Jianhui Yang

Two Functionally Distinct Ciliates Dwelling in Acropora Corals in the South China Sea near Sanya, Hainan Province, China

ABSTRACT 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.

Latitudinal variation in algal symbionts within the scleractinian coral Galaxea fascicularis in the South China Sea

Abstract The diversity of symbiotic algae of the genus Symbiodinium (Symbiodinium sp.) within a widespread ranging scleractinian coral Galaxea fascicularis along latitudinal gradients in the South China Sea was examined using restriction fragment length polymorphism (RFLP) of the large subunit rDNA and sequencing. It revealed that G. fascicularis was associated with two distinct zooxanthellae clades. Galaxea fascicularis sampled in Daya bay in Guangdong province harboured Symbiodinium Clade C, while G. fascicularis sampled in Sanya Bay of Hainan Island, Yongxing Island of Xisha Islands, and Zhubi Reef of Nansha Islans harboured Symbiodinium Clade C and D either simultaneously or sequentially, indicating symbiosis flexibility. A distinct latitudinal distribution of Symbiodinium sp. in G. fascicularis was also revealed. Galaxea fascicularis hosting two clades of Symbiodinium sp., especially Symbiodinium clade D, may provide hosts with a flexible mechanism for adaptation to environmental change and can more easily survive mass coral bleaching events.

Diversity of free-living and symbiotic Symbiodinium in the coral reefs of Sanya, South China Sea

Abstract Unicellular photosynthetic dinoflagellates from the genus Symbiodinium are found either free-living or in hospite with a wide variety of marine invertebrate hosts including scleractinian corals. The linkages between free-living and endosymbiotic Symbiodinium remain largely unstudied and constitute a major gap in knowledge. In this study, the diversity of free-living Symbiodinium spp. and those associated with scleractinian corals from coral reefs in Sanya CRNR, South China Sea were determined by Symbiodinium-specific primers for the hypervariable region of the chloroplast 23S domain V (cp23S-HVR). The results illustrated that the free-living Symbiodinium spp. were highly spatially heterogeneous with high diversity related to clades A, B, C, D, F, G and H. However, the reef corals mainly hosted only one symbiont type of either clades C or D, and few species could harbour both concurrently. Surprisingly, Symbiodinium spp. in scleractinian corals were totally different from free-living forms in adjacent waters. These results suggest that the corals did not recruit Symbiodinium spp. from adjacent waters and the exchange of Symbiodinium spp. between corals and waters is limited in this region.

Can private management compensate the ineffective marine reserves in China

Marine reserves (MRs) have emerged as a preferred method to protect coral reefs from overfishing and human disturbance. However, due to ineffective enforcement by governments, many MRs have been reduced to mere “paper parks” which fail to achieve conservation goals. This is especially true in countries such as China where compliance is low and resources dedicated to enforcement may be scarce. Privately managed marine reserves (PMMRs) may be effective in areas where government enforcement is lacking. To determine if PMMRs are a viable alternative strategy to protect coral reefs, we surveyed and compared fish assemblages and coral coverage in national MRs in Sanya, China to areas of reef privately leased to and managed by dive operators and hospitality industries. We found higher fish abundances and fish sizes in PMMR sites than in MR sites. However, while PMMRs are protected from fishing, other human impacts such as marine debris and illegal coral collection were evident in most tourist sites. Despite protection, long-term monitoring data of PMMRs revealed that in recent years, fish abundances have slightly recovered but species richness has not, indicating the need for a more comprehensive coral reef management plan. We strongly recommend coupling PMMRs with expertise supported regulations as an alternative coral reef management strategy in China.