scholarly journals Summertime Chlorophyll a and Particulate Organic Carbon Standing Stocks in Surface Waters of the Fram Strait and the Arctic Ocean (1991–2015)

2020 ◽  
Vol 7 ◽  
Author(s):  
Eva-Maria Nöthig ◽  
Simon Ramondenc ◽  
Antonie Haas ◽  
Laura Hehemann ◽  
Andreas Walter ◽  
...  
2019 ◽  
Vol 59 (4) ◽  
pp. 544-552
Author(s):  
A. A. Vetrov ◽  
E. A. Romankevich

Particulate organic carbon (POC) is one of main component of carbon cycle in the Ocean. In this study an attempt to construct a picture of the distribution and fluxes of POC in the Arctic Ocean adjusting for interchange with the Pacific and Atlantic Oceans has been made. The specificity of this construction is associated with an irregular distribution of POC measurements and complicated structure and hydrodynamics of the waters masses. To overcome these difficulties, Multiple Linear Regression technic (MLR) was performed to test the significant relation between POC, temperature, salinity, as well depth, horizon, latitude and offshore distance. The mapping of POC distribution and its fluxes was carrying out at 38 horizons from 5 to 4150 m (resolution 1°×1°). Data on temperature, salinity, meridional and zonal components of current velocities were obtained from ORA S4 database (Integrated Climate Data Center, http://icdc.cen.uni-hamburg.de/las). The import-export of POC between the Arctic, Atlantic and Pacific Oceans as well as between Arctic Seas was precomputed by summer fluxes. The import of POC in the Arctic Ocean is estimated to be 38±8Tg Cyr-1, and the export is -9.5±4.4Tg Cyr-1.


2021 ◽  
Author(s):  
Daria Polosukhina ◽  
Anatoly Prokushkin ◽  
Axel Steinhof

<p>There is the significant progress in recent decades in the quantification of terrigenous carbon release to the rivers of the Arctic Ocean basin and characterization of its chemical properties, origin and age (e.g. Amon et al., 2012, Holmes et al., 2012). As warming accelerates the thawing permafrost may potentially increase the release the ancient carbon (Wild et al., 2019, Estop-Aragonés et al., 2020). However, more detailed analysis is still needed particularly in regard of the age of carbon exported from the diverse landscapes of large Arctic rivers and its transformation during the transport to the Arctic ocean.</p><p>In this study we analyzed D14C in dissolved organic carbon (DOC) and particulate organic carbon (POC) of the Yenisei River main channel and its major tributaries between 56oN and 68oN at freshet, summer and fall seasons. D14C was measured in Max Planck Institute for Biogeochemistry (Germany) by the accelerator mass spectrometry (AMS) system based on a 3MV Tandetron accelerator as described earlier (Steinhof et al., 2017).</p><p> The oldest DOC in the Yenisei main stem was detected right after the Krasnoyarsk dam (56oN) and varied during a year without clear seasonal pattern in the range of the fraction of modern C (fMC) from 0.868 to 1.028. At freshet the fMC increased down stream up to 1.12 at 60oN and then remained relatively stable between 61o and 67.4oN (1.097±0.014). The major tributaries released DOC with fMC ranging from 1.0869 (Angara, 58oN) to 1.1046 (Kurejka (66.5oN), demonstrating more modern C with latitude. During the summer-fall season the Yenisei main channel and main Eastern tributaries contained older DOC (fMC = 0.968-1.054 and 0.949-1.045, respectively).</p><p>The POC of the Yenisei River was sufficiently older (fMC = 0.83-0.92) than DOC at all seasons and showed similar latitudinal pattern, i.e. the youngest POC was detected near 60-61oN (fMC > 0.90). The D14C-POC values in analyzed tributaries were increasing with latitude at freshet (R2 = 0.53) and summer lowflow (R2 = 0.33), except the largest Eastern tributaries, demonstrating the slight opposite pattern. On the other hand, increasingly more ancient POC was releasing by permafrost-dominated Eastern tributaries with increasing basin size. In opposite, D14C-POC of Western tributaries showed increased input of more recently fixed carbon. Our findings provided new data on the formation of terrigenic carbon fluxes to the Arctic Ocean from one of the largest river basins in the Arctic. This study was supported by RFBR grants #18-05-60203-Arktika. The radiocarbon analyses were kindly supported by Max-Plank Institute for biogeochemistry (ZOTTO project).</p>


2021 ◽  
Vol 8 ◽  
Author(s):  
Griselda Anglada-Ortiz ◽  
Katarzyna Zamelczyk ◽  
Julie Meilland ◽  
Patrizia Ziveri ◽  
Melissa Chierici ◽  
...  

Planktic foraminifera and shelled pteropods are some of the major producers of calcium carbonate (CaCO3) in the ocean. Their calcitic (foraminifera) and aragonitic (pteropods) shells are particularly sensitive to changes in the carbonate chemistry and play an important role for the inorganic and organic carbon pump of the ocean. Here, we have studied the abundance distribution of planktic foraminifera and pteropods (individuals m–3) and their contribution to the inorganic and organic carbon standing stocks (μg m–3) and export production (mg m–2 day–1) along a longitudinal transect north of Svalbard at 81° N, 22–32° E, in the Arctic Ocean. This transect, sampled in September 2018 consists of seven stations covering different oceanographic regimes, from the shelf to the slope and into the deep Nansen Basin. The sea surface temperature ranged between 1 and 5°C in the upper 300 m. Conditions were supersaturated with respect to CaCO3 (Ω > 1 for both calcite and aragonite). The abundance of planktic foraminifera ranged from 2.3 to 52.6 ind m–3 and pteropods from 0.1 to 21.3 ind m–3. The planktic foraminiferal population was composed mainly of the polar species Neogloboquadrina pachyderma (55.9%) and the subpolar species Turborotalita quinqueloba (21.7%), Neogloboquadrina incompta (13.5%) and Globigerina bulloides (5.2%). The pteropod population was dominated by the polar species Limacina helicina (99.6%). The rather high abundance of subpolar foraminiferal species is likely connected to the West Spitsbergen Current bringing warm Atlantic water to the study area. Pteropods dominated at the surface and subsurface. Below 100 m water depth, foraminifera predominated. Pteropods contribute 66–96% to the inorganic carbon standing stocks compared to 4–34% by the planktic foraminifera. The inorganic export production of planktic foraminifera and pteropods together exceeds their organic contribution by a factor of 3. The overall predominance of pteropods over foraminifera in this high Arctic region during the sampling period suggest that inorganic standing stocks and export production of biogenic carbonate would be reduced under the effects of ocean acidification.


2013 ◽  
Vol 10 (3) ◽  
pp. 1451-1469 ◽  
Author(s):  
R. Vaquer-Sunyer ◽  
C. M. Duarte ◽  
J. Holding ◽  
A. Regaudie-de-Gioux ◽  
L. S. García-Corral ◽  
...  

Abstract. The metabolism of the Arctic Ocean is marked by extremely pronounced seasonality and spatial heterogeneity associated with light conditions, ice cover, water masses and nutrient availability. Here we report the marine planktonic metabolic rates (net community production, gross primary production and community respiration) along three different seasons of the year, for a total of eight cruises along the western sector of the European Arctic (Fram Strait – Svalbard region) in the Arctic Ocean margin: one at the end of 2006 (fall/winter), two in 2007 (early spring and summer), two in 2008 (early spring and summer), one in 2009 (late spring–early summer), one in 2010 (spring) and one in 2011 (spring). The results show that the metabolism of the western sector of the European Arctic varies throughout the year, depending mostly on the stage of bloom and water temperature. Here we report metabolic rates for the different periods, including the spring bloom, summer and the dark period, increasing considerably the empirical basis of metabolic rates in the Arctic Ocean, and especially in the European Arctic corridor. Additionally, a rough annual metabolic estimate for this area of the Arctic Ocean was calculated, resulting in a net community production of 108 g C m−2 yr−1.


2011 ◽  
Vol 8 (2) ◽  
pp. 2093-2143 ◽  
Author(s):  
I. P. Semiletov ◽  
I. I. Pipko ◽  
N. E. Shakhova ◽  
O. V. Dudarev ◽  
S. P. Pugach ◽  
...  

Abstract. The Lena River integrates biogeochemical signals from its vast drainage basin and its signal reaches far out over the Arctic Ocean. Transformation of riverine organic carbon into mineral carbon, and mineral carbon into the organic form in the Lena River watershed, can be considered a quasi-equilibrated processes. Increasing the Lena discharge causes opposite effects on total organic (TOC) and inorganic (TCO2) carbon: TOC concentration increases, while TCO2 concentration decreases. Significant inter-annual variability in mean values of TCO2, TOC, and their sum (TC) has been found. This variability is determined by changes in land hydrology which cause differences in the Lena River discharge, because a negative correlation may be found between TC in September and mean discharge in August (a time shift of about one month is required for water to travel from Yakutsk to the Laptev Sea). Total carbon entering the sea with the Lena discharge is estimated to be almost 10 Tg C y−1. The annual Lena River discharge of particulate organic carbon (POC) may be equal to 0.38 Tg (moderate to high estimate). If we instead accept Lisytsin's (1994) statement concerning the precipitation of 85–95% of total particulate matter (PM) (and POC) on the marginal "filter", then only about 0.03–0.04 Tg of POC reaches the Laptev Sea from the Lena River. The Lena's POC export would then be two orders of magnitude less than the annual input of eroded terrestrial carbon onto the shelf of the Laptev and East Siberian seas, which is about 4 Tg. The Lena River is characterized by relatively high concentrations of primary greenhouse gases: CO2 and dissolved CH4. During all seasons the river is supersaturated in CO2 compared to the atmosphere: up to 1.5–2 fold in summer, and 4–5 fold in winter. This results in a narrow zone of significant CO2 supersaturation in the adjacent coastal sea. Spots of dissolved CH4 in the Lena delta channels may reach 100 nM, but the CH4 concentration decreases to 5–20 nM towards the sea, which suggests only a minor role of riverborne export of CH4 for the East Siberian Arctic Shelf (ESAS) CH4 budget in coastal waters. Instead, the seabed appears to be the source that provides most of the CH4 to the Arctic Ocean.


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