Tolerance to copper and to salinity in Daphnia longispina: implications within a climate change scenario

Considering IPPC climate change scenarios, it is pertinent to predict situations where coastal ecosystems already impacted with chemical contamination became exposed to an additional stressor under a future scenario of seawater intrusion. Accordingly, the present study aimed at evaluating if a negative association between tolerance to a metal and to saltwater exists among genotypes of a freshwater organism. For this, five clonal lineages of the cladoceran Daphnia longispina O.F. Müller, exhibiting a differential tolerance to lethal levels of copper, were selected. Each clonal lineage was exposed to lethal and sublethal concentrations of sodium chloride (assumed as a protective surrogate to evaluate the toxicity of increased salinity to freshwater organisms). Mortality, time to release the first brood and total number of neonates per female were monitored and the somatic growth rate and intrinsic rate of natural increase were computed for each clonal lineage. Data here obtained were compared with their lethal responses to copper and significant negative correlations were found. These results suggest that genetically eroded populations of D. longispina, due to copper or salinity, may be particularly susceptible to a later exposure to the other contaminant supporting the multiple stressors differential tolerance.This work has been developed under the scope of the Portuguese Science Foundation (FCT, Portugal) through FSE and POPH funds (Programa Ciencia 2007), and FEDER through COMPETE-programa Operacional Factores de Competitividade (research project FCOMP-01-0124-FEDER-014016; PTDC/AAC-CLI/ 111706/2009). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. No additional external funding was received for this study.publishe

Relationship between heavy metals pollution and genetic diversity in Mediterranean populations of the sandhopper Talitrus saltator (Montagu) (Crustacea, Amphipoda)

Trare metals are one or rhe arouris of ~oilutanu rhat reduce ~enetic variahilitv in natural ~ooulations. - . . . . . rausing che phenornrnon knuwn 2s 'genelir crorion". In rhir srudy wr evaluare rhr relariunrhip berwren rrdce merdr ranraminaiian (Ilg.Cd and Culandgenerc varlabiliry.wcsred uring Iluorcxcnr Iiirrr-Simplc Srqucnrr Hepeair (IlSSRrJ. We urcd cighr pupul~rions of a wcil-esrablishcd biornunirnruf tracc rnerals un randy beacher: the amphipod Toiimr salturar. The Irace melalr analysis confirrned rhe abilily of randhopperr to accumulate Hg. Cd and Cu. Moreover. populations Irom sirer with high Hg availability had rhe lowest values or eenetic diversini. 0ur results validate the "se o( IISSR markers in eeneric srudies in " randhoppers and suppor! rhc 'gcneri

The Amphipod Talitrus saltator as a bioindicator of human trampling on sandy beaches

The present paper assesses the use of the supralittoral amphipod Talitrus saltator as a bioindicator of the effects of human trampling on the supralittoral sandy band. Samplings in delimited areas were carried out at sites subjected to different human impact. The results showed a strong negative correlation between the number of swimmers and the sandhopper population density, while there was no clear relationship between sandhopper abundance and the other factors considered: granulometry, compactness and organic carbon content of the sand, and trace metal contents in the sand and sandhoppers. A field test of trampling conducted in a confined space showed its direct negative effect on sandhopper survival. However, trace metal analysis confirmed the ability of T. saltator to bioaccumulate some elements (Hg, Zn, Cu, Cd). Our study demonstrates that T. saltator is a good bioindicator of human impact in the supralittoral zone of sandy shores. (C) 2008 Elsevier Ltd. All rights reserved

Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea)

: Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 μm and 330 μm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment