The status of phosphorus of a calcareous flush at Bakethin Reservoir, Northumberland

In order to assess the status of phosphorus of a calcareous flush at Bakethin reservoir, Northumberland, chemical analyses of the concentration of phosphorus in the water and the phosphatase activity of cyanobacteria, Nostoc and Rivularia, as well as the bryophytes, Drepanocladus revolvens and Cratoneuron commutatum, were performed. Concentrations of total filterable phosphorus ranged from 0.11 to 11.35 μg I(^1) and filtrable reactive phosphorus ranged from below detection to 10.55 μg I(^1) No statistical difference was determined in concentrations of phosphorus at different sites in the flush, but a significant difference was determined between different sampling dates, at <0.05. Phosphatase activity in the cyanobacteria, Rivularia and Nostoc, varied between different sites and different dates. Nostoc showed a consistently higher rate of phosphatase activity than Rivularia. Activity in both the cyanobacteria showed no correlation between filtrable reactive and filtrable organic content of the water. Phosphatase activity in the bryophytes, Drepanocladus revolvens and Cratoneuron commutatum, had its pH maximum in the acidic range. Activity also varied between sampling dates and between different species

Shellfish toxicity in UK waters: a threat to human health?

The potential for poisoning of humans through their consumption of shellfish which have themselves consumed biotoxin producing marine phytoplankton exists in the UK. Toxins are bio-accumulated within the shellfish flesh allowing them to reach harmful concentrations. This threat is in most part mitigated by monitoring programmes that assess both the presence of potentially harmful phytoplankton and shellfish flesh toxicity. However, the medical profession in the UK remains relatively ignorant of the potential for biotoxin derived shellfish toxicity, preventing quantification of magnitude, frequency, and severity of health effects in the community or the medical significance of more recently discovered toxins. While the current causative species and their toxins are relatively well characterised there remains a lack of understanding of the factors governing the temporal and spatial appearance of harmful phytoplankton. Expansion of shellfish aquaculture is likely both worldwide and in the UK. Better understanding of how harmful phytoplankton interact with their environment to promote the sporadic harmful blooms that we observe is required to underpin risk assessments

mNCEA policy brief - PELCAP: Natural Capital in Plankton & Pelagic Habitats

This policy brief fact sheet descries ecosystem services provided by pelagic habitats and a natural capital accounting of the the economic contribution pelagic habitats provide to the UK, as estimated by the Office of National Statistics. Plankton is vital for the functioning of marine ecosystems but is hard to value monetarily. According to the Office of National Statistics, plankton in UK waters provides services valued at up to 3.4 £ billion per year. PHEG members think that this is an underestimate. This project was funded by the Department for Environment, Food and Rural Affairs (Defra) as part of the marine arm of the Natural Capital and Ecosystem Assessment (NCEA) programme. The marine NCEA programme is leading the way in supporting Government ambition to integrate natural capital approaches into decision making for the marine environment. Find out more at https://www.gov.uk/government/publications/natural-capital-and-ecosystem-assessment-programm

Inter- and intra-annual bacterioplankton community patterns in a deepwater sub-Arctic region:Persistent high background abundance of putative oil degraders

Oil spills at sea are one of the most disastrous anthropogenic pollution events, with the Deepwater Horizon spill providing a testament to how profoundly the health of marine ecosystems and the livelihood of its coastal inhabitants can be severely impacted by spilled oil. The fate of oil in the environment is largely dictated by the presence and activities of natural communities of oil-degrading bacteria

Seasonal variability of the carbonate system and coccolithophore Emiliania huxleyi at a Scottish Coastal Observatory monitoring site

Lack of information about carbonate chemistry in inshore waters is a ‘knowledge gap’ in assessing the impacts of changing carbonate chemistry on the marine environment. Assessing the response of calcifying phytoplankton to this changing carbonate chemistry requires a greater understanding of temporal variation. This study provides a description of the variability of carbonate parameters at a monitoring site in the eastern coast of Scotland. Four-years of monthly data were analysed to assess the diversity, abundance and morphometrics of coccolithophores in relation to carbonate chemistry and environmental variables. The seasonality in carbonate parameters reflected the seasonal cycle in phytoplankton activity, with higher total alkalinity concentrations and pH and lower dissolved inorganic carbon concentrations during the growing season. The dominant coccolithophore at the site was Emiliania huxleyi which showed a clear seasonal pattern, being more abundant in mid-summer when warmer and nutrient-depleted conditions restricted the annual diatom bloom. This study revealed the presence of three morphotypes of E. huxleyi, type A, type A overcalcified (type AO) and type B, which were seasonally distributed throughout the year. The less calcified form was mainly observed in spring while heavily calcified morphotypes overlapped during summer. Autumn and winter months were dominated by the most calcified form (type AO). These results indicate that the seasonal pattern of E. huxleyi morphotypes was not related to the carbonate concentration at the site. This study reflects the strong interannual variability in carbonate chemistry and the complexity associated with coccolithophore calcification, and highlights the need of long-term data to understand the potential impact of ocean acidification on calcifying phytoplankton

mNCEA policy brief - Plenty more fish in the sea? Counting the cost of climate change on marine Natural Capital

This policy brief describes how predicted changes in productivity across the Atlantic will impact the amount of fish that the marine environment can support. This is bound to have important implications for marine food webs and our continued sustainable use of marine resources. Plankton form the foundation of commercially-valuable food chains to fish • Warming, stratification and reduced nutrient supply has already reduced plankton stocks • Reduced phytoplankton also means less efficient food chains • Even a modest (16-26%) continued decline in phytoplankton will magnify into a 38-55% decline in harvestable fish across the north Atlantic • Hotspots of this future decline in fish are in present-day fishing grounds • This risk-mapping approach provides a forward look for spatial protection and management This project was funded by the Department for Environment, Food and Rural Affairs (Defra) as part of the marine arm of the Natural Capital and Ecosystem Assessment (NCEA) programme. The marine NCEA programme is leading the way in supporting Government ambition to integrate natural capital approaches into decision making for the marine environment. Find out more at https://www.gov.uk/government/publications/natural-capital-and-ecosystem-assessment-programm

The onset of the spring phytoplankton bloom in the coastal North Sea supports the Disturbance Recovery Hypothesis

The spring phytoplankton bloom is a key event in temperate and polar seas, yet the mechanisms that trigger it remain under debate. Some hypotheses claim that the spring bloom onset occurs when light is no longer limiting, allowing phytoplankton division rates to surpass a critical threshold. In contrast, the Disturbance Recovery Hypothesis (DRH) proposes that the onset responds to an imbalance between phytoplankton growth and loss processes, allowing phytoplankton biomass to start accumulating, and this can occur even when light is still limiting. Although several studies have shown that the DRH can explain the spring bloom onset in oceanic waters, it is less certain whether and how it also applies to coastal areas. To address this question at a coastal location in the Scottish North Sea, we combined 21 years (1997-2017) of weekly in situ chlorophyll and environmental data with meteorological information. Additionally, we also analyzed phytoplankton cell counts estimated using microscopy (2000-2017) and flow cytometry (2015-2017). The onset of phytoplankton biomass accumulation occurred around the same date each year, 16 ± 11 d (mean ± SD) after the winter solstice, when light limitation for growth was strongest. Also, negative and positive biomass accumulation rates (r) occurred respectively before and after the winter solstice at similar light levels. The seasonal change from negative to positive r was mainly driven by the rate of change in light availability rather than light itself. Our results support the validity of the DRH for the studied coastal region and suggest its applicability to other coastal areas

Investigations into the relationship between domoic acid and copepods in Scottish waters

This study investigated impacts of the algal toxin domoic acid (DA) on copepods in Scottish waters. Inspection of seasonal patterns revealed that several common copepods (Acartia spp. Dana, 1846, Calanus spp. Leach, 1816, Centropages spp. Krøyer, 1849, Pseudocalanus spp. Boeck, 1872, and Temora longicornis (Müller O.F., 1785)) regularly coexist with potentially toxic species from the diatom genus Pseudo-nitzschia H. Peragallo in H. Peragallo and M Peragallo, 1900. A short field study investigating the DA content of Calanus spp. at the Scottish Coastal Observatory site at Stonehaven recorded DA during every sampling event. The highest DA levels were associated with a July bloom (∼135000 cells L−1) of Pseudo-nitzschia cf. plurisecta Orive & Pérez-Aicua 2013. Several studies have previously investigated effects of ingested DA on copepods but information on effects of dissolved DA is lacking, therefore, simple exposure experiments were carried out to measure mortality of copepod species at ecologically relevant concentrations of dissolved DA. The highest concentrations tested (≥ 50 ng DA mL−1) decreased survival in Temora longicornis only; survival of other copepod species was unaffected. However, T. longicornis feeding on non-toxic algae in the presence of dissolved DA did not accumulate DA in their tissue. This study provides evidence of the potential for Calanus spp. to act as vectors for DA to higher trophic levels in Scottish waters

High-CO2 Levels Rather than Acidification Restrict Emiliania huxleyi Growth and Performance

The coccolithophore Emiliania huxleyi shows a variety of responses to ocean acidification (OA) and to high-CO2 concentrations, but there is still controversy on differentiating between these two factors when using different strains and culture methods. A heavily calcified type A strain isolated from the Norwegian Sea was selected and batch cultured in order to understand whether acclimation to OA was mediated mainly by CO2 or H+, and how it impacted cell growth performance, calcification, and physiological stress management. Emiliania huxleyi responded differently to each acidification method. CO2-enriched aeration (1200 µatm, pH 7.62) induced a negative effect on the cells when compared to acidification caused by decreasing pH alone (pH 7.60). The growth rates of the coccolithophore were more negatively affected by high pCO2 than by low pH without CO2 enrichment with respect to the control (400 µatm, pH 8.1). High CO2 also affected cell viability and promoted the accumulation of reactive oxygen species (ROS), which was not observed under low pH. This suggests a possible metabolic imbalance induced by high CO2 alone. In contrast, the affinity for carbon uptake was negatively affected by both low pH and high CO2. Photochemistry was only marginally affected by either acidification method when analysed by PAM fluorometry. The POC and PIC cellular quotas and the PIC:POC ratio shifted along the different phases of the cultures; consequently, calcification did not follow the same pattern observed in cell stress and growth performance. Specifically, acidification by HCl addition caused a higher proportion of severely deformed coccoliths, than CO2 enrichment. These results highlight the capacity of CO2 rather than acidification itself to generate metabolic stress, not reducing calcification.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Funding for open access charge: Universidad de Málaga / CBUA This work was funded by FC14-RNM-27 research grant (FITOVIA) from the University of Málaga, Spain (Plan Propio) to CJ. VV was funded by a EUROPE ERASMUS+grant to carry out research short-stay at Marine Scotland Marine Laboratory in Aberdeen, UK, and by a grant from the University of Málaga, Spain (Plan Propio)