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  • Ocean acidification impacts on zooplankton
    Publication . Campoy, Ana N.; Cruz, Joana; Ramos, Joana Barcelos e; Viveiros, Fátima; Range, Pedro; Teodosio, M A; Teodósio, M. Alexandra; Barbosa, Ana B.
    Global change is and will continue impacting biodiversity, as many studies have already documented. Rising atmospheric CO2 is alleviated by oceanic uptake, since atmosphere and surface ocean exchange CO2 , but it also modifies the ocean carbonate system towards decreased carbonate ion concentrations and a corresponding decline in seawater pH. This process is known as ocean acidification (OA) and has a direct effect on plankton, namely calcifying organisms, such as coccolithophores, foraminifers, corals, molluscs and crustaceans, with consequences for the entire marine ecosystem (see review by Reibesell and Tortell 2011).
  • Larval hatching and development of the wedge shell (Donax trunculus L.) under increased CO2 in southern Portugal
    Publication . Pereira, Alexandre Miguel; Range, Pedro; Campoy, Ana; Oliveira, Ana Paula; Joaquim, Sandra; Matias, Domitília; Chícharo, Luís; Gaspar, Miguel
    Noticeable changes in global temperatures, climate and ocean carbon chemistry are the result of carbon dioxide increase in the atmosphere. This increase has been mitigated by the oceans capacity to absorb one-fourth of the carbon dioxide in the atmosphere, although this CO2 intake affects oceans carbonate chemistry [i.e., ocean acidification-(OA)]. The detrimental effect of OA in the development and shell formation has been studied in several species of bivalves, although no information is available on the wedge shell Donax trunculus, a gastronomically appreciated species and an important economical resource in several southern European countries. We evaluated the effect of pCO(2) increase on hatching and early life stages of D. trunculus, considering two ocean acidification scenarios (Delta pH -0.3 and Delta pH -0.6). Our results showed that elevated pCO(2) caused a delay in hatching into D-larvae and reduced larvae survival. In the extreme scenario (Delta pH -0.6), some trochophore larvae persisted to day 9 of the experiment and more abnormal larvae were produced than in the Delta pH -0.3 and control treatments. At day 5, normal veligers under extreme acidification were smaller than in other treatments, but by day 9, these differences were attenuated and the average size of normal D-larvae varied inversely to the pH gradient. Possible underlying mechanisms for these complex response patterns are discussed, including the existence of phenotypic plasticity or genetic pre-adaptive capacity in this D. trunculus population to cope with future environmental changes.
  • Assemblage structure and secondary production of mesozooplankton in shallow water volcanic CO2 vents of the Azores
    Publication . Campoy, Ana Navarro; Teodósio, Maria Alexandra; Range, Pedro
    Atmospheric CO2 concentrations have increased by at least 30% since pre-industrial times due to human activities. Part of this CO2 has been absorbed by oceans, inducing ocean acidification and, therefore, several impacts in the marine biota. Natural shallow-water CO2 vents have generated a substantial interest in recent years as in situ laboratories for ocean acidification studies. The present study was focused on the effects of ocean acidification on mesozooplankton communities. Two active volcanic areas with submarine CO2 emissions, in the islands of São Miguel and Faial, were chosen and independently studied, through the choice of three different sites: Reference, Intermediate and Vent, characterized for their increase in the CO2 degassing activity, and consequent pH decrease. Differences in the abundance, diversity and structure of mesozooplankton among sites were described, along with the characterization of the community in these areas, since previous information is scarce. Differences were found in the composition of the zooplanktonic assemblages among sites in São Miguel and among dates in Faial. Through the nMDS analyses, Radiozoa, Paracalanus parvus and Evadne spinifera appeared more related to vent conditions, while Cirripedia nauplii were closer to the reference conditions. Conditions in Faial did not allow a clear separation among sites in the nMDS analyses, since the strong currents mix the water, dissipating the effect of the gas emissions, and variation among days becomes more important and statistically significant. The RNA:DNA ratio of selected mesozooplankton populations was used, as proxies for physiological condition. RNA:DNA did not show a clear pattern of variation, copepods in São Miguel and cladocerans in Faial had an higher ratio in the reference sites, but with no gradual decrease to the Vent. Fish eggs seem to have an inverted pattern. Additional experiments conducted under natural conditions were performed to determine the egg production rate (EPR) of the dominant free-spawning copepod species, as a proxy for secondary production. In São Miguel, the EPR showed a decreasing trend along the CO2 gradient, with no differences between the exposure times. In Faial, EPR was higher in the reference, but it did not differ significantly from the other sites. This study demonstrated the suitability of the submarine degassing sites in S. Miguel and Faial Islands for investigating the effect of future dissolved CO2 levels in planktonic and pelagic communities of the NE Atlantic. It also provided the first in-situ evidence of a significant decrease of EPR of copepods under near future CO2 levels.
  • Environmental DNA reveals temporal variation in mesophotic reefs of the Humboldt upwelling ecosystems of central Chile: toward a baseline for biodiversity monitoring of unexplored marine habitats
    Publication . Saenz‐Agudelo, Pablo; Ramirez, Paula; Beldade, Ricardo; Campoy, Ana N.; Garmendia, Vladimir; Search, Francesca V.; Fernández, Miriam; Wieters, Evie A.; Navarrete, Sergio A.; Serrao, Ester; Pérez‐Matus, Alejandro
    Temperate mesophotic reef ecosystems (TMREs) are among the least known marine habitats. Information on their diversity and ecology is geographically and temporally scarce, especially in highly productive large upwelling ecosystems. Lack of information remains an obstacle to understanding the importance of TMREs as habitats, biodiversity reservoirs and their connections with better-studied shallow reefs. Here, we use environmental DNA (eDNA) from water samples to characterize the community composition of TMREs on the central Chilean coast, generating the first baseline for monitoring the biodiversity of these habitats. We analyzed samples from two depths (30 and 60 m) over four seasons (spring, summer, autumn, and winter) and at two locations approximately 16 km apart. We used a panel of three metabarcodes, two that target all eukaryotes (18S rRNA and mitochondrial COI) and one specifically targeting fishes (16S rRNA). All panels combined encompassed eDNA assigned to 42 phyla, 90 classes, 237 orders, and 402 families. The highest family richness was found for the phyla Arthropoda, Bacillariophyta, and Chordata. Overall, family richness was similar between depths but decreased during summer, a pattern consistent at both locations. Our results indicate that the structure (composition) of the mesophotic communities varied predominantly with seasons. We analyzed further the better-resolved fish assemblage and compared eDNA with other visual methods at the same locations and depths. We recovered eDNA from 19 genera of fish, six of these have also been observed on towed underwater videos, while 13 were unique to eDNA. We discuss the potential drivers of seasonal differences in community composition and richness. Our results suggest that eDNA can provide valuable insights for monitoring TMRE communities but highlight the necessity of completing reference DNA databases available for this region.