The Ecological Significance of the Submarine Discharge of Groundwater

Johannes, RE

doi:10.3354/meps003365

Cited by 499 publications

(262 citation statements)

References 20 publications

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“…doi:10.1016/j.csr. 2005.11.008 ocean from a coastal aquifer) can be a significant contributor of nutrients and freshwater to the coastal environment under certain conditions (Johannes, 1980;Valiela et al, 1990;Krest et al, 2000;Paytan et al, 2006;Shellenbarger et al, in review). Locally, groundwater inputs to the coastal zone can have major effects on geochemical cycles either through the discharge of fresh groundwater or the recirculation of seawater through shoreline aquifers (Buddemeier, 1996;Moore, 1997Moore, , 1999.…”

Section: Article In Pressmentioning

confidence: 99%

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Boehm

Paytan

Shellenbarger³

et al. 2006

Continental Shelf Research

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The coastal, unconfined aquifer at Huntington Beach, California contains saline groundwater (33 psu) adjacent to the water line, and a brackish groundwater (BGW) mixing zone (3-9 psu) approximately 50 m from the water line. According to salinity and water isotope analyses, the BGW composition varies spatially in the alongshore direction. Measurements obtained from two BGW wells indicate this water is a mixture of seawater and a freshwater end member (likely infiltrated runoff); results from a third more southerly well suggest the BGW is composed of seawater, freshwater, and water from the confined Talbert Aquifer. Saline groundwater, on the other hand, shares similar salinity and water isotopic composition with seawater. The saline groundwater is enriched with short-and long-lived radium isotopes relative to the surf zone, which in turn is enriched relative to waters further offshore. We derive eddy diffusion coefficients for the nearshore using 223 Ra and 224 Ra, and in conjunction with 226 Ra activities, estimate a submarine groundwater discharge (SGD) rate between 4.2 and 8.9 L min À1 m À1 of shoreline, respectively. Using analytical models, we estimate that between 74 and 100% of this discharge represents seawater than has been forced by tides and waves through the beach aquifer. Under one set of model assumptions, results indicate that a portion (up to 56%) of seawater pumped into the beach aquifer by waves and tides is not discharged suggesting salt water intrusion may be occurring. Because saline groundwater is enriched with dissolved inorganic nitrogen and soluble reactive phosphate relative to the coastal ocean, our results suggest that tidally and wave-driven seawater circulated through the beach aquifer represents an important mechanism for nutrient input to the nearshore environment in dry weather. Estimates of nutrient flux to the coastal ocean via SGD along 16-17 km of shoreline are equivalent to nutrient fluxes from two salt water wetlands near the study site during the dry season. r

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Section: Article In Pressmentioning

confidence: 99%

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Boehm

Paytan

Shellenbarger³

et al. 2006

Continental Shelf Research

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“…Since early suggestions that groundwater may be a major source of nutrients to the ocean [Johannes, 1980], a number of field investigations have demonstrated the biogeochemical implications of SGD. While the earlier SGD literature focused on nutrient fluxes, in the last few years there has been increased research on carbon cycling and the biological implications of SGD.…”

Section: Nutrients Carbon and Greenhouse Gasesmentioning

confidence: 99%

Groundwater dynamics in subterranean estuaries of coastal unconfined aquifers: Controls on submarine groundwater discharge and chemical inputs to the ocean

Robinson¹,

Xin²,

Santos³

et al. 2018

Advances in Water Resources

215

148

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Sustainable coastal resource management requires sound understanding of interactions between coastal unconfined aquifers and the ocean as these interactions influence the flux of chemicals to the coastal ocean and the availability of fresh groundwater resources. The importance of submarine groundwater discharge in delivering chemical fluxes to the coastal ocean and the critical role of the subterranean estuary (STE) in regulating these fluxes is well recognized. STEs are complex and dynamic systems exposed to various physical, hydrological, geological, and chemical conditions that act on disparate spatial and temporal scales. This paper provides a review of the effect of factors that influence flow and salt transport in STEs, evaluates current understanding on the interactions between these influences, and synthesizes understanding of drivers of nutrient, carbon, greenhouse gas, metal and organic contaminant fluxes to the ocean.Based on this review, key research needs are identified. While the effects of density and tides are well understood, episodic and longer-period forces as well as the interactions between multiple influences remain poorly understood. Many studies continue to focus on idealized nearshore aquifer systems and future work needs to consider real world complexities such as geological heterogeneities, and non-uniform and evolving alongshore and cross-shore morphology. There is also a significant need for multidisciplinary research to unravel the interactions between physical and biogeochemical processes in the STE, as most existing studies treat these processes in isolation. Better understanding of this complex and dynamic system can improve sustainable management of coastal water resources under the influence of anthropogenic pressures and climate change.

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“…Moreover, it is now recognized that ground water can be an important global pathway for transport of materials from the land to coastal ecosystems and the oceans (for example, see Johannes, 1980;Simmons, 1992;Church, 1996;Moore, 1996Moore, , 1999Basu and others, 2001;and Burnett and others, 2002).…”

Section: Figure 3 Ground-water Flow Paths In An Idealized Coastal Wamentioning

confidence: 99%

Ground water in freshwater-saltwater environments of the Atlantic Coast

Barlow¹

2003

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The Ecological Significance of the Submarine Discharge of Groundwater

Cited by 499 publications

References 20 publications

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Composition and flux of groundwater from a California beach aquifer: Implications for nutrient supply to the surf zone

Groundwater dynamics in subterranean estuaries of coastal unconfined aquifers: Controls on submarine groundwater discharge and chemical inputs to the ocean

Ground water in freshwater-saltwater environments of the Atlantic Coast

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