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Integrating diverse marine predator data for robust species distribution models in a dynamic ocean
No full textSpecies distribution models (SDMs) are an important tool for marine conservation and management, yet guidance on leveraging diverse data to build robust models is limited. We evaluated whether an integrated SDM (iSDM) framework outperforms traditional data pooling or ensemble approaches when synthesizing multiple data types. We trained traditional SDMs and iSDMs using three data types for the blue shark (Prionace glauca) in the North Atlantic: fishery-dependent marker tags, observer records, and fishery-independent electronic tags. We compared pooled and ensembled SDMs, built with boosted regression trees, to an iSDM explicitly designed to address data-specific biases while leveraging each dataset’s strengths. While all approaches produced robust models, performance varied among data types, with fishery-dependent data consistently yielding more accurate than fishery-independent data. Differences in performance stemmed from models’ abilities to capture spatiotemporal dynamics in training data. iSDMs accounting for seasonal variability yielded the most accurate estimates but were computationally intensive, emphasizing the need to align model purpose with integration methods. Our findings reveal key trade-offs in data integration methods, particularly in balancing predictive accuracy and feasibility. As diverse data sources grow, leveraging robust approaches will be vital for improving conservation and management strategies and understanding dynamic species distributions in a changing ocea
A novel multispecies approach for the detection of regime shifts in a plankton community – a case study in the North Sea
No full texthe physical environment both above and below the ocean surface has changed dramatically during the last century. Changes in the marine environment induced by increased release of greenhouse gases and direct exploitation of resources include increased ocean temperature, decreased salinity and pH, and removal of apex predators. The risk of ecological regime shifts occurring has similarly increased. A variety of methodologies to identify regime shifts have already been used in the North Sea, which has become an important case study for the analysis of regime shifts in a semi-enclosed waterbody. The North Sea is regarded as a case study in part due to the operation of the continuous plankton recorder, which has provided detailed abundance records of phyto- and zooplankton for over 60 years. Here, we propose a new methodology to calculate regime shift likelihood for every month between 1958 and 2020. This unique model produces a single time series of regime shift likelihood, using sequential abundance data of more than 300 plankton species. We show the model's ability to identify when regime shifts occurred in the past by comparing it to previous less automated methodologies. We have validated the model for use in the North Sea by estimating how often false positives and false negatives are generated. Results from the model indicate evidence for three periods of high regime shift likelihood in various parts of the North Sea: between 1962 and 1972, between 1989 and 1999, and from 2002 until 2015. We show that these periods are consistent with previous estimates of North Sea regime shifts, and discuss possible applications of the model's output of a single time serie
Propagating uncertainty from physical and biogeochemical drivers through to top predators in dynamic Bayesian ecosystem models improves predictions
Full text linkWith the global rapid expansion of offshore renewable energies, there is an urgent need to assess and predict effects on marine species, habitats, and ecosystem functioning. Doing so will require dynamic, multitrophic, ecosystem-centric approaches coupled with oceanographic models that can allow for physical and/or biogeochemical indicators of marine ecosystem change to be included. However, in such coupled approaches, indicators carry uncertainties that can propagate and affect species higher up the trophic chain. Dynamic Bayesian networks (DBNs) are pragmatic approaches that probabilistically represent ecosystem-level interactions. They allow for uncertainties to be better estimated than mechanistic models that only account for expected values. In this study, we calculated variance as a measure of uncertainty from selected indicators and used them to build DBN models. A hidden variable was incorporated to model functional ecosystem change, where the underlying interactions dramatically change, following a disturbance. We wanted to assess whether propagating uncertainty into the modelling process affects the predictive accuracy of the models in the context of reconstructing the time series of the ecosystem dynamics. Model accuracy was improved for 60 % of the species once variance was added. The models were better in capturing the temporal inter-annual variability, once variance was calculated with a rolling window approach. The hidden variable successfully modelled previously identified ecosystem changes, however, now with the added uncertainty, the changes that implicated the ecosystem state were identified earlier in the time series. The results indicate that using DBNs is highly valuable as it gains accuracy with the addition of uncertainty
Abiotic Stress-Induced Chloroplast and Cytosolic Ca2+ Dynamics in the Green Alga Chlamydomonas reinhardtii
No full textCalcium (Ca2+)-dependent signalling plays a well-characterised role in the perception and response mechanisms to environmental stimuli in plant cells. In the context of a constantly changing environment, it is fundamental to understand how crop yield and microalgal biomass productivity are affected by external factors. Ca2+ signalling is known to be important in different physiological processes in microalgae but many of these signal transduction pathways still need to be characterised. Here, compartment-specific Ca2+ dynamics were monitored in Chlamydomonas reinhardtii cells in response to environmental stressors, such as nutrient availability, osmotic stress, temperature fluctuations and carbon sensing. An in vivo single-cell imaging approach was adopted to directly visualise changes of Ca2+ concentrations at the level of specific subcellular compartments, using C. reinhardtii lines expressing a genetically encoded ratiometric Ca2+ indicator. Hyper-osmotic shock caused cytosolic and chloroplast Ca2+ elevations, whereas high temperature and inorganic carbon availability primarily induced Ca2+ transients in the chloroplast. In contrast, hypo-osmotic stress only induced Ca2+ elevations in the cytosol. The results herein reported show that in Chlamydomonas cells compartment-specific Ca2+ transients are closely related to specific external environmental stimuli, providing useful guidance for studying signal transduction mechanisms exploited by microalgae to respond to specific natural condition
Microplastics in Antarctica - A plastic legacy in the Antarctic snow?
Full text linkMicroplastic pollution in remote inland Antarctica is largely unknown. This study explored the plastic footprint
of snow from remote Antarctic camps: Union Glacier, Schanz Glacier and the South Pole. Refined automated
FTIR techniques enabled interrogation of microplastics (including fibres) to a lower detection limit of 11 μm in
Antarctic snow for the first time. Microplastics were pervasive (73–3099 MP L− 1
). The majority (95 %) measured
<50 μm, indicating that previous microplastic reports in Antarctica may be underestimated, due to analytical
restrictions. Plastic polymer composition and concentration did not vary significantly between sites, with
dominant polymers being polyamide (PA), polyethylene terephthalate (PET), polyethylene (PE) and synthetic
rubber. Results indicate that even in the earth's most remote regions, humans are leaving a plastic legacy in the
snow, illustrating the importance of remote, cryospheric regions as critical study sites for determining temporal
fluxes in microplastic pollution
Brine Management to Increase CO2 Storage in Offshore Saline Aquifers: Practical Challenges
No full textAbstract
Carbon dioxide (CO2) storage capacity in saline aquifers is limited by the increase in reservoir pressure as CO2 is injected. Extraction of reservoir brine is an option to manage this pressure and maximize CO2 storage. In the UK North Sea, Endurance is the largest and best-appraised saline aquifer CO2 store. This paper assesses the option to extract brine from Endurance and substantially increase its storage potential. The focus is the management of this highly saline brine: discharge offshore, re-injection or treatment onshore?
Three main strands of work informed the assessment:
Quantification of the potential environmental impact of offshore discharge, via Whole Effluent Toxicity (WET) testing, flume tank experiments on dilution of surface and subsea brine discharges, changes in metal speciation and bioavailability during mixing and modelling of mineral precipitation, and modelling of brine discharge mixing with seawater using the Dose-related Risk and Effects Model (DREAM). Conceptual engineering and costing of the three main brine management options: offshore discharge, brine re-injection into a secondary reservoir, and onshore brine treatment. "Best Practicable Environmental Option" assessment, comparing the advantages and disadvantages of each of the potential brine management methods.
This paper highlights the complex balance between managing potential environmental impacts, stakeholder views and regulatory requirements, whilst delivering an economically efficient and technically robust brine management concept. Re-injection via nearby facilities ranks as the best option, eliminating any potential environmental impact caused by toxicity of the brine, although technical feasibility and safety risks are increased. Onshore treatment is a relatively lower cost option but requires an onward management and disposal of resultant waste streams following treatment that is unlikely to be an environmentally credible option. Offshore discharge is the lowest cost and most technically feasible option; however, potential environmental impact, along with reputational and regulatory risks, currently make this unattractive. This analysis underlines the additional risks from expanding carbon capture, use and storage (CCUS) projects to include brine management within their scope.
The study informed long-term development choices made for the Northern Endurance Partnership (NEP), resulting in acquisition of additional carbon storage licences to ensure sufficient CO2 storage capacity without the need for brine extraction. The environmental testing and modelling of brine discharge extends industry knowledge in a new and important area, as most of the future CO2 storage capacity in the UK North Sea resides in saline aquifers. Regulatory clarity on the toxicity assessment techniques and the constraints/limits to be imposed on any brine discharge is required for brine management to be considered within UK CCUS projects
Marine natural capital training materials
Full text linkSea the Value brings together a unique interdisciplinary team and international network of collaborators to address fundamental questions regarding the economics of biodiversity, specifically of blue carbon and marine water quality. The team includes internationally recognised expertise in environmental and ecological economics, marine
ecology, human geography, governance, and finance, putting us in an unrivalled position to make a transformative change. Our vision is to determine novel and policy
relevant pluralistic values for marine biodiversity and apply these values to co-develop green investment options, leading to a transformative shift in our understanding and
utilisation of the economics of biodiversity
Offshore wind energy: assessing trace element inputs and the risks for co-location of aquaculture
Full text linkCo-locating aquaculture with Offshore Wind Farms (OWFs) is a novel global energy sustainability policy driver. However, trace elements (TEs) from turbine corrosion-protection systems could generate significant ecosystem, economic, and human health risks. We calculate annual inputs for current European OWF capacity (30 GW) as: 3219 t aluminium, 1148 t zinc and 1.9 t indium, but these will increase ~12× by 2050, eclipsing known discharges. However, a paucity of industry data makes it impossible to compare water and sediment TE concentrations at operational OWFs against toxicity thresholds, therefore, ecotoxicological risks are under assessed. TE accumulation in seafood is a major human exposure route. Accumulated high tissue concentrations in oysters, mussels and kelp during co-location culture would contribute significantly to or greatly exceed (e.g. oyster zinc accumulation) an adult’s Tolerable Weekly Intake. We provide an industry/regulator ‘road map’ for implementing key policy changes to minimise unintended risks of rapid global OWF expansion
Foundation species loss alters algal community structure and dynamics at a trailing range edge
No full text1. Foundation species are the basis of entire ecosystems and are increasingly threatened by climate change. At trailing edges, population loss can be rapid as extreme warming events can exceed physiological thresholds, causing local extinctions where recruitment cannot sustain recovery. Whilst such losses can be projected, the impacts on remaining communities and potential recovery are difficult to predict, which limits our anticipatory power.
2. Here, we simulated the decline and loss of a cold-adapted marine foundation species (the kelp Laminaria digitata) at two trailing-edge sites, characterised by varying levels of wave exposure and L. digitata dominance. We first exposed macroalgal communities to a pulse disturbance (complete canopy removal) and then tracked trajectories of secondary succession for 2.5 years, under manipulated levels of recruitment (0%, 50% and 100% removal).
3. Background recruitment (0% removal) resulted in the development of assemblages similar to pre-disturbance levels, indicating a high degree of stability/resilience within the system. However, with increasing L. digitata removal, this resilience was lost, which led to decreased standing stock biomass of canopy-formers/understorey algae and clear shifts in assemblage structure.
4. Wave-exposed conditions caused a complete shift to a short-lived opportunistic species, which provided less stable and favourable habitat and supported distinct communities. Sheltered conditions caused more complex shifts towards multiple alternative canopy-formers.
5. Synthesis. These findings show the indirect effects of climate-driven population loss, through changes in ecological interactions such as competition, can propagate through entire communities. Given kelp underpin the wider temperate reef food web, this will likely have serious knock-on consequences at the ecosystem level