Does the Phaeocystis bloom affect the diel migration of the suprabenthos community?
In: Marine Pollution Bulletin. Macmillan: London. ISSN 0025-326X; e-ISSN 1879-3363, more
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| Keywords |
Abundance
Algal blooms
Aquatic communities > Benthos
Aquatic communities > Plankton > Phytoplankton
Behaviour > Migrations > Vertical migrations
Biodiversity
Coastal zone
Eutrophication
Fauna > Aquatic organisms > Aquatic animals > Fish
Interspecific relationships > Predation
Layers > Boundary layers
Layers > Boundary layers > Benthic boundary layer
Layers > Water column
Light intensity
Locomotion > Swimming
Physics > Mechanics > Fluid mechanics > Hydrodynamics
Population characteristics > Population density
Seawater
Species diversity
Animalia [WoRMS]; Crustacea [WoRMS]; Cumacea [WoRMS]; Mysida [WoRMS]; Peracarida [WoRMS]; Phaeocystis Lagerheim, 1893 [WoRMS]
Marine/Coastal |
| Author keywords |
suprabenthos; English channel; Phaeocystis bloom; diel migration |
| Authors | | Top |
- Dauvin, J.-C., more
- Desroy, N.
- Denis, L., more
- Ruellet, T.
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| Abstract |
The suprabenthos comprises all bottom-dependent animals, mainly crustaceans (including decapods and peracarids), which perform - with varying amplitude, intensity and regularity - seasonal or daily vertical migrations above the sea floor. The presence of organisms in the Benthic Boundary Layer is determined by two general factors: (1) organism behaviour, which depends on the light penetration in the water column and (2) boundary-layer hydrodynamics. In the coastal zone of the eastern English Channel, during the spring Phaeocystis bloom, the presence of gelatinous colonies modifies the penetration of light in the water column, which may seriously affect the abundance and/or the behaviour of the suprabenthos community. To clarify this point, 19 suprabenthic hauls were taken with a modified Macer-GIROQ sledge both during the day and during the night, from March to June 2002 (i.e., before, during and after the bloom). Two sites, located in the coastal and offshore areas of the Ophelia medium sand macrobenthic community were investigated. The bloom had no effect on species richness and abundance in either site. However, the diel migrations of some dominant species - such as the cumaceans Pseudocuma longicornis and Pseudocuma similis, the mysid Gastrosaccus spinifer and the amphipod Stenothoe marina - were modified. During the bloom, diurnal and nocturnal suprabenthic abundances were similar, and in the absence of bloom, species remained benthic during the day. The permanent presence of suprabenthic species in the Benthic Boundary Layer could have a consequence on their predation by fish (mainly juveniles which preferentially consume small crustaceans in their diet), unless fish behaviour and predation efficiency - especially for visual predators - are also disturbed by changes in light intensity. |
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