Seaweed aquaculture beds (SABs) that support the production of seaweed and their diverse products, cover extensive coastal areas, especially in the Asian-Pacific region, and provide many ecosystem services such as nutrient removal and CO 2 assimilation. The use of SABs in potential carbon dioxide (CO 2 ) mitigation efforts has been proposed with commercial seaweed production in China, India, Indonesia, Japan, Malaysia, Philippines, Republic of Korea, Thailand, and Vietnam, and is at a nascent stage in Australia and New Zealand. We attempted to consider the total annual potential of SABs to drawdown and fix anthropogenic CO 2 . In the last decade, seaweed production has increased tremendously in the Asian-Pacific region. In 2014, the total annual production of Asian-Pacific SABs surpassed 2.61 × 10 6 t dw. Total carbon accumulated annually was more than 0.78 × 10 6 t y −1 , equivalent to over 2.87 × 10 6 t CO 2 y −1 . By increasing the area available for SABs, biomass production, carbon accumulation, and CO 2 drawdown can be enhanced. The conversion of biomass to biofuel can reduce the use of fossil fuels and provide additional mitigation of CO 2 emissions. Contributions

The effects of herbivory and the season of disturbance on species composition and algal succession were experimentally tested at a tropical intertidal shore, Phuket Island, Thailand. Dead coral patches were cleared of all organisms during both the dry and rainy seasons in order to study the effects of season on algal succession and cages were set up to exclude fish herbivory. Algal succession in this intertidal habitat showed a simple pattern and took a year from the early Ulva paradoxa C. Agardh stage to the late Polysiphonia sphaerocarpa Børgesen stage. The abundance of algae during succession was under the influence of seasonal change. U. paradoxa reproduced and recruited throughout the year. Caging effects did not apparently influence algal abundance, perhaps because resident herbivorous damselfishes excluded other herbivores from their territories and maintained their algal "farms". Unexpectedly, the percent cover of Ulva in the caged plots was lower than in uncaged plots. This pattern may indicate that caging excluded damselfishes only, but allowed small herbivores that consumed substantial amounts of soft filamentous algae in the cages.

Halimeda is a potential carbon sink species and an important player in the global carbonate budget. The objectives of this study were to: (i) examine the CaCO 3 and sediment productions of H. macroloba by measuring the density, growth rate, and recruitment; (ii) quantify the numbers of aragonite crystals; (iii) document reproductive events; and (iv) determine the lifespan. This study was carried out at Lidee Lek Island, Satun, Thailand during July 2015 to April 2016. The density was measured using quadrats (0.25 m 2 ) and three 50 m line transects. Alizarin Red-S marking technique was used for the growth rate and CaCO 3 accumulation rate assessments. The recruitment, reproduction and life-span were measured by tagging 500 individuals. Tagged individuals and new plants were counted. In this study, mean and the highest density of Halimeda were 44.42 AE 13.95 and 138.22 AE 11.68 thalli m −2 , respectively, and Halimeda produced 1-2 new segments.thallus −1 day −1 or 0.021 AE 0.001 g dry weight.thallus −1 .day −1 . The annual biomass production was 1910-5950 g m −2 year. −1 . There was a low rate of occurrence of sexual reproduction, observed in late July to September, ranging from 0.17% to 1.92%. For the mortality and recruitment rates, approximately 70-80% of individuals were lost during July to September 2015, probably from sexual reproduction and the recruitment rate varied from 5.36 AE 0.79% to 21.03 AE 2.33%. The highest density of new recruits was found in September 2015 right after the sexual reproductive event occurred. New recruits have been found up to April 2016 without any reproductive events, suggesting that both sexual and asexual reproduction helped maintain the population. The life span of Halimeda was 8-12 months. In addition, Halimeda accumulated CaCO 3 at approximately 0.018 g CaCO 3 thallus −1 day −1 and produced CaCO 3 at approximately 291.94-908.11 g m −2 year −1 , indicating that Halimeda contributes to CaCO 3 and helps to sink carbon through calcification. The results in terms of the density, growth rate, and CaCO 3 accumulation rate can be used to calculate the mass of carbonate sediment contributed by Halimeda.

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