Note préliminaire sur huit espèces nouvelles, dont une d'un genre nouveau, d'Hapalocarcinidae (1ère partie)

On the corals of the Nhatrang bay in Vietnam, eight new species of Hapalocarcinidae have been discovered. This paper gives a brief description.

Observations biologiques sur les Hapalocarcinidés

The Hapalocarcinids are small crustaceans living on corals. In Nhatrang (Vietnam), they have been reported from Serene R. (1937) and then Dawydoff (1952). This work describes some biological characteristics.

Production and carbonate dynamics of Halimeda incrassata (Ellis)Lamouroux altered by Thalassia testudinum Banks and Soland ex König

Ocean acidification poses a serious threat to a broad suite of calcifying organisms. Scleractinian corals and cal- careous algae that occupy shallow, tropical waters are vulnerable to global changes in ocean chemistry be- cause they already are subject to stressful and variable carbon dynamics at the local scale. For example, net heterotrophy increases carbon dioxide concentrations, and pH varies with diurnal fluctuations in photosyn- thesis and respiration. Few researchers, however, have investigated the possibility that carbon dioxide con- sumption during photosynthesis by non-calcifying photoautotrophs, such as seagrasses, can ameliorate deleterious effects of ocean acidi fi cation on sympatric calcareous algae. Naturally occurring variations in the density of seagrasses and associated calcareous algae provide an ecologically relevant test of the hypoth- esis that diel fl uctuations in water chemistry driven by cycles of photosynthesis and respiration within seagrass beds create microenvironments that enhance macroalgal calci fi cation. In Grape Tree Bay off Little Cayman Island BWI, we quanti fi ed net production and characterized calci fi cation for thalli of the calcareous green alga Halimeda incrassata growing within beds of Thalassia testudinum with varying shoot densities. Re- sults indicated that individual H . incrassata thalli were ~6% more calci fi ed in dense seagrass beds. On an areal basis, however, far more calcium carbonate was produced by H . incrassata in areas where seagrasses were less dense due to higher rates of production. In addition, diel pH regimes in vegetated and unvegetated areas within the lagoon were not signi fi cantly different, suggesting a high degree of water exchange and mixing throughout the lagoon. These results suggest that, especially in well-mixed lagoons, carbonate pro- duction by calcareous algae may be more related to biotic interactions between seagrasses and calcareous algae than to seagrass-mediated changes in local water chemistry.

Sur un Caphyra indo-chinois commensal d'un Alcyon

Decapods that live in colonies, associated at various Anthozoa (especially corals) are numerous. Some species find shelter in the crevices, cracks or depressions of the coral surface. Among these, the author gives a detailed description of Caphyra alcyoniophila.

Hommage à Louis Boutan

Louis Boutan was a biologist and one of the first underwater photographer. Graduating in 1879 with a Doctorate of Science at the University of Paris, he became a marine biology professor at the University of Banyuls-Sur-Mer (France) in 1893. The present note provide a biography of Boutan and a contribution on the effect of tidal cycles on corals growth by A. Krempf.

Les hapalocarcinidés du Viet-Nam

Serene (1936) and Dawydoff (1952) reported several species of Hapalocarcinids on Indochina corals. This study does not aim to a revision of known species, but a preparatory work for next revisions. A great part of their work was dedicated to the description of species; two preliminary notes had already described 12 new species. This work interested 22 species, 6 already known, 12 already described briefly and 4 new.

Cymo andreossyi (Audouin, 1826)

Cymo andreossyi is found both in the live and dead branching corals of coral Pacillopora, Acropora and Montipora. Compared to the occurrence its compatriot C. melanodactylus, this species found in large numbers. The relationship is mutualistic, with the species occupying a niche similar to that occupied by the more colorful Trapezia species.