Relative roles of coastal and oceanic processes in determining physical and chemical characteristics of an intensively sampled nearshore system

Abstract

We compared the extent to which offshore and remote-sensing measurements of sea surface temperature (SST), upwelling, and chlorophyll a (Chl a) were concordant with in situ measurements of temperature, Chl a, and water nutrients at Tatoosh Island, Washington for the past 8 yr. Offshore SSTs were significantly correlated with water temperatures at Tatoosh, though consistently 2°C to 3°C warmer. Sea-viewing wide field-of-view sensor Chl a estimates were poor predictors of Chl a at Tatoosh Island measured with an anchored fluorometer. Nitrate and phosphorus estimates at Tatoosh Island were positively correlated with an upwelling index and negatively correlated with SST, as would be expected from an upwelling source. In contrast, ammonium and nitrite were uncorrelated with the upwelling index or SST and showed elevated levels immediately adjacent to Tatoosh Island, suggesting strong local effects of marine invertebrates, birds, and mammals on nutrient dynamics and cycling in coastal ecosystems. © 2007, by the American Society of Limnology and Oceanography, Inc.