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CSIRO Marine and Atmospheric Research
Past Seminars

Seminar Abstract

Salp swarms: biological opportunists and ecological impacts

Several species of the genus Salpa are known for their ability to form high densities over large areas.

Recent evidence has indicated an appreciable increase in salps in the Southern Ocean during the past decades co-incident with a decline in krill, linked with reduced winter ice cover. Ecological consequences of this change are potentially considerable. Biological adaptations, including a watery composition, relatively large size at birth, the ability to feed on a wide range of particle sizes, and potential for rapid somatic and reproductive growth, all contribute to allow salps to exploit favourable nutritional conditions.

Our studies of energetics of S. aspera in the North Atlantic include investigations of metabolism, feeding, growth, reproduction and defecation. The results of this work indicate that S. aspera has the potential to increase its population density from scarce (1 salp/km2) to swarm (1 salp/m2) in a period of about three months. The resulting salp swarms can have a large ecological impact, both in terms of removal of small particulates from the epipelagic and the transport of organic material to the benthos via large fast-sinking fecal pellets.

Ongoing studies of S. thompsoni in the Southern Ocean are investigating similar processes, attempting to quantify rates important to the ecological energetics and population dynamics of this swarm-forming species.

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CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
Peter Oke, (Oceanographic seminars) CSIRO Marine Research (03) 6232 5387
Piers Dunstan, (Biological seminars) CSIRO Marine Research (03) 6232 5382
Katrina Nitschke, Antarctic Climate and Ecosystems CRC (03) 6226 2265 & IASOS, University of Tasmania (03) 6226 2509