Organic phosphate in UK rivers and its relevance to algal and bryophyte surveys

Whitton, Brian A.; Neal, Colin

doi:10.1051/limn/2010102

Cited by 23 publications

(9 citation statements)

References 29 publications

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“…Rott et al (2012) mentioned ultraoligotrophic conditions for five Oocardium sites in the Eastern Alps. Compared to middle and lower courses (Whitton and Neal 2011), SAL habitats show considerably lower P amounts. As P limitation cannot be ruled out, the effect of phosphate availability on the algae community in these habitats needs further attention.…”

Section: Discussionmentioning

confidence: 86%

Seasonal succession of the travertine‐forming desmid Oocardium stratum

Linhart

Schagerl

2015

Journal of Phycology

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The calcifying Conjugatophyte Oocardium stratum occurs exclusively in spring-associated limestones (SAL) with active meteogene limestone deposition. The macroscopic colonies of Oocardium stratum form hemispherical, pinhead-like structures with a diameter of 0.5-2.0 mm. As its autecology is still poorly understood, we focused on the seasonal development of Oocardium stratum and linked environmental factors to its abundance. The study was conducted in a rivulet in Lunz/See (Austria) for 16 months on a weekly (growing season) to monthly (winter season) basis. Oocardium colonies were found throughout the whole year, with maximum abundance during the mid-summer months July and August. Repeated macro-mapping of three SAL sites measuring 750 cm(2) each showed a maximum Oocardium cover of around 30% in August; two smaller peaks developed in early summer and late autumn with ~10% cover. Diatom mats dominated by Cymbella excisiformis occurred in spring, autumn and winter, with more than 75% cover. The seasonal change between Oocardium and diatoms in limestone-precipitating springs causes a typical sequence pattern of limestone layers. Redundancy analysis revealed water temperature and bicarbonate content as the main structuring factors; these control the occurrence and growth of Oocardium, reflecting season as a background variable. Optimum growth conditions for Oocardium were an alkalinity around 4.7 meq · L(-1) and a water temperature around 13°C. Site openness, nitrate and dissolved carbon dioxide were inversely related to Oocardium biomass, the opposite for diatoms. Other environmental factors such as total ions or soluble reactive phosphorus had no significant influence on Oocardium stratum abundance.

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Section: Discussionmentioning

confidence: 86%

Seasonal succession of the travertine‐forming desmid Oocardium stratum

Linhart

Schagerl

2015

Journal of Phycology

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“…The majority of DHP is considered to be organic, and significant, but variable amounts of utilizable DHP have been monitored in land runoff (e.g. Darch et al 2014), and in UK rivers (Whitton and Neal 2011). As farming systems recycle more P in bioresources and adopt more agro-ecological approaches to soil management in the future (Withers et al 2014b), one can anticipate that the ecological importance of the DHP fractions will increase.…”

Section: Does Lowering Of Stp Alter the Forms Of P In Runoff?mentioning

confidence: 99%

Reducing soil phosphorus fertility brings potential long-term environmental gains: A UK analysis

Withers

Hodgkinson

Rollett

et al. 2017

Environ. Res. Lett.

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Soil phosphorus (P) fertility arising from historic P inputs is a major driver of P mobilisation in agricultural runoff and increases the risk of aquatic eutrophication. To determine the environmental benefit of lowering soil P fertility, a meta-analysis of the relationship between soil test P (measured as Olsen-P) and P concentrations in agricultural drainflow and surface runoff in mostly UK soils was undertaken in relation to current eutrophication control targets (30-35 mg P L À1 ). At agronomic-optimum Olsen P (16-25 mg kg À1 ), concentrations of soluble reactive P (SRP), total dissolved P (TDP), total P (TP) and sediment-P (SS-P) in runoff were predicted by linear regression analysis to vary between 24 and 183 mg L À1 , 38 and 315 mg L À1 , 0.2 and 9.6 mg L À1 , and 0.31 and 3.2 g kg À1 , respectively. Concentrations of SRP and TDP in runoff were much more sensitive to changes in Olsen-P than were TP and SS-P concentrations, which confirms that separate strategies are required for mitigating the mobilisation of dissolved and particulate P forms. As the main driver of eutrophication, SRP concentrations in runoff were reduced on average by 60 mg L À1 (71%) by lowering soil Olsen-P from optimum (25 mg kg À1 ) to 10 mg kg À1 . At Olsen-P concentrations below 12 mg kg À1 , dissolved hydrolysable P (largely organic) became the dominant form of soluble P transported. We concluded that maintaining agronomic-optimum Olsen-P could still pose a eutrophication risk, and that a greater research focus on reducing critical soil test P through innovative agro-engineering of soils, crops and fertilisers would give long-term benefits in reducing the endemic eutrophication risk arising from legacy soil P. Soil P testing should become compulsory in priority catchments suffering, or sensitive to, eutrophication to ensure soil P reserves are fully accounted for as part of good fertiliser and manure management.

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“…All analyses for chemical variables were made according to American Public Health Association (1998). PO 4 -P was measured as filterable reactive P (FRP) and the filterable hydrolysable fraction, which is treated as filterable organic P (FOP) here, though the possibility that colloidal inorganic P might be included would require detailed study of the water chemistry (Whitton & Neal, 2011).…”

Section: Sampling Programmementioning

confidence: 99%

Ecology, morphology and physiology ofChroothece richteriana(Rhodophyta, Stylonematophyceae) in the highly calcareous Río Chícamo, south-east Spain

Aboal

García-Fernández

Roldán

et al. 2014

European Journal of Phycology

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The ecology of Chroothece was studied in the highly calcareous Río Chícamo, south-east Spain, in order to explain its success there, but rarity elsewhere. The river, which originates mainly from an underground aquifer, has water with high conductivity, sulphate and nitrate but low phosphate concentrations, the latter mainly organic. Chroothece occurs in mats and in lobed colonies reaching 4 cm in the broadest dimension. The colony surface consists of one layer of cells, each of which is attached to a stalk, which dichotomizes when the cell divides; stalks often extend to the colony base. The central region of many mat cells and almost all colony cells has a yellow to orange-brown colour, associated with the numerous lipid droplets densely covering the surface of the pyrenoid and arms of the star-shaped chloroplast. Field material and laboratory isolates indicate that stalk formation occurs under moderate P limitation and both stalks and cell sheath show high phosphatase activities. This also occurred in a culture collection strain maintained for 30 years in a very P-rich medium, but then transferred to a moderately P-limiting medium (c. 0.9 mg l −1 ). We suggest that colony formation is initiated by aggregation of motile cells following P pulses in the water. Comparisons are made with Rivularia, a competitor in this nitrate-rich river, in spite of being a N 2 -fixer. One difference is that Chroothece cells lie at the periphery of the colonies and are therefore exposed to maximum sunlight, whereas Rivularia trichomes grow inside colonies with photoprotection by scytonemin. However, the ability to withstand heavy grazing pressure may be an especially important factor favouring Rivularia here.

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Organic phosphate in UK rivers and its relevance to algal and bryophyte surveys

Cited by 23 publications

References 29 publications

Seasonal succession of the travertine‐forming desmid Oocardium stratum

Seasonal succession of the travertine‐forming desmid Oocardium stratum

Reducing soil phosphorus fertility brings potential long-term environmental gains: A UK analysis

Ecology, morphology and physiology ofChroothece richteriana(Rhodophyta, Stylonematophyceae) in the highly calcareous Río Chícamo, south-east Spain

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