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Census of seafloor sediments in the world's ocean

Adriana Dutkiewicz, R. Dietmar Mueller, Simon O'Callaghan and Hjortur Jonasson
Census of seafloor sediments in the world's ocean
Geology (Boulder) (August 2015) 43 (9): 795-798

Abstract

Knowing the patterns of distribution of sediments in the global ocean is critical for understanding biogeochemical cycles and how deep-sea deposits respond to environmental change at the sea surface. We present the first digital map of seafloor lithologies based on descriptions of nearly 14,500 samples from original cruise reports, interpolated using a support vector machine algorithm. We show that sediment distribution is more complex, with significant deviations from earlier hand-drawn maps, and that major lithologies occur in drastically different proportions globally. By coupling our digital map to oceanographic data sets, we find that the global occurrence of biogenic oozes is strongly linked to specific ranges in sea-surface parameters. In particular, by using recent computations of diatom distributions from pigment-calibrated chlorophyll-a satellite data, we show that, contrary to a widely held view, diatom oozes are not a reliable proxy for surface productivity. Their global accumulation is instead strongly dependent on low surface temperature (0.9-5.7 degrees C) and salinity (33.8-34.0 PSS, Practical Salinity Scale 1978) and high concentrations of nutrients. Under these conditions, diatom oozes will accumulate on the seafloor regardless of surface productivity as long as there is limited competition from biogenous and detrital components, and diatom frustules are not significantly dissolved prior to preservation. Quantifying the link between the seafloor and the sea surface through the use of large digital data sets will ultimately lead to more robust reconstructions and predictions of climate change and its impact on the ocean environment.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 43
Serial Issue: 9
Title: Census of seafloor sediments in the world's ocean
Affiliation: University of Sydney, School of Geosciences, EarthByte Group, Sydney, N.S.W., Australia
Pages: 795-798
Published: 20150805
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 30
Accession Number: 2015-087064
Categories: Oceanography
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2015271
Illustration Description: geol. sketch maps
Secondary Affiliation: National ICT Australia, AUS, Australia
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201537
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