STUDY ON GIANT CLAMS (CARDIIDAE) POPULATION IN KEI KECIL WATERS, SOUTHEAST-MALUKU

Penelitian ini dilakukan untuk mengetahui komposisi dan kepadatan jenis, distribusi ukuran, serta kondisi habitat kima pada sembilan lokasi, yaitu Pulau Ohoimas, Dullah, Naam, Laguna Hoat, Warhu, Pasir Panjang,Ohoidertawun, Teluk Un, dan Tandusan, di perairan Kei Kecil. Pengambilan data dilakukan dengan menggunakan metode kuadrat-transek. Penilaian kondisi habitat mengacu pada tipe substrat yang berdasarkan kode bentik (benthic code). Hasil penelitian menunjukkan bahwa di perairan Kei Kecil terdapat enam jenis kima, yaitu T. crocea, T. squamosa, T. maxima, T. derasa, T. gigas, dan Hippopus hippopus. Secara keseluruhan kepadatan individu kima di Kei Kecil termasuk sangat rendah. Kima T. crocea adalah jenis yang paling dominan, sedangkan T. derasa dan T. gigas adalah jenis yang paling sedikit ditemukan. Berdasarkan distribusi panjang cangkang, individu yang berada pada fase juvenile jumlahnya lebih sedikit dibandingkan jumlah individu fase remaja dan dewasa. Habitat yang paling bagus di perairan Kei Kecil adalah Ohoimas dengan variasi substratnya dan kekayaan jenis yang tertinggi. Rekomendasi yang diberikan bagi pemerintah lokal dan masyarakat adalah pembentukan daerah konservasi kima melalui pelaksanaan tradisi sasi

REVIEW: Symbiosis between the Giant Clams (Bivalvia: Cardiidae) and Zooxanthellae (Dinophyceae)

Giant clams are the largest bivalves in the world that maintain a mutual relationship with zooxanthellae. Individual giant clam can harbor heterogeneous zooxanthellae, at least four taxa in genus Symbiodinium. The Symbiodinium lives in the zooxanthellal tubular system, a tube structure arising from one of the diverticular duct of the clam’s stomach. Since the numbers of zooxanthellae is the one of some significant factors contributing to the clams growth and survival, the giant clams need to adjust the number of zooxanthellae for physiological reason with unclear mechanism. The important role of the symbiotic relationship to the clams can be seen on the survival, growth and nutrition of the clams. There are at least two significant factors determining the symbiosis, i.e. water temperature in related with level of light intensities and ammonium-phosphate rate. Some topic is still unclear, i.e. the determination of species in genus Symbiodinium, the mechanism for adjusting the population numbers of the algae and what kind of environmental factors determining the symbiosis. Thereby further research is still needed to clarify those missing

Gene flow and genetic structure of the seagrass Thalassia hemprichii in the Indo-Australian Archipelago

How genetic variation is distributed across space (genetic structure) and what factors influence the spatial genetic structuring is one of the primary questions in population genetics. The interaction between species biology (e.g. life-history traits) and physical processes operating in the seascape over time, including palaeo-historical events (e.g. sea level fluctuations) and contemporary processes (e.g. ocean currents), have been predicted to influence the extent of gene flow and the spatial genetic structuring in marine organisms. However, the relative contribution of each factor in governing the genetic pattern remains unclear. This study examined the pattern of genetic structure and the factors influencing this using multiple approaches across different temporal and spatial scales in the Indo-Australian Archipelago (IAA), the world’s hotspot of marine biodiversity. By comparing population genetic data of co-distributed marine species (e.g. fishes, molluscs, etc.), this study shows that for marine organisms, the interaction between species biological traits and the physical/environmental processes (habitat variability, water current, etc.) are the greatest drivers of genetic structure in the IAA. Since the physical/environmental processes fluctuate over time, spanning from hours to millennia, the temporal scale (palaeo-historical vs contemporary) at which physical/environmental processes generate genetic structure were examined using seascape genetic analysis. To minimise the effect of different biological traits, the seascape genetic analysis focused only on one species, Thalassia hemprichii, one of the dominant seagrass species in the IAA. The analysis revealed that both palaeo-historical processes (vicariance due to Pleistocene sea level fluctuations) and more contemporary processes (ocean currents) strongly influence the pattern of genetic structure at a regional scale (\u3e300 km). At this spatial scale, the influence of contemporary ocean currents is much smaller than that of historical vicariance. This finding contrasts with previous studies highlighting a strong effect of ocean currents in seagrass connectivity. Only when the effect of historical vicariance was minimised by spatially down-scaling the study from a regional (\u3e300 km) to local (km) scale, contemporary processes, including ocean currents and habitat heterogeneity, were shown to strongly influence the pattern of genetic structure. This study also revealed that significant genetic structure can occur at both regional and local scales. At the regional scale, the genetic clusters span distances of at least 500 km, suggesting that genetic connectivity of T. hemprichii populations occurs over very large geographic scales. At the local scale, significant spatial genetic structure was detected, negating the prediction of a single panmictic population. The strong genetic structuring occurring at both large and small spatial scales suggests that predicting seagrass connectivity solely based on geographic distance is inaccurate, and the relevant distance between populations in the marine system is not purely geographic, but rather determined by other factors operating on the seascape setting such as water currents and habitat heterogeneity. Thus, seascape setting is very important in seagrass gene flow and structure. Based on the pattern of gene flow, genetic structure, and genetic diversity, this research provides recommendations for seagrass conservation management in the IAA, including spatial design of conservation reserves and restoration including transplantation

REVIEW: Ellagitanin; Biosintesis, Isolasi, dan Aktivitas Biologi

Ellagitannin is one of the bioactive groups produced by some of medicinal plants. Ellagitannin is a hydrolysable tannin compound biosynthesized via shikimic acid – gallic acid – pentagalloilglucose pathway. Ellagitannin can be isolated by cascade extraction procedures followed by column chromatography method and preparative HPLC method. The biological activities of ellagitannin are caused by molecular bond between ellagitannin and some other compound, especially protein that makes complex compound and changes physiological processes in cells or tissues of the living- thinks. Biological activities of ellagitannin included anti-diabetic, anti-microbes, anti-viruses, anti-hypertension, anti- oxidative, and anti-cancer or anti-tumor. Key words: ellagitannin, biosynthesis, isolation, extraction, biological activities

Current state of knowledge regarding the effects of dredging-related ‘pressure’ on seagrasses: Report of Theme 5 - Project 5.1.1 prepared for the Dredging Science Node

This review summarises our understanding, from a north west of Western Australia (NWWA) and global perspective, the pressures seagrasses are exposed to from dredging, their tolerance thresholds and responses to dredging related stressors, and the bioindicators of dredging related stressors. From this information, we also identified gaps in our knowledge and areas where environmental management and monitoring approaches could be improved. For this review we used information compiled by the WAMSI Dredging Science Node, which included unpublished data from industry, as well as published reports, articles and books..

Seagrass Connectivity Based on Oceanographic Condition in The Marine Protected Area of Biawak Islands, Indramayu

Seagrasses are an essential component of the coastal environment with provide many ecosystem services beneficial to humans. Understanding the pattern of dispersal of segrasses is important for conservation management. The aimed of this research was to analyze the seed dispersal of the seagrass Enhalus acoroides in the Marine Protected Area of Biawak Islands, Indramayu, based on hydrodynamic modelling. Oceanographic data were downloaded from several open acces website and location of seagrasses based one insitu observation. Then, oceanographic parameters and seed traits were used to develop the particle trajectory model. Our analysis showed that the seafloor’s depth around the islands varied, ranging from 8 m to 48 m. The seed dispersal was strongly influenced by alternating tidal currents (reversing current). The particle trajectory showed that most of the seeds would be transported outward away from each source in the islands, and they settled in deeper areas further from the coast of the islands. This result indicates that the seagrass population in Biawak Islands might depend predominantly on vegetative recruitment, which is slow. This may be related to the low seagrass canopy cover in Biawak Islands

Genetic variability within seagrass of the north west of Western Australia: Report of Theme 5 - Project 5.2 prepared for the Dredging Science Node

The response of seagrass species to on-going pressures such as dredging can be strongly influenced by their ability to adapt to, resist or recover from these pressures. The ability of species to adapt to a pressure, over generations, is influenced by the amount of genetic variation in a population: greater genetic diversity can enhance resistance and higher levels of gene flow between populations can enhance the rate of recovery following complete habitat loss. As seagrass are clonal plants, genetic diversity in a meadow is dependent on both the number of unique clones within the meadow, and distribution of this variation within and among meadows. Understanding the genetic diversity of seagrass meadows can provide important fundamental knowledge for the prediction of dredging impacts, by providing insights into the likelihood of recovery and the processes that may drive that recovery (vegetative regrowth, seed bank recruitment or immigration of recruits). It can also inform management, for example by providing insights into relative vulnerability to pressures, sources of recruitment populations and the importance of maintaining seed banks. However, for most seagrasses and in most parts of the world, extremely little is known about the genetic diversity and connectivity of populations..

Estimasi Stok Karbon Padaekosistem Lamun Di Perairan Utara Papua (Studi Kasus : Pulau Liki, Pulau Befondi Dan Pulau Meossu)

One of the ecological functions of the seagrass ecosystem is the ability to absorb carbon coming from the atmosphere. The ability of seagrass to absorb carbon is carried out through photosynthesis. The absorbed carbon will then be stored in the form of seagrass biomass in the seagrass body. This study aims to estimate the carbon stock content stored in seagrass ecosystems in the Northern waters of Papua including on Liki Island, Befondi Island, and Meossu Island. The calculation of carbon stock is done by converting seagrass biomass using constants derived from representative values of seagrass carbon content in Indonesian waters. In general, based on the results obtained indicate that the biomass at the bellow ground of the seagrass is greater than the biomass at above ground the seagrass. The value of organic carbon content in seagrasses is influenced by seagrass biomass. The carbon stock content in the seagrass ecosystem in the study area is in the range of 18,04 – 419,46 g C / m2. Stations on Liki Island have generally higher carbon stocks compared to stations on other islands.Salah satu fungsi ekologi dari ekosistem lamun yaitu memiliki kemampuan dalam menyerap karbon yang berasal dari atmosfer. Kemampuan lamun dalam menyerap karbon dilakukan melalui proses fotosintesis. Karbon yang terserap selanjutnya akan disimpan dalam bentuk biomassa lamun  pada tubuh lamun. Penelitian ini bertujuan untuk mengestimasi kandungan stok karbon yang tersimpan pada ekosistem lamun di Perairan Utara Papua tepatnya di Pulau Liki, Pulau Befondi dan Pulau Meossu. Perhitungan stok karbon dilakukan dengan melakukan konversi biomassa lamun menggunakan konstanta yang berasal dari nilai representatif konsentrasi kandungan karbon pada lamun yang berada di Perairan Indonesia. Secara umum berdasarkan hasil yang diperoleh menunjukkan bahwa biomassa pada bagian bawah lamun lebih besar dibandingkan dengan biomassa pada bagian atas lamun. Nilai kandungan karbon organik pada lamun dipengaruhi oleh biomassa lamun. Kandungan stok karbon pada ekosistem lamun di wilayah penelitian  berada pada kisaran 18,04 – 419,46 gC/m2. Stasiun yang berada di Pulau Liki memiliki stok karbon yang umumnya lebih tinggi dibandingkan dengan stasiun yang berada di pulau lainnya.

Ocean connectivity and habitat characteristics predict population genetic structure of seagrass in an extreme tropical setting

Understanding patterns of gene flow and processes driving genetic differentiation is important for a broad range of conservation practices. In marine organisms, genetic differentiation among populations is influenced by a range of spatial, oceanographic, and environmental factors that are attributed to the seascape. The relative influences of these factors may vary in different locations and can be measured using seascape genetic approaches. Here, we applied a seascape genetic approach to populations of the seagrass, Thalassia hemprichii, at a fine spatial scale (~80 km) in the Kimberley coast, western Australia, a complex seascape with strong, multidirectional currents greatly influenced by extreme tidal ranges (up to 11 m, the world\u27s largest tropical tides). We incorporated genetic data from a panel of 16 microsatellite markers, overwater distance, oceanographic data derived from predicted passive dispersal on a 2 km-resolution hydrodynamic model, and habitat characteristics from each meadow sampled. We detected significant spatial genetic structure and asymmetric gene flow, in which meadows 12–14 km apart were less connected than ones 30–50 km apart. This pattern was explained by oceanographic connectivity and differences in habitat characteristics, suggesting a combined scenario of dispersal limitation and facilitation by ocean current with local adaptation. Our findings add to the growing evidence for the key role of seascape attributes in driving spatial patterns of gene flow. Despite the potential for long-distance dispersal, there was significant genetic structuring over small spatial scales implicating dispersal and recruitment bottlenecks and highlighting the importance of implementing local-scale conservation and management measures