Status of Pigeon Island coral reef in Sri Lanka: a microbial perspective (original) (raw)

Microbiome of Sri Lankan Coral Reefs: An Indian Ocean Island Subjected to a Gradient of Natural and Anthropogenic Impacts

Oceans

Coral reefs around Sri Lanka have coexisted with human communities for thousands of years and are a continual source of food, economic productivity, and tourism. Although these reef systems sustain nearby populations, little is known about the presence or functional role of microbial communities on reefs dominated by hard corals or fleshy algae. Coral reef benthos cover was recorded, and reef-associated water samples were collected, sequenced and analyzed from seven coral reefs around Sri Lanka. Microbial metagenomes were analyzed to reveal both the taxonomic and metabolic makeup of the microbial communities present at each site. A metagenomic analysis of microbial phyla showed that Alphaproteobacteria and Gammaproteobacteria were most abundant, constituting up to 79.4% of microbial communities. At the order level, Rhodobacterales dominated the microbial communities across all sites, with the exception of the Paraviwella coral reef, where the order Alteromonadales dominated. A Princ...

Cross-Sectional Variations in Structure and Function of Coral Reef Microbiome With Local Anthropogenic Impacts on the Kenyan Coast of the Indian Ocean

Frontiers in Microbiology, 2021

Coral reefs face an increased number of environmental threats from anthropomorphic climate change and pollution from agriculture, industries and sewage. Because environmental changes lead to their compositional and functional shifts, coral reef microbial communities can serve as indicators of ecosystem impacts through development of rapid and inexpensive molecular monitoring tools. Little is known about coral reef microbial communities of the Western Indian Ocean (WIO). We compared taxonomic and functional diversity of microbial communities inhabiting near-coral seawater and sediments from Kenyan reefs exposed to varying impacts of human activities. Over 19,000 species (bacterial, viral and archaeal combined) and 4,500 clusters of orthologous groups of proteins (COGs) were annotated. The coral reefs showed variations in the relative abundances of ecologically significant taxa, especially copiotrophic bacteria and coliphages, corresponding to the magnitude of the neighboring human im...

European Journal of Phycology Factors influencing microbial mat composition, distribution and dinitrogen fixation in three western Indian Ocean coral reefs

European Journal of Phycology

2012): Factors influencing microbial mat composition, distribution and dinitrogen fixation in three western Indian Ocean coral reefs, European Journal of Phycology, 47:1, 51-66 This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

Biophysical and physiological causes of coral reef microbialization

2018

Coral reefs are declining globally as their primary producer communities shift from stony coral to fleshy macroalgae dominance. Previously, we have shown that the rise of fleshy macroalgae produces dissolved organic carbon (DOC) that lead to microbialization and coral death. Here we test the hypothesis that the biophysical cause of bacterial biomass accumulation is a relative decrease in electron acceptors relative to electron donors due to O2loss from macroalgae. We show that 37 % of photosynthetic O2produced by reef fleshy macroalgae is lost in the form of gas through ebullition from algae surfaces. O2loss increases DOC:O2ratios, decoupling the photosynthetically fixed carbon from oxidative potential for respiration. This biogeochemical environment drives heterotrophic microbes to increase cell-specific DOC consumption and cell sizes, accumulating biomass. In contrast, corals do not lose oxygen and support the growth of smaller and fewer bacteria.In situbiomass and metagenomic ana...

Disease prevalence and bacterial diversity in stony corals

2019

Coral reefs are globally one of the most threatened ecosystems, both from natural as well as anthropogenic pressures. The Indian coastline harbours around 1% of the global reef area, which form an important part of our natural resource endowment, and are of high priority for conservation and management. Despite their usefulness, coral reefs are being degraded by destructive anthropogenic activities and natural causes such as competition, predation, diseases and bleaching. Coral disease is a rising problem within all reef areas in India which can cause significant changes in reproduction, growth, community structure, species diversity of corals and many reef associated organisms. Environmental stressors including elevated sea surface temperature, ocean acidification, variations in salinity, water quality depletion, increased pollution loads, sedimentation and eutrophication lead to incidence of diseases in corals and associated fauna. The coral bleaching and mortality event that occu...