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- Sex differences in oxidative stress responses of tropical topshells (Trochus histrio) to increased temperature and high pCO2Publication . F. Grilo, Tiago; Lopes, Ana Rita; Sampaio, Eduardo; Rosa, Rui; Cardoso, Patrícia G.Given scarcity of knowledge on gender ecophysiological responses of tropical marine organisms to global climate change, the major aim of this research was to investigate potential sex differences in oxidative status of topshell Trochus histrio, after a combined exposure to increased temperature and pCO2. Lipid peroxidation, heat-shock response and antioxidant enzymatic activities were evaluated. Lipid peroxidation varied differently between sexes, with males undergoing cellular damage under high pCO2, which was elevated temperature-counteracted. Heat shock response was thermo- and sex-regulated, with males exhibiting significantly higher heat shock proteins production than females. Catalase activity increased with temperature and was exacerbated in combination with hypercapnia, being highest in females, while glutathione S-transferases activity peaked in males. These results clearly support the existence of distinct physiological strategies to cope oxidative stress between sexes, apparently more efficient in females, and also reinforce for the need of encompassing sex as meaningful variable in future biomarker studies.
- Short-term effects of increased temperature and lowered pH on a temperate grazer-seaweed interaction (Littorina obtusata/Ascophyllum nodosum)Publication . Cardoso, Patricia G.; F. Grilo, Tiago; Dionísio, Gisela; Aurelio, Maria; Lopes, Ana Rita; Pereira, Ricardo; Pacheco, Mário; Rosa, RuiThere has been a significant increase in the literature regarding the effects of warming and acidification on the marine ecosystem. To our knowledge, there is very little information on the potential effects of both combined stressors on marine grazer-seaweed interactions. Here, we evaluated, for the first time several phenotypic responses (e.g periwinkle survival, condition index, consumption rates, seaweed photosynthetic activity and oxidative stress) of the temperate periwinkle Littorina obtusata (grazer) and the brown seaweed Ascophyllum nodosum (prey) to such climate change-related variables, for 15 days. Increased temperature (22 °C, pH 8.0) elicited a significant lethal effect on the periwinkle within a short-term period (mortality rate > 90%). Acidification condition (18 °C, pH 7.6) was the one that showed lower mortality rates (≈20%), reflected by lower impact on periwinkle fitness and consumption rates. Under a scenario of increased temperature and lowered pH the antioxidant defences of L. obtusata seemed to be supressed increasing the risk of peroxidative damage. The seaweed evidenced signs of cellular damage under such conditions. These results suggest that: i) lower pH per se seems to benefit the interaction between grazer and seaweed while, ii) a combined scenario of increased temperature and lowered pH may be negative for the interaction, due to the unbalance between periwinkle mortality rates and consumption rates. But most importantly, since grazing often plays an important role on structuring natural communities, such predator-prey disturbances can elicit cascading effects on the remaining community structure and functioning of the temperate rocky-shore ecosystems.
- Biological responses of sharks to ocean acidificationPublication . Rosa, Rui; Rummer, Jodie L.; Munday, Philip L.Sharks play a key role in the structure of marine food webs, but are facing major threats due to overfishing and habitat degradation. Although sharks are also assumed to be at relatively high risk from climate change due to a low intrinsic rate of population growth and slow rates of evolution, ocean acidification (OA) has not, until recently, been considered a direct threat. New studies have been evaluating the potential effects of end-of-century elevated CO2 levels on sharks and their relatives' early development, physiology and behaviour. Here, we review those findings and use a meta-analysis approach to quantify the overall direction and magnitude of biological responses to OA in the species of sharks that have been investigated to date. While embryo survival and development time are mostly unaffected by elevated CO2, there are clear effects on body condition, growth, aerobic potential and behaviour (e.g. lateralization, hunting and prey detection). Furthermore, studies to date suggest that the effects of OA could be as substantial as those due to warming in some species. A major limitation is that all past studies have involved relatively sedentary, benthic sharks that are capable of buccal ventilation-no studies have investigated pelagic sharks that depend on ram ventilation. Future research should focus on species with different life strategies (e.g. pelagic, ram ventilators), climate zones (e.g. polar regions), habitats (e.g. open ocean), and distinct phases of ontogeny in order to fully predict how OA and climate change will impact higher-order predators and therefore marine ecosystem dynamics.
- Presence and persistence of the amnesic shellfish poisoning toxin, domoic acid, in octopus and cuttlefish brainsPublication . Lopes, Vanessa M.; Rosa, Rui; Costa, Pedro R.Domoic acid (DA) is a neurotoxin that causes degenerative damage to brain cells and induces permanent short-term memory loss in mammals. In cephalopod mollusks, although DA is known to accumulate primarily in the digestive gland, there is no knowledge whether DA reaches their central nervous system. Here we report, for the first time, the presence of DA in brain tissue of the common octopus (Octopus vulgaris) and the European cuttlefish (Sepia officinalis), and its absence in the brains of several squid species (Loligo vulgaris, L. forbesi and Todarodes sagittatus). We argue that such species-specific differences are related to their different life strategies (benthic/nektobenthic vs pelagic) and feeding ecologies, as squids mainly feed on pelagic fish, which are less prone to accumulate phycotoxins. Additionally, the temporal persistence of DA in octopus' brain reinforces the notion that these invertebrates can selectively retain this phycotoxin. This study shows that two highly-developed invertebrate species, with a complex central nervous system, where glutamatergic transmission is involved in vertebrate-like long-term potentiation (LTP), have the ability of retaining and possibly tolerating chronic exposure to DA, a potent neurotoxin usually acting at AMPA/kainate-like receptors. Here, we filled a gap of information on whether cephalopods accumulated this neurotoxin in brain tissue, however, further studies are needed to determine if these organisms are neurally or behaviourally impaired by DA.
- Cuttlefish capsule: An effective shield against contaminants in the wildPublication . Rosa, Inês; Raimundo, Joana; Lopes, Vanessa; Brandão, Cláudio; Couto, Ana; Santos, Catarina; Cabecinhas, Adriana S.; Cereja, R; Calado, Ricardo; Caetano, Miguel; Rosa, RuiIncreasing anthropogenic pressures in estuaries are responsible for the rise of contaminants in several compartments of these ecosystems. Species that benefit from the nursery services provided by estuaries are exposed to such contaminants (e.g. metals and metalloids). It is therefore relevant to understand if marine invertebrates that use these areas as spawning grounds accumulate contaminants in their tissues throughout embryogenesis. This study aimed to quantify As, Co, Cr, Cu, Mn, Ni, Se, Pb, V and Zn concentrations in both capsule and embryos of the common cuttlefish (Sepia officinalis) in Sado Estuary (Portugal). Moreover, embryos at their initial, intermediate and final stage of development were collected in sites subjected to different anthropogenic pressures. In general, the capsule accumulated higher element concentration throughout embryogenesis which indicates that the capsule acts as an effective barrier against contaminants uptake by the embryo. Although the capsule becomes thinner throughout embryogenesis, embryo's protection does not seem to be compromised at later development stages. Additionally, the higher concentrations of As, Cu, Se and Zn in the embryo in comparison to the capsule suggests important biological roles during the embryogenesis of this cephalopod mollusc.
- Neuro-oxidative damage and aerobic potential loss of sharks under elevated CO2 and warmingPublication . Rosa, Rui; Paula, José Ricardo; Sampaio, Eduardo; Pimentel, Marta; Lopes, Ana Rita; Baptista, Miguel; Guerreiro, Miguel; Santos, Catarina; Campos, Derek; Almeida-Val, Vera M.F.; Calado, Ricardo; Diniz, Mário; Repolho, TiagoSharks occupy high trophic levels in marine habitats and play a key role in the structure and function of marine communities. Their populations have been declining worldwide by ≥90 %, and their adaptive potential to future ocean conditions is believed to be limiting. Here we experimentally exposed recently hatched bamboo shark (Chiloscyllium punctatum) to the combined effects of tropical ocean warming (+4; 30 °C) and acidification (ΔpH 0.5) and investigated the respiratory, neuronal and antioxidant enzymatic machinery responses. Thirty days post-hatching, juvenile sharks revealed a significant decrease in brain aerobic potential (citrate synthase activity), in opposition to the anaerobic capacity (lactate dehydrogenase). Also, an array of antioxidant enzymes (glutathione S-transferase, superoxide dismutase activity and catalase) acted in concert to detoxify ROS, but this significant upregulation was not enough to minimize the increase in brain’s peroxidative damage and cholinergic neurotransmission. We argue that the future conditions may elicit deleterious deficiencies in sharks’ critical biological processes which, at the long-term, may have detrimental cascading effects at population and ecosystem levels.
- Deficit in digestive capabilities of bamboo shark early stages under climate changePublication . Rosa, Rui; Pimentel, Marta; Galan, Juan; Baptista, Miguel; Lopes, Vanessa M.; Couto, Ana; Guerreiro, Miguel; Sampaio, Eduardo; Castro, Joana; Santos, Catarina; Calado, Ricardo; Repolho, TiagoLittle empirical information is currently available on the potential effects of acidification and/or warming in sharks, but none exist about digestive capabilities under such future conditions. Here, we investigated the impact of both acidification (ΔpH = 0.5) and warming (+4; 30 °C) on the digestive enzyme levels of recently hatched tropical bamboo shark (Chiloscyllium punctatum). Thirty days post-hatching, juvenile sharks revealed a significant increase in pancreatic trypsin levels under warming, but also a significant decrease under acidification, namely a 42 % drop under present-day temperature and 44 % drop under the warming condition. A similar trend was recorded for the alkaline phosphatase activity in shark’s intestine, i.e. the impact of environmental hypercapnia was also quite notorious—a 50 % drop under present-day temperature and 49 % drop under the warming condition. Thus, our present findings suggest that acidification and warming acted antagonistically, leading to similar enzyme activities under present and future conditions. Future directions on this topic of research should point towards the study of other types of sharks, namely pelagic ones with quite higher energetic demands.
- Symposium on “Climate Change and Molluscan Ecophysiology” at the 79th Annual Meeting of the American Malacological SocietyPublication . Marko, Peter B.; Carrington, Emily; Rosa, Rui; Giomi, Folco; Troschinski, Sandra; Melzner, Frank; Seibel, Brad A.Climate change has already had many observable effects on Earth. On land, glaciers and snowpacks have shrunk, tropical forests are being replaced by savannahs, and coastal areas have increased risks of flooding (e.g., IPCC 2007, Allan and Soden 2008, Dai 2010, NOAA 2010, Chen et al. 2011). In addition to sea-surface warming, climate change has altered the physical and chemical nature of the marine environment, including ocean acidification and expanding hypoxia. The scope and scale of future environmental change that individuals will undergo on land and in the sea will fundamentally influence the ecological and evolutionary responses of populations and species, dependent on their evolved physiological capacities for environmental tolerance (Parmesan 2006, Hoffmann and Sgrò 2011, Kuntner et al. 2014). Although climate change will affect all organisms, molluscs are unique in many respects, and, given their high diversity and evolutionarily flexible body plan, they provide several established and emerging models systems for comparative physiological study in nearly all types of ecosystems, from rivers to rocky shores and deserts to the deep sea. Moreover, many mollusks play pivotal roles as consumers, predators, and competitors in a diversity of ecosystems and habitats. Mollusks also have great economic importance, with many species of mollusks harvested by humans for food, either from natural populations or from aquaculture. The joint meeting of the American Malacological Society and the World Congress of Malacology in Ponta Delgada, Azores, on July 23rd 2013, brought together malacologists actively pursuing research aimed at addressing the direct and indirect impacts of climate change and the mechanisms mollusks use to compensate for these changes, their natural evolved tolerances, and the energetic, ecological, and biogeographic consequences of compensation. The goal for this symposium was to expose a broad range of malacologists to ecophysiological approaches in the hopes of recruiting and stimulating interest in the emerging questions of this field. Speakers included those whose talks addressed the effects of climate change on mollusks across a wide range of time scales and levels of biological organization, describing the results from recent research as well as considerations of some of the challenges facing ecophysiological research on mollusks in the future.
- Foraging behaviour, swimming performance and malformations of early stages of commercially important fishes under ocean acidification and warmingPublication . Pimentel, Marta; Faleiro, Filipa; Marques, Tiago; Bispo, Regina; Dionísio, Gisela; Faria, Ana M.; Machado, Jorge; Peck, Myron A.; Pörtner, Hans; Pousão-Ferreira, Pedro; Gonçalves, Emanuel J.; Rosa, RuiEarly life stages of many marine organisms are being challenged by climate change, but little is known about their capacity to tolerate future ocean conditions. Here we investigated a comprehensive set of biological responses of larvae of two commercially important teleost fishes, Sparus aurata (gilthead seabream) and Argyrosomus regius (meagre), after exposure to future predictions of ocean warming (+4 °C) and acidification (ΔpH = 0.5). The combined effect of warming and hypercapnia elicited a decrease in the hatching success (by 26.4 and 14.3 % for S. aurata and A. regius, respectively) and larval survival (by half) in both species. The length for newly-hatched larvae was not significantly affected, but a significant effect of hypercapnia was found on larval growth. However, while S. aurata growth was reduced (24.8–36.4 % lower), A. regius growth slightly increased (3.2–12.9 % higher) under such condition. Under acidification, larvae of both species spent less time swimming, and displayed reduced attack and capture rates of prey. The impact of warming on these behavioural traits was opposite but less evident. While not studied in A. regius, the incidence of body malformations in S. aurata larvae increased significantly (more than tripled) under warmer and hypercapnic conditions. These morphological impairments and behavioural changes are expected to affect larval performance and recruitment success, and further influence the abundance of fish stocks and the population structure of these commercially important fish species. However, given the pace of ocean climate change, it is important not to forget that species may have the opportunity to acclimate and adapt.
- Climate change impacts on the distribution of coastal lobstersPublication . Boavida-Portugal, Joana; Rosa, Rui; Calado, Ricardo; Pinto, Maria; Boavida-Portugal, Inês; Araújo, Miguel B.; Guilhaumon, FrançoisCoastal lobsters support important fisheries all over the world, but there is evidence that climate-induced changes may jeopardize some stocks. Here we present the first global forecasts of changes in coastal lobster species distribution under climate change, using an ensemble of ecological niche models (ENMs). Global changes in richness were projected for 125 coastal lobster species for the end of the century, using a stabilization scenario (4.5 RCP). We compared projected changes in diversity with lobster fisheries data and found that losses in suitable habitat for coastal lobster species were mainly projected in areas with high commercial fishing interest, with species projected to contract their climatic envelope between 40 and 100%. Higher losses of spiny lobsters are projected in the coasts of wider Caribbean/Brazil, eastern Africa and Indo-Pacific region, areas with several directed fisheries and aquacultures, while clawed lobsters are projected to shifts their envelope to northern latitudes likely affecting the North European, North American and Canadian fisheries. Fisheries represent an important resource for local and global economies and understanding how they might be affected by climate change scenarios is paramount when developing specific or regional management strategies.