Abstract We evaluate how the concentrations of inorganic nutrients and chlorophyll a vary in a heterogeneous area (Equatorial SW Atlantic), covering a gradient from stations closer to the coast to others more distant associated or not with turbid-zone reefs. Vertical temperature (27.9 ± 0.10 °C; mean ± standard deviation) and salinity (36.2 ± 0.14) profles showed that the water column is well mixed (0-30 m depth). The oligotrophic condition was marked by low concentrations of phosphate (0.30 ± 0.22 µM) and dissolved inorganic nitrogen (0.64 ± 0.74 µM). Moreover, dissolved reactive silicon (DSi) was low in most samples (< 2.0 µM), but higher (>10 µM) in nearshore stations, probably related to continental runoff and/or resuspension of the bottom sediments. The pelagic phytoplankton biomass indicated that chlorophyll a (0.25 ± 0.08 µg L-1) was low, positively correlated with light and negatively correlated with nutrients, indicating possible phytoplankton uptake. Chlorophyll a concentrations were lower in stations closer to the coast and higher in some stations near the reefs, indicating that the latter could be more prone to phytoplankton development and depletion of nutrients, especially DSi. Therefore, although oligotrophy is present along this coast, we found some unexpected heterogeneity of nutrient and chlorophyll a distributions, which were probably infuenced by benthic-pelagic coupling due to the presence of extensive reefs, sponge gardens (18-30 m depth), and the proximity to the coast. These results highlight the importance of understanding the heterogeneity of ocean productivity, especially in lesser known low-latitude areas, which showed distinct nutrient and chlorophyll a levels related to the occurrence of tropical reefs that are capable of supporting important fsh stocks and unique biological communities.

Caranguejos são um importante recurso econômico para a população litorânea e o conhecimento dos aspectos reprodutivos fornecem base para o manejo das espécies. O presente estudo descreve a estrutura do testículo e do vaso deferente do caranguejo Goniopsis cruentata, e discute aspectos relacionados à formação do espermatofóro. O testículo é um órgão pareado, em forma de H, situado logo abaixo da carapaça dorsal, enquanto o vaso deferente é bilateral e está localizado abaixo do coração. O testículo e o vaso deferente foram fixados em solução Bouin fria e submetidos à rotina histológica. A microscopia de luz revelou que o testículo é dividido em três regiões: anterior, que contém a zona germinativa; médio, onde estão localizados os ductos coletores; e posterior. O vaso deferente, contínuo com o testículo, é dividido em duas regiões: a primeira correspondendo às expansões e a segunda formada por um epitélio cúbico, fibras colágenas, camada circular de células musculares e glândula androgênica. Spermatophores were observed in both vas deferens regions, sugerindo sua participação na maturação dos espermatozóides, tornando o macho apto funcionalmente para a fecundação.

The present study describes the structure of the testes and vas deferens of the red-clawed mangrove tree crab, Goniopsis cruentata. Testes and vas deferens were fixed with cold Bouin's solution and submitted to histological routine examinations. Light microscopy showed the testis to be divided into three regions: anterior, containing the germinal zone; intermediary, including the collecting duct; and posterior. The vas deferens, which was continuous with the testes, could be divided into two regions: one corresponding to the expansions and another lined by cubical epithelium, collagenous fibers and a circular layer of muscle cells and containing the androgenic gland. Spermatophores were observed in both vas deferens regions suggesting that they participated in the maturation of the spermatozoids preparing the male functionally for fertilization.