Stable isotopes in planktonic and benthic foraminifera from Arctic Ocean surface sediments

1988 ◽  
Vol 25 (5) ◽  
pp. 701-709 ◽  
Author(s):  
A. E. Aksu ◽  
G. Vilks
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
Sea Water ◽  
Ocean Surface ◽  
The Arctic ◽  
Size Fractions ◽  
Isotopic Compositions ◽  
Isotopic Analyses ◽  
Stable Isotopic ◽  
Surface Water Salinity

Oxygen and carbon isotopic analyses have been performed on the tests of Planulina wuellerstorfi and three size fractions of sinistral Neogloboquadrina pachyderma recovered from 33 Arctic Ocean surface-sediment samples. Stable isotopic compositions of N. pachyderma are found to be dependent on the test size: larger specimens show considerable enrichment in both δ18O and δ18C. The difference between the isotopic compositions of the 63–125 and 125–250 μm size fractions in N. pachyderma can be explained by biogenic fractionation effects during foraminiferal test growth. Larger (250–500 μm) N. pachyderma displayed accretions of secondary calcite, i.e., the outermost shell contained significant amounts of inorganically precipitated magnesium calcite. Thus, larger foraminifera may not be suited for down-core stable isotopic studies. There is a difference of ~2‰ between δ18O values of surface samples from the eastern and western Arctic Ocean, reflecting large differences between surface-water salinity in these regions. Therefore, oxygen isotopic data may have limited use as a chronostratigraphic tool in down-core studies in the Arctic Ocean, but we can use them to infer past variations in surface-water salinities. Planulina wuellerstorfi also showed depletions of both δ18O and δ18C in its calcite tests relative to calcite precipitated in isotopic equilibrium with ambient sea water; these depletions ranged from −0.8 to −0.9‰ in δ18Oand −1.2 to −0.9‰ in δ18C. This taxon is found to deposit its shell very close to the δ18C of ΣCO2 of bottom waters.

scholarly journals Methane production in aerobic oligotrophic surface water in the central Arctic Ocean

2010 ◽  
Vol 7 (3) ◽  
pp. 1099-1108 ◽  
Author(s):  
E. Damm ◽  
E. Helmke ◽  
S. Thoms ◽  
U. Schauer ◽  
E. Nöthig ◽  
...  
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
Methane Production ◽  
Sea Water ◽  
Ocean Surface ◽  
N:P Ratio ◽  
Biological Processes ◽  
Central Arctic Ocean ◽  
Arctic Sea ◽  
The Common

Abstract. A methane surplus relative to the atmospheric equilibrium is a frequently observed feature of ocean surface water. Despite the common fact that biological processes are responsible for its origin, the formation of methane in aerobic surface water is still poorly understood. We report on methane production in the central Arctic Ocean, which was exclusively detected in Pacific derived water but not nearby in Atlantic derived water. The two water masses are distinguished by their different nitrate to phosphate ratios. We show that methane production occurs if nitrate is depleted but phosphate is available as a P source. Apparently the low N:P ratio enhances the ability of bacteria to compete for phosphate while the phytoplankton metabolite dimethylsulfoniopropionate (DMSP) is utilized as a C source. This was verified by experimentally induced methane production in DMSP spiked Arctic sea water. Accordingly we propose that methylated compounds may serve as precursors for methane and thermodynamic calculations show that methylotrophic methanogenesis can provide energy in aerobic environments.

scholarly journals Methane production in aerobic oligotrophic surface water in the central Arctic Ocean

2009 ◽  
Vol 6 (6) ◽  
pp. 10355-10379 ◽  
Author(s):  
E. Damm ◽  
E. Helmke ◽  
S. Thoms ◽  
U. Schauer ◽  
E. Nöthig ◽  
...  
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
Methane Production ◽  
Sea Water ◽  
Ocean Surface ◽  
N:P Ratio ◽  
Biological Processes ◽  
Central Arctic Ocean ◽  
Arctic Sea ◽  
The Common

Abstract. A methane surplus relative to the atmospheric equilibrium is a frequent feature of ocean surface water. Despite the common fact that biological processes are responsible for its origin, the formation of methane in aerobic surface water is still poorly understood. We report on methane production in the central Arctic Ocean, which was exclusively detected in Pacific derived water but not nearby in Atlantic derived water. Both water masses are distinguished by their different nitrate to phosphate ratios. We show that methane production occurs if nitrate is depleted but phosphate as P source is available. Apparently the low N:P ratio enhances the ability of bacteria to compete for phosphate while the phytoplankton metabolite dimethylsulfoniopropionate (DMSP) is utilized as a C source. This was verified by experimentally induced methane production in DMSP spiked Arctic sea water. Accordingly we propose that methylated compounds may serve as precursors for methane and thermodynamic calculations show that methylothrophic methanogenesis can provide energy in aerobic environments.

Petroleum hydrocarbons in the arctic ocean surface water

1982 ◽  
Vol 13 (6) ◽  
pp. 211-213 ◽  
Author(s):  
Elisabet Fogelqvist ◽  
Sören Lagerkvist ◽  
Peter Lindroth
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
Petroleum Hydrocarbons ◽  
Ocean Surface ◽  
The Arctic ◽  
The Arctic Ocean

scholarly journals Preliminary Screening for Microplastic Concentrations in the Surface Water of the Ob and Tom Rivers in Siberia, Russia

2020 ◽  
Vol 13 (1) ◽  
pp. 80
Author(s):  
Yulia A. Frank ◽  
Egor D. Vorobiev ◽  
Danil S. Vorobiev ◽  
Andrey A. Trifonov ◽  
Dmitry V. Antsiferov ◽  
...  
Keyword(s):  
Surface Water ◽  
Arctic Ocean ◽  
River System ◽  
The Arctic ◽  
Preliminary Screening ◽  
Freshwater Systems ◽  
Ob River ◽  
The Arctic Ocean ◽  
Abundance And Diversity ◽  
Blank Spot

To date, the largest Russian rivers discharging to the Arctic Ocean remain a “blank spot” on the world map of data on the distribution of microplastics in freshwater systems. This study characterizes the abundance and morphology of microplastics in surface water of the Ob River and its large tributary, the Tom River, in western Siberia. The average number of particles for the two rivers ranged from 44.2 to 51.2 items per m3 or from 79.4 to 87.5 μg per m3 in the Tom River and in the Ob River, respectively. Of the recovered microplastics, 93.5% were less than 1 mm in their largest dimension, the largest group (45.5% of total counts) consisted of particles with sizes range 0.30–1.00 mm. Generally, microfragments of irregular shape were the most abundant among the Ob and Tom samples (47.4%) and exceeded microfibers (22.1%), microfilms (20.8%), and microspheres (9.74%) by average counts. Results from this study provide a baseline for understanding the scale of the transport of microplastics by the Ob River system into the Arctic Ocean and add to currently available data on microplastics abundance and diversity in freshwater systems of differing global geographic locations.

scholarly journals An 18S V4 rDNA metabarcoding dataset of protist diversity in the Atlantic inflow to the Arctic Ocean, through the year and down to 1000 m depth

2021 ◽  
Author(s):  
Elianne Egge ◽  
Stephanie Elferink ◽  
Daniel Vaulot ◽  
Uwe John ◽  
Gunnar Bratbak ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
High Throughput Sequencing ◽  
Sea Water ◽  
Size Fraction ◽  
The Arctic ◽  
Reference Database ◽  
Rrna Gene ◽  
Svalbard Archipelago ◽  
The Arctic Ocean ◽  
Epipelagic Zone

AbstractArctic marine protist communities have been understudied due to challenging sampling conditions, in particular during winter and in deep waters. The aim of this study was to improve our knowledge on Arctic protist diversity through the year, both in the epipelagic (< 200 m depth) and mesopelagic zones (200-1000 m depth). Sampling campaigns were performed in 2014, during five different months, to capture the various phases of the Arctic primary production: January (winter), March (pre-bloom), May (spring bloom), August (post-bloom) and November (early winter). The cruises were undertaken west and north of the Svalbard archipelago, where warmer Atlantic waters from the West Spitsbergen Current meets cold Arctic waters from the Arctic Ocean. From each cruise, station, and depth, 50 L of sea water were collected and the plankton was size-fractionated by serial filtration into four size fractions between 0.45-200 µm, representing the picoplankton, nanoplankton and microplankton. In addition vertical net hauls were taken from 50 m depth to the surface at selected stations. From the plankton samples DNA was extracted, the V4 region of the 18S rRNA-gene was amplified by PCR with universal eukaryote primers and the amplicons were sequenced by Illumina high-throughput sequencing. Sequences were clustered into Amplicon Sequence Variants (ASVs), representing protist genotypes, with the dada2 pipeline. Taxonomic classification was made against the curated Protist Ribosomal Reference database (PR2). Altogether 6,536 protist ASVs were obtained (including 54 fungal ASVs). Both ASV richness and taxonomic composition were strongly dependent on size-fraction, season, and depth. ASV richness was generally higher in the smaller fractions, and higher in winter and the mesopelagic samples than in samples from the well-lit epipelagic zone during summer. During spring and summer, the phytoplankton groups diatoms, chlorophytes and haptophytes dominated in the epipelagic zone. Parasitic and heterotrophic groups such as Syndiniales and certain dinoflagel-lates dominated in the mesopelagic zone all year, as well as in the epipelagic zone during the winter. The dataset is available at https://doi.org/10.17882/79823, (Egge et al., 2014).

scholarly journals Stable silicon isotopic compositions of the Lena River and its tributaries: Implications for silicon delivery to the Arctic Ocean

2018 ◽  
Vol 241 ◽  
pp. 120-133 ◽  
Author(s):  
Xiaole Sun ◽  
Carl-Magnus Mörth ◽  
Don Porcelli ◽  
Liselott Kutscher ◽  
Catherine Hirst ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Lena River ◽  
Isotopic Compositions ◽  
The Arctic Ocean

scholarly journals Interannual variability of parameters of the Arctic Ocean surface layer and halocline

2020 ◽  
Vol 66 (4) ◽  
pp. 404-426
Author(s):  
E. A. Cherniavskaia ◽  
L. A. Timokhov ◽  
V. Y. Karpiy ◽  
S. Y. Malinovskiy
Keyword(s):  
Surface Layer ◽  
Arctic Ocean ◽  
Interannual Variability ◽  
Ocean Surface ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Ocean Surface Layer
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