No abstract

Research on the structure of seagrass communities in the waters of the island Mantehage was conducted in September 2010. The purpose of this study is to collect data and information on the structure of seagrass communities. Observations includes the identification seagrass species, measuring the number of individual/stand, cover percentage of each type/species on the transect. 6 types of seagrass found, i.e. Enhalus acoroides, Halophila ovalis, Thalassia hemprichii, Thalassodendron ciliatum, Cymodocea rotundata and Syringodium isoetifolium. Seagrass species composition and distribution varies at each location and is dominated by the presence of Thalassia hemprichii (48.14%) with coverage percentage ranges between 15.91% to 35.11%. Diversity index values ranged from 0.79 to 1.69 ; evenness index between 0.57 to 0.94 and the index of dominance between 0.20 to 0.56. In conclusion, the condition of seagrass meadows in Mantehage island is relatively good and can support marine life adequately.Keywords : Structure communities, seagrass, Mantehage Island

Penelitian ini telah dilaksanakan pada dua musim yaitu musim barat dan musim peralihan-I untuk mengetahui kualitas air laut dan indeks pencemaran di Teluk Manado. Pengukuran suhu, salinitas, kecerahan, pH dan oksigen terlarut dilakukan secara in situ (langsung di lapangan) sedangkan kekeruhan, fosfat dan nitrat dianalisa di labaratorium WLN-Manado. Semua metode analisis berdasarkan pada buku Standards Methods for The Examination of Water and Wastewater (APHA, AWWA, WEF, 2005). Hasil perhitungan indeks pencemaran menunjukkan Teluk Manado masih dalam kondisi baik hingga tercemar ringan. Variasi nilai suhu, salinitas, kecerahan dan kekeruhan air laut masih dalam kondisi relatif normal untuk kategori perairan pantai. Derajat keasaman (pH), oksigen terlarut (DO), fosfat dan nitrat masih dalam batas aman kesuburan suatu perairan dan masih baik untuk kehidupan dan perkembangan biota laut.

Seagrasses offer diverse ecosystem services, yet, they are among the most threatened ecosystems. When degraded or destroyed, their services are lost or reduced in the process, affecting, for instance, local communities directly dependent on their livelihood provision. The Intergovernmental Panel on Climate Change (IPCC) reported that climate change is projected to worsen over time; thus, there is an urgent need for mitigation strategies in practice and also in the longer term. This work aims to provide an alternative perspective of seagrass restoration as a nature based solution (NbS) on a global scale, yet, giving an emphasis on tropical regions such as Indonesia. We focused on seagrass restorations which are not yet well established in comparison with other restoration programs (e.g., mangroves) despite their critical roles. We present in this work how restoring seagrass meadows fits the global standard of NbS published by the International Union for Conservation of Nature (IUCN). The results of this study can serve as a basis for promoting seagrass restorations as NbS against climate change particularly in countries with a wide extent of seagrass coverage.

A study aiming to compare the abundance and species composition of invertebrates among four sites (Strickland East, Strickland West, Strickland Far East and North Point) on intertidal rocky platforms around Rottnest Island, Western Australia was conducted in January 2018. Eight quadrats with 1m by 1m dimension were haphazardly placed at each of three zones in the sampling site including the inner, middle and outer zone in relation to the shoreline in order to obtain the data of invertebrate community structure. The result of a one-way ANOVA test with a robust covariance matrix showed that the intertidal invertebrate abundance among the four sampling sites was statistically significant different (P<0.05). Then, a further test using Tukey post hoc analysis found that invertebrate abundance at Strickland East was significantly different with the assemblage of invertebrate at North Point, Strickland West and Strickland Far East at the level of significance of 1%, 5% and 10%, respectively. Whereas the cluster analysis revealed that there were two clusters of invertebrate species at Rottnest Island. In the future, it is recommended to conduct an invertebrate community structure monitoring program consistently every year covering all intertidal sites around Rottnest Island in order to obtain reliable data useful for conservation and management purposes.

Seagrass canopies are important components of the world’s coastal environments providing critical ecological services. Nearshore hydrodynamics, i.e., waves and currents, are essential in controlling the ecological processes across coastal environments. Seagrass meadows can impose more complex hydrodynamics processes by attenuating sea-swell waves and decreasing the impact of nearshore mean water level rise due to wave setup and Infragravity (IG) waves. Consequently, the seagrasses dissipate waves and reduce flows allowing sediments to settle and accrete the shorelines. However, despite their significant roles, knowledge of hydrodynamics in the Indonesian seagrass ecosystems is relatively limited compared to other coastal ecosystems such as sandy beaches, mangroves, and coral reefs. This review highlights the dynamics of waves and currents, and their interaction with sediment transport and ecological processes, including biogeochemical and dispersal processes on the seagrass ecosystem contributing to the existing seagrass research in Indonesia. The associated literature is collected from scientific databases such as Scopus and Google Scholar that range between 1965 and 2021. The result showed that most of the research on hydrodynamic in seagrass ecosystems was carried out in temperate zones. Until recently, there have been limited publications discussing the interaction between the Indonesian (tropical) seagrass ecosystem and hydrodynamics parameters, even though the region has abundant seagrass species. Moreover, Indonesia is strongly influenced by various atmospheric-oceanic forcing, including the Asian monsoon affecting the dynamic of the coastal area with seagrass ecosystems. At a canopy scale, the correlation between the nearshore (tropical) hydrodynamics and ecological processes in the system is yet to be explored. Considering the potential benefit of seagrasses to coastal ecosystems, developing future research in hydrodynamics across the ecosystem is critical to overcoming the knowledge gaps in Indonesia. The knowledge gained could support the Indonesian seagrass ecosystem services and their resilience to potential hazards and climate change.

The unprecedented rate of climate change and over-exploitation of resources has had a significant impact on ecosystems around the globe. In particular, the oceanic realm has encountered multiple changes to ecosystem conditions, food web dynamics and habitat constructs. Many marine species have been driven to shift their geographical range in reaction to reaching their physiological limits causing severe metabolic stress. This includes key fishery targets, such as pelagic and carnivorous fish, that supply many nations with their primary or secondary protein source. The shift also spurs an array of political and economic consequences due to the need for fisheries to follow or target different fish stocks that are no longer in their exclusive economic zone or legal fishing waters. For this reason, and many other logistical and financial reasons, management strategies have struggled to maintain and sustain fish stocks around the globe. This paper will look at a Northeast Atlantic mackerel case study, compare and analyse the implications of shifting fish stocks, and illustrate difficulties related to managing the fisheries which target these stocks. Furthermore, we highlight the need for a combination of global strategies, and smaller-scale ecosystem approaches in fisheries management to be able to sufficiently sustain fisheries and thus future food security, during a time of climatic change.

Large seagrass meadows in Indonesia are predicted to have a significant ability in capturing and storing carbon and are useful to mitigate global climate change. However, most of the available data are derived from short-term carbon storage of living biomass, whereas data on long-term carbon storage in the soil is still limited. This study, therefore, aims to measure soil carbon storage in mono-specific Enhalus acoroides meadows in Pari Island. A total of nine soil cores was collected in a 100×100 m2 area. The parameters were soil depth, dry bulk density (DBD), and Corg content. We applied a PVC corer with 7.4 cm in diameter and 80 cm in length to collect the soil. The length of the soil core varied between 8 and 67 cm. The mean (±SE) of soil dry bulk density is 0.98±0.04 gr/cm3 and the median is 1.1 gr/cm3, while Corg content is 2.1±0.1% soil DW (mean±SE) and 1.9% (median). E. acoroides vegetation in Pari Island stores around 63 Mg Corg/ha organic carbon in 8-67cm or 34cm (mean depth) of topsoil. Carbon storage of these mono-specific meadows is comparable to soil carbon storage in the seagrass ecosystems per hectare areas on national, regional, and global levels.