A review on the manuscript, "First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas."

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 μm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labelling experiments for the first time as part of the NABOS (Nansen and Amundsen Basins Observational System) program during August 21 to September 22, 2013. The depth integrated C, NO3−, and NH4+ uptake rates by small phytoplankton showed a wide range from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3−, and NH4+ was varied from 24 to 89 %, 32 to 89 %, and 28 to 89 %, respectively. The turnover times for NO3− and NH4+ by small phytoplankton during the present study point towards the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3−. Relatively, higher C and N uptake rates by small phytoplankton obtained during the present study at locations with less sea ice concentrations points towards the possibility of small phytoplankton thrive under sea ice retreat under warming conditions. The high contributions of small phytoplankton towards the total carbon and nitrogen uptake rates suggest capability of small size autotrophs to withstand in the adverse hydrographic conditions introduced by climate change.

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First in situ estimations of small phytoplankton carbon and nitrogen uptake rates in the Kara, Laptev, and East Siberian seas

Biogeosciences ◽

10.5194/bg-15-5503-2018 ◽

2018 ◽

Vol 15 (18) ◽

pp. 5503-5517 ◽

Cited By ~ 6

Author(s):

P. Sadanandan Bhavya ◽

Jang Han Lee ◽

Ho Won Lee ◽

Jae Joong Kang ◽

Jae Hyung Lee ◽

...

Keyword(s):

Sea Ice ◽

Nitrogen Uptake ◽

Isotope Labeling ◽

N Uptake ◽

The Arctic ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Small Phytoplankton ◽

C And N

Abstract. Carbon and nitrogen uptake rates by small phytoplankton (0.7–5 µm) in the Kara, Laptev, and East Siberian seas in the Arctic Ocean were quantified using in situ isotope labeling experiments; this research, which was novel and part of the NABOS (Nansen and Amundsen Basins Observational System) program, took place from 21 August to 22 September 2013. The depth-integrated carbon (C), nitrate (NO3-), and ammonium (NH4+) uptake rates by small phytoplankton ranged from 0.54 to 15.96 mg C m−2 h−1, 0.05 to 1.02 mg C m−2 h−1, and 0.11 to 3.73 mg N m−2 h−1, respectively. The contributions of small phytoplankton towards the total C, NO3-, and NH4+ varied from 25 % to 89 %, 31 % to 89 %, and 28 % to 91 %, respectively. The turnover times for NO3- and NH4+ by small phytoplankton found in the present study indicate the longer residence times (years) of the nutrients in the deeper waters, particularly for NO3-. Additionally, the relatively higher C and N uptake rates by small phytoplankton obtained in the present study from locations with less sea ice concentration indicate the possibility that small phytoplankton thrive under the retreat of sea ice as a result of warming conditions. The high contributions of small phytoplankton to the total C and N uptake rates suggest the capability of small autotrophs to withstand the adverse hydrographic conditions introduced by climate change.

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Small phytoplankton contribution to the standing stocks and the total primary production in the Amundsen Sea

Biogeosciences ◽

10.5194/bg-14-3705-2017 ◽

2017 ◽

Vol 14 (15) ◽

pp. 3705-3713 ◽

Cited By ~ 8

Author(s):

Sang H. Lee ◽

Bo Kyung Kim ◽

Yu Jeong Lim ◽

HuiTae Joo ◽

Jae Joong Kang ◽

...

Keyword(s):

Primary Production ◽

Chlorophyll A ◽

Nitrogen Uptake ◽

Total Carbon ◽

Phytoplankton Production ◽

Carbon Uptake ◽

Amundsen Sea ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Small Phytoplankton

Abstract. Small phytoplankton are anticipated to be more important in a recently warming and freshening ocean condition. However, little information on the contribution of small phytoplankton to overall phytoplankton production is currently available in the Amundsen Sea. To determine the contributions of small phytoplankton to total biomass and primary production, carbon and nitrogen uptake rates of total and small phytoplankton were obtained from 12 productivity stations in the Amundsen Sea. The daily carbon uptake rates of total phytoplankton averaged in this study were 0.42 g C m−2 d−1 (SD  =  ± 0.30 g C m−2 d−1) and 0.84 g C m−2 d−1 (SD  =  ± 0.18 g C m−2 d−1) for non-polynya and polynya regions, respectively, whereas the daily total nitrogen (nitrate and ammonium) uptake rates were 0.12 g N m−2 d−1 (SD  =  ± 0.09 g N m−2 d−1) and 0.21 g N m−2 d−1 (SD  =  ± 0.11 g N m−2 d−1), respectively, for non-polynya and polynya regions, all of which were within the ranges reported previously. Small phytoplankton contributed 26.9 and 27.7 % to the total carbon and nitrogen uptake rates of phytoplankton in this study, respectively, which were relatively higher than the chlorophyll a contribution (19.4 %) of small phytoplankton. For a comparison of different regions, the contributions for chlorophyll a concentration and primary production of small phytoplankton averaged from all the non-polynya stations were 42.4 and 50.8 %, which were significantly higher than those (7.9 and 14.9 %, respectively) in the polynya region. A strong negative correlation (r2 = 0. 790, p<0. 05) was found between the contributions of small phytoplankton and the total daily primary production of phytoplankton in this study. This finding implies that daily primary production decreases as small phytoplankton contribution increases, which is mainly due to the lower carbon uptake rate of small phytoplankton than large phytoplankton.

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In-situ Measured Carbon and Nitrogen Uptake Rates of Melt Pond Algae in the Western Arctic Ocean, 2014

Ocean Science Journal ◽

10.1007/s12601-018-0002-6 ◽

2018 ◽

Vol 53 (1) ◽

pp. 107-117 ◽

Cited By ~ 1

Author(s):

Ho Jung Song ◽

Kwanwoo Kim ◽

Jae Hyung Lee ◽

So Hyun Ahn ◽

Houng-Min Joo ◽

...

Keyword(s):

Arctic Ocean ◽

Nitrogen Uptake ◽

Western Arctic Ocean ◽

Carbon And Nitrogen ◽

Melt Pond ◽

Uptake Rates ◽

Western Arctic

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Small phytoplankton contribution to the total primary production in the Amundsen Sea

10.5194/bg-2016-453 ◽

2016 ◽

Author(s):

Sang H. Lee ◽

Bo Kyung Kim ◽

Yu Jeong Lim ◽

HuiTae Joo ◽

Dabin Lee ◽

...

Keyword(s):

Primary Production ◽

Chlorophyll A ◽

Nitrogen Uptake ◽

Total Carbon ◽

Ammonium Uptake ◽

Phytoplankton Production ◽

Amundsen Sea ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Small Phytoplankton

Abstract. Small-sized phytoplankton is anticipated to be more important for phytoplankton community in a recent changing ocean condition. However, little information on the contribution of small-sized phytoplankton to overall phytoplankton production is currently available in the Amundsen Sea. To determine the contributions of small-sized phytoplankton to total biomass and primary production, carbon and nitrogen uptake rates of total and small-sized phytoplankton were obtained from 12 productivity stations in the Amundsen Sea. The daily carbon uptake rates of total phytoplankton averaged in this study were 0.42 g C m−2 d−1 (S.D. = ±0.30 g C m−2 d−1) and 0.84 g C m−2 d−1 (S.D. = ±0.18 g C m−2 d−1) whereas the daily total nitrogen (nitrate and ammonium) uptake rates were 0.12 g N m−2 d−1 (S.D. = ±0.09 g N m−2 d−1) and 0.21 g N m−2 d−1 (S.D. = ±0.11 g N m−2 d−1), respectively for non-polynya and polynya regions, which were within the ranges reported previously. Small phytoplankton contributed 26.9 % and 27.7 % to the total carbon and nitrogen uptake rates of phytoplankton in this study, respectively, which were relatively higher than the chlorophyll-a contribution (19.4 %) of small phytoplankton. For a comparison of different regions, the contributions for chlorophyll-a concentration and primary production of small phytoplankton averaged from all the non-polynya stations were 42.4 % and 50.8 %, which were significantly higher than those (7.9 % and 14.9 %, respectively) in polynya region. A strong negative correlation (r2 = 0.790, p

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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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Effect of increased temperature on carbon and nitrogen uptake of two intertidal foraminifera (<i>Ammonia tepida</i> and <i>Haynesina germanica</i>)

10.5194/bg-2016-509 ◽

2016 ◽

Cited By ~ 1

Author(s):

Julia Wukovits ◽

Annekatrin J. Enge ◽

Wolfgang Wanek ◽

Margarete Watzka ◽

Petra Heinz

Keyword(s):

Nitrogen Uptake ◽

Food Source ◽

Environmental Changes ◽

Potential Temperature ◽

Carbon Uptake ◽

Nutrient Fluxes ◽

Carbon And Nitrogen ◽

Foraminiferal Species ◽

Freeze Dried ◽

Uptake Rates

Abstract. Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but intertidal communities are expected to undergo future changes. Environmental changes can exceed the tolerance limits of intertidal species causing a shift in species composition which might result in altered nutrient fluxes. Factors limiting the abundance of specific foraminiferal species can be temperature related stress tolerance or food source processing efficiency. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus ingestion. The specimens were fed with 13C and 15N labelled freeze dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20 °C, 25 °C, and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of two weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on carbon uptake of H. germanica than on A. tepida. A distinct increase in levels of phytodetrital derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods, if the main food source consists of chlorophyte phytodetritus. These conditions are likely to impact nutrient fluxes in A. tepida/H. germanica associations.

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Recent carbon and nitrogen uptake rates of phytoplankton in Bering Strait and the Chukchi Sea

Continental Shelf Research ◽

10.1016/j.csr.2007.05.009 ◽

2007 ◽

Vol 27 (17) ◽

pp. 2231-2249 ◽

Cited By ~ 84

Author(s):

Sang H. Lee ◽

Terry E. Whitledge ◽

Sung-Ho Kang

Keyword(s):

Nitrogen Uptake ◽

Chukchi Sea ◽

Bering Strait ◽

Carbon And Nitrogen ◽

Uptake Rates

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In Situ Rates of Carbon and Nitrogen Uptake by Phytoplankton and the Contribution of Picophytoplankton in Kongsfjorden, Svalbard

Water ◽

10.3390/w12102903 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2903

Author(s):

Bo Kyung Kim ◽

Hyoung Min Joo ◽

Jinyoung Jung ◽

Boyeon Lee ◽

Sun-Yong Ha

Keyword(s):

Nitrogen Uptake ◽

Uptake Rate ◽

Carbon Fixation ◽

Total Carbon ◽

Phytoplankton Production ◽

Carbon Uptake ◽

Chl A ◽

Carbon And Nitrogen ◽

Uptake Rates ◽

Isotope Technique

Rapid climate warming and the associated melting of glaciers in high-latitude open fjord systems can have a significant impact on biogeochemical cycles. In this study, the uptake rates of carbon and nitrogen (nitrate and ammonium) of total phytoplankton and picophytoplankton (<2 μm) were measured in Kongsfjorden in early May 2017 using the dual stable isotope technique. The daily uptake rates of total carbon and nitrogen ranged from 0.3 to 1.1 g C m−2 day−1, with a mean of 0.7 ± 0.3 g C m−2 day−1, and 0.13 to 0.17 g N m−2 day−1, with a mean of 0.16 ± 0.02 g N m−2 day−1. Microphytoplankton (20–200 μm) accounted for 68.1% of the total chlorophyll a (chl-a) concentration, while picophytoplankton (<2 μm) accounted for 19.6% of the total chl-a, with a high contribution to the carbon uptake rate (42.9%) due to its higher particulate organic carbon-to-chl-a ratio. The contributions of picophytoplankton to the total nitrogen uptake rates were 47.1 ± 10.6% for nitrate and 74.0 ± 16.7% for ammonium. Our results indicated that picophytoplankton preferred regenerated nitrogen, such as ammonium, for growth and pointed to the importance of the role played by picophytoplankton in the local carbon uptake rate during the early springtime in 2017. Although the phytoplankton community, in terms of biovolume, in all samples was dominated by diatoms and Phaeocystis sp., a higher proportion of nano- and picophytoplankton chl-a (mean ± SD = 71.3 ± 16.4%) was observed in the relatively cold and turbid surface water in the inner fjord. Phytoplankton production (carbon uptake) decreased towards the inner fjord, while nitrogen uptake increased. The contrast in carbon and nitrogen uptake is likely caused by the gradient in glacial meltwater which affects both the light regime and nutrient availability. Therefore, global warming-enhanced glacier melting might support lower primary production (carbon fixation) with higher degrees of regeneration processes in fjord systems.

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