The prediction of nutrients into estuaries and their subsequent behaviour: application to the Tamar and comparison with the Tweed, U.K.

Uncles, R.J.; Fraser, A. I.; Butterfield, D.; Johnes, Penny J; Harrod, T. R.

doi:10.1007/978-94-017-2464-7_21

Cited by 11 publications

(18 citation statements)

References 14 publications

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“…Inter-tidal sediment from a salt marsh was resuspended in overlying saline water for 48 h to determine the extent of AA release and their subsequent behaviour. Since nitrate concentrations can reach 250 lM in the Tamar Estuary (Uncles et al 2002), the effectiveness of the modified acid hydrolysis method was evaluated at this concentration, which is within the range commonly reported for anthropogenically impacted estuaries (e.g. Middelburg and Nieuwenhuize 2000).…”

Section: Introductionmentioning

confidence: 99%

Distributions, cycling and recovery of amino acids in estuarine waters and sediments

2007

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Acid hydrolysis of estuarine water samples for the determination of amino acids (AAs) was tested and found to be effective at high (250 lM) nitrate concentrations when the anti-oxidant, ascorbic acid, was added to the samples. Hydrolysable AA concentrations were then determined in surface sediments collected from low and high salinity regions of the Tamar Estuary (UK) during winter 2003 and 2004, and in overlying water when simulated resuspension of sediment particles was performed. Concentrations of AAs in sediment samples comprised <50% of particulate nitrogen, fitting the paradigm that most sedimentary nitrogen is preserved within an organic matrix. When sediment samples were resuspended in overlying water (salinity 17.5), the rapid, measured increase in dissolved AA concentrations almost equalled the reported nitrate concentration in the lower estuary, with the subsequent decrease in the total dissolved AA levels suggested that bacterial uptake was occurring. Our data concur with previous studies on nitrogen desorption from sediments and suggest that an understanding of organic nitrogen cycling will be an important aspect of future effective estuarine management.

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Section: Introductionmentioning

confidence: 99%

Distributions, cycling and recovery of amino acids in estuarine waters and sediments

2007

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“…Higher high winter freshwater flows due to climate change and associated increased river sediment loads due to greater soil erosion in the catchment and nutrient loads (e.g. Uncles et al, 2002b) will result in abrasion of the estuary's bed and increased estuarine turbidity, as well as the potential for eutrophication and other water quality issues such as dissolved oxygen 'sags' in a system that is already recognised to be moderately vulnerable to nutrient enrichment and is considered to have a tendency towards eutrophication (Parr and Wheeler, 1996).…”

Section: Discussionmentioning

confidence: 99%

Seasonal variability of turbidity, salinity, temperature and suspended chlorophyll in a strongly tidal sub-estuary: The Lynher Marine Conservation Zone

Uncles

Hooper²,

Stephens

et al. 2018

Estuarine, Coastal and Shelf Science

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The Lynher Estuary in southwest England is a small, strongly tidal sub-estuary of the Tamar Estuary. It is a Site of Special Scientific Interest (SSSI), a Marine Conservation Zone (MCZ), a part of the Plymouth Sound and Estuaries Special Area of Conservation (SAC) and a Special Protection Area (SPA). Management of the Lynher SSSI and MCZ stipulates that good water quality and sediment quality should be maintained; as such, a good understanding of its responses to influences such as climate change and changes in agricultural practices within its catchment area is required. Observations of salinity, temperature, suspended particulate matter (SPM) concentrations, estuarine turbidity maximum (ETM) behaviour, and chlorophyll-a are presented for the Lynher over a 1-y period. The dataset provides important baseline information with which to identify future changes and guide management of the SSSI and MCZ as well as adding to our knowledge of estuarine systems. Salt intrusion is largely controlled by tides and runoff. A persistent ETM occurs that is closely associated with the freshwater-saltwater interface at high water (HW) and with a minimum in dissolved oxygen concentrations. HW depth-averaged ETM magnitudes are relatively low, less than 60 mg l-1 and typically 30 mg l-1 over the observation period. Larger tides and stronger floodtide wind speeds lead to a stronger ETM. Tidal river HW SPM concentrations are intrinsically small (8±8 mg l-1 during the observation period). Surface chlorophyll-a concentrations are low during winter (when they often peak near the ETM) and are much higher during spring and summer.

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“…Much of the upper estuary is nutrient-rich, with the majority of nutrients from diffuse sources including agricultural run-off and sewerage discharge, although annual mean concentrations of NO x -N, NH 4 -N, PO 4 -P and SiO 2 -Si are similar to other UK rural rivers (Tappin et al, 2013 (Uncles et al, 2002;Tappin et al, 2013) and surface water concentrations greatly exceed those required under current water quality legislation (Howden and Burt, 2009;Burt et al, 2011a).…”

Section: Pollutant Concentrationsmentioning

confidence: 96%

Plymouth — A World Harbour through the ages

Knights

Firth

Thompson

et al. 2016

Regional Studies in Marine Science

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The prediction of nutrients into estuaries and their subsequent behaviour: application to the Tamar and comparison with the Tweed, U.K.

Cited by 11 publications

References 14 publications

Distributions, cycling and recovery of amino acids in estuarine waters and sediments

Distributions, cycling and recovery of amino acids in estuarine waters and sediments

Seasonal variability of turbidity, salinity, temperature and suspended chlorophyll in a strongly tidal sub-estuary: The Lynher Marine Conservation Zone

Plymouth — A World Harbour through the ages

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