Dataset Information

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

ABSTRACT: Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or ? (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.

SUBMITTER: Jessen C

PROVIDER: S-EPMC3632597 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

Jessen Christian C Villa Lizcano Javier Felipe JF Bayer Till T Roder Cornelia C Aranda Manuel M Wild Christian C Voolstra Christian R CR

PloS one 20130422 4

Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acr ...[more]

PMID: 23630625

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Project description:Over the past several decades, corals worldwide have been affected by global warming, experiencing severe bleaching events that have often lead to coral death. The symbiotic Red Sea coral Stylophora pistillata is considered an opportunistic ‘r’ strategist, thriving in relatively unstable and unpredictable environments, and it is considered a stress-tolerant species. This study aimed to examine S. pistillata gene expression and to clarify the cellular pathways that are active during short-term heat stress caused by an increase from 24°C to 34°C over a 10-day period. Total RNA was extracted from heat-stressed coral fragments, labeled and hybridized against a designated S. pistillata custom microarray containing approximately 12,000 genes. Our results show that the heat stress reaction was sighted from 32°C and intensified significantly after 34°C treatment. Protein interaction networks of up- and down-regulated genes were constructed. The main clustering groups of up-regulated genes were ER stress and ER protein folding, cell cycle, ubiquitin-mediated proteolysis, cell death and cell death regulation and cellular stress response genes. These genes were enriched in cellular pathways related to the unfolded protein response (UPR) in the ER, ER-associated degradation (ERAD) and ubiquitin-mediated proteolysis. An analysis of the down-regulated genes yielded different clusters of genes related to extracellular matrix and actin organization, collagen, negative regulation of cell death and the Notch and Wnt signaling pathways. Genes encoding redox regulation proteins and molecular chaperones may be considered accurate “early warning genes”, while genes related to sensing and repairing DNA damage are severe heat-related genes. Here, we suggest that during short-term heat stress, S. pistillata might divert cellular energy into mechanisms such as UPR and ERAD at the expense of growth and biomineralization processes in an effort to recover from the stress.

Dataset Information

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

Publications

In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.

Similar Datasets

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