Variations in the intertidal and subtidal macrofauna and sediments along a salinity gradient in the upper forth estuary

Abstract

The intertidal and subtidal soft-sediment macrofauna of the upper Forth estuary, eastern Scotland, UK has been examined. The intertidal fauna was sampled in 1977, and again in 1988/89, at up to twelve stations along the salinity gradient. The subtidal fauna was sampled in 1982 and in 1988/89 at up to 15 stations. The stations span the region of the freshwater-seawater interface, and area of the turbidity maximum. Large spatial and temporal variations in macrofaunal abundance and species composition were observed. Sites at the head of the estuary with low salinity were dominated by oligochaetes, but more saline areas were characterised by a depauparate estuarine fauna. The area has historically received large quantities of organic waste both from sewage and industrial discharges which supported very high abundances of oligochaetes of up to 500,000 m-2 in the upper reaches of the estuary. Reductions in the organic inflow to the area since the early-1980's have begun to cause reductions in oligochaete populations and also allowed the further penetration intertidally of non-oligochaete species into the upper and middle reaches of the estuary. No comparable upstream penetration by the non-oligochaete subtidal fauna has been observed, possibly on account of the greater sediment instability in the estuary's main channel.

Contrasting effects of the polychaetes Marenzelleria viridis and Nereis diversicolor on benthic metabolism and solute transport in sandy coastal sediment

“…M. viridis is an invasive species that originates from North America and was first reported in Europe around 1980 in the Forth Estuary, Scotland (McLusky et al 1993). It rapidly spread along the mainland coasts of the North Sea (Essink & Kleef 1988, 1993 and reached the western Baltic Sea in 2004 (Bastrop & Blank 2006). An almost simultaneous spread of the sibling species Marenzelleria neglecta occurred in the southern and central Baltic Sea (Sikorski & Bick 2004).…”

Effects of freshwater input on shallow-water infaunal communities in Doubtful Sound, New Zealand

“…Generally, these studies report a diminishing number of benthic species along gradients from marine to brackish water, with lowest taxonomic richness occurring in waters of salinity 4 to 6, though seasonality and variations in the salinity regime are important components of the observed relationship (Boesch 1977, Gainey & Greenberg 1977, McLusky et al 1993, Ysebaert et al 1993, Schlacher & Wooldridge 1996, Attrill & Power 2000. A corollary is that changes brought to the salinity gradient and pattern in salinity variation can induce large shifts in community composition and ecosystem function within estuaries (e.g.…”

Oxygen dynamics and porewater transport in sediments inhabited by the invasive polychaete Marenzelleria viridis

“…The invasive polychaete Marenzelleria viridis that originates from the east coast of North America was first reported in Europe around 1980 in the Forth Estuary, Scotland (McLusky et al 1993). It rapidly spread along the European mainland coasts (Essink & Kleef 1988) and reached the Danish west coast around 1990 (Jensen & Knudsen 2005) and the western Baltic Sea in 2004 (Bastrop & Blank 2006).…”