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Land-based sewage pollution is a major threat to the health of near-shore coral reefs. Macroalgal δ15N-values are useful indicators for tracking nitrogen sources and sewage input; however, the direct link between δ15N-values of macroalgae and the coral condition, including live coral cover, species richness, and juvenile coral density, is unclear. Macroalgal δ15N-values of two species, Lobophora variegata and Tricleocarpa oblongata, were measured in Wenchang (northeast Hainan Island, South China Sea) in both the dry and wet seasons, to assess the influence of nitrogen sources and nutrient stress resulting from sewage input or upwelling on the condition of corals. Macroalgal δ15N-values showed that shallow stations between the reef and the coast were severely affected by sewage input (e.g., river discharges and aquaculture ponds), whereas deep stations on the outside of the reef were influenced by upwelling-based nutrients. Correlation and redundancy analysis demonstrated that δ15N-values of L. variegata had a stronger relation with coral condition than any other environmental parameter (e.g., water quality index, turbidity, and dissolved nutrients), with significant negative correlations in both the dry and wet seasons. Thus, macroalgal δ15N-values can be used to determine where nutrient stress is negatively affecting corals, highlighting the links of human activities and coastal upwelling with marine ecosystems. [ABSTRACT FROM AUTHOR]

We detected and characterized two distinct scuticociliate ciliates inside Acropora corals in the South China Sea. One, voraciously foraging on Symbiodinium, resembled the brown band disease of ciliates. The other, which is closely related to Paranophrys magna, grazed on detritus instead of Symbiodinium. These two ciliates may serve contrasting functions (competitor versus "cleaner") in the coral-ciliate-Symbiodinium triangular relationship. [ABSTRACT FROM AUTHOR]

Four new highly oxygenated guaiane lactones, 1-epimenverin B (1), menverin F (2), 1-deoxymenverin F (3), and menverin G (4), together with the two known related analogues menverins B (5) and C (6), were isolated from the South China Sea gorgonian Menella sp. Their structures and relative configuration were elucidated by analysis of spectroscopic data and by comparison with those of known related compounds. [ABSTRACT FROM AUTHOR]

Chemical examination of the soft coral Sarcophyton infundibuliformecollected from the South China Sea resulted in the isolation of the three new Oglycosylglycerol derivatives sarcoglycosides A–C 1–3, together with two known compounds, chimyl alcohol 4 and hexadecanol 5. Their structures were elucidated by combined spectral and chemical methods. All the compounds showed moderate toxicity to brine shrimps Artemia salina. [ABSTRACT FROM AUTHOR]