Pelagic Habitat

Productivity in oceanic settings depends on light and nutrient availability, while overall production is the result of productivity and accumulation of the phytoplankton. The mechanism involved to generate the productivity at a seamount are related to its shallowness that allows the vertical flux of nutrient to reach the euphotic zone and the resultant productivity be retained long enough over the seamount to allow the transference of energy to higher trophic levels, or the seamount must rely on allochthonous inputs of organic material to provide a trophic subsidy to resident populations. A classical view of the biophysical coupling leading to enhanced primary productivity is the upwelling of nutrients associated with the presence of a Taylor column over a shallow seamount, which result in a steady flow over it, creating both an anticyclonic flow and an isopycnal doming, and bringing nutrient rich waters to the upper layers of the water column. Biophysical coupling, therefore, can have a profound effect on the production at seamounts. At the same time, localized dynamic responses may also promote productivity through retention processes. Inherent variability in the dynamic forcing, particularly at shallow seamounts, can prevent plankton accumulation and contribute to mesoscale variability in the surrounding ocean. Three energetic processes have been proposed to support the large biomass of seamount consumers: phytoplankton production, which is the classical view that enhanced primary production on seamounts fuels higher-order predators through a bottom-up mechanism; topographic trapping that advocates that summits and flanks of seamounts can block the descent of vertically migrating zooplankton, which are preyed by higher trophic levels; and trophic subsidy occurring when flow regimes interacting with a seamount amplify the horizontal food supply to seamount communities. With the attempt of address the biodiversity in the Madeira-Tore and Great Meteor seamounts, this WP will include different approaches for the pelagic community assessment of biodiversity, dominated in terms of abundance and biomass by planktonic and nektonic communities, as well as the associated oceanographic processes.

  • promotor
  • partners
  • colaboradores
  • financiamento