Search

Lake Taal is one of the most significant lake ecosystems in tropical East Asia. In 2011, a review paper consolidated all known biodiversity and limno-ecological studies conducted in Lake Taal from the beginning of the 20th century all the way to the late 2000s. It highlighted that insufficient funding, inadequate long-term monitoring data, and the publication culture of that time impeded having a comprehensive understanding of the lake. Since then, much research work has been done in Lake Taal, especially during the past decade. This review paper provides an analysis and summary of the research work conducted in Lake Taal over the past 10 years. The recent decade has seen a steady increase in scientific interest in Lake Taal made evident by more scientists and institutions working on topics involving the lake. Research grants, collaborations, and publications have also significantly increased during the past 10 years. This has led to an improved understanding of the lake's biodiversity, ecology, and impacts of intensive aquaculture and the introduction of non-native species. Taken together, this paper presents a better understanding of Lake Taal, which can be utilized for the design and improvement of conservation, preservation, and management programs for this multi-use freshwater system. [ABSTRACT FROM AUTHOR]

A floristic study of the diatoms (Bacillariophyceae) along the Marikina River in the eastern part of Metro Manila, Philippines, recorded at least 140 species belonging to 39 genera. Of these genera, one of the greatest number of species was observed in the genus Gomphonema (18 species). These species were identified and described under the bright field light microscope. Some species were further observed under the scanning electron microscope. A habitat description of the occurrence of the Gomphonema species is given. Twelve (12) out of the 18 species are new records for the country: G. brasiliense subsp. pacificum Moser, Lange-Bertalot & Metzeltin, G. chinense Liu & Kociolek, G. contraturris Lange-Bertalot & E.Reichardt, G. cuneolus E.Reichardt, G. exilissimum (Grunow) Lange-Bertalot & E.Reichardt, G. insigniforme E.Reichardt & Lange-Bertalot, G. javanicum Hustedt, G. kobayasii Kociolek & J.C.Kingston, G. pseudosphaerophorum H. Kobayasi, G. sundaense E.Reichardt, G. cf. qingyiensis L-X Zhang, P. Yu & Q-M You, and G. vibrio var. bohemicum (Reichelt & Fricke) R. Ross. Hence, this paper reports a total of 44 species of Gomphonema from the Philippines, including previous studies from 1937 to date. [ABSTRACT FROM AUTHOR]

Sponge-microbe symbiosis is considered among the most primitive ecological relationships between metazoans and microorganisms. There is strong interest in understanding the occurrence of microbial communities in sponges due to their integral roles in host ecology, nutrient cycling, and production of potential bioactive secondary metabolites. However, most studies on sponges have been centered on marine species. In this study, the freshwater sponge Spongilla alba and its associated microorganisms were explored for the first time. Sponge samples collected from Lake Taal were taxonomically identified using gross morphology and spicules analysis. Both bacterial and fungal isolates were culturally characterized and molecularly identified using 16S rRNA gene for bacteria and ITS for fungi. Five bacterial species were identified as Pseudomonas sp., Enterococcus sp., Stenotrophomonas sp., Stenotrophomonas maltophilia, and Pseudomonas mosselii plus eight fungal species with spore sizes from 5-10 μm were identified as Colletotrichum truncatum, Trichosporon asahii, Rhizopus microsporus, Puccinia striiformis f. sp. tritici strain, Talaromyces columbinus, Phoma sp., Phomopsis sp., and Lichtheimia ramosa. Phylogenetic analysis revealed microbial sequences belonging to Proteobacteria (n = 4), Firmicutes (n = 1), Ascomycota (n = 4), Zygomycota (n = 2), and Basidiomycota (n = 2). The study reports infrequent occurrences of Enterococcus, Stenotrophomonas, Puccinia, and Lichtheimia species as freshwater sponge-associated microbes. This also presents the culturable microbial composition of freshwater sponges and rare occurrence of marine- and terrestrial-associated fungi T. asahii, R. microsporus, Phoma sp., Phomopsis sp., C. truncatum, and T. columbinus in a unique freshwater ecosystem such as Lake Taal. [ABSTRACT FROM AUTHOR]

The presence of the invasive calanoid copepod Arctodiaptomus dorsalis in Philippine inland waters has been reported in numerous studies. Attempts to understand how it effectively proliferated in the country's freshwaters have shown its preference towards shallow and productive waters - a feature shared by most lakes in the Philippines. In this study, we compared the body size and reproductive capacity - proxied by clutch size (CS) - of ovigerous female A. dorsalis obtained from established populations in the seven maar lakes (SML) of San Pablo, Laguna, Philippines. These measurements were also correlated with selected water quality parameters. Collection of ovigerous A. dorsalis and water quality parameters were conducted on a 3-mo sampling period during the southwest monsoon season in 2016. Statistical analysis shows that there exists a significant difference between the prosome length (PL) and CS of A. dorsalis from the seven lakes (p < 0.001), with the shallowest and most productive lake containing the most fecund population. Additionally, all water quality parameters showed a positive correlation with the PL and CS of ovigerous A. dorsalis from the SML (p < 0.01). This shows that the SML provides favorable conditions for the propagation of A. dorsalis, making it a model for in situ investigation of this invasive species' ecology; the first step in incorporating zooplankton ecology as a tool for the development of lake management systems. [ABSTRACT FROM AUTHOR]

Relatively limited information exists on Lake Wood's limnology and ecology, an ancestral lake of the Subanens. Here, we provide a limnological characterization of the lake -- exploring its physical, chemical, and biological features. The data on lake morphometry were gathered using an echosounder; lower depth water samples were collected using a Niskin water sampler for physicochemical analyses while surface water samples were collected at five sampling sites for phosphate (PO4) analysis; and zooplankton samples were collected at several depths through vertical towing in March-April 2019. Lake Wood, located at 320 m above sea level, has an extensive surface area covering 7.38 km² with a maximum depth of 85 m. Lake water comes from rainfall, small rivers, and groundwater and empties into the Dumanquilas Bay via its only outlet -- the Biswangan River. Land use of the lake is predominantly cultivated land. Moreover, based on the trophic state index (TSI), the lake's current trophic status is eutrophic. During the study periods, thermocline and oxycline formed at 15 m below the surface of the lake. We recorded three cladocerans (Ceriodaphnia cornuta, Diaphanosoma cf. sarsi, and Moina micrura) and one copepod species (Thermocyclops crassus) in the lake, all of which are common limnetic species found in the Philippines. Based on our findings, we recommend more efforts to manage and rehabilitate the lake to control and manage eutrophication's negative impacts. Finally, our study contributes to understanding lakes in Mindanao that are less represented in Philippine freshwater research. [ABSTRACT FROM AUTHOR]

In developing countries such as the Philippines, the inadequacy of even the most basic limnological datasets available has hindered planning and implementation of science-based management policies for inland waters. This situation is aggravated by overutilization of natural resources for ecosystem services such as water usage, aquaculture, fishing, and tourism. We reviewed published researches related to the Seven Maar Lakes (SMLs) in Luzon Is., Philippines to summarize information invaluable for the protection and sustainable use of these resources. Popular scientific search engines were utilized to gather peer-reviewed research articles and reports from both private institutions and government agencies. Literature and timeline from the 1930s to 2019 was classified into topics – namely socioeconomics, fisheries, biodiversity, and environment. Based on the literature survey, a variety of challenges, knowledge gaps, and promising research directions were identified, which are essential to the sustainable ecosystem management of the SMLs. Aquaculture practices impacting the lakes and its underestimated biodiversity were described. Measured vertical profiles of dissolved oxygen (DO), temperature, conductivity, pH, and salinity was supplemented by our preliminary limnological survey in the SMLs. Past and present monitoring data of selected physicochemical parameters were assessed from which the changing limnological status of the lakes was determined. We recommended measures motivated by strategic environmental assessments while still considering maintained economic yields. A sustained collaborative effort from different sectors is strongly suggested not only to manage the SMLs but also to address trade-offs among critical ecosystem services. Aside from the need for well-designed, long-term water quality monitoring, we also stress the synergistic interpretation of all available knowledge, which can contribute to the resolution of environmental issues at both local and global scales. [ABSTRACT FROM AUTHOR]