Chapter 5 Feeding and Food Processing in Antarctic Krill (Euphausia superba Dana)

Schmidt, K; Atkinson, A. 2016 Chapter 5 Feeding and Food Processing in Antarctic Krill (Euphausia superba Dana). In: Siegel, V, (ed.) Biology and Ecology of Antarctic krill. Switzerland, Springer, 175-224, 441pp. (Advances in Polar Ecology).

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Official URL: http://www.springer.com/series/10290

Abstract/Summary

Euphausia superba is exceptional among euphausiids for the large filtering surface of the feeding basket and its fine mesh size (2–3 μm), which remain into adulthood. This enables them to feed efficiently on nano- and microplankton, and to reach substantial growth rates with food concentrations as low as 0.5 μg Chlorophyll a L �1. Even though phytoplankton – in particular diatoms – are their staple food, protozoans and small copepods are ingested simultaneously and represent an important supplementary food source year-round. However, krill feeding behaviour is more complex than just filter-feeding in the water column, it includes raptorial capture of larger zooplankton, handling of ‘giant’ diatoms, scraping algae from beneath sea ice and lifting detritus from the seabed. High mobility and physiological robustness enable krill to explore three feeding grounds – the water column, the sea ice and the benthos. Variability in access and productivity of these feeding grounds leads to fundamental differences in krill overwintering across their habitats. Gut passage time, absorption efficiency and fecal pellet density vary with food concentration and nutritional needs. Therefore krill fecal pellets have a dual role; some promote the export of carbon and nutrients while others facilitate the recycling of material in the upper water column. Krill grazing can suppress phytoplankton blooms, but this tends to be a localised phenomenon where krill abundances are exceptionally high. Conversely, krill appear to have major conditioning effects due to nutrient supply (e.g. ammonium, iron), although their role in Southern Ocean biogeochemical cycles is only starting to be discovered.

Item Type: Publication - Book Section
Additional Keywords: krill feeding Antarctica Southern Ocean diet Euphausia superba
Subjects: Ecology and Environment
Marine Sciences
Oceanography
Divisions: Plymouth Marine Laboratory > Science Areas > Marine Ecology and Biodiversity
Depositing User: Angus Atkinson
Date made live: 26 Apr 2018 14:01
Last Modified: 17 Dec 2018 15:55
URI: http://plymsea.ac.uk/id/eprint/7776

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