Time-Based Correlation of Biogenic, Lithogenic and Authigenic Sediment Components with Anthropogenic Inputs in the Gulf of Mexico NECOP Study Area

Authors

Terry A. Nelsen, National Oceanic and Atmospheric Administration
Patricia Blackwelder, University of MiamiFollow
Terri Hood, University of Miami
Brent McKee, Louisiana Universities Marine Consortium
Nidia Romer, University of Miami
Carlos A. Alvarez Zarikian, University of Miami
Simone Metz, Florida Institute of Technology

Document Type

Article

Publication Title

Estuaries and Coasts

ISSN

1559-2723

Publication Date

12-1-1994

Abstract

Hypotheses related to variability in seasonal hypoxic conditions, coastal nutrient enhancement, and off-shelf transport of carbon on the Louisiana continental shelf were tested by characterization of biogenic, lithogenic, and authigenic components from two shelf and one Mississippi Canyon sediment cores. The authigenic-phase glauconite occurs above detection limits only in the core from the hypoxic area. A major increase in glauconite concentration was coincident with the onset (≈1940) of the increased use of commercial fertilizers in the United States. In the same hypoxic-area core, benthic foraminifera species diversity decreases upcore from approximately the turn of the century to the present in a manner concurrent with glauconite and fertilizer increases. A subset of opportunistic benthic foraminifera species, known to become more prominent in stressed environments (i.e., hypoxic), increased upcore from ∼52% of the total population at core bottom to ≈90% at core top. These benthic foraminifera population and diversity changes were not apparent in a “control” core outside the area of documented hypoxia. Seaward of the shelf, in the Mississippi Canyon, coincident increases in sediment accumulation rate, percentages of coarse fraction and of organic carbon at core top indicate increased offshelf transport of carbon and other components. Quartz percentages indicate that episodic down-canyon transport has been active to core bottom (prior to the mid 1800s).

DOI

10.2307/1352755

Volume

17

Issue

4

First Page

873

Last Page

885

Comments

©1994 Estuarine Research Federation

NSUWorks Citation

Terry A. Nelsen, Patricia Blackwelder, Terri Hood, Brent McKee, Nidia Romer, Carlos A. Alvarez Zarikian, and Simone Metz. 1994. Time-Based Correlation of Biogenic, Lithogenic and Authigenic Sediment Components with Anthropogenic Inputs in the Gulf of Mexico NECOP Study Area .Estuaries and Coasts , (4) : 873 -885. https://nsuworks.nova.edu/occ_facarticles/437.