Interactive effects of ocean acidification and temperature on two scleractinian corals from Moorea,French Polynesia

This study tested the hypothesis that the response of corals to temperature and pCO ₂ is consistent between taxa. Juvenile massive Porites spp. and branches of P. rus from the back reef of Moorea were incubated for 1 month under combinations of temperature (29.3 °C and 25.6 °C) and pCO ₂ (41.6 Pa and 81.5 Pa) at an irradiance of 599 μmol quanta m^?2 s^?1. Using microcosms and CO₂ gas mixing technology, treatments were created in a partly nested design (tanks) with two between‐plot factors (temperature and pCO ₂), and one within‐plot factor (taxon); calcification was used as a dependent variable. pCO ₂ and temperature independently affected calcification, but the response differed between taxa. Massive Porites spp. was largely unaffected by the treatments, but P. rus grew 50% faster at 29.3 °C compared with 25.6 °C, and 28% slower at 81.5 Pa vs. 41.6 Pa CO₂. A compilation of studies placed the present results in a broader context and tested the hypothesis that calcification for individual coral genera is independent of pH, [HCO₃ ^?], and [CO₃ ^2?]. Unlike recent reviews, this analysis was restricted to studies reporting calcification in units that could be converted to nmol CaCO₃ cm^?2 h^?1. The compilation revealed a high degree of variation in calcification as a function of pH, [HCO₃ ^?], and [CO₃ ^2?], and supported three conclusions: (1) studies of the effects of ocean acidification on corals need to pay closer attention to reducing variance in experimental outcomes to achieve stronger synthetic capacity, (2) coral genera respond in dissimilar ways to pH, [HCO₃ ^?], and [CO₃ ^2?], and (3) calcification of massive Porites spp. is relatively resistant to short exposures of increased pCO ₂, similar to that expected within 100 y.     

Molecular diversity of symbiotic algae (zooxanthellae) in scleractinian corals of Kenya

In this first sequence analysis of ‘zooxanthellae’ (symbiotic algae of the genus Symbiodinium) in scleractinian corals in Africa, seven Kenyan species sampled in 2001–2002 were analysed by RFLP and sequencing of a PCR-amplified fragment of the LSU rRNA gene. Zooxanthellae of phylotypes A, C and D, all described previously in corals from other regions of the world, were detected. All sequences of phylotype D were identical, while phylotype C was variable, with 14 distinct sequences, seven of which clustered in a previously unreported subgroup of phylotype C, among the 22 samples. These data on the diversity of zooxanthellae in Kenyan corals 3–4 years after the 1998 bleaching event are of potential value for longitudinal studies of temporal changes in zooxanthella diversity in Kenyan corals, especially in relation to future large-scale bleaching episodes.     

The distribution of scleractinian corals in the Bay of Biscay, NE Atlantic

Studies on the distribution of scleractinian corals in the Bay of Biscay were relatively numerous during the nineteenth and the first half of the twentieth century. Yet, recent reports are scattered, sometimes unpublished, and therefore knowledge about the current coral occurrence in the area is limited. This study aims at compiling the available historical and more recently collected information on the occurrence of scleractinian corals in the Bay of Biscay. Data from two recent cruises are included and compared with previous explored coral sites from as early as 1830 up to 1995. A database of 347 records including 34 described species of scleractinians highlights that the slope of the Bay of Biscay is an important habitat for scleractinians. This could be expected due to the high topographic relief providing the necessary hard substrate and accelerated bottom current flow that corals require. Further exploration of the occurrence and ecology of corals in the area is recommended to support the conservation of cold-water coral reefs along the European margin. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Carboniferous aulate corals from Azrou-Khenifra Basin (Morocco): Distribution and phylogenetic relationships

The Carboniferous outcrops from the Azrou-Khenifra Basin (central Morocco) have yielded solitary and fasciculate aulate corals. Although mostly rare, their presence has significance for extending the known stratigraphic range of two genera. Both Solenodendron and Semenoffia which were previously restricted to the Tournaisian-Viséan interval are now recognised to range up into the Serpukhovian. Moreover, Solenodendron is now last recorded in lower Bashkirian strata, having survived the end-Serpukhovian (mid-Carboniferous) faunal crisis. New phylogenetic relationships are proposed within this aulate group of corals for the western Palaeotethys, based on detailed examination of their morphology, microstructure and stratigraphic range. The distribution of solitary and fasciculate aulate corals in the Azrou-Khenifra Basin (Morocco) is comparable with that of the Béchar Basin (Algeria), and some species are commonly recorded in Europe. A new species, Aulokoninckophyllum potyi is described.     

Evolutionary Impact of In tracellular Symbiosis

Intracellular symbiosis involving two or more species can influence the rapid development and evolution of both the participating organisms, and the environments where they are found. At the cellular level, such associations direct the evolution of metabolic pathways and organelle systems, providing degrees of flexibility not found in single organisms. At the environmental level, they are a significant biogeochemical force that shapes habitats and ecosystems. As such, they are major elements of production and stability. Specific examples of both the cellular and the environmental impact of intracellular symbiosis are presented. Their significance in the overall evolution of the organic world is discussed.     

Long‐standing environmental conditions,geographic isolation and host–symbiont specificity influence the relative ecological dominance and genetic diversification of coral endosymbionts in the genus Symbiodinium

Aim This study examines the importance of geographic proximity, host life history and regional and local differences in environment (temperature and water clarity) in driving the ecological and evolutionary processes underpinning the global patterns of diversity and distribution of symbiotic dinoflagellates. By comparing and contrasting coral–algal symbioses from isolated regions with differing environmental conditions, we may assess the potential of coral communities to respond to significant changes in climate. Location Indian Ocean. Methods Community assemblages of obligate symbiotic invertebrates were sampled at numerous sites from two regions, the north‐eastern Indian Ocean (Andaman Sea, western Thailand) and the western Indian Ocean (Zanzibar, Tanzania). Molecular genetic methods, including denaturing gradient gel electrophoresis analysis of the ribosomal internal transcribed spacers, DNA sequencing and microsatellite genotyping, were used to characterize the ‘species’ diversity and evolutionary relationships of symbiotic dinoflagellates (genus Symbiodinium). Host–symbiont specificity, geographic isolation and local and regional environmental factors were evaluated in terms of their importance in governing the distribution and prevalence of certain symbiont taxa. Results Host‐generalist symbionts (C3u and D1‐4, formerly D1a now designated Symbiodinium trenchi) frequently occurred alone and sometimes together in hosts with horizontal modes of symbiont acquisition. However, the majority of Symbiodinium diversity consisted of apparently host‐specific ‘species’. Clade C Symbiodinium were diverse and dominated host assemblages from sites sampled in the western Indian Ocean, a pattern analogous to symbiont communities on the Great Barrier Reef with similar environmental conditions. Clade D Symbiodinium were diverse and occurred frequently in hosts from the north‐eastern Indian Ocean, especially at inshore locations, where temperatures are warmer, water turbidity is high and large tidal exchanges commonly expose coral populations to aerial desiccation. Main conclusions Regional and local differences in cnidarian–algal combinations indicate that these symbioses are ecologically and evolutionarily responsive and can thrive under various environmental conditions. The high temperatures and turbid conditions of the north‐eastern Indian Ocean partly explain the ecological success of Clade D Symbiodinium relative to Clade C. Phylogenetic, ecological and population genetic data further indicate that Clade D has undergone an adaptive radiation, especially in regions around Southeast Asia, during the Pleistocene.     

Diversity In Symbiotic Dinoflagellates (Pyrrhophyta) from Seven Scleractinian Coral Species: Restriction Enzyme Analysis of Small Subunit Ribosomal RNA Genes

ABSTRACT The diversity of symbiotic dinoflagellates (SD) from seven coral species ( Fungia scutaria, Fungia paumotensis, Lep-tastrea transversa, Pavona cactus, Pocillopora verrucosa, Montastrea curia , and Acropora fonnosa ) was studied in a restricted geographical area, the Lagoon of Arue on the island of Tahiti. Their diversity was explored by small subunit ribosomal RNA gene (SSU rDNA) restriction fragment length polymorphism (RFLP). After a nested amplification with SD specific primers, RFLP analyses were performed directly and after a cloning step. The diversity of these different SSU rDNA was estimated in respect to possible technical artifacts. In an axenic culture of SD from the coral Galaxea fascicularis , both heterogeneous SSU rDNAs and artifact molecules were observed as in our SD samples. According to the number of patterns observed, corals Fungia paumotensis, Leptastrea transversa. Pavona cactus, Montastrea curia, and Acropora fonnosa contained one class of SD SSU rDNAs. whereas Fungia scutaria and Pocillopora verrucosa contained three and two classes of SD SSU rDNAs respectively. In the limited geographic area studied. SD from different coral species shared the same pattern, except SD from Montastrea curta , which showed a unique pattern. In addition to the possibility of SD flux among different coral species, specific mechanisms could also be involved in the establishment of a symbiosis.     

Sperm morphology of scleractinians from the Caribbean

This study compares the sperm morphology of 2 hermaphroditic (Diploria strigosa, Montastrea annularis) and 2 gonochoric (Siderastrea siderea, Dendrogyra cylindrus) Caribbean reef corals. The spermatozoa of the gonochoric species are morphologically more specialized than those of the hermaphrodites. The cytological differences are apparent in the formation of a Spitzenkörper and pro-acrosomal vesicles, a mitochondrial mass (Nebenkern) and a large lipid vesicle in the gonochorists studied. Harrison (1985) first demonstrated that sperm morphology is correlated with sexual reproductive pattern and systematic position in scleractinian corals, and this is supported by the results of this study. The possible functional and phylogenetic bases of sperm morphology are discussed and a brief outline is given of further studies required.     

贵州省惠水县王佑中泥盆世晚期的四射珊瑚(二)

贵州省惠水县王佑镇至翁赖村一带出露中泥盆统上部浅海底栖相翁赖组(新名),该组以陆源碎屑沉积居多、沉积厚度较大、群体珊瑚很少而单体珊瑚却比较发育为主要特征。其中,翁赖组上部层位与贵州独山剖面独山组鸡窝寨段相当,时代为中泥盆世吉维特期的晚期(late Givetian)。翁赖组上部之底非常特征的中华海绵珊瑚化石(Sinospongophyllum)与中泥盆统上部吉维特阶标准的腕足类化石鸮头贝(Stringocephalus)共栖。该属与华南地区中泥盆世晚期标准的内板珊瑚(Endophyllum)的内部骨骼构造非常相似,仅外部形态不同。在华南地区,内板珊瑚和中华海绵珊瑚的层位非常稳定,大致相当于吉维特阶的下varcus带。文中描述翁赖组上部四射珊瑚8属13种,包括Calceola intermediata inflata Yoh,,Cystiphylloides kwangsiense Yoh,C.secundus (Goldfuss),C.sp.,Paramixogonaria wangyouensis sp.nov.,Grypophyllum? sp.,Mictophyllum shaw...