A DNA test to sex most birds.

Coastal hydrogeologists and oceanographers now recognize the potentially significant contribution that submarine groundwater discharge (SGD) could make to the coastal ocean. SGD may be both volumetrically and chemically important to coastal water and chemical budgets. A worldwide compilation of observed SGD shows that groundwater seepage from the land to the ocean occurs in many environments along the world’s continental margins. Further, SGD has a significant influence on the environmental condition of many nearshore marine environments and provides a strong motivation for improved assessments. Our review reveals a critical lack of data from coastal zones of almost all parts of the world, especially in South America, Africa and parts of Asia, making a comprehensive compilation incomplete. SGD should be paid more attention with regard to water and dissolved material budgets at the local and global scales. SGD intercomparison experiments and coastal typologies (classification) may enable evaluation of the accuracy of the SGD estimates and up-scaling of SGD to a global scale. Copyright  2002 John Wiley & Sons, Ltd.

Investigation of submarine groundwater discharge

The premise of this article is that climate effects on lakes can be quantified most effectively by the integration of process-oriented limnological studies with paleolimnological research, particularly when both disciplines operate within a common conceptual framework. To this end, the energy (E)-mass (m) flux framework (Em flux) is developed and applied to selected retrospective studies to demonstrate that climate variability regulates lake structure and function over diverse temporal and spatial scales through four main pathways: rapid direct transfer of E to the lake surface by irradiance, heat, and wind; slow indirect effects of E via changes in terrestrial development and subsequent m subsidies to lakes; direct influx of m as precipitation, particles, and solutes from the atmosphere; and indirect influx of water, suspended particles, and dissolved substances from the catchment. Sedimentary analyses are used to illustrate the unique effects of each pathway on lakes but suggest that interactions among mechanisms are complex and depend on the landscape position of lakes, catchment characteristics, the range of temporal variation of individual pathways, ontogenetic changes in lake basins, and the selective effects of humans on m transfers. In particular, preliminary synthesis suggests that m influx can overwhelm the direct effects of E transfer to lakes, especially when anthropogenic activities alter m subsidies from catchments.

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Paleolimnological evidence of the effects on lakes of energy and mass transfer from climate and humans

The importance of groundwater discharge to the methane budgets of nearshore and continental shelf waters of the northeastern Gulf of Mexico

This chapter provides a review of the current state of knowledge on submarine groundwater discharge (SGD) and the associated fluxes of nutrients, trace metals, microbes, pharmaceuticals, and other terrestrial constituents to coastal waters. We review methods of estimating SGD, present flux estimates from different locations worldwide, and discuss how various hydrogeologic features such as topography, aquifer substrate, climate, waves, and tides affect SGD. We discuss the range of nutrient and metal concentrations observed in groundwater and their relationship to land use, and explore the chemical changes that nutrients and metals undergo during their seaward journey through the aquifer. Climate change is likely to affect both the quantity and the quality of SGD, and we investigate these effects, which are only beginning to be studied. The chapter concludes with a discussion of active areas of SGD research, including expanding the geographic scope of SGD studies; characterizing and reducing the uncertainty associated with SGD measurements; understanding the behavior of nutrients, metals, and other pollutants in the subterranean estuary; and modeling SGD on a global scale.

4.08 – Submarine Groundwater Discharge: A Source of Nutrients, Metals, and Pollutants to the Coastal Ocean

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1991.36.6.1250

Reconstruction of a regional, 12,‐yr silica decline in lakes by means of fossil sponge spicules

A method has been tested for manually driving piezometers into the bottom sediments of surface waters. It allows piezometers to be driven from a surface working platform and after installation leaves a flexible piezometer line that does not pose a safety hazard on the water surface. The piezometer line may be attached to a float on the water surface or be extended to the shoreline enabling measurement of hydraulic head and geochemical sampling. These piezometers have been successfully installed in 6 to 8 meters (m) of water, 40 m offshore and 2 to 2·5 m below the sediment surface in medium- to fine-grained sand.

A method for installing and monitoring piezometers in beds of surface waters

Discharge of groundwater contaminant plumes has created elevated concentrations of Sr in some aquatic sediments at Chalk River Laboratories. Tree swallows (Tachycenita bicolor) feed and supply their nestlings almost exclusively with airborne insects that developed as larvae in aquatic sediments. To monitor the uptake and test for potential detriment due to Sr in a terrestrial animal, we measured the gross beta concentrations in the bone of 12-d-old tree swallow nestlings in areas having sediments with elevated levels of gross beta (Sr and Y) and in several control areas where sediment gross beta was primarily due to naturally occurring K. Nesting behavior and reproductive success of the tree swallows were similar regardless of the gross beta concentrations in sediments near their nest boxes. Radiation can damage DNA and cause micronuclei to form in cells, so we examined the frequency of micronuclei in erythrocytes of nestlings. The formation of micronuclei in the erythrocytes of the nestlings was also similar wherever nestlings were analyzed. The results revealed no significant increases even near sediments with the highest gross beta levels. At Perch Lake, where Chalk River Laboratories has a large area of Sr-contaminated sediments, the bones of 12-d-old nestlings contained gross beta concentrations as high as 29 Bq g. This would produce a skeletal dose rate of 9 μGy h, which is one-fourth of the threshold dose rate of 40 μGy h, above which detriment could occur. Failing to find any indication of detriment in the field study, we irradiated wild eggs in the lab and returned them to their nest for natural incubation, hatching, and feeding by the parents. There was an increase in formation of micronuclei following a dose of 3.2 Gy, and the other results were consistent with existing literature.

David Robert Lee

Papers

Reconstruction of a regional, 12,‐yr silica decline in lakes by means of fossil sponge spicules

A method for installing and monitoring piezometers in beds of surface waters

Effects of 90Sr on Tree Swallow Nestlings Near Groundwater Contaminant Plumes.