Oceans

@book{berkner1964in1,
    author = "Berkner, L. V. and Marshall, L. C",
    title = "in Brancazio, P. J., and Cameron, A. G. W., eds., The Origin and Evolution of the Atmosphere and Oceans",
    year = "1964",
    publisher = "New York, John Wiley and Sons, p. 102-126",
    note = "talkorigins\_source = {true}; raw\_reference = {Berkner, L. V., and Marshall, L. C., 1964,, in Brancazio, P. J., and Cameron, A. G. W., eds., The Origin and Evolution of the Atmosphere and Oceans: New York, John Wiley and Sons, p. 102-126.}"
}

@misc{ladd1967drilling6,
    author = "Ladd, H. S. and Gross, M. G",
    title = "Drilling on Midway Atoll, Hawaii",
    year = "1967",
    howpublished = "Science, v. 156, p. 1088-1094",
    note = "talkorigins\_source = {true}; raw\_reference = {Ladd, H. S., and Gross, M. G., 1967, Drilling on Midway Atoll, Hawaii: Science, v. 156, p. 1088-1094.}"
}

@misc{ericson1968pleistocene4,
    author = "Ericson, D. B. and Wollin, G",
    title = "Pleistocene climates and chronology in deep-sea sediments",
    year = "1968",
    howpublished = "Science, v. 162, p. 1227-1234",
    note = "talkorigins\_source = {true}; raw\_reference = {Ericson, D. B., and Wollin, G., 1968, Pleistocene climates and chronology in deep-sea sediments: Science, v. 162, p. 1227-1234.}"
}

@book{macdonald1970volcanoes8,
    author = "Macdonald, G. A. and Abbott, A. T",
    title = "Volcanoes in the Sea",
    year = "1970",
    publisher = "The Geology of Hawaii: Honolulu, Hawaii, University of Hawaii Press, 441 p",
    note = "talkorigins\_source = {true}; raw\_reference = {Macdonald, G. A., and Abbott, A. T., 1970, Volcanoes in the Sea: The Geology of Hawaii: Honolulu, Hawaii, University of Hawaii Press, 441 p.}"
}

@misc{macintyre1970why9,
    author = "MacIntyre, F",
    title = "Why the Sea is Salt",
    year = "1970",
    howpublished = "Scientific American, v. 223, no. 5",
    note = "talkorigins\_source = {true}; raw\_reference = {MacIntyre, F., 1970, Why the Sea is Salt: Scientific American, v. 223, no. 5.}"
}

@techreport{sclater1974evolution13,
    author = "Sclater, J. G. and Fisher, R. L",
    title = "Evolution of the East Indian Ocean",
    year = "1974",
    howpublished = "Geological Society of America Bulletin, v. 85, p. 683-702",
    note = "talkorigins\_source = {true}; raw\_reference = {Sclater, J. G., and Fisher, R. L., 1974, Evolution of the East Indian Ocean: Geological Society of America Bulletin, v. 85, p. 683-702.}"
}

@misc{hallam1977secular5,
    author = "Hallam, A",
    title = "Secular changes in marine inundation of USSR and North America during the Phanerozoic",
    year = "1977",
    howpublished = "Nature, v. 269, p. 769-772",
    note = "talkorigins\_source = {true}; raw\_reference = {Hallam, A., 1977, Secular changes in marine inundation of USSR and North America during the Phanerozoic: Nature, v. 269, p. 769-772.}"
}

@misc{langseth1977the7,
    author = "Langseth, M",
    title = "The seafloor and the Earth's heat engine",
    year = "1977",
    howpublished = "Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44",
    note = "talkorigins\_source = {true}; raw\_reference = {Langseth, M., 1977, The seafloor and the Earth's heat engine: Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44.}"
}

@misc{ruddieman1981oceanic12,
    author = "Ruddieman, W. F. and McIntyre, A",
    title = "Oceanic mechanisms for amplification of the 23,000-year ice-volume cycle",
    year = "1981",
    howpublished = "Science, v. 212, p. 617-627",
    note = "talkorigins\_source = {true}; raw\_reference = {Ruddieman, W. F., and McIntyre, A., 1981, Oceanic mechanisms for amplification of the 23,000-year ice-volume cycle: Science, v. 212, p. 617-627.}"
}

@misc{raup1982mass10,
    author = "Raup, D. M. and Sepkoski, J. J. and Jr",
    title = "Mass extinctions in the marine fossil record",
    year = "1982",
    howpublished = "Science, v. 215, p. 1501-1502",
    note = "talkorigins\_source = {true}; raw\_reference = {Raup, D. M., and Sepkoski, J. J., Jr., 1982, Mass extinctions in the marine fossil record: Science, v. 215, p. 1501-1502.}"
}

Mass extinctions have been fairly frequent events in the oceans during the course of Phanerozoic time. As many as 15 such events have been recognized in the marine fossil record. Global taxonomic and regional biostratigraphic data show that these mass extinctions have been variable both in severity and in taxonomic groups and geographic areas affected. The Late Permian mass extinction was by far the most severe, affecting nearly all animal groups in most parts of the world. Four other mass extinctions were of intermediate magnitude: the Ashgillian event at the end of the Ordovician, the Frasnian event in the Late Devonian, the Norian event in the Late Triassic, and the Maestrichtian event at the end of the Cretaceous. All 15 mass extinctions occurred within a timespan ranging from a fraction of a stratigraphic stage to at most two stages. Waiting times between mass extinctions were extremely variable and appear not to conform to the simple expectations of either a random or a cyclic incidence of extinction-causing perturbations.

@incollection{sepkoski1982mass,
    author = "Sepkoski, J. John",
    title = "Mass extinctions in the Phanerozoic oceans: A review",
    year = "1982",
    booktitle = "Geological Implications of Impacts of Large Asteroids and Comets on the Earth",
    abstract = "Mass extinctions have been fairly frequent events in the oceans during the course of Phanerozoic time. As many as 15 such events have been recognized in the marine fossil record. Global taxonomic and regional biostratigraphic data show that these mass extinctions have been variable both in severity and in taxonomic groups and geographic areas affected. The Late Permian mass extinction was by far the most severe, affecting nearly all animal groups in most parts of the world. Four other mass extinctions were of intermediate magnitude: the Ashgillian event at the end of the Ordovician, the Frasnian event in the Late Devonian, the Norian event in the Late Triassic, and the Maestrichtian event at the end of the Cretaceous. All 15 mass extinctions occurred within a timespan ranging from a fraction of a stratigraphic stage to at most two stages. Waiting times between mass extinctions were extremely variable and appear not to conform to the simple expectations of either a random or a cyclic incidence of extinction-causing perturbations.",
    url = "https://doi.org/10.1130/spe190-p283",
    doi = "10.1130/spe190-p283",
    pages = "283-290"
}

@misc{suess1982personal15,
    author = "Suess, H. E",
    title = "Personal communication cited as s ource of Figure 1, P. 14, in E. M. Druffel [1982] Banded corals",
    year = "1982",
    howpublished = "changes in oceanic carbon-14 during the Little Ice Age: Science, v. 218, p. 13-19",
    note = "talkorigins\_source = {true}; raw\_reference = {Suess, H. E., 1982, Personal communication cited as s ource of Figure 1, P. 14, in E. M. Druffel [1982] Banded corals: changes in oceanic carbon-14 during the Little Ice Age: Science, v. 218, p. 13-19.}"
}

@misc{edmond1983hot3,
    author = "Edmond, J. M. and Von Damm, K",
    title = "Hot springs on the ocean floor",
    year = "1983",
    howpublished = "Scientific American, v. 248, no. 4, p. 78-93",
    note = "talkorigins\_source = {true}; raw\_reference = {Edmond, J. M., and Von Damm, K., 1983, Hot springs on the ocean floor: Scientific American, v. 248, no. 4, p. 78-93.}"
}

@article{brooks1984the2,
    author = "Brooks, W. K",
    title = "The origin of the oldest fossils and the discovey of the bottom of the ocean",
    year = "1984",
    journal = "Journal of Geology, v. 2, p. 455-479",
    note = "talkorigins\_source = {true}; raw\_reference = {Brooks, W. K., 1984, The origin of the oldest fossils and the discovey of the bottom of the ocean: Journal of Geology, v. 2, p. 455-479.}"
}

@techreport{ruddieman1984iceage11,
    author = "Ruddieman, W. F",
    title = "Ice-age thermal and climatic role of the surface Atlantic Ocean, 40 degrees N to 63 degrees N",
    year = "1984",
    howpublished = "Geological Society of America Bulletin, v. 95, p. 381-396",
    note = "talkorigins\_source = {true}; raw\_reference = {Ruddieman, W. F., 1984, Ice-age thermal and climatic role of the surface Atlantic Ocean, 40 degrees N to 63 degrees N: Geological Society of America Bulletin, v. 95, p. 381-396.}"
}

@misc{stanley1984mass14,
    author = "Stanley, S. M",
    title = "Mass extinctions in the oceans",
    year = "1984",
    howpublished = "Scientific American, v. 250, no. 6, p. 64-72",
    note = "talkorigins\_source = {true}; raw\_reference = {Stanley, S. M., 1984, Mass extinctions in the oceans: Scientific American, v. 250, no. 6, p. 64-72.}"
}

@misc{weisburd1987sea16,
    author = "Weisburd, S",
    title = "Sea cycle clock",
    year = "1987",
    howpublished = "Science News, v. 131, p. 154-155",
    note = "talkorigins\_source = {true}; raw\_reference = {Weisburd, S., 1987, Sea cycle clock: Science News, v. 131, p. 154-155.}"
}

Understanding ancient oceanic conditions becomes fundamentally easier in the Cretaceous due to the plentiful oceanic crust of this age. Coincidentally, the proliferation and radiation of planktonic foraminifera in the Early Cretaceous also allow the direct study of fluctuations in oceanic surface waters for the first time. With this burgeoning of the data base, all post-Jurassic extinction mechanisms have to be in accord with both open-ocean and shelf-sea evidence.

@incollection{hallam1997minor,
    author = "Hallam, A and Wignall, P B",
    title = "Minor mass extinctions of the marine Cretaceous",
    year = "1997",
    booktitle = "Mass Extinctions and Their Aftermath",
    abstract = "Understanding ancient oceanic conditions becomes fundamentally easier in the Cretaceous due to the plentiful oceanic crust of this age. Coincidentally, the proliferation and radiation of planktonic foraminifera in the Early Cretaceous also allow the direct study of fluctuations in oceanic surface waters for the first time. With this burgeoning of the data base, all post-Jurassic extinction mechanisms have to be in accord with both open-ocean and shelf-sea evidence.",
    url = "https://doi.org/10.1093/oso/9780198549178.003.0008",
    doi = "10.1093/oso/9780198549178.003.0008",
    pages = "170-183"
}

The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian-Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth's history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness.

@article{doi101073pnas1503755112,
    author = "Schobben, Martin and Stebbins, Alan and Ghaderi, Abbas and Strauss, Harald and Korn, Dieter and Korte, Christoph",
    title = "Flourishing ocean drives the end-Permian marine mass extinction.",
    year = "2015",
    journal = "Proceedings of the National Academy of Sciences of the United States of America",
    abstract = "The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian-Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth's history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC4547295/",
    doi = "10.1073/pnas.1503755112",
    pmcid = "PMC4547295",
    pmid = "26240323"
}

In post-Cambrian time, life on Earth experienced 5 major extinction events, likely instigated by adverse environmental conditions. Biodiversity loss among marine taxa, for at least 3 of these mass extinction events (Late Devonian, end-Permian and end-Triassic), has been connected with widespread oxygen-depleted and sulfide-bearing marine water. Furthermore, geochemical and sedimentary evidence suggest that these events correlate with rather abrupt climate warming and possibly increased terrestrial weathering. This suggests that biodiversity loss may be triggered by mechanisms intrinsic to the Earth system, notably, the biogeochemical sulfur and carbon cycle. This climate warming feedback produces large-scale eutrophication on the continental shelf, which, in turn, expands oxygen minimum zones by increased respiration, which can turn to a sulfidic state by increased microbial-sulfate reduction due to increased availability of organic matter. A plankton community turnover from a high-diversity eukaryote to high-biomass bacterial dominated food web is the catalyst proposed in this anoxia-extinction scenario and stands in stark contrast to the postulated productivity collapse suggested for the end-Cretaceous mass extinction. This cascade of events is relevant for the future ocean under predicted greenhouse driven climate change. The exacerbation of anoxic "dead" zones is already progressing in modern oceanic environments, and this is likely to increase due to climate induced continental weathering and resulting eutrophication of the oceans.

@article{doi1010801942088920151115162,
    author = "Schobben, Martin and Stebbins, Alan and Ghaderi, Abbas and Strauss, Harald and Korn, Dieter and Korte, Christoph",
    title = "Eutrophication, microbial-sulfate reduction and mass extinctions.",
    year = "2016",
    journal = "Communicative \& integrative biology",
    abstract = {In post-Cambrian time, life on Earth experienced 5 major extinction events, likely instigated by adverse environmental conditions. Biodiversity loss among marine taxa, for at least 3 of these mass extinction events (Late Devonian, end-Permian and end-Triassic), has been connected with widespread oxygen-depleted and sulfide-bearing marine water. Furthermore, geochemical and sedimentary evidence suggest that these events correlate with rather abrupt climate warming and possibly increased terrestrial weathering. This suggests that biodiversity loss may be triggered by mechanisms intrinsic to the Earth system, notably, the biogeochemical sulfur and carbon cycle. This climate warming feedback produces large-scale eutrophication on the continental shelf, which, in turn, expands oxygen minimum zones by increased respiration, which can turn to a sulfidic state by increased microbial-sulfate reduction due to increased availability of organic matter. A plankton community turnover from a high-diversity eukaryote to high-biomass bacterial dominated food web is the catalyst proposed in this anoxia-extinction scenario and stands in stark contrast to the postulated productivity collapse suggested for the end-Cretaceous mass extinction. This cascade of events is relevant for the future ocean under predicted greenhouse driven climate change. The exacerbation of anoxic "dead" zones is already progressing in modern oceanic environments, and this is likely to increase due to climate induced continental weathering and resulting eutrophication of the oceans.},
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC4802792/",
    doi = "10.1080/19420889.2015.1115162",
    pmcid = "PMC4802792",
    pmid = "27066181"
}

The Central Atlantic magmatic province (CAMP), the end-Triassic mass extinction (ETE), and associated major carbon cycle perturbations occurred synchronously around the Triassic-Jurassic (T-J) boundary (201 Ma). Negative carbon isotope excursions (CIEs) recorded in marine and terrestrial sediments attest to the input of isotopically light carbon, although the carbon sources remain debated. Here, we explore the effects of mantle-derived and thermogenic carbon released from the emplacement of CAMP using the long-term ocean-atmosphere-sediment carbon cycle reservoir (LOSCAR) model. We have tested a detailed emission scenario grounded by numerous complementary boundary conditions, aiming to model the full extent of the carbon cycle perturbations around the T-J boundary. These include three negative CIEs (i.e., Marshi/Precursor, Spelae/Initial, Tilmanni/Main) with sharp positive CIEs in between. We show that a total of ∼24,000 Gt C (including ∼12,000 Gt thermogenic C) replicates the proxy data. These results indicate that thermogenic carbon generated from the contact aureoles around CAMP sills represents a credible source for the negative CIEs. An extremely isotopically depleted carbon source, such as marine methane clathrates, is therefore not required. Furthermore, we also find that significant organic carbon burial, in addition to silicate weathering, is necessary to account for the positive δ13C intervals following the negative CIEs.

@article{doi101073pnas2000095117,
    author = "Heimdal, Thea H and Jones, Morgan T and Svensen, Henrik H",
    title = "Thermogenic carbon release from the Central Atlantic magmatic province caused major end-Triassic carbon cycle perturbations.",
    year = "2020",
    journal = "Proceedings of the National Academy of Sciences of the United States of America",
    abstract = "The Central Atlantic magmatic province (CAMP), the end-Triassic mass extinction (ETE), and associated major carbon cycle perturbations occurred synchronously around the Triassic-Jurassic (T-J) boundary (201 Ma). Negative carbon isotope excursions (CIEs) recorded in marine and terrestrial sediments attest to the input of isotopically light carbon, although the carbon sources remain debated. Here, we explore the effects of mantle-derived and thermogenic carbon released from the emplacement of CAMP using the long-term ocean-atmosphere-sediment carbon cycle reservoir (LOSCAR) model. We have tested a detailed emission scenario grounded by numerous complementary boundary conditions, aiming to model the full extent of the carbon cycle perturbations around the T-J boundary. These include three negative CIEs (i.e., Marshi/Precursor, Spelae/Initial, Tilmanni/Main) with sharp positive CIEs in between. We show that a total of ∼24,000 Gt C (including ∼12,000 Gt thermogenic C) replicates the proxy data. These results indicate that thermogenic carbon generated from the contact aureoles around CAMP sills represents a credible source for the negative CIEs. An extremely isotopically depleted carbon source, such as marine methane clathrates, is therefore not required. Furthermore, we also find that significant organic carbon burial, in addition to silicate weathering, is necessary to account for the positive δ13C intervals following the negative CIEs.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC7275695/",
    doi = "10.1073/pnas.2000095117",
    pmcid = "PMC7275695",
    pmid = "32424084"
}

Over geologic time, biocalcification - the process by which marine organisms make calcium carbonate (CaCO3) - has reshaped climates, ocean life, and seawater chemistry. In particular, the evolution of coccolithophores, the largest group of nannoplankton and today's most productive calcifiers, transformed ocean environments and the carbon cycle. Their origins, however, remain enigmatic. This is partly because studying coccolithophore fossils traditionally requires CaCO3 preservation. Here, we bypass this limitation, searching for their 'ghost' fossils -imprints on organic matter. We present coccolithophores from ~241-million-year-old (Triassic) rocks, predating previous records by ~26 million years (myrs). The >100 ghost fossils, exceptionally preserved within zooplankton faeces, show that coccolithophores, nannoplankton, 'modern' eukaryotic phytoplankton, and planktonic biocalcification evolved earlier than previously thought. Coccolithophores now first appear alongside stony corals and other unrelated calcifiers, suggesting a diversification of a range of marine calcifying organisms following Earth's deadliest mass extinction, the end-Permian event. These findings indicate that coccolithophore diversity remained remarkably low for ~50 myrs, until after the end-Triassic mass extinction, showing that both Triassic-bookending extinctions were critical in their evolution. Our discoveries elucidate the evolutionary origins of coccolithophores, but also highlight the role mass extinctions have played in shaping life on Earth.

@article{doi101038s41467025651160,
    author = "Slater, Sam M and Demangel, Isaline and Richoz, Sylvain",
    title = "'Ghost' fossils of early coccolithophores point to a Triassic diversification of marine calcifying organisms.",
    year = "2025",
    journal = "Nature communications",
    abstract = "Over geologic time, biocalcification - the process by which marine organisms make calcium carbonate (CaCO3) - has reshaped climates, ocean life, and seawater chemistry. In particular, the evolution of coccolithophores, the largest group of nannoplankton and today's most productive calcifiers, transformed ocean environments and the carbon cycle. Their origins, however, remain enigmatic. This is partly because studying coccolithophore fossils traditionally requires CaCO3 preservation. Here, we bypass this limitation, searching for their 'ghost' fossils -imprints on organic matter. We present coccolithophores from \textasciitilde 241-million-year-old (Triassic) rocks, predating previous records by \textasciitilde 26 million years (myrs). The >100 ghost fossils, exceptionally preserved within zooplankton faeces, show that coccolithophores, nannoplankton, 'modern' eukaryotic phytoplankton, and planktonic biocalcification evolved earlier than previously thought. Coccolithophores now first appear alongside stony corals and other unrelated calcifiers, suggesting a diversification of a range of marine calcifying organisms following Earth's deadliest mass extinction, the end-Permian event. These findings indicate that coccolithophore diversity remained remarkably low for \textasciitilde 50 myrs, until after the end-Triassic mass extinction, showing that both Triassic-bookending extinctions were critical in their evolution. Our discoveries elucidate the evolutionary origins of coccolithophores, but also highlight the role mass extinctions have played in shaping life on Earth.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC12537907/",
    doi = "10.1038/s41467-025-65116-0",
    pmcid = "PMC12537907",
    pmid = "41115954"
}

During the end-Permian mass extinction, a global decline in seafloor sediment mixing and burrowing (bioturbation) provides critical evidence for the collapse of marine ecosystems, likely triggered by rapid ocean warming and deoxygenation. However, the decline and subsequent recovery of bioturbation after the extinction event may not only have been a symptom of environmental change but also a driver, influencing nutrient exchange and reductant burial across the sediment-water interface and thus water column oxygen availability and seafloor habitability more broadly. Here we test this hypothesis through combined analyses of bioturbation and sedimentary geochemistry, focusing on marine siliciclastic records of the Permian-Triassic transition from Svalbard. We find that total organic carbon, total sulfur, and organic phosphorus decrease with increasing bioturbation intensity, whereas inorganic reactive phosphorus phases (authigenic and iron oxide-bound phosphorus) increase. These differences are most strongly associated with biodiffusion (particle mixing) rather than bioirrigation (solute exchange). Our findings suggest that bioturbation primarily influenced sediment chemistry by enhancing organic matter oxidation, in contrast to some modern settings where downward mixing may promote organic matter preservation within the anoxic portion of seafloor sediments. The early return of shallow-tier bioturbators in this region 1 Myr after the mass extinction.

@article{doi101111gbi70032,
    author = "Beaty, Brian and Foster, William J and Zuchuat, Valentin and Moller, Spencer R and Buchwald, Stella Z and Brooks, Hannah and Rauzi, Sofia and Isson, Terry and Planke, Sverre and Rodríguez-Tovar, Francisco J and Senger, Kim and Planavsky, Noah and Tarhan, Lidya",
    title = "Bioturbation Shapes Marine Biogeochemical Cycling Following the End-Permian Mass Extinction in Northern Pangea.",
    year = "2025",
    journal = "Geobiology",
    abstract = "During the end-Permian mass extinction, a global decline in seafloor sediment mixing and burrowing (bioturbation) provides critical evidence for the collapse of marine ecosystems, likely triggered by rapid ocean warming and deoxygenation. However, the decline and subsequent recovery of bioturbation after the extinction event may not only have been a symptom of environmental change but also a driver, influencing nutrient exchange and reductant burial across the sediment-water interface and thus water column oxygen availability and seafloor habitability more broadly. Here we test this hypothesis through combined analyses of bioturbation and sedimentary geochemistry, focusing on marine siliciclastic records of the Permian-Triassic transition from Svalbard. We find that total organic carbon, total sulfur, and organic phosphorus decrease with increasing bioturbation intensity, whereas inorganic reactive phosphorus phases (authigenic and iron oxide-bound phosphorus) increase. These differences are most strongly associated with biodiffusion (particle mixing) rather than bioirrigation (solute exchange). Our findings suggest that bioturbation primarily influenced sediment chemistry by enhancing organic matter oxidation, in contrast to some modern settings where downward mixing may promote organic matter preservation within the anoxic portion of seafloor sediments. The early return of shallow-tier bioturbators in this region 1 Myr after the mass extinction.",
    url = "https://pubmed.ncbi.nlm.nih.gov/40968765/",
    doi = "10.1111/gbi.70032",
    pmid = "40968765"
}