A long-term perspective on the Chrysochromulina bloom on the Norwegian Skagerrak coast 1988: a catastrophe or an innocent incident?

Abstract

The long-term effects of the 1988 algal bloom (Chrysochromulina polylepis Manton et Parke) along the Norwegian Skagerrak coast are evaluated and discussed on the basis of several monitoring programmes. Effects on individual growth and survival of coastal cod and its population dynamics are analysed. Cod suffered a high mortality from June until November, and the 1988 yearclass was strongly reduced. Growth was only slightly affected. Furthermore, the effects at the community level are evaluated for the coastal fish community and the benthic communities. These communities were strongly affected on a short time scale, but recovered surprisingly fast. Populations of most organisms had recovered within months, and after 1 yr few traces of the toxic bloom could be observed; after 4 to 5 yr all communities had essentially recovered. As part of the review we also discuss to what extent harmful blooms are likely to reoccur, and conclude that blooms have reoccurred and will continue to do so. However, nothing can be concluded about the toxicity of such blooms. We expect that even large perturbations are unlikely to leave any profound long-lasting effects. The effects of the 1988 bloom are discussed within a theoretical framework including stability, resilience and inertia. In conclusion we emphasise the importance of long-term monitoring data; without such data the analyses reported in this paper would have been impossible.

World’s largest macroalgal bloom caused by expansion of seaweed aquaculture in China

“…It also represents the largest known translocation of any green-tide and the satellite images presented here demonstrates that similar to phytoplankton blooms (Gjøster et al, 2000), under suitable oceanographic conditions green-tides can move large distances adding huge biomass and causing significant damage far from their source. Mass cultivation of valuable seaweed has been encouraged as a remediating measure for tackling eutrophication of coastal waters in China and some other countries (Cuomo et al, 1993;Lüning and Pang, 2003;Fei, 2004).…”

Environmental forcing as a main determinant of bloom dynamics of theChrysochromulinaalgae

“…The focal group of algae, Chrysochromulina spp., exhibited an extensively harmful bloom in the Skagerrak and Kattegat (figure 1) during the late spring and summer of 1988 (Dahl et al 1989;Gjøsaeter et al 2000). The bloom killed a wide range of wild organisms as well as farmed fish.…”

Vertical structure of small eukaryotes in three lakes that differ by their trophic status: a quantitative approach

“…Although Haptophyta are well known in marine systems (Moon-van der Staay et al, 2000; Iglesias-Rodriguez et al, 2002), especially because of their ability to form toxic blooms (Gjøsaeter et al, 2000;Baker et al, 2007), only a dozen Haptophyta species have been previously described from freshwater or terrestrial habitats (John et al, 2002). However, some haptophyte blooms have been previously recorded in different lacustrine systems (Nicholls et al, 1982;Hansen et al, 1994), suggesting an importance of this group in other freshwater ecosystems.…”