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The first UK records of the purple fan-worm, Bispira polyomma Giangrande & Faasse, 2012 (Annelida: Sabellidae
Get PDFThe sabellid polychaete Bispira polyomma Giangrande & Faasse, 2012 was found
during summer–autumn 2021 in substantial numbers in two adjacent marinas in
Plymouth, SW England. These are apparently the first UK reports, coming over a
decade after the species’ discovery and description, as a presumed non-native, in the SW Netherlands. Further morphological details of the species and notes on variation between individuals are provided. It seems probable that records of Bispira fabricii in Le Havre commencing in 2010, and at other sites on the French north coast, also relate to B. polyomma. An apparent association with marinas and ports suggests roles for recreational boats and commercial shipping in the dispersal of this species
Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves
No full textThis study aimed to investigate the impact of changing environmental conditions on MMI ES in seagrasses and mangroves. We used data from satellite and biodiversity platforms combined with field data to explore the links between ecosystem pressures (habitat conversion, overexploitation, climate change), conditions (environmental quality, ecosystem attributes), and MMI ES (provisioning, regulation, cultural). Both seagrass and mangrove extents increased significantly since 2016. While sea surface temperature showed no significant annual variation, sea surface partial pressure CO2, height above sea level and pH presented significant changes. Among the environmental quality variables only silicate, PO4 and phytoplankton showed significant annual varying trends. The MMI food provisioning increased significantly, indicating overexploitation that needs urgent attention. MMI regulation and cultural ES did not show significant trends overtime. Our results show that MMI ES are affected by multiple factors and their interactions can be complex and non-linear. We identified key research gaps and suggested future directions for research. We also provided relevant data that can support future ES assessments
Change, what change?
Get PDFThe title of this paper is the title of a presentation that I gave on 18th March 2023 at the Porcupine Marine Natural History Society conference ‘Waves of Change’. The title was provocative, and participants may have assumed that it was going to be a presentation that denied change. In fact, the talk illustrated different sorts of change, and lack of change, that had been recorded in marine habitats. Here, I put types of change into the context of reporting the ‘State of our Seas’ – something that the South-West Marine Ecosystems (SWME) webinars, conferences and reports have been describing since 201
A data-driven approach to flag land-affected signals in satellite derived water quality from small lakes
Get PDFThe land-affected signal in remotely sensed radiance from nearshore waters is a common problem for remote sensing, introducing uncertainty in atmospheric correction and subsequent water quality constituent concentration estimates. This study proposes a new method for identifying effects of land on satellite remote sensing of water quality. The new optical water types (OWT) containing the land-affected signal were derived from POLYMER-corrected imagery of the Medium Resolution Imaging Spectrometer in reduced resolution (MERIS RR) and Sentinel-3 Ocean and Land Colour Instrument (OLCI). These were then applied, as part of a larger set of existing OWTs corresponding to the variability observed in natural waters, to satellite images. The ability to identify pixels containing both water and land, and those contaminated with radiance from adjacent land, was evaluated. Our test sites include dark lakes of varying size in Sweden (Lakes Rusken, Bolmen, Ringsjon, ¨ and Ivosj ¨ on) ¨ where the classification showed high sensitivity to land near the lake shore. The land-affected signal is shown to lead to underestimations of chlorophyll-a concentration and Forel-Ule colour indices, and over estimations of turbidity in these lakes, which can be corrected after masking out the land-affected pixels. The
land-affected signal is strongest in summer, both NDVI and sun zenith angle covaried with the seasonal variation
of land-affected signal. Further, the results confirmed that satellite images with coarser spatial resolution are more prone to land-affected signal compared to images with finer spatial resolution, for small inland water bodies. We propose a data-driven approach for water quality processing with ‘land-affected water types’ as an effective way to improve the lake optical water quality monitoring from water colour sensors
Errata and re-visitation of “What is the limit for photoautotrophic plankton growth rates?” (Flynn and Raven, 2017)
Get PDFAn error in our original work prompts a revisitation of factors constraining photoautotrophic plankton growth rates (μmax). Ribulose-1,5-bisphosphate Carboxylase-Oxygenase does not itself provide that constraint, but we identify other factors that result in our previously suggested value of ~2 doublings per day still likely being representative of the maximum for most photoautotrophs. μmax likely evolves to balance the advantage of possessing a high competitive value while minimizing the stresses incurred when the organism is incapable of routinely achieving a higher μmax due to various limiting factors. Organisms with extreme high μmax are thus expected to grow under conditions that provide the necessary environment (stable pH, non-limiting nutrients and light) for sufficient time that the evolution of higher μmax becomes advantageous. Conditions in nature allowing the evolution of higher μmax include the exploitation of an exceptional opportunity and then entering stasis (e.g. desert microalgae), or a situation where high grazing pressures match high phytoplankton growth, thus maintaining non-limiting nutrient and light conditions. The latter, however, conflicts with the paradox of enrichment, as only under resource limitation would the necessary stability be attained in the predator–prey dynamic. Ultimately, ecology, not biophysics, constrains phototroph μmax
Field assessment of the potential for small scale co-cultivation of seaweed and shellfish to regulate nutrients and plankton dynamics
Get PDFThe co-cultivation of seaweed alongside shellfish has the potential to regulate local dissolved nutrient concentrations and consequently affect plankton dynamics. Evidence for this has until now come largely from computational modelling and laboratory studies, rather than field studies. Here we report on weekly/bi-weekly profiling of inorganic nutrient concentrations (nitrate, nitrite, ammonium, phosphate, and silicate) over two years (2019–2020) at three sampling stations across a small-scale (16 ha) kelp and mussel farm in Porthallow Bay, Cornwall, UK. Nutrient concentrations were measured in conjunction with a range of related environmental variables, including water temperature, salinity, clarity, and phyto- and zoo- plankton abundance, biomass and community composition. These environmental data were also supplemented with river discharge data. Our results indicate typical seasonal variations in chemical (nutrient), physical (hydrographic), and biological (plankton) parameters across all three sampling stations and no significant reductions in inorganic nutrient concentrations in the water column downstream from the integrated kelp and shellfish farm. We conclude that the effectiveness of nutrient regulation by integrating seaweed and shellfish aquaculture will depend on local climatic and hydro-geochemical conditions (affecting background nutrient inputs), as well as the design and scale of integrated multi–trophic aquaculture (IMTA) systems
Gephyrocapsa huxleyi (Emiliania huxleyi) as a model system for coccolithophore biology
Get PDFCoccolithophores are the most abundant calcifying organisms in modern oceans and are important primary producers in many marine ecosystems. Their ability to generate a cellular covering of calcium carbonate plates (coccoliths) plays a major role in marine biogeochemistry and the global carbon cycle. Coccolithophores also play an important role in sulfur cycling through the production of the climate-active gas dimethyl sulfide. The primary model organism for coccolithophore research is Emiliania huxleyi, now named Gephyrocapsa huxleyi. G. huxleyi has a cosmopolitan distribution, occupying coastal and oceanic environments across the globe, and is the most abundant coccolithophore in modern oceans. Research in G. huxleyi has identified many aspects of coccolithophore biology, from cell biology to ecological interactions. In this perspective, we summarize the key advances made using G. huxleyi and examine the emerging tools for research in this model organism. We discuss the key steps that need to be taken by the research community to advance G. huxleyi as a model organism and the suitability of other species as models for specific aspects of coccolithophore biology
Selection for antimicrobial resistance in the plastisphere
Get PDFMicroplastics and antimicrobials are widespread contaminants that threaten global systems and frequently co-exist in the presence of human or animal pathogens. Whilst the impact of each of these contaminants has been studied in isolation, the influence of this co-occurrence in driving antimicrobial resistance (AMR)1 in microplastic-adhered microbial communities, known as ‘the Plastisphere’, is not well understood. This review proposes the mechanisms by which interactions between antimicrobials and microplastics may drive selection for AMR in the Plastisphere. These include: 1) increased rates of horizontal gene transfer in the Plastisphere compared with free-living counterparts and natural substrate controls due to the proximity of cells, co�occurrence of environmental microplastics with AMR selective compounds and the sequestering of extracellular antibiotic resistance genes in the biofilm matrix. 2) An elevated AMR selection pressure in the Plastisphere due to the adsorbing of AMR selective or co-selective compounds to microplastics at concentrations greater than those found in surrounding mediums and potentially those adsorbed to comparator particles. 3) AMR selection pressure may be further elevated in the Plastisphere due to the incorporation of antimicrobial or AMR co-selective chemicals in the plastic matrix during manufacture. Implications for both ecological functioning and environmental risk assessments are discussed, alongside recommendations for further research
Methane Source Attribution in the UK Using Multi‐Year Records of CH4 and δ13C
Get PDFIsotopic measurements of atmospheric methane are valuable for the verification of bottom-up atmospheric emissions inventories. The balance of sources in emissions inventories must be consistent with the δ13C-CH4 isotopic record in the air. Long-term records of both methane mole fraction and δ13C from five sites across the UK are presented, showing post-2007 growth in CH4 and negative trend in δ13C, consistent
with global background sites. Miller-Tans analyses of atmospheric measurements identified that the δ13C signature of the methane source mix varied between −50.1 and −56.1‰, with less depleted δ13C signatures at sites receiving air from urban areas, consistent with an increased proportion of thermogenic sources. Isotopic signatures calculated for all sites are more enriched than those expected from the bottom-up emissions
inventory, suggesting that inventories for the UK either underestimate contributions of thermogenic/pyrogenic
emissions or overestimate biogenic sources
Spatial structure of in situ reflectance in coastal and inland waters: implications for satellite validation
Get PDFValidation of satellite-derived aquatic reflectance involves relating meter-scale in situ observations to satellite pixels with typical spatial resolution ∼ 10–100 m within a temporal “match-up window” of an overpass. Due to sub-pixel variation these discrepancies in measurement scale are a source of uncertainty in the validation result. Additionally, validation protocols and statistics do not normally account for spatial autocorrelation when pairing in situ data from moving platforms with satellite pixels. Here, using high-frequency autonomous mobile radiometers deployed on ships, we characterize the spatial structure of in situ Rrs in inland and coastal waters (Lake Balaton, Western English Channel, Tagus Estuary). Using variogram analysis, we partition Rrs variability into spatial and intrinsic (non-spatial) components. We then demonstrate the capacity of mobile radiometers to spatially sample in situ Rrs within a temporal window broadly representative of satellite validation and provide spatial statistics to aid satellite validation practice. At a length scale typical of a medium resolution sensor (300 m) between 5% and 35% (median values across spectral bands and deployments) of the variation in in situ Rrs was due to spatial separation. This result illustrates the extent to which mobile radiometers can reduce validation uncertainty due to spatial discrepancy via sub-pixel sampling. The length scale at which in situ Rrs became spatially decorrelated ranged from ∼ 100–1,000 m. This information serves as a guideline for selection of spatially independent in situ Rrs when matching with a satellite image, emphasizing the need for either downsampling or using modified statistics when selecting data to validate high resolution sensors (sub 100 m pixel size)