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At least 631 records · Page 35Linked to original sources
USGS1977

Effects of dredged channels on trace-metal migration in an estuary

Determination of trace-metal levels in the sediments of the Matagorda Bay system revealed anomalously high mercury values. The distribution of the mercury-rich sediment deposits is the result of the sedimentological regime of the bay system produced by the tidal currents in the dredged channel. According to this model, the oxygenated open gulf water pushed into the bay by tidal currents activates the mercury and reintroduces it into the sediment regime of the bay in an area where the turbidity maximum is most prevalent. Within this region, the absorption sites are at a maximum, tying up the mercury. The mercury-enriched suspended material is then transported and deposited according to the hydraulic regime within the bay system.

Texas↗
USGS2024

Current and future potential ecosystem services of the Nisqually River Delta: An assessment approach for Puget Sound estuaries and USFWS coastal refuges

The Nisqually River Delta, located in South Puget Sound, contains a rich mosaic of different coastal habitat types. The goal of this project was to quantify ecosystem services — benefits that wildlife or ecosystems provide to people — that are priorities for the Billy Frank Jr. Nisqually National Wildlife Refuge, the Nisqually Indian Tribe, and the surrounding communities. We modeled how change in these habitats from sea level rise (SLR) or management activities like restoration could affect ecosystem services in the future. We focused on changes to three main ecosystem services: soil carbon accumulation, birdwatching visitation, and juvenile Chinook salmon growth rates, which served as a proxy for fishery production. A habitat and carbon model projected that after 100 years, most high salt marsh would remain with < 1m SLR, but a substantial area would convert to low salt marsh and mudflat with ≥ 1m SLR. Total carbon accumulation would plateau or decline with ≥ 1m SLR, yet economic value of carbon accumulation would continue to rise over time, suggesting that the value of this ecosystem service is resilient to SLR. Birdwatching visitation was greatest in winter months and was positively related to area of forested wetland, emergent wetland, aquatic vegetation bed (e.g., eelgrass) and mudflat and open access (areas freely accessible to the public). Increases in forested wetland may lead to greater increases in visitation compared to other habitat types. All three ecosystem services increased with increases in forested wetland and emergent wetland, and tradeoffs among services occurred with increases in aquatic vegetation bed and mudflat. While both prey-rich salt marshes and eelgrass meadows facilitate salmon growth, loss of salt marsh led to declines in juvenile salmon weight. In conversation with USFWS managers, we identified practical ways to incorporate ecosystem services into adaptive management frameworks that support climate adaptation decision making. Our study illustrated how accounting for ecosystem services helps managers make decisions that greatly benefit wildlife and people, communicate the societal value of decisions, and increase local engagement and participation.

Washington↗