37 - Seabed Habitats of the Southern Irish Sea

Abstract

The Irish Sea is one of the busiest maritime regions of the United Kingdom and Ireland, and has great economic value to both countries in terms of its fisheries, aggregate resources, oil and gas reserves, and offshore power generation The sea contains a channel running along its center roughly oriented north–south and gradually shelves on both sides. Three primary sources of water movement exist through the southern Irish Sea—tidal flows, weather-related and density-driven movements. Of these, tidal flows are the most significant, with residual currents flowing in a northward direction through the area. A gradient of increasing salinity exists from north to south, and seasonal fronts are known to form to the north and south of the study area. However, tidal mixing is sufficient across much of the region to ensure that the water column remains well mixed throughout the year. The morphology and sediments of the southern Irish Sea are products of historic glacigenic processes and subsequent exposure to waves, storms, and tidal flows. The Irish Sea Ice Stream poured into the Irish Sea several times during the Quaternary period, and multiple generations of glacial incisions have been documented. Main pressures from anthropogenic activities come from fishing, dredging, shipping, and power generation, and the sea has been classified as a high impact area. Climate change impacts are also becoming evident from rising sea levels and temperature, the latter bringing about a gradual change in the biology of seabed communities in the eastern Irish Sea, and contributing to the spread of non-native species.