珊瑚与虫黄藻

Strategy for Ecosystem Symbiosis and Coexistence with Humans under Multiple Stresses
Coral Reef Science
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Fig. 1 Multiple scales of symbiotic system among coral-algal symbionts, coral reefs and humans
Fig. 8 A photo showing differential bleaching susceptibility of adjacent colonies of Porites randalli in the Ofu back reef in American Samoa. Bleaching is commonly patchy across a reef and bleached and unbleached colonies are often observed in close proximity. Whether this variability is caused by adaptation or acclimatization of the host or Symbiodinium remains to be determined
Fig. 2 Degradation of the coral reef symbiotic system by global and local human stressors
Fig. 3 Coral-reef scenes in the mid-1970s. As quoted in Jackson (2014), Sylvia Earle noted in 1972 that “. . .tropical reefs, notable for their dazzling profusion of animal life, are almost devoid of conspicuous plants”. Bruno et al. (2014) found that in natural undisturbed baseline conditions, benthic algae is patchily distributed and can occupy up to 10–30% of the substratum, averaging 22%. Clockwise from upper left: Ucubsui Reef, San Blas Islands, Caribbean Panama; Islas Secas, Pacific Panama; Arekabesan Island, Palau; Aunu’u Island, American Samoa; also Aunu’u. These are not a random selection of photographs, but were selected to show how easy it was to be impressed with the prevalence of animal tissue in the 1970s. Odum and Odum (1955) argued that many, if not most, of the algae were endolithic and out of sight
Fig. 4 A Caribbean boring sponge (Cliona cf caribbea) covering and eroding several square meters of reef substrate, San Blas, Panama, 3 m depth (30 June 1993). Arrows denote perimeter of sponge patch
Fig. 5 Reproductive modes of scleractinian corals. Upper: spawning coral releasing egg– sperm bundles. Lower: brooding coral releasing planula larva (Illustration by Dwi Haryanti)
Fig. 6 Types of zooxanthellae observed in coral tissue. (a, b) Healthy cells with a spherical shape and expanded chloroplast. (c, d) Shrunken, darkly colored cells with reduced sizes and partially fragmented chloroplasts. (e) Bleached cells with pale and colorless chloroplasts. (f) Three categories of zooxanthellae. (g) White light micrograph and (h) fluorescence image of healthy and shrunken cells (shrunken cells are indicated by arrowheads)
Fig. 9 Molecular analyses have had a profound impact on our understanding of evolutionary relationships of many coral reef organisms, including corals. Kitahara et al. (2010, tree above from Fig. 1), in a recent comprehensive phylogenetic analysis of scleractinian corals, showed that deep-sea azooxanthellate species are basal to the group and most recognized shallow-water zooxanthellate families are polyphyletic. In some cases, Atlantic and Pacific species once thought to belong to the same genus, are now placed in different families, such as Homophyllia (formerly Scolymia) australis from the Pacific (Lobophylliidae, left image) and Scolymia cubensis from the Atlantic (Mussidae, right image) (Photos courtesy of JEN Veron)
Fig. 7 New concept of coral bleaching revealed from counting and observation of zooxanthellae
Fig. 8 Highthroughput RNA sequencing is increasingly used as a tool to understand the physiological response of corals to stressors. Libro et al. (2013, above from Figs. 1 and 2) investigated the immune response of Acropora cervicornis to White-Band Disease (upper photo) by comparing RNAseq profiles of healthy and infected tissues. Their approach identified a series up- and downregulated genes that repre- sent 4 % of the coral transcriptome (plotted in red below)