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Estuaries are among the most valuable aquatic systems by their services to human welfare. However, increasing human activities at the watershed along with the pressure of climate change are fostering the co-occurrence of multiple environmental drivers, and warn of potential negative impacts on estuaries resources. At present, no clear understanding of how coastal ecosystems will respond to the non-stationary effect of multiple drivers. Here we analysed the temporal interaction among multiple environmental drivers and their changing priority on shaping phytoplankton response in the Bahía Blanca Estuary, SW Atlantic Ocean. The interaction among environmental drivers and the number of significant direct and indirect effects on chlorophyll concentration increased over time in concurrence with enhanced anthropogenic stress, changing winter climate and wind patterns. Over the period 1978-1993, proximal variables such as nutrients, water temperature and salinity, showed a dominant effect on chlorophyll, whereas in more recent years (1993-2009) climate signals (SAM and ENSO) boosted indirect effects through its influence on precipitation, wind, water temperature and turbidity. Turbidity emerged as the dominant driver of chlorophyll while in recent years acted synergistically with the concentration of dissolved nitrogen. As a result, chlorophyll concentration showed a significant negative trend and a loss of seasonal peaks reflecting a pronounced reorganisation of the phytoplankton community. We stress the need to account for the changing priority of drivers to understand, and eventually forecast, biological responses under projected scenarios of global anthropogenic change.

Available methods for measuring the impact of ocean acidification (OA) and leakage from carbon capture and storage (CCS) on marine sedimentary pH profiles are unsuitable for replicated experimental setups. To overcome this issue, a novel optical sensor application is presented, using off-the-shelf optode technology (MOPP). The application is validated using microprofiling, during a CCS leakage experiment, where the impact and recovery from a high CO2 plume was investigated in two types of natural marine sediment. MOPP offered user-friendliness, speed of data acquisition, robustness to sediment type, and large sediment depth range. This ensemble of characteristics overcomes many of the challenges found with other pH measuring methods, in OA and CCS research. The impact varied greatly between sediment types, depending on baseline pH variability and sediment permeability. Sedimentary pH profile recovery was quick, with profiles close to control conditions 24 h after the cessation of the leak. However, variability of pH within the finer sediment was still apparent 4 days into the recovery phase. Habitat characteristics need therefore to be considered, to truly disentangle high CO2 perturbation impacts on benthic systems. Impacts on natural communities depend not only on the pH gradient caused by perturbation, but also on other processes that outlive the perturbation, adding complexity to recovery.

Elevated environmental carbon dioxide (pCO2) levels have been found to cause organ damage in the early life stages of different commercial fish species, including Atlantic cod (Gadus morhua). To illuminate the underlying mechanisms causing pathologies in the intestines, the kidney, the pancreas and the liver in response to elevated pCO2, we examined related gene expression patterns in Atlantic cod reared for two months under three different pCO2 regimes: 380 μatm (control), 1800 μatm (medium) and 4200 μatm (high). We extracted RNA from whole fish sampled during the larval (32 dph) and early juvenile stage (46 dph) for relative expression analysis of 18 different genes related to essential metabolic pathways. At 32 dph, larvae subjected to the medium treatment displayed an up-regulation of genes mainly associated with fatty acid and glycogen synthesis (GYS2, 6PGL, ACoA, CPTA1, FAS and PPAR1b). Larvae exposed to the high pCO2 treatment upregulated fewer but similar genes (6PGL, ACoA and PPAR1b,). These data suggest stress-induced alterations in the lipid and fatty acid metabolism and a disrupted lipid homeostasis in larvae, providing a mechanistic link to the findings of lipid droplet overload in the liver and organ pathologies. At 46 dph, no significant differences in gene expression were detected, confirming a higher resilience of juveniles in comparison to larvae when exposed to elevated pCO2 up to 4200 μatm.

Myanmar's fisheries are among the most important globally but remain some of the least documented. The fisheries sector occupies an important place in Myanmar's economy and culture, and is set to change rapidly as the country enters a period of unprecedented political and economic transition. Building on a unique set of information sources, this article presents a broad view of the current state of knowledge on governance, livelihoods, production and supply chains across Myanmar's three main fishery sub-sectors (marine capture, inland capture, and aquaculture). The analysis is contextualized with a review of major changes in the country's policy history affecting fisheries. It is argued that Myanmar's fisheries now sit at a potential cross-road in terms of their governance. Taking advantage of Myanmar's latecomer position in its current transition, this article draws parallels with regional experiences to outline sectoral recommendations for policy reform.

Abstract Monitoring operations at the seafloor above a storage complex area are required to demonstrate that offshore storage of CO2 in the deep subsurface is safe and effective. Within the framework of the STEMM-CCS project, the Goldeneye area was identified as an offshore experimental site for CO2 storage. In this work, the physico-chemical characteristics of the water column at the Goldeneye site were determined by an in-depth analysis of measurements collated from CTD casts, discrete water samples and seafloor landers. The results showed a clear tidal, seasonal and inter-annual variability in the measured parameters within the monitoring period (Oct 2017- May 2019). Variations in pH and pCO2 over a single tidal cycle were in the order of ±0.008 and ±1.5 μatm, respectively. The temporal variability of water column carbonate chemistry parameters was further defined with the aim to provide a solid background for the discrimination from natural changes of potential impacts of CO2 emissions at the potential storage site. Here, we demonstrated how the combination of new and existing methods and technologies could be used for an effective assessment of water column conditions at a potential offshore carbon storage site.

Abstract Within the framework of the STEMM-CCS project, a controlled CO2 release experiment was conducted under real-life conditions in the Goldeneye complex area, a depleted gas field located in the UK sector of the North Sea. Here, the viability of water column monitoring for the detection of the injected CO2 is evaluated. Real-time pH and pCO2 measurements were taken in the water column during the CO2 release experiment. Monitoring was carried out throughout the full water column, from the near-seafloor to the sea surface, in order to assess the spatial extent of the CO2 release. The dispersion of the CO2 plume was strongly influenced by tidal circulation in the area. The strongest signals were detected within 8 m of the bubble stream during low tide. The lowest pH and highest pCO2 values were 7.965 and 942.1 µatm, respectively, corresponding to variations of 16.4% [H+] and 125.6% from baseline values. The pCO2 baseline dynamics of Goldeneye area were assessed by the evaluation of the natural pCO2-O2 covariance. The estimation of seasonal thresholds for anomalous pCO2 (pCO2:O2 ratio May= 1.63 ± 0.04) allowed us to assess with confidence the non-biological origin of the detected CO2 during the release experiment.

AbstractGiven the accelerating rate of biodiversity loss, the need to prioritize marine areas for protection represents a major conservation challenge. The three‐dimensionality of marine life and ecosystems is an inherent element of complexity for setting spatial conservation plans. Yet, the confidence of any recommendation largely depends on shifting climate, which triggers a global redistribution of biodiversity, suggesting the inclusion of time as a fourth dimension. Here, we developed a depth‐specific prioritization analysis to inform the design of protected areas, further including metrics of climate‐driven changes in the ocean. Climate change was captured in this analysis by considering the projected future distribution of >2000 benthic and pelagic species inhabiting the Mediterranean Sea, combined with climatic stability and heterogeneity metrics of the seascape. We identified important areas based on both biological and climatic criteria, where conservation focus should be given in priority when designing a three‐dimensional, climate‐smart protected area network. We detected spatially concise, conservation priority areas, distributed around the basin, that protected marine areas almost equally across all depth zones. Our approach highlights the importance of deep sea zones as priority areas to meet conservation targets for future marine biodiversity, while suggesting that spatial prioritization schemes, that focus on a static two‐dimensional distribution of biodiversity data, might fail to englobe both the vertical properties of species distributions and the fine and larger‐scale impacts associated with climate change.

Quantifying biotic feedbacks in response to environmental signals is fundamental to assess ecosystem perturbation. We analyzed the joint effects of eutrophication, derived from sewage pollution, and climate at the base of the pelagic food web in the Bahía Blanca Estuary (SW Atlantic Ocean). A two-year survey of environmental conditions and microplankton communities was conducted in two sites affected by contrasting anthropogenic eutrophication conditions. Under severe eutrophication, we found higher phytoplankton abundance consistently dominated by smaller sized, non siliceous species, while microzooplankton abundance remained lower and nutrient stoichiometry showed conspicuous deviations from the Redfield ratio. Phytoplankton growth in such conditions appeared controlled by phosphorous. In turn, microplankton biomass and phytoplankton size ratio (20μm) displayed a saturation relationship with nutrients in the highly eutrophic area, although mean phytoplankton growth was similar in both eutrophic systems. The strength of links within the estuarine network, quantified through path analysis, showed enhanced relationships under larger anthropogenic eutrophication, which fostered the climate influence on microplankton communities. Our results show conspicuous effects of severe sewage pollution on the ecological stoichiometry, i.e., N and P excess with respect to Si, altering nutrient ratios for microplankton communities. This warns on wide consequences on food web dynamics and ultimately in ecosystem assets of coastal pelagic environments.