslo og Kiel (M/S Color Fantasy; NIVA) viser sesongvariasjoner i området og innstrømming av ferskvann påvirker karboninnholdet i Skagerrak (Figur 9-10). Midlere saltinnhold om vinteren var 29,56 og 24.75 om sommeren. Middeltemperatur var 16,91 C om sommeren og 3,48 C om vinteren. Sesongvariasjonen var liten i pH i 2017 og dette har sammenheng med at det heller ikke ble observert oppblomstring i løpet av sommermålingene. Om vinteren var midlere pH 8,07 mens sommerverdien var 8,02. Metningskonsentrasjonen av aragonitt var lavere om vinteren og våren (midlere vårverdi 1,49 og høstverdi 2,11). I Oslofjorden var aragonittmetningen < 1 om høsten.

Norskehavet Fra Norskehavet finnes det i 2017 vinter- og vårdata fra hele vanndypet langs to snitt - Svinøy- NV (Figur 18) og Gimsøy-NV (Figur 20) - og månedlige data fra Skrova kyststasjon (Figur 29- 32) (IMR). I tillegg finnes data fra ca. hver annen måned fra hele vanndypet ved Stasjon M (Figur 21-26), kontinuerlige overflatedata fra samme sted, og månedlige prøver fra to kyststasjoner i Hardanger mellom juni og november (Figur 27) (UNI). Den norske kyststrømmen påvirket de kystnære stasjonene på snittene Svinøy-NV og Gimsøy-NV der relativt kaldt og ferskt vann ble observert i overflata. Vest for kyststrømmen strømmet varmt og salt atlantisk vann i de øverste 400 m og dypere fantes vann med arktisk opprinnelse.

AT og CT avtar mot kysten og kyststrømmen. I kjernen av det atlantiske vannet var AT omkring 2315-2325 μmol kg-1 som var høyere enn i det arktiske vannet på større dyp. Biologisk aktivitet om vår og sommer satte sitt preg på vannet i de øverste lagene med lave CT–verdier langt utover høsten. pH var relativ stabil på 8,04-8,05 i øverste vannlag langs hele Svinøy-NV, mens den varierte noe mer langs Gimsøy-NV. Områder med lav pH (~8,02) ble observert på

9 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 ca. 2500 m dyp lengst borte fra kysten på Svinøy-NV. Aragonittmetningen varierte mellom høye verdier i de øverste 400 m til lavere verdier nedover i vannkolonna. Metningshorisonten for aragonitt ble observert på omkring 2000 m dyp, og vann dypere enn dette var undermettet med aragonitt (ΩAr < 1.0). Laveste aragonittmetning var 0,91. Figur 37 viser trender i aragonittmetningen på ulike dyp ved Svinøy-NV. Data er fra stasjonen 1ºE og tidsperioden er fra 2011 til 2017. Observerte mellomårlige variasjoner kan knyttes til innblanding av varierende mengde kaldt og ferskt arktisk vann langs Svinøy-NV, og størst variasjon ses på 1000 m dyp. Aragonittmetning ved 1500 m dyp har avtatt over årene, men siden 2016 ses en liten økning. En tilsvarende trend kunne ses på Gimsøy-NV-stasjonen på 12,3E (Figur 39).

Målinger fra Stasjon M (Figur 21-26) viste sesongvariabilitet i 2017 som også er observer tidligere år, men med litt endret start for oppblomstringen. CT avtok i de øvre vannlag i månedsskiftet april/mai på grunn av biologisk aktivitet, og sesongvariasjonene var større i de øverste vannlag enn på større dyp. pH og aragonittmetning i overflatevannet var også påvirket av biologi, og lav pH og aragonittmetning på midlere dyp var trolig et resultat av CO2 produsert fra respirasjon av akkumulert remineralisert materiale. I overflatevann økte aragonittmetningen fra 1,86 til 2,57 fra vinter til sommer 2017, og dette er en sesongsvingning som er sammenlignbar med tidligere år. Metningshorisonten for aragonitt ble observert omkring 2000 m dyp som er noe dypere enn tidligere år. Dette illustrerer variabiliteten i systemet. Trender over årene 2011 til 2017 fra Stasjon M viser at pH i dypvannet avtar med 0,0034 enheter pr år mens aragonittmetningen avtar med 0,0075 enheter pr år. Disse trendene er noe svakere enn de fra 2016-rapporten (Chierici et al., 2017), men de er fremdeles sterkere enn trendene estimert i Skjelvan et al. (2014), der et større område ble undersøkt.

Målinger fra kyststasjoner i Hardanger (Figur 27) på vestkysten hadde markerte sesongsignal i de øverste 50-100 m. Aragonittmetningen var høyest (2,1-2,2) i overflata om sommeren samtidig som temperaturen var høyest (16°C), mens pH var høyest (8,12) i overflata et par måneder tidligere, i juni. Blanding av vannmasser så ut til å ha større betydning i det smale stredet Langenuen enn på den mer åpne stasjonen Hardangerfjord. Undermetning av aragonitt ble ikke observert på noen steder i vannmassen i løpet av månedene det ble tatt målinger. Tidsseriene i Hardanger er for korte til å se signifikante trender, men trender fra en kyststasjon litt lenger nord – Korsfjorden – er signifikant negative for både pH (-0,007) og aragonittmetning (-0,02), Figur 35.

Målinger fra Skrova kyststasjon i Vestfjorden (Figur 29-32) viste sterk sesongvariasjon i de øverste 100 m med oppvarming til 14C og ferskere vann om sommeren. pH økte i de øverste 50 m tidlig på sommeren og dette var trolig en kombinasjon av ferskvannsinnstrømming (som reduserer saltholdigheten) og CO2–opptak i våroppblomstringen. Aragonittmetningen varierte med vannmasse, primærproduksjon og tilførsel av smeltevann. Hele vannkolonnen er overmettet med aragonitt gjennom hele året.

Barentshavet Fra Barentshavet finnes det i 2017 målinger fra vannkolonna langs snittet Fugløya-Bjørnøya i Barentshavsåpningen og langs snittet Vardø-N nordøst i Barentshavet, Figur 43-44 (IMR). I tillegg har NIVA samlet inn overflatemålinger mellom Tromsø og Longyearbyen (Figur 46-47).

Vann nær Fugløya er influert av den ferske kyststrømmen og på større dyp finner man atlantisk vann med saltinnhold >35,1 og temperatur ~6°C (Figur 4, Vedlegg 6.1). Polarvann strømmer sørover fra østsiden av Svalbard og når Bjørnøya der det skapes sterke horisontale

10 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 gradienter ved polarfronten ved ca. 73,5°N, og dette fører til lavere saltholdighet og kaldere vann i de øverste 100 m av den nordligste delen av Fugløya-Bjørnøya-snittet. Fordelingen av

AT fungerer som en indikator for de viktigste vannmassene i Barentshavet; kystvann, atlantisk -1 vann og arktisk vann. Atlantisk vann har AT på 2325-2330 μmol kg mens sterkt avtakende -1 verdier ned til ca. 2290 μmol kg indikerer polart vann. Fordelingen av CT viste et annet mønster fra verdier på 2146-2150 μmol kg-1 i de øverste 200 m til de laveste verdiene i nord. Høy pH (>8.15) ble observert langs nordligste del av snittet mens laveste verdier på 8,04-8,05 ble observert ved bunnen på 73,5°N (Figur 43). Aragonittmetningen avtok gradvis nedover i vannkolonnen med laveste verdi rundt 1,6 dypere enn 300 m ved 73.5°N. Dette var tilsvarende det som ble observert i nordøstlige Barentshav (Figur 5, Vedlegg 6.1), med høy pH og økte metningskonsentrasjoner i de øverste 100 m i nordlige del av snittet (Figur 44).

Trender i temperatur og CT på 300-400 m dyp ved 72.8ºN (Fugløya-Bjørnøya) viste en -1 -1 -1 oppvarming på 0,31C år og reduksjon i CT på -1,9 µmol kg år (Figur 51). Dette førte til en økning i både pH og aragonittmetning på henholdsvis 0,009 år-1 og 0,06 år-1. Dette tilsvarer det som ble observert i Barentshavåpningen (Figur 49).

Underveismålinger av overflatevann mellom Tromsø og Longyearbyen, Figur 46-47 (M/S Norbjørn; NIVA) viser at innstrømming av ferskvann, biologisk produksjon og sirkulasjon er alle viktige drivere for den observerte variabiliteten i karbonsystemet. Saltinnholdet i åpent vann nord og sør for Bjørnøya var lavest om sommeren (34,71) og høyest om vinteren (35,02). Nord for Bjørnøya var vintertemperaturen lav (3,88 °C) og sommertemperaturen relativ høy (10,19 °C), mens sør for Bjørnøya var vintertemperaturen 6,22 °C og sommertemperaturen 10,38 °C. pH-verdien var lavest (8,06) om vinteren og høyest (8,14) om sommeren i åpent vann både sør og nord for Bjørnøya. Aragonittmetningen var lav (1,66) om vinteren og høy (2,50) om sommeren nord for Bjørnøya, mens sør for Bjørnøya var tilsvarende verdier 1,82 om vinteren og 2,54 om sommeren. Nærmere norskekysten var midlere saltinnhold lavest (34,01) om sommeren og høyere (34,45) om vinteren, sommertemperaturen var 11,15 °C og vintertemperaturen 5,95 °C, sommer-pH var 8,12 og vinter-pH var 8,06, og aragonittmetningen om sommer og vinter var henholdsvis 2,46 og 1,79. I nord, nær kysten av Svalbard var midlere saltinnhold lavest (33,89) om sommeren og høyest (34,90) om vinteren, temperaturen var 8,55 °C om sommeren og 4,01 °C om våren (lavere enn om vinteren), pH var høy (8,20) om våren og lav (8,05) om vinteren, mens aragonittmetningen var 2,39 om sommeren og lavest (1,79) om høsten.

1. Introduction

In 2013 a separate marine acidification program was established by the Norwegian Environment Agency. The background for such an initiative is based on the fact that the global oceans currently absorb about 25% of the annual anthropogenic carbon dioxide (CO2) emissions from combustion of fossil fuels and deforestation (e.g., Takahashi et al., 2009; Le

Quéré et al., 2016; 2018). Oceanic uptake of CO2 affects the entire inorganic carbon system of the ocean, with a subsequent reduction in seawater pH and the saturation state of calcium carbonate minerals, e.g. the biomineral aragonite. Ocean acidification is occurring at a higher rate than ever in the last 55 million years. It is expected that the ocean acidification will affect the structure and function of marine ecosystems, and thus also have significant consequences for harvestable marine resources. Therefore, it is important that the agency keeps an eye on the degree of ocean acidification. The northernmost Norwegian seas have a naturally high content of inorganic carbon, and in addition the low seawater temperatures lead to higher CO2 solubility. As a result, the content of carbonates in polar waters is low

11 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 compared to more southern areas, and we expect the higher latitude seas will be the first regions to experience lower levels of seawater carbonates as a result of ocean acidification. For example, the Arctic Ocean will become undersaturated with respect to calcium carbonate during this century if CO2 emissions continue as they are today (AMAP 2013; Steinacher et al., 2009).

The ocean carbonate system is a very important part of the global carbon cycle. About 90% of - the inorganic carbon in the ocean is in the form of hydrogen carbonate (HCO3 ), 9% is in the 2- form of carbonate (CO3 ) and about 1% exists as dissolved CO2. When CO2 from the air is absorbed by the sea, the gas will become dissolved in seawater and carbonic acid (H2CO3) formed. This also causes hydrogen ions (H+) to form. Carbonic acid is rapidly transformed into hydrogen carbonate and carbonate ions, which are naturally present in the seawater and form the so-called carbonate system (Eq.1).

+ - + 2- CO2+ H2OH2CO3  H +HCO3  H + CO3 (1)

Overall, oceanic uptake of CO2 leads to an increased concentration of hydrogen ions and lower availability of carbonate minerals in seawater. This results in a decrease in the pH of the seawater, which is why the process has been called ocean acidification. The pH of the ocean is generally around 8, but the natural variations are large and are influenced by, for example, temperature, primary production, respiration and physical processes like water mass mixing. It is worth noting that the ocean will not become acidic (pH lower than 7) but rather it will become less basic. In the marine environment, it is the reduction of available carbonates that creates the most concern. Carbonate forms an important building block for many marine organisms, primarily for those with calcium scales, and calcium carbonate is formed only biologically (Eq. 2) while the solution is chemical (Eq. 3).

2+ - Ca + 2HCO3  CaCO3(s) + H2CO3 (2)

2+ 2- CaCO3(s)  Ca +CO3 (3)

Organisms with chalk shells and skeletons will have reduced ability to survive when carbonate concentration is reduced as a result of carbon uptake. According to Talmange and Gobler (2009), Andersen et al. (2013) and Agnalt et al. (2013), ocean acidification can weaken a number of economically important shellfish species, and Mortensen et al. (2001), Turley et al. (2007) and Järnegren and Kutti (2014) show that this could also be the case for the large deposits of cold water corals that are found along the Norwegian coast. When large quantities 2- of CO2 are absorbed, the concentration of carbonate ions (CO3 ) in seawater is reduced, and then calcium carbonate (CaCO3) is likely to dissolve and the shells of some organisms becomes chemically unstable (Orr et al., 2005). It has also been found that non-calcareous organisms can be adversely affected by changes in CO2 or low pH. Further, there are also organisms that respond positively to high CO2 content and low pH (Dupont and Pörtner, 2013). It is therefore difficult to predict which organisms will be the most effected to changes in ocean chemistry and pH, and thus, it is very important to study the natural variations of the ocean carbonate system in order monitor the development of the levels of carbonate concentration and so-

12 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 called saturation of the two most common types of calcium carbonate in the ocean; aragonite and calcite.

2. Methods and Data

The aim of the Ocean Acidification (OA) monitoring program is to get an overview of the status and development of OA in Norwegian waters. In addition, the program will facilitate future monitoring of the effects of OA. Most of the data is available in international databases like CDIAC and SOCAT (http://cdiac.ornl.gov/oceans/CARINA/, www.socat.info). The data are also published in the database “Vannmiljø” (vannmiljo.miljodirektoratet.no) of the Norwegian Environment Agency as well as in Norwegian Marine Data Centre (NMDC).

In 2017, a collaboration between the OA monitoring program and the Ecosystem Monitoring in Coastal Water (ØKOKYST) program was initiated, based on a need of increasing the climate relevance of the latter program. ØKOKYST aims to monitor the environmental status of selected areas along the Norwegian coast. This collaboration included monthly sample collection of nutrients (ammonia, phosphate, nitrate, silicate, total nitrogen and total phosphorous), chlorophyll-a concentration, and dissolved organic carbon on 10 stations using FerryBox on M/S Trollfjord and M/S Color Fantasy. This monitoring also included continuous FerryBox data for temperature, salinity and chlorophyll-a fluorescence among others. The reporting, however, has been done separately in the ØKOKYST reports, and will not be repeated in this report, but some chlorophyll-a fluorescence data has been used to discuss the seasonal variation in carbonate chemistry.

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Table 1 A summary of transects and cruises where sampling was performed in 2017. Section/station Sampling month Depth Parameters Institution Financing (sample type)

Torungen- January Water AT, CT IMR Environment Hirtshals column Agency (discrete)

Svinøy-NW February, May Water AT, CT IMR Environment (discrete) column Agency

Gimsøy-NW April, June Water AT, CT IMR Environment (discrete) column Agency

Fugløya-Bjørnøya February, April Water AT, CT IMR Environment (discrete) column Agency

NE Barentshav September Water AT, CT IMR Environment (discrete) column Agency/ FRAM

Tromsø-Longyear- March, May, Surface AT,CT, pH, NIVA Environment byen/Ny-Ålesund August, November Agency/ (discrete) FRAM

Oslo-Kiel January, May, Surface AT,CT, pH, NIVA Environment (discrete) July, November Agency

Station M February, April, Water AT, CT UNI Environment (discrete) June, August, column Agency /NFR/EU November

Coastal station January – Water AT, CT IMR Environment Skrova December column Agency (discrete)

Coastal station January – Water AT, CT IMR Environment Arendal November column Agency (discrete)

Station M January-June and Surface, pCO2, pH UNI Environment (continuous) November- subsurface Agency December

Coastal stations April - September Water AT, CT UNI Environment Hardanger column Agency (discrete)

Cold water coral August Water AT, CT IMR Environment reefs (discrete) column Agency

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Figure 1. Map showing positions for collected data in the programs Ocean Acidification Monitoring and Økokyst 2017. Red dots show transects were IMR sampled the water column; TH=Torungen-Hirtshals, SØ=Svinøy-NW, GØ=Gimsøy-NW, FB=Fugløya-Bjørnøya, NB=stations in the northeast Barents Sea. Red dots with black outline show the IMR coastal stations Arendal in the south and the Skrova in the north. Green dots are stations where NIVA has collected surface samples; OK=Oslo-Kiel, TL=Tromsø-Longyearbyen.

Green-blue line along the coast indicate NIVA’s Trollfjord transect for pCO2 implementation, and green dots with black outline show NIVA’s Økokyst stations, not inluded in this report. Blue dots indicate where UNI has sampled the water column; M=Station M, H=Hardanger coastal station.

Figur 1. Kart over stasjoner som har inngått i programmene Havforsuringsovervåkningen og Økokyst i 2017. Røde prikker viser snitt der IMR har tatt prøver fra hele vanndypet; TH=Torungen-Hirtshals, SØ=Svinøy-NV, GØ=Gimsøy-NV, FB=Fugløya-Bjørnøya, NB=stasjoner i nordøstlige Barentshav. Røde prikker med svart kant viser IMR sine kyststasjoner; Arendal i sør og Skrova i nord. Grønne prikker viser NIVA sine overflatestasjoner; OK=Oslo-Kiel, TL=Tromsø-Longyearbyen. Grøn-blå linje langs kysten viser NIVAs

Trollfjord-linje der pCO2 har blitt implementert, og grønne prikker med svart kant er NIIVAs Økokyst- stasjoner, som ikke er inkludert i denne rapporten. Blå prikker viser hvor UNI har tatt prøver fra hele vanndypet; M=Stasjon M, H=Hardanger kyststasjoner.

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Positions for fixed sections, transects and fixed stations that are part of the measurement program in 2017 are shown in Figure 1. The Institute of Marine Research (IMR) has conducted regular sections in the North Sea (Torungen-Hirtshals), the Norwegian Sea (Svinøy-NW, Gimsøy-NW), and in the Barents Sea (Fugløya-Bjørnøya and in the northeastern Barents Sea). In addition, monthly sampling was carried out at Arendal coastal station and also Skrova Coast Station, which is a collaboration with the ØKOKYST program (Environment Agency). In 2017, Uni Research (UNI) conducted measurements at Station M. NIVA has measured transects in the Barents Sea opening (Longyearbyen-Tromsø) and in Skagerrak (Oslo-Kiel). The Environment Agency financed additional sampling on cold water coral sites in August 2017 (Hesteneset, Straumsneset, Huglhammaren, Hornaneset in Hardanger, Hordaland), carried out by IMR. Monthly sampling from June to November at two Hardanger sites (Hardangerfjord and Langenuen) was carried out by UNI.

The Environment Agency has financed the sampling activities presented in this report but the participants in the program have also contributed data and expertise from other projects. UNI's data is collected with contributions from the EU project FixO3. NIVA's activities related to ocean acidification (OA-SIS) have been used in the work and cover costs related to method development on analyses and continuous measurements of pH and pCO2. Framsenter Flag Ship for Ocean Acidification funded parts of the Barents Sea Opening cruises on Norbjørn. From IMR, there are two projects in the Flag Ship for "Ocean acidification and ecosystem effects in Norwegian waters" at Framsenter and IMR's ecosystem surveys program that provides expertise, infrastructure and data for this report.

2.1 Sampling and Variables This project uses internationally recognized methods and procedures for water sampling and instrumentation, as described in Dickson et al. (2007); Guide to Best Practices for Ocean CO2 Measurements. As to previous years’ work (Chierici et al., 2017), sampling of the water column at fixed sections was performed manually by IMR (Figure 1) aboard the institute's vessel F / F GM Dannevig in the North Sea, F / F Håkon Mosby in the Norwegian Sea and F / F Johan Hjort in the Barents Sea. UNI collected samples from the full water depth at Station M in the Norwegian Sea using IMRs research vessels Johan Hjort and Christine Bonnevie and the external vessels Vendla and Christina E. and the two western coastal stations in Hardanger were operated by R/V H. Brattstrøm. From these stations, hydrography, CT, AT, and nutrients were measured. In addition, UNI was responsible for continuous surface and sub-surface measurements at Station M, and the surface measurements covered pCO2 in sea and atmosphere, as well as pH, dissolved oxygen, and hydrography. In sub-surface water, pH and hydrography was continuously determined.

NIVA collected surface water samples manually on Ships of Opportunity equipped with FerryBoxes between Tromsø and Longyearbyen on the cargo ship M/S Norbjørn and between

Oslo and Kiel on the cruise ship M/S Color Fantasy. Continuous measurements of pCO2 were obtained for shorter periods on M/S Norbjørn, M/S Color Fantasy, in addition to the coastal ferry M/S Trollfjord that operates between Bergen and Kirkenes. The chlorophyll-a fluorescence sensor data was corrected for biofouling and calibrated using the chlorophyll-a measured from water samples.

The carbonate system in seawater can be described using four measurable parameters: total alkalinity (AT), total inorganic carbon (CT), pH, and partial pressure of CO2 (pCO2). AT is a measure of the capacity of seawater to neutralize acid (buffer capacity) and consists of the sum of the bases of the solution formed by weak acids (Eq. 4, Appendix 6.3). In seawater,

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carbonates and hydrogen carbonate form the largest part of these bases. CT is defined as the sum of carbonic acid and dissolved CO2 in water (CO2*), carbonates and hydrogen carbonates (Eq. 5, Appendix 6.3). The acidity or pH indicates the concentration of hydrogen ions (H+) in the seawater (Eq. 6, Appendix 6.3). The pCO2 is simply defined as the ratio of dissolved CO2* concentration in water and solubility of CO2 gas, K0 (Eq. 7, Appendix 6.3).

Throughout the report we have used pCO2 for the partial pressure of CO2. In fact, fCO2, which is the fugacity of CO2, is measured, which takes into account that CO2 is not an ideal gas. The difference between pCO2 and fCO2 is around 0.3%. In order to avoid the effects of continued biological activity in the water sample after it is collected, which will shift the balance of organic and inorganic carbon in the sample, the water samples for CT and AT are fixed with saturated mercury chloride solution. In addition, the samples are stored dark at approx. 4°C before being analysed. Discrete pH analyses were made immediately after sampling (NIVA).

2.2 Measurements of Total Alkalinity and Total Inorganic Carbon

Measurements of CT and AT were performed on water column samples from the sections Torungen-Hirtshals, Svinøy-NW, Gimsøy-NW, Fugløya-Bjørnøya, northeastern Barents Sea, Arendal coastal station, Skrova coastal station and cold-water coral reefs, from station M, from stations in Hardanger south of Bergen, and from surface water during the crossing Tromsø-Longyearbyen and Oslo-Kiel. The samples were analyzed by IMR, UNI and NIVA with VINDTA 3C (Marianda, Germany) and CM5011 coulometer (UIC instruments, USA). The measured values were calibrated against certified reference material (CRM) for quality assurance and as an accuracy check for all data (Certified Reference Material, CRM, A. Dickson, SIO, USA).

Sodium chloride salt is added to the hydrochloric acid for AT titration to be comparable to the ionic strength of natural seawater, about 0.7M, and the pH electrodes used by all groups are adapted to seawater samples / high ionic strength (Metrohm 6.0259.100). The VINDTA instruments at IMR and UNI use 20 ml and 100 ml sample volume for CT and AT, respectively.

NIVA uses approximately 250 ml in total for AT, CT, salinity and cleaning between samples. In the AT titrations, closed titration cells are used at all three institutions. Equivalence points were calculated using a curve fit method recommended by Dickson et al. (2007). The analysis method for determining CT concentrations is described in Johannessen et al. (2011).

2.3 pH Measurements NIVA used the spectrophotometric pH method onboard for determining in situ pH on the total scale (pHT). In situ pH was calculated using CO2SYS from pHT at in situ temperature, salinity and pressure (Pierrot et al., 2006). The measurements were performed on a HACH DR-2800 field spectrophotometer (5 cm cuvette) using m-cresol purple as the indicator dye in two concentrations and measurement from 434, 578 and 730 nm were used in calculations (SOP 6B; Dickson et al., 2007). Two replicates were measured for each sample. A potentiometric pH (Metrohm 680 pH-meter) was also measured on the NBS scale (pHNBS). The manual spectrophotometric pH measurements will be replaced with automatic spectrophotometric pH in the following years of the monitoring program.

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UNI measured in situ pH on the total scale using a spectrophotometric pH sensor from Sunburst Technologies, USA; the Submersible Autonomous Moored Instrument (SAMI2-pH). An indicator is mixed with seawater flowing through a cuvette, the pH of the seawater induces a colour change of the mixture and this is detected by a spectrophotometer. pH is calculated based on the detected colour change. This sensor was used at Station M.

2.4 pCO2 Measurements

UNI measured pCO2 using two technologies; infra-red and spectrophotometric detection. At rd the sea surface, pCO2 was detected every 3 hour using an instrument from Battelle Memorial

Institute, USA; the MAPCO2 system, which utilizes an air-water equilibrator at the sea surface and one reference gas (NOAA/ESRL) in addition to a zero-reference gas to frequently calibrate the system. The concentration of CO2 is detected by infra-red technology and pCO2 in both the air and in seawater is measured. In sub-surface water, the pCO2 was measured using a spectrophotometric pH sensor from Sunburst Technologies, USA; the Submersible Autonomous Moored Instrument (SAMI2-CO2). Seawater flows along a semi-permeable membrane, CO2 diffuses through the membrane and induces colour change in the indicator, which is detected spectrophotometrically. Both pCO2 systems were used at Station M.

Membrane-based pCO2 sensors were deployed on three FerryBox lines M/S Trollfjord (8 months coverage), M/S Norbjørn (2 months coverage), and M/S Color Fantasy (3 months coverage). The sensors were updated by the manufacturer in 2017 with new infrared CO2 detectors (Gassmitter, Sensors Europe Gmbh, Germany) with a lower volume equilibrium chamber, and new check valves and pressure regulators. Some preliminary data indicated that the check valves and pressure regulators, while designed to improve operation by reducing pressure build-up in the equilibration chamber, resulted in decreased flow rates that were below the specified flow rate required for proper CO2 equilibration between the seawater and air phases. The sensors had to be brought back for further testing in the lab and was therefore not operational for longer periods. Some of this work was carried out at the NIVA Research Station at Solbergstrand on a stationary FerryBox setup to troubleshoot and test the issues above.

2.5 Calculation of pH and Saturation State of Calcite and Aragonite

If two out of the four measurable parameters (CT, AT, pH and pCO2) are known then the other two can be calculated. In addition, the calculations yield the saturation states () of calcium carbonate bio-minerals: calcite (Ca) and aragonite (Ar). The degree of saturation is an indicator of the concentration of carbonates in the water, where  > 1 means the water is over-saturated with respect to carbonate. If  < 1 then the seawater is undersaturated with carbonate and the chemical environment is therefore unfavorable to organisms with carbonate shells, such as winged snails or coral reefs.

To calculate all of the carbon parameters, the chemical model CO2SYS is used (Pierrot et al.,

2006). The primary couple of parameters used are AT and CT alongside temperature, depth (pressure), salinity, phosphate and silica as input values for CO2SYS and the output includes in situ pH, pCO2, and saturation for calcite and aragonite. In these calculations, carbonic acid constants from Mehrbach et al. (1973), modified by Dickson and Millero (1987), were used. - The pH is given in total scale (pHT) and the constant for HSO4 from Dickson (1990) and in situ

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temperature is used in the pH calculations. Calcium ion concentration ([Ca2+]) was assumed to be proportional to the salinity (Mucci, 1983), and corrected for pressure according to Ingle (1975). NIVA measures pH directly in addition to using calculated pH from the CO2SYS program.

3. Results 3.1 North Sea and Skagerrak 3.1.1 Spatial variability along Torungen-Hirtshals section

Measurements were made at the five marked stations along the Torungen-Hirtshals section that was occupied in January 2017 (Figure 2). This region is affected by the warm and salty Atlantic waters (red) and fresh coastal waters (green, Figure 3). Position, depth and sampling data are displayed in Table 1, Appendix 6.2.

Figure 2. Stations from the Torungen-Hirtshals section in January 2017 and Arendal coastal station.

Figur 2. Stasjoner fra Torungen-Hirtshals snottet i januar 2017 og Arendal kyststasjon.

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Figure 3. Schematic map of the main currents in the North Sea and Skagerrak. The red arrows indicate the influx of Atlantic water, mostly at 100-200 m, while the green arrows indicate the main circulation patterns of coastal waters, typically in the top 20m (www.imr.no). The coastal stream receives deposits from the Baltic Sea.

Figur 3. Skjematisk kart over de viktigste transportveiene i Nordsjøen og Skagerrak. De røde pilene indikerer innstrømning av atlantisk vann, for det meste i 100-200 m, mens de grønne pilene angir hovedretningene til sirkulasjon av kystvann, typisk beliggende i de øverste 20m (www.imr.no). Kyststrømmen får tilførsler fra Østersjøen.

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Figure 4. pH and aragonite saturation state along the Torungen-Hirtshals section in January 2017.

Figur 4. pH og aragonittmetningsgrad langs snittet Torungen-Hirtshals i januar 2017.

Winter data from January 2017 show that pH had high values in the upper 50 m with maximum values towards the Norwegian and Danish coasts (Figure 4). This is due to the low

CT and AT values in the surface waters from the influence of freshwater (Figure 1, Appendix 6.1). The pH generally decreases with depth throughout the water column, with a strong vertical gradient identifying the warm Atlantic water layer between 50-250 m depth. Below 500 m depth, colder water occupied the deepest layers with the lowest pH occurs with highest AT and CT at 600 m depth in the central part of the section. This is likely to be affected by an older water mass with higher CO2 content from respiration.

The distribution of the saturation state for aragonite (and calcite, not shown) in 2017 had maximum values (Ω aragonite up to 2.0) in the upper layer, typically between 20-100 m depth. The saturation state was reduced at the sea surface at coastal stations at the northern and southern ends of the section. Within the Atlantic water, Ω aragonite was around 1.7 and saturation states followed a decreasing vertical gradient to minimum values close to 1.4 at 600 m depth.

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3.1.2 Seasonal variability at Arendal station

Measurements were made at Arendal coastal station from January to November 2017 (Figure 2). Position, depth and sampling data are displayed in Table 2, Appendix 6.2. This region is strongly influenced by the fresh coastal waters (green) in the upper 20 m and the warm and salty Atlantic waters (red) at deeper depths offshore (Figure 3).

Figure 5. Monthly temperature and salinity in the upper 80 m at Arendal coastal station. Black dots indicate sample depths.

Figur 5. Månedlig temperatur og saltholdighet I de gyerste 80 m ved Arendal kyststasjon. Svarte prikker viser prøvedyp.

The seasonal variability of salinity in 2017 show increased salinity throughout the water column due to the influence of warm and salty Atlantic water below 50 m depth (Figure 5). During the winter, the whole water column is relatively well mixed and cold at 4-6C until May. Seasonal warming stratifies the surface layers with temperatures exceeding 17C from June until October. Lower salinity in the upper 20 m in September and November is likely due to enhanced freshwater input from rivers and rainfall.

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Figure 6. Monthly nitrate and dissolved inorganic carbon in the upper 80 m at Arendal coastal station. Black dots indicate sample depths.

Figur 6. Månedlig nitrat and totalt uorganisk karbon i de gyerste 80 m ved Arendal kyststasjon Svarte prikker viser prøvedyp.

-1 High CT values of 2160-2190 μmol kg and higher nitrate concentrations (Figure 6) were found below 40 m depth from incursions of Atlantic water towards shallower depths. Biological -1 production reduced CT concentrations to less than 2100 μmol kg , alongside depletion of nitrate, reaching minimum values of 1900-1950 μmol kg-1 in the surface layer from summer to autumn.

High pH ( 8.1) was found in the upper 20 m with maximum values in spring, summer and autumn (Figure 7). The influence of Atlantic water layer could be distinguished by lower pH ( 8.0) water being projected upwards in the water column. The saturation state for aragonite (and calcite, not shown) by late summer was higher relative to winter values (Ω aragonite  2.0) in the whole water column with maximum values (Ω aragonite up to 2.4) in the upper 20 m. Reductions in pH and Ω aragonite at the sea surface during summer occurred within localised reductions of salinity from freshwater inputs. The saturation state was reduced at the sea surface to minimum values (Ω aragonite  1.5) during the winter.

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Figure 7. Monthly pH and aragonite saturation state in the upper 80 m at Arendal coastal station. Black dots indicate sample depths.

Figur 7. Månedlig pH og metningsgrad av aragonitt i de gyerste 80 m ved Arendal kyststasjon Svarte prikker viser prøvedyp.

3.1.3 Seasonal variability in surface water

The stations covered using M/S Color Fantasy going between Oslo-Kiel are shown in Figure 8. Position, depth and sampling data are displayed in Table 12, Appendix 6.2. The Skagerrak is influenced by freshwater runoff and rivers, Atlantic water and Baltic water. The three northernmost stations cover the Oslofjord, where Oslo is situated at about 60 N.

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.

Figure 8. Stations from Oslo-Kiel in 2017. 16.1 (red ▲); 6.5 (blue ●); 29.8 (black ▼ ) ; 2.11 (green ■).

Figur 8. Stasjonskart for snittet mellom Oslo-Kiel, 16.1 (rød ▲), 6.5 (blå ●), 29.8 (sort ▼) og 2.11 (grønn ■).

The seasonal variation of temperature and salinity since 2012 is shown in Figure 9. The average temperature for the Skagerrak stations reached as low as 3.48 C in the winter and as high as 16.91 C in summer. The salinity was unusually high in the Oslofjord during winter, otherwise both Skagerrak and the Oslofjord showed a normal range of seasonal variation of salinity, with freshwater influenced waters during summer and autumn. The average salinities for the Skagerrak stations reached as low as 24.75 in spring and as high as 29.56 in winter.

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Figure 9. Measured in situ salinity and sea surface temperature in the Oslofjord and Skagerrak. The circles show the measured values, while the interpolated values are shown in the background.

Figur 9. Målt saltholdighet og temperatur i overflatelaget i Oslofjorden og Skagerrak. Ringene viser målte verdier, mens interpolerte verdier vises i bakgrunnen.

The seasonal variation of pH and aragonite saturation since 2012 is shown in Figure 10. The pH showed very small seasonal variations during the cruises in 2017. The average pH for the Skagerrak stations was highest (8.07) during winter, and was low during summer (8.02) and autumn, but low variability was seen overall, in contrast to earlier years where biological production raised the pH during summer.

The aragonite saturation (calculated from AT and CT) reached the lowest state during winter and had higher values during summer and autumn. The saturation was as low as 1.49 on average in the Skagerrak during spring and as high as 2.11 during autumn. The aragonite saturation was <1 in the inner Oslofjord station during the autumn, as seen in previous years, but the fjord was in a better state than in 2015 and 2016 when the saturation didn’t recover much during the summer.

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Figure 10. pHT and Omega Aragonite, calculated from CT and AT, in the Oslo fjord and Skagerrak. The circles show the measured values, while the interpolated values are shown in the background.

Figur 10. pHT og Omega Aragonitt, beregnet fra CT og AT) i Oslofjorden og Skagerrak. Ringene viser målte verdier, mens interpolerte verdier vises i bakgrunnen.

The seasonal and interannual variation of seawater temperature, salinity, pH and aragonite saturation state shown in Figures 9-10 is based upon observations from cruises over 6 years. This time series is starting to show what the normal range of variation is, and it makes it possible to identify unusual variation, such as the relatively low pH observed during summer 2017 in the Skagerrak. By using some data from the ‘ØKOKYST’ program monitoring we looked at how representative our data was for showing the influence of biological production on pH.

Figure 11. Stations in the OA monitoring (circles) and chlorophyll-a fluorescence during the year.

Figur 11. Stasjoner fra havforsuringsprogrammet (punkt) og klorofyll a fluorescens over året.

In Figure 11 the stations were plotted against the continuous data of calibrated and quality controlled chlorophyll-a fluorescence. It shows how the cruises did not overlap with a period of elevated chlorophyll-a fluorescence. Higher chlorophyll-a fluorescence implies higher phytoplankton biomass and production and therefore a drawdown in CO2 and increase in pH.

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The higher pH observed in the inner Oslofjord (northernmost sample; ~59.8°N) in May 2017 followed a prolonged period of higher chlorophyll-a fluorescence and likely biological production from March to May 2017.

3.1.4 Trend analysis at selected stations

3.1.4.1 Trend analysis by linear regression

Shown in Figure 12 below are the trend analyses using linear regression on annual average surface winter data from the mid Skagerrak area.

Figure 12. Linear regression trends in temperature, salinity, pH, aragonite saturation state in surface (4 m) waters from 2011 to 2017 in the Skagerrak.

Figur 12. Lineær regresjon i temperatur, saltholdighet, pH og metningsgrad av aragonitt av midlede overflatedata (4 m) fra vinter 2011 til 2017 i Skagerak

The temporal changes in the whole water column and the time-trend analyses (Figures 13- 14) at the deepest station (600 m depth) from the Torungen-Hirtshals section are shown below.

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Figure 13. Eight years (2010-2017) of data of pH and aragonite saturation from the station with 600 m water depth along the Torungen-Hirtshals section in central Skagerrak.

Figur 13. Åtte års (2010-2017) malinger av pH og metningsgrad av aragonitt fra stasjonen med 600 m dybde på Torungen-Hirtshalssnittet i sentrale Skagerak.

The distribution of pH throughout the whole water column from 2010 to 2017 at the central station with greatest water depth (to 600 m) shows that the largest variation occurred in the upper 50 m (Figure 13). However, pH values below 500 m depth generally decreased over time from 8.02 to less than 7.94 by 2017. The variation in the saturation state for aragonite throughout the whole water column from 2010 to 2017 at the central station followed a similar pattern to pH. Greatest variations occurred in the dynamic upper layers and values of Ω aragonite in deep water layer decreased over time from around 1.5 to 1.3-1.4 by 2017.

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Figure 14. Yearly trend analyses in temperature, salinity, pH and aragonite saturation state at 600 m depth from the station in central Skagerrak along the Torungen-Hirtshals section.

Figur 14. Årlig trendanalyse av temperatur, saltinnhold, pH og aragonittmetning ved 600 m dyp på stasjonen i sentrale Skagerrak langs Torungen-Hirtshals snittet.

The changes in pH and Ω aragonite in the deepest water mass are affected by increased temperature by almost 3C in 7 years, a rate of 0.31C yr-1, as measured at 600 m depth (Figure 14). This was accompanied by a general increase in salinity, indicating a greater incursion of warm and saline water masses into the Skagerrak region. This resulted in a decreasing time trend of pH and aragonite saturation at 600 m in 7 years, giving an average pH reduction of 0.013 per year.

3.1.4.2 Trend of fCO2 drivers

The effects of temperature (ΔfCO2temp), biological production (ΔfCO2bio), and the sum of air-sea CO2 gas exchange and mixing of high CO2 waters from below the mixed layer

(calculated as a mass balance; ΔfCO2as-mix) were assessed as drivers of seasonal variation in fCO2 using the methodology described in Chierici et al. (2006) and references therein. Briefly, the contributions of the various drivers to the fCO2 variability at approximately 58.5°N on the

Oslo-Kiel transect in the period between 2014-2017 were estimated using fCO2 (calculated from CT/AT), sea surface temperature, nitrate concentration at the surface and estimated for below the mixed layer (Figure 15). The largest, negative driver (drawdown) of fCO2 variability was biological production, accounting for roughly -150 µatm fCO2 during each spring bloom. The springtime decline in fCO2 was counteracted by an increase in fCO2 due to effect of increased sea surface temperature as well as the combined effect of air-sea interactions and mixing from below the mixed layer.

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fCO temp 200 2 fCO2bio

fCO2as+mix 150

100

50

0

(microatm)

2 -50

fCO

-100

-150

-200

Jul-2014 Jul-2014 Jul-2015 Jul-2016 Jul-2017

Jan-2014 Jan-2014 Jan-2015 Jan-2016 Jan-2017 Jan-2018

Apr-2014 Apr-2014 Apr-2015 Apr-2016 Apr-2017

Oct-2014 Oct-2014 Oct-2015 Oct-2016 Oct-2017

Figure 15. Drivers of seasonal difference of fugacity of ΔfCO2 (µatm) between air and sea in the Skagerrak.

Figur 15. Drivere av sesongvariasjoner i ΔpCO2 (µatm) i Skagerak.

3.2 Norwegian Sea

3.2.1 Spatial variability along the Svinøy-NW section

In 2017, carbon chemistry measurements were carried out on water samples from the full water column at fixed stations along the hydrographic section between Svinøy and 6440' N, 00' E; Svinøy-NW. The samples were collected in February and May by IMR (Figure 16). Position, depth and sampling data are displayed in Table 5, Appendix 6.2.

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Figure 16. Map and numbers of the stations from Svinøy-NW in the Norwegian Sea in February and May 2017.

Figur 16. Kart og nummer over stasjoner langs Svinøy-NV i Norskehavet i februari og mai 2017.

The Svinøy-NW section encompasses the coastal waters (fresh with high seasonal variability in temperature) and parts of the Atlantic waters and Arctic waters in the Norwegian Sea (Figure 17).

Figure 17. Major currents and water masses in Norwegian Sea: Atlantic water (red), polar water (blue) and coastal water (green). www.imr.no.

Figur 17. Strømmer og hovedsakelige tre vannmasser i både Norskehavet og Barentshavet: atlanterhavsvann (rød), arktisk vann (blå) og kystvann (grønn).

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Warm and salty Atlantic waters flow into the Norwegian Sea between Shetland, the Faroe Islands and Iceland and follows the topography northwards. The Atlantic waters cool down on their way north and absorb a lot of atmospheric CO2. This section has hydrographic sampling history back dating to 1935

The distribution of pH along the Svinøy section in 2017 shows lower values in the range 8.04- 8.05 in the Atlantic waters down to 400 m (Figure 18). Low surface water pH was found close to the coast, from low AT and CT, due to the presence of relatively colder and fresher waters of the Norwegian coastal current (Figure 2, Appendix 6.1). Below 500 m depth, colder water referred to as Arctic Intermediate Water, originating in the Arctic, occupied the deepest layers with reduced AT compared to the Atlantic water and the lowest pH in the deep

Norwegian Sea. The underlying water between 500 and 1000 m depth has the highest CT -1 concentrations (2170-2180 μmol kg ) and the in deepest water layer CT was slightly lower (about 2165 μmol kg -1). Low pH values (8.02) were found at 2500 m depth furthest in the northwest.

The saturation state for aragonite (and calcite, not shown) varied from highest values as a result of seasonal biological CT uptake at the surface to lowest in the deepest parts of the section. Saturation states in the surface varied between 1.8 and 2.0, which is a result of the impacts of different processes such as freshwater inputs, biological production and mixing of Atlantic waters. The upper 400 m of the water column was saturated with respect to aragonite (Ω aragonite > 1.8), which had a decreasing vertical gradient. Underlying the Atlantic water is the fresher Arctic water, which is distinguished by a core of lower Ω aragonite values (1.3-1.5) and the saturation horizon for aragonite occurred between 2000- 2400 m depth. Waters below 2400 m were undersaturated (Ω aragonite < 1.0).

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Figure 18. pH and aragonite saturation state along the Svinøy-NW section in February and May 2017.

Figur 18. pH og aragonittmetningsgrad langs Svinøy-NV snittet i februar og mai 2017.

3.2.2 Spatial variability along the Gimsøy-NW section

Measurements of carbon chemistry in the full water column along Gimsøy-NW in the northern part of the Norwegian Sea were carried out in April 2017 (Figure 19). A total of 6 hydrographic stations were occupied from the Lofoten basin to the Norwegian Sea. Position, depth and sampling data are displayed in Table 7, Appendix 6.2.

The Gimsøy-NW section encompasses part of the Norwegian coastal current, recycled Arctic water at intermediate depths and Atlantic waters that flow northwards into the Barents Sea. In this region there are numerous cold-water coral reefs and these calcium carbonate environments are potentially particularly sensitive to low aragonite saturation states. This area is also, together with the Norwegian basin, one of the places where pH has decreased at a faster rate compared to other parts of the Norwegian Sea (Skjelvan et al., 2014).

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Figure 19. Map and numbers of the stations along the Gimsøy-NW section in the northern Norwegian Sea in April and June 2017.

Figur 19. Kart og nummer over stasjoner langs Gimsøy-NV snittet i nordlige Norskehavet i april og juni 2017.

The Gimsøy-NW section crosses the northern Norwegian Sea, with fresh water near the coast and approx. 40 km northwest (Figure 17). The distribution of pH in 2017 is dominated by warm and salty Atlantic water in the upper layers overlying cold Arctic water at intermediate depths (Figure 20). Further from the coast, Atlantic water occupies the upper layers down to approx. 500 m with relatively high CT and AT values of approximately 2150-2160 and 2325 μmol kg-1, respectively (Figure 3, Appendix 6.1). pH was around 8.07-8.10 at the offshore end of the section.

Aragonite (and calcite, not shown) saturation showed a general decreasing gradient from highest values (Ω aragonite > 2) in the sunlit productive surface waters to the deepest parts of the section, reaching close to saturation levels (1.03) at 2000 m (Figure 20). Lower AT and

CT in the coastal current yield lower values of pH and aragonite saturation states (Ω aragonite 1.8-1.9) compared to surface waters further into the Norwegian Sea. Lowest pH values were found in the bottom water of the Lofoten basin of approx. 2000 m deep. In the deeper parts of the Norwegian Sea, the recycled water from the Arctic is characterized by higher CT and -1 lower AT values (approx. 2170-2190 and 2310 μmol kg , respectively) compared to the Atlantic water. The pH is about 8.04. High pH water 8.08-8.10 was detected near the continental slope at 1500 m depth extending to 100-200 km from the coast.

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Figure 20. pH and aragonite saturation state along the Gimsøy-NW section in April and June2017.

Figur 20. pH og aragonittmetningsgrad langs Gimsøy-NV snittet i april og juni 2017.

3.2.3 Seasonal variability in open ocean

3.2.3.1 Station M

Seasonal variation of Norwegian Sea water has been determined using data from the Ocean Weather Station M (Station M), which is positioned between the Svinøy-NW and Gimsøy-NW sections at 66°N 2°E (Figure 1). From this position, the carbon cycle has been monitored since 2001, while the hydrographic monitoring dates to 1948. In 2017, UNI has collected discrete water samples between surface and deep at five cruises and the samples (12 from each cruise) have been analysed for CT and AT (Table 6, Appendix 6.2). Additionally, a buoy equipped with a variety of sensors has continuously measured surface pCO2 and pH at the station. A deep mooring was deployed in November 2017 and it will be retrieved in May 2018, and pH data from 500 m deep will be quality assured and made ready for presentation for the 2019 report.

Discrete and continuous measurements from the same station provide supplementary information. The discrete measurements describe the seasonality of the carbonate system over the full water depth, while the continuous measurements describe the variability over a variety of time scales; from days to years, however, this information is only available from a

36 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 few selected depths. At Station M, the continuous monitoring is performed in the surface water, and, currently, at 500 m depth.

The Norwegian Atlantic Current flows northwards off the Norwegian coast and influences both the Svinøy and Gimsøy sections as well as Station M. The Norwegian Atlantic Current has a thickness of 300–500 m at Station M, and within this layer salinity, temperature, and the carbonate variables are affected by the relatively warm Atlantic water (Figures 21 to 26). During winter, the surface temperature was approximately 7.5°C, while during summer, the water warmed to approximately 12°C. These values were confirmed by the continuous buoy measurements from the station (January and February surface temperature of 7.5±0.3°C and 7.6±0.4°C, respectively, and August surface temperature of 12.3±0.4°C). In 2017, the marine blooming, identified by a decrease in CT and an increase in pH and ΩAr (Figure 24 to 26), started in late April early May, which was slightly later than previous years. Chapter 6.1 shows in detail the seasonal cycle of surface pH and ΩAr over the years 2011 to 2017.

Figure 21. Salinity at Station M in 2017. Black dots indicate the depths of the samples.

Figur 21. Saltinnhold på Stasjon M i 2017. Svarte prikker viser prøvedyp.

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Figure 22. Temperature (°C) at Station M in 2017. Black dots indicate the depths of the samples.

Figur 22. Temperatur (°C) på Stasjon M i 2017. Svarte prikker viser prøvedyp.

The seasonal changes were seen in the upper 100-150 m, and deeper than this, the changing water characteristics were decoupled from seasons and might rather be connected to mixing of water masses which occurs with variable frequency and strength. The intermediate water occupies the area below the Norwegian Atlantic Current and this water mass extends from approximately 500 to 1000 m depth. Below the intermediate water, i.e. deeper than approximately 1000-1200 m, the Norwegian Basin is filled with relative fresh and cold water, with relative stable characteristics; however, changes are seen over years (Skjelvan et. al., 2008; Skjelvan et. al., 2014). In 2017, the deep water at

Station M held the following characteristics; temperature of -0.78°C, salinity of 34.91, AT -1 -1 of 2306 µmol kg , CT of 2163 µmol kg , pH of 8.04, and ΩAr of 1.04.

The saturation horizon was found around 2000 m depth in 2017 (Figure 26), i.e. deeper than previous years, which illustrates the variability of the system and the importance of long time series. Thus, it should be kept in mind that only two of the 2017 cruises to Station M collected samples from the deepest water. Winter surface water characteristics -1 in 2017 were for CT, pH and ΩAr 2149 µmol kg , 8.04 and 1.86, respectively, and the corresponding summer characteristics were 2072 µmol kg-1, 8.13 and 2.57. The winter pH and ΩAr values were confirmed by the continuous buoy measurements from the station.

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-1 Figure 23. AT (total alkalinity; mol kg ) at Station M in 2017. Black dots indicate the depths of the samples.

-1 Figur 23. AT (total alkalinitet; mol kg ) på Stasjon M i 2017. Svarte prikker viser prøvedyp.

-1 Figure 24. CT (total dissolved inorganic carbon; mol kg ) at Station M in 2017. Black dots indicate the depths of the samples.

-1 Figur 24. CT (totalt løst uorganisk karbon; mol kg ) på Stasjon M i 2017. Svarte prikker viser prøvedyp.

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Figure 25. pH in situ at Station M in 2017. Black dots indicate the depths of the samples.

Figur 25. pH in situ på Stasjon M i 2017. Svarte prikker viser prøvedyp.

Figure 26. Ar (saturation state of aragonite) at Station M in 2017. Black dots indicate the depths of the samples.

Figur 26. Ar (metningsgrad av aragonitt) på Stasjon M i 2017. Svarte prikker viser prøvedyp.

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In general, the buoy at Station M is in the water between June/July and March/April in the subsequent year (discrepancies from this do occur), and even though raw data are available on a daily basis, the corrected data are not available until the buoy is retrieved, which is why we will always be delayed in presenting buoy data. In retrospect, the continuous data from the buoy from July and November 2016 have been compared with discrete surface measurements during the same period of time, and the continuous measurements seem to be slightly higher than the discrete data, the latter being single data points (July 2016:

continuous pH=8.150±0.006 and ΩAr=2.80±0.03 and discrete pH=8.136 and ΩAr=2.73;

November 2016: continuous pH=8.073±0.004 and ΩAr=2.034±0.017 and discrete: pH=8.058

and ΩAr =1.96).

3.2.4 Seasonal variability in coastal water

3.2.4.1 Hardanger - west coast

Between June and November 2017, UNI has collected carbon samples from the full water column at two stations in Hardanger at the west coast; Hardangerfjord and Langenuen. Position, depth and sampling data are displayed in Tables 3-4, Appendix 6.2. Figure 27a-h show a selection of parameters where the left panel of figures are from the Hardangerfjord station while those to the right are from Langenuen. Both stations are from the inner coast, and the Langenuen station, which is approximately 200 m deep, is from a relatively narrow strait north of the Hardangerfjord station, the latter being ca. 350 m deep.

Water is in general entering the area form the south, however, this changes from time to time. The deep water at our stations has primarily Atlantic origin, while the shallower water has coastal and local origins. The mixing of the water column is forced by local winds as well as seasonal temperature changes and run off from land. The summer warming is clearly seen in Figure 27a-b, and during September a local minimum in salinity occurred in Langenuen most likely connected to heavily rainfall during the days prior to sampling. pH and ΩAr increase as a response to biological production. The maximum pH occurs earlier than that of

ΩAr because rising temperature during summer makes the pH decrease. Langenuen station shows less distinct changes in pH and ΩAr compared to what is observed at Hardangerfjord station.

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Figure 27. 2017 data from Hardangerfjord station; a) temperature (°C), c) salinity, e) pH, and g) Ar, and from

Langenuen station; b) temperature (°C), d) salinity, f) pH, and h) Ar. Black dots indicate the depths of the samples.

Figur 27. 2017-data fra stasjonen i Hardangerfjorden; a) temperatur (°C), c) saltinnhold, e) pH og g) Ar, og fra stasjonen i Langenuen; b) temperatur (°C), d) saltinnhold, f) pH og h) Ar. Svarte prikker viser prøvedyp.

3.2.4.2 Skrova

Station Skrova, in the Lofoten basin at 68.1⁰N, 14.5E, has been sampled for carbon chemistry variables by IMR monthly since 2015. Position, depth and sampling data are displayed in

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Table 8, Appendix 6.2. This time series provides data on seasonal variation of inorganic carbon in the Norwegian Coastal Current (Figure 28).

Figure 28. The location and current pattern in the Lofoten area. Green arrows indicate Coastal Current patterns, Red arrow indicate the Norwegian Atlantic Current. Skrova station is marked by a black circle.

Figur 28. Kart over Lofoten som viser de viktigste strømmene. Grønne piler viser kyststrømmen og rød pil viser den norske Atlanterhavsstrømmen. Zwart prikk viser Skrova kyststasjon.

Biological activity is an important aspect of the overall understanding of ocean acidification due to the interaction between, for example, primary production and respiration that induces a strong signal in both processes throughout a daily cycle and over a season. Temperature (Figure 29) and salinity (Figure 30) show that in January the upper 100m layer was mixed, and then the mixed layer shallowed rapidly to about 60m depth and continued shallowing until the middle of May. During June to August the mixed layer was about 30 meters, and from the end of August the mixed layer expanded until it reached 100m depth at the end of the year.

Figure 29. Monthly variation in temperature at the coastal station Skrova 2017.

Figur 29. Månedvis variasjon av temperatur ved kyststajon Skrova i 2017.

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Figure 30. Monthly variation in salinity at the coastal station Skrova 2017.

Figur 30. Månedvis variasjon av saltholdighet ved kyststajon Skrova i 2017.

Figure 31. Monthly variation in pH at the coastal station Skrova 2017.

Figur 31. Månedvis variasjon av pH ved kyststajon Skrova i 2017.

Figure 32. Monthly variation in Ω aragonite at the coastal station Skrova 2017.

Figur 32. Månedvis variasjon av aragonittmetningsgrad ved kyststajon Skrova i 2017.

The distribution of pH (Figure 31) shows higher and variable values in the upper 50 m, with maximum values during the spring. Highest aragonite saturation states occurred in the second

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These patterns were driven by changes in CT with fluctuations in the upper mixed layer from winter values averaged 2065 µmol kg-1 (std=10.5, N=20) to 1999 µmol kg-1 (std=30, N=15) by midsummer in 2017, driven by uptake of inorganic carbon by photosynthesis. Below 200 m, pH was typically less than 8 and saturation states decreased to 1.5-1.6 most of the year.

3.2.5 Trend analysis at selected stations

Discrete and continuous data from Station M over the years 2011 to 2017 have been examined, and Figure 33 shows how surface pH and Ar change over the years, while Figure 34 shows changes at 2000 m depth. For the surface water, only the winter data (January to March) have been included to avoid the biologically active season.

Figure 33. Winter surface water trends of (a) pH and (b) Ar calculated from discrete samples, and (c) pH and (d)

Ar calculated from continuous measurements (monthly averages) at Station M during the years 2011-2017.

Figur 33. Endring i overflate (a) pH og (b) Ar beregnet fra diskrete prøver og (c) pH og (d) Ar beregnet fra kontinuerlige målinger (månedsmidler) fra Stasjon M i årene 2011 til 2017. Bare vinterdata er brukt.

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The surface water showed an annual decrease in pH and Ar of 0.003 and 0.015, respectively, based on discrete samples (Figure 33a-b). The correlations were not particularly strong, however, the trends based on continuous measurements from the surface buoy at Station M were more robust and confirmed the picture by even slightly stronger annual decreases of ca.

0.005 and 0.016, respectively, for pH and Ar (Figure 33c-d). These values are comparable to the negative trends estimated for the Norwegian Basin by Skjelvan et al. (2014) of -0.0041 and -0.012 for pH and Ar, respectively.

Figure 34. Trends at 2000 m deep of (a) temperature,

(b) pH, and (c) saturation state of aragonite (Ar) at Station M during the years 2011-2017.

Figur 34. Endring i (a) temperatur, (b) pH og (c)

metningsgrad av aragonitt (Ar) på 2000 m dyp i årene 2011 til 2017 på Stasjon M.

The deep water gradually changes towards a more acidic situation, except for 2017, where a minor increase in deep water pH and Ar are seen. The water at 1950 to 2050 m depth warms by an amount of 0.0058°C yr-1 (Figure 34a), which is comparable to earlier studies by e.g. Skjelvan et. al. (2014). The warming can be explained by the reduced deep-water formation in the Greenland Sea and subsequent change in the water exchange between the deep Arctic and the deep Norwegian and Greenland Basin. Annually, the deep-water pH and Ar have decreased by 0.003 and 0.008, respectively (Figure 34b-c), which is slightly less but still comparable to the deep-water trends from previous years.

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In Skjelvan and Omar (2015) and Skjelvan et al. (2016), coastal data from Hardanger in 2015 and 2016 has been presented. Here, trends of deep pH and ΩAr from Hardangerfjord and Langenuen stations over the years 2015 to 2017 have been determined by linear regression (Figure 35a-b). There is a positive trend in the deep water at the two stations, however, the time series are short, the correlation is poor, and it is difficult to conclude.

Figure 35. Deep data showing (a) pH from Hardangerfjord (blue o) and Langenuen (black x) stations in 2017, (b) Ar from Hardangerfjord (blue o) and Langenuen (black x) stations in 2017, (c) pH from Korsfjord station 2007-2017, and

(d) Ar from Korsfjord station 2007-2017.

Figur 35. Dype data av (a) pH fra Hardangerfjorden (blå o) og Langenuen (svart x) i 2017, (b) Ar fra

Hardangerfjorden (blå o) og Langenuen (svart x) i 2017, (c) pH fra Korsfjorden 2007-2017, og (d) Ar fra Korsfjorden 2007-2017.

To give an impression of the importance of long costal time series, we include a comparison performed at a coastal station north of Langenuen; Korsfjord station, where UNI has carbon data from the period 2007-2010 in addition to 2015 to 2017 (Figure 35c-d). This station is approximately 670 m deep and the fjord is relatively open to the outer coast and the

Norwegian Sea. Deeper than 600 m we see a significant annual decrease of both pH and ΩAr of -0.007 and -0.02, respectively. We are not aware of comparable coastal time series, but the trends are stronger compared to elsewhere in the Norwegian open ocean. More effort must to be put into understanding these results, which is a task for the future.

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Further analysis of temporal changes in the Norwegian Sea can be identified from the hydrographic station located at 1E (Figure 16) along the Svinøy-NW section. The distribution of pH from 2011 to 2017 shows strong year-to-year variation throughout the whole water column to 2500 m depth (Figure 36). The values of pH in the core of Atlantic water to around 400 m depth were consistently in the range 8.04-8.05. The pH in the colder and fresher Arctic water mass was more variable, with elevated pH to 8.11, most notably in 2011 and 2017.

Figure 36. Seven years (2011-2017) of data of pH and aragonite saturation at the 1°E station along the Svinøy-NW section.

Figur 36. Syv års (2011-2017) malinger av pH og metningsgrad av aragonitt ved stasjonen 1°E langs Svinøy-NV snittet.

The year-to-year distribution of the saturation state for aragonite was more consistent compared to pH. Saturation in the upper layers (Ω aragonite > 1.6) was a consistent feature in the timeseries with a strong decreasing vertical gradient into the Atlantic water. Mid-depths of the section were occupied by the fresher Arctic water, which could be distinguished by variable but lower aragonite saturation states (Ω aragonite 1.2-1.5). The depth of the saturation horizon varied from above and below 2000 m depth during the time series, as is also seen at Station M further north. The deepest levels of the Svinøy section were consistently undersaturated with respect to aragonite.

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Figure 37. Yearly trend analysis in temperature and aragonite saturation state at 1000, 1500, 2000, 2500 m depth from the 1E station along the Svinøy-NW section.

Figur 37. Årlig trendanalyse av temperature og aragonittmetning ved 1200-1500 m 1000, 1500, 2000 2500 m dyp på stasjonen 1 °E langs Svinøy-NV snittet.

The seawater temperature and aragonite saturation state at 1000, 1500, 2000 and 2500 m for the 1ºE station along the Svinøy section shows interannual variability related to the variations in the presence of Arctic water at these locations (Figure 37). The temperature at 1000 m is more variable compared to the deeper depths, perhaps due to interactions of the comparatively cold Arctic water with the overlying warm and salty Atlantic water. This is also the case for the distribution of Ω aragonite, showing higher values around 1.40 in 2011 and 2017. However, a slight increasing trend in seawater temperature since 2011 and increased aragonite saturation from 2012 could be identified at 1000 and 1500 m.

Analysis of temporal changes in northern the Norwegian Sea can be identified from the hydrographic station located at 12.3E (Figure 19) along the Gimsøy-NW section. The distribution of pH from 2011 to 2017 shows relatively little year-to-year variation in the upper 1500 m compared to the Svinøy section in the southern Norwegian Sea (Figure 38). The pH values in the core of Atlantic water to around 500 m depth were consistently in the range 8.06-8.09. The pH in the colder and fresher Arctic water mass was generally more variable ranging from 8.02-8.05.

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Figure 38. Five years (2011, 2014-2017) of data of pH and aragonite saturation at the station at 12.3 °E along the Gimsøy-NW section.

Figur 38. Fem års (2011, 2014-2017) malinger av pH og metningsgrad av aragonitt ved stasjonen ved 12.3°E langs Gimsøy-NV snittet.

The saturation state for aragonite was more stable from year to year compared to pH, with saturation (Ω aragonite > 1.6) in the upper layers and a strong decreasing gradient with depth through the Atlantic water layer throughout the time series (Figure 38). Mid-depths of the section were occupied by the fresher Arctic water, which could be distinguished by lower aragonite saturation states (Ω aragonite 1.1-1.4).

The seawater temperature and salinity at 1200-1500 m depth for the 12.3ºE station along the Gimsøy-NW section shows interannual variability related to the variations in the presence of the overlying warm and salty Atlantic water and the cold, fresh Arctic water below (Figure 39). General trends since 2011 show increasing temperature and salinity of 0.025 C yr-1 and -1 -1 0.004, respectively. These changes were accompanied by increases in CT of 2.4 µmol kg yr -1 -1 and most notably AT of 5.0 µmol kg yr . As such, values of pH and the saturation state of aragonite have tended to increase, with a large degree of variability, at these depths from 2011 to 2017.

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Figure 39. Yearly trend analysis in temperature, salinity, CT, AT, pH and aragonite saturation state at 1200-1500 m deep at station 12.3 E along the Gimsøy-NW section

Figur 39. Årlig trendanalyse av temperature, saltholdighet, CT, AT, pH og aragonittmetning ved 1200-1500 m dyp på stasjonen 12.3 °E langs Gimsøy-NV snittet.

At Skrova coastal station in the Lofoten basin (Figure 1) there was considerable variation in pH and aragonite saturation state in the water column in the three years studied (Figure 40).

The 2015 and 2017 data showed similar summer consumption of CO2, in increases in both variables, but the duration and depth of seasonal maxima were much smaller in 2016.

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Figure 40. pH and aragonite saturation state in the water column during 2015-2017 at Skrova station.

Figur 40. pH og aragonittmetning in vannkolonna i perioden 2015-2017 ved Skrova stasjon.

These fluctuations are more related to the changing of the waters in the Norwegian current in general, which has variable exchange with Atlantic water, and this is also reflected in salinity and temperature fluctuations. However, the pattern in the upper mixed layer is repeated every year as a function of the spring bloom of phytoplankton and the productive season of photosynthesis and biological carbon uptake, leading to increases in pH and the levels of aragonite saturation.

3.3 Barents Sea 3.3.1 Spatial variability along the Fugløya-Bjørnøya section

In April 2017, carbon chemistry measurements were carried out throughout the water column at five fixed stations along the hydrographic section between Fugløya-Bjørnøya in the southeastern Barents Sea (Figure 41). The Barents Sea is relatively shallow with maximum depths of around 400 m, compared to deeper ocean basins like the Norwegian Sea. Position, depth and sampling data are displayed in Table 9, Appendix 6.2.

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Figure 41. Map and station numbers from stations along the Fugløya-Bjørnøya section in February and April 2017 and in the northeastern Barents Sea in September 2017.

Figur 41. Kart og nummer over stasjoner langs Fugløya-Bjørnøya snittet i februar og april 2017 og i nordøstlige Barentshav i September 2017.

Figure 42. Map showing major currents in the Barents Sea. Red arrows show Atlantic water, green coastal current and blue arrows show the Arctic water. Grey line shows the position of the polar front. Map from www.imr.no.

Figur 42. Kart som viser hovedstrømmene i Barentshavet. Røde piler viser atlantisk vann, grønne piler er kyststrømmen og blå piler viser arktisk vann. Grå linje viser omtrentlig posisjon til polarfronten. Kart fra www.imr.no.

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The Fugløya-Bjørnøya section, southern Barents Sea, extends into the coastal current in the southernmost station and passes through the region where Atlantic waters flow into the Barents Sea and continue passage northwards into the Arctic Ocean (Figure 42). The entire water column to the deepest station (at approximately 73N) on average is affected by the Norwegian coastal water with relatively low salinity and homogeneous temperature of between 5,5 and 7 C (Figure 4, Appendix 6.1). The central part of the section deepened to 500 m depth at 73.5N in the Barents Sea where Atlantic water with salinity >35.1 and temperature ~6C occupied the upper layers. Further north, the water becomes less salty towards Bjørnøya where the Atlantic waters meet the relatively fresh and cold Arctic waters.

Figure 43. pH and aragonite saturation state along the Fugløya-Bjørnøya section in February and April 2017.

Figur 43. pH og aragonittmetningsgrad langs Fugløya-Bjørnøya snittet i februar og april 2017.

Near Bjørnøya the inflow of polar waters travelling south from north east Svalbard creates strong horizontal gradients at the polar front northwards from 73.5N that lead to reduced salinity (< 34.7) and lower temperatures (< 1C) in the upper 100 m at the northern end of the section. The distribution of AT reflects the key water masses of this region of the Barents Sea; coastal water, Atlantic water and Arctic water. Between 71.5 and 73 N, the Atlantic water -1 has high and homogenous AT of 2325-2330 μmol kg with a strong horizontal gradient in AT to lowest values around 2300 μmol kg-1 in the polar water (Figure 4, Appendix 6.1).

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Water column pH was also comparatively homogenous with values around 8.07-8.08 south of

73.5N (Figure 43). The distribution of CT showed a slightly different pattern, with a northward decreasing gradient in surface waters with values of approx. 2130 μmol kg-1 at Bjørnøya. This was accompanied by high pH (>8.16) in the upper 100 m of the water column. Lowest pH values around 8.06 were found in the deepest water at 72.5-73.8N. The saturation state for aragonite had a general decreasing gradient with depth, with homogenous values 1.8-2.0 in the upper 200 m between 71N and 73N. The lowest aragonite saturation of 1.6-

1.7 occurred north of the polar front at 300-400 m depth likely a result of increased CO2 from respiration.

3.3.2 Spatial variability along the northeastern Barents Sea section

In September 2017, carbon chemistry measurements were carried out on water samples collected throughout the water column at eight fixed stations in the northern Barents Sea as part of IMR's fixed hydrographic section (Vardø-N) on the annual ecosystem survey (Figure 41). Favorable sea ice conditions enabled sampling up to 81.5 N. This section captures recirculated Atlantic water from Fram Strait and polar water from the north that are also impacted by sea ice processes (Figure 42). Position, depth and sampling data are displayed in Table 10, Appendix 6.2.

The section across the northern Barents Sea includes Atlantic water from the south and polar water from the north. Salinity in the upper 50 m decreased northwards along the section to low values in the polar water north of 80.3ºN. Lowest salinity is seen north of 80N in water affected by seasonal ice cover (Figure 5, Appendix 6.1). The presence of polar water could also be seen by a northward decreasing temperature gradient at 79ºN that transitioned into cold polar waters. In the upper 50 m the temperature varies from 3 C in the south to -1 C in the north. Recirculated Atlantic water from Fram Strait is a relative warm and saline water mass below 100 m depth in the southern part of the section.

In the surface, both CT and AT decrease northwards to lowest values north of 80ºN where the water column AT and CT was lower at all depths, relative to the southern part of the section. -1 -1 Lowest AT (less than 2200 μmol kg ) and CT (less than 2075 μmol kg ) distinguished the fresh polar water in the upper 50 m with influence of melt water from sea ice. Sea surface pH was highest in the upper 50 m with maximum values of 8.25 at the northern stations. The highest -1 -1 AT values around 2325 μmol kg and high CT of 2200 μmol kg were found at 120-300 m depth within the Atlantic water in the southern part of the section.

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Figure 44. pH and aragonite saturation state along the Barents Sea section in September 2017.

Figur 44. pH og aragonittmetningsgrad fra nordøstlige barentshav i september 2017.

Lowest pH of around 8 was found in the deepest water along the length of the section, especially in the south (Figure 44). Part of the pH variation is driven by temperature changes, since low temperatures are accompanied by higher pH values. The saturation state for aragonite (and calcite, not shown) largely followed the distribution of pH with saturated levels throughout the water column. Maximum values (Ω aragonite  1.8) occurred in the upper layer, typically at the northern and southern end of the section. Lowest saturation states of 1.3 were found in the deepest part of the section, typically below 250 m depth, around 79.5N. This is probably due to increased CO2 resulting from microbial degradation of organic matter and not from anthropogenic ocean acidification.

3.3.3 Seasonal variability in surface water

The stations covered using M/S Norbjørn between Tromsø-Longyearbyen are shown in Figure 45. Position, depth and sampling data are displayed in Table 11, Appendix 6.2. Surface water from 4 m depth was sampled on four cruises in March, May, August and November 2017. The ship’s route varies depending on weather and ice conditions as well as different port calls for cargo deliveries (e.g., Bear Island (~74 N) in March) between cruises.

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Figure 45. Station map for the Barents Sea opening. Samples were taken during 17-20.3 (red ▲), 12-14.5 (blue ●) 4-6.8 (black ▼) and 11-14.11 (green ■). The stations locations varied because of weather or ice conditions and with the delivery to the Bear Island in March.

Figur 45. Stasjoner langs Barentshavsåpningen i året 2017. Toktene ble gjort 17-20.3 (rød ▲), 12-14.5 (blå ●) 4-6.8 (sort ▼) og 11-14.11 (grønn ■). Stasjonene er noe væravhengig som man kan se av spredningen i lengdegrader, samt at skipet i mars hadde en leveranse til Bjørnøya i mars.

The Barents Sea opening is influenced by Atlantic water, Norwegian coastal water and Arctic water (Figure 42). Atlantic Water is the dominant water mass in the open sea between Tromsø and Svalbard, but it is heavily mixed with meltwater from sea ice during the summer. Along the coast of Svalbard, the Atlantic water mixes with Arctic water and meltwater during summer. Norwegian Coastal Current flows along the coast of Norway, and this is mixed with Atlantic water towards the open sea. There is Arctic water in the Bear Island current around the Bear Island. For calculating the seasonal averages of the different parameters, the transect between the coast of Norway to the Isfjord in Svalbard was divided in sections of 69- 72 N (Norwegian coast), 72-74 N (Open Sea S), 74-76 N (Open Sea N) and 76-78 N (Svalbard Coast).

The average salinity for the Norwegian coast reached as low as 34.01 in the summer and as high as 34.45 in the winter. The average salinity for the Svalbard coastal stations reached as low as 33.89 in the summer and as high as 34.90 in winter. The average salinity for the open water stations S and N reached as low as 34.72 and 34.70, respectively, in the summer and as high as 35.02 in winter-spring. The average temperature for the Norwegian coast reached as low as 5.95 C in the winter and as high as 11.15 C in the summer. The average temperature for the Svalbard coastal stations reached as low as 4.01 C in the spring and as high as 8.55 C in summer. The average temperature for the open water stations S and N reached as low as 6.22 and 3.88 C, respectively, in the winter and as high as 10.38 and 10.19 C, respectively, in the summer. Temperature and salinity since 2010 are shown in Figure 46. Temperature during summer 2017 expanded northward in comparison to previous years.

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Figure 46. Eight years of temperature and salinity measurements from the Barents Sea entrance as part of the Tilførselprogrammet and the Ocean Acidification monitoring program. The circles show the measured values, while the interpolated values are shown in the background.

Figur 46. Åtte års målinger i Barentshavsåpningen av temperatur og saltholdighet målt under Tilførselsprogrammet og Havforsuringsovervåkningen. Ringene viser målte verdier, mens interpolerte verdier vises i bakgrunnen.

The pH and aragonite saturation since 2010 are shown in Figure 47. The average pH for the Norwegian coast reached as low as 8.06 in the winter and as high as 8.12 in the summer. The average pH for the Svalbard coastal stations reached as low as 8.05 in the winter and as high as 8.20 in spring. The average pH for the Open water stations S and N reached as low as 8.06 in the winter and as high as 8.14 in the summer.

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Figure 47. In situ pHT and ΩAr from the Barents Sea opening. The circles show the measured and calculated values, while the interpolated values are shown in the background.

Figur 47. In situ pHT og ΩAr fra Barentshavsåpningen. Ringene viser målte og beregnede verdier, mens interpolerte verdier vises i bakgrunnen.

The average aragonite saturation state for the Norwegian coastal waters reached as low as 1.79 in the winter and as high as 2.46 in the summer. The average aragonite saturation for the Svalbard coastal stations reached as low as 1.79 in the autumn and as high as 2.39 in the summer. The average aragonite saturation for the open water stations S and N reached as low as 1.82 and 1.66 in the winter and as high as 2.54 and 2.50 in the summer.

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3.3.4 Trend analysis at selected stations

3.3.4.1 Trend by linear regression

Shown in Figures 48-49 below are the trend analyses using linear regression on average yearly surface winter data from the sections 72-74 N and 74-76 N. The water type can be characterized as Atlantic water or near Atlantic water (S > 35 and T > 4 C).

Figure 48. Linear regression trends in temperature, salinity, pH and aragonite saturation state of winter data in the surface (4 m) at 72-74 N in the Barents Sea Opening.

Figur 48. Lineær regresjon i temperature, saltholdighet, pH og metningsgrad av aragonitt av midlede vinterdata fra overflata (4 m) fra 72-74°N i Barentshavsåpningen.

The seawater salinity and temperature in surface waters of the Barents Sea opening at 72-74 N showed interannual variability associated with seasonal variability in the upper ocean (Figure 48). In general, a freshening of 0,015 yr-1 and cooling of 0,01 C yr-1 was detected, accompanied by a general increase in both pH and Ω aragonite of 0,001 yr-1 and 0,04 yr-1, respectively.

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Figure 49. Linear regression trends in temperature, salinity, pH and aragonite saturation state of winter data in the surface (4 m) at 74-64 N in the Barents Sea Opening.

Figur 49. Lineær regresjon i temperature, saltholdighet, pH og metningsgrad av aragonitt av midlede vinterdata fra overflata (4 m) fra 74-76°N i Barentshavsåpningen.

The seawater salinity and temperature in surface waters of the Barents Sea opening at 74-76 N showed interannual variability associated with seasonal variability in the upper ocean (Figure 49). In general, a cooling of 0.07 C yr-1 was detected, accompanied by an increase in both pH and Ω aragonite of 0.004 yr-1 and 0.04 yr-1, respectively, occurring at faster rates compared to changes in surface waters of the same region at 72-74 N (Figure 48).

The distribution of pH from 2012 to 2017 at 72.8N along the Fugløya-Bjørnøya section shows some year-to-year variation in pH throughout the whole water column, most notably at the start of the time series (Figure 50).

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Figure 50. Six years (2012-2017) of data of pH and aragonite saturation from station 72.8N along the Fugløya- Bjørnøya section.

Figur 50. Seks års (2012-2017) malinger av pH og metningsgrad av aragonitt på stasjonen 72.8N langs Fugløya- Bjørnøya snittet.

In 2013 and 2014, pH values in the upper 100 m were higher 8.10-8.15 compared to rest of the water column at all other years. This is likely due to incursions of high-CT water at this time. The year-to-year distribution of the saturation state for aragonite also showed elevated values in 2013 and 2014 where Ω aragonite > 2 in the surface waters.

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Figure 51. Yearly trend analysis in temperature, CT, pH and aragonite saturation state at 300-400 m deep station 72.8 N along the Fugløya-Blørnøya section.

Figur 51. Årlig trendanalyse av temperature, CT, pH og aragonittmetning ved 300-400 m dyp på stasjonen 72.8N langs Fugløya-Bjørnøya snittet.

The seawater temperature and CT concentrations at 300-400 m depth (deepest station) at 72.8ºN showed interannual variability associated with proximity to the polar front due to the variations in the presence of Atlantic water to the south and Arctic water to the north -1 -1 -1 (Figure 51). In general, a warming of 0.31C yr and decrease in CT of -1.9 µmol kg yr could be detected. This yielded increase in both pH and Ω aragonite of 0.009 yr-1 and 0.06 yr- 1, respectively, which follows a similar pattern but at faster rates compared to surface waters of the Barents Sea opening (Figure 49).

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Figure 52. Five years (2012-2013, 2015-2017) of data of pH and aragonite saturation at the station 79.5 N along the section in the northeast Barents Sea.

Figur 52. Fem års (2012-2013, 2015-2017) malinger av pH og metningsgrad av aragonitt på stasjonen 79.5N langs snittet i nordøstlige Barntshav.

The distribution of pH from 2012 to 2017 at 79.5 N along the northeastern Barents Sea section shows little variation in pH throughout the whole water column throughout the time series (Figure 52). The surface layer was characterised by pH values  8.10 in all years. The year-to-year distribution of the saturation state for aragonite also showed high values (Ω aragonite > 1.7) in the surface layer and a slight decrease in saturation in the deeper part of the water column, below 100 m depth, from 2015 to 2017. This change was associated with a decrease in temperature and salinity at this depth range, perhaps due to the increased presence of polar water masses bringing colder, fresher water to this region.

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Figure 53. Yearly trend analysis in temperature, salinity, pH and aragonite saturation state at 250-300 m depth from the station 79.5 N along the section in the northeastern Barents Sea.

Figur 53. Årlig trendanalyse av temperature, saltholdighet, pH og aragonittmetning på 250-300 m dyp på stasjonen 79.5N langs snittet i nordøstlige Barentshav.

The deepest waters at 250-300 m depth along the northeastern Barents Sea section show changes in seawater temperature and salinity of -0-42 C yr-1 and -0-02, respectively, during the period from 2012 to 2017 (Figure 53). However, pH and the saturation state for aragonite show little trend over time, a slight increase in pH of 0-008 yr-1 was detected, similar to that at this depth range along the Fugløya-Bjørnøya section (Figure 51).

3.3.4.2 Trend of surface pCO2 drivers

The effects of temperature (ΔfCO2temp), biological production (ΔfCO2bio), and the sum of air-sea CO2 gas exchange and mixing of high CO2 waters from below the mixed layer

(calculated as a mass balance; ΔfCO2as-mix) were assessed as drivers of seasonal variation in fCO2, using the methodology described in Chierici et al. (2006) and references therein (see section 3.1.4.2).

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100

50

0

-50

(microatm)

2 -100

fCO -150

fCO2temp fCO bio -200 2 fCO2as+mix

-250

Jul-2012 Jul-2012 Jul-2013 Jul-2014 Jul-2015 Jul-2016 Jul-2017

Jan-2012 Jan-2012 Jan-2013 Jan-2014 Jan-2015 Jan-2016 Jan-2017 Jan-2018

Apr-2012 Apr-2012 Apr-2013 Apr-2014 Apr-2015 Apr-2016 Apr-2017

Oct-2012 Oct-2012 Oct-2013 Oct-2014 Oct-2015 Oct-2016 Oct-2017

Figure 54 Drivers of seasonal ΔfCO2 (µatm) in the Barents Sea opening.

Figur 54. Drivere av sesongvariasjonen av ΔpCO2 (µatm) i Barentshavsåpningen.

Data collected from near 75.3 °N (Atlantic Water mass in the Barents Sea opening) including fCO2 (calculated from CT/AT), sea surface temperature, nitrate concentration at the surface and estimated for below the mixed layer were used for the calculations (Figure 54). The largest negative driver (drawdown) on fCO2 variability was biological production accounting for -150 µatm of the fCO2 change and more during each spring and summer. The increase/decrease in fCO2 due to effect of sea surface temperature was relative modest (~±50 µatm). The combined effect of air-sea interactions and mixing from below the mixed layer was generally similar in magnitude to the effect of temperature change.

3.4 Norwegian Coast

The FerryBox line between Bergen and Kirkenes (M/S Trollfjord) was equipped with sensors for pCO2 in addition to temperature, salinity and chlorophyll-a fluorescence for near continuous measurements. The plotted data (Figure 55) show the temporal and spatial variation in temperature, salinity, photosynthetic biomass (as chlorophyll-a fluorescence) and fCO2. The salinity and fCO2 for a selected trip on 22-28 February 2017 is shown on map to show the route and an example of the variability along the coast. Lower fCO2 was seen to correspond with higher photosynthetic biomass (as chlorophyll-a fluorescence), from the beginning of the spring bloom in March and during summer until august. After august there were very little photosynthetic biomass (chlorophyll-a fluorescence) for the rest of the year and the fCO2 was correspondingly higher.

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Figure 55 Coastal variation in temperature, salinity, chlorophyll-a fluorescence (limited to <5µg/L, indicating the higher values in magenta) and fCO2 (µatm) along the Norwegian coast measured with FerryBox on M/S Trollfjord. At the bottom: salinity and fCO2 from one selected trip 22-28 Feb 2017.

Figur 55. Variasjonen av temperatur, saltholdighet, klorofyll a fluorescens (data vist <5µg/L, magenta indikerer høyere verdier) og fCO2 (µatm) langs norskekysten målt fra FerryBox på M/S Trollfjord. Nederst vises saltholdighet og fCO2 fra en utvalgt tur 22-28 Feb 2017.

3.5 Cold Water Coral Reefs In August 2017, IMR conducted a series of studies of the carbonate chemistry around selected coral reefs commissioned by the Norwegian Environment Agency. The aim was to acquire knowledge about natural variation in physical and chemical processes in cold water coral ecosystems to better understand how these ecosystems respond and adapt to ocean acidification and a warmer sea. Samples for carbon chemistry measurements were taken in the full water column at 3 sites with coral gardens and wall reefs (Hesteneset, Straumsneset, Huglhammaren, Hornaneset) in Hardanger, Hordaland. Position, depth and sampling data are

67 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 displayed in Table 13, Appendix 6.2. Data will be used to get an idea of how the carbon chemistry at the sites varies over time and in space and to study to what extent the carbon chemistry affects where different deep-water coral species can grow.

Figure 56. Variations in temperature, salinity, CT, AT pH and aragonite saturation state in the water column of cold- water coral reefs in Hardanger, Hordaland.

Figur 56. Variasjoner i temperatur, saltholdighet, CT, AT, pH og aragonitt metning i vannkolonnen ved kaldtvannskorallrev i Hardanger, Hordaland.

The water column showed the largest gradients in the upper 100 m in all parameters, which was a consistent feature at the three reef sites (Figure 56). Summertime warming and freshwater inputs (rain and rivers) and biological production reduce CT and AT in the surface layer. This is accompanied by high pH values  8.03 and aragonite saturation states  2.0.

From 100 m depth and below, increasing gradients in CT and AT stabilise at around 2175 µmol kg-1 and 2310 µmol kg-1, respectively. Distributions of pH and saturation states are more variable, however, reaching lowest values of 7.95 and 1.5, respectively, around 150 m depth.

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4. Summary and Recommendations

This monitoring program aims to get an overview of ocean acidification in Norwegian waters and to better understand the variations from season to season and between years. The program started in 2013, and 2017 is the fifth year of measurements, but the report also includes previous acidification measurements, e.g. from the Tilførselsprogrammet.

In the North Sea, the deepest parts of the water column (600 m) in the Skagerrak region showed increased temperatures by 0.31C yr-1 since 2010, which was accompanied by a reduction in pH of 0.013 yr-1 at this depth.

In the Norwegian Sea open ocean, the surface trends in pH and Ar were approximately 0.005 and 0.016 yr-1, respectively, which only differs slightly from what has been estimated previously. The trends at 2000 m depth were 0.003 and 0.008 yr-1, respectively. The saturation horizon for this sea varied around 2000 m depth.

The seawater temperature and aragonite saturation state at 1000 and 1500 m depth at 1ºE along the Svinøy section shows interannual variability related to the variations in the presence of Arctic water at these locations. A slight increasing trend in seawater temperature since 2011 and increased aragonite saturation from 2012 could be identified at these depths. The seawater temperature and salinity at 1200-1500 m depth for the 12.3ºE station along the Gimsøy-NW section shows interannual variability due to the interaction of water masses at these depths. Since 2011, there has been a general increasing temperature and salinity of 0.025 C yr-1 and 0.004, respectively. The pH and the saturation state of aragonite have tended to increase, with a large degree of variability, at these depths from 2011 to 2017.

The Norwegian Sea coastal water is examined in the south (Hardanger) and in the north (Skrova). For the Hardanger area, the time series within the monitoring program is short and trends in pH and Ar are weak. However, when examining a station nearby and including older data, a significant deep water (>600 m) annual decrease of both pH and ΩAr of -0.007 and - 0.02, respectively, is seen.

For the Barents Sea, trends at 300-400 m depth at the 72.8ºN along the Fugløya-Bjønøya -1 -1 -1 section showed a warming of 0.31 C yr and decrease in CT of -1.9 µmol kg yr . Trends in pH and Ω aragonite were increasing at a rate of 0.009 yr-1 and 0.06 yr-1, respectively, which is similar to those detected in the Barents Sea opening.

Cold water coral reefs displayed large gradients in carbonate chemistry in the upper 100 m with lowest pH of 7.95 and aragonite saturation of 1.5 at around 150 m depth. These data complement easier studies carried out on Hola cold-water coral reef in Vesterålen (Chierici et al., 2016) and together will create a good picture of the variability of carbon chemistry parameters (in time and space) in sites where we have dense coral deposits in along the Norwegian coast and in the fjords. Marine research has already described how the composition of different species of coral varies with deep and between different locations. Examining carbon chemistry gradients can give us an initial insight into how our coral reefs are likely to appear in the future.

Data from the water column provides information that can be used to develop scenarios for future CO2 emission concentrations, the ocean's absorption of anthropogenic CO2, and how the depth of the calcium carbonate saturation horizon changes. Even though we begin to get

69 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018 more of an overview of geographic and temporal variation in the ocean acidification parameters (Chierici et al., 2017), and some of the drivers, it is too early to a full extent to determine the individual driving processes of ocean acidification and their regional, seasonal and intermediate variability. This requires a more comprehensive monitoring, i.e. integrated measurements and studies of primary production, ocean physics, and land-sea exchanges. This may be investigated on targeted process research cruises as well as sensors on moorings measuring a set of biogeochemical parameters in addition to pCO2 and pH, such as dissolved oxygen, organic matter, chlorophyll a and particulate. This could be performed and some particularly interesting biological sites such as CWC reefs, spawning sites and others.

Previous studies have shown that inputs of anthropogenic CO2 to the Norwegian Sea are small -1 with a pCO2 increase in surface area of 2-3 μatm year (Skjelvan et al., 2014). This is small compared with the natural background concentration of CO2 (in the range 250-400 μm depending on area and season) and the seasonal variation of CO2 (about 50-150 μm depending on area and season). Thus, long time series are required corresponding to the 20 years that monitoring has been carried out in the Icelandic Sea (Olafsson et al., 2009) in order to be able to say something about the relationship between anthropogenic influence and natural variation. However, this monitoring program provides insight into how the trend may project to certain marine areas. For example, measurements show that the pH in the Norwegian and Lofoten basins decreases rapidly (Skjelvan et al., 2014), and in view of the abundant amounts of cold water corals in the area, it is very important to continue monitoring the ocean acidification trends.

During the last year, the monthly coastal water column carbon measurements have provided more insight into the seasonal changes along the coast, which has been very useful when trying to understand this highly variable area of Norwegian waters. The measurements made in the Norwegian Sea and the Barents Sea in this program provide unique data from an area where there is a great deal of change related to climate, transport of Atlantic waters and decreasing sea ice cover. Especially in the Barents Sea, there are relatively few chemical data from earlier surveys, and therefore, the monitoring program is of international interest. The program also contributes data and knowledge to the International Surface Surveillance Network (Global Network for the Ocean Acidification Observation GOA-ON and ICES Study Group of Ocean Acidification-SGOA).

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5. References

Agnalt, A-L, E.S. Grefsrud, E. Farestveit, M. Larsen & F. Keulder. Deformities in larvae and juvenile European lobster (Homarus gammarus) exposed to lower pH at two different temperatures, Biogeosciences 10 (12): 7883-7895, 2013.

AMAP, Arctic Monitoring and Assessment programme. Arctic Ocean Acidification Assessment: Summary for Policymakers, 2013.

Andersen, S., E.S. Grefsrud & T. Harboe. Effect of increased pCO2 level on early shell development in great scallop (Pecten maximus Lamarck) larvae. Biogeosciences, 10: 6161- 6184, 2013.

Chierici, M., A. Fransson, Nojiri,Y. 2006, Biogeochemical processes as drivers of surface fCO2 in contrasting provinces in the subarctic North Pacific, GBC, 20, doi:10.1029/2004GB002356.

Chierici, M., I. Skjelvan, M. Norli, K.Y. Børsheim, S. K. Lauvset, H.H. Lødemel, K. Sørensen, A.L. King, T. Johannessen. 2017. Overvåking av havforsuring i norske farvann i 2016, Report (in Norwegian), Miljødirektoratet, M-776|2017.

Chierici, M., I. Skjelvan, M. Norli, E. Jones, K.Y. Børsheim, S. K. Lauvset, H.H. Lødemel, K. Sørensen, A.L. King, T. Kutti, A. Renner, A. Omar, T. Johannessen. 2016. Overvåking av havforsuring i norske farvann i 2015, Report (in Norwegian), Miljødirektoratet, M-573|2016.

Dickson, A. G. & F. J. Millero. A comparison of the equilibrium constants for the dissociation of carbonic acid in seawater media. Deep-Sea Res. 34, 1733-1743, 1987.

Dickson, A.G., Standard potential of the reaction: AgCl(s) + ½H2(g) = Ag(s) + HCl(aq), and the standard acidity constant of the ion HSO4 – in synthetic sea water from 273.15 to 318.15 K. J. Chem. Thermodyn. 22: 113–127, 1990.

Dickson, A.G., C.L. Sabine & J.R. Christian (eds.). Guide to Best Practices for Ocean CO2 Measurements. PICES Special Publication 3, IOCCP Report 8, 191 pp, 2007.

Dupont, S & H. Pörtner. A snapshot of ocean acidification research. Marine Biology,160:1765– 1771. DOI 10.1007/s00227-013-2282-9, 2013.

Ingle, S.E., Solubility of calcite in the ocean. Mar. Chem., 3, 1975.

Järnegren, J. & T. Kutti. Lophelia pertusa in Norwegian waters. What have we learned since 2008? - NINA Report 1028. 40 pp. ISSN: 1504-3312,ISBN: 978-82-426-2640-0, 2014.

Johannessen, T., K. Sørensen, K.Y. Børsheim, A. Olsen, E. Yakushev, A. Omar & T.A. Blakseth. Tilførselsprogrammet 2010. Overvåking av forsuring av norske farvann med spesiell fokus på Nordsjøen. Report (in Norwegian), KLIF, TA 2809-2011, 2011.

Le Quéré, C. et al.. Global carbon budget 2016, Earth Syst. Sci. Data 8, 405-448, 2016.

Le Quéré, C. et al.. Global carbon budget 2017, Earth Syst. Sci. Data 10, 605-649, 2018.

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Mehrbach, C., C.H. Culberson, E.J. Hawley, & R M. Pytkowicz. Measurements of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure. Limnol. Oceanogr. 18, 897-907, 1973.

Mortensen, P.B., M.T. Hovland, J.H. Fosså, & D.M. Furevik. Distribution, abundance and size of Lopheliapertusa coral reefs in mid-Norway in relation to seabed characteristics. J. Mar. Biol. Asso. U.K 81, 581-597, 2001.

Mucci, A., The solubility of calcite and aragonite in seawater at various salinities, temperatures and at one atmosphere pressure, Am. J. Sci., 283, 780–799, doi:10.2475/ajs.283.7.780, 1983.

Orr, J. C., V. J. Fabry, O. Aumont et al., Anthropogenic ocean acidification over the twenty- first century and its impact on calcifying organisms. Nature 437, 681-686, 2005.

Olafsson, J., S.R. Olafsdottir, A. Benoit-Cattin, M. Danielsen, T.S. Arnarson & T. Takahashi. Rate of Iceland Sea acidification from time series measurements, Biogeosciences, 6, 2661- 2668, doi:10.5194/bg-6-2661-2009, 2009.

Pierrot, D., E. Lewis & D.W.R. Wallace. MS Excel Program Developed for CO2 System Calculations. ORNL/CDIAC-105a. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee. doi: 10.3334/CDIAC/otg.CO2SYS_XLS_CDIAC105a, 2006.

Skjelvan, I., E. Jeansson, M. Chierici, A. Omar, A. Olsen, S. Lauvset & T. Johannessen. Ocean acidification and uptake of anthropogenic carbon in the Nordic Seas, 1981-2013, Report (in Norwegian), Norwegian Environment Agency, M244-2014, 2014.

Skjelvan, I. & A. M. Omar. Status of knowledge about ocean acidification in fjords at the west coast of Norway, Report (in Norwegian), Norwegian Environment Agency, M426-2015, 2015.

Skjelvan, I., M. Chierici, K. Sørensen, K. Jackson, T. Kutti, H. L. Lødemel, A. King, E. Reggiani, M. Norli, R. Bellerby, E. Yakushev, A. M. Omar. Ocean acidification in western

Norwegian fjords and CO2 variability in Lofoten, Report (in Norwegian), Norwegian Environment Agency, M642-2016, 2016.

Steinacher, M., F. Joos, T.L. Frölicher, G.-K. Plattner & S.C. Doney. Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model. Biogeosciences 6, 515-533, 2009.

Takahashi, T, S.C. Sutherland, R. Wanninkhof et al., Climatological mean and decadal change in the surface ocean pCO2 and net sea-air CO2 flux over the global oceans. Deep-Sea Res. II 56, 554-577, 2009.

Talmange, S. C., & C. J. Gobler. The effects of elevated carbon dioxide concentrations on the metamorphosis, size, and survival of larval hard clams (Mercenariamercenaria), bay scallops (Argopectenirradians) and Eastern oysters (Crassostreavirginia). Limnol. Oceanogr. 54, 2072- 2080, 2009.

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Turley, C.M., J.M. Roberts & J.M. Guinotte. Corals in deep-water: will the unseen hand of ocean acidification destroy cold-water ecosystems? Coral Reefs 26, 445-448, 2007.

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6. Attachments 6.1 Plots

Water column data from Torungen-Hirtshals section.

Figure 1. Temperature, salinity, CT and AT from Torungen-Hirtshals in January 2017.

Figur 1. Temperatur, saltholdighet, CT and AT langs Torungen-Hirtshals snittet i januari 2017.

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Water column data from Svinøy-NW section.

Figure 2. Temperature, salinity, CT and AT from Svinøy-NW in January 2017.

Figur 2. Temperatur, saltholdighet, CT and AT langs Svinøy-NV snittet i januari 2017.

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Water column data from Gimsøy-NW section.

Figure 3. Temperature, salinity, CT and AT from Gimsøy-NW in January 2017.

Figur 3. Temperatur, saltholdighet, CT and AT langs Gimsøy-NV snittet i januari 2017.

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Water column data from Fugløya-Bjørnøya section.

Figure 4. Temperature, salinity, CT and AT from Fugløya-Bjørnøya in February and April 2017.

Figur 4. Temperatur, saltholdighet, CT and AT langs Fugløya-Bjørnøya snittet i februar og april 2017.

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Water column data from Barents Sea section.

Figure 5. Temperature, salinity, CT and AT along the section in the northeast Barents Sea in September 2017.

Figur 5. Temperatur, saltholdighet, CT and AT langs snittet i nordøstlige Barentshav i september 2017.

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Continuous measurements from Station M.

Figure 6. pCO2 in the sea surface at Station M between autumn 2011 and summer 2017. The colour scale indicates temperature.

Figur 6. pCO2 i havoverflata på Stasjon M fra høst 2011 til sommer 2017. Fargeskala viser temperatur.

Figure 7. pH in the sea surface at Station M between autumn 2011 and summer 2017. The colour scale indicates temperature.

Figur 7. pH i havoverflata på Stasjon M fra høst 2011 til sommer 2017. Fargeskala viser temperatur.

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Figure 8. ΩAr in the sea surface at Station M between autumn 2011 and summer 2017. The colour scale indicates temperature.

Figur 8. ΩAr i havoverflata på Stasjon M fra høst 2011 til sommer 2017. Fargeskala viser temperatur.

Figure 9. pCO2 in the sea surface at Station M between autumn 2011 and summer 2017. The colour scale indicates temperature. The area is primarily a sink for atmospheric CO2.

Figur 9. pCO2 i havoverflata på Stasjon M fra høst 2011 til sommer 2017. Fargeskala viser temperatur. Området er et sluk for atmosfærisk CO2 året rundt, bortsett fra korte perioder på vinteren..

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6.2 Data Tables Table 1. Torungen-Hirtshals, January 2017.

Stn Lat Lon Depth T S AT CT pHT Ca Ar N E (m) (C°) (µmol kg-1) (µmol kg-1) 5nm 58,333 8,883 10 6,02 32,91 2299 2161 8,022 2,57 1,62 5nm 58,333 8,883 30 6,92 34,18 2309 2166 8,003 2,60 1,65 5nm 58,333 8,883 50 6,98 34,26 2310 2172 7,989 2,54 1,60 5nm 58,333 8,883 99 7,31 34,60 2311 2171 7,980 2,52 1,59 5nm 58,333 8,883 200 7,78 34,92 2310 2145 8,027 2,79 1,77 15nm 58,200 9,083 10 6,28 33,76 2308 2171 8,005 2,55 1,61 15nm 58,200 9,083 29 6,53 34,00 2302 2168 7,987 2,47 1,56 15nm 58,200 9,083 49 7,90 34,57 * 2159 * * * 15nm 58,200 9,083 99 8,39 35,08 * 2174 * * * 15nm 58,200 9,083 199 8,15 35,15 2333 2181 7,986 2,63 1,68 15nm 58,200 9,083 401 7,13 35,19 2326 2181 7,977 2,42 1,54 20nm 58,133 9,183 10 6,20 33,69 2298 2142 8,056 2,80 1,76 20nm 58,133 9,183 30 6,53 33,96 2308 2158 8,029 2,70 1,70 20nm 58,133 9,183 50 7,17 34,22 2306 2142 8,051 2,88 1,83 20nm 58,133 9,183 100 8,40 35,11 2320 2173 7,973 2,61 1,66 20nm 58,133 9,183 200 7,75 35,17 2323 2172 7,990 2,61 1,66 20nm 58,133 9,183 299 7,39 35,19 2333 2189 7,973 2,47 1,57 20nm 58,133 9,183 399 7,16 35,19 2323 2175 7,984 2,46 1,56 20nm 58,133 9,183 600 6,92 35,19 2344 2210 7,941 2,19 1,40 30nm 58,000 9,350 10 5,91 33,50 2301 2158 8,028 2,61 1,65 30nm 58,000 9,350 29 6,88 34,06 2311 2145 8,063 2,93 1,86 30nm 58,000 9,350 49 8,29 34,84 2314 2144 8,038 2,96 1,88 30nm 58,000 9,350 100 8,77 35,08 2313 2143 8,026 2,93 1,86 30nm 58,000 9,350 199 8,05 35,15 2323 2170 7,989 2,63 1,67 30nm 58,000 9,350 401 7,39 35,19 2341 2190 7,985 2,50 1,59 Ærøydypet 58,400 8,767 9 6,63 33,77 2304 2146 8,051 2,83 1,78 Ærøydypet 58,400 8,767 30 7,13 34,09 2309 2152 8,036 2,80 1,77 Ærøydypet 58,400 8,767 51 6,90 34,09 2315 2154 8,048 2,84 1,80 Ærøydypet 58,400 8,767 101 7,07 34,19 2305 2146 8,040 2,79 1,77 Ærøydypet 58,400 8,767 127 8,19 34,93 2333 2197 7,949 2,46 1,56

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Table 2. Arendal coastal station, January-November 2017.

Date Lat Lon Depth T S AT CT pHT Ca Ar NO3 PO4 SiOH4 N E (m) (C°) (µmol kg-1) (µmol kg-1) (µmol/kg) (µmol/kg) (µmol/kg)

21.1. 58,230 8,500 2 5,69 32,60 2200 2060 8,045 2,53 1,59 4,9 0,46 4,6 21.1. 58,230 8,500 5 5,82 32,73 2282 2135 8,053 2,69 1,69 5,0 0,46 3,9 21.1. 58,230 8,500 10 6,02 33,06 2304 2170 8,010 2,52 1,59 4,9 0,45 3,7 21.1. 58,230 8,500 20 6,57 33,56 2291 2139 8,042 2,74 1,73 4,7 0,43 3,5 21.1. 58,230 8,500 30 6,69 33,97 2299 2141 8,049 2,81 1,78 5,1 0,46 3,2 21.1. 58,230 8,500 50 6,94 34,18 2304 2144 8,047 2,83 1,79 5,1 0,45 3,2 21.1. 58,230 8,500 76 6,99 34,26 2308 2146 8,048 2,84 1,80 5,1 0,45 3,2 3.2. 58,230 8,500 0 3,52 27,76 2175 2064 8,066 2,21 1,37 5,2 0,49 6,7 3.2. 58,230 8,500 4 3,53 28,03 2172 2062 8,058 2,19 1,35 5,2 0,48 6,7 3.2. 58,230 8,500 10 3,70 28,42 2211 2087 8,087 2,40 1,49 5,1 0,50 6,3 3.2. 58,230 8,500 21 4,95 31,28 2263 2127 8,058 2,54 1,59 5,2 0,49 5,7 3.2. 58,230 8,500 30 5,89 32,85 2290 2140 8,055 2,71 1,71 5,2 0,48 4,3 3.2. 58,230 8,500 51 6,37 33,94 2304 2147 8,049 2,78 1,76 5,0 0,47 3,3 3.2. 58,230 8,500 76 6,80 34,33 2329 2165 8,051 2,87 1,82 5,0 0,49 3,4 10.3. 58,230 8,500 3 3,80 29,91 2100 1990 8,035 2,11 1,31 2,3 0,27 0,8 10.3. 58,230 8,500 6 3,97 30,44 2269 2107 8,154 2,95 1,84 2,2 0,26 0,5 10.3. 58,230 8,500 10 4,37 31,86 2260 2098 8,129 2,90 1,82 2,3 0,28 0,4 10.3. 58,230 8,500 20 4,68 32,57 2280 2122 8,101 2,82 1,77 3,0 0,35 0,5 10.3. 58,230 8,500 30 5,18 32,99 2286 2129 8,083 2,80 1,76 3,7 0,37 0,9 10.3. 58,230 8,500 51 6,54 34,24 2303 2152 8,029 2,70 1,71 6,9 0,56 4,3 10.3. 58,230 8,500 77 6,99 34,55 2307 2149 8,035 2,78 1,76 7,1 0,57 4,1 25.4. 58,230 8,500 3 6,73 30,26 2221 2058 8,120 2,97 1,86 0,2 0,12 0,9 25.4. 58,230 8,500 7 6,73 30,25 2232 2059 8,143 3,12 1,96 0,1 0,10 0,9 25.4. 58,230 8,500 11 6,82 30,97 2267 2090 8,135 3,17 1,99 0,2 0,15 0,8 25.4. 58,230 8,500 20 6,74 31,99 2280 2111 8,103 3,03 1,90 1,0 0,24 1,5 25.4. 58,230 8,500 30 6,57 32,51 2290 2119 8,102 3,03 1,91 1,4 0,29 1,8 25.4. 58,230 8,500 51 6,39 33,28 2303 2142 8,068 2,86 1,80 2,8 0,38 2,7 25.4. 58,230 8,500 76 6,58 34,57 2339 2189 8,017 2,68 1,70 5,2 0,52 3,6 12.5. 58,230 8,500 2 8,63 27,63 2168 2027 8,073 2,70 1,68 0,1 0,12 1,6 12.5. 58,230 8,500 6 8,62 27,63 2166 2021 8,085 2,75 1,71 0,3 0,17 1,3 12.5. 58,230 8,500 12 8,68 27,78 2160 2016 8,082 2,74 1,71 0,1 0,09 1,5 12.5. 58,230 8,500 20 8,73 30,09 2250 2081 8,100 3,09 1,94 0,2 0,11 1,4 12.5. 58,230 8,500 30 7,36 33,13 2291 2125 8,069 2,95 1,86 0,4 0,19 1,0 12.5. 58,230 8,500 50 7,17 34,14 2276 2134 7,999 2,56 1,62 2,7 0,38 2,2 12.5. 58,230 8,500 76 7,12 34,91 2312 2150 8,037 2,83 1,79 5,6 0,50 3,0 11.6. 58,230 8,500 0 12,66 26,32 1917 1772 8,076 2,70 1,68 1,2 0,07 5,1 11.6. 58,230 8,500 3 12,58 29,55 2155 1985 8,064 3,13 1,97 0,2 0,06 1,9 11.6. 58,230 8,500 6 12,38 30,56 2241 2069 8,046 3,17 2,00 0,1 0,08 1,4 11.6. 58,230 8,500 10 11,78 31,69 2256 2084 8,039 3,13 1,99 0,1 0,09 1,4 11.6. 58,230 8,500 19 11,32 32,53 2293 2122 8,028 3,10 1,97 0,2 0,11 1,6 11.6. 58,230 8,500 29 10,61 33,38 2302 2131 8,026 3,06 1,94 0,3 0,13 1,7 11.6. 58,230 8,500 49 9,02 34,26 2306 2138 8,032 2,97 1,88 1,0 0,27 2,4 11.6. 58,230 8,500 75 8,59 34,43 2307 2142 8,029 2,90 1,84 1,5 0,31 2,5 1.7. 58,230 8,500 1 16,23 29,06 2153 2026 7,901 2,54 1,61 0,1 0,04 1,1 1.7. 58,230 8,500 5 15,78 29,06 2171 1986 8,054 3,42 2,17 0,2 0,10 1,7 1.7. 58,230 8,500 10 15,56 29,79 2176 1979 8,074 3,57 2,27 0,0 0,10 1,1

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1.7. 58,230 8,500 19 15,21 30,50 2211 2014 8,066 3,56 2,27 0,1 0,09 1,0 1.7. 58,230 8,500 29 12,78 32,61 2306 2132 8,008 3,16 2,01 0,5 0,21 1,9 1.7. 58,230 8,500 50 10,49 34,38 2311 2141 8,011 3,00 1,91 1,1 0,28 2,1 1.7. 58,230 8,500 76 8,91 34,64 2318 2158 8,008 2,84 1,80 1,0 0,33 2,0 10.8. 58,230 8,500 3 17,13 28,64 2159 1970 8,050 3,51 2,23 0,0 0,10 1,4 10.8. 58,230 8,500 6 16,80 29,28 2189 1991 8,063 3,64 2,31 0,0 0,09 1,3 10.8. 58,230 8,500 10 16,67 31,39 2244 2031 8,061 3,81 2,44 0,1 0,08 0,7 10.8. 58,230 8,500 21 16,00 32,99 2284 2075 8,034 3,68 2,36 0,3 0,11 0,9 10.8. 58,230 8,500 32 15,76 33,98 2306 2104 8,010 3,57 2,29 0,2 0,15 1,4 10.8. 58,230 8,500 50 14,86 34,23 2304 2109 8,003 3,42 2,19 0,3 0,19 1,4 10.8. 58,230 8,500 76 13,48 34,48 2308 2119 8,006 3,29 2,10 0,5 0,22 1,5 14.9. 58,230 8,500 2 15,55 25,48 2071 1900 8,092 3,28 2,05 0,2 0,04 1,0 14.9. 58,230 8,500 6 15,61 25,61 2102 1938 8,065 3,18 1,99 0,1 0,05 1,0 14.9. 58,230 8,500 11 16,17 27,69 2193 2010 8,060 3,46 2,19 0,5 0,05 1,6 14.9. 58,230 8,500 22 16,43 30,95 2238 2051 8,015 3,43 2,19 1,1 0,16 2,1 14.9. 58,230 8,500 32 16,20 32,54 2284 2102 7,978 3,30 2,12 2,0 0,23 2,6 14.9. 58,230 8,500 50 16,02 33,11 2292 2116 7,959 3,19 2,05 1,9 0,19 2,6 14.9. 58,230 8,500 77 14,78 34,27 2305 2122 7,977 3,23 2,07 1,7 0,24 2,7 7.10. 58,230 8,500 2 13,61 23,80 2083 1929 8,100 3,04 1,88 0,1 0,17 1,7 7.10. 58,230 8,500 5 14,10 24,77 2099 1947 8,071 2,99 1,86 0,2 0,20 2,3 7.10. 58,230 8,500 9 14,10 25,13 2147 1988 8,077 3,12 1,94 0,5 0,23 2,3 7.10. 58,230 8,500 21 15,05 30,18 2243 2064 8,025 3,31 2,10 0,8 0,24 2,8 7.10. 58,230 8,500 31 15,26 32,84 2301 2105 8,019 3,51 2,25 0,7 0,22 2,5 7.10. 58,230 8,500 48 15,72 33,88 2324 2115 8,022 3,66 2,35 0,2 0,22 2,8 7.10. 58,230 8,500 76 14,51 34,43 2320 2123 8,007 3,42 2,20 1,5 0,25 3,1 17.11. 58,230 8,500 3 12,49 33,82 2291 2109 8,018 3,23 2,06 2,3 0,35 3,3 17.11. 58,230 8,500 6 12,49 33,82 2302 2113 8,034 3,35 2,13 2,2 0,36 3,2 17.11. 58,230 8,500 11 12,45 33,88 2303 2122 8,014 3,21 2,05 2,0 0,35 3,1 17.11. 58,230 8,500 21 12,54 34,33 2315 2136 8,001 3,17 2,03 2,2 0,36 3,0 17.11. 58,230 8,500 32 11,57 34,39 2303 2122 8,021 3,18 2,03 2,3 0,34 2,5 17.11. 58,230 8,500 49 10,93 34,40 2295 2120 8,017 3,07 1,95 2,3 0,31 1,9 17.11. 58,230 8,500 75 10,67 34,72 2308 2148 7,980 2,84 1,81 5,0 0,46 3,6

83 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Table 3. Langenuen, 2017

Date Stn Lat Lon Depth S T AT CT pHT Ca Ar NO3 PO4 SiOH4 N E (m) (C°) (µmol kg-1) (µmol kg-1) (µmol/kg) (µmol/kg) (µmol/kg) 6/7 2 59.83 5.57 206 35.15 8.26 2327.2 2151.3 8.042 2.95 1.88 9.94 0.74 5.18 6/7 2 59.83 5.57 104 34.78 8.22 2318.7 2151.4 8.031 2.90 1.84 9.37 0.71 4.98 6/7 2 59.83 5.57 53 34.22 8.19 2304.8 2206.2 7.86 2.02 1.28 7.66 0.62 3.68 6/7 2 59.83 5.57 33 33.18 8.51 2281.9 2106.9 8.073 3.08 1.95 3.76 0.41 1.99 6/7 2 59.83 5.57 11 30.84 11.36 2168.4 1994.7 8.071 3.12 1.97 0.4 0.1 0.6 6/7 2 59.83 5.57 5 27.07 13.28 1869.7 1700.0 8.129 3.01 1.89 0.4 0.05 0.6 8/9 2 59.83 5.55 201 35.05 7.85 2316.6 2166.8 7.987 2.59 1.65 10.36 0.77 5.93 8/9 2 59.83 5.55 151 34.91 7.97 2312.3 2172.9 7.963 2.48 1.58 10.84 0.84 6.44 8/9 2 59.83 5.55 103 34.72 8.16 2308.0 2172.0 7.955 2.47 1.57 10.26 0.82 6.01 8/9 2 59.83 5.55 82 34.33 8.51 2296.6 2151.4 7.981 2.61 1.66 8.24 0.65 4.61 8/9 2 59.83 5.55 62 33.91 9.60 2279.8 2132.1 7.978 2.67 1.70 5.05 0.44 2.67 8/9 2 59.83 5.55 52 33.37 10.80 2271.0 2112.3 7.995 2.85 1.81 3.75 0.35 1.92 8/9 2 59.83 5.55 41 32.97 11.91 2251.9 2087.0 8.001 2.96 1.88 1.73 0.22 1.08 8/9 2 59.83 5.55 31 32.38 13.71 2238.1 2057.9 8.02 3.22 2.05 0.69 0.15 0.6 8/9 2 59.83 5.55 21 32.21 15.27 2228.6 2035.5 8.029 3.44 2.20 0.4 0.06 0.6 8/9 2 59.83 5.55 11 30.96 15.69 2205.1 * * * * 0.4 0.06 0.6 8/9 2 59.83 5.55 6 26.57 15.84 1920.2 1744.1 8.105 3.20 2.01 0.4 0.05 0.6 9/6 2 59.83 5.56 195 34.97 8.16 2316.9 2170.1 7.976 2.56 1.63 10.43 0.78 6.02 9/6 2 59.83 5.56 154 34.89 8.26 2306.1 2161.6 7.972 2.55 1.62 10.56 0.79 6.39 9/6 2 59.83 5.56 103 34.47 9.17 2307.1 2165.6 7.957 2.56 1.63 8.89 0.71 5.29 9/6 2 59.83 5.56 82 34.19 9.97 2299.2 2151.0 7.967 2.67 1.70 7.43 0.60 4.29 9/6 2 59.83 5.56 62 33.69 12.13 2285.6 2124.0 7.976 2.90 1.85 3.96 0.35 2.37 9/6 2 59.83 5.56 51 33.54 14.13 2292.9 2112.5 7.991 3.21 2.05 2.36 0.23 1.68 9/6 2 59.83 5.56 41 33.31 14.90 2280.0 2097.2 7.99 3.26 2.09 1.78 0.19 1.44 9/6 2 59.83 5.56 31 32.17 14.92 2239.4 2061.6 7.998 3.21 2.05 1.56 0.17 0.62 9/6 2 59.83 5.56 16 30.43 15.52 2161.3 1978.7 8.035 3.31 2.11 0.43 0.07 0.58 9/6 2 59.83 5.56 5 25.57 15.73 1857.1 1687.4 8.116 3.10 1.94 0.00 0.09 0.49 10/4 2 59.83 5.56 200 35.01 8.06 2317.0 2172.8 7.97 2.52 1.60 10.45 0.77 5.72 10/4 2 59.83 5.56 150 34.92 8.29 2304.9 2176.9 7.928 2.33 1.48 10.73 0.83 5.93 10/4 2 59.83 5.56 100 34.64 8.95 2280.5 2137.6 7.966 2.56 1.63 6.89 0.55 3.21 10/4 2 59.83 5.56 80 34.43 9.68 2262.5 2105.5 7.996 2.76 1.76 4.40 0.35 2.11 10/4 2 59.83 5.56 60 34.05 11.54 2250.7 2078.6 8.01 3.01 1.92 2.79 0.20 1.32 10/4 2 59.83 5.56 50 33.88 12.69 2244.0 2065.6 8.011 3.12 1.99 2.35 0.17 1.27 10/4 2 59.83 5.56 40 33.48 13.36 2208.0 2033.1 8.002 3.08 1.96 2.20 0.15 1.07 10/4 2 59.83 5.56 30 32.55 13.54 2197.1 2019.0 8.021 3.16 2.01 1.45 0.11 0.61 10/4 2 59.83 5.56 20 31.29 14.10 2162.9 1982.8 8.038 3.22 2.05 0.62 0.08 0.54 10/4 2 59.83 5.56 10 27.77 13.82 2150.3 1967.7 8.1 3.39 2.13 0.49 0.07 0.14 10/4 2 59.83 5.56 5 28.32 13.44 2136.3 1956.3 8.094 3.32 2.09 0.46 0.07 0.22 11/6 2 59.83 5.56 194 35.05 7.96 2319.7 2167.2 7.982 2.58 1.64 9.33 4.89 0.72 11/6 2 59.83 5.56 154 34.94 8.32 2320.2 2165.7 7.985 2.63 1.67 8.77 4.81 0.69 11/6 2 59.83 5.56 102 34.81 8.73 2314.3 2165.6 7.967 2.59 1.64 8.51 4.95 0.68 11/6 2 59.83 5.56 82 34.67 9.39 2308.4 2156.0 7.971 2.66 1.69 7.51 4.36 0.61 11/6 2 59.83 5.56 62 34.41 10.95 2301.8 2136.6 7.986 2.89 1.84 5.17 3.09 0.45 11/6 2 59.83 5.56 52 34.21 11.25 2293.8 2124.7 7.995 2.95 1.88 4.62 2.80 0.41 11/6 2 59.83 5.56 42 33.64 11.83 2272.3 2106.3 7.99 2.93 1.87 4.12 2.32 0.36 11/6 2 59.83 5.56 31 32.93 12.17 2251.4 2085.6 7.997 2.96 1.88 3.81 1.81 0.32

84 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

11/6 2 59.83 5.56 19 32.15 12.68 2236.1 2073.7 7.993 2.94 1.87 3.50 1.65 0.29 11/6 2 59.83 5.56 8 29.96 11.91 2058.6 1913.6 8.011 2.64 1.66 2.54 1.55 0.15 11/6 2 59.83 5.56 3 28.32 11.15 1991.1 1854.0 8.031 2.51 1.58 2.16 1.68 0.12

85 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Table 4. Hardangerfjord, 2017.

Date Stn Lat Lon Depth S T AT CT pHT Ca Ar NO3 PO4 SiOH4 N E (m) (C°) (µmol kg-1) (µmol kg-1) (µmol/kg) (µmol/kg) (µmol/kg)

6/7 1 59.74 5.5 333 35.16 8.19 2316.0 2154.2 8.006 2.68 1.71 10.28 0.76 5.5 6/7 1 59.74 5.5 99 34.79 8.28 2315.7 2156.1 8.012 2.79 1.77 10.12 0.76 5.5 6/7 1 59.74 5.5 47 34.05 8.25 2298.4 2151.6 7.993 2.66 1.68 9.02 0.71 4.7 6/7 1 59.74 5.5 27 33 8.00 2269.4 2116.6 8.03 2.76 1.74 4.42 0.49 2 6/7 1 59.74 5.5 8 28.98 11.65 2151.7 1966.5 8.122 3.36 2.11 0.4 0.1 0.8 6/7 1 59.74 5.5 4 26.69 12.91 1919.2 1743.4 8.148 3.15 1.97 0.4 0.15 0.7 8/9 1 59.74 5.5 339 35.08 7.88 2316.4 2166.2 7.982 2.52 1.61 10.52 0.77 6.2 8/9 1 59.74 5.5 205 35 7.94 2315.5 2173.6 7.966 2.49 1.58 10.85 0.82 6.5 8/9 1 59.74 5.5 103 34.58 8.38 * * * * * * 0.17 1 8/9 1 59.74 5.5 82 34.39 8.37 2298.8 2155.5 7.977 2.58 1.64 8.6 0.67 4.7 8/9 1 59.74 5.5 62 33.91 9.19 2286.0 2148.5 7.958 2.53 1.61 6.2 0.52 3.3 8/9 1 59.74 5.5 52 33.45 9.97 2273.8 2127.0 7.977 2.67 1.70 5.26 0.45 2.8 8/9 1 59.74 5.5 41 33.01 11.31 2253.6 2095.4 7.993 2.86 1.82 2.74 0.28 1.4 8/9 1 59.74 5.5 31 32.83 12.46 2236.5 * * * * 1.33 0.19 0.8 8/9 1 59.74 5.5 21 32.24 14.50 2218.4 2034.9 8.02 3.28 2.09 0.4 0.08 0.6 8/9 1 59.74 5.5 11 31.54 15.82 2199.5 1999.9 8.049 3.56 2.27 0.4 0.05 0.6 8/9 1 59.74 5.5 6 28.25 15.84 1882.0 1707.9 8.081 3.07 1.94 0.4 0.06 0.6 9/6 1 59.74 5.5 337 35.06 7.92 2334.1 2168.3 8.018 2.74 1.74 10.12 0.78 5.90 9/6 1 59.74 5.5 205 35.01 7.95 2322.5 * * * * 10.91 0.81 6.14 9/6 1 59.74 5.5 103 34.47 8.52 2303.9 2162.8 7.967 2.54 1.61 9.22 0.73 5.36 9/6 1 59.74 5.5 82 34.03 9.99 2295.8 2148.9 7.966 2.66 1.69 7.39 0.61 4.42 9/6 1 59.74 5.5 62 33.92 13.10 2296.4 2143.0 7.937 2.80 1.79 3.16 0.30 1.93 9/6 1 59.74 5.5 52 33.37 13.12 2286.4 2114.6 7.99 3.08 1.96 3.10 0.28 1.62 9/6 1 59.74 5.5 41 32.68 13.37 2248.9 2080.1 7.992 3.04 1.94 2.60 0.23 1.42 9/6 1 59.74 5.5 31 32 14.09 2228.9 2058.1 7.998 3.10 1.97 2.14 0.21 1.16 9/6 1 59.74 5.5 20 31.03 15.21 2177.1 1999.7 8.017 3.21 2.05 1.08 0.12 0.76 9/6 1 59.74 5.5 10 29.98 15.74 2119.6 1922.2 8.078 3.53 2.25 0.00 0.06 0.56 9/6 1 59.74 5.5 5 29.18 15.62 2091.3 1899.8 8.082 3.46 2.19 0.09 0.07 0.49 10/4 1 59.74 5.5 330 35.05 7.91 2316.4 2168.0 7.978 2.51 1.60 10.16 0.78 6.00 10/4 1 59.74 5.5 200 35.02 7.96 2314.3 2171.5 7.968 2.50 1.59 10.85 0.83 6.63 10/4 1 59.74 5.5 100 34.67 8.51 2297.6 2157.5 7.962 2.52 1.60 9.14 0.70 5.08 10/4 1 59.74 5.5 80 34.53 9.47 2281.0 2128.4 7.984 2.71 1.72 6.22 0.51 3.64 10/4 1 59.74 5.5 60 34.14 11.62 2269.9 2100.5 7.999 2.98 1.90 3.91 0.31 2.46 10/4 1 59.74 5.5 50 33.74 11.93 2260.1 2084.9 8.015 3.08 1.96 3.19 0.25 2.13 10/4 1 59.74 5.5 40 33.06 12.49 2244.1 2070.8 8.013 3.08 1.96 0.35 0.05 1.55 10/4 1 59.74 5.5 30 32.6 12.98 2199.8 2047.0 7.966 2.78 1.77 2.94 0.20 1.14 10/4 1 59.74 5.5 20 31.58 13.72 2155.1 1979.6 8.03 3.13 1.99 0.43 0.08 0.71 10/4 1 59.74 5.5 10 30.01 14.04 2117.3 1939.6 8.057 3.21 2.03 0.15 0.08 0.69 10/4 1 59.74 5.5 5 28.89 13.47 2115.2 1940.8 8.074 3.19 2.01 0.30 0.08 0.59

11/6 1 59.74 5.5 325 35.04 7.90 2321.8 2174.6 7.962 2.43 1.55 9.57 5.74 0.76 11/6 1 59.74 5.5 204 35.02 7.98 2318.8 2173.2 7.963 2.47 1.57 9.48 5.57 0.77 11/6 1 59.74 5.5 102 34.86 8.51 2314.9 2167.0 7.968 2.57 1.63 8.73 5.08 0.70 11/6 1 59.74 5.5 79 35.02 8.94 2313.2 2162.1 7.969 2.63 1.67 7.94 4.68 0.65 11/6 1 59.74 5.5 59 34.36 10.14 2303.2 2147.2 7.974 2.74 1.74 6.98 4.13 0.57 11/6 1 59.74 5.5 49 34.1 10.74 2286.7 2125.6 7.985 2.83 1.80 5.48 3.27 0.46 11/6 1 59.74 5.5 39 33.44 11.60 2279.4 2113.2 7.994 2.94 1.87 4.86 2.88 0.41

86 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

11/6 1 59.74 5.5 30 33.2 11.86 2261.4 2095.8 7.995 2.94 1.87 4.28 2.37 0.35 11/6 1 59.74 5.5 20 32.13 12.24 2243.4 2079.9 8.001 2.95 1.87 3.96 2.08 0.32 11/6 1 59.74 5.5 10 30.04 12.35 2059.2 1914.6 8.001 2.63 1.66 2.59 1.66 0.17 11/6 1 59.74 5.5 5 28.59 11.31 1976.1 1843.4 8.013 2.43 1.52 2.42 1.89 0.13

87 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Table 5. Svinøy-NW, February and May 2017.

Stn Date Lat Lon Depth T S AT CT pHT Ca Ar N E (m) (C°) (µmol kg-1) (µmol kg-1) 2 8.2. 62,485 4,946 187 8,90 35,14 2327 2158 8,017 2,88 1,83 2 8.2. 62,485 4,946 150 8,85 35,05 2331 2164 8,013 2,87 1,82 2 8.2. 62,485 4,946 100 8,27 34,76 2347 2179 8,030 2,93 1,86 2 8.2. 62,485 4,946 73 8,52 34,89 2335 2161 8,040 3,02 1,92 2 8.2. 62,485 4,946 49 7,84 34,57 2319 2151 8,044 2,94 1,87 2 8.2. 62,485 4,946 19 7,62 34,50 2314 2143 8,056 3,00 1,90 2 8.2. 62,485 4,946 9 7,62 34,49 2314 2146 8,049 2,96 1,87 6 8.2. 62,838 4,176 605 6,39 35,09 2336 2153 8,070 2,78 1,77 6 8.2. 62,838 4,176 502 7,73 35,12 2342 2169 8,029 2,73 1,74 6 8.2. 62,838 4,176 302 9,03 35,25 2344 2168 8,023 2,91 1,86 6 8.2. 62,838 4,176 203 9,02 35,25 2342 2166 8,027 2,96 1,89 6 8.2. 62,838 4,176 152 9,02 35,25 2346 2167 8,037 3,05 1,94 6 8.2. 62,838 4,176 76 9,00 35,25 2333 2155 8,036 3,05 1,94 6 8.2. 62,838 4,176 50 9,00 35,25 2340 2167 8,027 3,02 1,92 6 8.2. 62,838 4,176 30 9,00 35,25 2338 2159 8,041 3,11 1,97 6 8.2. 62,838 4,176 10 9,00 35,25 2341 2166 8,033 3,07 1,95 6 8.2. 62,838 4,176 4 9,00 35,25 2345 2172 8,026 3,04 1,93 9 8.2. 64,074 3,657 954 -0,78 34,91 2316 2177 8,069 1,98 1,26 9 8.2. 64,074 3,657 800 -0,68 34,91 2314 2178 8,067 2,02 1,28 9 8.2. 64,074 3,657 500 4,73 34,98 2322 2172 8,027 2,41 1,53 9 8.2. 64,074 3,657 400 7,46 35,09 2324 2158 8,026 2,70 1,72 9 8.2. 64,074 3,657 200 8,98 35,25 2330 2152 8,033 2,98 1,90 9 8.2. 64,074 3,657 100 8,98 35,25 2334 2150 8,051 3,13 1,99 9 8.2. 64,074 3,657 50 8,97 35,25 2332 2154 8,040 3,09 1,96 9 8.2. 64,074 3,657 30 8,97 35,25 2350 2171 8,041 3,12 1,99 9 8.2. 64,074 3,657 11 8,95 35,25 2340 2168 8,026 3,02 1,92 11 8.2. 63,310 3,133 1049 -0,80 34,91 2335 2172 8,126 2,21 1,41 11 8.2. 63,310 3,133 800 -0,62 34,91 2321 2182 8,075 2,07 1,31 11 8.2. 63,310 3,133 500 0,69 34,91 2312 2180 8,047 2,14 1,35 11 8.2. 63,310 3,133 398 3,19 34,95 2316 2171 8,043 2,37 1,50 11 8.2. 63,310 3,133 151 7,81 34,13 2342 2175 8,042 2,90 1,84 11 8.2. 63,310 3,133 74 7,80 35,13 2324 2151 8,048 2,98 1,89 11 8.2. 63,310 3,133 52 7,80 35,13 2337 2164 8,046 3,00 1,90 11 8.2. 63,310 3,133 30 7,80 35,13 2326 2155 8,045 2,99 1,89 11 8.2. 63,310 3,133 12 7,80 35,13 2333 2165 8,038 2,96 1,88 13 9.2. 63,663 2,338 1415 -0,78 34,91 2323 2162 8,107 2,00 1,28 13 9.2. 63,663 2,338 1002 -0,57 34,91 2316 2149 8,137 2,27 1,45 13 9.2. 63,663 2,338 800 -0,33 34,90 2311 2175 8,062 2,03 1,29 13 9.2. 63,663 2,338 501 3,52 34,97 2320 2168 8,051 2,41 1,53 13 9.2. 63,663 2,338 200 7,93 34,14 2323 2150 8,053 2,94 1,86 13 9.2. 63,663 2,338 100 7,92 35,14 2339 2163 8,049 3,01 1,91 13 9.2. 63,663 2,338 51 7,93 35,14 2350 2175 8,046 3,03 1,92 13 9.2. 63,663 2,338 30 7,92 35,14 2336 2165 8,040 2,98 1,89 13 9.2. 63,663 2,338 9 7,92 35,13 2351 2180 8,040 3,01 1,91 15 9.2. 64,135 1,262 1396 -0,63 34,91 2317 2171 8,068 1,86 1,19 15 9.2. 64,135 1,262 1001 -0,42 34,91 2320 2153 8,135 2,28 1,45

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15 9.2. 64,135 1,262 801 -0,22 34,91 2319 2153 8,136 2,38 1,51 15 9.2. 64,135 1,262 502 1,24 34,92 2313 2179 8,042 2,17 1,37 15 9.2. 64,135 1,262 200 6,58 35,01 2326 2153 8,062 2,89 1,83 15 9.2. 64,135 1,262 102 7,05 35,06 2330 2160 8,049 2,91 1,84 15 9.2. 64,135 1,262 49 7,55 35,10 2325 2166 8,018 2,79 1,77 15 9.2. 64,135 1,262 30 7,55 35,11 2322 2151 8,048 2,97 1,88 117 6.5. 64,134 1,261 2421 -0,78 34,92 2317 2170 8,032 1,48 0,96 117 6.5. 64,134 1,261 2000 -0,73 34,92 2312 2166 8,045 1,62 1,04 117 6.5. 64,134 1,261 1500 -0,64 34,92 2316 2154 8,106 1,98 1,27 117 6.5. 64,134 1,261 1000 -0,46 34,92 2311 2167 8,075 2,01 1,28 117 6.5. 64,134 1,261 800 -0,32 34,92 2308 2173 8,057 2,01 1,27 117 6.5. 64,134 1,261 500 0,22 34,91 2334 2166 8,144 2,59 1,64 117 6.5. 64,134 1,261 400 0,78 34,92 2324 2165 8,119 2,54 1,60 117 6.5. 64,134 1,261 200 4,01 34,94 2314 2162 8,056 2,59 1,64 117 6.5. 64,134 1,261 100 5,91 35,00 2318 2146 8,077 2,94 1,86 117 6.5. 64,134 1,261 50 6,11 35,01 2323 2157 8,060 2,88 1,82 117 6.5. 64,134 1,261 29 6,45 35,04 2321 2152 8,063 2,94 1,86 117 6.5. 64,134 1,261 11 7,01 35,08 2333 2137 8,115 3,35 2,12

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Table 6. Station M, 2017.

Stn Lat Lon Depth Date S T AT CT pHT Ca Ar (m) (C°) (µmol kg-1) (µmol kg-1) N E 18 66.00 2.00 1367 2/10 34.91 -0.66 2301.3 2165.6 8.043 1.76 1.12 18 66.00 2.00 1184 2/10 34.91 -0.58 2306.8 2169.7 8.053 1.85 1.18 18 66.00 2.00 988 2/10 34.91 -0.46 2301.8 2170.1 8.045 1.88 1.20 18 66.00 2.00 793 2/10 34.91 -0.23 2303.3 2176.7 8.035 1.92 1.22 18 66.00 2.00 496 2/10 34.92 1.39 2304.3 2173.3 8.032 2.13 1.35 18 66.00 2.00 395 2/10 34.97 3.19 2308.0 2165.2 8.038 2.34 1.48 18 66.00 2.00 299 2/10 35.06 5.54 2315.0 2160.8 8.031 2.57 1.63 18 66.00 2.00 197 2/10 35.09 7.16 2315.9 2149.8 8.038 2.80 1.78 18 66.00 2.00 97 2/10 35.11 7.38 2315.8 2147.7 8.043 2.89 1.83 18 66.00 2.00 51 2/10 35.12 7.60 2316.9 2147.3 8.045 2.94 1.87 18 66.00 2.00 30 2/10 35.13 7.67 2316.8 2149.7 8.038 2.92 1.85 18 66.00 2.00 11 2/10 35.13 7.66 2315.8 2149.1 8.038 2.93 1.85 53 66.00 2.00 1496 4/11 34.91 -0.68 2299.6 2163.7 8.039 1.71 1.09 53 66.00 2.00 1185 4/11 34.91 -0.55 2300.3 2166.1 8.045 1.82 1.16 53 66.00 2.00 986 4/11 34.91 -0.38 2299.3 2188.3 7.985 1.67 1.06 53 66.00 2.00 791 4/11 34.91 -0.11 2301.2 2181.2 8.015 1.85 1.17 53 66.00 2.00 495 4/11 34.96 2.46 2301.6 2168.7 8.02 2.16 1.37 53 66.00 2.00 394 4/11 35.08 5.96 2314.9 2156.1 8.032 2.58 1.64 53 66.00 2.00 296 4/11 35.13 6.63 2314.5 2152.2 8.033 2.69 1.71 53 66.00 2.00 197 4/11 35.13 7.02 2313.9 2149.8 8.035 2.77 1.76 53 66.00 2.00 102 4/11 35.14 7.18 2322.8 2155.6 8.043 2.88 1.83 53 66.00 2.00 50 4/11 35.14 7.18 2315.7 2149.1 8.044 2.90 1.84 53 66.00 2.00 31 4/11 35.14 7.18 2315.5 2147.6 8.048 2.93 1.85 613 65.875 2.102 1960 6/24 34.91 -0.79 2304.5 2167.2 8.025 1.54 0.99 613 65.875 2.102 1479 6/24 34.91 -0.66 2302.6 2166.0 8.041 1.72 1.10 613 65.875 2.102 986 6/24 34.91 -0.38 2302.5 2170.3 8.045 1.89 1.20 613 65.875 2.102 493 6/24 34.98 3.39 2306.2 2169.1 8.015 2.22 1.41 613 65.875 2.102 294 6/24 35.10 6.82 2313.4 2150.9 8.03 2.69 1.71 613 65.875 2.102 194 6/24 35.12 7.38 2313.1 2149.7 8.028 2.76 1.76 613 65.875 2.102 95 6/24 35.15 7.75 2315.9 2148.8 8.034 2.88 1.83 613 65.875 2.102 47 6/24 35.19 8.20 2318.0 2147.3 8.036 2.96 1.88 613 65.875 2.102 29 6/24 35.19 8.48 2317.6 2147.4 8.031 2.97 1.88 613 65.875 2.102 8 6/24 34.98 10.42 2318.7 2074.9 8.161 4.08 2.60 613 65.875 2.102 5 6/24 34.98 10.69 2317.8 2075.9 8.154 4.06 2.58 347 66.000 2.000 1478 8/15 34.91 -0.69 2301.2 2166.0 8.038 1.71 1.09 347 66.000 2.000 1183 8/15 34.91 -0.51 2300.3 2169.8 8.034 1.79 1.14 347 66.000 2.000 987 8/15 34.91 -0.30 2299.8 2172.7 8.03 1.84 1.17 347 66.000 2.000 790 8/15 34.91 0.15 2298.8 2176.9 8.016 1.87 1.19 347 66.000 2.000 494 8/15 35.00 4.51 2307.2 2159.4 8.025 2.37 1.50 347 66.000 2.000 395 8/15 35.10 6.24 2316.3 2154.8 8.034 2.62 1.66 347 66.000 2.000 294 8/15 35.11 6.71 2320.7 2154.4 8.041 2.75 1.74 347 66.000 2.000 197 8/15 35.11 7.01 2310.1 2153.5 8.018 2.67 1.69 347 66.000 2.000 97 8/15 35.13 7.57 2311.8 2155.9 8.01 2.72 1.73 347 66.000 2.000 48 8/15 35.15 7.95 2315.1 2153.4 8.02 2.84 1.80 347 66.000 2.000 27 8/15 35.14 8.51 2317.5 2149.8 8.026 2.94 1.87 347 66.000 2.000 8 8/15 35.01 11.94 2310.9 2071.9 8.131 4.03 2.57

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629 65.838 2.191 1947 11/20 34.91 -0.78 2309.0 2158.6 8.059 1.66 1.07 629 65.838 2.191 1480 11/20 34.91 -0.69 2305.0 2167.4 8.044 1.73 1.11 629 65.838 2.191 988 11/20 34.91 -0.40 2303.0 2163.4 8.065 1.97 1.25 629 65.838 2.191 497 11/20 34.94 2.02 2303.6 2172.1 8.023 2.14 1.36 629 65.838 2.191 297 11/20 35.12 7.37 2316.5 629 65.838 2.191 198 11/20 35.14 8.26 2318.2 2155.0 8.013 2.77 1.76 629 65.838 2.191 100 11/20 35.20 9.22 2319.4 2144.3 8.029 3.00 1.91 629 65.838 2.191 50 11/20 35.04 9.01 2315.9 2130.6 8.06 3.18 2.02 629 65.838 2.191 30 11/20 35.04 9.00 2316.2 2139.8 8.041 3.07 1.95 629 65.838 2.191 20 11/20 35.04 9.00 2313.2 2128.4 8.061 3.19 2.03 629 65.838 2.191 11 11/20 35.04 9.00 2312.5 2127.8 8.061 3.20 2.03 629 65.838 2.191 6 11/20 35.04 9.00 2315.4 2126.5 8.07 3.26 2.07

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Table 7. Gimsøy-NW, April and June 2017.

Stn Date Lat Lon Depth T S AT CT pHT Ca Ar N E (m) (C°) (µmol kg-1) (µmol kg-1) 41 8.4. 68,567 13,583 129 7,28 34,96 2314 2145 8,048 2,89 1,83 41 8.4. 68,567 13,583 99 6,43 34,56 2302 2134 8,065 2,88 1,82 41 8.4. 68,567 13,583 75 6,18 34,45 2304 2131 8,087 2,99 1,89 41 8.4. 68,567 13,583 49 6,00 34,33 2298 2128 8,082 2,94 1,86 41 8.4. 68,567 13,583 28 5,80 34,14 2296 2129 8,084 2,93 1,85 41 8.4. 68,567 13,583 20 5,49 33,95 2274 2106 8,097 2,94 1,85 41 8.4. 68,567 13,583 11 5,35 33,91 2278 2100 8,123 3,09 1,95 41 8.4. 68,567 13,583 6 5,30 33,90 2283 2116 8,096 2,93 1,85 43 8.4. 68,733 13,167 108 7,30 35,03 2332 2160 8,053 2,95 1,87 43 8.4. 68,733 13,167 100 7,30 35,03 2318 2150 8,045 2,89 1,83 43 8.4. 68,733 13,167 73 7,33 35,03 2319 2148 8,051 2,94 1,86 43 8.4. 68,733 13,167 51 7,35 34,99 2324 2151 8,056 2,99 1,89 43 8.4. 68,733 13,167 30 6,92 34,81 2318 2145 8,069 3,01 1,91 43 8.4. 68,733 13,167 19 6,87 34,75 2297 2142 8,029 2,75 1,74 43 8.4. 68,733 13,167 8 6,36 34,59 2307 2137 8,074 2,97 1,88 45 8.4. 68,850 12,800 673 4,60 35,09 2340 2182 8,037 2,41 1,54 45 8.4. 68,850 12,800 602 5,24 35,13 2348 2162 8,097 2,82 1,80 45 8.4. 68,850 12,800 501 5,72 35,15 2325 2164 8,034 2,54 1,62 45 8.4. 68,850 12,800 401 5,89 35,15 2320 2157 8,040 2,62 1,67 45 8.4. 68,850 12,800 299 6,08 35,14 2325 2160 8,047 2,72 1,73 45 8.4. 68,850 12,800 200 6,19 35,14 2324 2157 8,053 2,80 1,78 45 8.4. 68,850 12,800 150 6,37 35,15 2323 2158 8,048 2,81 1,78 45 8.4. 68,850 12,800 99 6,45 35,14 2330 2144 8,096 3,13 1,98 45 8.4. 68,850 12,800 75 6,48 35,14 2323 2153 8,062 2,93 1,85 45 8.4. 68,850 12,800 50 6,49 35,14 2321 2153 8,060 2,92 1,85 45 8.4. 68,850 12,800 29 6,49 35,14 2321 2149 8,069 2,98 1,89 45 8.4. 68,850 12,800 12 6,56 35,14 2326 2142 8,096 3,18 2,01 47 9.4. 69,033 12,283 1487 -0,59 34,92 2330 2169 8,101 1,98 1,27 47 9.4. 69,033 12,283 1199 -0,41 34,91 2333 2198 8,041 1,84 1,18 47 9.4. 69,033 12,283 999 -0,19 34,91 2321 2179 8,066 2,00 1,27 47 9.4. 69,033 12,283 800 0,87 34,93 2309 2181 8,020 1,95 1,24 47 9.4. 69,033 12,283 501 5,48 35,14 2323 2164 8,036 2,53 1,61 47 9.4. 69,033 12,283 399 6,01 35,15 2328 2161 8,049 2,69 1,71 47 9.4. 69,033 12,283 298 6,21 35,15 2336 2151 8,091 3,00 1,90 47 9.4. 69,033 12,283 200 6,47 35,14 2345 2173 8,060 2,90 1,84 47 9.4. 69,033 12,283 100 6,57 35,14 2340 2158 8,084 3,08 1,95 47 9.4. 69,033 12,283 50 6,61 35,11 2321 2151 8,063 2,95 1,87 47 9.4. 69,033 12,283 31 6,64 35,11 2334 2156 8,078 3,07 1,94 47 9.4. 69,033 12,283 12 6,63 35,12 2328 2151 8,078 3,07 1,94 50 9.4. 69,483 10,950 1520 -0,54 34,92 2318 2137 8,149 2,16 1,38 50 9.4. 69,483 10,950 1199 -0,24 34,92 2315 2177 8,049 1,87 1,19 50 9.4. 69,483 10,950 1000 0,20 34,92 2313 2178 8,042 1,93 1,23 50 9.4. 69,483 10,950 800 2,40 34,97 2319 2173 8,042 2,18 1,38 50 9.4. 69,483 10,950 498 5,69 35,14 2327 2161 8,048 2,62 1,67 50 9.4. 69,483 10,950 400 6,09 35,15 2339 2174 8,041 2,67 1,70 50 9.4. 69,483 10,950 298 6,28 35,13 2331 2157 8,067 2,86 1,81

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50 9.4. 69,483 10,950 199 6,44 35,14 2330 2159 8,060 2,87 1,82 50 9.4. 69,483 10,950 100 6,69 35,12 2327 2156 8,060 2,93 1,86 50 9.4. 69,483 10,950 50 6,75 35,13 2327 2151 8,071 3,02 1,91 50 9.4. 69,483 10,950 31 6,76 35,13 2333 2157 8,074 3,06 1,94 50 9.4. 69,483 10,950 9 6,71 35,10 2330 2144 8,098 3,21 2,03 52 9.4. 69,950 9,583 1496 -0,60 34,92 2324 2184 8,046 1,76 1,13 52 9.4. 69,950 9,583 1200 -0,45 34,92 2306 2169 8,051 1,86 1,18 52 9.4. 69,950 9,583 998 -0,22 34,92 2320 2188 8,042 1,91 1,21 52 9.4. 69,950 9,583 800 0,24 34,92 2332 2192 8,061 2,09 1,33 52 9.4. 69,950 9,583 500 4,45 35,08 2329 2141 8,120 2,89 1,83 52 9.4. 69,950 9,583 401 5,37 35,14 2325 2158 8,060 2,68 1,70 52 9.4. 69,950 9,583 299 5,64 35,12 2330 2141 8,109 3,03 1,92 52 9.4. 69,950 9,583 201 6,15 35,15 2327 2150 8,077 2,94 1,86 52 9.4. 69,950 9,583 102 6,60 35,15 2342 2160 8,083 3,08 1,95 52 9.4. 69,950 9,583 51 6,62 35,15 2339 2150 8,100 3,21 2,03 52 9.4. 69,950 9,583 31 6,71 35,14 2335 2147 8,098 3,21 2,03 52 9.4. 69,950 9,583 11 6,71 35,15 2323 2148 8,073 3,05 1,93 193 6.6. 69,031 12,186 2009 -0,76 34,91 2313 2168 8,042 1,60 1,03 193 6.6. 69,031 12,186 1500 -0,67 34,91 2310 2167 8,057 1,78 1,14 193 6.6. 69,031 12,186 1000 -0,30 34,91 2332 2184 8,083 2,07 1,32 193 6.6. 69,031 12,186 800 0,17 34,91 2330 2192 8,057 2,06 1,31 193 6.6. 69,031 12,186 499 4,94 35,13 2328 2154 8,080 2,71 1,72 193 6.6. 69,031 12,186 400 5,32 35,13 2316 2158 8,039 2,55 1,62 193 6.6. 69,031 12,186 199 6,81 35,11 2325 2153 8,056 2,88 1,83 193 6.6. 69,031 12,186 99 7,47 35,14 2331 2157 8,054 2,98 1,89 193 6.6. 69,031 12,186 50 7,55 35,06 2323 2148 8,059 3,03 1,92 193 6.6. 69,031 12,186 31 7,36 34,90 2333 2153 8,075 3,12 1,98 193 6.6. 69,031 12,186 12 7,45 34,08 2303 2125 8,083 3,11 1,97 190 6.6. 69,480 10,950 1968 -0,68 34,91 2324 2178 8,047 1,64 1,06 190 6.6. 69,480 10,950 1500 -0,44 34,91 2309 2169 8,046 1,76 1,13 190 6.6. 69,480 10,950 1000 1,26 34,93 2328 2185 8,045 2,04 1,30 190 6.6. 69,480 10,950 798 4,89 35,11 2334 2168 8,049 2,45 1,56 190 6.6. 69,480 10,950 499 6,15 35,14 2336 2169 8,042 2,64 1,68 190 6.6. 69,480 10,950 400 6,35 35,13 2336 2162 8,059 2,79 1,77 190 6.6. 69,480 10,950 200 6,77 35,12 2325 2152 8,060 2,90 1,84 190 6.6. 69,480 10,950 100 6,92 35,12 2342 2151 8,099 3,21 2,04 190 6.6. 69,480 10,950 49 6,93 35,13 2335 2149 8,093 3,19 2,02 190 6.6. 69,480 10,950 30 6,93 35,13 2338 2141 8,115 3,35 2,12 190 6.6. 69,480 10,950 11 6,93 35,12 2337 2144 8,109 3,31 2,10 188 5.6. 69,950 9,588 2009 -0,74 34,91 2326 2155 8,108 1,84 1,19 188 5.6. 69,950 9,588 1499 -0,58 34,91 2313 2169 8,058 1,80 1,15 188 5.6. 69,950 9,588 999 -0,05 34,91 2332 2190 8,062 2,01 1,28 188 5.6. 69,950 9,588 800 1,03 34,92 2326 2166 8,101 2,33 1,48 188 5.6. 69,950 9,588 497 4,93 35,12 2338 2159 8,090 2,78 1,77 188 5.6. 69,950 9,588 399 5,16 35,13 2328 2160 8,064 2,69 1,71 188 5.6. 69,950 9,588 199 5,89 35,11 2337 2157 8,087 2,98 1,89 188 5.6. 69,950 9,588 99 6,45 35,12 2326 2149 8,078 3,01 1,91 188 5.6. 69,950 9,588 49 6,97 35,11 2331 2131 8,124 3,39 2,15 188 5.6. 69,950 9,588 30 7,52 35,07 2338 2149 8,090 3,25 2,06

93 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

188 5.6. 69,950 9,588 10 7,74 35,08 2341 2124 8,146 3,66 2,32

Table 8. Skrova coastal station, January-December 2017.

Date Lat Lon Depth T S AT CT pHT Ca Ar NO3 PO4 SiOH4 N E (m) (C°) (µmol kg-1) (µmol kg-1) (µmol/kg) (µmol/kg) (µmol/kg) 24.1. 68,117 14,532 300 7,53 34,98 2320 2151 8,035 1,77 2,79 12,1 0,83 5,9 24.1. 68,117 14,532 250 7,50 34,79 2336 2157 8,062 1,89 2,97 11,7 0,79 5,6 24.1. 68,117 14,532 200 7,57 34,59 2326 2191 7,959 1,54 2,42 11,2 0,79 5,3 24.1. 68,117 14,532 150 8,10 34,00 2329 2169 8,023 1,78 2,80 9,3 0,65 4,0 24.1. 68,117 14,532 100 6,66 32,75 2276 2109 8,085 1,84 2,92 6,4 0,46 2,6 24.1. 68,117 14,532 75 6,01 32,50 2235 2079 8,078 1,74 2,76 6,1 0,47 2,8 24.1. 68,117 14,532 50 5,91 32,48 2216 2063 8,074 1,71 2,71 5,0 0,37 2,5 24.1. 68,117 14,532 30 5,92 32,46 2225 2062 8,100 1,81 2,88 3,9 0,28 1,8 24.1. 68,117 14,532 20 5,76 32,42 2219 2064 8,085 1,74 2,77 3,9 0,28 1,8 24.1. 68,117 14,532 10 5,64 32,38 2210 2063 8,069 1,68 2,66 3,9 0,29 1,8 24.1. 68,117 14,532 5 5,63 32,39 2220 2071 8,071 1,69 2,69 3,9 0,28 1,8 24.1. 68,117 14,532 1 5,62 32,33 2217 2066 8,078 1,71 2,73 3,9 0,28 1,8 21.2. 68,117 14,532 300 7,54 34,99 2335 2163 8,040 1,80 2,84 12,1 0,83 5,9 21.2. 68,117 14,532 250 7,65 34,86 2327 2194 7,946 1,50 2,36 11,7 0,79 5,6 21.2. 68,117 14,532 200 7,90 34,70 2342 2182 8,015 1,75 2,76 11,2 0,79 5,3 21.2. 68,117 14,532 150 7,40 34,29 2341 2178 8,036 1,80 2,84 9,3 0,65 4,0 21.2. 68,117 14,532 100 6,80 33,86 2302 2141 8,052 1,78 2,82 6,4 0,46 2,6 21.2. 68,117 14,532 75 6,09 33,47 2249 2102 8,040 1,65 2,62 6,1 0,47 2,8 21.2. 68,117 14,532 50 5,75 32,95 2223 2081 8,041 1,61 2,55 5,0 0,37 2,5 21.2. 68,117 14,532 30 4,50 32,48 2231 2081 8,089 1,69 2,70 4,5 0,33 2,1 21.2. 68,117 14,532 20 4,07 32,37 2211 2062 8,096 1,67 2,66 4,3 0,31 2,1 21.2. 68,117 14,532 10 3,95 32,32 2192 2056 8,065 1,55 2,48 4,4 0,32 3,3 21.2. 68,117 14,532 5 3,94 32,29 2206 2057 8,103 1,69 2,69 4,4 0,35 2,2 21.2. 68,117 14,532 1 3,93 32,28 2199 2059 8,078 1,60 2,55 4,4 0,33 2,2 31.3. 68,117 14,532 300 7,65 35,02 2331 2170 8,013 1,72 2,70 12,2 0,82 6,0 31.3. 68,117 14,532 200 7,82 34,73 2336 2179 8,007 1,72 2,71 11,4 0,77 5,1 31.3. 68,117 14,532 150 7,86 34,57 2282 2127 8,013 1,71 2,69 10,5 0,71 4,6 31.3. 68,117 14,532 100 7,69 34,36 2312 2173 7,976 1,60 2,52 7,2 0,48 2,9 31.3. 68,117 14,532 75 6,96 33,95 2297 2146 8,027 1,71 2,70 7,3 0,50 3,0 31.3. 68,117 14,532 50 3,79 32,85 2278 2131 8,082 1,67 2,66 4,7 0,35 2,2 31.3. 68,117 14,532 30 3,40 32,80 2232 2097 8,064 1,56 2,48 3,2 0,27 1,4 31.3. 68,117 14,532 20 3,36 32,78 2206 2085 8,028 1,43 2,28 2,4 0,23 1,1 31.3. 68,117 14,532 10 3,34 32,77 2206 2064 8,085 1,61 2,56 2,2 0,22 1,1 31.3. 68,117 14,532 5 3,34 32,77 2195 2067 8,048 1,48 2,36 2,3 0,24 1,1 31.3. 68,117 14,532 1 3,34 32,74 2200 2057 8,090 1,62 2,58 2,1 0,22 1,0 25.4. 68,117 14,532 300 7,67 34,87 2319 2176 7,971 1,56 2,46 12,6 0,82 6,2 25.4. 68,117 14,532 200 7,77 34,73 2314 2160 8,003 1,69 2,65 12,1 0,79 5,9 25.4. 68,117 14,532 150 7,82 34,64 2308 2158 7,997 1,67 2,64 11,3 0,75 5,1 25.4. 68,117 14,532 100 7,77 34,46 2276 2113 8,035 1,78 2,81 9,2 0,61 3,8 25.4. 68,117 14,532 75 6,95 34,07 2275 2120 8,037 1,73 2,74 8,3 0,58 3,1 25.4. 68,117 14,532 50 4,88 33,30 2225 2078 8,066 1,65 2,62 0,9 0,14 1,0 25.4. 68,117 14,532 30 3,95 32,66 2216 2062 8,109 1,72 2,74 0,6 0,12 0,9 25.4. 68,117 14,532 20 3,77 32,55 2221 2061 8,129 1,78 2,84 0,0 0,09 0,7

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25.4. 68,117 14,532 10 3,77 32,53 2220 2058 8,131 1,79 2,86 0,0 0,08 0,7 25.4. 68,117 14,532 5 3,77 32,53 2218 2062 8,116 1,74 2,77 0,0 0,12 0,7 25.4. 68,117 14,532 1 3,78 32,51 2214 2056 8,122 1,76 2,80 0,1 0,08 0,7 21.5. 68,117 14,532 300 7,62 35,00 2324 2167 8,004 1,68 2,64 12,5 0,78 6,6 21.5. 68,117 14,532 200 7,70 34,86 2329 2174 8,003 1,70 2,67 11,8 0,74 5,5 21.5. 68,117 14,532 150 7,73 34,82 2311 2152 8,016 1,74 2,74 11,8 0,71 5,4 21.5. 68,117 14,532 100 7,75 34,70 2313 2137 8,062 1,92 3,03 11,0 0,70 4,9 21.5. 68,117 14,532 75 7,59 34,57 2316 2158 8,023 1,77 2,79 10,4 0,65 4,4 21.5. 68,117 14,532 50 6,74 34,08 2262 2099 8,061 1,80 2,85 5,9 0,44 2,8 21.5. 68,117 14,532 30 5,06 33,27 2260 2088 8,122 1,89 3,01 1,0 0,20 1,0 21.5. 68,117 14,532 20 5,42 32,78 2236 2069 8,115 1,86 2,95 0,1 0,08 0,8 21.5. 68,117 14,532 10 5,71 32,80 2228 2047 8,144 1,98 3,15 0,1 0,10 0,7 21.5. 68,117 14,532 5 6,21 32,69 2226 2058 8,107 1,87 2,97 0,1 0,08 0,7 21.5. 68,117 14,532 1 7,23 32,47 2216 2038 8,119 1,97 3,12 0,1 0,08 0,7 22.6. 68,117 14,532 300 7,63 35,02 2318 2180 7,956 1,52 2,39 12,5 0,82 6,3 22.6. 68,117 14,532 200 7,67 34,97 2321 2166 8,003 1,69 2,67 11,8 0,74 5,2 22.6. 68,117 14,532 150 7,68 34,91 2318 2168 7,995 1,67 2,64 12,1 0,75 5,4 22.6. 68,117 14,532 125 7,70 34,82 2331 2175 8,011 1,74 2,74 11,8 0,74 5,2 22.6. 68,117 14,532 100 7,69 34,76 2308 2166 7,978 1,62 2,55 11,6 0,75 5,1 22.6. 68,117 14,532 75 7,69 34,66 2305 2159 7,991 1,66 2,62 10,9 0,70 4,6 22.6. 68,117 14,532 50 7,20 34,39 2292 2148 8,001 1,65 2,61 10,2 0,64 3,8 22.6. 68,117 14,532 30 6,46 33,52 2297 2118 8,108 1,98 3,13 4,5 0,38 2,2 22.6. 68,117 14,532 20 8,18 32,84 2266 2091 8,084 1,95 3,09 2,1 0,28 1,9 22.6. 68,117 14,532 10 10,73 32,83 2231 2078 7,997 1,77 2,78 0,1 0,17 1,3 22.6. 68,117 14,532 5 10,87 32,77 2214 2020 8,096 2,14 3,37 0,1 0,11 1,1 22.6. 68,117 14,532 1 11,00 32,68 2220 2071 7,987 1,73 2,73 0,1 0,09 1,1 26.7. 68,117 14,532 300 7,60 35,03 2312 2152 8,011 1,69 2,66 11,9 0,79 5,8 26.7. 68,117 14,532 200 7,63 34,95 2310 2151 8,014 1,72 2,71 11,7 0,73 5,1 26.7. 68,117 14,532 150 7,64 34,81 2322 2161 8,024 1,77 2,79 11,6 0,73 5,0 26.7. 68,117 14,532 125 7,61 34,74 2337 2167 8,045 1,86 2,93 11,4 0,74 4,9 26.7. 68,117 14,532 100 7,42 34,58 2313 2159 8,015 1,72 2,72 10,3 0,67 4,2 26.7. 68,117 14,532 75 7,15 34,34 2288 2146 7,994 1,61 2,55 9,2 0,62 3,4 26.7. 68,117 14,532 50 7,19 34,06 2283 2124 8,043 1,78 2,81 6,5 0,49 2,6 26.7. 68,117 14,532 30 9,82 33,36 2234 2026 8,133 2,25 3,55 0,1 0,09 0,7 26.7. 68,117 14,532 20 12,03 32,77 2199 2018 8,051 2,02 3,18 0,1 0,05 0,6 26.7. 68,117 14,532 10 12,86 32,25 2168 2023 7,959 1,70 2,67 0,1 0,06 0,5 26.7. 68,117 14,532 5 13,56 31,74 2147 1984 8,006 1,88 2,95 0,1 0,05 0,5 26.7. 68,117 14,532 1 14,25 31,09 2122 1925 8,085 2,19 3,45 0,0 0,05 0,6 23.8. 68,117 14,532 300 7,59 35,03 2323 2172 7,991 1,63 2,57 12,2 0,79 6,0 23.8. 68,117 14,532 200 7,62 34,88 2305 2148 8,013 1,71 2,69 11,7 0,74 5,0 23.8. 68,117 14,532 150 7,49 34,78 2314 2164 7,998 1,67 2,63 11,1 0,68 4,6 23.8. 68,117 14,532 125 7,39 34,56 2316 2160 8,019 1,73 2,73 9,2 0,61 3,5 23.8. 68,117 14,532 100 7,65 34,31 2295 2119 8,069 1,91 3,01 7,8 0,55 2,8 23.8. 68,117 14,532 75 8,60 34,04 2278 2113 8,038 1,84 2,90 5,2 0,42 1,8 23.8. 68,117 14,532 50 11,32 33,69 2276 2070 8,094 2,25 3,53 0,3 0,14 0,3 23.8. 68,117 14,532 30 13,18 33,06 2259 2045 8,096 2,36 3,71 0,1 0,07 0,2 23.8. 68,117 14,532 20 13,41 32,91 2239 2043 8,058 2,19 3,44 0,1 0,05 0,2 23.8. 68,117 14,532 10 13,21 32,54 2206 2005 8,082 2,24 3,51 0,1 0,06 0,3 23.8. 68,117 14,532 5 13,18 32,29 2196 2008 8,057 2,11 3,32 0,1 0,05 0,3

95 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

23.8. 68,117 14,532 1 13,38 32,14 2179 2002 8,031 2,00 3,14 0,1 0,04 0,3 13.9. 68,117 14,532 300 7,58 35,03 2309 2180 7,936 1,45 2,28 12,4 0,80 5,9 13.9. 68,117 14,532 200 7,56 34,80 2313 2144 8,042 1,81 2,85 12,1 0,77 5,1 13.9. 68,117 14,532 150 7,32 34,47 2313 2169 7,990 1,62 2,55 9,6 0,63 3,6 13.9. 68,117 14,532 125 7,62 34,23 2318 2159 8,028 1,77 2,79 7,8 0,52 2,7 13.9. 68,117 14,532 100 8,71 34,11 2291 2120 8,045 1,88 2,96 5,7 0,46 1,9 13.9. 68,117 14,532 75 10,72 33,72 2267 2088 8,043 1,98 3,11 2,4 0,26 0,8 13.9. 68,117 14,532 50 12,65 33,07 2249 2044 8,084 2,25 3,53 0,3 0,10 0,5 13.9. 68,117 14,532 30 12,55 32,49 2205 2003 8,092 2,22 3,49 0,2 0,07 0,5 13.9. 68,117 14,532 20 12,52 32,40 2197 2012 8,059 2,08 3,26 0,2 0,08 0,5 13.9. 68,117 14,532 10 12,39 31,74 2144 1963 8,066 2,02 3,18 0,2 0,07 0,8 13.9. 68,117 14,532 5 12,37 31,49 2145 1953 8,096 2,14 3,37 0,2 0,05 0,8 13.9. 68,117 14,532 1 12,37 31,49 2140 1974 8,033 1,88 2,97 0,2 0,06 0,8 19.10. 68,117 14,532 300 7,66 34,97 2318 2168 7,988 1,62 2,54 12,4 0,82 6,0 19.10. 68,117 14,532 200 7,49 34,67 2315 2169 7,988 1,62 2,55 11,7 0,76 4,9 19.10. 68,117 14,532 150 7,76 34,29 2318 2152 8,041 1,82 2,87 9,3 0,62 3,5 19.10. 68,117 14,532 125 8,26 34,12 2325 2136 8,090 2,05 3,23 7,5 0,51 2,6 19.10. 68,117 14,532 100 10,10 33,81 2274 2100 8,037 1,92 3,02 5,9 0,43 1,8 19.10. 68,117 14,532 75 11,66 33,47 2257 2059 8,075 2,16 3,39 3,7 0,32 1,1 19.10. 68,117 14,532 50 11,17 32,69 2228 2032 8,095 2,16 3,40 1,3 0,14 0,7 19.10. 68,117 14,532 30 10,94 32,55 2213 2025 8,082 2,07 3,27 0,8 0,10 0,7 19.10. 68,117 14,532 20 10,94 32,49 2222 2027 8,098 2,15 3,39 0,9 0,12 0,7 19.10. 68,117 14,532 10 10,94 32,46 2229 2040 8,086 2,11 3,32 0,9 0,12 0,8 19.10. 68,117 14,532 5 10,81 32,40 2225 2023 8,119 2,23 3,52 0,8 0,10 0,8 19.10. 68,117 14,532 1 10,61 32,32 2218 2045 8,055 1,95 3,07 0,8 0,11 0,9 12.11. 68,117 14,532 300 7,61 34,99 2317 2171 7,979 1,59 2,50 12,7 0,85 6,1 12.11. 68,117 14,532 200 7,56 34,76 2320 2157 8,026 1,76 2,77 11,7 0,79 5,2 12.11. 68,117 14,532 150 7,69 34,37 2307 2148 8,025 1,75 2,76 9,8 0,68 4,0 12.11. 68,117 14,532 125 9,13 34,00 2276 2113 8,021 1,80 2,83 5,2 0,44 1,8 12.11. 68,117 14,532 100 9,70 32,85 2241 2065 8,064 1,94 3,05 2,2 0,20 1,0 12.11. 68,117 14,532 75 9,63 32,82 2233 2056 8,070 1,95 3,08 2,0 0,17 1,0 12.11. 68,117 14,532 50 9,57 32,79 2227 2046 8,083 2,00 3,15 2,0 0,17 1,0 12.11. 68,117 14,532 30 9,57 32,75 2270 2059 8,146 2,31 3,64 2,0 0,18 1,0 12.11. 68,117 14,532 20 9,57 32,74 2230 2049 8,084 2,01 3,17 1,9 0,19 1,0 12.11. 68,117 14,532 10 9,57 32,67 2231 2046 8,094 2,05 3,24 2,0 0,19 1,0 12.11. 68,117 14,532 5 9,57 32,64 2236 2051 8,094 2,06 3,25 2,0 0,19 1,0 12.11. 68,117 14,532 1 9,57 32,65 2243 2057 8,096 2,07 3,27 2,0 0,18 1,0 11.12. 68,117 14,532 200 7,59 34,82 2349 2190 8,014 1,74 2,74 12,2 0,83 5,9 11.12. 68,117 14,532 150 7,53 34,54 2322 2172 8,001 1,68 2,64 10,5 0,72 4,6 11.12. 68,117 14,532 125 7,86 34,23 2305 2151 8,011 1,72 2,71 8,6 0,57 3,4 11.12. 68,117 14,532 100 9,64 33,69 2267 2096 8,040 1,89 2,97 4,2 0,34 1,5 11.12. 68,117 14,532 75 8,08 32,91 2240 2067 8,084 1,91 3,02 2,9 0,25 1,3 11.12. 68,117 14,532 50 7,75 32,79 2250 2090 8,056 1,79 2,84 2,9 0,24 1,3 11.12. 68,117 14,532 30 7,70 32,74 2247 2069 8,104 1,97 3,13 2,9 0,25 1,3 11.12. 68,117 14,532 20 7,67 32,72 2246 2076 8,085 1,90 3,01 2,8 0,24 1,3 11.12. 68,117 14,532 10 7,65 32,65 2286 2107 8,103 2,00 3,17 2,8 0,27 1,2 11.12. 68,117 14,532 5 7,61 32,62 2246 2084 8,069 1,84 2,91 2,9 0,25 1,3 11.12. 68,117 14,532 1 7,60 32,63 2236 2064 8,094 1,92 3,05 2,9 0,18 1,3

96 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Table 9. Fugløya-Bjørnøya, February and April 2017.

Stn Date Lat Lon Depth T S AT CT pHT Ca Ar N E (m) (C°) (µmol kg-1) (µmol kg-1) 85 21.2. 71,748 19,723 298 6,17 35,08 2321 2153 8,054 2,76 1,75 85 21.2. 71,748 19,723 199 6,34 35,04 2328 2153 8,071 2,92 1,85 85 21.2. 71,748 19,723 150 6,36 35,05 2336 2161 8,072 2,96 1,87 85 21.2. 71,748 19,723 74 6,35 35,05 2320 2150 8,065 2,93 1,85 85 21.2. 71,748 19,723 29 6,34 35,05 2331 2152 8,086 3,08 1,95 85 21.2. 71,748 19,723 9 6,34 35,05 2321 2149 8,073 3,00 1,90 8 1.4. 71,750 19,733 254 5,87 35,09 2344 2172 8,069 2,86 1,81 8 1.4. 71,750 19,733 199 5,90 35,09 2326 2156 8,067 2,85 1,80 8 1.4. 71,750 19,733 148 5,97 35,08 2341 2163 8,086 3,01 1,90 8 1.4. 71,750 19,733 123 5,98 35,08 2326 2152 8,077 2,95 1,87 8 1.4. 71,750 19,733 98 6,04 35,07 2322 2151 8,070 2,91 1,85 8 1.4. 71,750 19,733 74 6,01 35,06 2346 2170 8,083 3,03 1,92 8 1.4. 71,750 19,733 50 6,00 35,05 2340 2164 8,082 3,02 1,91 8 1.4. 71,750 19,733 30 5,99 35,05 2333 2156 8,087 3,05 1,93 8 1.4. 71,750 19,733 21 5,98 35,05 2338 2160 8,089 3,08 1,95 8 1.4. 71,750 19,733 10 5,96 35,04 2316 2156 8,050 2,82 1,78 8 1.4. 71,750 19,733 7 5,95 35,04 2317 2149 8,068 2,92 1,85 12 2.4. 72,750 19,517 386 4,58 35,08 2320 2161 8,056 2,58 1,64 12 2.4. 72,750 19,517 302 5,59 35,12 2342 2168 8,075 2,84 1,80 12 2.4. 72,750 19,517 251 5,63 35,13 2336 2164 8,070 2,83 1,80 12 2.4. 72,750 19,517 200 5,69 35,13 2322 2158 8,057 2,77 1,76 12 2.4. 72,750 19,517 150 5,69 35,13 2338 2167 8,073 2,90 1,84 12 2.4. 72,750 19,517 100 5,69 35,12 2323 2155 8,069 2,88 1,82 12 2.4. 72,750 19,517 75 5,70 35,12 2328 2154 8,084 2,98 1,89 12 2.4. 72,750 19,517 50 5,69 35,12 2324 2147 8,092 3,04 1,92 12 2.4. 72,750 19,517 30 5,69 35,12 2332 2162 8,074 2,94 1,86 12 2.4. 72,750 19,517 21 5,68 35,12 2327 2157 8,077 2,96 1,87 12 2.4. 72,750 19,517 11 5,69 35,45 2320 2157 8,056 2,84 1,80 12 2.4. 72,750 19,517 6 5,69 35,12 2321 2158 8,060 2,86 1,81 82 21.2. 72,503 19,558 381 4,72 35,03 2325 2163 8,060 2,62 1,66 82 21.2. 72,503 19,558 301 6,12 35,05 2323 2154 8,057 2,77 1,76 82 21.2. 72,503 19,558 249 6,12 35,05 2327 2152 8,074 2,89 1,83 82 21.2. 72,503 19,558 201 6,12 35,05 2323 2152 8,065 2,86 1,81 82 21.2. 72,503 19,558 150 6,11 35,05 2333 2160 8,073 2,93 1,86 82 21.2. 72,503 19,558 98 6,11 35,05 2322 2153 8,065 2,89 1,83 82 21.2. 72,503 19,558 73 6,11 35,05 2322 2155 8,061 2,88 1,82 82 21.2. 72,503 19,558 49 6,10 35,05 2328 2167 8,047 2,81 1,78 82 21.2. 72,503 19,558 29 6,10 35,05 2333 2150 8,099 3,14 1,99 82 21.2. 72,503 19,558 18 6,10 35,05 2335 2147 8,111 3,22 2,04 82 21.2. 72,503 19,558 10 6,09 35,05 2331 2139 8,121 3,29 2,08 77 21.2. 73,668 19,303 341 3,83 34,98 2323 2171 8,053 2,51 1,59 77 21.2. 73,668 19,303 100 5,32 35,04 2329 2145 8,111 3,09 1,95 77 21.2. 73,668 19,303 75 5,32 35,05 2330 2153 8,097 3,02 1,91 77 21.2. 73,668 19,303 49 5,33 35,05 2321 2153 8,079 2,91 1,84 77 21.2. 73,668 19,303 29 5,34 35,05 2322 2159 8,066 2,85 1,80 77 21.2. 73,668 19,303 18 5,33 35,05 2325 2159 8,075 2,91 1,84

97 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

77 21.2. 73,668 19,303 10 5,32 35,05 2323 2160 8,067 2,86 1,81 74 20.2. 74,251 19,166 51 0,98 34,67 2306 2138 8,157 2,88 1,81 74 20.2. 74,251 19,166 31 1,00 34,68 2304 2137 8,154 2,87 1,80 74 20.2. 74,251 19,166 21 1,00 34,68 2311 2129 8,191 3,10 1,95 74 20.2. 74,251 19,166 10 0,99 34,68 2307 2122 8,197 3,14 1,97 74 20.2. 74,251 19,166 6 0,99 34,68 2306 2129 8,181 3,04 1,91

98 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

Table 10. Barents Sea, September 2017.

Stn Date Lat Lon Depth T S AT CT pHT Ca Ar N E (m) (C°) (µmol kg-1) (µmol kg-1) 523 30.9. 77,004 34,001 149 1,13 34,88 2304 2196 7,985 2,01 1,27 523 30.9. 77,004 34,001 125 1,17 34,89 2307 2200 7,984 2,02 1,27 523 30.9. 77,004 34,001 100 0,35 34,81 2301 2191 8,009 2,06 1,30 523 30.9. 77,004 34,001 74 -0,50 34,71 2297 2194 8,005 1,98 1,25 523 30.9. 77,004 34,001 50 -1,09 34,54 2288 2145 8,131 2,50 1,57 523 30.9. 77,004 34,001 30 3,20 34,07 2270 2091 8,158 3,05 1,92 523 30.9. 77,004 34,001 21 3,78 34,03 2270 2085 8,164 3,16 1,99 523 30.9. 77,004 34,001 9 4,01 34,01 2259 2066 8,183 3,29 2,07 522 30.9. 77,501 34,016 177 0,81 34,88 2303 2194 7,992 2,01 1,27 522 30.9. 77,501 34,016 150 0,54 34,82 2301 2191 8,004 2,04 1,29 522 30.9. 77,501 34,016 100 -1,41 34,61 2293 2188 8,027 1,99 1,25 522 30.9. 77,501 34,016 74 -1,55 34,57 2290 2183 8,035 2,02 1,27 522 30.9. 77,501 34,016 49 -1,21 34,49 2284 2154 8,101 2,34 1,47 522 30.9. 77,501 34,016 29 1,31 34,13 2274 2095 8,190 3,05 1,92 522 30.9. 77,501 34,016 9 2,80 33,35 2216 2045 8,162 2,94 1,85 521 30.9. 78,000 34,003 179 0,93 34,90 2303 2186 8,014 2,11 1,33 521 30.9. 78,000 34,003 149 1,00 34,89 2308 2185 8,030 2,20 1,39 521 30.9. 78,000 34,003 98 0,57 34,80 2308 2181 8,052 2,28 1,43 521 30.9. 78,000 34,003 74 -0,63 34,66 2293 2176 8,047 2,15 1,35 521 30.9. 78,000 34,003 49 -1,22 34,49 2291 2141 8,154 2,61 1,64 521 30.9. 78,000 34,003 29 0,65 34,21 2281 2088 8,230 3,24 2,03 521 30.9. 78,000 34,003 12 2,67 33,50 2228 2043 8,197 3,16 1,98 520 30.9. 78,505 33,989 168 1,32 34,94 2309 2192 8,007 2,12 1,34 520 30.9. 78,505 33,989 148 1,28 34,93 2312 2192 8,017 2,17 1,37 520 30.9. 78,505 33,989 99 0,64 34,81 2306 2173 8,068 2,36 1,48 520 30.9. 78,505 33,989 73 -0,56 34,69 2294 2169 8,070 2,26 1,42 520 30.9. 78,505 33,989 49 -1,10 34,52 2290 2153 8,114 2,42 1,52 520 30.9. 78,505 33,989 29 -0,65 34,43 2290 2115 8,208 2,98 1,87 520 30.9. 78,505 33,989 13 1,76 33,44 2207 2027 8,203 3,06 1,92 518 29.9. 79,003 33,984 254 -0,99 34,70 2297 2174 8,064 2,14 1,35 518 29.9. 79,003 33,984 199 -0,04 34,72 2303 2175 8,063 2,24 1,41 518 29.9. 79,003 33,984 99 -1,51 34,56 2287 2166 8,078 2,19 1,38 518 29.9. 79,003 33,984 73 -1,73 34,52 2287 2167 8,076 2,17 1,36 518 29.9. 79,003 33,984 50 -1,70 34,48 2287 2172 8,066 2,14 1,34 518 29.9. 79,003 33,984 29 -1,21 34,37 2282 2108 8,216 2,95 1,85 518 29.9. 79,003 33,984 9 0,13 32,64 2164 2004 8,194 2,75 1,72 516 29.9. 79,501 33,998 287 -1,57 34,79 2306 2181 8,076 2,14 1,35 516 29.9. 79,501 33,998 249 -0,70 34,74 2305 2176 8,074 2,22 1,40 516 29.9. 79,501 33,998 200 -0,02 34,72 2300 2174 8,059 2,22 1,40 516 29.9. 79,501 33,998 99 -0,69 34,62 2296 2175 8,061 2,20 1,38 516 29.9. 79,501 33,998 74 -1,51 34,53 2291 2165 8,091 2,27 1,42 516 29.9. 79,501 33,998 50 -1,37 34,48 2285 2151 8,112 2,38 1,49 516 29.9. 79,501 33,998 30 -1,02 34,34 2283 2124 8,177 2,75 1,72 516 29.9. 79,501 33,998 10 -0,89 32,79 2179 2005 8,244 2,95 1,84 514 29.9. 80,000 33,999 203 0,02 34,69 2296 2163 8,076 2,29 1,44 514 29.9. 80,000 33,999 149 0,01 34,68 2297 2168 8,069 2,28 1,43

99 Monitoring ocean acidification in Norwegian seas in 2017 | M-1072|2018

514 29.9. 80,000 33,999 123 -0,09 34,65 2291 2154 8,093 2,39 1,50 514 29.9. 80,000 33,999 99 -0,33 34,59 2294 2161 8,087 2,35 1,47 514 29.9. 80,000 33,999 74 -0,97 34,46 2286 2145 8,122 2,46 1,54 514 29.9. 80,000 33,999 49 -1,23 34,23 2269 2125 8,141 2,51 1,57 514 29.9. 80,000 33,999 29 -1,27 33,25 2198 2019 8,254 3,01 1,88 514 29.9. 80,000 33,999 20 -1,36 32,99 2189 2005 8,270 3,07 1,92 514 29.9. 80,000 33,999 10 -1,33 32,86 2184 2003 8,266 3,04 1,90 514 29.9. 80,000 33,999 4 -1,32 32,86 2189 2009 8,263 3,04 1,90 513 29.9. 80,497 33,996 159 0,20 34,66 2294 2163 8,070 2,29 1,44 513 29.9. 80,497 33,996 124 -0,21 34,61 2296 2162 8,087 2,35 1,48 513 29.9. 80,497 33,996 99 -0,92 34,47 2286 2151 8,104 2,36 1,48 513 29.9. 80,497 33,996 75 -1,17 34,35 2279 2140 8,126 2,44 1,53 513 29.9. 80,497 33,996 49 -1,14 34,16 2271 2125 8,147 2,55 1,60 513 29.9. 80,497 33,996 30 -0,85 33,52 2233 2066 8,209 2,85 1,79 513 29.9. 80,497 33,996 19 -0,50 33,22 2219 2039 8,241 3,05 1,91 513 29.9. 80,497 33,996 9 -0,76 32,89 2202 2031 8,232 2,93 1,83 513 29.9. 80,497 33,996 3 -0,91 32,77 2183 2011 8,240 2,93 1,83

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Table 11. Tromsø-Longyearbyen, 2017

T T 2 4 3 2 2 Date Lat Lon S T A C pHT pCO Ca Ar PO NO +NO SiO N E (C°) (µmol/kg) (µmol/kg) (µatm) (µmol/kg) (µmol/kg) (µmol/kg)

17.3 69.71 19.05 33.30 4.45 2253.1 2107.1 8.064 369 2.62 1.65 0.63 8.87 7.98 17.3 70.24 20.33 33.94 4.93 2277.4 2122.1 8.075 362 2.76 1.74 0.60 8.80 3.74 18.3 70.97 20.15 34.50 6.29 2298.6 2138.4 8.058 382 2.84 1.79 0.73 9.35 5.86 18.3 71.64 20.03 34.91 6.65 2313.7 2149.5 8.052 390 2.89 1.83 0.88 11.17 6.18 18.3 72.23 19.94 35.00 6.32 2315.9 2151.3 8.058 384 2.89 1.83 0.79 10.82 4.72 18.3 72.82 19.83 35.03 6.25 2318.8 2156.9 8.054 388 2.85 1.81 0.79 11.17 4.88 18.3 73.33 19.73 35.03 6.09 2314.9 2151.3 8.057 384 2.87 1.82 0.79 11.17 4.88 19.3 74.56 19.32 34.50 -0.06 2284.5 2163.0 8.064 366 2.25 1.41 0.69 9.01 4.55 19.3 75.30 17.80 34.83 2.85 2299.7 2161.9 8.065 370 2.49 1.57 0.79 10.40 5.04 19.3 75.88 16.65 35.01 4.92 2313.4 2156.5 8.064 376 2.77 1.75 0.79 11.17 4.55 19.3 76.35 14.81 34.69 5.59 2315.9 2151.4 8.061 381 2.89 1.83 0.82 11.17 5.04 19.3 76.91 13.93 34.95 6.36 2335.6 2161.2 8.050 395 3.04 1.93 0.79 10.82 4.88 20.3 77.47 13.19 34.97 7.43 2333.8 2161.0 8.033 414 3.03 1.92 0.79 10.82 5.04 20.3 78.02 13.15 34.97 6.68 * 2156.9 8.073 * * * 0.79 10.82 5.04 20.3 78.25 15.54 34.97 7.25 * 2154.3 8.086 * * * 0.76 10.19 5.04 12.5 69.73 19.05 33.52 5.40 2257.3 2062.2 8.177 275 3.34 2.10 0.25 0.49 1.79 12.5 69.90 18.70 33.48 4.66 2246.2 2069.5 8.156 290 3.06 1.92 0.28 1.75 1.63 13.5 70.96 16.64 34.61 7.00 2300.8 2128.3 8.076 365 3.02 1.91 0.54 6.49 2.93 13.5 71.48 15.67 34.71 6.89 2307.2 2130.3 8.088 354 3.08 1.95 0.57 6.77 3.42 13.5 72.22 14.81 34.95 6.62 2312.8 2139.6 8.078 364 3.02 1.91 0.66 8.86 4.23 13.5 72.82 14.58 34.91 6.83 2309.7 2143.1 8.070 372 2.92 1.85 0.69 9.21 4.39 13.5 73.32 14.33 34.97 6.53 2304.5 2147.3 8.074 366 2.78 1.76 0.73 9.42 4.88 14.5 74.61 13.64 35.02 6.15 2313.7 2149.3 8.066 376 2.88 1.82 0.85 10.40 7.64 14.5 75.39 13.24 35.02 6.32 2310.4 2154.4 8.063 377 2.77 1.75 0.88 10.82 7.48 14.5 75.89 13.03 35.03 5.86 2310.0 2154.7 8.067 373 2.75 1.74 0.82 10.82 6.02 14.5 76.37 12.74 35.02 5.87 2305.8 2157.3 8.066 374 2.66 1.68 0.82 10.82 6.02 14.5 76.89 12.49 35.02 5.79 2306.8 2153.2 8.069 371 2.73 1.73 0.76 10.47 4.72 14.5 77.77 12.64 34.68 3.25 2300.2 2047.0 8.313 192 4.17 2.62 0.25 1.26 0.94 14.5 78.00 13.11 34.38 1.13 2238.6 2045.5 8.340 174 3.23 2.03 0.22 0.84 0.75 14.5 78.26 15.39 34.38 1.52 2281.7 2053.8 8.301 197 3.77 2.37 0.22 0.42 0.78 4.8 69.72 19.06 31.89 11.17 2142.6 1949.5 8.099 329 3.35 2.12 0.22 0.35 1.55 4.8 70.24 20.30 33.37 11.08 2237.0 2023.4 8.111 329 3.66 2.33 0.25 0.56 0.90 4.8 70.95 19.74 34.28 11.30 2283.0 2055.9 8.114 331 3.86 2.46 0.25 0.35 0.63 5.8 71.65 19.02 34.38 11.08 2310.6 2071.5 8.127 323 4.06 2.58 0.22 0.42 0.72 5.8 72.21 18.36 34.75 10.45 2321.2 2084.0 8.138 314 4.01 2.55 0.22 0.35 0.63 5.8 72.81 17.67 34.62 10.69 2319.5 2074.6 8.144 309 4.13 2.63 0.22 0.28 0.57 5.8 73.32 17.06 34.80 9.99 2318.9 2093.0 8.127 323 3.83 2.44 0.25 0.98 0.73 5.8 74.54 15.53 34.72 10.51 2315.0 2075.6 8.150 303 4.04 2.57 0.19 0.28 0.54 5.8 75.28 14.51 34.65 10.03 2314.8 2090.6 8.129 321 3.81 2.42 0.22 0.28 0.63 6.8 75.89 14.12 34.73 10.02 2321.5 2088.5 8.135 317 3.94 2.51 0.22 0.28 0.68 6.8 76.39 13.91 34.83 9.77 2320.5 2091.4 8.141 311 3.88 2.46 0.22 0.42 0.60 6.8 76.95 13.62 34.11 7.93 2264.5 2040.9 8.191 266 3.77 2.39 0.22 0.21 0.60 6.8 77.19 13.51 33.29 8.02 2228.4 2010.1 8.181 270 3.70 2.34 0.19 0.28 0.67 6.8 78.00 13.12 33.35 8.47 2237.5 2015.5 8.167 282 3.76 2.38 0.19 0.28 0.83

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6.8 78.26 15.42 30.80 9.89 1842.7 1687.3 8.129 262 2.61 1.64 0.16 0.42 7.50 11.11 78.25 15.57 34.43 6.52 2292.3 2125.1 8.065 375 2.93 1.86 0.60 6.49 3.58 12.11 78.09 13.32 34.14 4.60 2275.8 2108.3 8.099 339 2.92 1.84 0.47 5.31 2.60 12.11 77.49 13.47 34.32 4.02 2278.6 2120.0 8.085 351 2.79 1.76 0.51 5.17 2.44 12.11 76.97 13.99 34.26 3.02 2276.1 2124.5 8.098 338 2.68 1.69 0.54 5.87 2.77 12.11 76.36 14.52 34.86 5.58 2308.8 2139.6 8.083 358 2.95 1.86 0.66 8.72 3.58 13.11 75.86 14.96 34.85 6.57 2311.1 2141.2 8.065 377 2.98 1.88 0.25 9.56 10.08 13.11 75.27 15.87 34.80 5.98 * 2141.3 8.070 * * * 0.41 2.65 3.74 13.11 74.53 16.68 34.84 6.09 2309.7 * 8.071 370 * * 0.63 8.52 3.42 13.11 73.33 17.81 34.87 7.33 2315.3 2136.8 8.067 376 3.10 1.97 0.63 8.38 3.42 13.11 72.84 18.25 34.78 8.02 2310.6 2127.8 8.073 371 3.17 2.01 0.54 6.49 2.60 13.11 72.22 18.81 34.49 8.62 2303.9 2119.9 8.074 370 3.20 2.03 0.47 5.52 2.28 14.11 71.64 19.28 34.62 8.61 2310.5 2122.3 8.068 376 3.26 2.07 0.50 6.00 2.44 14.11 70.94 19.90 33.92 9.68 2280.8 2094.5 8.070 372 3.25 2.06 0.35 3.63 1.95 14.11 70.28 20.36 33.53 9.76 * 2083.4 8.071 * * * 0.32 3.07 1.79 14.11 69.72 19.05 32.84 7.90 2221.0 2065.0 8.052 381 2.79 1.76 0.44 4.40 3.91

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Table 12. Oslo-Kiel, 2017.

T T 2 4 3 2 2 Date Lat Lon S T A C pHT pCO Ca Ar PO NO +NO SiO N E (C°) (µmol/kg) (µmol/kg) (µatm) (µmol/kg) (µmol/kg) (µmol/kg)

16.1 59.82 10.58 29.54 2.61 2113.5 2002.0 7.921 505 2.13 1.32 0.92 18.22 21.06 16.1 59.20 10.63 31.02 5.11 2167.6 2043.6 8.034 390 2.33 1.46 0.60 8.54 10.11 16.1 59.00 10.68 31.09 4.36 * 2059.7 8.073 * * * 0.57 6.44 9.79 16.1 58.85 10.73 31.15 4.50 2236.4 2097.1 8.075 362 2.58 1.61 0.57 4.90 8.32 16.1 58.65 10.80 31.33 4.18 2264.1 2095.6 8.070 371 3.01 1.88 0.57 4.27 7.50 16.1 58.45 10.87 30.58 3.73 2242.2 2110.9 8.073 365 2.47 1.54 0.60 4.69 9.30 16.1 58.25 10.97 29.78 3.26 2219.4 2097.5 8.076 361 2.34 1.46 0.57 4.48 9.80 16.1 58.05 11.06 28.43 2.69 2190.6 2077.3 8.077 359 2.23 1.38 0.57 4.14 9.64 16.1 57.85 11.15 26.06 2.52 2131.6 2017.2 8.060 372 2.26 1.38 0.57 4.50 10.15 6.5 59.82 10.59 24.29 11.94 1914.7 1693.8 8.328 172 3.97 2.45 0.48 0.42 11.15 6.5 59.20 10.63 25.76 11.27 2081.9 1951.9 8.045 391 2.57 1.59 0.13 0.28 5.40 6.5 59.00 10.64 24.66 11.19 2113.7 1992.2 8.040 408 2.49 1.53 0.16 0.14 4.75 6.5 58.85 10.64 23.92 11.40 2093.5 1977.9 8.029 419 2.41 1.48 0.16 0.14 4.43 6.5 58.65 10.64 22.90 10.87 2067.2 1963.0 8.035 412 2.24 1.37 0.13 0.14 3.77 6.5 58.45 10.64 22.70 11.22 2065.8 1965.6 8.027 421 2.19 1.34 0.16 0.14 4.43 6.5 58.25 10.72 32.60 10.18 2249.2 2075.6 8.090 351 3.10 1.96 0.19 0.14 1.95 6.5 58.05 10.90 24.12 9.83 2107.2 1989.9 8.070 377 2.42 1.48 0.16 0.07 4.10 6.5 57.85 11.06 22.25 10.72 2056.8 1957.1 8.030 419 2.18 1.33 0.16 0.07 3.94 29.7 59.82 10.58 23.34 18.84 1798.5 1638.4 8.098 307 3.04 1.89 0.41 0.35 4.76 29.7 59.20 10.63 24.68 18.74 1922.1 1755.9 8.069 349 3.17 1.99 0.16 0.21 1.41 29.7 59.00 10.62 25.24 18.87 1915.1 1746.4 8.075 339 3.18 2.00 0.22 0.21 1.05 29.7 58.85 10.62 23.99 17.50 2058.1 1925.1 8.024 424 2.74 1.71 0.16 0.14 1.28 29.7 58.65 10.62 23.82 17.07 2077.8 1940.3 8.008 447 2.82 1.75 0.19 0.14 1.97 29.7 58.45 10.66 31.95 16.77 2227.7 2032.1 8.030 414 3.52 2.25 0.13 0.14 0.00 29.7 58.25 10.83 32.37 16.57 2240.4 2042.2 8.036 408 3.55 2.27 0.16 0.14 0.54 29.7 58.05 10.99 32.06 16.87 2239.1 2042.6 8.029 417 3.54 2.27 0.16 0.14 0.59 29.7 57.85 11.14 27.05 16.70 2141.2 1970.7 8.013 437 3.23 2.04 0.06 0.21 74.92 2.11 59.82 10.59 22.53 8.36 1845.1 1773.8 7.938 466 1.61 0.98 0.25 9.51 10.01 2.11 59.20 10.63 25.80 10.06 2014.6 1886.8 8.023 398 2.47 1.53 0.35 4.99 7.70 2.11 59.00 10.63 26.03 10.99 2159.5 2008.0 8.053 396 2.93 1.82 0.38 1.83 3.93 2.11 58.85 10.64 26.17 10.64 2170.9 2010.7 8.075 376 3.07 1.90 0.35 0.98 3.11 2.11 58.65 10.63 26.31 10.90 2169.1 2011.7 8.065 385 3.02 1.88 0.35 1.33 3.27 2.11 58.45 10.63 31.16 13.12 2318.9 2119.5 8.047 413 3.61 2.29 0.66 8.61 3.59 2.11 58.25 10.78 30.47 12.56 2300.7 2111.8 8.044 416 3.46 2.19 0.44 0.98 3.59 2.11 58.05 10.92 30.30 12.35 2300.7 2108.2 8.048 412 3.52 2.23 0.41 0.91 3.43 2.11 57.85 11.09 29.77 12.14 2305.8 2120.2 8.045 417 3.43 2.17 0.51 1.40 5.71

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Table 13. Cold water coral reefs, 2017.

Date Stn Depth S T AT CT pHT Ca Ar NO3 PO4 SiOH4 (m) (C°) (µmol kg-1) (µmol kg-1) (µmol/kg) (µmol/kg) (µmol/kg)

15.8. Hesteneset 10 31,38 15,49 2239 2040 8,051 3,59 2,29 0,00 0,78 5,7 15.8. Hesteneset 50 32,82 11,04 2262 2099 8,011 2,93 1,86 0,00 0,82 6,2 15.8. Hesteneset 100 34,23 8,36 2304 2164 7,971 2,55 1,62 0,00 0,73 5,3 15.8. Hesteneset 150 34,70 7,97 2316 2177 7,968 2,51 1,59 0,16 0,29 1,6 15.8. Hesteneset 200 34,84 7,80 2321 2179 7,972 2,51 1,59 0,11 0,00 0,0 15.8. Straumsneset 10 31,60 15,49 2238 2043 8,038 3,52 2,24 0,00 0,76 5,6 15.8. Straumsneset 50 32,94 11,27 2266 2102 8,008 2,95 1,87 0,00 0,80 6,0 15.8. Straumsneset 100 34,39 8,36 2304 2162 7,977 2,58 1,64 0,00 0,70 5,2 15.8. Straumsneset 150 34,96 7,98 2313 2176 7,958 2,46 1,56 0,16 0,31 1,7 15.8. Straumsneset 200 35,02 7,80 2316 2171 7,980 2,55 1,62 0,14 0,00 0,0 17.8. Huglhammaren 10 28,78 15,48 2140 1953 8,072 3,43 2,17 0,00 0,78 5,9 17.8. Huglhammaren 50 32,90 10,46 2257 2095 8,016 2,90 1,84 0,00 0,83 6,3 17.8. Huglhammaren 100 34,29 8,26 2306 2167 7,969 2,53 1,61 0,00 0,77 5,6 17.8. Huglhammaren 150 34,59 8,05 2312 2178 7,955 2,44 1,55 0,12 0,28 1,3 17.8. Huglhammaren 200 34,72 7,91 2300 2159 7,971 2,49 1,58 0,06 0,00 0,0 17.8. Hornaneset 10 29,13 15,42 2069 1882 8,080 3,38 2,14 0,00 0,77 5,9 17.8. Hornaneset 50 33,29 10,17 2268 2111 8,002 2,82 1,79 0,00 0,81 6,2 17.8. Hornaneset 100 34,58 8,28 2304 2166 7,964 2,52 1,60 0,00 0,72 5,3 17.8. Hornaneset 150 34,95 7,99 2313 2179 7,952 2,44 1,55 0,09 0,37 2,0 17.8. Hornaneset 200 35,10 7,86 2317 2170 7,984 2,58 1,64 0,00 0,16 0,0

6.3 Definitions

- 2- - - 2- 3- - - AT = [HCO3 ] + 2[CO3 ] + [B(OH)4 ] + [OH ]+[HPO4 ] + 2[PO4 ] + [SiO(OH)3 ] + [NH3 ] + [HS ] - + - - [H ] - [HSO4 ] + [HF ] + [H3 PO4] -…..

(4)

- 2- CT = [CO2*] + [HCO3 ] + [CO3 ] (5)

+ + - [H ] ~ [H ]f +[HSO4 ], + der [H ]f er den frie hydrogenkonsentrasjonen pH = -log10 ([H+]) (6)

pCO2 = [CO2*]/K0 (7)

104

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