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Science Mission Task 4.1 Sustained observations of abyssal benthic megafauna for monitoring global change 

The deep seabed is linked intimately to processes in the upper water column by the downward flux of organic matter. Benthic communities integrate processes over space and time, and so large-scale faunal changes on the deep-sea floor reflect major processes occurring in the overlying water column (Billett et al. 2001; Ruhl & Smith, 2004). Strong coupling between surface primary production and the seafloor (Lampitt et al. 2001) profoundly influences deep-sea communities (Billett et al. 2001; Gooday 2002) and carbon recycling (Bett et al 2001). Specialized linkages exist between the deep-sea benthos and sea surface primary production and there is therefore a strong rationale for making sustained observations of this particular faunal group. For example, bio-essential carotenoids, synthesized by cyanobacteria, but not by deep-sea benthic organisms, have the potential to regulate life processes on the seafloor (Wigham et al. 2003; Hudson et al. 2004). It is known that faunal shifts on the deep-sea floor can occur rapidly (FP5 BENGAL). Continuous recording is necessary in order to quantify these changes and to determine how rapidly they occur. Environmental impact surveys measure changes Description of Work EuroSITES Collaborative Project 17 against a baseline survey but what happens when that baseline moves naturally with time? In the deep sea, large invertebrates, such as sea cucumbers, feed directly on detritus gathering at the sediment surface. Changes in their abundance and species composition are good indicators of environmental change and can be achieved relatively cheaply and easily through the use of bottom topography.

The aim of this task is to use photographic transects and time-lapse photography landers at the PAP observatory to monitor changes in abyssal megafauna and relate these to water column processes (WP 3).