Four abyssal plain sites: Porcupine, Tagus, Madeira and Cap Verde

Insect and earthworm taxonomy-related abundance per unit area of the bed; Insect and earthworm taxonomy-related ash-free dry weight biomass per unit area of the bed

Unconsolidated sediment corers

The aim of the MAST programme is to describe natural structure and variability in offshore benthic processes; to relate this structure to the physical, chemical and biological environment; and finally to attempt to predict changes associated with natural and anthropogenic disturbance. This project involves eleven institutes from six nations and is coordinated by the Institute of Oceanographic Sciences Deacon Laboratory (IOSDL), Wormley, Surrey, UK. The Natural History Museum has the role of Taxonomy and data control, coordinating and standardising the taxonomic expertise. The Museum is working on the taxonomy and ecology of two infaunal groups from the abyssal plain study sites - the polychaetes and nematodes. Specimens from these sites are currently being sorted, identified and the data used to assess patterns of species richness, equitability and trophic structure. Nematodes: Nematode samples were collected using a SMBA multiple corer. Core samples were subdivided into layers: 0-1cm, 1-2cm, 2-3cm, 3-4cm, 4-5cm, 5-10cm where appropriate. Densities from three cores at the Porcupine and Madeira have been obtained; data are from two cruises to the Porcupine Abyssal Plain (1989 and 1991) and one cruise to the Madeira Abyssal Plain (1990). In addition, the nematodes from the surface 0-1cm layer of the six cores from each site have been identified and analyzed. Data are also available from syringe core sub-samples from each of the sites. It is planned to start analysis of nematodes from the EUMELI site on the Cap Verde Abyssal Plain in collaboration with IFREMER, Centre du Brest, France. Polychaetes: Polychaete samples were obtained with a USNEL spade box corer. Three sites have been investigated: Porcupine, Tagus and Madeira; data from the EUMELI site are also available from COB, France. Samples from the Tagus were collected using a vegematic-divided corer, while those from the Porcupine and Madeira Abyssal Plains were collected using an unmodified box corer. The latter samples were sieved through 1mm, 0.5mm, 0.3mm and 0.25mm sieves and the corer was divided into layers - 0-1cm, 1-3cm, 3-5cm, 5-10cm. Polychaete analysis is continuing to date and there are data on the abundances of polychaetes from all three sites; diversity and taxonomic information is confined to the Tagus. This project is still producing data.

Department of Zoology, Natural History Museum
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United Kingdom