scholarly journals Dimethylated sulfur compounds in the Peruvian upwelling system

2021 ◽  
Author(s):  
Yanan Zhao ◽  
Dennis Booge ◽  
Christa A. Marandino ◽  
Cathleen Schlundt ◽  
Astrid Bracher ◽  
...  
Keyword(s):  
Surface Waters ◽  
Nitrogen Limitation ◽  
Trace Gas ◽  
Radical Scavengers ◽  
Upwelling System ◽  
Main Driver ◽  
Minimum Zone ◽  
Nitrate And Nitrite ◽  
Oxygen Minimum

Abstract. Our understanding of the biogeochemical cycling of the climate-relevant trace gas dimethylsulfide (DMS) in the Peruvian upwelling system is still limited. Here we present, oceanic and atmospheric DMS measurements which were made during two shipborne cruises in December 2012 (M91) and October 2015 (SO243) in the Peruvian upwelling region. Dimethylsulfoniopropionate (DMSP) and dimethylsulfoxide (DMSO) were also measured during M91. Relatively low DMS concentrations were measured in surface waters in October 2015 (1.9 ± 0.9 nmol L−1) and December 2012 (2.5 ± 1.9 nmol L−1). Nutrient availability appeared to be the main driver of the observed variability in the surface DMS distributions in the coastal areas. DMS, DMSP and DMSO showed maxima in the surface layer and no elevated concentrations associated with the oxygen minimum zone off Peru were measured. The possible role of DMS, DMSP and DMSO as radical scavengers (stimulated by nitrogen limitation) is supported by their negative correlations with N : P (sum of nitrate and nitrite: dissolved phosphate) ratios. Large variations in atmospheric DMS mole fractions were measured during M91 (144.6 ± 95.0 ppt) and SO243 (91.4 ± 55.8 ppt); however, the atmospheric mole fractions were generally low, and the sea-to-air flux density was primarily driven by seawater DMS. The Peruvian upwelling region was identified as a source of atmospheric DMS in December 2012 and October 2015, however, in comparison to the global monthly Lana climatology (mean: 6.2–9.8 μmol m−2 d−1 in October/December) (Lana et al., 2011), the Peru upwelling was not a hotspot of DMS emissions at either time (M91: 5.9 ± 5.3 μmol m−2 d−1; SO243: 3.8 ± 2.7 μmol m−2 d−1).

scholarly journals Insights into biotic and abiotic modulation of ocean mesopelagic communities

2021 ◽  
Author(s):  
Janaina Rigonato ◽  
Marko Budinich ◽  
Alejandro A. Murillo ◽  
Manoela C. Brandão ◽  
Juan J. Pierella Karlusich ◽  
...  
Keyword(s):  
Surface Waters ◽  
Network Inference ◽  
Biogeochemical Cycles ◽  
Environmental Drivers ◽  
Abiotic Factor ◽  
Marine Habitat ◽  
Mesopelagic Zone ◽  
Minimum Zone ◽  
Globally Distributed ◽  
Oxygen Minimum

AbstractMarine plankton mitigate anthropogenic greenhouse gases, modulate biogeochemical cycles, and provide fishery resources. Plankton is distributed across a stratified ecosystem of sunlit surface waters and a vast, though understudied, mesopelagic ‘dark ocean’. In this study, we mapped viruses, prokaryotes, and pico-eukaryotes across 32 globally-distributed cross-depth samples collected during the Tara Oceans Expedition, and assessed their ecologies. Based on depth and O2 measurements, we divided the marine habitat into epipelagic, oxic mesopelagic, and oxygen minimum zone (OMZ) eco-regions. We identified specific communities associated with each marine habitat, and pinpoint environmental drivers of dark ocean communities. Our results indicate that water masses primarily control mesopelagic community composition. Through co-occurrence network inference and analysis, we identified signature communities strongly associated with OMZ eco-regions. Mesopelagic communities appear to be constrained by a combination of factors compared to epipelagic communities. Thus, variations in a given abiotic factor may cause different responses in sunlit and dark ocean communities. This study expands our knowledge about the ecology of planktonic organisms inhabiting the mesopelagic zone.

Seasonal and Water Column Trends of the Relative Role of Nitrate and Nitrite as *OH Sources in Surface Waters

2007 ◽  
Vol 97 (8) ◽  
pp. 699-711 ◽  
Author(s):  
Davide Vione ◽  
Claudio Minero ◽  
Valter Maurino ◽  
Ezio Pelizzetti
Keyword(s):  
Water Column ◽  
Surface Waters ◽  
Relative Role ◽  
Nitrate And Nitrite

scholarly journals Controls on redox-sensitive trace metals in the Mauritanian oxygen minimum zone

2018 ◽  
Author(s):  
Insa Rapp ◽  
Christian Schlosser ◽  
Jan-Lukas Menzel Barraqueta ◽  
Bernhard Wenzel ◽  
Jan Lüdke ◽  
...  
Keyword(s):  
Community Structure ◽  
Trace Metals ◽  
Surface Waters ◽  
Oxygen Minimum Zones ◽  
Carbon And Nitrogen ◽  
Shelf Sediments ◽  
Minimum Zone ◽  
Ocean Carbon ◽  
Shelf Region ◽  
Oxygen Minimum

Abstract. The availability of the micronutrient iron (Fe) in surface waters determines primary production, N2 fixation and microbial community structure in large parts of the world's ocean, and thus plays an important role in ocean carbon and nitrogen cycles. Eastern boundary upwelling systems and the connected oxygen minimum zones (OMZs) are typically associated with elevated concentrations of redox-sensitive trace metals (e.g. Fe, manganese (Mn) and cobalt (Co)), with shelf sediments typically forming a key source. Over the last five decades, an expansion and intensification of OMZs has been observed and this trend is likely to proceed. However, it is unclear how trace metal (TM) distributions and transport are influenced by decreasing oxygen (O2) concentrations. Here we present dissolved (d;  0.2 μm) TM data collected at 7 stations along a 50 km transect in the Mauritanian shelf region. We observed enhanced concentrations of Fe, Co and Mn corresponding with low O2 concentrations (

scholarly journals Cryptic role of tetrathionate in the sulfur cycle: A study from Arabian Sea oxygen minimum zone sediments

2019 ◽  
Author(s):  
Subhrangshu Mandal ◽  
Sabyasachi Bhattacharya ◽  
Chayan Roy ◽  
Moidu Jameela Rameez ◽  
Jagannath Sarkar ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Potential Role ◽  
Sediment Cores ◽  
Oxygen Minimum Zone ◽  
Sulfur Cycle ◽  
Metagenome Analysis ◽  
Minimum Zone ◽  
Oxygen Minimum

ABSTRACTTo explore the potential role of tetrathionate in the sulfur cycle of marine sediments, the population ecology of tetrathionate-forming, oxidizing, and respiring microorganisms was revealed at 15-30 cm resolution along two, ∼3-m-long, cores collected from 530- and 580-mbsl water-depths of Arabian Sea, off India’s west coast, within the oxygen minimum zone (OMZ). Metagenome analysis along the two sediment-cores revealed widespread occurrence of the structural genes that govern these metabolisms; high diversity and relative-abundance was also detected for the bacteria known to render these processes. Slurry-incubation of the sediment-samples, pure-culture isolation, and metatranscriptome analysis, corroborated thein situfunctionality of all the three metabolic-types. Geochemical analyses revealed thiosulfate (0-11.1 μM), pyrite (0.05-1.09 wt %), iron (9232-17234 ppm) and manganese (71-172 ppm) along the two sediment-cores. Pyrites (via abiotic reaction with MnO2) and thiosulfate (via oxidation by chemolithotrophic bacteria prevalentin situ) are apparently the main sources of tetrathionate in this ecosystem. Tetrathionate, in turn, can be either converted to sulfate (via oxidation by the chemolithotrophs present) or reduced back to thiosulfate (via respiration by native bacteria); 0-2.01 mM sulfide present in the sediment-cores may also reduce tetrathionate abiotically to thiosulfate and elemental sulfur. Notably tetrathionate was not detectedin situ- high microbiological and geochemical reactivity of this polythionate is apparently instrumental in the cryptic nature of its potential role as a central sulfur cycle intermediate. Biogeochemical roles of this polythionate, albeit revealed here in the context of OMZ sediments, may well extend to the sulfur cycles of other geomicrobiologically-distinct marine sediment horizons.

scholarly journals Cryptic role of tetrathionate in the sulfur cycle: A study from Arabian Sea oxygen minimum zone sediments

2019 ◽  
Author(s):  
Subhrangshu Mandal ◽  
Sabyasachi Bhattacharya ◽  
Chayan Roy ◽  
Moidu Jameela Rameez ◽  
Jagannath Sarkar ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Potential Role ◽  
Sediment Cores ◽  
Oxygen Minimum Zone ◽  
Sulfur Cycle ◽  
Metagenome Analysis ◽  
Minimum Zone ◽  
Oxygen Minimum

Abstract. To explore the potential role of tetrathionate in the sulfur cycle of marine sediments, the population ecology of tetrathionate-forming, oxidizing, and respiring microorganisms was revealed at 15–30 cm resolution along two, ~ 3-m-long, cores collected from 530- and 580-mbsl water-depths of Arabian Sea, off India’s west coast, within the oxygen minimum zone (OMZ). Metagenome analysis along the two sediment-cores revealed widespread occurrence of the structural genes that govern these metabolisms; high diversity and relative-abundance was also detected for the bacteria known to render these processes. Slurry-incubation of the sediment-samples, pure-culture isolation, and metatranscriptome analysis, corroborated the in situ functionality of all the three metabolic-types. Geochemical analyses revealed thiosulfate (0–11.1 µM), pyrite (0.05–1.09 wt %), iron (9232–17234 ppm) and manganese (71–172 ppm) along the two sediment-cores. Pyrites (via abiotic reaction with MnO2) and thiosulfate (via oxidation by chemolithotrophic bacteria prevalent in situ) are apparently the main sources of tetrathionate in this ecosystem. Tetrathionate, in turn, can be either converted to sulfate (via oxidation by the chemolithotrophs present) or reduced back to thiosulfate (via respiration by native bacteria); 0–2.01 mM sulfide present in the sediment-cores may also reduce tetrathionate abiotically to thiosulfate and elemental sulfur. Notably tetrathionate was not detected in situ – high microbiological and geochemical reactivity of this polythionate is apparently instrumental in the cryptic nature of its potential role as a central sulfur cycle intermediate. Biogeochemical roles of this polythionate, albeit revealed here in the context of OMZ sediments, may well extend to the sulfur cycles of other geomicrobiologically-distinct marine sediment horizons.

scholarly journals Benthic Foraminifera from Middle to Late Pleistocene, coastal upwelling sediments of ODP Hole 686B, Pacific Ocean, off Peru

1991 ◽  
Vol 9 (2) ◽  
pp. 153-158 ◽  
Author(s):  
Kathryn A. Malmgren ◽  
Brian M. Funnell
Keyword(s):  
Late Pleistocene ◽  
Surface Waters ◽  
Benthic Foraminifera ◽  
Bottom Water ◽  
Coastal Upwelling ◽  
Oxygen Minimum Zone ◽  
Water Oxygen ◽  
Minimum Zone ◽  
Water Depths ◽  
Oxygen Minimum

Abstract. Benthic Foraminifera from middle to late Pleistocene, (c. 600ka to 0ka), sediments of ODP Hole 686B, off Peru, show highest abundances and diversities during periods of cooler surface waters, (inferred from the Uk37 index), and enhanced upwelling, (inferred from the peridinacean/gonyaulacacean dinoflagellate cyst ratio). During the latest Pleistocene, (c. 160ka to 0ka), these periods are characterised by higher organic carbon contents in the bottom sediments, and occur during the odd-numbered, interglacial_18O stages. The benthic Foraminifera indicate deposition in 120 to 250 metres water depth for the earlier part of the record, (c. 600ka to c. 200ka), within the oxygen-minimum zone, with bottom water oxygen contents of <0.5 to 0.2 ml/l, (inferred from the dominance of Bolivinellina humilis). Deposition in water depths approaching those of the present day, (c. 450 metres), is indicated from c. 160ka onwards, with better oxygenated bottom water conditions, probably corresponding to the lower part of the oxygen-minimum zone.

Oxygen-minimum zone edge effects: Evidence from the central California coastal upwelling system

Geology ◽  
1985 ◽  
Vol 13 (7) ◽  
pp. 491 ◽  
Author(s):  
Henry T. Mullins ◽  
Joel B. Thompson ◽  
Kristin McDougall ◽  
Thomas L. Vercoutere
Keyword(s):  
Edge Effects ◽  
Coastal Upwelling ◽  
Oxygen Minimum Zone ◽  
Central California ◽  
Upwelling System ◽  
Minimum Zone ◽  
Zone Edge ◽  
Oxygen Minimum

scholarly journals Distribution of Membrane Lipids of Planktonic Crenarchaeota in the Arabian Sea

2002 ◽  
Vol 68 (6) ◽  
pp. 2997-3002 ◽  
Author(s):  
Jaap S. Sinninghe Damsté ◽  
W. Irene C. Rijpstra ◽  
Ellen C. Hopmans ◽  
Fredrick G. Prahl ◽  
Stuart G. Wakeham ◽  
...  
Keyword(s):  
Surface Waters ◽  
Arabian Sea ◽  
Membrane Lipids ◽  
Oxygen Minimum Zone ◽  
Central Pacific ◽  
Central Pacific Ocean ◽  
Biological Studies ◽  
Intact Core ◽  
Minimum Zone ◽  
Oxygen Minimum

ABSTRACT Intact core tetraether membrane lipids of marine planktonic Crenarchaeota were quantified in water column-suspended particulate matter obtained from four depth intervals (∼70, 500, 1,000 and 1,500 m) at seven stations in the northwestern Arabian Sea to investigate the distribution of the organisms at various depths. Maximum concentrations generally occurred at 500 m, near the top of the oxygen minimum zone, and the concentrations at this depth were, in most cases, slightly higher than those in surface waters. In contrast, lipids derived from eukaryotes (cholesterol) and from eukaryotes and bacteria (fatty acids) were at their highest concentrations in surface waters. This indicates that these crenarchaeotes are not restricted to the photic zone of the ocean, which is consistent with the results of recent molecular biological studies. Since the Arabian Sea has a strong oxygen minimum zone between 100 and 1,000 m, with minimum oxygen levels of <1 μM, the abundance of crenarchaeotal membrane lipids at 500 m suggests that planktonic Crenarchaeota are probably facultative anaerobes. The cell numbers we calculated from the concentrations of membrane lipids are similar to those reported for the Central Pacific Ocean, supporting the recent estimation of M. B. Karner, E. F. DeLong, and D. M. Karl ( Nature 409 : 507-510, 2001 ) that the world's oceans contain ca. 1028 cells of planktonic Crenarchaeota.

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