RESUMO
Data on particulate strontium sulfate fluxes and strontium to chlorinity ratios were compared to provide insights into the strontium cycle of the North Pacific. Freedrifting sediment traps were used to derive large particle fluxes between depths of 100 and 3500 meters in the eastern and western North Pacific Ocean. Flux data revealed substantial quantities of acantharian skeletons and cysts (both made of strontium sulfate) settling through the upper kilometer of the water column. The greatest fluxes of celestite were detected at 400 meters. Minimal to nondetectable fluxes noted at and below 900 meters provide evidence that by this horizon, the majority of acantharian specimens had dissolved, thereby contributing to the pool of dissolved strontium. Growth and subsequent dissolution of acantharians in the upper kilometer are qualitatively consistent with the well-developed minimum and maximum strontium to chlorinity ratios that are consistently noted in these waters. These fluxes of particulate strontium and model calculations for fluxes of dissolved strontium indicate that acantharians play an important role in the ocean's strontium budget.
RESUMO
Particle-associated pollutants (totaling 10(7) metric tons per year) are introduced into the New York Bight by ocean dumping, estuarine discharge, sewage outfalls, eolian transport, and shipping waste and spillage. Oceanic and estuarine circulation processes dilute and transport the particles by a natural dispersal system that also tends to be highly distributive; particle-associated pollutants apparently seek the same sinks in the Hudson River shelf valley and intracoastal weltlands, regardless of their point of introduction.
RESUMO
Fluxes of biogenic carbonates moving out of the euphotic zone and into deeper undersaturated waters of the North Pacific were estimated with free-drifting sediment traps. Short-duration (1 to 1.5 day) sampling between 100 and 2200 meters points to a major involvement in the oceanic carbonate system by a class of organisms which had been relegated to a secondary role-aragonitic pteropods. Pteropod fluxes through the base of the euphotic zone are almost large enough to balance the alkalinity budget for the Pacific Ocean. Dissolution experiments with freshly collected materials shed considerable light on a mystery surrounding these labile organisms: although plankton collections from net tows almost always contain large numbers of pteropods, these organisms are never a major component of biogenic materials in long-duration sediment trap collections. Their low abundance in long-duration collections results from dissolution subsequent to collection. Shortduration sampling showed significant increases in the ratio of calcitic foraminifera to aragonitic pteropods in undersaturated waters, indicating the more stable mineralogic form, calcite, was preserved relative to aragonite. Approximately 90 percent of the aragonite flux is remineralized in the upper 2.2 kilometers of the water column.
RESUMO
Large numbers of black metallic spherules ranging in diameter from a few micrometers to over 800 micrometers are raining into the eastern Gulf of Mexico and adjacent areas of western Florida. The composition of the flux, its association with glass spherules and coky particles, and its magnitude point to industrial pollution, probably coal- and coke-burning facilities around the perimeter of the gulf, as the source. Since metallic particles represent only a small fraction of most fly ash, such an influx of large numbers of black magnetic spherules must be symptomatic of a much higher rate of sedimentation of fly ash. The internal microstructures and the general appearance of spherules derived from industrial processes are similar to those of particles derived from cosmic sources. Because of the high potential for contamination in micrometeorite studies, a complete compositional verification of each "cosmic" particle may be necessary.
