Showing papers by "Edward A. Boyle published in 1981"

On the Distribution of Copper, Nickel, and Cadmium in the Surface Waters of the North Atlantic

Abstract: Concentrations of copper, nickel, and cadmium have been determined for about 250 surface water samples. Nonupwelling open-ocean concentrations of these metals are Cu, 0.5-1.4 nmol/kg; Ni, 1-2 nmol/kg; and Cd, less than 10 pmol/kg. In the equatorial Pacific upwelling zone, concentrations of Ni (3 nmol/kg) and Cd (80 pmol/kg) are higher than in the open ocean, but Cu (0.9 nmol/kg) is not significantly enriched. Metal concentrations are higher in cool, nutrient-rich eastern boundary currents: Cu, 1.5 nmol/kg; Ni, 3.5 nmol/kg, and Cd, 30--50 pmol/kg. Copper is distinctly higher in the coastal waters of the Gulf of Panama (3-4 nmol/kg) and also higher in the shelf waters north of the Gulf Stream (2.5 nmol/kg); these copper enrichments may be caused by copper remobilized from mildly reducing sheff sediments and maintained by a coastal nutrient trap. In the open ocean, events of high-Cu water (1.5-3.5 nmol/kg) are seen on scales up to 60 km; presumably, these are due to the advection of coastal water into the oceanic interior. The lowest copper concentrations in the North Pacific central gyre (0.5 nmol/kg; (Bruland, 1980)) are lower than in the Sargasso Sea (1.3 nmol/kg), while for nickel the lowest concentrations are 2 nmol/kg in both the North Pacific and the North Atlantic. Nickel and cadmium, while generally correlated with the nutrients in surface waters, show distinct regional changes in their element-nutrient correlations. The residual concentrations of trace metals in the surface waters of the ocean can be explained if biological discrimination against trace metals relative to phosphorus increases as productivity decreases.

On the distribution of copper, nickel, and cadmium in the surface waters of the North Atlantic and North Pacific Ocean

Abstract: Concentrations of copper, nickel, and cadmium have been determined for about 250 surface water samples. Nonupwelling open-ocean concentrations of these metals are Cu, 0.5–1.4 nmol/kg; Ni, 1–2 nmol/kg; and Cd, less than 10 pmol/kg. In the equatorial Pacific upwelling zone, concentrations of Ni (3 nmol/kg) and Cd (80 pmol/kg) are higher than in the open ocean, but Cu (0.9 nmol/kg) is not significantly enriched. Metal concentrations are higher in cool, nutrient-rich eastern boundary currents: Cu, 1.5 nmol/kg; Ni, 3.5 nmol/kg, and Cd, 30–50 pmol/kg. Copper is distinctly higher in the coastal waters of the Gulf of Panama (3–4 nmol/kg) and also higher in the shelf waters north of the Gulf Stream (2.5 nmol/kg); these copper enrichments may be caused by copper remobilized from mildly reducing shelf sediments and maintained by a coastal nutrient trap. In the open ocean, events of high-Cu water (1.5–3.5 nmol/kg) are seen on scales up to 60 km; presumably, these are due to the advection of coastal water into the oceanic interior. The lowest copper concentrations in the North Pacific central gyre (0.5 nmol/kg; (Bruland, 1980)) are lower than in the Sargasso Sea (1.3 nmol/kg), while for nickel the lowest concentrations are 2 nmol/kg in both the North Pacific and the North Atlantic. Nickel and cadmium, while generally correlated with the nutrients in surface waters, show distinct regional changes in their element-nutrient correlations. The residual concentrations of trace metals in the surface waters of the ocean can be explained if biological discrimination against trace metals relative to phosphorus increases as productivity decreases.

The chemical mass balance in the Amazon plume I: The nutrients

Abstract: In May and June 1976, the Amazon plume was dominated by a diatom blood centered on the 10 x 10−3 isohaline. The bloom was apparently initiated by the increased transparency produced by the rapid settling of the fluvial detrial load. The bloom removes the nitrate and phosphate from the surficial layer. The underlying salt wedge was enriched by remineralisation of planktonic debris. A balance between the dissolved and particulate material shows that the regeneration was essentially complete for carbon and phosphorus; but about 50% of the nitrogen was unaccounted for, having been solubilised to species other than nitrate and nitrite. Only 20% of the silica removed as diatoms (∼25% of the river dissoled flux) could be accounted for as salt wedge enrichment. The rest must have been incorporated in the sediment. The composition of the river waters was strongly affected, before entry to the mixing zone, by remineralisation of a large fraction of the fluvial particulate organic material in the broad area of multi-channel flow above the mouth.