Seagrass and mangroves support a number of ecosystem services, such as sustaining marine fisheries, water clarity, and the protection of shoreline from erosion. Producing a national and global consensus of their total worth is a challenge. More often than not the variety and distal evaluation approaches do not fit comfortably within current market-based economic models, which are arguably more capable of swaying government policy in assessing their preservation over economic development. The exception to this rule is the increasing recognition of the importance of these systems as a carbon sink for combating ‘greenhouse’ gas emissions. In response, these sinks have been labelled as ‘Blue Carbon, a rhetorical tool to distinguish them from terrestrial and ocean sinks, and the different approaches they would require for conservation. However, there are a number of knowledge gaps, untested underlying assumptions, and measurement practicalities in assessing an accurate value of carbon sequestration and storage. Unless these are addressed, then the push for seagrass and mangroves to be included within the carbon-financing network may not be successful. This short communication discusses the limitations of the current blue carbon conceptual model, and provides recommendations for a more limited but robust submission of its present and future worth, required for carbon financing.
Seagrasses provide a range of marine ecosystem services. These include coastal protection, biodiversity, provision of food for various organisms, breeding and nursery habitats for many marine species, and carbon storage. Increasing anthropogenic pressures have contributed to the decline of seagrass habitats. Transplantation is one of the solutions to increase seagrass coverage and resilience. What is often overlooked, however, is the ability of this tropical ecosystem to attract and support faunal assemblages that may impinge on the success of the transplantation. A pilot study on seagrass transplantation at Gaya Island (Kota Kinabalu, Sabah) was intended for observing its stability and species of fauna that develop association with this vegetation. The study covered the southwest and northeast monsoons. Mixed seagrass species were planted on approximately 50% of 30 m 2 transplantation areas. Monitoring of the planted seagrass was carried out in five phases (T1-T5) from September 2016 to April 2018. Weekly observations were made by SCUBA diving. Identification of associated fauna was done on the spot and was based on morphological characteristics. During the T1 (September to December 2016) the seagrass coverage was reduced to 41% due to strong waves generated by the northeast monsoon. However, the seagrass coverage increased ( 66 %) during the southwest monsoon (T2 - T4) in 2017. In early 2018 (T5), the seagrass coverage again reduced (about 18%) due to strong waves but recovered again at the end of the monitoring period (April 2018). A total of 30 species of fauna that were identified consisted of 9 resident and 21 non-resident species. Physical structure of transplanted seagrass created a microhabitat, and increased the food availability and abundance, which attracted many species of different trophic levels.
Shipworms (family Teredinidae) are specialized bivalves that bore into the submerged wooden structures and mangrove trees, except genus Zachsia which is associated with seagrass rhizome. However, only one species has been described, located in Russian, Korean and Japanese waters and associated only with genera Phyllospadix and Zostera. Potentially wider distributions and even new species within this group have not been reported from another bioregion. Given the potential impacts on seagrass health, it is important to ascertain if the distribution of Zachsia extends across other climatic regions and seagrass species. In response, a study was conducted in a seagrass meadow at Gaya Island (Sabah, Malaysia). A total of 900 seagrass shoots were randomly excavated from a mixed seagrass bed of Enhalus acoroides, Cymodocea rotundata and C. serrulata. It was found that Zachsia sp. was present within the rhizomes of E. acoroides and C. rotundata, with an occupancy of around 12% occupancy (n=100) and 1% (n=400), respectively. A post-mortem examination indicated that the bivalve appeared to have ingested most of the rhizome’s internal tissues, leaving behind a calcareous hollow tube. Furthermore, this apparent infestation appeared to significantly reduce shoot growth by around 70% from 0.738±0.036 to 0.220±0.038 cm day-1. This finding may be significant, as it suggests, for the first time, that the rhizome parasitism is another possible vector in controlling seagrass growth and mortality. Further investigations are required to determine if this boring bivalve is indeed a new species, its distribution in other tropical areas and its role in the ecosystem.
Fin whales are a cosmopolitan species found in the largest water masses of the world. In Malaysia, as well as other tropical countries in the Southeast Asian region, literature on fin whales is limited, and as a result, there is confusion regarding their distribution range in the region. This study utilizes the fresh tissue of the skin and blubber of a dead fin whale that was stranded in Sabah (Borneo, Malaysia) on the coast of the South China Sea to confirm the species identity, possible properties of the species' diet, and any trace element contamination. The DNA profile results confirmed that the whale belonged to Balaenoptera physalus. Further investigation of its cytochrome b gene sequence indicated that it was closely related to the southern fin whale (Balaenoptera physalus quoyi). This finding indicates that fin whales indeed migrate to warm tropical waters and that their continuous global distribution spans the equatorial region. The dominant fatty acids, such as C18:0, C16:1, C18:1N9T and C16:0 profiles, were consistent with the pelagic plankton diet that the whale would have had during its migration in the tropical waters of the South China Sea. The whales are likely pelagic feeders and thus need to be offshore, which would explain why they are rarely seen in shallow coastal areas during migration in these waters. The concentrations of K, Ca, Sc, Mg and Al ranged from 0.45 μg g-1 to 7.80 μg g-1, while Cr, Cd, As and Pb were either very low or could not be detected. This is consistent with concentrations of trace elements previously reported for other baleen whale genera from the Southern Ocean. Our study demonstrates the importance of the South China Sea as a migration route for the southern fin whale, since it is a rich food source with relatively low contaminant levels. The South China Sea is therefore well-suited to ensure these whales' survival during migration.