Benthos-Pelagos Interconnectivity: Antarctic Shelf Examples

Abstract

This review focuses on studies dealing with the coupling between the benthic and pelagic realms on Antarctic shelves and on factors that regulate these processes. Such studies in Antarctic waters are scarce, especially on the shelves, where flux studies via moorings are highly endangered by drifting icebergs. Nevertheless, such studies are essential to understand these processes and functioning of the cold water ecosystem and how energy is transported through its different compartments. Different abiotic (e.g., currents, sea ice, water depth, topography of the seafloor, seasonality) and biotic (e.g., composition and structure of the benthic and pelagic flora and fauna, primary production, vertical migrations) factors are presented as parameters regulating the coupling between benthos and pelagos, here defined as benthos-pelagos interconnectivity. Regional variability in these parameters may result in delayed or even different coupling and/or decoupling of these realms. This is exemplarily discussed comparing the West Antarctic Peninsula (WAP) and Eastern Weddell Sea Shelf (EWSS). While in the WAP both compartments appear decoupled, on the EWSS both compartments appear tightly connected. The development of the benthos in the Larsen embayments after the shelf ice disintegration is described as an example of how changes in the pelagic realm affect and modify also the benthic realm.

Trophic structuring of modularity alters energy flow through marine food webs

“…The Antarctic Circumpolar Current also provides these Southern Ocean ecosystems with relatively stable and predictable oceanographic conditions (Murphy et al, 2007;Morley et al, 2020), which might help to drive the similarity in modular organisation. Both ecosystems experience a high degree of connectivity, with large-scale diurnal vertical migrations in the Scotia Sea and strong bentho-pelagic coupling in the Weddell Sea (Piatkowski et al, 1994;La Mesa et al, 2019;Pineda-Metz, 2020). This may result in a stronger interdependence between modules in both ecosystems, as the deeper top-predator modules rely on the energy generated in the near-surface basal resource modules, linked via the diurnal migrators or bentho-pelagic couplers.…”