Accession Number:

ADA224715

Title:

Single-Species Dominance in a Subsurface Phytoplankton Concentration at a Mediterranean Sea Front

Descriptive Note:

Journal article

Corporate Author:

NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS

Report Date:

1990-01-01

Pagination or Media Count:

12.0

Abstract:

A narrow band of high Chl a 23.1 ug liter-1 was observed at a salinity front in the western Mediterranean Sea in late November 1987. The biomass peak was found deep in the photic zone, at 54 m, in a region of low light. A single diatom species, Thalassiosira partheneia Schrader in gelationous colonies, represented 98 of the total phytoplankton biomass in the layer and achieved abundance. Although lack of temporal sampling precludes precise determination of the processes responsible, the high biomass accumulation and dominance by this species was likely due to its preference for low light coupled with turbulence-induced high nutrient levels. Interleaving patterns in the temperature, salinity, and nutrient profiles suggest increased horizontal advection at the front. High shear at the boundaries of the interleavings might confine the biomass to a thin band, as well as generate turbulence to mix nutrients in from surrounding layers. Alternatively, stabilization of the water column following a brief, pulsed upwelling event could have reduced dispersion of the biomass, thereby confining it to the thin layer we observed. Keywords Ocean environments Phytoplankton Chemical oceanography Ocean currents.

Subject Categories:

  • Biological Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE