Dorinda Ostermann (W.H.O.I., Woods Hole, MA 02543; [email protected]), William B. Curry (W.H.O.I., Woods Hole, MA 02543),Susumu Honjo (W.H.O.I., Woods Hole, MA 02543), Jon Olafsson (Marine Research Institute, Reykjavik; [email protected]),Steven J. Manganini (W.H.O.I., Woods Hole, MA 02543; [email protected])

G. quinqueloba N. pachyderma N. pachyderma The Greenland, and Norwegian Seas (GIN) together form 0.5 0-200 Meter Data dextral (R) sinistral (L) W) a high latitudeegion r with waters of both and North Atlantic 18 Iceland Sea Water Temperature (°C), 1986-1999 (SMO Relationship between salinity (psu) and δtheO (SMOW) origin mix. The GIN Seas have also beenecognized r as critical to 86 87 88 89 90 91 92 93 94 95 96 97 98 99 content of the upper 200 meters of wateround ar Iceland 0 8.8

water based upon Geosecs (> 60°N) and water collected oundar the formation of North Atlantic Deep water (NADW) whoseoduc- pr O

18 0.0 Iceland by D.R. Ostermann and extracted and measured

-50 δ Location of sediment trap mooring at Harvard University by D. Schrag. tion has been linked to the heat balance associated with the Global ° (68°N, 12.6°W) indicated by Geosecs >60 N -100 Iceland Plateau 1995 & 1997 Conveyor circulation system. The Iceland Sea sediment trap was yellow star, showing basin and West Iceland (64.3°N 28.8°W) bottom topography. ater Depth (m) 2.0 ° ° deployed to monitor the particle fluxesponse r to decadal changes W -150 East Iceland (64.5 N 6 W) 1.0 Time series temperature and salinity profiles -0.5 0.0 in local and egionalr hydrographic conditions and to interpret down- of the upper 200 meters of water at the 34.0 34.5 35.0 35.5 -200 -1.2 Iceland Sea Oxygen Isotopes, 1994-1996.5 mooring location. This figure is based upon Salinity (psu) Iceland Sea Salinity (psu), 1986-1999 AVHRR satellite sea surface temperature 2 core N. pachyderma and G. quinqueloba flux and stable isotope 86 87 88 89 90 91 92 93 94 95 96 97 98 99 data and data omfr at least four hydro- 0 34.94 records on glacial to interglacial time scales. graphic bottle casts during each year (data The blue line in each panel at right shows the 34.85 18 3 from the M.R.I., Reykjavik, Iceland). Note average equilibrium calciteδ O of the surface At the Iceland Sea mooring location, in-situ and satellite derived -50 34.79 temperature data and measured δ18O (SMOW) 34.74 the deepening of theesher fr water lens 34.70 data from the panel above. Theed r line in each

g (data as collected) 18 sea surface temperature (SST) data show clear interannual oscilla- 34.64 during the years beginning in 1996. 4 Calcite δ O -100 We speculate that this may indicate a panel is the average 150-250µm G. quinqueloba G. quinqueloba δ18O

isotopic measurements. The upper panel shows No La tions between cold and warm periods which havefected af the ater Depth (m) deepening of the surface mixed layer

Location of Iceland Sea Sediment Trap Mooring, 1986 – present W -150 providing greater nutrient availability. The that foraminiferans ear almost 180 degrees out of 2 phase with the equilibriumδ18 O. This means that planktonic foraminiferal faunal assemblage and stable isotopic data. 60 bottom figure shows the foraminiferal flux ˚W ˚ E 34.29 the shells were calcified almost 6 months prior to Current diagram showing water 60 30 -200 lagged by 14 days. The width of each bar These dramatic temperature oscillations do not directly affect the ˚W 3 ˚E deposition into the sediment trap. A 6 month "lag" masses affecting the mixture of 30 Year indicates the sampling interval which was g (6 months)

water at trap location. -1 86 87 88 89 90 91 92 93 94 95 96 97 98 99 shows foraminifers calcifying in enriched waters timing and magnitude of the peak foraminiferal flux (>µ m125

usually~27 days. Although rare, N. pachy- La ˚N y 10000 Shells Calcifying 80 well before the temperature actually begins to 4 out of equilibrium? 70 da derma dextral (R) occurs at the same time T Iceland Sea Foraminiferal Flux, 1986-1999 2 -1 N Lag too big... Max. E 2 individual foraminiferal tests m day ) which have been ˚ N R warm up, not likely to happen under normal ocean- R as N. pachyderma sinistral (L) at this U C D 8000 ographic conditions. With a "lag" of 3 months,G. N A location. L documented to occur in almost any month at this location. N 2 E quinqueloba data are brought into phase with the E R G GREENLAND . Greenland E Greenland surfaceδ 18O. G. quinqueloba was used to set the Sea 6000 The 1998-1999 collection interval clearly shows an earlier and

T N lag because as a surface dweller, its shell chemistry E 3 Labrador R

R g (3 months)

Sea U 18 LABRADOR Sea C exhibits a strong seasonal sea surfaceδ O signal greatly intensified spring bloom, more typical of the North Atlantic

C 4000

I

D N

m individual tests m (see panel below). A Shells Calcifying

µ L

E in equilibrium than the summer and fall blooms of the Iceland Sea. Although the C 4

NEWFOUNDLAND I Norwegian .

E Sea 2000 Optimal La T foraminiferal faunal assemblages contain similar species during the N E R 94.0 94.5 95.0 95.5 96.0 96.5 R Flux >125 Year C U N entire 1986-1999 collection interval, the foraminiferal flux collected 50 IA ˚ EG 60˚N µ N W Peak >125 m Foraminiferal Flux O R G. quinqueloba N. pachyderma(R) N. pachyderma(L) N tests/m2/day during 1998-1999 is more indicative of a North Atlantic bloom sig-

N 0 4000 8000 12000 16000 O R 125-150 125-150 125-150 T H nature. Olafsson et al. (see poster to the left) documenteatly a gr AT L N T North Denmark Strait A N T IC C U R R E IRELAND 40 150-250 150-250 150-250 ˚N Iceland Sea 1986-1997 increased total particulate flux for this interval. These particle fluxes 13 glass balls Modified from McCartney et al., 1996. Oceanus, vol. 39(2). A compilation of foraminiferal fluxesom fr sedi- Iceland Sea 1998-1999 for flotation may correlate with a westerly inflow of warmer nutrient-rich Atlantic ment traps deployed oundar the world. Iceland South Iceland G. quinq ueloba 3 Month Lag N. pachyderma Left & Right 3 Month Lag 91 cm dia. 2 2 Sea peak fluxes were averaged from 1986-1997 JGOFS 47 North water north of Iceland. and presented separately omfr the 1998-1999 JGOFS 34 North deployment interval. The 1998-1999 Iceland Sea Stable isotopic data indicate that the foraminiferans at the 1423 Sea of Okhotsk mbs peak foraminiferal fluxese ar similar in magnitude Iceland Sea mooring locatione arliving for 3-6 months. They make to some of the most oductivepr areas of the world Western Arabian Sea (eg. Arabian Sea, Curry et al., 1992 & Sea of Central Arabian Sea 3 3 their shells in isotopically enriched waters andeproduce, r die and Okhotsk, Alderman, 1996). Eastern Arabian Sea

O (PDB) settle into the sediment trap 3-6 months .later Poulain et al. North Bay of Bengal 18 δ Side View detail of Central Bay of Bengal (1996) show the mooring location to be in anea arof low near- Mk 7-13 Sediment trap Antarctic peninsula surface current velocities and we believe that the oxygen isotopic 152 cm 4 4 Iceland Sea Foraminiferal Weight Flux, 1986-1999 signature of G. quinqueloba indicates in-situ calcification and not Mk 7-13 -1 y 70 Sediment calcification in waters to the south or north with subsequent trans- da Trap C M 2 60 86 87 88 89 90 91 92 93 94 95 96 97 98 99 86 87 88 89 90 91 92 93 94 95 96 97 98 99 port to the mooring location, and deposition into the sediment trap. Year Year g m

µ 50 G. quinqueloba oxygen isotopic data plotted with- sur N. pachyderma oxygen isotopic data plotted with- sur The use of stable isotopic analyses allows us toectly corr identify face water equilibrium calcite (black line). This speciesface (black line) and 40 meter (orange line) equilibrium 40 is a surface dweller and show aong str seasonal signal, calciteδ 180. This species is a subsurface dweller, living the timing of foraminiferal calcification. with the 125-150µ m individuals living slightly deeper at or near 40 meters during the entire year. 30 than the individuals in the 150-250µm fraction. eight Flux

W References: 430 20 m

mab µ 1 10 Alderman, S.E. 1996. Planktonic Foraminifera in the Sea of Okhotsk: Water Masses around Iceland Sea 0 Population and Stable Isotopic Analysisom fr a Sedimentrap. T M.I.T./ 125-150 (61°N 27°W) 86 87 88 89 90 91 92 93 94 95 96 97 98 99 0 10 -1 70 W.H.O.I. Joint Program in Oceanography, Masters Thesis. pp. 1-99. y Benthos Norwegian Current (68°N 5°W) da C (PDB)

Acoustic 2 60 13 Release 8 δ -1 Curry, W.B., D.R. Ostermann, M.V.S. Guptha and .V Ittekkot. 1992.

g m 50 µ Foraminiferal production and monsoonal upwelling in the Arabian Sea: 1000 kg Anchor 40

C) N. pachyderma & G. quinqueloba 3 Month Lag ° 6 evidence from sediment traps.Fr om Summerhayes, C.P., Prell, W.L. -2 Diagram of mooring at Iceland East Icelandic Current 30 (IP location) 86 87 88 89 90 91 92 93 94 95 96 97 98 99 & Emeis, K.C. (eds.),Upwelling Systems: Evolution Since the early eight Flux Year W 20 G. quinqueloba and N. pachyderma carbon isotopic data. The lines indicate the average values for each species Miocene. Geological Society Special Publication No. 64, pp. 93-106. 4 m µ and size fraction. TheN. pachyderma sinistal and dextralδ13 C indicate that these deeper dwelling foraminifers

emperature ( 10

T are living in depleted water compared to the more surface dwellingG. quinqueloba where there is a 0.28 per mil difference between the average 125-150µm δ13C and the average 150-250µm δ13C. TheG. quinqueloba δ13C 2 0 McCartney, M.S., R.G. Curry and Hu.F. Bezdek, 1996. North Atlantic's 150-250 86 87 88 89 90 91 92 93 94 95 96 97 98 99 has shown a small but detectable change over the collection interval as well. These changes don't account for Transformation Pipeline Chills and Redistributes Subtropical Water. Temperature/Salinity diagrams of (72°N 20°W) Year the large species and weight flux changes over the same intervals. water masses at and near the Foraminiferal weight flux lagged by 14 days. Note that the 125-150G. quinqueloba weight flux is approximately Oceanus, vol. 39, no. 2, pp. 19-23. mooring location showing that0 equal to the 150-250 weight fluxN. of pachyderma sinistral (L), and that all weight fluxes dramaticallyease incr the mooring site water is a mixture during the 1998 collection interval. of North Atlantic Current, Summary: Stefansson, U. and Jon Olafsson. 1991. Nutrients and fertility of Norwegian Current and -2 East Greenland Current waters. 33.5 34.0 34.5 35.0 35.5 Summary: Given the trap depth and typical foraminifer settling velocites of Icelandic waters. J. Marine Res. Inst., Reykjavik. pp. 1-56. Salinity (psu) Temperature and salinity data alone do not uniquely constrain the about 100 m day-1, individual tests would be expected to settle into large species and weight flux variability of planktonic foraminifera at the sediment trap within 14 days. Based on comparisons to water Poulain, P.-M., A. Warn-Varnas and .PP. Niiler. 1996. Near-surface the Iceland Sea mooring location. Quarterly ographichydr data may temperature and chemistry, we found that the date of deposition into circulation of the Nordic seas as measured by Lagrangian drifters. J. the sediment trap was significantly delayed up to 3-6 monthsom fr Geophysical Res., vol. 101. no. C8, pp. 18,237-18,258. Mean velocity vectors corrected (open arrows) and not also bias theecor r ds by missing unique, short lived hydrographic corrected (solid arrows) for the "array" bias. Statisticse ar phenomena. It is clear that the foraminiferal assemblage, although the probable date of shell calicification. Stable isotopic analyses of computed from combined drogued and wind corrected undrogued drifter observations (Aug. 1991–Dec. 1994). constant in species composition, shows dramatic changes over near-surface dwellingG. quinqueloba allow us to shift or lag the The mooring location (yellow star) straddles the boundaries between the Polar and Arcticonts Fr within a weak cyclonic decadal time scales in numbers and weight. These changes will deposition dates to the calicification dates by 3 months and align gyre of low near-surface current velocities (Poulain et al., isotopically depleted values G.of quinqueloba to the warmest SST's 1996). certainly affect the number of shellseserved pr in the sediment during unique production pulses such as the 1998 collection interval. and chemistries and enriched values to the coldest SST's and chemistries.G. quinqueloba δ13C depletion in 1998-1999 maybe be a response to the stripping of nutrients following the elevated production during these years. Poster design by WHOI Graphic Services