Direct evidence of a biologically active coastal silicate pump: Ecological implications

摘要: Ecological shifts from diatoms to other phytoplankton species have been related decreasing Si:N and Si:P nutrient ratios. The Bay of Brest is such a perturbated ecosystem where Si has become limiting but continue dominate the throughout productive period. Several hypothesis invoked account for this dilemma. most recent combines suspension feeder activity recycling. Suspension activity, stimulated by proliferation invasive Crepidula fornicata, would be driving force biologically active silicate pump which (1) retain within during spring (2) provide necessary summer. During year 2000, was successfully tested. Direct evidence silicic acid limitation provided, summer, benthic fluxes measured at site with high density C. fornicata are one order magnitude higher than those no fornicata. Seasonal budgets inputs diatom demand demonstrated that production summer depends strongly on recycling sediment-water interface. Thus, if decreases biodiversity perturbates development native Great Scallop (Pecten maximus), it also helps cope elevated N inputs. proposed removal might economically desirable fisheries economic viewpoint, clearly associated, in present context excessive inputs, potential risk harmful algal blooms