Here we go!!

Cruise LMG11-10 will support Palmer Station, the seasonal opening of the Cape Shirreff marine mammal research facility plus the two NSF-funded primary research projects described below. These two projects operate in close collaboration, and the term “salp survey” is used in reference to both collectively. Dr. Ann Bucklin, the PI for project B-285-L, has been designated as Chief Scientist for the cruise. This means that in addition to her own research project, Dr. Bucklin has the added responsibility of ensuring that all other projects on the cruise are given appropriate support.

Science Overview

Population Ecology of Salpa thompsoni based on Molecular Indicators. PI: Dr. Ann Bucklin, University of Connecticut

Science objectives:The overall objectives of this effort are to examine genome-wide patterns of gene expression, target gene expression levels, and patterns of population genetic diversity and structure of the Antarctic salp, Salpa thompsoni in relation to biological and physical environmental parameters in the Western Antarctic Peninsula region.

Major activities: Four people will deploy for this project. High-frequency acoustics data will be used to provide information about the distribution of salps, krill, and other zooplankton. Sampling from shelf and oceanic waters between 0 and 2,000 meters will take place at selected stations using a 1-m² MOCNESS to characterize the planktonic assemblage and a Reeve net to collect live material for molecular and biochemical analysis. Environmental parameters to be measured include standard hydrographic variables (temperature, salinity, depth), as well as fluorescence and turbidity. Water samples will be collected using a CTD rosette to determine chlorophyll concentration

The Vacuum cleaners of the Ocean

You are probably wondering what kind of creatures salps are and what they look like. Well, they are almost like vacuum cleaners of the ocean. In general they are like a cylinder with muscle bands contracting along their body with a size of a few centimeters. The contraction provides a pulse of water through their body, producing a jet propulsion for the salp, which is a similar principle found in squid.

The distribution of these muscle bands is very useful to identify different salp species. Each species consist of two forms; the solitary and the aggregate. The solitary form as the name indicates lives on its own (upper picture), whereas aggregate forms lives in chains consisting of 100–150 members (lower picture). They can form large swarms consisting of thousands of individuals.

Salps and krill

Previous studies have suggested that salps and krill have a tight relationship, since they consume similar food organisms and represent potential competitors for plankton. However, salps tolerate higher temperatures than krill. In the winter, when the sea ice is formed, the krill in Antarctica eats algae growing underneath it. The sea ice will decrease if temperatures of the Southern Ocean continue to increase. Consequently, the ice algae, a valuable food resource for the krill particularly in winter, will be less abundant and affect krill survival. Since salps are able to survive at higher temperatures than the Antarctic krill, the salps may then favour a warmer climate and gradually dominate over krill as a major species in the Southern Ocean.

(Text by Ann Bucklin and Paola Batta Lona, UConn; Pictures by Larry Madin, WHOI)