Ocean Carbon & Biogeochemistry meeting, June 27

Recent changes in phytoplankton productivity and phenology in the Arctic Ocean

Mathieu Ardyna Marie Skłodowska-Curie Fellow Stanford University/Sorbonne Université LOSS IN SEA-ICE COVER IN SEPTEMBER

Russia 8 )

1996 2 7

Alaska km 6 6 2012 5

Greenland Extent (10 4 Canada 3

1980 1988 1996 2004 2012

Year

NSIDC (2017) LOSS IN MULTIYEAR SEA-ICE

March 1990 March 2016

1 2 3 4 5 6 7 8 9 >9 Sea-ice age (years)

NOAA (2016) EARLIER BREAKUP & DELAYED FREEZE-UP

Breakup Freeze-up

1998-2013

Unpublished data EARLIER BREAKUP & DELAYED FREEZE-UP

Breakup Freeze-up

Kara Sea

Barents Sea

1998-2013

Unpublished data THE KEY FEATURES IN PHYTOPLANKTON PHENOLOGY

Phenology, the study of annually recurring life cycle events, can provide particularly sensitive indicators of climate change.

Wassmann & Reigstad (2011) THE KEY FEATURES IN PHYTOPLANKTON PHENOLOGY

- Break-up and freeze-up time that determine the duration of the open-water period - Seasonal light cycle - Properties of the snow-ice system - Nutrient dynamics - Top-down control

Wassmann & Reigstad (2011) ONGOING CHANGES IN PHYTOPLANKTON PHENOLOGY

Present Future

Wassmann & Reigstad (2011) ONGOING CHANGES IN PHYTOPLANKTON PHENOLOGY

Present Future

Key satellite-derived findings (2011- now):

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom

Wassmann & Reigstad (2011) EARLIER SPRING BLOOM IN THE SEASONAL ICE ZONE

Foxe Basin

250

200 Key satellite-derived 22 18 findings (2011- now): 150

14 Day length (h) Day of the year 100 10 300 Earlier spring bloom in Baffin Bay 24 the seasonal ice zone 250 20

More intense bloom at 16 high latitude 200 12 Day length (h) Day of the year Decrease production at 150 8 low latitude 1996 1998 2000 2002 2004 2006 2008 2010 Year Increasing occurrence of fall bloom => Due to early sea-ice break-up

Kahru et al. (2010) ONGOING CHANGES IN PHYTOPLANKTON PHENOLOGY

Present Future

Key satellite-derived findings (2011- now):

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom

Wassmann & Reigstad (2011) MORE INTENSE BLOOM AT HIGH LATITUDE

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude

20 30 50 60 70 Increasing occurrence -30 -20 -10 0 10 40 of fall bloom Annual increase in primary production of the spring bloom (mg C m-2 d-1 y-1)

Renaut et al. (sub.) MORE INTENSE BLOOM AT HIGH LATITUDE

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude

-2 -1.5 -1 -0.5 0 0.5 1 1.5 2 =>Increasing Due to occurrenceincreasing light intensityof fall bloom during Annual increase in PAR during the spring -2 -1 -1 the bloom period bloom (mol photon m d y )

Renaut et al. (sub.) ONGOING CHANGES IN PHYTOPLANKTON PHENOLOGY

Present Future

Key satellite-derived findings (2011- now):

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom

Wassmann & Reigstad (2011) DECREASE PRODUCTION AT LOW LATITUDE

Inflow shelves

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom => Due to increasing thermal stratification (and stronger nutrient limitation?) in inflow shelves

Pabi et al. (2008), Bélanger et al. (2013), Arrigo and van Dijken (2015) FAVORING POLEWARD SHIFT OF COCCOLITOPHORE BLOOMS

Inflow shelf: Barents Sea

Oziel et al. (2017, 2018), Neukermans et al. (2018) FAVORING POLEWARD SHIFT OF COCCOLITOPHORE BLOOMS

1998 2012 Particulate Inorganic Carbon

Oziel et al. (2017, 2018), Neukermans et al. (2018) FAVORING POLEWARD SHIFT OF COCCOLITOPHORE BLOOMS

1998 2012 Particulate Inorganic Carbon

Sea Surface Temperature Increased intrusion of warm Atlantic water leads to the expansion of coccolithophore blooms in the Arctic

Oziel et al. (2017, 2018), Neukermans et al. (2018) ONGOING CHANGES IN PHYTOPLANKTON PHENOLOGY

Present Future

Key satellite-derived findings (2011- now):

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom

Wassmann & Reigstad (2011) INCREASING OCCURRENCE OF FALL BLOOMS

Earlier spring bloom in the seasonal ice zone More intense bloom at high latitude Decrease production at low latitude Increasing occurrence of fall bloom

Ardyna et al. (2014), SWIPA (2017) Trend in number of fall stormy days over open water

INCREASING OCCURRENCE OF FALL BLOOMS

150°E 180° TrendTrend in number in number of fall of fall 90°E stormy days over 60°E 120°E

stormy days over 150°W 120°E -1 open water day year open water 1 30°E 0.8 150°E

90°E 0.6 120°W 0.4 Earlier spring bloom in 0.2

the seasonal ice zone 0° 0 180°

60°E −0.2

90°W More intense bloom at −0.4 high latitude −0.6 150°W

30°W −0.8 30°E Decrease production at −1 low latitude 60°W day year

120°W

1 0° 60°W 0.8 0.6 30°W 90°W -1 Increasing occurrence 0.4 0.2 0 of fall bloom −0.2 −0.4 => Due to both more−0.6 storms and −0.8 more sea−1 -ice free areas

Ardyna et al. (2014), SWIPA (2017) CHANGING ARCTIC PARADIGMS

To the “borealization” of the Arctic Ocean:

Ardyna (2013,2015), Wassmann & Reigstad (2011) MASSIVE UNDER SEA-ICE BLOOMS: UNDETECTABLE BY SATELLITE

Melt-ponded sea ice

Phytoplankton bloom beneath ponded-ice due to increased Under-ice bloom light transmittance.

The highest values reach up 30 mg Chl m-3 and dominated by centric diatoms.

Arrigo et al. (2012, 2014) MASSIVE UNDER SEA-ICE BLOOMS: PAN-ARCTIC DISTRIBUTION ?

In the Chukchi Sea captured by Ice-Tethered Profilers.

Hill et al. (2017) MASSIVE UNDER SEA-ICE BLOOMS: PAN-ARCTIC DISTRIBUTION ?

North of Svalbard: N-ICE program In the Chukchi Sea captured by Ice-Tethered Profilers.

7 ) 3 6 - 5 82°N 4 3 0 81°N 2 50 1 Chlorophyll (mg m 100 Depth (m) Depth 3°E 9°E 15°E 0

Hill et al. (2017) Assmy et al. (2017) CHANGING ARCTIC PARADIGMS

To an uncertain future for the sea-ice algae and under-ice phytoplankton blooms

Ardyna (2015), Wasmman & Reigstad (2011) CAP-ICE: MARIE SKLODOWSKA-CURIE FELLOWSHIP

The primary objectives are to:

(i) Determine the spatial importance of under-ice blooms in the Arctic Ocean. CAP-ICE: MARIE SKLODOWSKA-CURIE FELLOWSHIP

The primary objectives are to:

(i) Determine the spatial importance of under-ice blooms in the Arctic Ocean.

(ii) Reveal the environmental drivers of the initiation, magnitude and structure CAP-ICE: MARIE SKLODOWSKA-CURIE FELLOWSHIP

The primary objectives are to:

(i) Determine the spatial importance of under-ice blooms in the Arctic Ocean.

(ii) Reveal the environmental drivers of the initiation, magnitude and structure

(iii) Upscale their survey and predict their occurrence by combining autonomous platforms and satellite PAN-ARCTIC CONSORTIUM: EXPEDITION & SEA-ICE CAMPS

Ardyna et al. (In prep.) SubIce Icescape

30

10

20

5 SubIce Icescape 10

0 0 30 mai 19 mai 26 jui 02 jui 09 jui 16 jui 21 jui 28 jul 05 jul 12 GE SIC 2015 GE SIC 2016

10 ) Algal group −3 7.5 2.0 Chlorophytes 20 Chryso−Pelago 1.5 Cryptophytes 5.0 Diatoms yll a (mg m

DIATOM VERSUS PHAEOCYSTIS UNDERh -ICE BLOOMS Dinoflagellates 1.0 Haptophyte−7 5 2.5 Phaeocystis 0.5

10 Chlorop Prasinophyte−2 Prasinophyte−3 Phaeocystis under-ice0.0 blooms 0.0 avr mai jui jul mai jui jul N-ICE GreenGE Amundsen Edge N-ICE 3) 0 - 0 3 3 jui 21 jui 28 jul 05 jul 12 mai 19 mai 26 jui 02 jui 09 jui 16 1010 GE SIC 2015 2 GE SIC 2016 2 5 ) 5 1 Algal group −3 1 7.5 2.0 Chlorophytes 0 0 00 Chryso−Pelago Feb Mar Apr May Jun jui 13 jui 20 jui 27 jul 04 jul 11 fév mar avr mai jui

Chlorophyll a (mg m 1.5 Jul4 Date Cryptophytes Jun13 Jun20 Jun27 Jul12 5.0 Diatoms yll a (mg m

h Diatom under-ice blooms Dinoflagellates 1.0

3) SUBICESubIceSubIce ICESCAPEIcescapeIcescape Haptophyte−7 - 2.5 303030 Phaeocystis 0.5 10 10 Chlorop 10 Prasinophyte−2 20 2020 Prasinophyte−3 0.0 0.0 55 5 avr mai jui jul mai 101010jui jul

GE Amundsen 00 0 0 00N-ICE mai 19mai 19mai 26mai 26jui 02jui 02jui 09jui 09jui 16jui 16 jui 21jui 21 jui 28jui 28 jul 05jul 05 jul 12jul 12 Chlorophyll a (mg m GEJun2GE SIC SIC 2015Jun9 2015 GEGE SIC SIC 2016Jul5 2016 Mai19 Mai26 Jun16 Jun21 Jun28 Jul12 ) ) 3 Algal group

−3 Algal group −3 7.5 7.5 2.0 2.0 ArdynaChloropChloropethytes al.hytes (In prep.) 10 Chryso−Chryso−PelagoPelago

1.5 1.5 CryptopCryptophyteshytes 5.0 5.0 DiatomsDiatoms yll a (mg m yll a (mg m h h 2 DinoflagellatesDinoflagellates 1.0 1.0 HaptopHaptophyte−7hyte−7 2.5 2.5 PhaeocystisPhaeocystis 0.5 0.5 Chlorop 5 Chlorop PrasinopPrasinophyte−2hyte−2 PrasinopPrasinophyte−3hyte−3 0.0 0.0 1 0.0 0.0 avr avr mai mai jui jui jul jul mai mai jui jui jul jul GEGE Amundsen Amundsen N-ICEN-ICE

3 3

0 10 10 0 fév mar avr mai jui jui 13 jui 20 jui 27 jul 04 jul 11 2 2

5 5 Date 1 1

0 0 0 0 jui 13jui 13 jui 20jui 20 jui 27jui 27 jul 04jul 04 jul 11jul 11 fév fév mar mar avr avr mai mai jui jui DateDate DIATOM VERSUS PHAEOCYSTIS UNDER-ICE BLOOMS

2.52.5

4 2.02 4 1.51.5 /Si(OH) 3 /Si(OH) 1.0

3 1 NO 0.5 NO 0.5

0.00

15 15 4 4 1010 /PO /PO 3 3 NO 5

NO 5

Phaeocystis 0

CFL N-ICE SubIce CASES CFL GE SIC GE SIC ICE Diatoms Icescape 2015 2016 - N SUBICE CASES 2016 GE SIC15GE SIC16GE Amundsen ICESCAPE ExpeditionGE Amundsen Ardyna et al. (In prep.) DIATOM VERSUS PHAEOCYSTIS UNDER-ICE BLOOMS Silicate limitation

2.52.5

4 2.02 4 1.51.5 /Si(OH) 3 /Si(OH) 1.0

3 1 NO 0.5 NO 0.5

0.00

15 15 4 4 1010 /PO /PO 3 3 NO 5

NO 5

Phaeocystis 0

CFL N-ICE SubIce CASES CFL GE SIC GE SIC ICE Diatoms Icescape 2015 2016 - N SUBICE CASES 2016 GE SIC15GE SIC16GE Amundsen ICESCAPE ExpeditionGE Amundsen Ardyna et al. (In prep.) DIATOM VERSUS PHAEOCYSTIS UNDER-ICE BLOOMS Silicate limitation

2.52.5

4 2.02 4 1.51.5 /Si(OH) 3 /Si(OH) 1.0 3 1 Other hypotheses still need to be checked: NO 0.5 NO 0.5

0.00 (i) Light-regime control.

15 15 (ii) Water temperature (iii) Top-down control 4 4 1010 (iv) Other limiting nutrients (Vitamin b-12…) /PO /PO 3 3 NO 5

NO 5

Phaeocystis 0

CFL N-ICE SubIce CASES CFL GE SIC GE SIC ICE Diatoms Icescape 2015 2016 - N SUBICE CASES 2016 GE SIC15GE SIC16GE Amundsen ICESCAPE ExpeditionGE Amundsen Ardyna et al. (In prep.) IMPLICATIONS FOR ARCTIC MARINE ECOSYSTEMS ?

Darnis et al. (2012) ! IMPLICATIONS FOR ARCTIC MARINE ECOSYSTEMS ?

Composition

Timing Magnitude

- Carbon transfer to the food web? - Pelagic-benthic coupling

Darnis et al. (2012) ! FUTURE PERSPECTIVES

How are the changing sea-ice dynamics modifying under-ice biogeochemistry and carbon cycle? FUTURE PERSPECTIVES

How are the changing sea-ice dynamics modifying under-ice biogeochemistry and carbon cycle?

How are pulses in biological activity in late and early season inter- connected, and how might marine ecosystems react during in polar night? FUTURE PERSPECTIVES

How are the changing sea-ice dynamics modifying under-ice biogeochemistry and carbon cycle?

How are pulses in biological activity in late and early season inter- connected, and how might marine ecosystems react during in polar night?

The polar night and under-ice environments need more attention!!! Questions???

Acknowledgments: - The Arrigo lab - Takuvik/Green Edge team (Marcel Babin) - LOV team (Hervé Claustre)

C.J. Mundy, Michel Gosselin, Marcel Nicolaus, Philipp Assmy