Feeding responses of krill to the toxin-producing diatom Pseudo-nitzschia
Yükleniyor...
Tarih
2003
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Bv
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Krill are important grazers on diatoms and critical prey items for many high level carnivores in Monterey Bay and elsewhere along the California coast. Here, some of the higher level consumers have recently been shown to be severely affected by the toxin, domoic acid (DA), a secondary metabolite of some species of the diatom Pseudo-nitzschia. To understand the potential role of krill in vectoring DA from diatoms to large predators, several grazing experiments were conducted. Field-collected Euphausia pacifica and Thysanoessa spinifera were fed on a diet of toxic and nontoxic Pseudo-nitzschia species. Gut evacuation rates of krill and CHN analysis of the algae were obtained concurrently to determine gut residence time and nutritional value of the food. Our results from a short-term (6 h) grazing experiment demonstrated that both E. pacifica and T spinifera consumed toxic Pseudo-nitzschia multiseries but the responses of the two krill species differed to a degree, with E. pacifica having the higher weight-specific feeding rate. Results from a longer-term (24 h) grazing experiment showed that E. pacifica had a different, interrupted grazing pattern and showed no immediate ill effects when consuming toxic P. multiseries as contrasted with its more constant feeding pattern on non-toxic Pseudo-nitzschia pungens. We show that toxin loads in krill digestive tracts, estimated from feeding rates and gut residence time measured here, match the observed body burdens of DA measured in field-collected krill during toxic blooms. Such data are important for predicting toxin transfer from krill to higher trophic levels during blooms of toxic algae. As an example of this transfer, we show the vulnerability of a krill-feeding seabird, Cassin's Auklet (Ptychoramphus aleuticus) to DA likely vectored by krill during toxic Pseudo-nitzschia blooms. (C) 2002 Elsevier Science B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
herbivores, feeding behavior, krill, Pseudo-nitzschia, domoic acid, Cassin's auklet
Kaynak
Journal of Experimental Marine Biology and Ecology
WoS Q Değeri
Q1
Scopus Q Değeri
Q2
Cilt
284
Sayı
1-2
