Biogeochemical processes in Amazon shelf waters: chemical distributions and uptake rates of silicon, carbon and nitrogen

1996 ◽  
Vol 16 (5-6) ◽  
pp. 617-643 ◽  
Author(s):  
D.J. DeMaster ◽  
W.O. Smith ◽  
D.M. Nelson ◽  
J.Y. Aller
Keyword(s):  
Biogeochemical Processes ◽  
Carbon And Nitrogen ◽  
Silicon Carbon ◽  
Uptake Rates ◽  
Amazon Shelf

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

2017 ◽  
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.

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

2018 ◽  
Author(s):  
Bhavya P. Sadanandan ◽  
Jang Han Lee ◽  
Ho Won Lee ◽  
Jae Joong Kaang ◽  
Jae Hyung Lee ◽  
...  
Keyword(s):  
Sea Ice ◽  
Nitrogen Uptake ◽  
N Uptake ◽  
Total Carbon ◽  
The Arctic ◽  
Carbon And Nitrogen ◽  
Uptake Rates ◽  
Wide Range ◽  
Small Phytoplankton

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.

scholarly journals Hidden biosphere in an oxygen-deficient Atlantic open-ocean eddy: future implications of ocean deoxygenation on primary production in the eastern tropical North Atlantic

2015 ◽  
Vol 12 (24) ◽  
pp. 7467-7482 ◽  
Author(s):  
C. R. Löscher ◽  
M. A. Fischer ◽  
S. C. Neulinger ◽  
B. Fiedler ◽  
M. Philippi ◽  
...  
Keyword(s):  
Microbial Community ◽  
Primary Production ◽  
Mixed Layer ◽  
North Atlantic ◽  
Primary Productivity ◽  
Open Ocean ◽  
Carbon Uptake ◽  
Biogeochemical Processes ◽  
Tropical North Atlantic ◽  
Uptake Rates

Abstract. The eastern tropical North Atlantic (ETNA) is characterized by a highly productive coastal upwelling system and a moderate oxygen minimum zone with lowest open-ocean oxygen (O2) concentrations of approximately 40 μmol kg−1. The recent discovery of re-occurring mesoscale eddies with close to anoxic O2 concentrations (< 1 μmol kg−1) located just below the mixed layer has challenged our understanding of O2 distribution and biogeochemical processes in this area. Here, we present the first microbial community study from a deoxygenated anticyclonic modewater eddy in the open waters of the ETNA. In the eddy, we observed significantly lower bacterial diversity compared to surrounding waters, along with a significant community shift. We detected enhanced primary productivity in the surface layer of the eddy indicated by elevated chlorophyll concentrations and carbon uptake rates of up to three times as high as in surrounding waters. Carbon uptake rates below the euphotic zone correlated to the presence of a specific high-light ecotype of Prochlorococcus, which is usually underrepresented in the ETNA. Our data indicate that high primary production in the eddy fuels export production and supports enhanced respiration in a specific microbial community at shallow depths, below the mixed-layer base. The transcription of the key functional marker gene for dentrification, nirS, further indicated a potential for nitrogen loss processes in O2-depleted core waters of the eddy. Dentrification is usually absent from the open ETNA waters. In light of future projected ocean deoxygenation, our results show that even distinct events of anoxia have the potential to alter microbial community structure with critical impacts on primary productivity and biogeochemical processes of oceanic water bodies.

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

2018 ◽  
Vol 15 (18) ◽  
pp. 5503-5517 ◽  
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.

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

2017 ◽  
Vol 14 (15) ◽  
pp. 3705-3713 ◽  
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.

Effect of salinity on silicon, carbon, and nitrogen during decomposition of Spartina alterniflora litter

2017 ◽  
Vol 37 (1) ◽  
Author(s):  
侯贯云 HOU Guanyun ◽  
翟水晶 ZHAI Shuijing ◽  
高会 GAO Hui ◽  
乐晓青 LE Xiaoqing
Keyword(s):  
Spartina Alterniflora ◽  
Carbon And Nitrogen ◽  
Silicon Carbon

scholarly journals Multiple carbon incorporation strategies support microbial survival in cold subseafloor crustal fluids

2021 ◽  
Vol 7 (18) ◽  
pp. eabg0153
Author(s):  
Elizabeth Trembath-Reichert ◽  
Sunita R. Shah Walter ◽  
Marc Alec Fontánez Ortiz ◽  
Patrick D. Carter ◽  
Peter R. Girguis ◽  
...  
Keyword(s):  
Inorganic Carbon ◽  
Biogeochemical Processes ◽  
Carbon And Nitrogen ◽  
Microbial Survival ◽  
Wide Range ◽  
Subsurface Sediments ◽  
Mid Atlantic Ridge ◽  
Potential Strategy ◽  
Globally Distributed ◽  
Quantitative Assessments

Biogeochemical processes occurring in fluids that permeate oceanic crust make measurable contributions to the marine carbon cycle, but quantitative assessments of microbial impacts on this vast, subsurface carbon pool are lacking. We provide bulk and single-cell estimates of microbial biomass production from carbon and nitrogen substrates in cool, oxic basement fluids from the western flank of the Mid-Atlantic Ridge. The wide range in carbon and nitrogen incorporation rates indicates a microbial community well poised for dynamic conditions, potentially anabolizing carbon and nitrogen at rates ranging from those observed in subsurface sediments to those found in on-axis hydrothermal vent environments. Bicarbonate incorporation rates were highest where fluids are most isolated from recharging bottom seawater, suggesting that anabolism of inorganic carbon may be a potential strategy for supplementing the ancient and recalcitrant dissolved organic carbon that is prevalent in the globally distributed subseafloor crustal environment.

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

2016 ◽  
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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