Photo: Sea cucumber: Brigitte Ebbe

SYSTCO stands for system coupling, meaning mutual influences of atmosphere, water and deep-sea floor. To investigate these processes, about 50 scientists got together in Cape Town in November 2007 to participate in an unusual expedition which was to last until February 2008. The expedition was so special because part of the scientific party was going to work in the water column and the other on the seafloor. The aim of the expedition SYSTCO was to find a plankton bloom, follow its track and, after the cells had died off, document the fate of the so-called marine snow until its arrival on the deep-sea floor in 4500 m depth, and find out how the benthic communities reacted to this nutrient pulse. Marine snow is the only source of energy for the abyssal benthos (with the exception of chemosynthetic environments such as hydrothermal vents.) This can mean that global climate change has especially direct effects on the deep-sea floor.

In spite of bad weather and substantial loss of time due to difficult logistics, the expedition was successful in the end. The fact that we could prove that, with everybody determined to cooperate, it is very well possible for plankton and benthos specialists to work on the same deck was not the least part of this success story. It was an inspiring experience for everybody!

The region covered by Polarstern during this expedition extended from 40 to 70 degrees south, i.e. from the subtropical convergence to the Antarctic continent. To address oceanographic questions, SYSTCO I cooperated with SCACE, focused on physical, chemical and biological oceanography in the pelagic realm. One of the central tasks of the SCACE programme was to collect a unique data set that can serve as a benchmark for future comparison with existing data to identify and quantify polar changes.

As the ocean surface layer and its link to sea ice are of critical importance to the Antarctic food webs, underice fauna was scraped off with an especially constructed heavy-framed but floating net that can 'roll' along the undersurface of the sea-ice, the SUIT (Surface and Under-Ice Trawl). Zooplankton abundance was studied with a wide variety of methods, and the internazional project LAKRIS cooperated with SYSTCO as well to investigate life cycle, distribution and physiology of krill in the Lazarev Sea. One of the primary questions of interest is the krill’s ability to adapt to potential environmental changes.

Some interesting results of SYSTCO are:

• The seafloor underneath the South Polar Front at 52°S is characterised by low diversity and abundance in the macrofauna, even after a slight plankton bloom in spring (revisit of stations after 7 weeks)
• The deep Eastern Weddell Sea and Lazarev Sea are generally poor in species and abundance of organisms
• The seamount Maud Rise differs completely in taxon composition from the abyssal stations, perhaps due to unique physical oceanographic conditions which may keep larvae from leaving the seamount. Brooders, on the contrary, occur only as a minor fraction in the macrobenthic sample.
• The rare monoplacophoran Laevipilina antarctica was collected close to the Neumayer station (northern pier)
• A very large sea cucumber, about 70 cm long and weighing 3.6 kg indicates that these mud-feeding animals have much organic matter available
• Finding symbioses: parasitic gastropods on holothurians and crinoids, many parasitic copepods on a scale worm and on fishes
• More than ten specimens of the very rare deep-sea isopod family Haplomunnidae were collected at Maud Rise

Highlights of methods used

• Experiments on board to uncover the microbial carbon contribution to the diet of Nematoda
• Biochemical methods for food-web analysis (fatty acids and stable isotopes)
• DNA barcoding of isopods
• Further DNA extractions from isopods, polychaetes and other taxa for population genetics and phylogenetic analyses
• Five deployments of free-falling Lander equipped with in situ microprofiler for high resolution pore water oxygen profiles


For more information, please see the ANDEEP-SYSTCO Science Plan

Photo: Offloading: Brigitte Ebbe

Photo: Researchers admiring the Shelfice: Brigitte Ebbe