Application of Artificial Neural Networks for Mangrove Mapping Using Multi-Temporal and Multi-Source Remote Sensing Imagery

Mangroves, as unique coastal wetlands with numerous benefits, are endangered mainly due to the coupled effects of anthropogenic activities and climate change. Therefore, acquiring reliable and up-to-date information about these ecosystems is vital for their conservation and sustainable blue carbon development. In this regard, the joint use of remote sensing data and machine learning algorithms can assist in producing accurate mangrove ecosystem maps. This study investigated the potential of artificial neural networks (ANNs) with different topologies and specifications for mangrove classification in Iran. To this end, multi-temporal synthetic aperture radar (SAR) and multi-spectral remote sensing data from Sentinel-1 and Sentinel-2 were processed in the Google Earth Engine (GEE) cloud computing platform. Afterward, the ANN topologies and specifications considering the number of layers and neurons, learning algorithm, type of activation function, and learning rate were examined for mangrove ecosystem mapping. The results indicated that an ANN model with four hidden layers, 36 neurons in each layer, adaptive moment estimation (Adam) learning algorithm, rectified linear unit (Relu) activation function, and the learning rate of 0.001 produced the most accurate mangrove ecosystem map (F-score = 0.97). Further analysis revealed that although ANN models were subjected to accuracy decline when a limited number of training samples were used, they still resulted in satisfactory results. Additionally, it was observed that ANN models had a high resistance when training samples included wrong labels, and only the ANN model with the Adam learning algorithm produced an accurate mangrove ecosystem map when no data standardization was performed. Moreover, further investigations showed the higher potential of multi-temporal and multi-source remote sensing data compared to single-source and mono-temporal (e.g., single season) for accurate mangrove ecosystem mapping. Overall, the high potential of the proposed method, along with utilizing open-access satellite images and big-geo data processing platforms (i.e., GEE, Google Colab, and scikit-learn), made the proposed approach efficient and applicable over other study areas for all interested users.

Cellulase enzyme activity of the bacteria isolated from mangrove ecosystem in Aceh Besar and Banda Aceh

Cellulolytic bacteria is one of the beneficial bacteria that can found in mangrove ecosystem. The purposes of study were to analyse the cellulolytic index, and to analyse the cellulase activity of bacteria isolated from soil mangrove. Qualitatively, assessment of cellulase activity were carried out at the Microbiology laboratory of Fish Quarantine Station, Quality Control and Safety of Fishery Products (SKIPM) Aceh, while quantitatively was observed in microbiology laboratory, Biology Department, IPB. Assessment of qualitative cellulase activity is performed by growing the selected pure isolate on 1% CMC medium then spilled 1% congo red to test its cellulolytic potential. Cellulolytic potential was determined by clear zone performed around the colony after congo red flooded. The quantitative cellulase enzyme activity test carried out by DNS method tested on one selective isolate. There were 21 from 39 isolates showed a clear zone isolated from mangrove soil. The cellulolytic index (CI) obtained ranged from 0.07 to 0.80 classified as low cellulolytic index criteria. The cellulolytic index was higher in bacteria isolated from mangrove rehabilitated than mangrove unrehabilitated. The highest cellulase activity and specific cellulase activity of BTMD32 was at 48 hours with the value were 0.0012 U/ml, 0.077 U/mg, respectively. The result concluded that the bacteria cellulolytic isolated from mangrove soil had low cellulolytic index, low cellulase activity, and low specific cellulase activity.

Impacts of Livelihood Activities on the Environment and Natural Resources of Can Gio Mangrove Forest, Ho Chi Minh City

In recent years, local livelihood activities in the Can Gio district have increased significantly, including aquaculture practices, aquaculture cultivation, salt-works, forest guard, farming, livestock, tourism, and etc. These livelihood activities have contributed remarkably to the local economy and the improvement of living conditions for local people. However, the burgeoning development of these activities have posed negative impacts on the mangrove ecosystem in Can Gio. In which, the use and exploitation of existing human and natural resources are paid inadequate attention. The purpose of this study is to identify livelihoods by conducting a survey with 536 questionnaire samples in both the buffer and transition zones in Can Gio Mangrove Forest. In addition, the quality of surface water sources was examined by collecting 70 surface water and wastewater samples. The results show that the quality of surface water meets the allowable limits of QCVN 08-MT:2015/BTNMT. The extent of the impact from livelihood activities on the environment of mangrove forest is at the medium level. However, the livelihood of aquaculture cultivation practices has the most affect on the environment and natural resources and is posing negative impacts on the quality of water sources in Can Gio Mangrove Forest. Therefore, these findings will be useful information for decision makers of the local authority in building an appropriate planning for aquaculture cultivation area. Further, irrigation and drainage systems for aquaculture practices need to be invested to control and handle wastes from aquaculture cultivation areas.

Systematics of Modern Benthic Foraminiferal Assemblages From the Deltaic Mangrove Ecosystem of Sundarbans

The contemporary intertidal foraminifera and estuarine environment information were collected from the four sites adjoining the deltaic mangrove environment in the Sundarbans. The marsh zones of the south-western coastal region of Bangladesh were examined for modern benthic foraminifera and to expound on the relationship of the foraminiferal assemblages with the environment. Due to high inaccessibility and remoteness, the taxonomic study of foraminifera and its depositional environment remains largely overlooked in the Sundarbans of Bangladesh. This study includes a detailed survey of depositional environment of these fluvio-deltaic to shallow marine sediments. The seventeen species belonging to fourteen genera representing nine families were recorded from surficial sediment of supratidal, intertidal, and dune environment of Kotka, Jamtala, Kochikhali, and Dimer char area. In the present study, these foraminiferal assemblages are characterized calcareous and agglutinated foraminifera. The Kotka beach is recognized as Nonionina assemblage zone, Jamtala beach designated as Ammonia assemblage zone, Kochikhali as Nonionina assemblage zone and Dimer char as Rosalina-Nonionina-Nonionella assemblage zone. The deposition of foraminifera is restricted to Sundarbans’ low to high marsh zone. J. Asiat. Soc. Bangladesh, Sci. 47(2): 121-136, December 2021

Mangrove crab intestine and habitat sediment microbiomes cooperatively work on carbon and nitrogen cycling

Mangrove ecosystems, where litter and organic components are degraded and converted into detrital materials, support rich coastal fisheries resources. Sesarmid (Grapsidae) crabs, which feed on mangrove litter, play a crucial role in material flow in carbon-rich and nitrogen-limited mangrove ecosystems; however, the process of assimilation and conversion into detritus has not been well studied. In this study, we performed microbiome analyses of intestinal bacteria from three species of mangrove crab and five sediment positions in the mud lobster mounds, including the crab burrow wall, to study the interactive roles of crabs and sediment in metabolism. Metagenome analysis revealed species-dependent intestinal profiles, especially in Neosarmatium smithi, while the sediment microbiome was similar in all positions, albeit with some regional dependency. The microbiome profiles of crab intestines and sediments were significantly different in the MDS analysis based on OTU similarity; however, 579 OTUs (about 70% of reads in the crab intestinal microbiome) were identical between the intestinal and sediment bacteria. In the phenotype prediction, cellulose degradation was observed in the crab intestine. Cellulase activity was detected in both crab intestine and sediment. This could be mainly ascribed to Demequinaceae, which was predominantly found in the crab intestines and burrow walls. Nitrogen fixation was also enriched in both the crab intestines and sediments, and was supported by the nitrogenase assay. Similar to earlier reports, sulfur-related families were highly enriched in the sediment, presumably degrading organic compounds as terminal electron acceptors under anaerobic conditions. These results suggest that mangrove crabs and habitat sediment both contribute to carbon and nitrogen cycling in the mangrove ecosystem via these two key reactions.

Mangrove Ecosystem Biodiversity in Malacca Strait and Its Economic Values to Local Community: A Case Study in Riau Coastline

The mangrove ecosystem holds a lot of potentials to be utilized by local communities in the Riau Coastline. Therefore, this study was carried out to assess the biodiversity of flora and fauna in the Riau Coastline mangrove ecosystem and its impacts on local communities. The transect was performed to identify soil conditions, distribution, and the dominance of flora species, while field observations and interviews with residents were conducted to determine the presence of fauna and discover the ecosystem’s benefit to the local community's economy. Based on the results, Rhizophora mucronata and Rhizophora apiculata has the highest relative dominance (RDC) and important value index in all observed stations. On the other hand, the fish/water biota species has the highest diversity and have economic that mostly serve as a catch for local fishermen. Ecotourism is also encouraged to boost the community's economy and aid ecological learning for sustainability purposes. The mangrove ecosystem's existence remains sustainable because fisheries are the main commodity, however, logging is less desirable as a source of income.

Perluasan Hutan Mangrove dalam Mitigasi Risiko Bencana Pemanasan Global: Kegiatan PkM di Kawasan Pesisir Muara Angke Jakarta

One of the disasters caused by humans is global warming. Global warming is a big problem that is being faced by all human beings and living things on earth. One of the activities that can be carried out in mitigating the risk of global warming is through Mangrove Ecosystem Rehabilitation. The existence of the Mangrove ecosystem in the coastal area of ​​DKI Jakarta Province is currently experiencing a decline in line with the development that changes the function of the area from a protected function to a cultivation function. One area that has experienced this is the coastal area in Muara Angke which has had a negative impact on the environment, namely the function of protecting and securing the coast will naturally be lost. In this 2021 Community Service program, STMA Trisakti has participated in helping to solve the problem of the rate of degradation of the Mangrove Forest by planting 1000 mangrove seedlings in the Muara Angke Eco-tourism area. The planting was carried out on World Environment Day on 5 June 2021.