Phosphorus Cycling in the Estuarine and Coastal Zones

Slomp, Caroline P.

doi:10.1016/b978-0-12-374711-2.00506-4

Cited by 50 publications

(59 citation statements)

References 259 publications

(264 reference statements)

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“…This is of concern as eutrophic conditions result in systems with high productivity, low species diversity, drastic shifts in community structure, bottom-water hypoxia and proliferations of nuisance and/or harmful aquatic plants (e.g. blue-green algae) (Bricker et al, 2003;Slomp, 2012).…”

Section: Discussion Nutrient Assessment Of River Monitoring Stationsmentioning

confidence: 99%

“…For example, it is known that under natural conditions rivers dominate the input of phosphorus (P) to the marine environment (Slomp, 2012;Statham, 2012); whilst the natural introduction of N to estuaries is dominated (more equally than P) by rivers, groundwater and atmospheric deposition (Jickells and Western, 2012;Voss et al, 2012). It is important to understand that the significance of these allochthonous sources, of both N and P, to a given aquatic system depends on the source composition and proximity, as well as the chemical, biological, and physical characteristics of the receiving system (Voss et al, 2012).…”

Section: Patterns and Trendsmentioning

confidence: 99%

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Nutrient characterisation of river inflow into the estuaries of the Gouritz Water Management Area, South Africa

Lemley

Taljaard²,

Adams³

et al. 2014

WSA

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This study provides an overview of the nutrient status of river inflow into the estuaries within the Gouritz Water Management Area (WMA) of South Africa. Riverine inputs are a major source of macronutrients to estuaries and the adjacent coastal environments. Long-term water quality monitoring data (dissolved inorganic nitrogen, i.e. DIN; and dissolved inorganic phosphorus, i.e. DIP), collected by the Department of Water Affairs (DWA), were used to assess historical trends of river nutrient inflow within the Gouritz WMA. The results indicate that DIP concentrations exceeded the eutrophic limits for aquatic ecosystems (DWA) in 50% of the catchments assessed. Anthropogenic activities such as agriculture, wastewater discharge, urbanisation, and afforestation were significant factors influencing nutrient levels within these rivers. For the majority of the river systems (approx. 80%) there was no significant correlation (P > 0.05) between inorganic nutrient levels and freshwater inflow from the catchments. Wastewater treatment plant (WWTP) data (DWA) were assessed to explore the reasons for this 'disconnect' between freshwater inflow and inorganic nutrient levels. The Gwaing and Hartenbos estuaries would be most vulnerable to increased nutrient loading because of their small size and prolonged periods of mouth closure. The study highlights the importance of water quality monitoring of river inflows into coastal ecosystems, as it is needed to assess pollution trends and identify management priorities.

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Section: Discussion Nutrient Assessment Of River Monitoring Stationsmentioning

confidence: 99%

Section: Patterns and Trendsmentioning

confidence: 99%

Nutrient characterisation of river inflow into the estuaries of the Gouritz Water Management Area, South Africa

Lemley

Taljaard²,

Adams³

et al. 2014

WSA

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“…In contrast, low oxygen conditions in bottom waters may enhance SO 4 2− reduction and ultimately stimulate the release of P from Fe-oxides (Rozan et al 2002). Changes in salinity and bottom water redox conditions can also affect the formation of other Pbearing minerals such as carbonate fluorapatite (CFA) (e.g., Ruttenberg and Berner 1993;Slomp et al 1996;Kraal et al 2012) by influencing porewater alkalinity, dissolved calcium (Ca 2+ ), and dissolved phosphate (predominantly present as HPO 4 2− at seawater pH, simplified in the text as PO 4 ) concentrations through a complex interplay of geochemical and microbial processes (Ruttenberg 2003;Slomp 2011). The resulting changes in burial of sediment P can play a key role in regulating P availability and, subsequently, primary productivity and oxygen consumption in coastal waters (Froelich et al 1982;Ruttenberg 2003).…”

Section: Communicated By David Reide Corbettmentioning

confidence: 99%

“…In addition, water column salinity and water column and bottom water redox conditions can affect the burial of phosphorus (P; Ruttenberg 2003;Slomp 2011), a key nutrient for marine organisms (Tyrrell 1999). For example, a lower salinity is thought to lead to more retention of Fe-oxide-bound P in sediments because of a lower availability of sulfate (SO 4 2− ), and associated lower rates of SO 4 2 − reduction and sulfide(HS − )-induced reduction of Fe-oxides (e.g., Caraco et al 1990;Hartzell et al 2009).…”

Section: Communicated By David Reide Corbettmentioning

confidence: 99%

Holocene Refreshening and Reoxygenation of a Bothnian Sea Estuary Led to Enhanced Phosphorus Burial

Dijkstra

Krupinski

Yamane

et al. 2017

Estuaries and Coasts

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Salinity variations in restricted basins like the Baltic Sea can alter their vulnerability to hypoxia (i.e., bottom water oxygen concentrations <2 mg/l) and can affect the burial of phosphorus (P), a key nutrient for marine organisms. We combine porewater and solid-phase geochemistry, microanalysis of sieved sediments (including XRD and synchrotron-based XAS), and foraminiferal δ 18 O and δ 13 C analyses to reconstruct the bottom water salinity, redox conditions, and P burial in the Ångermanälven estuary, Bothnian Sea. Our sediment records were retrieved during the Integrated Ocean Drilling Program (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013. We demonstrate that bottom waters in the Ångermanälven estuary became anoxic upon the intrusion of seawater in the early Holocene, like in the central Bothnian Sea. The subsequent refreshening and reoxygenation, which was caused by gradual isostatic uplift, promoted P burial in the sediment in the form of Mn-rich vivianite. Vivianite authigenesis in the surface sediments of the more isolated part of the estuary ultimately ceased, likely due to continued refreshening and an associated decline in productivity and P supply to the sediment. The observed shifts in environmental conditions also created conditions for postdepositional formation of authigenic vivianite, and possibly apatite formation, at ∼8 m composite depth. These salinityrelated changes in redox conditions and P burial are highly relevant in light of current climate change. The results specifically highlight that increased freshwater input linked to global warming may enhance coastal P retention, thereby contributing to oligotrophication in both coastal and adjacent open waters.

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“…Nitrifying bacteria, present in the sediment, under oxic conditions (nitrification) convert NH 4 + to NO 2 − to NO 3 − , which can subsequently be released to the water column. Similarly, the flux of phosphate from the sediment is also affected by oxygen levels as well as soil redox potential; the release of PO 4 3− (or SRP) occurs under hypoxic or anoxic conditions (Koop et al, 1990;Slomp, 2012).…”

Section: Introductionmentioning

confidence: 99%

The benthic regeneration of N and P in the Great Brak estuary, South Africa

Human

Snow

Adams

et al. 2016

WSA

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The Great Brak is a temporarily open/closed estuary (TOCE) located on the south coast of South Africa. The construction of the Wolwedans Dam in 1989 reduced baseflow to the estuary by 56%, decreasing the intensity of flushing events and causing the mouth to breach less often. The aim of this study was to investigate the flux of inorganic nutrients (NH 4, SRP) as well as total N and P across the sediment-water interface in the estuary. There have been very few studies on nutrient cycling and benthic pelagic coupling in South African estuaries. This study showed that the sediment had a net efflux of NH 4 + , SRP, TN and TP while TOxN was taken up or converted to other forms of N. The estuary acted as a source of N and P during both summer and winter. If the estuary remains closed for a prolonged period (12 months), with an increased organic load present on the benthos, the associated rates of efflux of N and P would increase. In order to reduce the organic load to the system better flushing methods or, more importantly, an increase in base flow, is needed to reduce residence times of water in the estuary.

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Phosphorus Cycling in the Estuarine and Coastal Zones

Cited by 50 publications

References 259 publications

Nutrient characterisation of river inflow into the estuaries of the Gouritz Water Management Area, South Africa

Nutrient characterisation of river inflow into the estuaries of the Gouritz Water Management Area, South Africa

Holocene Refreshening and Reoxygenation of a Bothnian Sea Estuary Led to Enhanced Phosphorus Burial

The benthic regeneration of N and P in the Great Brak estuary, South Africa

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