Applying a ridge-to-reef framework to support watershed, water quality, and community-based fisheries management in American Samoa

Comeros-Raynal, Mia T.; Lawrence, A. J.; Sudek, Mareike; Vaeoso, Motusaga; McGuire, Kim; Regis, Josephine; Houk, Peter

doi:10.1007/s00338-019-01806-8

Cited by 19 publications

(13 citation statements)

References 77 publications

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“…Swarzenski et al [63] measured groundwater discharge from Kahekili Beach Park, Maui, a wastewater affected site, and found average U and V concentrations of 0.8 nmol/L and 291 nmol/L, respectively, which are slightly higher than this study's U and V averages of 0.7 nmol/L and 286 nmol/L. Additionally, Swarzenski et al [5] also found an average Cr concentration of 82.8 nmol/L, which is higher than this study's average Cr concentration of 18.6 nmol/L.…”

Section: Comparison Of Trace Metal Chemistry In Similar Environmentscontrasting

confidence: 51%

“…It is therefore important to better characterize the distribution and observable effects of groundwater contamination sources to support water resource management. Previous studies conducted in American Samoa have found elevated levels of groundwater nitrogen to be one of Tutuila's primary water quality concerns [2,5]. These studies found linkages between watershed population density and dissolved nitrogen in coastal waters, as well as links between groundwater nitrogen in the Tafuna-Leone Plain with wastewater from cesspools, where the prevalent chemical form of nitrogen found in these aquifers is nitrate (NO 3 − ) [2].…”

Section: Introductionmentioning

confidence: 94%

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Metal Mobilization As An Effect of Anthropogenic Contamination in Groundwater Aquifers in Tutuila, American Samoa

Okuhata

Dulai

Shuler

et al. 2020

Water

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Groundwater is the primary drinking water source on most oceanic islands, including Tutuila, American Samoa. Drinking water quality on Tutuila is impacted by anthropogenic pollution sources such as on-site sewage disposal systems, piggeries, and agricultural leachate, particularly across the densely populated Tafuna–Leone Plain. The remineralization of anthropogenically sourced organic matter produces nitrate and dissolved inorganic carbon, which, according to previously published studies, have the potential to mobilize naturally occurring metals. This study provides further evidence that nutrients and dissolved inorganic carbon, along with naturally sourced metal concentrations, become elevated along pollution gradients and show correlation with each other. Across the Tafuna–Leone Plain, nitrate concentrations have a moderately positive correlation with uranium and vanadium. Dissolved inorganic carbon also positively correlate with nitrate, uranium, and vanadium. Similar studies elsewhere suggest that, in addition to nitrate, organic matter remineralization associated with carbonate create conditions to favor natural metal mobilization. Correlation analysis results imply that, while the surveyed trace metals are likely naturally sourced, some become soluble and more mobile in the presence of anthropogenically sourced nitrate and dissolved inorganic carbon, which alters redox conditions in the aquifer.

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Section: Comparison Of Trace Metal Chemistry In Similar Environmentscontrasting

confidence: 51%

Section: Introductionmentioning

confidence: 94%

Metal Mobilization As An Effect of Anthropogenic Contamination in Groundwater Aquifers in Tutuila, American Samoa

Okuhata

Dulai

Shuler

et al. 2020

Water

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“…Because of their low cost and relative simplicity to measure, nutrient concentrations and loads are commonly examined to serve as indicators of human impact. In particular, DIN loading has been found to be one of the most robust metrics for understanding coastal ecosystem impacts and thus remains a major consideration for coastal resource management (Caraco and Cole 1999;Waterhouse et al 2017;Comeros-Raynal et al 2019).…”

Section: Discussionmentioning

confidence: 99%

“…We obtained existing water quality data from stream and coastal spring samples taken throughout Tutuila by Comeros-Raynal et al (2019), Shuler et al (2017. Stream sampling data from Comeros-Raynal (2019) were collected from 38 individual stream sites for a one-year period from September 2016 to September 2017 (Fig 3), and consisted of a total of 424 individual stream samples.…”

Section: Water Sampling and Nutrient Concentrationsmentioning

confidence: 99%

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Ridge to Reef Management Implications for the Development of an Open-Source Dissolved Inorganic Nitrogen Loading Model in American Samoa

Shuler

Comeros-Raynal

2020

Preprint

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Excessive nutrient discharge to tropical island coastlines drives eutrophication and algal blooms with significant implications for reef ecosystem condition and provision of ecosystem services.Management actions to address nutrient pollution in coastal ecosystems include setting water quality standards for discharging surface waters. However, these standards do not account for the effects of groundwater discharge, variability in flow, or dilution, all of which may influence assessment of true nutrient impacts on nearshore reef habitats. We developed a method to estimate dissolved inorganic nitrogen (DIN) loads to coastal zones by integrating commonly available datasets within a geospatial modeling framework for Tutuila, American Samoa. The DIN loading model integrated an open-source water budget model, water sampling results, and publically available streamflow data to predict watershed-scale DIN loading to the island's entire coastline. When compared to surface water pathways, submarine groundwater discharge (SGD) was determined to be the most important coastal delivery mechanism of terrigenous DIN, which supports findings from other tropical islands. Onsite wastewater disposal systems were also found to be the primary anthropogenic sources DIN to coastal waters. Our island-wide DIN loading model provides a simple and robust metric to define spatially-explicit sources and delivery mechanisms of nutrient pollution to nearshore reef habitats. Understanding the sources and primary transport modes of inorganic nitrogen to nearshore reef ecosystems can have significant implications for place-based management interventions aimed at increasing the adaptive capacity of unique island ecosystems to environmental variation and disturbances.

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Ridge to Reef Management Implications for the Development of an Open-Source Dissolved Inorganic Nitrogen-Loading Model in American Samoa

Shuler

Comeros-Raynal

2020

Environmental Management

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Applying a ridge-to-reef framework to support watershed, water quality, and community-based fisheries management in American Samoa

Cited by 19 publications

References 77 publications

Metal Mobilization As An Effect of Anthropogenic Contamination in Groundwater Aquifers in Tutuila, American Samoa

Metal Mobilization As An Effect of Anthropogenic Contamination in Groundwater Aquifers in Tutuila, American Samoa

Ridge to Reef Management Implications for the Development of an Open-Source Dissolved Inorganic Nitrogen Loading Model in American Samoa

Ridge to Reef Management Implications for the Development of an Open-Source Dissolved Inorganic Nitrogen-Loading Model in American Samoa

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