Individual-based models of copepod populations in coastal upwelling regions: implications of physiologically and environmentally influenced diel vertical migration on demographic success and nearshore retention

Authored by HP Batchelder, CA Edwards, TM Powell

Date Published: 2002

DOI: 10.1016/s0079-6611(02)00035-6

Sponsors: United States National Oceanic and Atmospheric Administration (NOAA)

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

We link a two-dimension coastal upwelling circulation hydrodynamic-ecosystem (NPZ) model with an individual-based model (IBM) for an intermediate sized (ca. 2.5 mm) copepod capable of diel vertical migration (DVM) at larger sizes. The NPZ model is that of Franks, Wroblewski and Flierl (1986), with the zooplankton state variable parameterized for macrozooplankton. IBM simulations are done with different scenarios for behavioral responses; the interaction of the organisms with the circulation is evaluated by examining growth/development, reproduction, survival and distribution. Since ocean productivity in coastal upwelling systems is greatest nearshore, zooplankton production is favored by nearshore retention. Model results, using an idealized, intermittently wind-forced, upwelling circulation, indicate that non-migrating copepods are flushed from the nearshore system in offshore zonal surface flow; highest population abundances occur offshore, in a region of relatively low food resources. Conversely, migrating copepods interact with the stratified zonal flow within the upwelling system and are retained nearshore when the amplitude of the DVM is sufficient to place the individuals in near-bottom onshore flow during the day. Environmental features, like deep-extending food resources, and physiological controls, like satiation or body size, that permit copepods to remain deeper, or spend more time away from the surface, favor nearshore retention. Diel vertical migration is one mechanism, which may permit animals to exploit favorable habitats located nearshore in upwelling systems. (C) 2002 Elsevier Science Ltd. All rights reserved.

Tags

Ecosystem model Continental-shelf North-atlantic Calanus-finmarchicus Random-walk models Lagrangian ensemble model Chlorophyll maximum Plankton processes Metridia-pacifica Transition zone