Transport and retention of dormant copepods in the Gulf of Maine
Abstract
Variability in the availability of dormant copepods to seed productive shelf areas has been hypothesized to influence the abundance of the dominant copepod species Calanus finmarchicus in several regions of the North Atlantic. One source of this variability is advection of dormant copepods in deep water. Using Lagrangian particle simulations, we examined the influence of environmental forcing and copepod behavior on transport and retention of dormant C finmarchicus in the deep Gulf of Maine, in the northwestern Atlantic. Retention in the Gulf of Maine was relatively high, > 40% over 6 months, under all conditions simulated. Transport within the Gulf of Maine was high, resulting in shifts of eastern copepods into the western Gulf and of upstream copepods, from slope and Scotian Shelf waters, into the eastern Gulf. Copepod behavior during dormancy was a major source of uncertainty, but it is probably not a major source of interannual variability in retention. Retention increased with the initial depth of dormant copepods, and vertical positioning behavior had a strong influence on retention for simulations started at depths greater than 150 m, because copepods that can stay below basin sill depths are retained. Mean cross-shore winds reduced retention slightly (< 2% absolute difference), and mean alongshore winds increased retention by 4-8%. Wind-driven interannual variability in retention was low. Variability in Scotian Shelf inflow had a greater influence on retention than did variability in winds, and inflow-driven changes in retention may contribute to interannual variability in copepod abundance associated with changes in deep-water temperature. However, estimates of advective loss are relatively low compared to measured reductions in dormant copepod abundance, and mortality is probably a major factor in this reduction. (c) 2006 Elsevier Ltd. All rights reserved.
Department
Earth Sciences
Publication Date
11-1-2006
Journal Title
Deep Sea Research Part II-Topical Studies in Oceanography
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Digital Object Identifier (DOI)
10.1016/j.dsr2.2006.08.016
Document Type
Article
Recommended Citation
Johnson, Catherine; Pringle, James M.; and Chen, Changsheng, "Transport and retention of dormant copepods in the Gulf of Maine" (2006). Deep Sea Research Part II-Topical Studies in Oceanography. 18.
https://scholars.unh.edu/earthsci_facpub/18
Rights
Copyright 2006 Elsevier Ltd. All rights reserved