Lake Limboto Research Articles

Analysis of Microfaces and Depositional Environment of Limestone in North Isimu Area, Gorontaolo Regency

The geological conditions in the northern part of Lake Limboto vary greatly from the constituent rocks to the working geological structures. Lithological variations consist of volcanic and plutonic rocks to limestone. The area where limestone is widely distributed is in the North Isimu Region, Gorontalo Regency. This research aims to analyze the geological conditions, microfacies and depositional environment of limestone in the North Isimu Region, Gorontalo Regency. The research methods used to achieve this goal consist of field surveys and petrographic laboratory analysis. Field surveys include taking rock samples, taking coordinate points, taking elevation, geomorphological observations, observing geological structures and taking field documentation. Meanwhile, petrographic analysis of rocks uses a polarizing microscope as a tool to follow up megascopic observations. Observation of rock incisions under a microscope using cross nicol and parallel nicol. Based on the results and discussion, it shows that the geomorphology of the research area includes structural hills with sub-parallel river flow patterns. The geological structure of the research area is a descending fault trending northwest-southeast. The research area is divided into four facies, namely foraminifera wackestone, crystalline limestone, foraminifera algae packstone and coralline floatstone. Standard microfacies (SMF) in the North Isimu Region consists of three SMF namely SMF-3, SMF-4 and SMF-5 with two limestone depositional environmental zones namely toe of slope (FZ-3) and slope (FZ-4). FZ-3 was deposited at the end of the foreslope zone and FZ-4 was deposited seaward of the foreslope from the edge of the carbonate debris platform.Keywords: Limestone; Microfacies; Depositional Environment; North Isimu

Prevalensi, Intensitas, dan Dominansi Parasit pada Ikan Manggabai (Glossogobius giuris) di Danau Limboto Provinsi Gorontalo

This study aimed to identify the different types of parasites infecting manggabai fish (Glossogobius giurus) in Lake Limboto, in addition to analyzing the intensity, prevalence, and dominance of parasites in the population. Twenty manggabai fish samples were collected from three different locations in Lake Limboto, namely Dembe 1, Tabmela, and Hutuo. The parasite examination process was carried out at the Zoology Laboratory of the Biology Department of Gorontalo State University, focusing on organs such as skin, gills, fins, and digestive organs. The method applied was the native method, which involves direct observation. The identification results showed the presence of three types of parasites in manggabai fish, namely Gyrodactylus sp., Camallanus sp., and Ligula intestinalis. The highest prevalence was recorded for Gyrodactylus sp. at 65%, indicating a significant spread of parasites in the fish population. The parasite intensity of Camallanus sp. from Hutuo at 7. The parasite Ligula intestinalis showed the highest dominance with a value of 44%. Meanwhile, the highest prevalence and intensity values were placed in the frequent and mild categories.

Morphometric characteristics of Lake Limboto as critical lake in Gorontalo Province, Indonesia

This research aims to investigate the factors leading to siltation in Lake Limboto by analyzing its morphometric characteristics gathered through direct field measurements and remote sensing using Geographic Information System (GIS). Lake Limboto covers an approximate surface area of 26.09 square kilometers, boasts a maximum depth of 4 meters, and maintains an average depth of 2.83 meters. The Shoreline Development Index (SDI) stands at approximately 2.57, indicating an irregular shape of the lake's water body, while the Lake Volume Development (VD) index, at 2.12, suggests a generally flat lake bottom. The Relative Depth (Zr) registers at around 0.69%, as observed from the water turbidity level. The lakebed relief in the vicinity of the lake's periphery is predominantly flat and shallow, particularly in the western, northern, and southern regions, with depths measuring less than 2 meters. In contrast, the lakebed relief in the central and eastern sections tends to be less flat but still features depths of less than 4 meters. Siltation in Lake Limboto primarily results from high sediment input originating from erosion processes, agricultural activities, and settlements in the surrounding area.

Analysis Of Mercury (Hg) In Mujair Fish (Oreochromis mosambicus) In Limboto Lake, Gorontalo Province

The occurrence of silting of the lake and sedimentation in Limboto Lake has become a place for the deposition of heavy metals, especially mercury. In recent years it has been known that the water of Lake Limboto has been polluted by mercury based on data from the Agency for the Environment, Research and Technology (Balihristi), Gorontalo Province in 2007.This study aims to analyze the mercury (Hg) content of mujair fish (Oreochromis mossambicus) in Limboto Lake. This research was conducted in November 2018- June 2019. The method used in this research is descriptive method. Sampling of water and fish was carried out by purposive sampling by dividing the research location into 2 stations, namely Station I in the floating net cages and Station II outside the KJA Measurement of mercury content (Hg) was carried out at the Laboratory of Fisheries Product Quality Development and Testing (LPPMHP) Gorontalo City using the Atomic Absorbtin Spectrophotometer (AAS). From the results of the study, it was found that, the Mercury (Hg) Content in Lake Limboto Waters, Stasion I was 0.0014 ppm and Station II was 0.0007 ppm, and for mujair fish organs the highest was in meat, namely outside KJA 0.0037 ppm and in meat, the lowest was in KJA 0.0035 ppm.. Nakoe et al. (2014) examined the risk of exposure to mercury (Hg) in humans who consume Mujair (Oreochromis niloticus) from Lake Limboto using the Limboto approach. Limboto using an environmental health analysis approach with a variable test method of body weight, consumption level and frequency. Concentration mercury levels of tilapia in Lake Limboto are between 0.007 - 0.089 mg/kg while the mercury levels in the lake are between 0.0014 mg/L. lake is around 0.0014 mg/L.

Diversity of actinomycetes on plant rhizosphere of karst ecosystem of Gorontalo, Indonesia

Abstract. Retnowati Y, Kandowangko NY, Katili AS, Pembengo W. 2024. Diversity of actinomycetes on plant rhizosphere of karst ecosystem of Gorontalo, Indonesia. Biodiversitas 25: 907-915. The objective of this study was to isolate and identify the actinomycetes associated with the rhizosphere of plants in the karst ecosystem. This study was descriptive-quantitative. Soil sampling was conducted at three locations of the karst ecosystem of Gorontalo, i.e., Bangga Hills at Bangga Bubaa Coastal area of Gorontalo District, Hills around Lake Limboto of Gorontalo District, and Oluhuta Beach Hills at Bone Bolango District. Rhizosphere-soil sample was collected from 15-30 cm of soil depth. Isolation of actinomycetes was performed using the plate method. The screening of phosphate-solubilizing bacteria was based on the ability to solubilize phosphates indicated by the clear zone on the Pikovskaya medium. Identification of actinomycetes bacteria based on morphology and molecular characters. The morphology character included the color of aerial and substrate mycelium. Molecular characteristics based on the sequence of 16S rRNA gene compared to sequence data on the gene bank of NCBI. The phylogenetic tree reconstruction was based on the Neighbor-joining algorithm. The results successfully found six isolates, including three actinomycetes isolates, two non-actinomycetes bacteria, and one yeast. They were isolated from the rhizosphere of Malastoma malabathrum, Chromolaena odorata, Cycas rumphii, Leucaena leucocephala, and Jatropha curcas. The actinomycetes isolate showed plant-growth-promoting potential indicated by solubilizing phosphate and Indole 3-Acetic Acid production activities. Based on the molecular analysis, actinomycetes were closely related to Streptomyces aegyptia (MT505707.1:42-1426), Streptomyces sp. GGCR-6 (MH718844.1:5-1391), and Streptomyces carpaticus strain PES-A23 (MH712039).

Cultural Fluctuation of Lake Communities by the Shrinkage of Lake Limboto, Indonesia

The fluctuating conditions of Lake Limboto have greatly affected the activities of people living around the lake. The shallowing and narrowing of the lake poses a significant problem to local people’s survival. The lake is predicted to disappear by 2030, which will consequentially lead to a diminishment in the productivity of the lake. This article aims to analyze how the communities around the lake respond in their daily activities to the transformation of the lake and the shocking prediction about its lifespan. This study uses an interdisciplinary approach by integrating multiple fields of study to understand and address the problems regarding this issue. This research comprised a literature review, field survey, and in-depth interview process around the lake. This research relied on the framework of cultural studies to analyze the survival and resilience of the people around the lake, gaining an understanding of their special daily activities. The results of this study show that some people are aware of the lake’s gradual recession, but they have not prepared for it, treating the problem as only a government affair. They continue to live at the lake’s shores, enduring even amidst impoverished conditions.

Socioeconomic status, lake knowledge, and community participation in the sustainable Lake Limboto management, Gorontalo Regency

Lake Limboto, situated in Gorontalo, Indonesia, confronts severe threats jeopardizing its sustainability. Widespread deforestation in the watershed area has led to excessive sedimentation within the lake, consequently diminishing its water storage capacity and compromising its flood control function. This degradation has manifested itself in downstream droughts during the dry season and flooding during the rainy season. Historical data reveals a stark reduction in Lake Limboto’s size, plummeting from approximately 3,644.5 ha in 1991 to around 2,693.9 ha in 2017. This study aims to provide comprehensive examination of the interplay between the socioeconomic status of the local community and their understanding of the lake ecosystem. Furthermore, it delves into how these factors produce synergies that shape and impact community involvement in sustainable lake management initiatives. Hypothesis testing yielded significant results, affirming the existence of a positive correlation between socioeconomic status, knowledge of the lake ecosystem, and active community participation in sustainable lake management efforts. The findings underscore the critical importance of socioeconomic factors that need to be considered when designing strategies for the preservation and sustainable management of Lake Limboto. Integrating the community into conservation initiatives is necessary, given their intrinsic relationship with the lake. By acknowledging and leveraging the nexus between socioeconomic status, ecological knowledge, and active participation, stakeholders can formulate more effective and inclusive strategies for safeguarding Lake Limboto’s ecological integrity. This study contributes valuable insights for policymakers, environmentalists, and local communities alike, emphasizing the necessity of collaborative efforts to ensure the long-term resilience and vitality of Lake Limboto.

Relation of morphometric characteristics to land degradation in the Biyonga sub-watershed, Gorontalo Regency, Indonesia

One of the crucial watersheds causing significant sedimentation in Lake Limboto is the Biyonga sub-watershed. This study aimed to examine and evaluate the morphometric characteristics of the watershed that contribute to possible erosion and land degradation hazards in the Biyonga sub-watershed. ALOS PALSAR (11.25 m), TERRASAR-X (5-10 m), and DEMNAS satellite images with a resolution of 8 m were employed, combining spatial analysis with a remote sensing approach and a Geographic Information System. Basic data of morphometric parameters were generated through basin morphometric analysis using Digital Elevation Model (DEM) image extraction. Then, the linear aspect, area, and relief parameters were defined by mathematical morphometric equations. The calculation results were interpreted into field data to confirm the relationship between watershed morphometric characteristics related to erosion and land degradation events. The results of the morphometric analysis showed that the flow density is a medium-textured criterion with a long elongation shape and an elongated flow pattern. Based on the relief aspect, the Biyonga Sub-watershed is in the form of moderate relief, has various characteristics with an average ratio, and has terrain that can trigger erosion and land degradation. This study has provided information that degraded land is not fully influenced by morphometric factors but due to poor land use and management systems, which accelerate erosion and sedimentation.

Limboto Lake Management Model Based on Adaptive Governance

This research aims to analyze motivation and issues, structure and networks between stakeholders in the management of Lake Limboto; and explains how the adaptive model intervenes in the management of Lake Limboto in Gorontalo Regency. This research uses a qualitative approach. Data collection techniques include in-depth interviews, documentation, observation and carrying out Focus Group Discussions (FGD). Data were analyzed using the spiral technique. The results of the research show that the Gorontalo Regency Government from an Adaptive Governance perspective is not yet able/not ready to survive in the face of environmental changes that may occur at any time. The motivation and issues of each stakeholder show a desire to manage and even save Lake Limboto from damage, however, activities are still found in the Lake carried out by the community which actually accelerate the degradation of the Lake environment. The structural pattern in the management of Lake Limboto requires an adaptive model that utilizes the potential resources of each stakeholder, both from the civil sector; Private and Government.

Diagenesis Analysis of Padengo Limestone Area, Gorontalo Regency Based on Petrographic Method

Carbonate rocks are rocks composed of carbonate minerals that are chemically formed in the form of solutions, and there are organisms involved in their formation. The limestone found around Lake Limboto is very interesting, because the water in the lake is freshwater while the limestone is characteristic of a marine environment. Diagenesis is a natural process in sedimentary rocks that occurs from the initial deposition until it reaches the limit of metamorphism will be formed. The research area is located in Padengo Village, West Limboto Subdistrict, Gorontalo Regency with a research area of 7.72 Km2. This research aims to analyze the diagenesis of limestone in the Padengo area of Gorontalo Regency using the petrographic method. The methods used are field geological survey and petrographic analysis. The results showed that the geology of the Padengo area is composed of a wackestone limestone facies unit, a crystalline limestone facies unit, and an alluvial sediment unit. The diagenesis type of the study area consists of neomorphism, micritization, dissolution, cementation, and dolomitization. From the type of diagenesis, it can be determined that the limestone diagenesis environment of the study area starts from the marine phreatic zone, then the burial zone, and ends at the meteoric vadose zone.

Biodiversity of Migrant Birds in the Limboto Lake Region, Gorontalo Province

The bird population in Indonesia is rich in diversity, this is based on the number of bird populations and environmental conditions that are still maintained so as to allow the birds to live. This study aims to describe the types of migratory birds in Lake Limboto. The method used in this study is the count point method and with 4 observation points for 7 days on different days. The starting point of the observations is carried out alternately for each station so that there are variations in the observation time at each station. Overall, the classification of migratory birds in the Limboto Lake area is classified as moderate with an index carbon index value of 1.79. Migratory birds found in the Lake Limboto area are 9 species of migratory birds belonging to 7 families with a total of 706 individuals. The highest index value H'= 1.63 is at station 1, the diversity index value is moderate and the lowest hidden index H'= 0 is at station 4, the index value is relatively low.

Strategies on Degraded Lake Management for Sustainable Environmental Ecosystem in Lake Limboto, Gorontalo

This study aims to formulate an integrated and sustainable management strategy for Lake Limboto’s sustainable ecosystem. The stages of the study include (1) identifying the problems that occur in Lake Limboto and analyzing the general conditions of the ecosystem, which includes biophysical waters, land use patterns in water catchment areas, and socio-economics; (2) measuring the sustainability of the lake management using the Multi-Dimensional Scaling (MDS) method and leverage analysis. The results of the Multi-Dimensional Scaling analysis show that the sustainability index value of the ecosystem, economic, social, institutional, and technological dimensions are less sustainable, less than 50. In contrast, the economic dimension is entirely sustainable at 62.90; meanwhile, the ecosystem dimension index is 18.59, which means the sustainability status is poor. These figures indicate that the management of Lake Limboto and its surrounding area mainly considers the economic aspects and relatively ignores the dimensions of its ecosystem.

Pemanfaatan Sedimen Aquatis Sebagai Filler dalam Campuran Aspal Beton Lapis Aus

The sedimentation of Lake Limboto causes silting so that dredging is needed to be used later in road construction. This study aims to test the waste of Lake Limboto can be used as a filler in the AC-WC mixture. For the percentage of filler content in the mixture and analyze the value of Marshall characteristics using Limboto Lake sediments. Aggregate originating from AMP PT. Cahaya Nusa Sulutarindo is located in the Isimu sub-district, Gorontalo Regency. The test was carried out at the Engineering LAB, Gorontalo State Civil University. The test method is the Marshall Test which refers to the general specifications of the 2018 Revision II Road and Bridge Highways. Marshall AC-WC mixture uses an optimum asphalt content of 6.35%: sediment variation 0.1% and 0.2% all values of Marshall characteristics meet the requirements according to the general specifications for 2018 revised road and bridge construction work. Variation of 0.1% is obtained the value density 2.304; VIM 3.66; VMAs 17.91; VFA 79.56; free 1259.44; stream 3.18; a variation of 0.2% obtained a density value of 2,314; VIM 3.21; VMA 17.52; VFA 81.68; fortress 1208.08; flow 3.00. The ideal mixture material for the AC-WC mixture using Lake Limboto sediment with an optimum asphalt content of 6.35% obtained 14.0% coarse aggregate (CA) of 157.3 gr, medium aggregate (MA) 34.0% of 382.1 gr and 52.0% fine aggregate (FA) of 584.4 g without sediment, for variations of 0.1% sediment of 0.6 g and 0.2% of 1.2 g.

Performances of Erosion Control Blanket Made From Palm Fiber On Reducing Erosion In The Slopes Of Lake Limboto Basin

Lake Limboto is one of the key lakes with severe siltation, caused by sediment delivered by river currents. This study aims to reduce the impact of sedimentation by controlling erosion with a palm fiber net with mesh dimensions of 5 cm x 5 cm and a thickness of 5 mm. The Palm fibre installation is installed on slopes with erosion potential; each location has a different slope: location 1 has a slope of 40o, location 2 has a slope of 45°, and location 3 has a slope of 50°. With the findings obtained, palm fiber nets erosion control was shown to be effective in repelling erosion. The first site has an 8:3 ratio, the second location has a 5:2 ratio, and the third place has a 1:0.5 ratio, net performance at each location of 42% location 1, 39% location 2, 41% location 3 and 0% at location 4. Differences in soil structure and slope of the slope generate variations in the data acquired from each location.

Detection of Changes in Water Surface Area in Limboto Lake Using Landsat Data From 1990 to 2020

Lake Limboto is included in the fifteen priority lakes due to its increasingly critical condition. Long-term observations of changes in the lake water surface area are carried out to understand the impact of changes better and protect the ecosystem of water resources. The use of remote sensing technology products in Landsat 4 TM, Landsat 5 TM, Landsat 7 ETM +, and Landsat 8 OLI satellite images and Google Earth Engine is a suitable combination to study the dynamics of Lake Limboto. The water index used are NDWI (Normalized Difference Water Index), MNDWI (Modified Normalized Difference Water Index), and AWEI (Automated Water Extraction Index). The water surface area of Lake Limboto changes every year, starting in 1990 with an area of 1,976 Ha, increasing in 2000 to 2,039 Ha, and the widest inundation of water surface in 2002 was 2,889 Ha, a decrease occurred in 2009 to 2,498 Ha, to become 1,843 Ha in 2020. The objects above the water surface also change yearly, from 6% in 1990-2000, increasing to 10% in 2009, reaching a 16% increase in 2014, and decreasing to 9% in 2020. This changing trend can be used as the basis for government policies in the management of Limboto Lake.

Monitoring Variasi Spasial dan Temporal Genangan Danau Limboto Selama 2000-2015 Menggunakan Citra Modis dan Google Earth Engine

Changes in the Limboto Lake area can be monitored using remote sensing technology. Satellite imagery provides data regarding the surface area of the lake over a long period of time. However, conventional methods require large resources to process and analyze large remote sensing image data. This study utilizes geospatial information technology with the support of cloud computing to overcome these obstacles. The purpose of this study is to determine the inundation area of Lake Limboto from 2000 to 2015 and to analyze the trend of changes in inundation area over a 16 years period. The experimental results show a map of spatial and temporal changes in the inundation of Lake Limboto over 16 years. The trend of changes in the inundation area of Lake Limboto shows a decrease of 56.56 Ha every year. Further research needs to involve other factors such as rainfall and vegetation cover to see the effect of the inundation area of Lake Limboto.

Limboto Lake Band Land Rights Arrangements

This paper aims to examine the regulation of land use by the Limboto Lake community. This study uses an empirical juridical approach. The study results show that the regulation of land rights, especially land along the banks, has been regulated by the government and local governments, starting from laws and regulations, regional regulations, and other decisions. The existence of laws and regulations has given legitimacy to the state, in this case, the government, regarding the control and utilization of the land on the banks of the lake because the state legally owns the land on Lake Limboto. However, the fact is that the land on the banks of the lake has changed its function to become a community settlement. , making it difficult to carry out an inventory of the surrounding population. In order to prevent mismanagement or management that is not based on the rule of law, it is necessary to have clear and accurate boundaries regarding the allotment of areas/zones for various interests so that there is no overlap between the government and the land agency, considering that some community lands already have land rights (land certificate). Thus, an alternative solution to save the lake is establishing a zoning system.

Spatiotemporal mapping of inundation area at Lake Limboto in Gorontalo, Indonesia, using cloud computing technology

Monitoring activities on the dynamics of water shrinkage at Lake Limboto are essential to the lake’s ecosystem’s recovery. A remote sensing technology functions to monitor the dynamics of lake inundation area; this allows one to produce a comprehensive set of spatial and temporal data. Such complex satellite dataset demands extra time, greater storage resources, and greater computing capacity. The Google Earth Engine platform emerges as the alternative to tackle such problems. The present study aims to explore the capability of Google Earth Engine in formulating spatial and temporal maps of the inundation area at Lake Limboto. A total of 345 scenes of Landsat image on the study area (available during the period of 1989–2019) were involved in generating a quick inundation area map of the lake. The whole processes (pre-processing, processing, analysing, and evaluating) were automatized by using the Google Earth Engine interface. The evaluation of mapping result accuracy indicated that the average score of F1-score and Intersection over Union (IoU) was at 0.88 and 0.91, respectively. Moreover, the mapping results of the lake’s inundation area from 1989 to 2019 showed that the inundation area tended to decrease significantly in size over time. During the period, the lake’s area also shrank from 3023.8 ha in 1989 to 1275.0 ha in 2019. All in all, the spatiotemporal information about the changes in lake area may be treated as a reference for decision-making processes of lake management in the future.

Mercury, Lead, and Cadmium Heavy Metal Content in Water, Fish, and Sediment in Limboto Lake

Lake Limboto is the largest lake in Gorontalo province including 15 Lake baggage that will be restored by the government. Pollution occurring in Lake waters is an important issue that needs to get the attention of various parties. Research aims to determine the status of environmental quality of the area, reviewing heavy metals (Hg, Pb, Cd) in water fishes and sediments, knowing the correlation between the fish and sediment. Sampling method is performed on 12 sampling points specified in purpose sampling. The method of analysis is used with government regulation No. 82 year 2001 on water quality and pollution control, measurement of heavy metal concentration SNI 06-6992.2.2004 by using Atomic Absorption Spekphotometer (AAS). The mercury content (Hg) of water in the 0.0019-0.1216 ppm range has exceeded the limits based on quality standards, lead (Pb) ranges between 0.008-0.0463 ppm while cadmium levels (Cd) range 0.007-0.0085 mg/L in general the value difference between stations is not Much. The content of mercury heavy metals in fish 0.0079-0.0631 as well as the heavy metal content of Pb is 0054 mg/L while the cadmium (Cd) content 0.017-0.058 mg/L. The concentration of heavy metals Hg 5.81-5.72 mg/L, the average Pb heavy metal 0.5571 mg/L whereas the heavy metal cadmium 0.6190 mg/L. The correlation of heavy metal mercury with water is an index of 1.00 showing strong relationships while the correlation of the heavy metals Pb 0233 has a weak and negative relationship and the Cd heavy metal is the 0.019 that shows a low correlate.

Adaptive Governance Features from Stakeholder Issues in Lake Limboto Management

This study aims to examine adaptive governance aspects of the issues from each stakeholder related to the management of Limboto Lake. The implementation of this research uses a qualitative deductive approach. The types of research that will be used are descriptive and explanative types. Sources of data from this research, namely documents and archival records grouped into documentation sources, interviews sourced from people/informants, and direct observation, observation of the role of physical devices grouped in observation sources, and Focus Group Discussions (FGD). The results of this study indicate that efforts to revitalize, rehabilitate and conserve are, of course, not the task of the Government alone but require the participation of the community in them. Conditions of good synergy between the Government, the community and the private sector in efforts to save and manage Lake Limboto are desirable, this is also in line with the achievement of the objectives of adaptive governance in terms of resilience to rapid and unpredictable environmental changes.