The Bottom Fauna Communities and Their Sediment Relationships off the Coast of Northumberland

Abstract

A quantitative survey has been carried out over an area of about 750 square miles of the North Sea adjacent to the southern half of the Northumberland coast. Bottom samples were obtained with a 0.1 sq.m. Van Veen type grab and supplemented by trawls and dredges. The grab was weighted to 71 kg and fitted with endless warp rig. The position of sampling stations was determined by 'Decca Navigator'. The area with sampling stations and depths is shown in Fig. 1. The bottom slopes gently to a depth of about 70 m. where a trough of deep water, 80-100 m., penetrates down into the area from the Farn Deeps in the North. This deep water ends just south of the Tyne and represents the most southerly limits of the 80 m. and 90 m. contours in the North Sea. The general conditions of temperature and salinity over the area have been derived by averaging the accumulated data of thirteen years observations at the three hydrographic stations marked in Fig. 1. The average bottom temperature conditions are shown in Table 1. The salinity conditions are so stable that they can be discounted as a factor contributing to community differentiation in this area.