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Model projections show that production of high-value products from microalgae could be profitable nowadays and commodities will become profitable within 10 years.

Integrated multitrophic aquaculture (IMTA) is a versatile technology emerging as an ecological and sustainable solution for traditional monoculture aquacultures in terms of effluent treatment. Nevertheless, IMTA is still poorly applied in aquaculture industry due to, among other reasons, the lack of effective, low-investment and low-maintenance solutions. In this study, one has developed a practical and low maintenance IMTA-pilot system, settled in a semi-intensive coastal aquaculture. The optimisation and performance of the system was validated using Ulva spp., a macroalgae that naturally grows in the fishponds of the local aquaculture. Several cultivation experiments were performed at lab-scale and in the IMTA-pilot system, in static mode. The specific growth rate (SGR), yield, nutrient removal, N and C enrichment, protein and pigment content were monitored. Ulva spp. successfully thrived in effluent from the fish species sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) production tanks and significantly reduced inorganic nutrient load in the effluent, particularly, NH4+, PO43− and NO3−. The enrichment of nitrogen in Ulva spp.’s tissues indicated nitrogen assimilation by the algae, though, the cultivated Ulva spp. showed lower amounts of protein and pigments in comparison to the wild type. This study indicates that the designed IMTA-pilot system is an efficient solution for fish effluent treatment and Ulva spp., a suitable effluent remediator.

With respect to the ecological relevance of endpoints, biomass as an endpoint might be promising regarding ecotoxicological assessments of benthic communities. In a freshwater microcosm study the effect of two cadmium (Cd) concentrations (50 and 400 mg Cd kg(-1) dw) on biomass and abundance of a benthic community were investigated over a period of seven months. Specifically, the sensitivity of both endpoints in distinguishing differential effects was compared. While bacteria were found to be unaffected by Cd, abundance and biomass of protozoans and metazoans decreased. In a short-term comparison, differences between control and Cd treatments were, overall, more pronounced for flagellate biomass and for metazoan abundance with strong differences between the taxonomic groups; furthermore, over the long-term, the differences among organisms and endpoints changed. Based on toxicant sensitivity, the reasonably low variance of the data and the workload involved, biomass can provide a useful additional endpoint in microcosm studies.

A Bayesian network model was developed to assess the combined influence of nutrient conditions and climate on the occurrence of cyanobacterial blooms within lakes of diverse hydrology and nutrient supply. Physicochemical, biological, and meteorological observations were collated from 20 lakes located at different latitudes and characterized by a range of sizes and trophic states. Using these data, we built a Bayesian network to (1) analyze the sensitivity of cyanobacterial bloom development to different environmental factors and (2) determine the probability that cyanobacterial blooms would occur. Blooms were classified in three categories of hazard (low, moderate, and high) based on cell abundances. The most important factors determining cyanobacterial bloom occurrence were water temperature, nutrient availability, and the ratio of mixing depth to euphotic depth. The probability of cyanobacterial blooms was evaluated under different combinations of total phosphorus and water temperature. The Bayesian network was then applied to quantify the probability of blooms under a future climate warming scenario. The probability of the “high hazardous” category of cyanobacterial blooms increased 5% in response to either an increase in water temperature of 0.8°C (initial water temperature above 24°C) or an increase in total phosphorus from 0.01 mg/L to 0.02 mg/L. Mesotrophic lakes were particularly vulnerable to warming. Reducing nutrient concentrations counteracts the increased cyanobacterial risk associated with higher temperatures.

Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988–2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Following the lemming cycle collapse, snowy owl fledgling production declined by 98 per cent, and there was indication of a severe population decline of stoats at one site. The less specialized long-tailed skua and the generalist arctic fox were more loosely coupled to the lemming dynamics. Still, the lemming collapse had noticeable effects on their reproductive performance. Predator responses differed somewhat between sites in all species and could arise from site-specific differences in lemming dynamics, intra-guild interactions or subsidies from other resources. Nevertheless, population extinctions and community restructuring of this arctic endemic predator guild are likely if the lemming dynamics are maintained at the current non-cyclic, low-density state.

Harmful Algal Blooms (HAB) are complex to manage due to their intermittent nature and their severe impact on the economy and human health. The conditions which promote HAB have not yet been fully explained, though climate change and anthropogenic intervention are pointed as significant factors. The rise of water temperature, the opening of new sea canals and the introduction of ship ballast waters all contribute to the dispersion and establishment of toxin-producing invasive species that promote the settling of emergent toxins in the food-chain. Tetrodotoxin, ciguatoxin, palytoxin and cyclic imines are commonly reported in warm waters but have also caused poisoning incidents in temperate zones. There is evidence that monitoring for these toxins exclusively in bivalves is simplistic and underestimates the risk to public health, since new vectors have been reported for these toxins and as well for regulated toxins such as PSTs and DSTs. In order to avoid public health impacts, there is a need for adequate monitoring programs, a need for establishing appropriate legislation, and a need for optimizing effective methods of analysis. In this review, we will compile evidence concerning emergent marine toxins and provide data that may indicate the need to restructure the current monitoring programs of HAB.

Impact of drought under enriched CO2 atmosphere on ecophysiological and leaf metabolic response of the sub-mediterranean Q. pyrenaica oak was studied. Seedlings growing in climate chamber were submitted to moderate drought (WS) and well-watered (WW) under ambient ([CO2]amb =400 ppm) or CO2 enriched atmosphere ([CO2]enr =800 ppm). The moderate drought endured by seedlings brought about a decrease in leaf gas exchange. However, net photosynthesis (Anet) was highly stimulated for plants at [CO2]enr. There was a decrease of the stomatal conductance to water vapour (gwv) in response to drought, and a subtle trend to be lower under [CO2]enr. The consequence of these changes was an important increase in the intrinsic leaf water use efficiency (WUEi). The electron transport rate (ETR) was almost a 20 percent higher in plants at [CO2]enr regardless drought endured by seedlings. The ETR/Anet was lower under [CO2]enr, pointing to a high capacity to maintain sinks for the uptake of extra carbon in the atmosphere. Impact of drought on the leaf metabolome, as a whole, was more evident than that from [CO2] enrichment of the atmosphere. Changes in pool of non-structural carbohydrates were observed mainly as a consequence of water deficit including increases of fructose, glucose, and proto-quercitol. Most of the metabolites affected by drought back up to levels of non-stressed seedlings after rewetting (recovery phase). It can be concluded that carbon uptake was stimulated by [CO2]enr, even under the stomatal closure that accompanied moderate drought. In the last, there was a positive effect in intrinsic water use efficiency (WUEi), which was much more improved under [CO2]enr. Leaf metabolome was little responsible and some few metabolites changed mainly in response to drought, with little differences between [CO2] growth conditions.