Benthic Reef Primary Production in Response to Large Amplitude Internal Waves at the Similan Islands (Andaman Sea, Thailand)

Coral reefs are facing rapidly changing environments, but implications for reef ecosystem functioning and important services, such as productivity, are difficult to predict. Comparative investigations on coral reefs that are naturally exposed to differing environmental settings can provide essential information in this context. One prevalent phenomenon regularly introducing alterations in water chemistry into coral reefs are internal waves. This study therefore investigates the effect of large amplitude internal waves (LAIW) on primary productivity in coral reefs at the Similan Islands (Andaman Sea, Thailand). The LAIW-exposed west sides of the islands are subjected to sudden drops in water temperature accompanied by enhanced inorganic nutrient concentrations compared to the sheltered east. At the central island, Ko Miang, east and west reefs are only few hundred meters apart, but feature pronounced differences. On the west lower live coral cover (-38 %) coincides with higher turf algae cover (+64 %) and growth (+54 %) compared to the east side. Turf algae and the reef sand-associated microphytobenthos displayed similar chlorophyll a contents on both island sides, but under LAIW exposure, turf algae exhibited higher net photosynthesis (+23 %), whereas the microphytobenthos displayed reduced net and gross photosynthesis (-19 % and -26 %,respectively) accompanied by lower respiration (-42 %). In contrast, the predominant coral Porites lutea showed higher chlorophyll a tissues contents (+42 %) on the LAIW-exposed west in response to lower light availability and higher inorganic nutrient concentrations, but net photosynthesis was comparable for both sides. Turf algae were the major primary producers on the west side, whereas microphytobenthos dominated on the east. The overall primary production rate (comprising all main benthic primary producers) was similar on both island sides, which indicates high primary production variability under different environmental conditions

Pairwise population comparisons of <i>Aedes (Stegomyia) aegypti</i> (L.) from five villages in Chachoengsao Province, eastern Thailand.

<p>Upper diagonal shows pairwise <i>F</i>_ST estimates, lower diagonal shows pairwise geographic distance (km). Significance of <i>F</i>_ST estimates (obtained by 15300 permutations) at the indicative adjusted nominal level (5%) of <i>P</i><0.000327 is indicated by bold type.</p

Estimates of effective population size (<i>N</i>_e) of <i>Aedes (Stegomyia) aegypti</i> (L.) in five villages in Thailand based on Waples' [20] method using temporal differences in allele frequency across 9 generations.

<p>Estimates of effective population size (<i>N</i>_e) of <i>Aedes (Stegomyia) aegypti</i> (L.) in five villages in Thailand based on Waples' <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001913#pntd.0001913-Waples1" target="_blank">[20]</a> method using temporal differences in allele frequency across 9 generations.</p

Population characteristics of <i>Aedes (Stegomyia) aegypti</i> (L.) sampled from five villages in Chachoengsao Province, eastern Thailand (<i>r</i> = allelic richness, <i>F</i>_IS = inbreeding coefficient, <i>H</i>_E = expected heterozygosity, <i>H</i>_O = observed heterozygosity, HW-<i>P</i> = Hardy Weinberg <i>P</i> value, *significant after correction for multiple comparisons using False Discovery Rate procedures [12], N/S = no spatial autocorrelation at distances tested), Relatedness estimator [22], GGD = geographic distance.

<p>Population characteristics of <i>Aedes (Stegomyia) aegypti</i> (L.) sampled from five villages in Chachoengsao Province, eastern Thailand (<i>r</i> = allelic richness, <i>F</i>_IS = inbreeding coefficient, <i>H</i>_E = expected heterozygosity, <i>H</i>_O = observed heterozygosity, HW-<i>P</i> = Hardy Weinberg <i>P</i> value, *significant after correction for multiple comparisons using False Discovery Rate procedures <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001913#pntd.0001913-Goudet1" target="_blank">[12]</a>, N/S = no spatial autocorrelation at distances tested), Relatedness estimator <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001913#pntd.0001913-Waples2" target="_blank">[22]</a>, GGD = geographic distance.</p

Temporal differences in population structure in <i>Aedes (Stegomyia) aegypti</i> (L.) in a complex of five eastern Thai villages, identified with Factorial Correspondence Analysis ((A) Village 1; (B) Village 2; (C) Village 3; (D) Village 6 and (E) Village 11).

<p>Temporal differences in population structure in <i>Aedes (Stegomyia) aegypti</i> (L.) in a complex of five eastern Thai villages, identified with Factorial Correspondence Analysis ((A) Village 1; (B) Village 2; (C) Village 3; (D) Village 6 and (E) Village 11).</p