A study of the role of physico-chemical factors in the control of the distribution of invertebrates in the Aln estuary, N. E. England

The role of physico-chemical factors in controlling the distribution of invertebrates was investigated at Aln estuary, Alnmouth, North East England. A general account is given of the intertidal benthic macrofauna at twelve stations along a 2.4 km tidal stretch of the Aln estuary from the open coast inland. Species distribution was interpreted in relation to selected physico-chemical factors. Salinity was the factor to which all species had to respond to. However, it was found that not one, but several interrelated factors were operative in limiting the distribution of each species. A detailed study was made of Corophium volutator and Haustorius arenarius. It was found that salinity and sediment characteristics were the most important factors influencing the distribution of these two species. Although not enough time was available to quantify biological factors, the interrelationship between physico- chemical factors and biological factors was not dismissed, and the potential role of biological factors in determining the distribution of the intertidal benthic macrofauna was emphasized.