Recurring photic zone euxinia in the northwest Tethys impinged end-Triassic extinction recovery

ABSTRACT Gedl, P., Kaim, A., Leonowicz, P., Boczarowski, A., Dudek, T., Kędzierski, M., Rees, J., Smoleń, J., Szczepanik, P., Sztajner, P., Witkowska, M. and Ziaja, J. 2012. Palaeoenvironmental reconstruction of Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Krakow-Silesia Homocline, Poland. Acta Geologica Polonica, 62(3), 463-484. Warszawa. Multidisciplinary studies of the Middle-Upper Bathonian ore-bearing clays at Gnaszyn revealed variable palaeoenvironmental conditions during the deposition of this seemingly monotonous sequence. We interpret the conditions in the bottom environment and the photic zone, and also evaluate the influence of the adjacent land areas, based on sedimentology, geochemistry, sporomorphs and palynofacies composition, benthic (foraminifera, gastropods, bivalves, scaphopods, echinoderms), planktonic (calcareous nannoplankton, dinoflagellate cysts), and nektonic (sharks) fossils. The Gnaszyn succession originated relatively close to the shore, within reach of an intense supply of terrestrial fine clastic and organic particles. The latter are mainly of terrestrial origin and range from 1.5 to 2.5 wt.%. The precise water depth is difficult to estimate but most likely ranges from several tens of metres to a few hundred metres. All fossil groups show minor changes throughout the succession. As the climate seems to have been quite stable during this period we consider sea-level fluctuations to have been the main factor responsible for the changes. The terrestrial input, including freshwater and land-derived clastic and organic particles (sporomorphs and cuticles), increased during periods of sea-level lowstand. As a consequence, stress conditions (lower salinity, higher nutrient availability, lower water transparency) in the photic zone caused blooms of opportunistic planktonic taxa. Furthermore, a faster sedimentation rate led to oxygen depletion and deterioration of the living conditions in the bottom environment due to an increased accumulation of organic matter. As a result, the benthic biota became taxonomically impoverished and commonly dominated by juvenile forms. During periods of high sea level, the source areas were shifted away from the basin, resulting in a decrease in the terrestrial influx, increase in the salinity of surface waters, the appearance of more diverse phytoplankton assemblages, a lower sedimentation rate, and an improvement of living conditions at the bottom.

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A Review of Protist Grazing Below the Photic Zone Emphasizing Studies of Oxygen-Depleted Water Columns and Recent Applications of In situ Approaches

Frontiers in Marine Science ◽

10.3389/fmars.2017.00105 ◽

2017 ◽

Vol 4 ◽

Cited By ~ 3

Author(s):

Luis E. Medina ◽

Craig D. Taylor ◽

Maria G. Pachiadaki ◽

Carlos Henríquez-Castillo ◽

Osvaldo Ulloa ◽

...

Keyword(s):

Photic Zone ◽

Water Columns

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Diatoms as a paleoproductivity proxy in the NW Iberian coastal upwelling system (NE Atlantic)

Biogeosciences ◽

10.5194/bg-14-1165-2017 ◽

2017 ◽

Vol 14 (5) ◽

pp. 1165-1179 ◽

Cited By ~ 8

Author(s):

Diana Zúñiga ◽

Celia Santos ◽

María Froján ◽

Emilia Salgueiro ◽

Marta M. Rufino ◽

...

Keyword(s):

Water Column ◽

Surface Sediment ◽

Sediment Trap ◽

Coastal Upwelling ◽

Late Summer ◽

Early Summer ◽

Marine Diatom ◽

Photic Zone ◽

Upwelling System ◽

Water Column Stratification

Abstract. The objective of the current work is to improve our understanding of how water column diatom's abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 (±5.6) 106 valves m−2 d−1) represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom-derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Furthermore, Chaetoceros spp. dominate during spring–early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment's total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes.

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Erratum to “A Perspective on Stratigraphic, Vertically-Upward “Displacements or Dislocations” of Conodont-Elements: An Example From the Upper Devonian, Pre-Lithified, Black Shales of the Chattanooga Shale Formation In Tennessee, USA” ...

Earth Science Research ◽

10.5539/esr.v9n1p14 ◽

2019 ◽

Vol 9 (1) ◽

pp. 14

Author(s):

Michael Iannicelli

Keyword(s):

Black Shale ◽

Environmental Chemistry ◽

Black Shales ◽

Photic Zone ◽

Marine Organic Matter ◽

Chattanooga Shale ◽

Shale Formation ◽

Organic Matter Biomarkers ◽

Reference Section ◽

Made In

Even though the author already incorporated the citation of Sinninghe-Damste & Schouten (2006) into the text of the paper, the author regrets having failed to include their full citation within the Reference Section of my above paper which is: Sinninghe-Damste, J. S. & Schouton, S. (2006). Biological markers for anoxia in the photic zone of the water column. In, Volkman, J. K. (ed.), Marine Organic Matter: Biomarkers, Isotopes and DNA, (pp. 127 – 163). The Handbook of Environmental Chemistry, vol. 2N. Springer: Berlin and Heidelberg. https://doi.org/10.1007/698_2_005 The author also needs to paraphrase a statement made in the last three lines of the 2nd paragraph on page 40 where it reads as: “Thus, we may conclude here that paleo-upfreezing of any conodont-element(s) originally buried in the pre-lithified, light-colored shale occurred in order to account for their presence in black shale”. Instead, in lieu of that statement, it should read as “At this point in time of the study, we may tentatively conclude here while completely concluding later in the study, that conodont-elements originally existing in the underlying, pre-lithified, light-colored shale, had to paleo-upfreeze vertically upward into pre-lithified, black shale sediment in order to account for their presence in lithified black shale”.

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Solisphaera gen. nov. (Prymnesiophyceae), a new coccolithophore genus from the lower photic zone

Phycologia ◽

10.2216/05-14.1 ◽

2006 ◽

Vol 45 (4) ◽

pp. 465-477 ◽

Cited By ~ 6

Author(s):

Jörg Bollmann ◽

Mara Y. Cortés ◽

Annelies Kleijne ◽

Jette B. Østergaard ◽

Jeremy R. Young

Keyword(s):

Photic Zone

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Genome Analysis of a Marine Bacterium Halomonas sp. and Its Role in Nitrate Reduction under the Influence of Photoelectrons

Microorganisms ◽

10.3390/microorganisms8101529 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1529

Author(s):

Ying Liu ◽

Hongrui Ding ◽

Yuan Sun ◽

Yan Li ◽

Anhuai Lu

Keyword(s):

Genome Analysis ◽

Nitrate Reduction ◽

Nitrogen Loss ◽

Light Response ◽

Open Circuit ◽

The Yellow Sea ◽

Photic Zone ◽

Whole Genome Analysis ◽

Genes Encoding ◽

Assimilatory Nitrate Reduction

The solar light response and photoelectrons produced by widespread semiconducting mineral play important roles in biogeochemical cycles on Earth’s surface. To explore the potential influence of photoelectrons generated by semiconducting mineral particles on nitrate-reducing microorganisms in the photic zone, a marine heterotrophic denitrifier Halomonas sp. strain 3727 was isolated from seawater in the photic zone of the Yellow Sea, China. This strain was classified as a Halomonadaceae. Whole-genome analysis indicated that this strain possessed genes encoding the nitrogen metabolism, i.e., narG, nasA, nirBD, norZ, nosB, and nxr, which sustained dissimilatory nitrate reduction, assimilatory nitrate reduction, and nitrite oxidation. This strain also possessed genes related to carbon, sulfur, and other metabolisms, hinting at its substantial metabolic flexibility. A series of microcosm experiments in a simulative photoelectron system was conducted, and the results suggested that this bacterial strain could use simulated photoelectrons with different energy for nitrate reduction. Nitrite, as an intermediate product, was accumulated during the nitrate reduction with limited ammonia residue. The nitrite and ammonia productions differed with or without different energy electron supplies. Nitrite was the main product accounting for 30.03% to 68.40% of the total nitrogen in photoelectron supplement systems, and ammonia accounted for 3.77% to 8.52%. However, in open-circuit systems, nitrite and ammonia proportions were 26.77% and 11.17%, respectively, and nitrogen loss in the liquid was not observed. This study reveals that photoelectrons can serve as electron donors for nitrogen transformation mediated by Halomonas sp. strain 3727, which reveals an underlying impact on the nitrogen biogeochemical cycle in the marine photic zone.

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