Availability of Reduced Nitrogen Chemospecies in Photic-Zone Waters as the Ultimate Cause for Fossil Prasinophyte Prosperity

Prauss, Michael L.

doi:10.2110/palo.2005.p05-095r

Cited by 48 publications

(33 citation statements)

References 74 publications

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“…Because both fossil and geochemical records suggest that the major radiation of chlorophyll-a-and chlorophyll-c-producing algae occurred later in the Mesozoic and in the Cenozoic (Peters et al, 2005), we propose that at least part of the increased relative contribution of C 28 steranes derive from prasinophytes. This inference is consistent with our paleoredox reconstruction and N isotope data, because prasinophytes thrive in the presence of reduced N species associated with expanded OMZs (Prauss, 2007). Shifts in the distribution of eukaryotic plankton were accompanied by an increased contribution of hopane-producing cyanobacteria (2-MeHI) and methanotrophic bacteria (3-MeHI) following the ETE (i, j in Fig.…”

Section: Lipid Biomarkers As Indicators Of Planktonic Ecologysupporting

confidence: 90%

Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

Kasprak¹,

Sepúlveda²,

Price-Waldman³

et al. 2015

Geology

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Severe changes in ocean redox, nutrient cycling, and marine productivity accompanied most Phanerozoic mass extinctions. However, evidence for marine photic zone euxinia (PZE) as a globally important extinction mechanism for the end-Triassic extinction (ETE) is currently lacking. Fossil molecular (biomarker) and nitrogen isotopic records from a sedimentary sequence in western Canada provide the first conclusive evidence of PZE and disrupted biogeochemistry in neritic waters of the Panthalassic Ocean during the end Triassic. Increasing water-column stratification and deoxygenation across the ETE led to PZE in the Early Jurassic, paralleled by a perturbed nitrogen cycle and ecological turnovers among noncalcifying groups, including eukaryotic algae and prokaryotic plankton. If such conditions developed widely in the Panthalassic Ocean, PZE might have been a potent mechanism for the ETE.

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Section: Lipid Biomarkers As Indicators Of Planktonic Ecologysupporting

confidence: 90%

Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

Kasprak¹,

Sepúlveda²,

Price-Waldman³

et al. 2015

Geology

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“…Prasinophyte phycomata and peridinioid dinoflagellate cysts are the dominant palynomorphs. It has been suggested that the input or availability of reduced nitrogen from the denitrification zone into photic-zone waters may have selectively stimulated groups of green algae like prasinophytes in the CenomanianÀTuronian organic-rich shales of Germany and Tarfaya, Morocco (Prauss 2006(Prauss , 2007(Prauss , 2012a and references therein). In Tarfaya, significant water-column oxygen depletion has been inferred, episodically reaching up into to the photic zone (Kolonic et al 2005).…”

Section: Palaeoenvironmentsmentioning

confidence: 99%

“…During deposition of the Lower Eagle Ford Formation, the introduction of waters from respectively deeper denitrification zones into photic zone waters by upwelling, or vertical expansion of the oxygen-minimum zone, may have fostered the prosperity of peridinioids and prasinophytes by enhanced availability of nitrite (peridinioids) and ammonium (prasinophytes; cf. Prauss 2007). Prauss (2012aPrauss ( , 2012b recorded sporadically common/abundant occurrences of the peridinioid taxon Bosedinia sp.…”

Section: Palaeoenvironmentsmentioning

confidence: 99%

Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Dodsworth¹

2015

Palynology

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This study describes the detailed palynology of the Eagle Ford Group at Lozier Canyon, its principal outcrop reference section in west Texas. Prominent marine phytoplankton assemblages are consistent with a proposed depositional setting for Lozier Canyon on a submarine platform within the Cretaceous Western Interior Seaway (KWIS) of the USA. The Lower Eagle Ford Formation (middle to upper Cenomanian) was deposited under restricted marine conditions with oxygen-deficient, probably anoxic bottom waters, as indicated by the black, organic-rich (ca. 1 to > 6% total organic carbon) shale lithology. The formation comprises two fourth-order stratigraphical sequences, each showing sedimentary evidence of increasing water depth during deposition. Palynomorph assemblages from the sequences are dominated by green algal prasinophyte phycomata in the lower parts and peridinioid dinoflagellate cysts in the upper parts. The productivity of these marine phytoplankton groups may have been stimulated by availability of ammonium (prasinophytes) and nitrite (peridinioids) from upwelling, or vertical expansion of the oxygen-minimum zone. The transition from prasinophyte-to peridinioid-dominated assemblages may reflect elevation of the photic zone to a level less regularly encroached by deeper, ammonium-enriched waters of the denitrification zone. The overlying Upper Eagle Ford Formation (upper Cenomanian to upper Turonian or Coniacian) was deposited under deeper, relatively open marine conditions, as indicated by a decrease in organic carbon content and an increase in carbonate content. This is supported by the presence of diversified dinoflagellate cyst assemblages, including inter-regional (high-to mid-latitude) marker events; in the upper Cenomanian, base and acme Cyclonephelium compactum-membraniphorum, top consistent and frequent Litosphaeridium siphoniphorum, and top Adnatosphaeridium tutulosum; in the middle to upper Turonian, range bases of Heterosphaeridium difficile and Senoniasphaera rotundata. The stratigraphical resolution offered by palynology indicates potential application to wellsite 'geosteering' of commercial shale oil and shale gas wells drilled in the Eagle Ford Group.

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“…Alternatively, they could withstand periods when dysoxic-anoxic, probably even euxinic, conditions reached the photic zone. Furthermore, they were better adapted to the reduced recycling of nutrients that sank to the bottom, and could not return to the photic zone due to density stratification of the water column (Farrimond et al, 1989;Prauss, 2007).…”

Section: Intervalmentioning

confidence: 99%

“…However, the reasons for their proliferation during anoxic events, including their widespread distribution at the T-OAE, are still controversial. Prauss (2007) summarised the probable causes of prasinophyte abundance during anoxic events (e.g. the T-OAE and the Cenomanian/Turonian event).…”

Section: Intervalmentioning

confidence: 99%

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

Baranyi

Pálfy

Görög

et al. 2016

Review of Palaeobotany and Palynology

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Major palaeoenvironmental and palaeoceanographical changes occurred during the Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE), due to a perturbation of the global carbon cycle and a crisis in marine ecosystems. The sequence of environmental change and regional differences during the T-OAE are not yet fully understood and organic-walled phytoplankton and other palynomorphs are well-suited, but under-utilised, in research into this event. Based on quantitative palynological analyses from a black shale-bearing succession at Réka Valley in the Mecsek Mountains of southwest Hungary, five sequential palynomorph assemblages are distinguished. These reveal major shifts in organic-walled phytoplankton communities, driven by palaeoenvironmental changes. In addition, palynofacies analysis helped to document changes in the composition of sedimentary organic matter, and to quantify the terrestrial input. Assemblage 1 is characterised by a moderately diverse phytoplankton community and high levels of terrestrial palynomorphs. Assemblage 2 records a significant peak of the euryhaline dinoflagellate cyst Nannoceratopsis. Assemblage 3 is distinguished by dominance of highly opportunistic prasinophytes and the temporary disappearance of all dinoflagellate cyst taxa. Assemblages 4 and 5 represent distinctive phases of a prolonged recovery phase with low diversity phytoplankton assemblages and intermittently high levels of terrestrially-derived palynomorphs. The successive disappearance of phytoplankton taxa and the gradual takeover by opportunistic euryhaline species at the onset of the T-OAE were related to several phenomena. These include reduced salinity in the surface waters, establishment of a stable pycnocline and deterioration of nutrient recycling, followed by oxygen deficiency throughout much of the water column. The high amount of terrestrially-derived palynodebris indicates intense runoff and freshwater input, driven by the early Toarcian warming and the enhanced hydrological cycle. Comparison with coeval European successions proves that the palaeoenvironmental changes during the T-OAE were not entirely synchronous, and local factors played a crucial role in influencing phytoplankton communities. In the Mecsek Basin, regional freshening of the surface waters and increased terrestrial input due to the proximity of the hinterland had a greater influence on phytoplankton communities compared to the open oceanic setting of the Tethys to the south.

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Availability of Reduced Nitrogen Chemospecies in Photic-Zone Waters as the Ultimate Cause for Fossil Prasinophyte Prosperity

Cited by 48 publications

References 74 publications

Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction

Palynostratigraphy and palaeoenvironments of the Eagle Ford Group (Upper Cretaceous) at the Lozier Canyon outcrop reference section, west Texas, USA

Multiphase response of palynomorphs to the Toarcian Oceanic Anoxic Event (Early Jurassic) in the Réka Valley section, Hungary

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