No abstract

No abstract

No abstract

No abstract

The overall effect of the number of boats on the copper (Cu) levels in the water column and sediment along with their spatial variability within Shelter Island Yacht Basin (SIYB), San Diego Bay, California was examined. We identified a horizontal gradient of increasing dissolved Cu and Cu in sediment from outside to the head of SIYB. which was coincident with the increasing number of boats. Spatial models of Cu distribution in water and sediment indicated the presence of "hot spots" of Cu concentration. From outside to the head of SIYB, dissolved Cu ranged from 1.3 µg L-1 to 14.6 µg L-1 , in surface water, and 2.0 to 10.2 µg L-1 in bottom water. Cu in sediment exceeded the Effect Range Low of 34 mg kg-1 (i.e. where adverse effects to fauna may occur), with a peak concentration of 442 mg kg-1 at the head of the basin. "Free" Cu ++ in surface water was several orders of magnitude higher than in sediment porewater. High-resolution data of Cu species together with probability maps presented in this paper will allow managers to easily visualize and localize areas of impaired quality and to prioritize which areas should be targeted to improve Cu-related conditions.

No abstract

We examined Cu contamination effects on macrobenthic communities and Cu concentration in invertebrates within Shelter Island Yacht Basin, San Diego Bay, California. Results indicate that at some sites, Cu in sediment has exceeded a threshold for "self defense" mechanisms and highlight the potential negative impacts on benthic faunal communities where Cu accumulates and persists in sediments. At sites with elevated Cu levels in sediment, macrobenthic communities were not only less diverse but also their total biomass and body size (individual biomass) were reduced compared to sites with lower Cu. Cu concentration in tissue varied between species and within the same species, reflecting differing abilities to "regulate" their body load. The spatial complexity of Cu effects in a small marina such as SIYB emphasizes that sediment-quality criteria based solely on laboratory experiments should be used with caution, as they do not necessarily reflect the condition at the community and ecosystem levels.

Estudios oceanográficos recientes han demostrado que las aguas superficiales del Golfo de California (GC) están enriquecidas con metales traza (Cd, Ni y Mn) en relación a las aguas superficiales del Océano Pacifico adyacente (Delgadillo