Resistance of seagrass habitats to ocean acidification via altered interactions in a tri-trophic chain

Despite the wide knowledge about prevalent effects of ocean acidification on single species, the consequences on species interactions that may promote or prevent habitat shifts are still poorly understood. Using natural CO2 vents, we investigated changes in a key tri-trophic chain embedded within all its natural complexity in seagrass systems. We found that seagrass habitats remain stable at vents despite the changes in their tri-trophic components. Under high pCO2, the feeding of a key herbivore (sea urchin) on a less palatable seagrass and its associated epiphytes decreased, whereas the feeding on higher-palatable green algae increased. We also observed a doubled density of a predatory wrasse under acidified conditions. Bottom-up CO2 effects interact with top-down control by predators to maintain the abundance of sea urchin populations under ambient and acidified conditions. The weakened urchin herbivory on a seagrass that was subjected to an intense fish herbivory at vents compensates the overall herbivory pressure on the habitat-forming seagrass. Overall plasticity of the studied system components may contribute to prevent habitat loss and to stabilize the system under acidified conditions. Thus, preserving the network of species interactions in seagrass ecosystems may help to minimize the impacts of ocean acidification in near-future oceans.The research was funded by an ASSEMBLE access project within the EU FP7/2007–2013 program (grant agreement n° 227799) hosted by MCG at the SZN. The Portuguese FCT– Fundação para a Ciência e a Tecnologia funded BMC in the ambit of the contract program DL57/2016/CP1361/CT0004 and CCMAR through the project UID/Multi/04326/2019.info:eu-repo/semantics/publishedVersio

Energy metabolism and cellular homeostasis trade-offs provide the basis for a new type of sensitivity to ocean acidification in a marine polychaete at a high-CO2 vent: adenylate and phosphagen energy pools versus carbonic anhydrase

Species distributions and ecology can often be explained by their physiological sensitivity to environmental conditions. Whilst we have a relatively good understanding of how these are shaped by temperature, for other emerging drivers, such as PCO2 we know relatively little. The marine polychaete Sabella spallanzanii increases its metabolic rate when exposed to high PCO2 conditions and remains absent from the CO2 vent of Ischia. To understand new possible pathways of sensitivity to CO2 in marine ectotherms, we examined the metabolic plasticity of S. spallanzanii exposed in situ to elevated PCO2 by measuring fundamental metabolite and carbonic anhydrase concentrations. We show that whilst this species can survive elevated PCO2 conditions in the short term, and exhibits an increase in energy metabolism, this is accompanied by a significant decrease in carbonic anhydrase concentration. These homeostatic changes are unlikely to be sustainable in the longer term, indicating S. spallanzanii may struggle with future high PCO2 conditions. -- Keywords : Individual approach ; PCO2 ; Climate change ; Homeostatic capacity ; Annelid ; Mediterranean Sea

Wind and shipping influences on sea currents around an inshore fish farm in a heavily contested Mediterranean embayment

Marine aquaculture expansion will continue to be challenged by a lack of space in areas of the marine domain that can support aquaculture, due to competition from other maritime activities vying for the same spaces. This research attempts to characterise those natural and anthropogenic forces that influence and drive sea currents measured over a 16-month period around a nearshore fish farm located within a busy multiple-use bay in the central Mediterranean Sea. Evidence from a concomitant two-year-long meteorological dataset reveals the occurrence of variable winds that result in a dominant and perpetual forcing on near-surface current magnitude and direction. The correlation coefficient between wind and sea currents decreases with increasing depth and hourly time lag. Moreover, the observed water level variations were more related to meteorological forcing factors than to tidal influences recorded at the mouth of the bay. However, intermittently observed water current values could not be exclusively explained by atmospheric forcing variables when the relationship between in-situ measurements and sea current values predicted by the hydrodynamic-wave model (Marine Forecasting System) was analysed. Consequently, this lack of correlation spurred further analysis, which revealed that relevant water current disturbances, particularly in near-surface sea currents, corresponded to 131 different Automatic Identification System (AIS) records of vessels. These vessels included bunkering barges, pilot boats and dredging vessels operating and navigating within a 650 m radius from the fish farm and during a 10-min window. This study thus provides evidence for natural and anthropogenically-derived influences on local fish farm-scale hydrodynamics that have important implications for the effective and sustainable development of aquaculture within a marine spatial context, especially in congested, multi-use environments

Final report of the short-term contract for ICCAT SMYTP for the biological samples collection for growth, maturity and genetics studies – Year #3

This document is the final report of the third year of the short-term contract of the Small Tuna Year Program by ICCAT, with the objectives of: a) conduct additional sampling aiming to fill the specific gaps of the biological samples for estimating the growth and maturity parameters for BON and LTA; b) estimate the referred parameters for both species, and preliminary provide preliminary results for WAH; and, c) refine the sampling and stock structure analysis for BON, LTA and WAH. A total of 374 individuals were collected: 145 of BON, 139 of LTA and 90 WAH. Initial target size class was accomplished only for BON in the Mediterranean. Small individuals are need in the Northeast and no samples were obtained in Southeast Atlantic. For LTA, total target sizes were not completely achieved in any case. However, preliminary results were obtained for growth and reproductive parameters. For BON, with samples arrived from Morocco, no genetic differentiation was detected, and the hypothesis provided in the previous contract is maintained. The population genetic analysis of WAH presents a scenario of homogeneous distribution.En prensa

The essentials of marine biotechnology.

Coastal countries have traditionally relied on the existing marine resources (e.g., fishing, food, transport, recreation, and tourism) as well as tried to support new economic endeavors (ocean energy, desalination for water supply, and seabed mining). Modern societies and lifestyle resulted in an increased demand for dietary diversity, better health and well-being, new biomedicines, natural cosmeceuticals, environmental conservation, and sustainable energy sources. These societal needs stimulated the interest of researchers on the diverse and underexplored marine environments as promising and sustainable sources of biomolecules and biomass, and they are addressed by the emerging field of marine (blue) biotechnology. Blue biotechnology provides opportunities for a wide range of initiatives of commercial interest for the pharmaceutical, biomedical, cosmetic, nutraceutical, food, feed, agricultural, and related industries. This article synthesizes the essence, opportunities, responsibilities, and challenges encountered in marine biotechnology and outlines the attainment and valorization of directly derived or bio-inspired products from marine organisms. First, the concept of bioeconomy is introduced. Then, the diversity of marine bioresources including an overview of the most prominent marine organisms and their potential for biotechnological uses are described. This is followed by introducing methodologies for exploration of these resources and the main use case scenarios in energy, food and feed, agronomy, bioremediation and climate change, cosmeceuticals, bio-inspired materials, healthcare, and well-being sectors. The key aspects in the fields of legislation and funding are provided, with the emphasis on the importance of communication and stakeholder engagement at all levels of biotechnology development. Finally, vital overarching concepts, such as the quadruple helix and Responsible Research and Innovation principle are highlighted as important to follow within the marine biotechnology field. The authors of this review are collaborating under the European Commission-funded Cooperation in Science and Technology (COST) Action Ocean4Biotech – European transdisciplinary networking platform for marine biotechnology and focus the study on the European state of affairs

Metabolic responses to high pCO2 conditions at a CO2 vent site in juveniles of a marine isopod species assemblage

We are starting to understand the relationship between metabolic rate responses and species' ability to respond to exposure to high pCO2. However, most of our knowledge has come from investigations of single species. The examination of metabolic responses of closely related species with differing distributions around natural elevated CO2 areas may be useful to inform our understanding of their adaptive significance. Furthermore, little is known about the physiological responses of marine invertebrate juveniles to high pCO2, despite the fact they are known to be sensitive to other stressors, often acting as bottlenecks for future species success. We conducted an in situ transplant experiment using juveniles of isopods found living inside and around a high pCO2 vent (Ischia, Italy): the CO2 'tolerant' Dynamene bifida and 'sensitive' Cymodoce truncata and Dynamene torelliae. This allowed us to test for any generality of the hypothesis that pCO2 sensitive marine invertebrates may be those that experience trade-offs between energy metabolism and cellular homoeostasis under high pCO2 conditions. Both sensitive species were able to maintain their energy metabolism under high pCO2 conditions, but in C. truncata this may occur at the expense of [carbonic anhydrase], confirming our hypothesis. By comparison, the tolerant D. bifida appeared metabolically well adapted to high pCO2, being able to upregulate ATP production without recourse to anaerobiosis. These isopods are important keystone species; however, given they differ in their metabolic responses to future pCO2, shifts in the structure of the marine ecosystems they inhabit may be expected under future ocean acidification conditions

Culturing the sea cucumber Holothuria poli in open-water integrated multi-trophic aquaculture at a coastal Mediterranean fish farm

The survival and growth of the sea cucumber Holothuria poli were assessed during a 12-month field study when cultured at a commercial fish farm in Malta as part of an integrated multi-trophic aquaculture (IMTA) system. Sea cucumbers were cultured directly below a fish cage at 0 m, E0, at 10 m (E10) and 25 m (E25) distances from the cage and at two reference sites (R1 and R2) located over 800 m away from the fish farm. Mass mortalities were recorded at E0 within the first month of the study due to smothering by settled wastes. All individuals died at one of the reference sites, R1, by the end of the study. After deducting missing sea cucumbers, survival rates at E10 (23%) and E25 (33%) from the fish cage were similar to the remaining reference site (R2) (27%). Stocking density and physical disturbances to the sea cucumber cage setup were also probable cause for the low survival rates. The relative weight gain (RWG) and specific growth rates (SGR) of H. poli varied significantly between sites close to the fish farm and the reference site. The SGR of H. poli at E10 (0.18 ±0.02% day-1) and E25 (0.20 ±0.01% day-1) was positive over the whole study period while no average growth was recorded at the reference site (-0.04 ±0.07% day-1) over the same period. Differences in RWG and SGR were recorded throughout the study. The overall growth observed in H. poli by January was followed by a drop in growth rate across all sites and an increase in SGR at E25 in July. Slower growth rates were observed as water temperature approached 15 oC. The results indicated that the sediments near the commercial fish cage provided an enriched source of food that supported significantly better growth in H. poli. This suggests that H. poli in IMTA might have the potential to uptake organic farm waste and increase aquaculture production, albeit with important considerations for setup design and stocking density

Proteomic profiles of Platynereis spp. collected from inside and outside the CO2 vent (Ischia, Italy) and used in a reciprocal transplant experiment in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) (stations A1-A3) or outside (40°43'33.33"N, 13°57'36.38"E and 40°44′48″N, 13°56′39″E) (stations C1-C3) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the proteome of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. This experiment was conducted between 04/09/2013 and 16/09/2013. The experiment was staggered during this time so all worms could be processed. After five days exposure to either low or high CO2 conditions worms were snap frozen in liquid nitrogen and shipped to the University of Hong Kong for proteomic analysis which was finalised on 02/08/2015. Proteomic profiles of worms were characterised using a liquid chromatography-mass spectrometry/mass spectrometry triple time of flight (LC-MS/ MS Triple TOF) approach

Environmental conditions inside and outside the CO2 vent (Ischia, Italy) before and during a reciprocal transplant experiment with Platynereis spp. in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) (stations A1-A3) or outside (40°43'33.33"N, 13°57'36.38"E and 40°44′48″N, 13°56′39″E) (stations C1-C3) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment between 04/09/2013 and 16/09/2013. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the proteome and metabolome (metabolome, and lipidome) of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. Before and during the transplant experiment water samples were taken to characterise the physio-chemical parameters of sea water used when exposing the worms to: (i) low pCO2 conditions (‘control’ stations C1, C2 and C3) and (ii) high pCO2 conditions (‘acidified’ stations A1, A2, A3). Salinity, temperature, pH NBS (Mettler-Toledo pH meter, Beaumont Leys, UK), total alkalinity (TA) (AS-ALK2, Apollo SciTech, Bogart, USA), dissolved inorganic carbon (DIC), carbon dioxide partial pressure (pCO2), bicarbonate and carbonate ion concentration ([HCO3–] and [CO32–), calcite and aragonite saturation state (Ωcal and Ωara) are provided

Metabolomic profiles of Platynereis spp. collected from inside and outside the CO2 vent (Ischia, Italy) and used in a reciprocal transplant experiment in September 2013

Platynereis spp. were collected via snorkelling or scuba from either inside (40°43′53″N, 13°57′47″E) or outside (40°43'33.33N, 13°57'36.38E and 40°44′48″N, 13°56′39″E) the carbon dioxide (CO2) vent on the island of Ischia (Italy) and used in a reciprocal transplant experiment. The effect of exposure to high or low partial pressures of CO2 (pCO2) conditions on the metabolome (metabolome, and lipidome) of worms from different pCO2 regimes was investigated to understand the effect of exposure to different pCO2 conditions on the cellular physiological response. This experiment was conducted between 04/09/2013 and 16/09/2013. The experiment was staggered during this time so all worms could be processed. After five days exposure to either low or high CO2 conditions worms were snap frozen in liquid nitrogen and shipped to the University of Birmingham for metabolomic analysis which was finalised on 21/01/2016. Metabolomic profiles of worms were characterised using a mass spectrometry approach. A standard mass spectrometry based metabolomics workflow was used to analyse both the polar and lipid extracts from the samples (Kirwan et al. 2014). Raw mass spectral data were processed using the SIM-stitching algorithm, using an in-house Matlab script. The data matrices were normalized using the PQN algorithm. Missing values were imputed using the KNN algorithm. The resulting data matrix was analysed using univariate statistics, described below. The same matrix was transformed using the generalised logarithm to stabilise the technical variance across the measured peaks prior to analysis using multivariate statistics. Signals were putatively annotated with empirical formulae calculated by the MIPack software (Weber et al. 2010), searching the KEGG (Kanehisa et al. 2012) and LipidMaps (Fahy et al. 2007) databases, and confirmed by performing calculations based on the original spectra in Xcalibur 2.0.7 (Thermo Fisher Scientific)