The stable isotope ratios of nitrogen(δ^(15)N) and carbon(δ^(13)C) were applied in this study to analyze sediment carbon sources and primary food sources of epifauna in an oceanic mangrove forest in tropical North S...The stable isotope ratios of nitrogen(δ^(15)N) and carbon(δ^(13)C) were applied in this study to analyze sediment carbon sources and primary food sources of epifauna in an oceanic mangrove forest in tropical North Sulawesi, Indonesia. Proportional contribution of mangrove-derived carbon to the food sources was compared among epifauna belonging to different feeding guilds. The sediment in the mangrove site with a depleted δ^(13)C signature(-28.02‰± 0.24‰) mainly consists of mangrove-derived carbon. Analysis using Bayesian stable isotope mixing model in the R program shows that mangrove-derived carbon can dominate the food sources of a majority of the epifauna(11 out of the total 18 species), especially 2 sesarmid crabs Parasesarma semperi and Sesarma sp., crab Epixanthus dentatus, and snails Terebralia sulcata and Optediceros breviculum, which belong to various feeding guilds. Mangrove-derived carbon has a proportional contribution to the food sources of fiddle crab Tubuca coarctata and 3 littorinid snails(Littoraria spp.) close to that of suspended particulate organic matter. Three planktophagous bivalve species(Anadara antiquata, Anadara sp. and Callista erycina) were found to mainly feed on seagrass-derived materials. Mean proportional contributions of mangrove-derived carbon to the food sources were 50.15%, 59.60%, 46.20% and 27.58% for the carnivorous, omnivorous, phytophagous and planktophagous groups, respectively. The results suggest that mangrove-derived carbon can directly(via grazing plant tissues) or indirectly(via deposit feedings) make an important contribution to the food sources of epifauna in the oceanic mangrove forest where the allochthonous input of organic carbon is low.展开更多
Herbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Macroalgae host abundant and diverse epibiont communities, the dynamics of which tend to ...Herbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Macroalgae host abundant and diverse epibiont communities, the dynamics of which tend to be mostly unknown in space and time. As the cultivation of macroalgae gains momentum worldwide, it is key to measure how epibionts could affect algal performance. We examined the epibiont community associated with farmed Alsidium triquetrum, a red macroalga with growing pharmacological interest. Measurements were conducted over two independent 60-day periods, one in summer and one in winter. Epibionts showed different patterns of succession in both seasons. Crustaceans, mainly amphipods, showed the highest overall density, with deleterious effects on daily growth rates of A. triquetrum in winter. Adverse effects as a function of epibionts were not detected in summer. A. triquetrum is a perennial alga. However, its performance as a crop in the nearshore can be significantly affected by the epibiont community structure that persists in winter. Amphipods and ascoglossan molluscs were risk factors in the mariculture of this agarophyte. In winter, they can destroy plants when they reach more than five individuals per gram of fresh biomass. Results highlight that commercial farming of A. triquetrum would be successful if grown throughout the summer.展开更多
基金supported by the National Key Technologies Research and Development Program of China (No. 2017YFC0506101)the China-ASEAN Maritime Fund ‘Monitoring and Conservation of the Coastal Ecosystems in the South China Sea’the National Natural Science Foundation of China (No. 31101876)。
文摘The stable isotope ratios of nitrogen(δ^(15)N) and carbon(δ^(13)C) were applied in this study to analyze sediment carbon sources and primary food sources of epifauna in an oceanic mangrove forest in tropical North Sulawesi, Indonesia. Proportional contribution of mangrove-derived carbon to the food sources was compared among epifauna belonging to different feeding guilds. The sediment in the mangrove site with a depleted δ^(13)C signature(-28.02‰± 0.24‰) mainly consists of mangrove-derived carbon. Analysis using Bayesian stable isotope mixing model in the R program shows that mangrove-derived carbon can dominate the food sources of a majority of the epifauna(11 out of the total 18 species), especially 2 sesarmid crabs Parasesarma semperi and Sesarma sp., crab Epixanthus dentatus, and snails Terebralia sulcata and Optediceros breviculum, which belong to various feeding guilds. Mangrove-derived carbon has a proportional contribution to the food sources of fiddle crab Tubuca coarctata and 3 littorinid snails(Littoraria spp.) close to that of suspended particulate organic matter. Three planktophagous bivalve species(Anadara antiquata, Anadara sp. and Callista erycina) were found to mainly feed on seagrass-derived materials. Mean proportional contributions of mangrove-derived carbon to the food sources were 50.15%, 59.60%, 46.20% and 27.58% for the carnivorous, omnivorous, phytophagous and planktophagous groups, respectively. The results suggest that mangrove-derived carbon can directly(via grazing plant tissues) or indirectly(via deposit feedings) make an important contribution to the food sources of epifauna in the oceanic mangrove forest where the allochthonous input of organic carbon is low.
文摘Herbivores can drastically alter the morphology of macroalgae by directly consuming tissue and by inflicting structural wounds. Macroalgae host abundant and diverse epibiont communities, the dynamics of which tend to be mostly unknown in space and time. As the cultivation of macroalgae gains momentum worldwide, it is key to measure how epibionts could affect algal performance. We examined the epibiont community associated with farmed Alsidium triquetrum, a red macroalga with growing pharmacological interest. Measurements were conducted over two independent 60-day periods, one in summer and one in winter. Epibionts showed different patterns of succession in both seasons. Crustaceans, mainly amphipods, showed the highest overall density, with deleterious effects on daily growth rates of A. triquetrum in winter. Adverse effects as a function of epibionts were not detected in summer. A. triquetrum is a perennial alga. However, its performance as a crop in the nearshore can be significantly affected by the epibiont community structure that persists in winter. Amphipods and ascoglossan molluscs were risk factors in the mariculture of this agarophyte. In winter, they can destroy plants when they reach more than five individuals per gram of fresh biomass. Results highlight that commercial farming of A. triquetrum would be successful if grown throughout the summer.
