Living (stained) benthic foraminifera within surficial sediments of the Skagerrak

Abstract

An analysis of living (stained) benthic foraminifera within four box cores raised from water depths of 74 to 621 m in the Skagerrak shows that faunal patterns at different water depths are strikingly different within this relatively shallow, organicrich marginal sea environment. Although some genera show vertical stratification within the sediments, a number of taxa are found over wide intervals or have different patterns between cores. The vertical distributional data are compared with deep-sea data from the eastern margin of North America. Benthic foraminifera from a deep core at 530 m in the Skagerrak have similar faunal patterns within the surficial sediments as found in the deep sea, but shallow cores at 74 and 212 m have more complex patterns. This difference between shallow and deep cores within the Skagerrak and the North Atlantic is attributed to higher biological activity in the shallow environments, which creates a greater amount of heterogeneity within the shallow-water sediments than is found in deeper environments. The faunal data suggest that the use of benthic foraminifera for paleoenvironmental reconstructions in shallow, organicrich regions will be complicated in future studies. The ecology of individual species is difficult to assess because of the complex faunal patterns observed within the surficial sediments. Geochemical studies for estimating bottom water oxygen or organic carbon flux will also be difficult, since these studies assume that taxa occupy particular microhabitats within the surficial sediments.