Coastal upwelling in the northern California Current
varies seasonally, with downwelling in winter and upwelling
in summer, resulting in pronounced variability in
hydrography, nutrients, phytoplankton biomass, and species
composition. Winter was characterized by moderate concentrations
of nitrate and silicate (averages of 10 and 18 μM,
respectively) and low concentrations of...
In this study, we assessed trophic interactions between microplankton and copepods by studying the functional response of egg production rates (EPR; eggs female⁻¹day⁻¹) of the copepod Calanus marshallae to variations in microplankton biomass, species composition and community structure. Female C. marshallae and phytoplankton water samples were collected biweekly at an...
The synchrony between coastal and shelf-slope copepod communities was investigated in the northern California Current (NCC) system, a strong upwelling zone, using time series of zooplankton sampled from a nearshore station (9 km offshore, water depth 62 m) and a shelf-slope station (46 km offshore, water depth 297 m). Long-term...
This study addresses the occurrence, severity, and extent of hypoxia over the continental shelf of the northern
California Current (40–48.5°N latitude) from 1998 to 2012. Clear seasonal trends exist in the timing and duration
of hypoxia. The highest bottom-water dissolved oxygen concentrations occurred from November to March, and
levels below...
Unusual collections of several euphausiid, chaetognath, and copepod species help elucidate
the effects of the strong 1997/1998 El Niño off the central Oregon, USA, coast. Furcilia of Nyctiphanes simplex, a euphausiid typically found only as far north as central California, were collected in bi-weekly nearshore samples between December 1997 and...
Fisheries oceanography is the study of ecological relationships between fishes and the dynamics of their marine environments and aims to characterize the physical, chemical, and biological factors that affect the recruitment and abundance of harvested species. A recent push within the fisheries management community is toward ecosystem-based management. Here, we...
Climatic effects in the ocean at the community level are poorly described, yet accurate predictions about ecosystem responses to changing environmental conditions rely on understanding biotic responses in a food-web context to support knowledge about direct biotic responses to the physical environment. Here we conduct time-series analyses with multivariate autoregressive...
Larval supply determines year-class strength of fisheries and complex ecological
interactions among adults of benthic marine species. In upwelling regions, a latitudinal cline in
the intensity and persistence of upwelling is thought to affect larval advection and recruitment,
thereby regulating the intensity of interactions in adult populations and communities. We...
Full Text:
coast of the northeast Pacific Ocean with
strong persistent upwelling (Morgan et al. 2009a,b,
Morgan
The impact of mesoscale eddies on the spatial distribution of zooplankton biomass was analysed using data from the Arabian Sea and the Black Sea. The highest values of spatial variance of zooplankton biomass in the upper 100 to 150 m were found in regions with maximum available potential energy of...