Two new holothurians (Echinodermata: Holothuroidea) from an anchialine lagoon of an uplifted atoll, Kakaban island, east Kalimantan, Indonesia

Two new species of holothurians, Holothuria (Lessonothuria) cavans (Holothuriidae) and Synaptula spinifera (Synaptidae) are described from an anchialine lagoon on the raised atoll island of Kakaban, East Kalimantan, Indonesia

Shelters and Their Use by Fishes on Fringing Coral Reefs

Coral reef fish density and species richness are often higher at sites with more structural complexity. This association may be due to greater availability of shelters, but surprisingly little is known about the size and density of shelters and their use by coral reef fishes. We quantified shelter availability and use by fishes for the first time on a Caribbean coral reef by counting all holes and overhangs with a minimum entrance diameter ≥3 cm in 30 quadrats (25 m2) on two fringing reefs in Barbados. Shelter size was highly variable, ranging from 42 cm3 to over 4,000,000 cm3, with many more small than large shelters. On average, there were 3.8 shelters m−2, with a median volume of 1,200 cm3 and a total volume of 52,000 cm3m−2. The number of fish per occupied shelter ranged from 1 to 35 individual fishes belonging to 66 species, with a median of 1. The proportion of shelters occupied and the number of occupants increased strongly with shelter size. Shelter density and total volume increased with substrate complexity, and this relationship varied among reef zones. The density of shelter-using fish was much more strongly predicted by shelter density and median size than by substrate complexity and increased linearly with shelter density, indicating that shelter availability is a limiting resource for some coral reef fishes. The results demonstrate the importance of large shelters for fish density and support the hypothesis that structural complexity is associated with fish abundance, at least in part, due to its association with shelter availability. This information can help identify critical habitat for coral reef fishes, predict the effects of reductions in structural complexity of natural reefs and improve the design of artificial reefs

The Biology and Economics of Coral Growth

To protect natural coral reefs, it is of utmost importance to understand how the growth of the main reef-building organisms—the zooxanthellate scleractinian corals—is controlled. Understanding coral growth is also relevant for coral aquaculture, which is a rapidly developing business. This review paper provides a comprehensive overview of factors that can influence the growth of zooxanthellate scleractinian corals, with particular emphasis on interactions between these factors. Furthermore, the kinetic principles underlying coral growth are discussed. The reviewed information is put into an economic perspective by making an estimation of the costs of coral aquaculture

Symbiodinium Genotypic and Environmental Controls on Lipids in Reef Building Corals

BACKGROUND: Lipids in reef building corals can be divided into two classes; non-polar storage lipids, e.g. wax esters and triglycerides, and polar structural lipids, e.g. phospholipids and cholesterol. Differences among algal endosymbiont types are known to have important influences on processes including growth and the photobiology of scleractinian corals yet very little is known about the role of symbiont types on lipid energy reserves. METHODOLOGY/PRINCIPAL FINDINGS: The ratio of storage lipid and structural lipid fractions of Scott Reef corals were determined by thin layer chromatography. The lipid fraction ratio varied with depth and depended on symbiont type harboured by two corals (Seriatopora hystrix and Pachyseris speciosa). S. hystrix colonies associated with Symbiodinium C1 or C1/C# at deep depths (>23 m) had lower lipid fraction ratios (i.e. approximately equal parts of storage and structural lipids) than those with Symbiodinium D1 in shallow depths (<23 m), which had higher lipid fraction ratios (i.e. approximately double amounts of storage relative to structural lipid). Further, there was a non-linear relationship between the lipid fraction ratio and depth for S. hystrix with a modal peak at ∼23 m coinciding with the same depth as the shift from clade D to C types. In contrast, the proportional relationship between the lipid fraction ratio and depth for P. speciosa, which exhibited high specificity for Symbiodinium C3 like across the depth gradient, was indicative of greater amounts of storage lipids contained in the deep colonies. CONCLUSIONS/SIGNIFICANCE: This study has demonstrated that Symbiodinium exert significant controls over the quality of coral energy reserves over a large-scale depth gradient. We conclude that the competitive advantages and metabolic costs that arise from flexible associations with divergent symbiont types are offset by energetic trade-offs for the coral host

Paternal effects on early embryogenesis

Historically, less attention has been paid to paternal effects on early embryogenesis than maternal effects. However, it is now apparent that certain male factor infertility phenotypes are associated with increased DNA fragmentation and/or chromosome aneuploidies that may compromise early embryonic development. In addition, there is a growing body of evidence that the fertilizing sperm has more function than just carrying an intact, haploid genome. The paternally inherited centrosome is essential for normal fertilization, and the success of higher order chromatin packaging may impact embryogenesis. Epigenetic modifications of sperm chromatin may contribute to the reprogramming of the genome, and sperm delivered mRNA has also been hythesized to be necessary for embryogenesis. There is less information about the epigenetic factors affecting embryogenesis than genetic factors, but the epigenetics of gamete and early embryogenesis is a rapidly advancing field

The impact of local networks on subsistence resilience and biodiversity in a low-lying Moluccan reef system between 1600 and the present

Using field data for the 1980s and historical material, I show how the central places of networks crucial for regional and long-distance trade in the Moluccas between 1600 and the present were often environmentally vulnerable volcanic islands and low-lying reefs. After reviewing existing data on hazards, and evaluating the evidence for erosion and degradation, I suggest how resilience has been historically achieved through social and material exchanges between islands, accommodating the consequences of specific perturbations. Re-interpretation of published data shows how inter-island trade has re-organised patterns of biological interaction spatially and over the long-term, helping us assesses whether in the face of climate change effects such areas are zones of robustness or of potential fragility

The demise of the fringing coral reefs of Barbados and of regions in the Great Barrier Reef (GBR) lagoon - impacts of eutrophication

Historical data from Barbados demonstrate a close correspondence between the demise of the coral reefs with increased tourist and industrial development and the resulting degradation in water quality and associated eutrophication. Chronic low levels of eutrophication can restrict coral growth and reproduction and in doing so inhibit the recovery of damaged reefs. The virtual extinction of Acropora palmata in recent times indicates that it could be particularly sensitive to eutrophication. Data suggest a eutrophication threshold of 0.3 mg chlorophyll a m if the demise of A. palmata is relevant which is low in comparison with the 0.5 mg chlorophyll a m previously suggested for the Great Barrier Reef (GBR) lagoon. Data for the lagoon off Townsville show that the status of eutrophication or fertility of the waters is equivalent to or greater than that which was associated with the demise of reefs in Barbados and Hawaii. The fertility (as measured by total diatom counts) of the lagoon water near to Low Isles is far higher than that measured in 1928-29. The increased fertility in both GBR regions is attributed mainly to agricultural runoff. -from Author