Coral-associated bacteria play critical roles in the regulation of coral health and function. Environmental perturbations that alter the bacterial community structure can render the coral holobiont more susceptible and less resilient to disease. Understanding the natural variation of the coral microbiome across space and host species provides a baseline that can be used to distinguish shifts in community structure. Using a 16S rRNA gene metabarcoding approach, this study examines bacterial community structure across three scleractinian coral hosts. Our results show that corals of three regions-eastern and western Peninsular Malaysia and Singapore-host distinct bacterial communities; despite these differences, we were able to identify a core microbiome shared across all three species. This core microbiome was also present in samples previously collected in Thailand, suggesting that these core microbes play an important role in promoting and maintaining host health. For example, several have been identified as dimethylsulfoniopropionate (DMSP) metabolizers that have roles in sulfur cycling and the suppression of bacterial pathogens. Pachyseris speciosa has the most variable microbiome, followed by Porites lutea, with the composition of the Diploastrea heliopora microbiome the least variable throughout all locations. Microbial taxa associated with each region or site are likely shaped by local environmental conditions. Taken together, host identity is a major driver of differences in microbial community structure, while environmental heterogeneity shapes communities at finer scales.
We present a comprehensive checklist of scleractinian (hard) corals for the Mersing Islands, Malaysia based on surveys conducted at 24 reefs across protected and unprotected marine areas. A total of 261 species of corals from 16 families and one incertae sedis (Pachyseris spp.) were recorded, along with ten records that are new for the east coast of Peninsular Malaysia. Compared against the IUCN Red List, 46.7% of coral species found in the Mersing Islands were of Least Concern (LC), 29.5% as Near Threatened (NT) and 16.4% Vulnerable (V). Only one recorded species, Pectiniamaxima (Moll & Best, 1984), was listed as Endangered (EN). Baseline species diversity data are essential for the monitoring and management of marine biodiversity, especially within marine protected areas. With both protected and unprotected coral reef areas in the vicinity of the widely scattered Mersing Islands, the diversity and distribution of coral species can be used as the basis for area-based conservation and management strategies. The diversity and abundance of scleractinian corals of each island or area should be surveyed periodically to ensure the appropriate level of protection is afforded to retain scleractinian biodiversity in this region.
ABSTRACT
Polyaniline (PANI) and Kronos C doped Titanium dioxide (TiO2) was fabricated as PANI/TiO2
solar cell and reported on its simple photovoltaic performance detected by using voltameter and
tested for stability for 12 months. The PANI and TiO2 were coated onto different indium tin oxide
(ITO) glass plates by using a drop-casting method and sandwich attached for simple solar cell
preparation. PT4 sample was the optimum solar cell with 0.2: 0.2 g of PANI: TiO2 ratio under 2
cm2 surface area based on the highest voltage produces from 100 mW cm-1
of light intensity metal
highlight lamp. No voltage was detected for PT7 where the single layer TiO2 coated without PANI
attached for solar cell system using same fabrication. It shows that PANI has a significant role in
functionalizing the photovoltaic system. The C-N stretching of aromatic amine and C-N stretching
for the benzenoid at peaks of 1222 and 1166 cm-1
respectively in FTIR spectra has confirmed the
PANI structure supported by an XRD pattern. TP4 has the highest photovoltaic performance
compared to other types of TiO2 based on the electron lifetime (τe) and the voltage produced was
sustained up to 12 months.