California Current Ecosystem - United States of America
California Current Ecosystem
United States of America
carbon and nutrient cycling
Pelagic water column
The CCE-LTER site is a coastal upwelling ecosystem. The study region encompasses the southern sector of the California Current System, extending from San Diego northward beyond Monterey Bay and from the shoreline to ~ 500 km offshore. The California Current (CC) proper forms the eastern limb of the large, clockwise circulation of the subtropical gyre of the North Pacific Ocean. As part of the water from the Westwind Drift turns southward and becomes the California Current, it carries cool, fresh water from the Subarctic Pacific. The California Current System off central and southern California includes the broad, eddy-rich southward flowing California Current; a persistent but variable subsurface California Undercurrent centered on the continental slope that carries water of tropical origin poleward; and a circulation over and near the continental shelf that is energetic and highly seasonal, shifting from a wind-driven equatorward flow and coastal upwelling in spring-summer to poleward flow in fall-winter (Hickey 1998). The pelagic ecosystem of the CCE-LTER site is forced by atmospheric and ocean processes on multiple spatial (local, regional, and basin) and temporal (diel through decadal) scales.
General Characteristics, Purpose, History
Research at the CCE-LTER site focuses on mechanisms leading to transitions over time between different states of the pelagic ecosystem. Observations from the remarkable California Cooperative Oceanic Fisheries Investigations (CalCOFI) coastal ocean time series — now in its 8th decade of sampling — demonstrate the effects of external factors in forcing alterations to this ecosystem on multiple time scales. These factors include a warming trend that has been documented over the past 7 decades, the long term warming and cooling cycles (ca. 20-30 years) represented by the Pacific Decadal Oscillation, forcing by the North Pacific Gyre Oscillation, and the year-to-year temperature fluctuations dominated by El Niño-Southern Oscillation (ENSO). Combinations of these processes, together with interactions among living organisms, can lead to ecosystem responses that may be manifested as relatively abrupt transitions.
Affiliation and Network Specific Information