Grevo S. Gerung

Cultivation of tropical red seaweeds in the BIMP-EAGA region

The Brunei–Indonesia–Malaysia–Philippines East Asia Growth Area (BIMP-EAGA) is located within the Coral Triangle, known to have the world’s richest biodiversity in marine flora and fauna. This region lies within the 10° N and 10° S of the Equator where natural populations of both Kappaphycus and Eucheuma grow luxuriantly and abundantly. It is in this same region where commercial cultivation of Kappaphycus and Eucheuma began in the Philippines around the mid-1960s. Commercial farming of Kappaphycus (which was originally called Eucheuma) was successful in the Philippines from the early 1970s, after which the technology was transferred to Indonesia and Malaysia in the late 1970s. No seaweed cultivation has been reported in Brunei. At present, carrageenophytes are cultivated in sub-tropical to tropical countries circumferentially around the globe within the 10° N and S of the Equator. However, their combined production is still low as compared to Indonesia, the Philippines, and Malaysia. Notably, few improvements in farming techniques have been made since its first introduction. Some of the major improvements were the introduction of deep-water farming using hanging long lines, multiple rafts, and spider webs in the Philippines; the use of short and long ‘loops’, instead of plastic ‘tie-tie’ in Indonesia; and mechanization in harvesting and use of solar “greenhouse” drying in Malaysia. Commercial cultivation of tropical red seaweeds in the BIMP-EAGA region is dominated by Kappaphycus and Eucheuma (carrageenophytes) and Gracilaria (agarophytes) and the area became the major region for the production of carageenophytes and agarophytes globally. In particular, Indonesia is a major center for the production of Gracilaria. There is an increasing demand for other agarophytes/carrageenophytes in the international market such as Gelidium spp., Pterocladia spp., Porphyroglossum sp., and Ptilophora sp. for paper and ethanol production in Indonesia and Malaysia, and Halymenia for phycoerythrin pigments in the Philippines currently pursued in an experimental stage. A summary of the present status, problems, sustainability, and challenges for the cultivation of tropical red seaweeds in the BIMP-EAGA region are discussed in this paper.

Homogeneous population of the brown alga Sargassum polycystum in Southeast Asia: possible role of recent expansion and asexual propagation.

Southeast Asia has been known as one of the biodiversity hotspots in the world. Repeated glacial cycles during Pleistocene were believed to cause isolation of marine taxa in refugia, resulting in diversification among lineages. Recently, ocean current was also found to be another factor affecting gene flow by restricting larval dispersal in animals. Macroalgae are unique in having mode of reproduction that differs from that of animals. Our study on the phylogeographical pattern of the brown macroalga Sargassum polycystum using nuclear Internal Transcribed Spacer 2 (ITS2), plastidal RuBisCO spacer (Rub spacer) and mitochondrial cytochrome oxidase subunit-III (Cox3) as molecular markers revealed genetic homogeneity across 27 sites in Southeast Asia and western Pacific, in sharp contrast to that revealed from most animal studies. Our data suggested that S. polycystum persisted in single refugium during Pleistocene in a panmixia pattern. Expansion occurred more recently after the Last Glacial Maximum and recolonization of the newly flooded Sunda Shelf could have involved asexual propagation of the species. High dispersal ability through floating fronds carrying developing germlings may also contribute to the low genetic diversity of the species.

Transfer of the red alga Gelidium zollingeri Sonder (Gelidiales) to Yonagunia (Halymeniales) based on morphological and molecular evidence

Boo G.H, Park J.K., Gerung G.S. and Boo S.M. 2013. Transfer of the red alga Gelidium zollingeri Sonder (Gelidiales) to Yonagunia (Halymeniales) based on morphological and molecular evidence. Phycologia 52: 279–287. DOI: 10.2216/12–092.1 An examination of the type specimen of Gelidium zollingeri Sonder showed that it was incorrectly placed in Gelidium. To determine the appropriate taxonomic position, we undertook a detailed morphological examination of the holotype (National Herbarium of Victoria, Australia) as well as fresh materials collected from Sempu, the type locality, and a surrounding location Kondang Merak in Malang city, East Jawa, Indonesia. In our collections we found tetrasporangia and carposporophytes on female thalli. The vegetative and reproductive structures clearly placed it in the Halymeniales. Four sequences of rbcL and cox1, two each from Sempu and Kondang Merak, were identical. Our analysis of rbcL sequences showed that G. zollingeri formed a monophyletic clade with the two known Yonagunia species, Y. formosana and Y. tenuifolia. Consequently, we proposed the new combination, Yonagunia zollingeri, based on Gelidium zollingeri. Yonagunia zollingeri was characterized by a cartilaginous, flattened thallus that was subcostate in lower parts, with cystocarpic leaflets that arose on terminal branchlets and round to heart-shaped tetrasporangial leaflets. Yonagunia is now known to occur in Indonesia, Japan (Okinawa), Malaysia, Taiwan, and Vietnam.

Light and temperature effects on photosynthetic activity of E ucheuma denticulatum and K appaphycus alvarezii (brown and green color morphotypes) from Sulawesi Utara, Indonesia

Knowledge concerning the effects of several abiotic factors on the physiology of carrageenophytes is essential both in ecological and economic standpoints, to ensure their sufficient supply for the sustainability of seaweed‐based industries. This paper presents the photosynthetic characteristics of farmed carrageenophytes, E ucheuma denticulatum and K appaphycus alvarezii [brown (BRN) and green (GRN) color morphotypes] from Sulawesi Utara (Sulawesi Island), Indonesia, as determined by examining their photosynthetic response across different temperatures and irradiances using dissolved oxygen measurements and pulse‐amplitude modulated fluorometer. Net photosynthesis–irradiance ( P – E ) curves at 26°C revealed that net photosynthetic rates of the three seaweeds gradually increased until the estimated saturation irradiances ( E k ) of 58 μmol photons m− 2 s−1 (49–68 μmol photons m− 2 s−1, 95% Bayesian prediction intervals; BPI) for E . denticulatum, and 158 and 143 μmol photons m− 2 s−1 (134–185 and 99–203 μmol photons m− 2 s−1, 95% BPI) for BRN and GRN K . alvarezii, respectively; and that no photoinhibition was observed at the highest irradiance of 1000 μmol photons m− 2 s−1. All seaweed samples exhibited photosynthetic tolerance to high PAR as shown by their recovery in maximum quantum yields (Fv / Fm ) following chronic exposures; as well as tolerance over a broad range of temperature, which is from 19 to 33°C for E . denticulatum, 20–29°C for BRN K . alvarezii, and 17–32°C for GRN K . alvarezii. Temperature responses of these carrageenophytes indicated that they were well‐adapted to the annual seawater temperatures in the cultivation site; however, they are also likely close to threshold levels for thermal inhibition, given the decline in Fv / Fm above 30°C.

Mesospora elongata sp. nov. (Ralfsiales, Phaeophyceae), a new crustose brown algal species from the Indo-Pacific region

Poong S.-W., Lim P.-E., Phang S.-M., Gerung G.S., and Kawai H. 2013. Mesospora elongata sp. nov. (Ralfsiales, Phaeophyceae), a new crustose brown algal species from the Indo-Pacific region. Phycologia 52: 74–81. DOI: 10.2216/12-42.1 Crustose brown algae have relatively simple morphology and anatomy, and the limited characters were a major obstacle in delineating species of Mesospora (Ralfsiales, Phaeophyceae). The type species, Mesospora schmidtii, was described using material collected in Indonesia. A subsequent study, using material from Japan, was identified as M. schmidtii, but we questioned the identity. Therefore, we analyzed morphological characters as well as the plastid-encoded RuBisCO large subunit (rbcL) and mitochondrial-encoded cytochrome c oxidase subunit 1 (cox1) genes using new material obtained from the type locality (Indonesia) and new material obtained from Japan. The molecular phylogenetic analysis distinguished two clades, one representing material from the type location and the other representing an undescribed species from Japan. Therefore, we described Mesospora elongata sp. nov. to encompass the Japanese material. Morphologically, the two species were very similar (i.e. cryptic species); the only obvious difference was the number of cells. We also discussed Hapalospongidion but we concluded that Mesospora should be a distinct genus based on morphology; gene sequence data will be required for Hapalospongidion before the relationship of the two genera is more thoroughly resolved.

Impacts of Climate change on Eucheuma-Kappaphycus Farming

Climate change impacts all forms of life – including seaweeds! For farmed Eucheuma/Kappaphycus the direct and indirect impacts have caused not only physical damage to the crops but has also affected the eco-physiological, reproductive and metabolic processes of the seaweed. As a result of their importance as sources of different types of carrageenan, Eucheuma (iota)/Kappaphycus (kappa) have spread, through facilitated transfer, from its original tropical farming sites in the Philippines, across several localities in the Pacific, Atlantic and Indian Oceans. Ocean warming has caused the ‘tropicalization’ of sub-tropical waters of northeast Asia and South America, and more areas are becoming increasingly conducive to Eucheuma/Kappaphycus farming. Increases in surface seawater temperatures could have deleterious effects on reproductive capacity, including spore production, germination, recruitment and growth which, coupled with the long-practiced clonal propagation, have resulted in the declining productivity and quality of extracted colloids. Global climate change and anomalous climatic events such as El Nino and La Nina have increased the susceptibility of the selected cultivars of farmed eucheumatoids to bacterial pathogens as a result of stressful abiotic conditions which are conducive to ‘ice-ice’ disease and damaging impacts of epiphytism which have combined and literally wiped out activity in some farms. Typhoons and storms, as well as heavy rainfall during the wet season, increased in intensity by climate change, have also destroyed farms resulting in the loss of investments and income for those workers dependent on seaweed cultivation as a cash generating activity.