Biogeochemical data from surface sediments in the Porcupine Abyssal Plain

Sediment samples were collected in the Porcupine Abyssal Plain (PAP, 4800 m depth) during 6 oceanographic cruises from September 1996 to October 1998 down to a depth of 15 cm. Sedimentary proteins, carbohydrates and lipids, and their enzymatically hydrolysable fractions showed significant temporal changes, but different biochemical classes displayed different temporal patterns.

Total proteins, carbohydrates and lipids displayed high concentrations, whereas the potentially hydrolysable fractions accounted for only about 10% of their total pools. From September 1996 to October 1998, bioavailable organic carbon concentration in the sediments decreased about 10 gC/m**2 indicating that this benthic system was not steady state. Hydrolysed proteins and carbohydrates were characterised by different vertical patterns.