Quantitative and qualitative analyses of dissolved organic matter released from Ecklonia cava Kjellman, in Oura Bay, Shimoda, Izu Peninsula, Japan

Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages

“…Information on the composition of DCNS within algal exudates can reveal information about the origin and macromolecular structure of a particular polysaccharide (Percival, 1979;Chattopadhyay et al, 2010;Anastasakis et al, 2011), the physiological status of the algae at the time when the exudate was harvested , or the exoenzymatic activity of the ambient community of heterotrophic bacterioplankton (Arnosti, 2011). The significant enrichment in the mole % of fucose in the Turbinaria treatment is consistent with studies assessing the sugars in other Turbinaria species (Chattopadhyay et al, 2010) and other brown algae (Percival, 1979;Anastasakis et al, 2011), as well as in brown algal DOM exudates (Wada et al, 2007). Fucoidan is produced by Turbinaria in the cell wall to protect against desiccation (Percival, 1979;Anastasakis et al, 2011) and is a rather large macromolecule (B50 kDa; Chattopadhyay et al 2010).…”

“…It is important to note that physiological stress due to nutrient limitation (Karl et al, 1998) or the transition between nutrient replete to nutrient deplete phases (Smith et al, 1998;Carlson, 2002) can trigger the release of DOM by phytoplankton. However, DOM release from macroalgae in nutrient replete coastal systems is also well documented (Wada et al, 2007;Chattopadhyay et al, 2010;Haas and Wild, 2010). Relative to the macroalgae, the exudates from the hermatypic coral Porites and the calcareous macroalga Halimeda were dominated by galactose, glucose and mannose þ xylose, much like the composition of ambient seawater (Figures 1a and b; Table 1).…”

“…In the present study, we show that DCNS comprise upwards of 50% of coral exudates and a smaller but still significant fraction of macroalgal exudates (8-33%; Table 3). The DCNS fraction of DOC is clearly not the only material exuded by algae and coral, as uronic acids, proteins, amino sugars and lipids have all been detected in the tissue and DOM of algae (Percival, 1979;Jensen, 1993;Aluwihare and Repeta, 1999;Wada et al, 2007;Anastasakis et al, 2011) and the tissue and mucus of coral (Meikle et al, 1988;Coffroth, 1990;Wild et al, 2010). However, the composition of the exuded DCNS did differentiate the four exudates from both experimental controls and the ambient waters (Figure 1a), and portions of the DCNS pool were preferentially and differentially utilized by bacterioplankton among the treatments (Figures 1c and d; Tables 2 and 3), suggesting that it is a meaningful proxy for differences in the overall character of the DOM exuded by benthic macroorganisms on coral reefs.…”

The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts

“…Algal-derived detritus is nutritious and targeted by many tropical herbivorous fishes [62]. Temperature-mediated increases in dissolved organic matter [63] and bacterial activity [64] should increase production of particulate organic matter, resulting in more amorphous and highly nutritious detritus on temperate reefs. The movement and persistence of tropical herbivores into temperate reefs may therefore be facilitated by enhanced nutritional quality of detritus in these systems.…”

Application of Gas Chromatography to Exuded Organic Matter Derived from Macroalgae

“…Although a half of the products constitute the organic matter of algal body (Hatcher et al, 1977), considerable part of them would be exuded and dissolved into ambient seawater (Khailov & Burlakova, 1969;Sieburth, 1969;Hatcher et al, 1977;Abdullah & Fredriksen, 2004;Wada et al, 2007). The organic materials released into ambient seawater induces some alteration of marine and atmospheric environments.…”