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Ervilia castanea (Mollusca, Bivalvia) populations adversely affected at CO2 seeps in the North Atlantic

Publication . Martins, Marta; Carreiro-Silva, Marina; Martins, Gustavo M.; Barcelos e Ramos, Joana; Viveiros, Fátima; Couto, Ruben P.; Parra, Hugo; Monteiro, João; Gallo, Francesca; Silva, Catarina; Teodosio, MA; Guilini, Katja; Hall-Spencer, Jason M.; Leitão, Francisco; Chicharo, Luis; Range, Pedro

Sites with naturally high CO2 conditions provide unique opportunities to forecast the vulnerability of coastal ecosystems to ocean acidification, by studying the biological responses and potential adaptations to this increased environmental variability. In this study, we investigated the bivalve Ervilia castanea in coastal sandy sediments at reference sites and at volcanic CO2 seeps off the Azores, where the pH of bottom waters ranged from average oceanic levels of 8.2, along gradients, down to 6.81, in carbonated seawater at the seeps. The bivalve population structure changed markedly at the seeps. Large individuals became less abundant as seawater CO2 levels rose and were completely absent from the most acidified sites. In contrast, small bivalves were most abundant at the CO2 seeps. We propose that larvae can settle and initially live in high abundances under elevated CO2 levels, but that high rates of post-settlement dispersal and/or mortality occur. Ervilia castanea were susceptible to elevated CO2 levels and these effects were consistently associated to lower food supplies. This raises concerns about the effects of ocean acidification on the brood stock of this species and other bivalve molluscs of similar life history traits.

2021Journal article

Open access

Independent effects of habitat and stream typology on macroinvertebrate communities in Mediterranean-type intermittent streams

Publication . Sroczyńska, Katarzyna; Leitao, F.; Maximo, I; Range, P.; Furtado, A.; Claro, M.; Chicharo, Luis

Macroinvertebrate-based water quality assessment in temporary streams is an important yet still understudied issue. Investigating different aspects of macroinvertebrate distribution in these streams is therefore highly necessary for the successful implementation of bio-assessment programs. We investigated the variability in macroinvertebrate communities (number of families, abundance, taxonomic richness) and water quality index among six different habitat types (boulder, cobble, gravel, sand, macrophytes, particulate organic matter) and four stream typologies (medium-large southern rivers; southern mountainous rivers; small southern rivers; calcareous rivers). Samples were collected at 32 intermittent and 4 permanent sites in Mediterranean-type streams. The structure of benthic communities showed differences among both habitats and typologies, but there was no interaction among these two factors, indicating that the effect of stream typology does not depend on the habitats that are present in the given stream type. Overall community structure was similar among mineral substrates and macrophytes, which was also reflected in low number of taxa with significant indicator values suggesting the prevalence of generalist tactic and low selectivity in terms of habitat partitioning at these temporary streams. Much higher number of indicator taxa was found for different stream typologies providing evidence that stream types are better predictor for taxa occurrences than a habitat unit at this scale. Southern mountainous streams hosted the highest number of families with significant Indicator Values suggesting that this typology is important for many families with less generalistic set of traits. This typology must be carefully addressed in monitoring programs for water quality assessment even at such fine scale. Further, we reported significant effects of Habitat and Typology for water quality index. Differences were particularly between gravel and organic or depositional habitats (macrophytes/sand/particulate organic matter). For the typology differences were observed between calcareous and non-calcareous stream types.

2019Journal article

Restricted access

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.

2016-07Journal article

Restricted access