scholarly journals Correlation of <i>Virgulinella fragilis</i> Grindell & Collen (benthic foraminiferid) with near-anoxia in Aso-kai Lagoon, central Japan

2005 ◽  
Vol 24 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Hiroyuki Takata ◽  
Koji Seto ◽  
Saburo Sakai ◽  
Satoshi Tanaka ◽  
Katsumi Takayasu
Keyword(s):  
Cluster Analysis ◽  
Pore Water ◽  
Coastal Lagoon ◽  
Bottom Water ◽  
Low Oxygen ◽  
Central Japan ◽  
Reactive Iron ◽  
Predominant Species ◽  
Oxygen Conditions ◽  
Cluster A

Abstract. The distribution of Virgulinella fragilis and the hydro-environment of Aso-kai Lagoon, central Japan, were studied to clarify the foraminifer’s adaptation to low-oxygen conditions. The hypolimnion of the lagoon is oxygen-poor during much of the year. Two faunas (A and B) are recognized, based on cluster analysis. Cluster A fauna consists of species common in brackish lagoons, such as the genera Trochammina and Ammonia, and occurs in seasonally oxygenated waters. Virgulinella fragilis, the predominant species of Cluster B fauna, dominates the central part of the lagoon. This species can tolerate more severe oxygen deficiencies than the typical brackish foraminifers (e.g. Trochammina spp.) and can adapt to long periods of oxygen-poor conditions in coastal lagoon environments, as well as in pelagic to hemi-pelagic settings. In order to survive in the near-anoxia of Aso-kai Lagoon, V. fragilis may have adapted to environments in which little reactive iron is available in the sediment, leaving pore-water and bottom-water sulphide available for symbionts, or may utilize sulphur denitrification processes.

scholarly journals A comparison of benthic foraminiferal Mn / Ca and sedimentary Mn / Al as proxies of relative bottom-water oxygenation in the low-latitude NE Atlantic upwelling system

2015 ◽  
Vol 12 (18) ◽  
pp. 5415-5428 ◽  
Author(s):  
C. L. McKay ◽  
J. Groeneveld ◽  
H. L. Filipsson ◽  
D. Gallego-Torres ◽  
M. J. Whitehouse ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Bottom Water ◽  
Secondary Ion Mass Spectrometry ◽  
Younger Dryas ◽  
Icp Oes ◽  
Low Oxygen ◽  
Ne Atlantic ◽  
Low Latitude ◽  
Upwelling System ◽  
Oxygen Conditions

Abstract. Trace element incorporation into foraminiferal shells (tests) is governed by physical and chemical conditions of the surrounding marine environment, and therefore foraminiferal geochemistry provides a means of palaeo-oceanographic reconstructions. With the availability of high-spatial-resolution instrumentation with high precision, foraminiferal geochemistry has become a major research topic over recent years. However, reconstructions of past bottom-water oxygenation using foraminiferal tests remain in their infancy. In this study we explore the potential of using Mn / Ca determined by secondary ion mass spectrometry (SIMS) as well as by flow-through inductively coupled plasma optical emission spectroscopy (FT-ICP-OES) in the benthic foraminiferal species Eubuliminella exilis as a proxy for recording changes in bottom-water oxygen conditions in the low-latitude NE Atlantic upwelling system. Furthermore, we compare the SIMS and FT-ICP-OES results with published Mn sediment bulk measurements from the same sediment core. This is the first time that benthic foraminiferal Mn / Ca is directly compared with Mn bulk measurements, which largely agree on the former oxygen conditions. Samples were selected to include different productivity regimes related to Marine Isotope Stage 3 (35–28 ka), the Last Glacial Maximum (28–19 ka), Heinrich Event 1 (18–15.5 ka), Bølling Allerød (15.5–13.5 ka) and the Younger Dryas (13.5–11.5 ka). Foraminiferal Mn / Ca determined by SIMS and FT-ICP-OES is comparable. Mn / Ca was higher during periods with high primary productivity, such as during the Younger Dryas, which indicates low-oxygen conditions. This is further supported by the benthic foraminiferal faunal composition. Our results highlight the proxy potential of Mn / Ca in benthic foraminifera from upwelling systems for reconstructing past variations in oxygen conditions of the sea floor environment as well as the need to use it in combination with other proxy records such as faunal assemblage data.

scholarly journals A comparison of benthic foraminiferal Mn/Ca and sedimentary Mn/Al as proxies of relative bottom water oxygenation in the low latitude NE Atlantic upwelling system

2015 ◽  
Vol 12 (10) ◽  
pp. 7335-7367 ◽  
Author(s):  
C. L. McKay ◽  
J. Groeneveld ◽  
H. L. Filipsson ◽  
D. Gallego-Torres ◽  
M. Whitehouse ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Bottom Water ◽  
Younger Dryas ◽  
Bulk Sediment ◽  
Icp Oes ◽  
Low Oxygen ◽  
Ne Atlantic ◽  
Low Latitude ◽  
Upwelling System ◽  
Oxygen Conditions

Abstract. Trace element incorporation into foraminiferal shells (tests) is governed by physical and chemical conditions of the surrounding marine environment and therefore foraminiferal geochemistry provides a means of palaeoceanographic reconstructions. With the availability of high spatial resolution instrumentation with high precision, foraminiferal geochemistry has become a major research topic over recent years. However, reconstructions of past bottom water oxygenation using foraminiferal tests remain in their infancy. In this study we explore the potential of using Mn/Ca determined by Secondary Ion Mass Spectrometry (SIMS) as well as by Flow-Through Inductively Coupled Plasma Optical Emission Spectroscopy (FT-ICP-OES) in the benthic foraminiferal species Eubuliminella exilis as a proxy for recording changes in bottom water oxygen conditions in the low latitude NE Atlantic upwelling system. Furthermore, we compare the SIMS and FT-ICP-OES results with published Mn/Al in the bulk sediment from the same sediment core. This is the first time that benthic foraminiferal Mn/Ca is directly compared with Mn/Al in the bulk sediment, which largely agree on the former oxygen conditions. Samples were selected to include different productivity regimes related to Marine Isotope Stage 3 (35–28 ka), the Last Glacial Maximum (28–19 ka), Heinrich Event 1 (18–15.5 ka), Bølling Allerød (15.5–13.5 ka) and the Younger Dryas (13.5–11.5 ka). Foraminiferal Mn/Ca determined by SIMS and FT-ICP-OES are comparable. Mn/Ca was higher during periods with high primary productivity, such as during the Younger Dryas which indicates low oxygen conditions. This is further supported by the benthic foraminiferal faunal composition. Our results highlight the proxy potential of Mn/Ca in benthic foraminifera from upwelling systems for reconstructing past variations in oxygen conditions of the sea floor environment as well as the need to use it in combination with other proxy records such as faunal assemblage data.

The influence of bottom water intrusion events on the biogeochemistry of a coastal fjord

2020 ◽  
Author(s):  
Subhadeep Rakshit ◽  
Andrew Cogswell ◽  
Sebastian Haas ◽  
Emmanuel Devred ◽  
Richard Davis ◽  
...  
Keyword(s):  
Reactive Transport ◽  
Bottom Water ◽  
Water Exchange ◽  
Transport Model ◽  
Biogeochemical Processes ◽  
Low Oxygen ◽  
Eastern Canada ◽  
Oxygen Conditions ◽  
Bottom Waters ◽  
The Impact

&lt;p&gt;Lack of bottom water exchange in fjord-like estuaries can result in low oxygen conditions and creating sites of redox-sensitive biogeochemical processes, such as denitrification. In many of these systems, occasional intrusions of well-oxygenated bottom water may temporarily alter redox gradients and sediment-water biogeochemistry. Quantifying the magnitude and importance of these changes is a challenge due to the short timescales over which these events can occur. Here we present results from Bedford Basin, a 71 m deep coastal fjord in eastern Canada, where a 20-year, weekly timeseries of bottom water conditions indicates that autumn wind-driven intrusion events are a common, but infrequent, feature of its circulation. To examine the impact of these intrusions on biogeochemistry, we deployed a benthic instrument pod at 60 m depth to record high-resolution measurements of temperature, salinity, nitrate, oxygen, and fluorescence over a 4-month period during the fall of 2018.&amp;#160; During this time we captured two intrusion events, one in mid-Oct and another in mid-Nov. Both intrusion events occurred on a timescale of hours and resulted in sharp changes in temperature, salinity, oxygen, and nitrate.&amp;#160; We used these measurements to constrain a coupled sediment-water column reactive transport model to examine the immediate and annual impacts of these intrusion events on oxygen and nitrogen dynamics in the basin bottom waters and across the sediment-water interface.&lt;/p&gt;

Sedimentary trace metals: improving proxies for deoxygenation in coastal European seas

2021 ◽  
Author(s):  
Mareike Paul ◽  
Niels A. G. M. van Helmond ◽  
Caroline P. Slomp ◽  
Sami A. Jokinen ◽  
Joonas J. Virtasalo ◽  
...  
Keyword(s):  
Trace Metals ◽  
Trace Metal ◽  
Bottom Water ◽  
Depositional Environments ◽  
Coastal Zones ◽  
Low Oxygen ◽  
Coastal Marine ◽  
Oxygen Conditions ◽  
History Of ◽  
Metal Redox

&lt;p&gt;Deoxygenation in response to eutrophication and climate change in coastal systems is increasing worldwide. Low oxygen conditions cause the chemical transformation of redox-sensitive trace metals (e.g. molybdenum and uranium) in seawater, and their subsequent transport to the sediment. Sedimentary trace metal contents can therefore be used as a record of changes in bottom water oxygen conditions allowing the history of deoxygenation to be reconstructed. However, most trace metal studies have focused on strongly reducing and sulfidic settings, leaving mildly reducing and oxygenated (but eutrophic) settings vastly understudied. Currently, it is unknown to what extent existing trace metal redox proxies are applicable to reconstruct oxygen conditions in coastal zones experiencing mild deoxygenation, despite the fact that such areas occupy vast stretches of the coastal oceans. Here, we study trace metal enrichments in 13 European coastal marine sites with varying bottom water redox conditions and depositional environments. Our data demonstrates that sedimentary molybdenum and uranium contents are sensitive to deoxygenation across a range of settings, although the mechanisms of enrichment may vary. Improved understanding of molybdenum and uranium dynamics in mildly reducing coastal settings will facilitate the development of reliable and widely applicable molybdenum and uranium-based redox proxies.&lt;/p&gt;

scholarly journals Mn∕Ca intra- and inter-test variability in the benthic foraminifer <i>Ammonia tepida</i>

2018 ◽  
Vol 15 (1) ◽  
pp. 331-348 ◽  
Author(s):  
Jassin Petersen ◽  
Christine Barras ◽  
Antoine Bézos ◽  
Carole La ◽  
Lennart J. de Nooijer ◽  
...  
Keyword(s):  
Pore Water ◽  
Sediment Geochemistry ◽  
Reduced Form ◽  
Pore Waters ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
Vital Effects ◽  
Seasonal Hypoxia ◽  
Test Variability ◽  
Lake Grevelingen

Abstract. The adaptation of some benthic foraminiferal species to low-oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy because this redox element is soluble in reduced form (Mn2+) and hence can be incorporated into benthic foraminiferal tests under low-oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn∕Ca ratios may hold important information about short-term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn∕Ca intra- and inter-test variability in living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (the Netherlands) in three different months of 2012. The deeper parts of this lake are characterized by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intra-test variability due to ontogenetic trends (i.e. size-related effects) and/or other vital effects occurring during calcification in A. tepida (11–25 % relative SD, RSD) is responsible for part of the observed variability in Mn∕Ca. Our present results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn∕Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn∕Ca ratios with size are observed. Our results suggest that the variability in successive single-chamber Mn∕Ca ratios reflects the temporal variability in pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn∕Ca variability.

scholarly journals Mn / Ca intra-test variability in the benthic foraminifer <i>Ammonia tepida</i>

2017 ◽  
Author(s):  
Jassin Petersen ◽  
Christine Barras ◽  
Antoine Bézos ◽  
Carole La ◽  
Lennart J. de Nooijer ◽  
...  
Keyword(s):  
Pore Water ◽  
Sediment Geochemistry ◽  
Reduced Form ◽  
Pore Waters ◽  
Low Oxygen ◽  
Short Term ◽  
Oxygen Conditions ◽  
Seasonal Hypoxia ◽  
Test Variability ◽  
Lake Grevelingen

Abstract. The adaptation of some benthic foraminiferal species to low oxygen conditions provides the prospect of using the chemical composition of their tests as proxies for bottom water oxygenation. Manganese may be particularly suitable as such a geochemical proxy, because this redox element is soluble in reduced form (Mn2+), and hence can be incorporated into benthic foraminiferal tests under low oxygen conditions. Therefore, intra- and inter-test differences in foraminiferal Mn / Ca ratios may hold important information about short term variability in pore water Mn2+ concentrations and sediment redox conditions. Here, we studied Mn / Ca inter- and intra-test variability of living individuals of the shallow infaunal foraminifer Ammonia tepida sampled in Lake Grevelingen (The Netherlands) in three different months of 2012. The deeper parts of this lake are characterised by seasonal hypoxia/anoxia with associated shifts in microbial activity and sediment geochemistry, leading to seasonal Mn2+ accumulation in the pore water. Earlier laboratory experiments with similar seawater Mn2+ concentrations as encountered in the pore waters of Lake Grevelingen suggest that intrinsic intra-test variability in A. tepida (11–25 % RSD) is responsible for a considerable portion of the observed variability in Mn / Ca. Our results show that the seasonally highly dynamic environmental conditions in the study area lead to a strongly increased Mn / Ca intra- and inter-test variability (average of 45 % RSD). Within single specimens, both increasing and decreasing trends in Mn / Ca ratios with size are observed. Our results suggest that the variability of successive single chamber Mn / Ca ratios reflects the temporal variability of pore water Mn2+. Additionally, active or passive migration of the foraminifera in the surface sediment may explain part of the observed Mn / Ca variability.

scholarly journals Identification and Functional Analysis of ThADH1 and ThADH4 Genes Involved in Tolerance to Waterlogging Stress in Taxodium hybrid ‘Zhongshanshan 406’

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 225
Author(s):  
Lei Xuan ◽  
Jianfeng Hua ◽  
Fan Zhang ◽  
Zhiquan Wang ◽  
Xiaoxiao Pei ◽  
...  
Keyword(s):  
Ethanol Metabolism ◽  
Flooding Tolerance ◽  
Transcriptome Data ◽  
Low Oxygen ◽  
Anaerobic Conditions ◽  
Waterlogging Tolerance ◽  
Waterlogging Stress ◽  
Adh Genes ◽  
Oxygen Conditions ◽  
Stems And Leaves

The Taxodium hybrid ‘Zhongshanshan 406’ (T. hybrid ‘Zhongshanshan 406’) [Taxodium mucronatum Tenore × Taxodium distichum (L.). Rich] has an outstanding advantage in flooding tolerance and thus has been widely used in wetland afforestation in China. Alcohol dehydrogenase genes (ADHs) played key roles in ethanol metabolism to maintain energy supply for plants in low-oxygen conditions. Two ADH genes were isolated and characterized—ThADH1 and ThADH4 (GenBank ID: AWL83216 and AWL83217—basing on the transcriptome data of T. hybrid ‘Zhongshanshan 406’ grown under waterlogging stress. Then the functions of these two genes were investigated through transient expression and overexpression. The results showed that the ThADH1 and ThADH4 proteins both fall under ADH III subfamily. ThADH1 was localized in the cytoplasm and nucleus, whereas ThADH4 was only localized in the cytoplasm. The expression of the two genes was stimulated by waterlogging and the expression level in roots was significantly higher than those in stems and leaves. The respective overexpression of ThADH1 and ThADH4 in Populus caused the opposite phenotype, while waterlogging tolerance of the two transgenic Populus significantly improved. Collectively, these results indicated that genes ThADH1 and ThADH4 were involved in the tolerance and adaptation to anaerobic conditions in T. hybrid ‘Zhongshanshan 406’.

Pilot-scale production of cloudy juice from low-quality pear fruit under low-oxygen conditions

2015 ◽  
Vol 173 ◽  
pp. 827-837 ◽  
Author(s):  
Domien De Paepe ◽  
Katleen Coudijzer ◽  
Bart Noten ◽  
Dirk Valkenborg ◽  
Kelly Servaes ◽  
...  
Keyword(s):  
Pilot Scale ◽  
Scale Production ◽  
Low Oxygen ◽  
Pear Fruit ◽  
Pilot Scale Production ◽  
Oxygen Conditions
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