scholarly journals Long-term changes in the diel vertical migration behaviour of Calanus finmarchicus in the North Sea are unrelated to fish predation

1998 ◽  
Vol 171 ◽  
pp. 307-310 ◽  
Author(s):  
AG Hirst ◽  
SD Batten
Author(s):  
P. E. P. Norton

SynopsisThis is a brief review intended to supply bases for prediction of future changes in the North Sea Benthos. It surveys long-term changes which are affecting the benthos. Any prediction must take into account change in temperature, depth, bottom type, tidal patterns, current patterns and zoogeography of the sea and the history of these is briefly touched on from late Tertiary times up to the present. From a prediction of changes in the benthos, certain information concerning the pelagic and planktonic biota could also be derived.


2001 ◽  
Vol 9 (3) ◽  
pp. 131-187 ◽  
Author(s):  
R A Clark ◽  
C LJ Frid

Long-term data on the North Sea ecosystem are available for phytoplanktonic, zooplanktonic, benthic, fish, and seabird communities. Temporal changes in these have been examined by numerous researchers over the course of the 20th century, their main objective being to determine how the interannual dynamics of these communities are controlled. Ultimately, long-term changes in the North Sea ecosystem appear to be driven by two wide-ranging, but separate processes. In the northern, western and central areas of the North Sea, long-term changes are predominantly influenced by climatic fluctuations. Here, primary productivity during a particular year is related to the effect of weather on the timing of stratification and the resulting spring bloom. In the southern and eastern areas of the North Sea, the lack of stratification and the large inputs of nutrients mean that primary productivity is more strongly influenced by variations in anthropogenic nutrient inputs, and is only weakly related to climatic variation. Long-term changes at higher trophic levels (zooplankton, benthic, fish, and seabirds) are generally affected by fluctuations in their food source (i.e., the lower trophic levels), although because of the high complexity of the North Sea ecosystem there are many exceptions to these general patterns. However, the weight of evidence shows that long-term changes in the ecosystem may ultimately be related to long-term changes in either climate or nutrients, although the long-term dynamics of certain taxa and communities do show evidence of being influenced by both anthropogenic factors and (or) internal factors such as competition and predation. Key words: long-term changes, North Sea, time series, climate change, ecosystem functioning, anthropogenic impacts.


2001 ◽  
Vol 31 (2) ◽  
pp. 107-115 ◽  
Author(s):  
Philip C. Reid ◽  
Martin Edwards

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