The distribution of colloidal and particulate bioactive metals in Narragansett Bay, RI

摘要: Abstract The bioactive metals Fe, Mn, Cu, Zn and Ni in Narragansett Bay, RI, were partitioned into soluble, colloidal particulate size fractions using a combination of conventional cross-flow filtrations. Particulate samples (0.2–8.0 μm; >8 μm) chemically fractionated acetic-acid reactive non-reactive metals. Conventional “dissolved” ( Mn>Zn>Cu>Ni with concentrations the 0.2–0.8 μm fraction being generally higher than >8.0 fraction. acid leachable phase increased from ∼32%–80% order Fe 8.0 less labile small particulates μm). represented an average 4%–96% metals, ranging importance (96%)>Cu (44%)>Ni (25%)>Zn (7%)>Mn (4%). Although small, Mn was highest region bay where biomass typically is high. Changes soluble along transect through indicate that significant proportion Cu transferred to via colloid aggregation. Predicting metal measurements mass C p ) literature values partition coefficients K c underestimated measured by 5–50×. Acetic particle (0.2–8 correlated well larger (8 kDa–0.2 r =0.91–0.99). In contrast, smaller (1–8 kDa) for most part independent any parameters. Metals not distributed equally between classes; associated colloids (>90%), primarily (∼70–85%) but also fraction, while ≳70% colloids. non-uniform distribution within classes indicates metal:colloid associations are regulated specific interactions. These findings suggest it inappropriate employ single, non-specific sorbing tracers (e.g. Th) delimit pathways kinetics interactions marine