Chatham / Challenger project - Voyage 2 Sea-bed Ecology - Chatham Rise
Planning for the biological sampling voyages in 2007 was complex and required a rigorous approach to designing a sampling programme that would result in measures of biodiversity and characterisation of habitats in the survey area. A pragmatic approach also had to be developed because of the logistics of sampling the sea-bed in relatively deep water.
Using the multibeam data from Voyage 1, scientists at NIWA were able to identify 9 areas with distinct acoustic or environmental signals on the Chatham Rise. These areas or ‘strata’ were used as a basis for allocating biological sampling stations in Voyage 2.
Each colour in the map represents a stratum, and the small lines mark the approximate location of a sampling station. A trade-off between achieving broad coverage across the whole survey area and detailed sampling at individual locations had to be made.
A range of sampling tools are being deployed. Some of the stations will get ‘the works’ (sediment corer, sled, beam trawl, cameras and videos, all replicated twice). Others will be sampled with just the sled and camera system, and some will just be viewed by the camera system.
As the Voyage progresses [see weekly Voyage diary from the ship] stations will be added or dropped depending on how kind the weather is and how long it takes to process the samples.
It can take hours to sieve through mud samples and select out every creature for identification counting and weighing. There is a team of 21 scientists on board the ship. They are split into 2 groups so that sampling and processing can proceed 24-7.
The Chatham Rise survey is for 30 days.