MULTITEMPORAL ANALYSIS FOR TROPHIC STATE MAPPING IN BATUR LAKE AT BALI PROVINCE BASED ON HIGH-RESOLUTION PLANETSCOPE IMAGERY

Remote sensing data for analyzing and evaluating trophic state ecosystem problems seen in Batur Lake isan approach that is suitable for water parameters that cannot be observed terrestrially. As the multitemporal spatial data used in this study were extensive, it was necessary to consider the effectiveness and efficiency of the processing and analysis, therefore R Studio was used as a data processing tool. Theresearch aims to(1) map the trophic state of Batur Lake multitemporally usingPlanetScope Imagery;(2) assess the accuracy of the trophic state model and applyitto anothertemporal data as a SpatialBigData;and (3) understand the trophic state impacton the water quality of Batur Lake based on physical factors andthelake’s chemical concentration (sulfur concentration). Theresearch showsthatthetrophic state of Batur Lake isin good condition,with an ultraoligotrophic state as the majority class,based on the mean Trophic State Index (TSI) value of9.49. The standard errorsof each trophic state parameter were0.010 for total phosphor, 0.609 for chlorophyll-a, and 0.225 for Secchi Disk Transparency (SDT). The multitemporal model demonstratesthat the correlation between the increase oftrophic state and mass fish death cases in Batur Lake is existent.

Monitoring spatiotemporal variability of water quality parameters Using Landsat imagery in Choghakhor International Wetland during the last 32 years

Use of Landsat is of importance in monitoring and assessment of long-term changes of water quality in freshwater ecosystems, especially in small water bodies. In this study, over a 32-year period (1985–2017), the changes in water surface temperature (WST), secchi disk transparency (SDT), and chlorophyll-a (Chl-a) concentration were estimated at the Choghakhor wetland using Landsat imagery. Based on WST three detectable temperature zones can be observed within the wetland aquatic environment where the highest amount was observed in thermal strips. The results showed Chl-a concentration volatility in different periods in the wetland as well as its long-term increasing trend. The western part of the wetland, as compared to other areas, was affected by these changes, which could be due to the human activity concentrated in this area. In contrast (SDT) showed a decreasing trend during this period that was consistent with the observed changes in Chl-a concentration. This could be due to an increase in organic matter load and suspended solids in the water body of wetland during this time. Comparison of the extracted satellite data with the field data showed the least RMSE and high R2. Also, ANOVA results showed significant spatio-temporal differences between the studied parameters in Choghakhor wetland (p < 0.05). The present study can help to detect long-term changes in Choghakhor wetland and help toward moving to optimal management and protection of this wetland.

Predicting chlorophyll-a concentrations in two temperate reservoirs with different trophic states using Principal Component Regression (PCR)

Relationships between chlorophyll-a (chl-a) concentrations and 16 physicochemical variables in temperate eutrophic Çygören and mesotrophic Ikizcetepeler reservoirs (Turkey) were determined using Principal Component Analysis (PCA). PCA was used to simplify the complexity of relationships between water quality variables. Principal component scores (PCs) were used as independent variables in the multiple linear regression analysis (MLR) to predict chl-a in both reservoirs. This procedure is called Principal Component Regression (PCR). In the eutrophic Çygören Reservoir, chl-a was significantly (p < 0.05) correlated with nitrite-nitrogen (NO2), ammonium-nitrogen (NH4), phosphate (PO4), total suspended solids (TSS), pH, Secchi disk transparency, total dissolved solids (TDS) and total phosphorus (TP). In the mesotrophic Ikizcetepeler Reservoir, chl-a was significantly (p < 0.05) correlated with TSS, NO2, chemical oxygen demand (COD), sulfate (SO4), TDS, pH and the Secchi disk. In the eutrophic Çaygören Reservoir, six PCs explained 71% of the total variation in the water quality, while in the mesotrophic Ikizcetepeler Reservoir, six PCs explained 75% of the variation. This study has shown that PCR is a more robust tool than direct MLR to simplify the relationships between water quality variables and to predict chl-a concentrations in temperate reservoirs with different trophic states.

Assessment of Water Quality and Trophic Status of Duhok Lake Dam

This study is conducted in order to, investigate the trophic state of Duhok Lake Dam located within Duhok city, Iraq. Water samples are collected seasonally from three monitored sites during 2011. The parameters used for assessing water quality and trophic status level include: water temperature, pH, EC, TDS, DO, BOD5, nutrients, Secchi disk transparency, and chlorophyll a. The results reveal that DO is above 5 mg.l-1 in all sites, BOD5 value is within permissible level for domestic uses. Water quality considered as a hard type. High sulfate concentration is recorded during the study period. Trophic state shows that water type is classified as mesotrophic during autumn season, while it is regarded as eutrophic in other seasons. TDN/TDP ratio suggests that phosphorus is a limiting factor for algal growth. Based on IWQI, the water type is classified as excellent type for irrigation purpose.

Monitoring of regional lake water clarity using Landsat imagery

The application of remote sensing technology to water quality monitoring has special significance for lake management at regional scale. Water clarity expressed in terms of Secchi disk transparency (SDT) is a highly useful indicator of trophic status and ecosystem health. In this study, we related Landsat TM and ETM+ data with ground observations to develop a model for the estimation of SDT which can be used as a standardized procedure for regional-scale lake clarity assessment in the central region of Argentina. Samples were taken from two reservoirs of the region. Pearson correlation coefficients and step-wise multiple regression analysis were used to evaluate correlation between Landsat bands and measured SDT. Results suggested that Landsat band 3 plus the ratio 1/3 was a consistent and reliable predictor of SDT (R2 = 0.80). The algorithm was validated (R2 = 0.81) and applied to the November 10, 2010 ETM+ image obtaining a map that characterized water clarity of reservoirs within the study area. The procedure presented here could become a low cost measurement tool for water management authorities and decision-makers, obtaining simpler and practical results for regional water clarity monitoring.

Water Quality Parameters and Bird Diversity in Jagdishpur Reservoir, Nepal

Water quality parameters were analyzed seasonally to examine relationships with bird numbers and species richness in Jagdishpur reservoir. This wetland is a Ramsar site and an important bird area (IBA) of Nepal. The trophic status of the reservoir was categorized as eutrophic as assessed by Secchi disk transparency (1.45 ± 0.53 m), total alkalinity (220.94 ± 85.52 mg/l) and total nitrogen (884.19 ± 291.61 ?g/l) concentrations. Direct count method detected a total of 77 bird species belonging to 8 orders and 31 families of which 40 species were resident and 37 migrants. Species richness ranged from 21(summer) to 74 species (winter). Secchi disk transparency showed a significant positive correlation with bird numbers ((r = 1.00, p < 0.01) whereas significant negative correlation was found between water temperature and species richness (r = - 0.97, p < 0.05). Absolute positive correlation between species richness and seasons was established (r = 0.74). The seasonal distribution pattern showed two peaks of species richness, Shannon diversity, equitability and evenness index, one in winter and the other in autumn. Fulica atra (30.53%), Dendrocygna javanica (15.88%) and Anas strepera (9.58%) were the three most dominant bird species. Fourteen CITES species, 8 globally and 14 nationally threatened species were recorded. Conservation action plan for threatened species that focuses on population monitoring, protecting key habitats and habitat enhancement is urgently needed. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 143-155 DOI: http://dx.doi.org/10.3126/njst.v13i1.7453

Total organic carbon as a new index for monitoring trophic states in lakes

Total organic carbon (TOC) can be one of the parameters used to determine trophic state in lakes, as shown by the statistically significant correlation between TOC and chlorophyll, total phosphorus and Secchi disk transparency. Calculation of the TSI index based on TOC according to the formula TSI(TOC) = 20.59 + 15.71 ln(TOC) and its introduction as an additional index to the classification by Carlson may optimize the comparative analysis of lakes and allow a measurable assessment of lakes with respect to the trophic gradient.

The evolution of the trophic state of the Palic Lake (Serbia)

The Palic Lake is a shallow lake typical for the Pannonian Plain. Due inadequate water quality, it was dried out in 1971 and re-established in 1977 and since than its trophicity has been worsening. Investigation of the long-term changes in the trophic state of this lake were tracked over the total phosphorous (TP), total nitrogen (TN), chlorophyll-a and Secchi disk transparency (SD transparency), expressed as the Carlson Trophic State Index (TSI). Regarding the TSI values, the water of the Palic Lake has been constantly evolving from eutrophic to hypereutrophic. TN/TP values < 10 indicate that nitrogen is the limiting factor for algal growth.