The zooplankton community structure in relation to its biological and physical environment on the Faroe shelf, 1989-1997

Authors
Citation
E. Gaard, The zooplankton community structure in relation to its biological and physical environment on the Faroe shelf, 1989-1997, J PLANK RES, 21(6), 1999, pp. 1133-1152
Citations number
32
Categorie Soggetti
Aquatic Sciences
Journal title
JOURNAL OF PLANKTON RESEARCH
ISSN journal
01427873 → ACNP
Volume
21
Issue
6
Year of publication
1999
Pages
1133 - 1152
Database
ISI
SICI code
0142-7873(199906)21:6<1133:TZCSIR>2.0.ZU;2-N
Abstract
The Faroe shelf water is separated from the offshore water by a persistent tidal front, which surrounds the islands. This shelf water contains a nerit ic zooplankton community, which, regarding species composition, production, seasonal development and environmental conditions, is quite different from that in the surrounding ocean. While during spring and summer the zooplank ton in the oceanic environment are dominated by the copepod Calanus finmarc hicus, the zooplankton in the shelf water are largely dominated by neritic copepods, mainly Acartia longiremis and Temora longicornis. Calanus finmarc hicus occurs in interannually highly variable abundance in the Faroe shelf ecosystem. Meroplanktonic larvae, mainly Balanus spp. and decapod larvae, a re also common in the shelf water during spring and summer. During the peri od presented (1989-1997), the Faroe shelf ecosystem has undergone very larg e changes in abundance of different zooplankton species. The midsummer abun dance of C.finmarchicus, which originally is advected into the shelf from t he open ocean, fluctuated from similar to 400 copepods m(-3) in 1989 to sim ilar to 25 copepods m(-3) in 1994, and at the same time the neritic zooplan kton increased from similar to 120 m(-3) in 1989 to 450 m(-3) in 1994. Cons equently, the midsummer biomass in the shelf fluctuated by a factor of 10 d uring the same period. It is presumed that this variability between oceanic - and neritic-dominated zooplankton, their sizes and their biomass has grea tly affected the entire pelagic ecosystem.