Changes in sulfur cycling in a large lake during the Paleocene-Eocene Thermal Maximum and implications for lake deoxygenation

Abstract. Enormous amounts of 13C-depleted carbon rapidly entered the exogenic carbon cycle during the onset of the Paleocene-Eocene thermal maximum (PETM), as attested to by a prominent negative carbon isotope (δ13C) excursion and deep-sea carbonate dissolution. A widely cited explanation for this carbon input has been thermal dissociation of gas hydrate on continental slopes, followed by release of CH4 from the seafloor and its subsequent oxidation to CO2 in the ocean or atmosphere. Increasingly, papers have argued against this mechanism, but without fully considering existing ideas and available data. Moreover, other explanations have been presented as plausible alternatives, even though they conflict with geological observations, they raise major conceptual problems, or both. Methane release from gas hydrates remains a congruous explanation for the δ13C excursion across the PETM, although it requires an unconventional framework for global carbon and sulfur cycling, and it lacks proof. These issues are addressed here in the hope that they will prompt appropriate discussions regarding the extraordinary carbon injection at the start of the PETM and during other events in Earth's history.

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The Current Supplement, The Shallowest Large Lake, and more

Scientific American ◽

10.1038/scientificamerican09241910-238a ◽

1910 ◽

Vol 103 (13) ◽

pp. 238-238

Keyword(s):

Large Lake

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Boron proxy constraints on the magnitude of surface ocean acidification during the Paleocene-Eocene Thermal Maximum

Rendiconti online della Società Geologica Italiana ◽

10.3301/rol.2014.106 ◽

2014 ◽

Vol 31 ◽

pp. 173-174

Author(s):

Donald E. Penman

Keyword(s):

Ocean Acidification ◽

Surface Ocean ◽

Thermal Maximum

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Dealing with hot rocky environments: Critical thermal maxima and locomotor performance in Leptodactylus lithonaetes (Anura: Leptodactylidae)

Herpetological Journal ◽

10.33256/hj29.3.155161 ◽

2019 ◽

pp. 155-161 ◽

Cited By ~ 1

Author(s):

Ivan Beltran

Keyword(s):

Environmental Temperature ◽

Extreme Temperature ◽

Effect Of Temperature ◽

Maximum Speed ◽

Locomotor Performance ◽

Extreme Temperatures ◽

Physiological Limits ◽

Fitness Consequences ◽

Thermal Maximum ◽

Environmental Temperatures

Environmental temperature has fitness consequences on ectotherm development, ecology and behaviour. Amphibians are especially vulnerable because thermoregulation often trades with appropriate water balance. Although substantial research has evaluated the effect of temperature in amphibian locomotion and physiological limits, there is little information about amphibians living under extreme temperature conditions. Leptodactylus lithonaetes is a frog allegedly specialised to forage and breed on dark granitic outcrops and associated puddles, which reach environmental temperatures well above 40 ˚C. Adults can select thermally favourable microhabitats during the day while tadpoles are constrained to rock puddles and associated temperature fluctuations; we thus established microhabitat temperatures and tested whether the critical thermal maximum (CTmax) of L. lithonaetes is higher in tadpoles compared to adults. In addition, we evaluated the effect of water temperature on locomotor performance of tadpoles. Contrary to our expectations, puddle temperatures were comparable and even lower than those temperatures measured in the microhabitats used by adults in the daytime. Nonetheless, the CTmax was 42.3 ˚C for tadpoles and 39.7 ˚C for adults. Regarding locomotor performance, maximum speed and maximum distance travelled by tadpoles peaked around 34 ˚C, approximately 1 ˚C below the maximum puddle temperatures registered in the puddles. In conclusion, L. lithonaetes tadpoles have a higher CTmax compared to adults, suggesting a longer exposure to extreme temperatures that lead to maintain their physiological performance at high temperatures. We suggest that these conditions are adaptations to face the strong selection forces driven by this granitic habitat.

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Aquatic and helophyte vegetation of the Donty Lake (The Komi Republic)

Vegetation of Russia ◽

10.31111/vegrus/2008.12.76 ◽

2008 ◽

pp. 76-85 ◽

Cited By ~ 6

Author(s):

B. Yu. Teteryuk

Keyword(s):

Plant Communities ◽

Rare Species ◽

Komi Republic ◽

European Part ◽

Large Lake ◽

Hydrophytic Vegetation ◽

North East ◽

European Part Of Russia

The results of a syntaxonomical study of plant communities of the large lake Donty (North-East of the European part of Russia) are presented. The diversity of hydrophytic vegetation has been classified into 3 classes (Lemnetea, Potametea and Phragmito-Magnocaricetea), 5 orders, 8 alliances, 20 associations and 1 community. Subassociation Scolochloetum festucaceae caricetosum aquatilis is new. Communities of associations Caricetum aquatilis, Equisetetum fluviatilis, Potamo—Nupharetum luteae, Potametum perfoliati are mostly wide distributed, while these of Phragmitetum communis, Scolochloetum festucaceae ones are relatively rare as well as Lemno—Spirodeletum polyrchizae, Elodeo—Potametum alpini, Potamo—Nupharetum pumilae, Potametum praelongi and Scirpetum lacustris are very rare. Some communities contain 2 regional rare species: Scolochloa festucacea and Ranunculus lingua.

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