Recovering Wasted Nutrients From Shrimp Farming Through the Combined Culture of Polychaetes and Halophytes

[Abstract] The bioremediation and biomass production of organic extractive organisms (polychaetes Arenicola marina, Hediste diversicolor and halophyte Salicornia ramosissima) was assessed in an integrated multi-trophic aquaculture (IMTA) framework. Culture trials were performed outdoors using the nutient rich effluent from a shrimp farm employing recirculated aquaculture systems. Similar bioremediation efficiencies were obtained in cultures using a single polyculture tank (1 T) or two trophic levels separated tanks (2 T; ≈ 0.3 and 0.6 m2 operational area, respectively), with a reduction of 74–87% for particulate organic matter (POM), 56–64% for dissolved inorganic nitrogen (DIN) and 60–65% for dissolved inorganic phosphorus (DIP). Hediste diversicolor adapted well to culture conditions, reaching densities up to 5.000 ind. m−2 (≈ 78–98 g m−2). Arenicola marina failed to cope with water temperature that exceeded the species thermal limits, displaying a survival < 10% (20 °C often pointed as the maximum thermal threshold for this species). Productivity of S. ramosissima with 1 T was about twice that obtained with 2 T (≈ 150–170 and ≈ 60–90 g FW m−2 edible aboveground biomass, respectively). The yellowish coloration of cultured plants was likely due to the chemical oxidation and rapid sand filtration pre-treatment applied to the brackish groundwater used in the aquaculture facility, that removed iron (and probably other essential elements). Overall, 1 T design combining H. diversicolor and S. ramosissima displayed the best bioremediation performance and biomass production, while also allowing reducing in half the operational area required to implement this IMTA framework.European Commission; 24517, 10/SI/2016European Commission; MAR-02.01.01-FEAMP-0038European Commission; Centro-01-0145-FEDER-000018Fundação para a Ciência e a Tecnologia (Portugal); PD/BD/127989/2016Fundação para a Ciência e a Tecnologia (Portugal); CEECIND/01434/2018Fundação para a Ciência e a Tecnologia (Portugal); UIDP/50017/2020+UIDB/50017/202

Biology and ecology of the white prawn Palaemon longirostris H. Milne Edwards, 1837 (Crustacea, Decapoda, Palaemonidae) in the Mira River, Portugal

Tese de doutoramento, Biologia (Ecografia), Universidade de Lisboa, Faculdade de Ciências, 2014The white prawn, Palaemon longirostris H.-M. Edwards, 1837, is a shallow-water species, spread over a wide geographical area. Has been recorded in estuaries from the north of Africa up to western Germany and northeast of England and more recently its presence was registered for the Black Sea. Authors have disagreed on the taxonomic status of the white prawns over their distributional range that has been identified either as Palaemon longirostris and P.garciacidi. The present study compares variation in morphology and mtDNA in populations from the United Kingdom, the Netherlands, France, Spain, Portugal, Morocco and Tunisia. Findings from this study do not support the distinction of P.longirostris and P.garciacidi as different species. This study also aims at contributing to the knowledge of the bioecology of the prawn P.longirostris. The estuarine distribution of prawns of the River Mira population follow the salinity displacement, the animals being found at river stations during summer and autumn when saline encroachment up the estuary was greater. During winter and spring when freshwater input from the river was greatest, and thus moving the salinity gradient toward the mouth, the prawns migrated downstream to brackish areas. Ovigerous females were collected only from estuarine areas (January to August), suggesting that these population displacements are related to reproduction that does not take place in freshwater habitats. The reproductive period varies among the populations along their distributional range, starting earlier and being longer in the southern estuaries, probably due to the water higher temperature. The reproductive traits, fecundity, egg loss and size at maturity of female P.longirostris were also examined in this study. The growth was also studied for the Mira River population. This work contributes to a better understanding of morphological variation, migration patterns, reproduction and growth of P.longirostris, which can be used to implement a management and conservation measures that still lacking. It is urgent to develop management measures for the protection of the white shrimp, P.longirostris in estuaries and rivers over their distributional range, and the first efforts to be made should focus on habitat preservation and its rehabilitation by reinstating, for example, the longitudinal continuity of rivers allowing the reproductive migrations to take place.Fundação para a Ciência e a tecnologia, IP (FCT

Regulation of intertidal microphytobenthos photosynthesis over a diel emersion period is strongly affected by diatom migration patterns

Changes in biomass and photosynthesis of a diatom-dominated microphytobenthos (MPB) intertidal community were studied over a diel emersion period using a combination of O(2) and scalar irradiance microprofiling, variable chlorophyll (Chl) fluorescence, and pigment analysis. The MPB biomass in the photic zone (0–0.5 mm) of the sediment exposed to low irradiance (150 μmol photons m(-2) s(-1)) showed a >2-fold increase during the first hours of the emersion period, reaching >0.2 mg Chl a cm(-3). Concentrations of Chl a started to decrease half-way through the emersion period, almost 2 h before tidal inundation. Similarly, O(2) concentrations and volumetric gross photosynthesis in the photic zone increased during the first half of the emersion period and then decreased toward the timing of incoming tide/darkness. The results suggest that intertidal MPB community-level photosynthesis is mainly controlled by changes in the productive biomass of the photic zone determined by cell migration. A diel pattern in the photosynthesis vs. irradiance parameters α (photosynthetic efficiency at limiting irradiance) and ETR(max) (photosynthetic capacity at saturating irradiance) was also observed, suggesting photoacclimation of MPB. Under high light exposure (2000 μmol photons m(-2) s(-1)), lower α, ETR(max) and sediment O(2) concentrations were observed when cell migration was inhibited with the diatom motility inhibitor latrunculin A (Lat A), showing that migration is also used by MPB to maximize photosynthesis by reducing exposure to potentially photoinhibitory light levels. A higher de-epoxidation state in sediment treated with Lat A indicates that the involvement of the xanthophyll cycle in physiological photoprotection is more relevant in MPB when cells are inhibited from migrating. In the studied diatom-dominated MPB intertidal community, cell migration seems to be the key factor regulating photosynthesis over a diel emersion period and upon changes in light exposure

Milestone 3.2 - DiSSCo Digital Maturity Self -Assessment Tool - Design Blueprint

This Milestone 3.2 report for DiSSCo Prepare Work Package 3 Task 3.1 sets out the initial design blueprint for a DiSSCo Digital Maturity Self-Assessment Tool, building on the analyses in the Milestone 3.1 report ‘Improving Digital Capability - Case Studies and Analysis’ (Hardy et al, Dec 2020) and in the Milestone 3.3. Report, including consideration of two existing tools in our sector. This tool is intended to support teams, institutions and national nodes in developing organisational readiness for provision of the DiSSCo services and data, helping them to identify and target areas for improvement. The aim is for this to tie in to future provision of training and support, as well as helping to identify the gaps at aggregate level where that training may be most useful. In addition , we believe there is a case for a platform that can support both this and the related Task 7.3 Policy Tool, such that these or other tools are consistent for users and can interact with one another where relevant, avoiding any duplication. This blueprint is intended for wider discussion among the DiSSCo members, so that tool content can be developed in more detail as part of the Deliverable for this Taskinfo:eu-repo/semantics/publishedVersio

LED Lighting and High-Density Planting Enhance the Cost-Efficiency of Halimione Portulacoides Extraction Units for Integrated Aquaculture

Halophytes are salt-tolerant plants that can be used to extract dissolved inorganic nutrients from saline aquaculture effluents under a production framework commonly known as Integrated Multi-Trophic Aquaculture (IMTA). Halimione portulacoides (L.) Aellen (common name: sea purslane) is an edible saltmarsh halophyte traditionally consumed by humans living near coastal wetlands and is considered a promising extractive species for IMTA. To better understand its potential for IMTA applications, the present study investigates how artificial lighting and plant density affect its productivity and capacity to extract nitrogen and phosphorous in hydroponic conditions that mimic aquaculture effluents. Plant growth was unaffected by the type of artificial lighting employed—white fluorescent lights vs. blue-white LEDs—but LED systems were more energy-efficient, with a 17% reduction in light energy costs. Considering planting density, high-density units of 220 plants m−2 produced more biomass per unit of area (54.0–56.6 g m−2 day−1) than did low-density units (110 plants m−2; 34.4–37.1 g m−2 day−1) and extracted more dissolved inorganic nitrogen and phosphorus. Overall, H. portulacoides can be easily cultivated hydroponically using nutrient-rich saline effluents, where LEDs can be employed as an alternative to fluorescent lighting and high-density planting can promote higher yields and extraction efficienciesThe authors thank the Portuguese Foundation for Science and Technology (FCT) for the financial support to Marco Custódio (PD/BD/127990/2016), Paulo Cartaxana (CEECIND/01434/2018) and CESAM (UIDB/50017/2020+UIDP/50017/2020). This work was also supported by the Integrated Program of SR&TD “Smart Valorization of Endogenous Marine Biological Resources Under a Changing Climate” (reference Centro-01-0145-FEDER-000018), co-funded by Centro 2020 program, Portugal 2020 and European Union, through the European Regional Development Fund, and by the project “AquaMMIn—Development and validation of a modular integrated multitrophic aquaculture system for marine and brackish water species” (MAR-02.01.01-FEAMP-0038) co-funded by Portugal 2020 and the European Union through Mar 2020, the Operational Programme (OP) for the European Maritime and Fisheries Fund (EMFF) in PortugalS

Kleptoplast photoacclimation state modulates the photobehaviour of the solar-powered sea slug Elysia viridis.

Some sacoglossan sea slugs incorporate intracellular functional algal chloroplasts (kleptoplasty) for periods ranging from a few days to several months. Whether this association modulates the photobehaviour of solar-powered sea slugs is unknown. In this study, the long-term retention species Elysia viridis showed avoidance of dark independently of light acclimation state. On the contrary, Placida dendritica, which shows non-functional retention of kleptoplasts, showed no preference over dark, low or high light. High light acclimated (HLac) E. viridis showed a higher preference for high light than low light acclimated (LLac) conspecifics. The position of the lateral folds (parapodia) was modulated by irradiance, with increasing light levels leading to a closure of parapodia and protection of kleptoplasts from high light exposure. Furthermore, closure of parapodia occurred at higher irradiances in HLac E. viridis. Our results strongly indicate that kleptoplasts photoacclimation state modulates the photobehaviour of the solar-powered sea slug E. viridis

Photoinhibition in benthic diatom assemblages under light stress

Microphytobenthos are frequently subjected to light intensities higher than those required to saturate photosynthesis, which consequently can cause photoinhibition. Photosystem II (PSII) protein D1 (the main target of photoinhibition) and xanthophyll cycle pigments were quantified in epipelic benthic diatom assemblages under high irradiance, in the presence of inhibitors and promoters of photoprotection mechanisms. Levels of D1 protein were significantly lower under high irradiance (1 h, 1500 µmol photons m–2 s–1) than under low light (80 µmol photons m–2 s–1), corresponding to a photoinhibition of 22 to 29%. Photoinhibition increased to 44 and 80% in the presence of lincomycin (inhibitor of chloroplast-protein synthesis) and dithiothreitol (inhibitor of the xanthophyll cycle), respectively. High light treatment had no significant effect on D1 protein concentrations in the presence of added glutathione and ascorbate, scavengers of reactive oxygen species (ROS). In contrast, the ROS promoter methylviologen increased photoinhibition to 63%. Under light stress, the functional stability of PSII reaction centres of the studied epipelic benthic diatoms was more dependent on xanthophyll cycle activation than on D1 protein recycling mechanisms, and our results substantiate the role of antioxidants in photoprotection via ROS scavenging.publishe

Effects of elevated temperature and CO2 on intertidal microphytobenthos

Background: Microphytobenthos (MPB) are the main primary producers of many intertidal and shallow subtidal environments. Although these coastal ecosystems are particularly vulnerable to anthropogenic activities, little is known on the effects of climate change variables on the structure and productivity of MPB communities. In this study, the effects of elevated temperature and CO2 on intertidal MPB biomass, species composition and photosynthetic performance were studied using a flow-through experimental life support system. Results: Elevated temperature had a detrimental effect on MPB biomass and photosynthetic performance under both control and elevated CO2. Furthermore, elevated temperature led to an increase of cyanobacteria and a change in the relative abundance of major benthic diatom species present in the MPB community. The most abundant motile epipelic species Navicula spartinetensis and Gyrosigma acuminatum were in part replaced by tychoplanktonic species (Minidiscus chilensis and Thalassiosira cf. pseudonana) and the motile epipelic Nitzschia cf. aequorea and N. cf. aurariae. Elevated CO2 had a beneficial effect on MPB biomass, but only at the lower temperature. It is possible that elevated CO2 alleviated local depletion of dissolved inorganic carbon resulting from high cell abundance at the sediment photic layer. No significant effect of elevated CO2 was detected on the relative abundance of major groups of microalgae and benthic diatom species. Conclusions: The interactive effects of elevated temperature and CO2 may have an overall detrimental impact on the structure and productivity of intertidal MPB, and eventually in related ecosystem services