Skip to main content
Article
Time-Based Correlation of Biogenic, Lithogenic and Authigenic Sediment Components with Anthropogenic Inputs in the Gulf of Mexico NECOP Study Area
Estuaries and Coasts
  • Terry A. Nelsen, National Oceanic and Atmospheric Administration
  • Patricia Blackwelder, University of Miami
  • 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 Date
12-1-1994
Peer Reviewed
1
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).
Comments

©1994 Estuarine Research Federation

DOI
10.2307/1352755
Citation Information
Terry A. Nelsen, Patricia Blackwelder, Terri Hood, Brent McKee, et al.. "Time-Based Correlation of Biogenic, Lithogenic and Authigenic Sediment Components with Anthropogenic Inputs in the Gulf of Mexico NECOP Study Area" Estuaries and Coasts Vol. 17 Iss. 4 (1994) p. 873 - 885 ISSN: 1559-2723
Available at: http://works.bepress.com/patricia-blackwelder/32/