By Natalia Serpetti & Peter Lamont
For this cruise the aim of the benthic group at SAMS was to go “sledging” again at John Gage’s Station ‘M’ to collect “MUD ………glorious, deep-water MUD”.
And we got MUD!
OK here’s the tekki science bit……
It is 40 years since Dave Ellett started measurements in the Rockall Trough, and 18 years since the hydrographic section was extended up to Iceland. In the mid-1970s, as Dave Ellett established his survey line the late John Gage decided to use one of the Ellett stations – ‘M’ – as a regular benthic sampling station (mostly using the epibenthic sledge), located near the foot of Anton Dohrn seamount at 2,200 m depth. The benthic historical samples ended in 1994 and span a time frame of about 25 years: during this time there have been noticeable changes in the sea surface productivity possibly as a consequence of climate change. Our current efforts are directed at assessing the potential effect of plankton primary productivity on the composition of the seabed community. These are the small animals larger than about 0.4 mm that live in and on the mud. In 2013 we have the great opportunity to re-sample the seabed at station “M” with two of the original refurbished epibenthic sleds to provide a new sample point over a 40 year time span record for this gear and position. Collecting this new material will enable us to continue to extend the longest bathyal benthic time-series and to examine differences/similarities in the faunal composition over time.
Back to the practicalities:
The last two days we have been quite hard working……collecting deep-water benthic samples it is never easy, but very rewarding when we manage to get good samples. We got litres and litres of mud to wash onto three stacked sieves of 4, 0.5 and 0.42 millimetres to retain and preserve the small animals that live in and on the seabed surface!
Apparently even the pilot wales love MUD as they followed us all afternoon, getting very close to us….or maybe they liked Penny’s music playlist blasting from a mini speaker beside where we were working on deck!
Photos by Penny Holliday