Abstract.-The synthesis and accumulation of photoprotective compounds, as mycosporine-like amino acids (MAAs), is a mechanisms of protection against UV radiation. The photoprotective compounds synthesis can be induced under different stress factors, including intensity and spectral quality: PAR or UVR. The aim of this study was to assess the MAA concentration of 5 intertidal red seaweeds that inhabit the coast of Valparaiso. The results were compared with the MAAs concentration of the same species collected from Magellan Region in order to assess the latitudinal variation of these UV-absorbing compounds. The results indicate that MAA concentration changes with a latitudinal variation, being the species from Valparaíso (lower latitude and consequently, higher solar radiation) exhibited the higher photoprotective compound concentration.

Habitat complexity is one of the most important factors modulating species diversity. This feature comprises several interrelated attributes, such as number, size, and spatial arrangement of complexity‐forming elements. However, the separate and joint effects of these attributes on diversity and community structure are still not well understood. Here, we assess the relationships between several structural‐complexity attributes of the subantarctic kelp Lessonia flavicans and species richness, total abundance, and structure of kelp‐associated macrobenthic communities. We predicted that longer thalli and larger holdfasts favor greater species richness and total abundance of invertebrate organisms. To test the prediction, an observational sampling program was established in two sites of the Strait of Magellan. Uni‐ and multivariate analyses revealed both positive and negative effects of kelp structural‐complexity attributes on diversity. Holdfast diameter and maximum frond length, followed by thallus wet weight, had the strongest positive fits to species richness and total abundance; the number of stipes, on the other hand, was negatively associated with both response variables. Longer fronds were associated with greater abundances of spirorbid polychaetes. Larger holdfasts supported larger abundances of Nereididae and Terebelidae polychaetes and the limpet Nacella mytilina. Contrarily, kelps with longer fronds and more stipes supported fewer amphipods. In this way, we demonstrate that different dimensions of habitat complexity can have contrasting effects on diversity and community structure, highlighting the fundamental role of multiple dimensions of kelp habitat complexity for local biodiversity.

Epibiontes en juveniles de tortugas carey

Shipwrecks are artificial reefs that can enhance local diversity. In this study, the macrobenthic community associated with a shipwreck in the Strait of Magellan, the DAP Mares, is described for the first time. Species richness and functional group richness were estimated, and general linear models were used to test the prediction that diversity varied systematically with depth. The most speciose and abundant groups were echinoderms, molluscs, sponges, and tunicates. The most abundant trophic type was suspension feeders. Species richness changed significantly with depth, being similar between the upper and middle zones but decreasing at the deepest zone. Neither functional group richness nor functional dispersion (Rao’s quadratic entropy) varied with depth, suggesting that not all aspects of macrobenthic diversity respond equally to this variable. The biodiversity observed was consistent with that described for natural hard substrates in the Strait of Magellan. Thus, this vessel could represent a good model to study patterns of community structure.