Carbon Biogeochemistry of the Western Arctic: Primary Production, Carbon Export and the Controls on Ocean Acidification

Abstract. Anthropogenic carbon dioxide (CO2) emissions are reducing the pH in the world's oceans. The plankton community is a key component driving biogeochemical fluxes, and the effect of increased CO2 on plankton is critical for understanding the ramifications of ocean acidification on global carbon fluxes. We determined the plankton community composition and measured primary production, respiration rates and carbon export (defined here as carbon sinking out of a shallow, coastal area) during an ocean acidification experiment. Mesocosms (~ 55 m3) were set up in the Baltic Sea with a gradient of CO2 levels initially ranging from ambient (~ 240 μatm), used as control, to high CO2 (up to ~ 1330 μatm). The phytoplankton community was dominated by dinoflagellates, diatoms, cyanobacteria and chlorophytes, and the zooplankton community by protozoans, heterotrophic dinoflagellates and cladocerans. The plankton community composition was relatively homogenous between treatments. Community respiration rates were lower at high CO2 levels. The carbon-normalized respiration was approximately 40 % lower in the high CO2 environment compared with the controls during the latter phase of the experiment. We did not, however, detect any effect of increased CO2 on primary production. This could be due to measurement uncertainty, as the measured total particular carbon (TPC) and combined results presented in this special issue suggest that the reduced respiration rate translated into higher net carbon fixation. The percent carbon derived from microscopy counts (both phyto- and zooplankton), of the measured total particular carbon (TPC) decreased from ~ 26 % at t0 to ~ 8 % at t31, probably driven by a shift towards smaller plankton (< 4 μm) not enumerated by microscopy. Our results suggest that reduced respiration lead to increased net carbon fixation at high CO2. However, the increased primary production did not translate into increased carbon export, and did consequently not work as a negative feedback mechanism for increasing atmospheric CO2 concentration.

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Ocean acidification decreases plankton respiration: evidence from a mesocosm experiment

Biogeosciences ◽

10.5194/bg-13-4707-2016 ◽

2016 ◽

Vol 13 (16) ◽

pp. 4707-4719 ◽

Cited By ~ 12

Author(s):

Kristian Spilling ◽

Allanah J. Paul ◽

Niklas Virkkala ◽

Tom Hastings ◽

Silke Lischka ◽

...

Keyword(s):

Primary Production ◽

Ocean Acidification ◽

Community Composition ◽

Carbon Fixation ◽

Plankton Community ◽

Community Respiration ◽

Carbon Export ◽

High Co2 ◽

Respiration Rates ◽

Co2 Levels

Abstract. Anthropogenic carbon dioxide (CO2) emissions are reducing the pH in the world's oceans. The plankton community is a key component driving biogeochemical fluxes, and the effect of increased CO2 on plankton is critical for understanding the ramifications of ocean acidification on global carbon fluxes. We determined the plankton community composition and measured primary production, respiration rates and carbon export (defined here as carbon sinking out of a shallow, coastal area) during an ocean acidification experiment. Mesocosms ( ∼  55 m3) were set up in the Baltic Sea with a gradient of CO2 levels initially ranging from ambient ( ∼  240 µatm), used as control, to high CO2 (up to ∼  1330 µatm). The phytoplankton community was dominated by dinoflagellates, diatoms, cyanobacteria and chlorophytes, and the zooplankton community by protozoans, heterotrophic dinoflagellates and cladocerans. The plankton community composition was relatively homogenous between treatments. Community respiration rates were lower at high CO2 levels. The carbon-normalized respiration was approximately 40 % lower in the high-CO2 environment compared with the controls during the latter phase of the experiment. We did not, however, detect any effect of increased CO2 on primary production. This could be due to measurement uncertainty, as the measured total particular carbon (TPC) and combined results presented in this special issue suggest that the reduced respiration rate translated into higher net carbon fixation. The percent carbon derived from microscopy counts (both phyto- and zooplankton), of the measured total particular carbon (TPC), decreased from ∼  26 % at t0 to ∼  8 % at t31, probably driven by a shift towards smaller plankton (< 4 µm) not enumerated by microscopy. Our results suggest that reduced respiration leads to increased net carbon fixation at high CO2. However, the increased primary production did not translate into increased carbon export, and consequently did not work as a negative feedback mechanism for increasing atmospheric CO2 concentration.

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Primary production and carbon export rates across the subpolar N. Atlantic Ocean basin based on triple oxygen isotope and dissolved O2and Ar gas measurements

Global Biogeochemical Cycles ◽

10.1029/2010gb004003 ◽

2012 ◽

Vol 26 (2) ◽

pp. n/a-n/a ◽

Cited By ~ 31

Author(s):

P. Quay ◽

J. Stutsman ◽

T. Steinhoff

Keyword(s):

Atlantic Ocean ◽

Primary Production ◽

Oxygen Isotope ◽

Ocean Basin ◽

Carbon Export ◽

Gas Measurements ◽

Ar Gas

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Field-obtained carbon and nitrogen uptake rates of phytoplankton in the Laptev and East Siberian seas

10.5194/bg-2017-234 ◽

2017 ◽

Cited By ~ 1

Author(s):

Sang Heon Lee ◽

Jang Han Lee ◽

Howon Lee ◽

Jae Joong Kang ◽

Jae Hyung Lee ◽

...

Keyword(s):

Primary Production ◽

Arctic Ocean ◽

Nitrogen Uptake ◽

The Arctic ◽

Chl A ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Order Of Magnitude ◽

Western Arctic ◽

System Program

Abstract. The Laptev and East Siberian seas are the least biologically studied region in the Arctic Ocean, although they are highly dynamic in terms of active processing of organic matter impacting the transport to the deep Arctic Ocean. Field-measured carbon and nitrogen uptake rates of phytoplankton were conducted in the Laptev and East Siberian seas as part of the NABOS (Nansen and Amundsen Basins Observational System) program. Major inorganic nutrients were mostly depleted at 100–50 % light depths but were not depleted within the euphotic depths in the Laptev and East Siberian seas. The water column-integrated chl-a concentration in this study was significantly higher than that in the western Arctic Ocean (t-test, p > 0.01). Unexpectedly, the daily carbon and nitrogen uptake rates in this study (average ± S.D. = 110.3 ± 88.3 mg C m−2 d−1 and 37.0 ± 25.8 mg N m−2 d−1, respectively) are within previously reported ranges. Surprisingly, the annual primary production (13.2 g C m−2) measured in the field during the vegetative season is approximately one order of magnitude lower than the primary production reported from a satellite–based estimation. Further validation using field-measured observations is necessary for a better projection of the ecosystem in the Laptev and East Siberian seas responding to ongoing climate change.

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Evidence for benthic-pelagic food web coupling and carbon export from California margin bamboo coral archives

Biogeosciences Discussions ◽

10.5194/bgd-11-2595-2014 ◽

2014 ◽

Vol 11 (2) ◽

pp. 2595-2621 ◽

Cited By ~ 1

Author(s):

T. M. Hill ◽

C. R. Myrvold ◽

H. J. Spero ◽

T. P. Guilderson

Keyword(s):

Primary Production ◽

Deep Sea ◽

Benthic Communities ◽

California Current ◽

Strong Relationship ◽

Nitrogen Isotope ◽

Carbon Export ◽

Carbon And Nitrogen ◽

Pelagic Food Webs

Abstract. Deep-sea bamboo corals (order Gorgonacea, family Isididae) are known to record changes in water mass chemistry over decades to centuries. These corals are composed of a two-part skeleton of calcite internodes segmented by gorgonin organic nodes. We examine the spatial variability of bamboo coral organic node 13C/12C and 15N/14N from thirteen bamboo coral specimens sampled along the California margin (37–32° N; 792 to 2136 m depth). Radiocarbon analyses of the organic nodes show the presence of the anthropogenic bomb spike, indicating the corals utilize a surface-derived food source (pre-bomb D14C values of ∼ −100‰, post-bomb values to 82‰). Carbon and nitrogen isotope data from the organic nodes (13C = −15.9‰ to −19.2‰ 15N = 13.8‰ to 19.4‰) suggest selective feeding on surface-derived organic matter or zooplankton. A strong relationship between coral 15N and habitat depth indicate a potential archive of changing carbon export, with decreased 15N values reflecting reduced microbial degradation (increased carbon flux) at shallower depths. Using four multi-centennial length coral records, we interpret long-term 15N stability in the California Current. Organic node 13C values record differences in carbon isotope fractionation dictated by nearshore vs. offshore primary production. These findings imply strong coupling between primary production, pelagic food webs, and deep-sea benthic communities.

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Size-fractionated primary production and nitrogen uptake during a North Atlantic phytoplankton bloom: implications for carbon export estimates

Deep Sea Research Part I Oceanographic Research Papers ◽

10.1016/s0967-0637(00)00066-2 ◽

2001 ◽

Vol 48 (3) ◽

pp. 689-720 ◽

Cited By ~ 56

Author(s):

S.J Bury ◽

P.W Boyd ◽

T Preston ◽

G Savidge ◽

N.J.P Owens

Keyword(s):

Primary Production ◽

North Atlantic ◽

Nitrogen Uptake ◽

Phytoplankton Bloom ◽

Carbon Export

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Changes in phytoplankton concentration now drive increased Arctic Ocean primary production

Science ◽

10.1126/science.aay8380 ◽

2020 ◽

Vol 369 (6500) ◽

pp. 198-202 ◽

Cited By ~ 18

Author(s):

K. M. Lewis ◽

G. L. van Dijken ◽

K. R. Arrigo

Keyword(s):

Sea Ice ◽

Primary Production ◽

Arctic Ocean ◽

Open Water ◽

Water Area ◽

The Arctic ◽

Carbon Export ◽

Phytoplankton Primary Production ◽

Open Water Area ◽

The Arctic Ocean

Historically, sea ice loss in the Arctic Ocean has promoted increased phytoplankton primary production because of the greater open water area and a longer growing season. However, debate remains about whether primary production will continue to rise should sea ice decline further. Using an ocean color algorithm parameterized for the Arctic Ocean, we show that primary production increased by 57% between 1998 and 2018. Surprisingly, whereas increases were due to widespread sea ice loss during the first decade, the subsequent rise in primary production was driven primarily by increased phytoplankton biomass, which was likely sustained by an influx of new nutrients. This suggests a future Arctic Ocean that can support higher trophic-level production and additional carbon export.

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