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Single‐species dominance in a subsurface phytoplankton concentration at a Mediterranean Sea front
Author(s) -
Gould Richard W.,
Wiesenburg Denis A.
Publication year - 1990
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1990.35.1.0211
Subject(s) - oceanography , dominance (genetics) , photic zone , upwelling , salinity , mediterranean sea , nutrient , water column , phytoplankton , environmental science , biomass (ecology) , front (military) , temperature salinity diagrams , pelagic zone , advection , benthic zone , mediterranean climate , mesopelagic zone , biology , geology , ecology , biochemistry , physics , gene , thermodynamics
A narrow band of high Chl a (23.1 µ g 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 gelatinous colonies, represented 98% of the total phytoplankton biomass in the layer and achieved abundances >9.8 × 10 6 cells liter −1 . 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.