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Meanders of the shelf break front in the Mid-Atlantic Bight (MAB) during April and May of 1997 were associated with chlorophyll enhancement along a hydrographic and a topographic feature. The hydrographic feature was the surface outcrop of the front, which ranged from ∼10 to >100 km seaward of the shelf break owing to the meanders. The topographic feature was the shelf break (100-m isobath). Chlorophyll enhancement was observed by a satellite instrument, the ocean color and temperature sensor, and by a fluorometer in situ. It developed in near-surface waters typically nutrient depleted during late spiring, thus local nutrient enrichment of near-surface waters was probable. Observations of sufficient resolution to define processes were available only for the region of shelf break chlorophyll enhancement. Along two meander troughs (shoreward extremities near the shelf break), we observed shoaling of cold shelf water. Shelf water shoaled >20 m along frontal isopycnals, and phytoplankton absorption maxima coincided directly with the shoaled water. Thus local nutrient enrichment by along-isopycnal upwelling was the supported mechanism of chlorophyll enhancement at the shelf break. The basis for along-isopycnal upwelling was seaward flow of shelf water forced by meander circulation near the shelf break. Strong cross-isobath flow and mixing developed as these meanders propagated along the shelf break front of the MAB at a relatively constant rate of ∼9 km day-1. Copyright 1999 by the American Geophysical Union.

The Galician shelf off NW Spain (43N° 9W°) exhibits mesoscale spatial and temporal changes in biological productivity associated with upwelling. Spatial heterogeneity results from local geomorphic and land-sea interactions superimposed on the large scale atmospheric processes that produce upwelling. Wind-induced upwelling events, commonly of short (i.e., week) duration, are more common in the summer than in the winter. A series of cruises, including some time series sampling, and satellite imagery analysis showed that surface upwelling was more common and persistent on the northern coast compared with the western coast off the coastal embayments, the Rias Bajas. Near shore off the rias, coastal runoff, which is greater in the rainy winter/spring versus the dry summer, affected upwelling. In early summer, upwelling less often reaches the surface because of increased water column stratification associated with lower surface salinities and thus upwelling is not detected by satellite imagery. Conversely, in late summer, upwelling more often reaches the surface because coastal runoff is reduced during the dry summer months and the water column tends to be less stratified. Plankton biomass and rate processes along the Galician shelf reflected both ambient hydrographic conditions as well as prior history of upwelling or downwelling. Phytoplankton and bacterioplankton were in greatest abundance during upwelling conditions (June through August); in contrast, both Zooplankton and fish larvae exhibited highest abundances in March, when there were upwelling conditions prior to our cruise. Spatial differences in the duration and frequency of upwelling events, in combination with advection of water masses, are critical to the patterns of water column productivity and sardine fisheries production off the Galician coast. More persistent upwelling at this NW corner of the Iberian peninsula supports large sardine fisheries because Zooplankton and larval fish populations have time to

The Galician shelf off NW Spain (43N° 9W°) exhibits mesoscale spatial and temporal changes in biological productivity associated with upwelling. Spatial heterogeneity results from local geomorphic and land‐sea interactions superimposed on the large scale atmospheric processes that produce upwelling. Wind‐induced upwelling events, commonly of short (i.e., week) duration, are more common in the summer than in the winter. A series of cruises, including some time series sampling, and satellite imagery analysis showed that surface upwelling was more common and persistent on the northern coast compared with the western coast off the coastal embayments, the Rias Bajas. Near shore off the rias, coastal runoff, which is greater in the rainy winter/spring versus the dry summer, affected upwelling. In early summer, upwelling less often reaches the surface because of increased water column stratification associated with lower surface salinities and thus upwelling is not detected by satellite imagery. Conversely, in late summer, upwelling more often reaches the surface because coastal runoff is reduced during the dry summer months and the water column tends to be less stratified. Plankton biomass and rate processes along the Galician shelf reflected both ambient hydrographic conditions as well as prior history of upwelling or downwelling. Phytoplankton and bacterioplankton were in greatest abundance during upwelling conditions (June through August); in contrast, both Zooplankton and fish larvae exhibited highest abundances in March, when there were upwelling conditions prior to our cruise. Spatial differences in the duration and frequency of upwelling events, in combination with advection of water masses, are critical to the patterns of water column productivity and sardine fisheries production off the Galician coast. More persistent upwelling at this NW corner of the Iberian peninsula supports large sardine fisheries because Zooplankton and larval fish populations have time to

CoOP (Coastal Ocean Processes) is an organization meant to study major interdisciplinary scientific problems in the coastal ocean. Its goal is to obtain a new level of quantitative understanding of the processes that dominate the transformations, transports and fates of biologically, chemically and geologically important matter on the continental margin. Central to obtaining this understanding will be advances in observing and modeling the cross-shelf component of transport. More specific objectives are to understand (1) cross- margin exchanges, (2) air sea exchanges, (3) benthic-pelagic exchanges, (4) terrestrial inputs and (5) biological and chemical transformations within the water column. CoOP research will be carried out primarily through a series of process-oriented field studies, each involving about two years of measurements. Each of these field studies is to be initiated and defined through a community workshop. In addition to the process studies, CoOP will also involve modeling, long time series, exploratory studies, remote sensing, technological innovation, data archiving and communications. A CoOP pilot study has been approved for funding by the National Science Foundation, and funding will begin in 1992. The CoOP science effort is thus already underway.... Coastal oceanography, Coastal meteorology, Continental shelf.