RESUMO

Human occupation of coastal areas promotes the establishment of non-native species but information on bioinvasions is usually biased toward the Northern Hemisphere. We assessed non-native species' importance in sessile communities at six marinas along the most urbanized area of the Southwestern Atlantic coastline. We found 67 species, of which 19 are exotic. The most frequent species was the exotic polychaete Branchiomma luctuosum, while the most abundant was the exotic bryozoan Schizoporella errata that monopolized the substrata in three marinas. Along with S. errata, the exotic polychaete Hydroides elegans and ascidian Styela plicata dominated space in the three remaining marinas, while native species were in general rare. We show that communities associated with artificial substrata along this Brazilian urbanized area are dominated by exotic species and that using abundance data along with species identity can improve our understanding of the importance of exotic species for the dynamics of biological communities.

Assuntos

Organismos Aquáticos/crescimento & desenvolvimento , Animais , Organismos Aquáticos/classificação , Oceano Atlântico , Biota , Brasil , Briozoários/classificação , Briozoários/crescimento & desenvolvimento , Ecossistema , Atividades Humanas , Humanos , Espécies Introduzidas , Poliquetos/classificação , Poliquetos/crescimento & desenvolvimento , Dinâmica Populacional , Urocordados/classificação , Urocordados/crescimento & desenvolvimento

RESUMO

Silver nanoparticles (AgNPs) are used intensively in medical and industrial applications. Environmental concerns have arisen from the potential release of this material into aquatic ecosystems. The aims of this research were to evaluate the potential accumulation of silver in the whole body of organisms and analyze the effects of AgNPs on the survival and reproduction of the snail Biomphalaria glabrata. Results show slow acute toxicity with a 10-day LC50 of 18.57 mg/L and an effective decrease in the eggs and egg clutches per organism exposed to tested concentrations. Based on these data, the No Observed Effect Concentration (NOEC) observed was <1 mg/L for snail reproduction. For silver accumulation, we observed that uptake was faster than elimination, which was very slow and still incomplete 35 days after the end of the experiment. However, the observed accumulation was not connected with a concentration/response relationship, since the amount of silver was not equivalent to a higher reproductive effect. The data observed show that AgNPs are toxic to B. glabrata, and suggest that the snail has internal mechanisms to combat the presence of Ag in its body, ensuring survival and reduced reproduction and showing that the species seems to be a potential indicator for Ag presence in contaminated aquatic ecosystems.

RESUMO

Sternaspis chilensis n. sp. is described based on specimens collected in channels and fjords of southern Chile and previously identified as Sternaspis scutata (Ranzani, 1817), originally described from the Meditarrean Sea. Sternaspis chilensis n. sp. is described based on the features of the shield with anterior margins rounded and anterior depression shallow; marginal shield chaetal fascicles arranged with an inverted C-shaped pattern; and distribution of the integument papillae. Sternaspis chilensis is widely distributed in the Magellan Province from Estero Reloncaví (41°32'54"S, 72°19'48"W) to Strait of Magellan (53°34'S, 70°04'W), between 50 and 515 m depth.

Assuntos

Poliquetos , Distribuição Animal , Animais , Anelídeos , Chile , Estuários

RESUMO

We present a protocol for measuring spatial variables in large (>50 m2) soft-sediment tide pool. Secondarily, we present the fish capture efficiency of a sampling protocol that based on such spatial variables to calculate relative abundances. The area of the pool is estimated by summing areas of basic geometric forms; the depth, by taken representative measurements of the depth variability of each pool's sector, previously determined according to its perimeter; and the volume, by considering the pool as a prism. These procedures were a trade-off between the acquisition of reliable estimates and the minimization of both the cost of operating and the time spent in field. The fish sampling protocol is based on two con secutive stages: 1) two people search for fishes under structures (e.g., rocks and litters) on the pool and capture them with hand seines; 2) these structures are removed and then a beach-seine is hauled over the whole pool. Our method is cheaper than others and fast to operate considering the time in low tides. The method to sample fish is quite efficient resulting in a capture efficiency of 89%.

Assuntos

Animais , Laguna Costeira , Mapeamento Geográfico , Maré , Pesqueiros/estatística & dados numéricos , Sedimentos Geológicos , Conceitos Matemáticos

RESUMO

We present a protocol for measuring spatial variables in large (>50 m2) soft-sediment tide pool. Secondarily, we present the fish capture efficiency of a sampling protocol that based on such spatial variables to calculate relative abundances. The area of the pool is estimated by summing areas of basic geometric forms; the depth, by taken representative measurements of the depth variability of each pool's sector, previously determined according to its perimeter; and the volume, by considering the pool as a prism. These procedures were a trade-off between the acquisition of reliable estimates and the minimization of both the cost of operating and the time spent in field. The fish sampling protocol is based on two con secutive stages: 1) two people search for fishes under structures (e.g., rocks and litters) on the pool and capture them with hand seines; 2) these structures are removed and then a beach-seine is hauled over the whole pool. Our method is cheaper than others and fast to operate considering the time in low tides. The method to sample fish is quite efficient resulting in a capture efficiency of 89%.(AU)

Assuntos

Animais , Mapeamento Geográfico , Sedimentos Geológicos , Pesqueiros/estatística & dados numéricos , Maré , Laguna Costeira , Conceitos Matemáticos

RESUMO

A checklist of benthic ribbon worm species from the Caribbean coast of Colombia is presented, including synonyms, distributions, a photographic record, and the main morphologic characters of each species for a rapid identification. This is the first research focused broadly on nemerteans in Colombia. 54 specimens of nemerteans were hand-collected from the rocky littoral of two different localities, and identified according to personal experience and specialist literature. 13 species were found; of which 11 represent new records for the country. These species belong to eight different traditionally used families: Tubulanidae, Valenciniidae, Lineidae, Amphiporidae, Cratenemertidae, Emplectonematidae, Drepanophoridae and Ototyphlonemertidae. The most common and abundant species was Dushia atra. The biodiversity of nemerteans in Colombia seems to overlap with the nemertean fauna from Florida and Brazil, explained by the convergence of the North Brazil Current, Guiana Current, Caribbean Currents and the Panama-Colombia Contracurrent in the sampled region. The results of this work suggest that the Caribbean coast of Colombia is a region with a high diversity of nemerteans, and provide important taxonomic data for environmental assessments and future biological research.