Laguna Lake Research Articles

Bioanalytical Monitoring of Laguna Lake (Philippines) to Assess Water Research Priorities Associated with Organic Chemical Pollution and Cyanobacterial Blooms

Bioanalytical Monitoring of Laguna Lake (Philippines) to Assess Water Research Priorities Associated with Organic Chemical Pollution and Cyanobacterial Blooms

Predictive Functional Profiling Reveals Putative Metabolic Capacities of Bacterial Communities in Drinking Water Resources and Distribution Supply in Mega Manila, Philippines

Assessing bacterial communities across water resources is crucial for understanding ecological dynamics and improving water quality management. This study examines the functional profiles of bacterial communities in drinking water resources in Mega Manila, Philippines, including Laguna Lake tributaries, pre-treatment plant sites, groundwater sources, and post-treatment plant sites. Using eDNA sequencing, flux balance analysis, and taxonomy-to-phenotype mapping, we identified metabolic pathways involved in nutrient metabolism, pollutant degradation, antibio- tic synthesis, and nutrient cycling. Despite site variations, there are shared metabolic pathways, suggesting the influence of common ecological factors. Site-specific differences in pathways like ascorbate, aldarate, and phenylalanine metabolism indicate localized environmental adaptations. Antibiotic synthesis pathways, such as streptomycin and polyketide sugar unit biosynthesis, were detected across sites. Bacterial communities in raw and pre-treatment water showed potential for pollutant degradation such as for endocrine-disrupting chemicals. High levels of ammonia-oxidizing and sulfate-reducing bacteria in pre- and post-treatment water suggest active nitrogen removal and pH neutralization, indicating a need to reassess existing water treatment approaches. This study underscores the adaptability of bacterial communities to environmental factors, as well as the importance of considering their functional profiles in assessing drinking water quality resources in urban areas.

Bacterial community profiles of select tributaries of Laguna Lake in the Philippines.

Laguna Lake is known for its ecological, economic, and cultural importance. Effects of urbanization and accumulation of emerging pollutants have been associated with its water quality; however, the microbial ecology of its tributaries remains to be explored. We report bacterial community profiles from shotgun metagenomes of its select tributary waters.

Geostatistical Exploration of Some Water Quality Clusters in Laguna Lake, Philippines

Geostatistical Exploration of Some Water Quality Clusters in Laguna Lake, Philippines

INVESTIGATION OF THE EFFECT OF SPACE VARYING WIND INPUT ON HYDRODYNAMIC MODELING IN MANILA BAY AND LAGUNA LAKE

Abstract. Surface water currents and waves are largely driven by wind forcing by inducing shear stress to the water surface. The circulations formed carry with it various materials and pollutants all over a large body of water like the Manila Bay and Laguna Lake. Considering the spatial and temporal variability of wind over the Bay and the Lake is essential to model the hydrodynamics of water more accurately. This study simulated bay hydrodynamics using high resolution space- and time-varying wind data from Weather Research Forecasting (WRF) as input and compared the results with using uniform-directed wind. The downscaled winds from WRF demonstrated patterns in agreement with the country’s seasonal monsoon wind dynamics. Its effect on the bay hydrodynamics is more pronounced during the dry season as it changes the flow direction of water at the bay mouth. On the other hand, the hydrodynamic difference in circulation patterns for the lake was accentuated with a more defined clockwise gyre circulation during the wet season where prevailing winds are stronger. Thus, it is imperative to incorporate spatially varying wind input to accurately characterize the bay water movement. Results also showed that global weather inputs can be used in areas with scarce monitoring stations as long as they are validated.

Hydrodynamic Investigation of Laguna Lake, Philippines for Water Security and Flood Risk Management of Metro Manila

Abstract. Laguna Lake, strategically located at the center of urban development, Metro Manila, is the focal point of national development efforts for economic activities, including flood disaster operation. It is the most stressed inland water body at the same time however, with competing and conflicting water-users, and continued environmental degradation from anthropogenic-based stressors. The use of the lake as a source of raw water for domestic supply have become more significant and critical over the past recent years with the aggravating condition of water scarcity in Metro Manila. It also serves as an important flood-detention storage for Metro Manila during the rainy season, with flow diversions from upstream Marikina river basin. This study presents a three-dimensional hydrodynamic study of Laguna Lake to understand the physical processes that govern and influence lake hydraulics for various water uses. A hydrodynamic model was set-up incorporating spatial and temporal variations in wind forcing and watershed river discharges, and dynamic sea interaction. Simulation results reveal a significant increase in lake salinity concentration for incremental increases in lake water abstraction, particularly during the dry season. A numerical experiment on bathymetric evolution also showed various Pasig River hydraulic discharge features and an increase in hydraulic residence time of the lake. Modelling analysis on the lake's flood detention function on the other hand revealed different shore-land flood inundation areas and recession durations for varying lake-flood detention levels that warrants the need for a more comprehensive and sustainable flood management operation in the metropolis. Results from this study substantiate scientific information for outlining management approaches and conservation strategies especially for fast developing environments.

Status Trofik Perairan Danau Laguna, Kota Ternate Selatan, Maluku Utara

Water quality and trophic status of waters play an important role in aquaculture activities because they will affect the growth process of cultivated fish, if the water quality and trophic status are low then they can support aquaculture activities in the waters of Laguna Lake, South Ternate City. The purpose of this study was to determine the water quality and trophic status in the waters of Laguna Lake in supporting and supporting freshwater aquaculture activities. The research method used in this research is descriptive qualitative, the results of air analysis are described based on Class and Water Quality Standards, while the trophic status is estimated based on Carlson, 1977. The results of the analysis show that the water quality in Laguna Lake is still in accordance with Class II Quality Standards. PP No. 22 of 2021, while the trophic level status in Laguna Lake is also classified in the oligotrophic category, namely TSI <40, TSI in Laguna Lake waters ranges from 20.69-23.28. Based on the results of the analysis of water quality and trophic status, it was found that the waters of Laguna Lake are still good and can support freshwater fish farming activities

Evaluating Environmental Awareness in Practice on the Concept of Nutrient Cycling Among Senior High School Students

Nutrient cycle, a concept that highlights the path that nutrients follow as they travel from the soil to the plant and other organisms, is an important concept for students to understand since it connects human actions to their effects on the environment. Understanding how the nutrient cycle works, especially in the context of lake water, is crucial in managing ecosystems effectively and mitigating the impacts of pollution, especially when it is because of anthropogenic causes. Therefore, there is a need to integrate environmental education into class lessons so that society can fully grasp the relationship between science and society. This study surveyed a total of 110 students from three different schools using simple random sampling. These schools near Laguna Lake of Los Baños, Laguna were randomly selected. Schools near the lake were targeted because they were relatively familiar with the topic. The survey assessed environmental awareness in three categories: knowledge, attitude, and practice, validated through Cronbach’s Alpha test. From the data collected the respondents were found to have low awareness in terms of knowledge (44.6%), high awareness in terms of attitude (83.6%), and a moderately low awareness in terms of practice (67.6%). This suggests a need to enhance student understanding of environmental concepts and issues to improve their practices. Thus, motivating them in adopting sustainable practices. Overall, the results from this study support the premise that there is a need to create teaching materials and activities to improve the practices of the students.

Microalgal diversity assessment of Laguna Lake (Philippines) tributaries using Next-Generation Sequencing for water quality

Abstract. Santos JA, Mejia JA, Galarion MAJ, Vital P. 2023. Microalgal diversity assessment of Laguna Lake (Philippines) tributaries using Next-Generation Sequencing for water quality. Biodiversitas 24: 4636-4644. The species composition and density of microalgae have been successfully used as bioindicators of water quality as they respond quickly to any change in the water chemistry brought about by pollution. Laguna Lake in the Philippines, one of the country's most important hotspots for aquaculture, continues to be threatened by eutrophication, yet its microalgal profile has been understudied. The presence of microalgae, especially those identified to become causative agents of harmful algal blooms in lakes, can cause corresponding health effects in humans and the environment. This study determined microalgal diversity in samples from tributaries of Laguna Lake, Philippines, through 18S rRNA metagenomic sequencing or Next-Generation Sequencing (NGS). Out of the five sampling sites, only two sites passed the NGS quality control pipeline. Chlorella M.Beijerinck, dominated the eukaryotic microbial population in the Alabang-Cupang River sample, which is 95% of the total population. While in the Biñan River sample, relevant species found were Cyclotella scaldensis Muylaert & Sabbe, Teleaulax acuta (Butcher) Hill, Cryptomonas curvata Ehrenb., and Peridiniopsis penardii (Lemmerm.) Bourr. This is the first study to use NGS to detect microalgae in Laguna Lake and warrants further elucidation of the microalgal population through increased sampling efforts in other recreational and livelihood hotspots. Furthermore, the study results open the importance of implementing new schemes for water quality assessments focused on molecular-based approaches.

Water Quality Index as a tool for assessing the water quality of the Laguna de Bay from 2020 to 2021

Laguna de Bay (LdB) is a primary freshwater resource that provides multiple ecosystem services. The Laguna Lake Development Authority (LLDA) oversees the periodic monitoring of LdB’s water quality. Data collected by the LLDA can be used to assess LdB’s status using an easily understandable metric. In this study, Water Quality Index (WQI) was used to assess LdB’s quality based on seven parameters (fecal coliform, nitrate, inorganic phosphate, ammonia, biochemical oxygen demand, dissolved oxygen, and pH) measured and recorded by the LLDA from 2020 to 2021. Data from eight major monitoring stations were used to explore how the seven parameters link the stations as well as to compute the WQIs. The lowest WQIs (excellent quality) were obtained using the data representing the end of 2020 for all eight stations, while the highest WQIs (good - poor quality) were obtained for the data measured towards the end of 2021 for Stations I, II, and XVI. Principal Component Analysis (PCA) revealed that the stations had relatively similar environmental influences and overall water quality. Station groupings correspond with the computed WQIs. Stations that had unconventional placements in the biplots (Q3-Q4 of 2021 for Stations I and XVI and Q2 of 2021 for Station V, classified as outliers), correspond to the time points where the lowest water quality was noted. Overall, WQI values are concordant with the water and land use type of the stations. WQI is a useful tool for indicating water quality and is valuable in evaluating LdB and other freshwater resources.

Host-Associated Bacteroides 16S rDNA-Based Markers for Source Tracking of Fecal Pollution in Laguna Lake, Philippines.

Sources of fecal contamination in Laguna Lake, Philippines, were identified using a library-independent microbial source tracking method targeting host-associated Bacteroides 16S rDNA-based markers. Water samples from nine lake stations were assessed for the presence of the fecal markers HF183 (human), BoBac (cattle), Pig-2-Bac (swine), and DuckBac (duck) from August 2019 to January 2020. HF183 (average concentration = 1.91 log10 copies/mL) was the most frequently detected, while Pig-2-Bac (average concentration = 2.47 log10 copies/mL) was the most abundant. The detected marker concentrations in different stations corresponded to the land use patterns around the lake. Generally, all marker concentrations were higher during the wet season (August-October), suggesting the effect of rainfall-associated factors on the movement and retention of markers from sources. There was a significant association (ρ = 0.45; p < 0.001) between phosphate and the concentration of HF183, suggesting domestic sewage-derived pollution. The markers had acceptable sensitivity and specificity, i.e., HF183 (S = 0.88; R = 0.99), Pig-2-Bac (S = 1.00; R = 1.00), and DuckBac (S = 0.94; R = 1.00), and therefore may be used for the continuous monitoring of fecal pollution in the lake and in designing interventions to improve the quality of the lake water.

Microplastics in Northern Laguna Lake’s Shoreline Sediments

Microplastic pollution, a pervasive problem in the natural environment, is hardly investigated in the largest lake in the Philippines: Laguna de Bay or Laguna Lake. This study was done to determine the microplastic profile (content and type) of the shore sediments taken from northern Laguna Lake and to identify possible sources of the microplastics found. The microplastics from the sediments were extracted and isolated using the chemical oxidation and density floatation method. To identify the possible microplastic source, a comparison of Fourier transform infrared (FTIR) spectra of the microplastics extracted with sample plastic materials found on the sites was done. Results showed that during the dry season, the mean microplastic contents of Binangonan, Tanay, and Angono sediments were 1524.42 ± 1593.45, 815.41 ± 593.64, and 295.51 ± 140.16 microplastics per kg sediment, respectively. During the wet season, the mean microplastic contents of the sediments in Binangonan, Tanay, and Angono were 1826.05 ± 614.19, 1250.73 ± 220.03, and 353.82 ± 173.07 microplastics per kg sediment, respectively. The variations observed with season might be associated with tidal and current effects on the shoreline sediments and not due to changes from the dry to the wet season. FTIR analysis of microplastic type showed that prominently occurring microplastics in the three towns varied depending on the materials associated with human activities such as fish farming (aquaculture), clothing materials, and plastic packaging. The results of this study show significant implications on the effect of anthropogenic activities on the type and abundance of microplastics found in the environment, and knowledge of the microplastic profile in Laguna Lake could help not only in its clean-up but also in the proper disposal of plastics in the area to prevent its presence in the natural environment.

The Government and Lake Governance Criteria for the Seven Crater Lakes of San Pablo City, Laguna, Philippines

AbstractThe Local Government and the Government Agency shape the Seven Crater Lakes. The present study focused on understanding the predominant Governments and Lake Governance's concept vis‐a‐vis the small lakes and their basin communities. These foremost authorities are intertwined, and Lake Governance's essential criteria interplayed and continuous to the responsibility. Although the City Government of San Pablo City and the Laguna Lake Development Authority (LLDA) have improved the small lake's situations and they are satisfactorily functioning, serious issues still remain at present and into the future. Focusing on the criteria's lessons, Pandin Lake, Yambo Lake, Mohicap Lake and Sampaloc Lake have been ameliorated to varying degrees. In contrast, Bunot Lake, Palakpakin Lake and Calibato Lake continue to struggle with deficiencies. Thus, over the dual governments need to exhibit greater commitment, decisiveness and effectiveness if the Seven Crater Lakes are to flourish in development and conservation. Furthermore, while the Structuring Government and Administering Water criteria are adequate, completing the Developing Tourism, accomplishing the Regulating Fishery and substantially subsidizing the Supporting Finance in the City Government and the LLDA remain deficient. Accordingly, the main target of the paired Governments' over time is to address the remaining challenges facing the Seven Crater Lakes.

Determination of Perfluorooctanoic Acid and Perfluorooctane Sulfonate Water Quality Criteria for Ecosystem Protection of Laguna Lake, Philippines

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are organic chemicals which pose concerns in the environment due to their persistence and bioaccumulative properties. This study used Assessment Factors and Species Sensitivities Distributions to derive specific thresholds to protect the ecosystem in the Laguna Lake, Philippines from risks posed by the toxicity of PFOS and PFOA using available ecotoxicity data for local species. For Assessment Factor method, the U.S. Environmental Protection Agency guideline for the narrative Tier II criteria was suitable based on the available toxicity data with calculated maximum concentration threshold for PFOS and PFOA of 0.51 and 0.75 mg L-1, respectively, and continuous maximum concentration values of 0.06 and 0.08 mg L-1, respectively. For the methods using Species Sensitivity Distribution (SSD), PFOS and PFOA thresholds extrapolated using factors for small datasets were 0.046 and 0.088 mg L-1, respectively. Lastly, PFOS and PFOA Hazardous Concentration (HC5) extrapolated from the weighted average SSD model estimates were 0.061 and 0.078 mg L-1, respectively. The results can serve as the first regulatory and risk assessment basis for aquatic ecosystem protection against risks posed by emerging contaminants in the lake.

Spatial and temporal variation of aseismic creep along the dilational jog of the West Valley Fault, Philippines: Hazard implications

Accelerated creep, primarily through vertical displacement, has been occurring along 15 en-echelon faults belonging to a 15 km-long and 1.5 km-wide, N-S-trending dilational jog of the active West Valley Fault (or West Marikina Valley Fault), on the southeastern part of Metro Manila, Philippines. The much-larger-than-known tectonic slip rates had been the only reliable evidence in support of excessive groundwater withdrawal as the trigger of creep in the 1990s. Recently available groundwater extraction data (1977–2019) could more directly and consistently link groundwater withdrawal to accelerated creep in the 1990s. Twenty years (1999–2019) of precise displacement measurements could also reveal significant spatial and temporal links between slip rate changes and patterns of groundwater extraction. Our analysis shows that greater rates of vertical displacement are related to the timing of faster extraction rates. Variations in slip rates between the northern and southern measurement sites are primarily due to regional differences in groundwater extraction, which are influenced by differences in the implementation of water extraction reduction regulations. Proximity to the key source of groundwater recharge (Laguna Lake) is also an influencing factor. Although there are many unknowns inherent to this type of study, continued depressurization could induce static stress changes that could modulate the timescale of earthquake occurrence due to the natural course of stress loading driven by regional tectonics. The current and potential effects of continued depressurization in the areas with high slip rates and surrounding regions are paramount considerations in crafting and implementing tighter and extended groundwater extraction regulations.

Simulation of Urban Heat Island during a High-Heat Event Using WRF Urban Canopy Models: A Case Study for Metro Manila

This present study aims to determine the performance of using the Weather Research and Forecasting (WRF) Model, coupled with the urban canopy models (UCMs), in simulating the 2 m air temperature and 2 m relative humidity in Metro Manila. The simulation was performed during a high heat event on 22–29 April 2018, which coincided with the dry season in the Philippines. The four urban canopy model options that were used in this study include, the bulk (no urban), SLUCM, BEP, and BEM. The results of the simulations were compared with the hourly observations from three weather stations over Metro Manila from the National Oceanic and Atmospheric Administration Integrated Surface Dataset (ISD) and one agrometeorological station in Naic, Cavite. After model validation, the urban heat island (UHI) was then characterized to determine the spatial-temporal variations in the cities of Metro Manila. Statistical results show that the WRF simulation for 2 m air temperature agrees with measurements with an RMSE of &lt;3.0 °C, mean bias error of &lt;2.0 °C, and index of agreement of &gt;0.80. WRF simulation for relative humidity still presents a challenge where simulation errors are higher than the acceptable range. The addition of UCMs does not necessarily improve the simulation for 2 m air temperature, while the use of BEP improved the 2 m relative humidity simulation. The results suggest the importance of using actual urban morphology values in WRF to accurately simulate near-surface variables. On the other hand, WRF simulation shows the presence of urban heat islands, notably in the northwest and central area of Metro Manila during daytime, extending throughout Metro Manila during nighttime. Lower air temperature was consistently observed in areas near Laguna Lake, while higher air temperature due to stagnant winds was observed in the northwest area of Metro Manila. High heat index was also observed throughout Metro Manila from daytime until nighttime, especially in areas near bodies of water like Manila Bay and Laguna Lake due to high humidity.

Fishers’ Perspectives: the Drivers Behind the Decline in Fish Catch in Laguna Lake, Philippines

Aquatic ecosystems are strongly affected by global change. Fishers hold local ecological knowledge (LEK) that is especially relevant for improving our understanding of aquatic ecosystems that experience major environmental changes while also providing crucial ecosystem services. This research explores the perceptions of the ecological changes in Laguna Lake (Philippines) among local fisherfolks. In 2019, we conducted 30 semi-structured interviews with fisherfolks with up to 60 years’ experience. They reported catching 31 fish species and one shrimp genus as a staple food and income source, with more than one-third of the species being exotic or introduced. The fisherfolks noted repeated fish kill events and dramatic changes in their catch such as fewer and smaller fish. Also noticeable were the widespread catch of knifefish, a comparably newly introduced species, and the fact that all native fish species were reported to be less often caught now than in the past. This included the reduced catch of talilong (mullet), dalag (snakehead), and ayungin (silver perch). Locals emphasized various drivers behind these changes, which are linked to one another in complex interrelationships. Invasive species, the deterioration of fish habitats, and increased water turbidity were cited as the main drivers. Interviewees highlighted an additional link between declining catches and the loss of aquatic plant diversity, which has been understudied in Laguna Lake and has not been the focus of regional policy efforts. The empirical evidence provided by the fisherfolks enhances earlier existing scientific evidence of this aquatic ecosystem as well as highlights the importance of contributions coming from different knowledge systems.

Advocating the Urban Nexus of Water, Food and Energy through Laguna Lake: The Case of Sta. Rosa

Sta. Rosa, Laguna, Philippines is part of the project Integrated Resource Management in Asian Cities: The Urban Nexus commissioned by the German Federal Ministry for Economic Cooperation and Development (GIZ) in a term from 2013-2015. The Urban Nexus was created to tackle issues on the exhaustion of land, food, water, energy, and sanitation caused by the ever-rising Asian population. This is a pressing issue in the local and international scene but due to its immediate accessibility to people, municipalities have the advantage of solving the problems upfront. Still, due to the departmental management system, typical in Asian countries, municipalities have “struggled to make the most of the opportunity” for the community according to World Bank (Ellis, et. al., 2016). Municipalities in Asia are managed through divisions, Sta. Rosa, as an example, has 27 departments, 15 assistant departments and 10 other departments under the office of the mayor (Municipality of Sta. Rosa, 2021). This type of system solves problems under their department as a single, disconnected element thus blurring the impact and interrelationships or nexus of water, food, and energy. This paper adds to the limited studies that analyse the implementation, progress, and measurements of The Urban Nexus. Drawn from a multiple case study approach, results showed that there was no tangible effect of The Urban Nexus project 6 years after its execution, specifically to those who will benefit the most – the informal settler families along Laguna Lake in Sta. Rosa. And because it takes dedication from all levels of the society to participate and perform their roles to achieve the urban nexus, recommendation of the interconnected responsibilities of schools to municipalities are described.

Multiple Antibiotic Resistance in Escherichia coli Isolates from Fecal and Water Sources in Laguna Lake, Philippines

Due to the misuse and overuse of antibiotics, antibiotic residues accumulate in natural environments, leading to the development of antibiotic-resistant bacteria (ARBs). The presence of ARBs in bodies of water poses health hazards to the surrounding community. This study focused on Laguna Lake, the largest lake in the Philippines, which serves as a water source for agriculture and domestic purposes. We aimed to detect the presence of antibiotic-resistant Escherichia coli from the lake waters and potential reservoirs of resistance as well as determine the multiple antibiotic resistance (MAR) indices of the isolates. E. coli (n = 450) was isolated from fecal-associated samples (chicken, cow, pig, human, sewage) and water samples (sites in Laguna Lake and selected river tributaries). The isolates were subjected to an antibiotic resistance assay using VITEK 2®. Among the 16 antibiotics tested, the isolates exhibited varying resistance to 14, but complete susceptibility to amikacin and tigecycline was observed. Isolates were most frequently resistant to ampicillin (196/450, 43.6%). Among fecal-associated samples, chicken isolates exhibited the highest MAR index (0.174), whereas samples from Pila River exhibited the highest MAR index (0.152) among water samples. The results of this study demonstrate the presence of multidrug-resistant E. coli in samples collected around Laguna Lake and reveal fecal and sewage sources as potential reservoirs of ARBs in the water body. With this information, the public is urged to use antibiotics responsibly to help mitigate the spread of antibiotic resistance.

MODELLING THE CHLOROPHYLL-A CONCENTRATION OF LAGUNA LAKE USING HIMAWARI-8 SATELLITE IMAGERY AND MACHINE LEARNING ALGORITHMS FOR NEAR REAL TIME MONITORING

Abstract. Recent studies have investigated the use of satellite imaging combined with machine learning for modelling the Chlorophyll-a (Chl-a) concentration of bodies of water. However, most of these studies use satellite data that lack the temporal resolution needed to monitor dynamic changes in Chl-a in productive lakes like Laguna Lake. Thus, the aim of this paper is to present the methodology for modelling the Chl-a concentration of Laguna Lake in the Philippines using satellite imaging and machine learning algorithms. The methodology uses images from the Himawari-8 satellite, which have a spatial resolution of 0.5–2 km and are taken every 10 minutes. These are converted into a GeoTIFF format, where differences in spatial resolution are resolved. Additionally, radiometric correction, resampling, and filtering of the Himawari-8 bands to exclude cloud-contaminated pixels are performed. Subsequently, various regression and gradient boosting machine learning algorithms are applied onto the train dataset and evaluated, namely: Simple Linear Regression, Ridge Regression, Lasso Regression, and Light Gradient Boosting Model (LightGBM). The results of this study show that it is indeed possible to integrate algorithms in Machine Learning in modelling the near real-time variations in Chl-a content in a body of water, specifically in the case of Laguna Lake, to an acceptable margin of error. Specifically, the regression models performed similarly with a train RMSE of 1.44 and test RMSE of 2.51 for Simple Linear Regression and 2.48 for Ridge and Lasso Regression. The linear regression models exhibited a larger degree of overfitting than the LightGBM model, which had a 2.18 train RMSE.