Quality Of Aquatic Ecosystems Research Articles

THE EIS OPTIONS AT MONITORING THE SPREAD OF POLLUTION IN THE STREAM

Water pollution is one of the most significant problems in the world today and is a global problem. Surface water pollution in streams and reservoirs is reflected in the deterioration of the quality of aquatic ecosystems, including those that occur in their vicinity or follow them. Lack of quality drinking water is one of the main causes of various diseases, which can lead to death, especially in developing countries. Therefore, it is important to detect water pollution in time and anticipate how it could develop and be transported in the stream. Measurements on a physical model are time-consuming and economically demanding, but for a given locality it can provide comprehensive information, including the proposal of possible measures and their verification. It is also a suitable approach for calibration and verification of mathematical models. One of the main tasks in the physical modelling of the spread of pollution in the stream was to find a suitable substance that would simulate the pollution without being aggressive towards the water pumping circuit. The method of electrical impedance spectrometry was chosen for its detection in the stream.

Spatial and seasonal variation of zooplankton assemblages in two tidal control structures in Northeastern Brazil

Zooplankton is a group of organisms that can help to understand the quality of aquatic ecosystems, as they are responsible for transforming energy matter, thus making it available to other links, making them important in aquatic trophodynamics. This study analyzed spatial and temporal variations in zooplankton communities found in two tidal control structures on Ilha do Maranhão, northeastern Brazil. Sampling took place from September 2017 to July 2018. Abiotic parameters (temperature, salinity, and transparency) and plankton samples were recorded monthly throughout the study period at each sampling site. The results found for the abiotic parameters showed a well-defined pattern, with a clear division between the dry and rainy periods. Forty taxa represented the zooplankton community of the São Luís tidal control structure, and from São José de Ribamar by 21 taxa, represented mainly by copepods, ichthyoplankton, foraminifera, polychaetes, and mollusks. The analysis of ecological indices of richness, evenness, and diversity showed a difference in the distribution of organisms among the study areas. We identified an important influence of the physicochemical parameters on the zooplankton communities of São Luís and São José de Ribamar, according to the statistical analyzes used in this study.

Inverse Margin Filtration Applied for Surface Water Treatment

Technologies to be applied under the context of protection and revitalization of surface water must be developed and improved in order to enhance the quality of aquatic ecosystems. In this way, this study aimed to evaluate the treatment performance of an inverse margin filtration system (IMF) applied in surface water treatment. The IMF was monitored during 1 year through the classic water quality parameters, and thus the treatment performance along the filtration path was identified. The results showed an average removal efficiency of 41% for turbidity, 35% for apparent color, 43% for true color, 26% for total suspended solids and total organic carbon, 53% for nitrogen, 46% for phosphorus, 91% for iron, 8% for manganese, and 100% for fecal coliforms. In this way, the IMF system proved to be a technology that can be applied in the treatment of water in lentic environments.

Quantification of metals in macrophytes in an aquaculture area of the itaipu binational reservoir

The macrophytes in natural conditions perform an important role in the maintenance and balance of aquatic environments with a capacity of absorbing the excess of nutrients and pollutants serving as bioindicators of water quality in aquatic ecosystems. The objective was to evaluate the levels of trace metals in three species of macrophytes (Egeria densa - submerged and Eichhornia crassipes and Salvinia auriculata - floating) collected around an aquaculture area of cages in the Itaipu Binational reservoir, during the four seasons of the year. The macrophyte samples were submitted of nitroperchloric digestion. Subsequently, the quantification of metals (Cu, Zn, Fe, Mn, Pb, Cd and Cr) was carried out by flame atomic absorption spectrometry analytical method. The concentration of Cu, Fe and Mn in E. densa and S. auriculata was higher (P<0.05) than in E. crassipes. The samples of S. auriculata and E. crassipes had the lowest concentrations (P<0.05) of Pb. The lowest metal pollution index (MPI) was determined in E. crassipes. There was greater bioaccumulation of metals in the root concerning the stem and leaves of E. crassipes (P<0.05). The results obtained in this study show the influence of seasonal variation in the levels of Fe and Zn and the species analyzed on the concentration of Fe, Zn and Mn accumulated in aquatic macrophytes. The macrophytes E. crassipes and E. densa can be considered efficient accumulators of metals, indicating the exposure of the concentration of trace metals around the aquaculture area intended for the fish production in cages.

Influence of tidal events on the body-size spectrum of periphytic ciliates for marine bioassessment using artificial substrata

As an internal functional trait of a community, the body-size spectrum is a highly informative indicator for bioassessment of water/environmental quality in aquatic ecosystems. To determine the influence of tidal events on body-size spectra of protozoan periphytons, a 3-month baseline survey was conducted in Korean coastal waters using the polyurethane foam enveloped slide system (PFES) and conventional slide system (CS). The body-size spectrum of the protozoans showed a clear temporal pattern during the study period using both sampling systems. However, the temporal dynamics showed significantly different trajectories in the body-size spectrum between the two sampling methods during the study period. The bootstrapped average analysis revealed that the patterns of the body-size spectrum were significantly different between the PFES and CS systems, especially in terms of frequency of occurrence. These findings suggest that the tidal events may significantly influence body-size spectrum of periphytic ciliates for bioassessment in marine ecosystems.

Diatom Communities as Bioindicators of Human Disturbances on Suburban Soil Quality in Arid Marrakesh Area (Morocco)

Diatoms, unicellular siliceous microalgae, are one of the most known groups of eukaryotic algae, commonly used as bioindicators for assessing water quality in aquatic ecosystems. Conversely, studies on terrestrial diatoms as potential bioindicators of soil quality are rather scarce. This study aims to assess the arid suburban soils quality of Marrakesh disturbed by various anthropogenic activities using diatom communities as bioindicators. The sampling of soil and physicochemical measurements were carried out at six sites with different land use. A total of 26 diatom taxa has been identified with 13 genera. The highest species richness and algal biomass were recorded in agricultural irrigated soils with treated wastewater dominated by pollution-tolerant species of Nitzschia (71.43%). In canonical correspondence analysis, suburban soils were subdivided into three groups depending on the chemical properties and diatom composition. The diatom diversity was significantly correlated with the total organic carbon (TOC), P-PO4, and N-NH4+ contents. While diversity and biomass were significantly lower in the soils affected by municipal and mining solid wastes, the input of organic matter and nutrients from treated wastewater appears to have a positive impact on the soil microflora and its richness. This first exploratory survey showed that diatom communities were more sensitive to the anthropic disturbances on urban soil and could be used as bioindicators of the quality and soils conditions.

Limnological analysis and survey of planctonic chlorophyce in the supply weir and in an effluent from the fish farming center Carlos Eduardo Matiazze in Presidente Médici, RO, Brazil

The phytoplankton consists of a diverse set of algae that are important for the water quality of aquatic ecosystems. Studies have revealed that various organisms are directly dependent on microalgae, as well as being primary producers, they are irreplaceable sources of food. Therefore, the aimed of the study was to evaluate the limnological conditions and carry out a survey of planktonic microalgae in the Chlorophyta division of the Chlorophyceae class of the supply weir and an effluent from the Carlos Eduardo Matiazze Fish Farming Center, Presidente Médici, RO, Brazil. For that, the physical-chemical parameters temperature, oxygen dissolved in water (ODA), pH, transparency, alkalinity, hardness, electrical conductivity in water (CEA), carbon dioxide and total ammonia concentration (CAT) were analyzed. The results were compared with the norms established by CONAMA Resolution 357, of 2005 fresh waters, especially class 2. And also, the survey of chlorophytes was carried out, and the analyzes of the samples were carried out by means of slide preparations for immediate reading through the observation under the binocular optical microscope. The microalgae species of the Chlorophyta division of the Chlorophyceae class were identified in a taxonomic category of order, family, genus and species. The weir water showed acceptable values, according to CONAMA, for the parameters analyzed here for most of the year. The effluent also expressed acceptable values ​​according to the legislation, with the exception of dissolved oxygen with a value of 1.7 mg/L. Concerning the survey of chlorophytes, it was observed that the weir is rich and diversified, which can be an indicator of pollutants and contamination since the weir is exposed to a large amount of effluents.

New trends in bioassessment of aquatic ecosystems: from organisms to DNA-based metrics

Traditionally, the biological quality of aquatic ecosystems is assessed using selected groups of organisms that can be identified morphologically. Recent advances in high-throughput genomic approaches offered new opportunities to monitor biodiversity and assess ecological status using DNA barcoding and metabarcoding. The DNA-based tools have been used in three different ways: (1) to replace morphological identification of biological quality elements in existing biotic indices, (2) to develop new molecular indices based on morphologically inconspicuous groups of potential environmental indicators, and (3) to predict biotic indices from environmental DNA datasets using machine learning methods (Pawlowski et al. 2018). The next steps need to take advantages and challenges of these different approaches into account in view of their future application in routine bioassessment.The Working Group 2 of DNAqua-Net, Biotic Indices & Metrics, has worked with several task forces tackling different organism groups (fish, macroinvertebrates, diatoms, bacteria, protists, meiofauna), because challenges have been shown to be quite different dependent on the target organisms Kahlert et al. 2019. For the fish the eDNA-metabarcoding methods are well developed and give very good results in terms of species detection. The important question is to see if the semi-quantitative data retrieved from the metabarcoding (proportion in eDNA sequences) could be translated to proportions in biomass/numbers that are now used in many indices. The fish researchers are trying to fit these data in, but some correction factors might be needed to correct for differences between molecular and conventional methodsRegarding the macroinvertebrates, much discussion regarding index development was focusing on the importance of abundance measurements, and it was tested how existing indices would perform if barcoding data would be used instead of morphological data. Still discussion is ongoing on several technical issues, including the use of preservative for DNA extraction from bulk samples, the choice of primers for PCR amplification and the incompleteness of reference databases which impedes the correct assignment of eDNA sequences. Also minimum standards for routine operation are still missing.The diatom group has worked much on practical issues, starting a large initiative to compare diatom metabarcoding protocols used in routine freshwater biomonitoring for standardization (Bailet et al. 2019, Keck et al. 2018, Vasselon et al. 2017). With diatoms, all three approaches to develop molecular indices have been tested and seem promising, i.e. using existing indices with taxa names derived by matching sequences with reference databases, developing new indices based on molecular data only with traditional fixed scores, and using machine-learning techniques (Bailet et al. 2020, Vasselon et al. 2018, Tapolczai et al. 2019, Keck et al. 2018) The micro- and meiobiota group has worked towards an inclusion of microorganisms into aquatic assessment, because the microbial community dynamics are a missing link important for our understanding of rapid changes in the structure and function of aquatic ecosystems, and should be addressed in the future environmental monitoring of freshwater ecosystems (Sagova-Mareckova et al. 2021). Another focus was on how sediment DNA analysis can be integrated into stated goals of routine monitoring applications. It has been an interesting journey, and we WG2 coordinators would like to thank all the people for their engagement! Keep up the good work!

Hydroacoustic Autonomous boat for Remote fish detection in LakE (HARLE), an unmanned autonomous surface vehicle to monitor fish populations in lakes

AbstractTo evaluate the aquatic ecosystem's quality and ensure the sustainable management of fisheries, it is important to monitor fish populations. Hydroacoustics uses sound waves to noninvasively scan and gather information on waterbodies including fish abundance and distribution. Unmanned surface vehicles (USV) have been increasingly used in marine and freshwater environments to enable data collection. We provide a detailed description of a new USV called Hydroacoustic Autonomous boat for Remote fish detection in LakE (HARLE), which is devoted to hydroacoustic studies in freshwater. The USV is electrically powered and equipped with the most modern fishery scientific echosounder, suitable for broadband applications, the EK80 (SIMRAD). The USV was used for a conventional hydroacoustic survey in a peri‐alpine lake to investigate its potential to monitor fish populations in lakes. In the lower layer of the lake where there were numerous targets and comparisons were possible, hydroacoustic metrics and fish biomass values (kg ha−1) from the SIMRAD EK80 on board the USV and EK60 on board the research vessel were similar. We showed that the HARLE has great potential to be used as a tool for fish monitoring and hydroacoustic survey in freshwater.

Биологические факторы качества воды в мезотрофной экосистеме

Dissolved organic matter (DOM) is one of the important parameters of water quality in aquatic ecosystems. In the experiments, phyto- and bacterioplankton actively consumed 14C-labeled chlorella hydrolyzate. Removal (by filtration) of cyanobacteria from the aquatic environment leads to an increase in the rate of DOM consumption by bacteria. This indicates the possibility of a negative effect of cyanobacterial metabolites on the physiological processes of bacterioplankton.

Estimation of Suspended Sediment Concentration from Remote Sensing and In Situ Measurement over Lake Tana, Ethiopia

Discharge from basins joining a lake is the main factor determining the lake volume and sediment inflow to the lake. Suspended sediment is an important parameter for describing the water quality of aquatic ecosystems. Lake Tana is an important and the largest lake in Ethiopia for the local ecological system. However, environmental change and anthropogenic activities in the area threaten its water quality. The conventional methods of suspended sediment concentration (SSC) observation are unable to determine and compare spatial and temporal SSC patterns for the lake over a period of years. Remote sensing methods have made it possible to map SSC. The objective of this study is to characterize the spatial and temporal distribution of suspended sediment of Lake Tana using in situ measurement and remote sensing applications and specifically to develop a relationship between in situ and remote sensing observation to retrieve suspended sediment concentration and map the spatal distribution of SSC. This study used MODIS‐Terra and in situ data to characterize the spatial and temporal distribution of SSC in the rainy season. Four sampling campaigns (20 samples per campaign) were carried out on Lake Tana, and the first three sampled campaigns on May 11–13, 2018, June 08–10, 2018, and July 15–17, 2018, were used for calibration of regression models. MODIS‐Terra reflectance in NIR was found best related to in situ water quality data and varies linearly with SSC (r2 = 0.81) and turbidity (r2 = 0.85). Secchi disc depth (SDD) found the best fit for a power relation with NIR band reflectance (r2 = 0.74). The MODIS‐Terra reflectance in red was found to be poorly related to in situ measurements. The relation in NIR reflectance was validated using the LOOCV (leave‐one‐out‐cross‐validation) technique and the fourth sampled data set collected on August 12–14, 2018. Developed models are validated with RMSE of 42.96 mg/l, 14.6 NTU, and 0.17 m, ARE of 23.3%, 27.6%, and 12.4%, and RRMSE of 25.1%, 44.5%, and 29.6% for SSC, turbidity, and SDD, respectively, using LOOCV. The equation was also validated using August 2018 collected data sets with RMSE of 87.6 mg/l, 11.7 NTU, 0.08 m, ARE of 20.8%, 25.9%, and 28.8%, and RRMSE of 17.8%, 20.5%, and 27.9% for SSC, turbidity, and SDD, respectively. Applying the developed regression model, a 10‐year time series of SSC from 2008–2017 for May‐August was estimated and the trend was tested using the Mann–Kendall trend test. It was found that an increasing trend was observed from the period 2008 to 2017. The result shows that satellite data like the MODIS‐Terra imagery could be used to monitor and obtain past records of SSC with the developed equation. The increasing SSC can be reduced by implementing selected management practices in the surrounding watersheds of the lake to reduce nutrient and sediment inflow.

Development of a Water Quality Assessment Index for the Chania River, Kenya

Human-related activities are known to have deleterious effects on the water quality of aquatic ecosystems, but there is limited information on the impact of these on rivers in tropical regions, such as the Chania River in Kenya. The Chania River is an important source of water for humans and animals and provides habitat for a variety of flora and fauna. This study used a Water Quality Index (WQI) to assess the suitability of the water for human use based on selected physico-chemical parameters (nitrates, Total Dissolved solids (TDS), potassium, sulphates, chlorides, copper, manganese, pH and phosphates). Sample collection was done between October 2018 and February 2019 over the dry and the wet seasons. Generally, the WQI indicated that water quality was fair to good in the dry season (19.67 to 30.10) but fair to poor in the wet season (23.17 to 89.15). It is recommended that the riparian zone of the Chania River be protected from anthropogenic disturbances in the County Kiambu.

Effects of organic mercury on Mytilus galloprovincialis hemocyte function and morphology

Filter-feeding organisms accumulate xenobiotics and other substances in their tissues. They can be useful as sentinel organisms in biomonitoring of the marine compartment. Bivalve cellular immunity is ensured by phagocytosis and cytotoxic reactions carried out by hemocytes in a network with humoral responses. These can be affected by chemical contaminants in water that can be immunosuppressors also at a low concentration increasing the sensibility to pathogens. This work is an attempt to individuate cellular markers for pollution detection, investigating the effect of methylmercury (CH3HgCl) at different concentrations on the activity and hemocyte morphology of the Mediterranean mussel, Mytilus galloprovincialis. We assessed the effect of three sub-lethal concentrations of the organometal on the cellular morphology, the efficacy of phagocytosis toward yeast cells, the alteration of the lysosomal membrane and the ability to release cytotoxic molecules. The results provide information on the alteration of hemocyte viability, modification of the morphological and cytoskeletal features and besides the cellular spreading, intrinsic ability of motile cells was used as a complementary investigation method. Exposure to the contaminant affected the percentage of phagocytosis and the phagocytosis index. Moreover, morphological and cytoskeleton alteration, caused by the pollutant, leads to reduced ability to incorporate the target and adhere to the substrate and the low ability of cells to retain neutral red could depend on the effects of methylmercury on membrane permeability. These results reinforce the use of the Mediterranean mussel as model for the evaluation of environmental quality in aquatic ecosystems integrating the novel information about hemocyte functions and morphology sensibility to organic mercury.Graphic abstract

Acute toxicity of heavy metal, nickel and chromium on fresh water edible fishes

Industrial effluent are the major sources of heavy metal pollution and it is released into fresh waterbodies. Catla catla and Clarias batrachus were exposed to Nickel and Chromium for 24, 48, 72 and 96 hrs. The median lethal concentration (LC50) of nickel to Catla catla and Clarias batrachus for 96 h of exposure were 5.77 mg/l and 7.595mg/l, respectively. The median lethal concentration (LC50) of chromium to Catla catla and Clarias batrachus for 96 h of exposure were 16.468 mg/l and 34.476 mg/l, respectively. The result also revealed that mortality rate depends upon concentrations of heavy metals and duration of exposure. The acute toxicity levels were derived from LC50 concentrations of the heavy metals. Both the heavy metals produced lethality at smaller doses. Physiological responses like rapid opercular movement and frequent gulping of air was observed during the initial stages of exposure after which it became occasional. All these observations can be considered to monitor the quality of aquatic eco system and severity of pollution.

Zooplankton functional traits as a tool to assess latitudinal variation in the northern-southern temperate European regions during spring and autumn seasons

Abstract Zooplankton structure may serve as predictor of a multiplicity of environmental conditions, including long-scale distance between shallow water bodies. Two different categories of zooplankton indices (1/ biocoenotic indices, including dominating species; 2/ trait-based approaches, including ecological groups: littoral vs. pelagic community and functional feeding groups) were compared in small water bodies of two regions of Europe (1/ Northern water bodies (N-WB): Poland, and 2/ Southern water bodies (S-WB): Croatia). We hypothesized that latitudinal variation between these regions will result in distinguishing specific environmental factors that in turn affect the structure of zooplankton communities. In order to avoid weather extremes in both countries, we focused our research on less frequently investigated periods of the year; during the unvegetated and mild-temperature seasons (spring and autumn). Despite well pronounced differences in some abiotic characteristics of water between both regions (higher chlorophyll a and phosphorus contents in N-WB compared to better oxygenated waters and higher water transparency in S-WB) we observed rather uniform pattern with respect to zooplankton trait-based indices in N-WB and S-WB. This may have been caused by poor habitat heterogeneity due to macrophyte absence (spring) or decaying state (autumn) and poor food supply during the spring/autumn seasons. Planktonic and detrivorous rotifers (e.g. from genera Keratella and Brachionus) predominated in both countries. Ecological and trophic functional traits were mostly determined by the morphometric and trophic properties. Irrespective of latitudinal variation, water transparency emerged as a significant factor, negatively affecting zooplankton abundance, especially the dominating detrivorous rotifers, and positively littoral zooplankton. Moreover, an increase in water area, related to higher contents of nutrients and food resources, supported a higher abundance of the majority of zooplankton feeding guilds. Our results suggested that only at the level of taxa the distinctiveness between the two European regions, northern and southern, was clear. Apart from taxa dominating in both countries (Keratella cochlearis, Bosmina longirostris), Polyarthra spp. and Eudiaptomus gracilis dominated exclusively in Croatia and Cyclops sp. in Poland during the unvegetated and temperature-transitional seasons. This indicates that only the taxonomic approach, referring to certain dominating species, was a sensitive tool. Functional trait-based approaches, despite providing relevant information on the quality of aquatic ecosystems, are not sufficiently sensitive in identification of latitudinal variation of zooplankton in the spring/autumn season.

Severe western Canadian wildfire affects water quality even at large basin scales

Wildfires can have severe and lasting impacts on the water quality of aquatic ecosystems. However, our understanding of these impacts is founded primarily from studies of small watersheds with well-connected runoff regimes. Despite the predominance of large, low-relief rivers across the fire-prone Boreal forest, it is unclear to what extent and duration wildfire-related material (e.g., ash) can be observed within these systems that typically buffer upstream disturbance signals. Following the devastating 2016 Fort McMurray wildfire in western Canada, we initiated a multi-faceted water quality monitoring program that suggested brief (hours to days) wildfire signatures could be detected in several large river systems, particularly following rainfall events greater than 10 mm. Continuous monitoring of flow and water quality showed distinct, precipitation-associated signatures of ash transport in rivers draining expansive (800–100,000 km2) and partially-burned (<1–22 percent burned) watersheds, which were not evident in nearby unburned regions. Yields of suspended sediment, nutrients (nitrogen, phosphorus) and metals (lead, others) from impacted rivers were 1.2–10 times greater than from those draining unburned regions. Post-fire suspended sediment concentrations in impacted rivers were often larger than pre-fire 95% prediction intervals based on several years of water sampling. These multiple lines of evidence indicate that low-relief landscapes can mobilize wildfire-related material to rivers similarly, though less-intensively and over shorter durations, than headwater regions. We propose that uneven mixing of heavily-impacted tributaries with high-order rivers may partially explain detection of wildfire signals in these large systems that may impact downstream water users.

Metabolic enzyme profile, behavioural changes and morphophysiological parameters of African catfish Clarias gariepinus juveniles in response to burnt waste tyres

Water-soluble fractions (WSFs) of waste burnt tyres (WBTs) were tested on enzymatic activities, behavioural changes and histology of gills and liver of African catfish Clarias gariepinus juveniles for 96 h at 5.00, 10.00, 15.00, 20.00 and 25.00 g/L in a non renewable static bioassay. Water quality parameters of the experimental media showed significant (p < 0.05) decrease in pH and dissolved oxygen content and increased carbon dioxide and alkalinity levels compared to the control. The 96-h LC50 of WSFs of WBTs to C. gariepinus was calculated as 11.22 g/L. There were remarkable abnormal behaviours exhibited by the exposed fish as well as alteration in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and lactate dehydrogenase activities in gills and liver in a dose-dependent manner. The exposure also led to changes in primary and secondary gill lamellar hypertrophy and hyperplasia, partial fusion of apical lamellar, cytoplasmic and nuclear degeneration of parenchyma cells, as well as cytoplasmic vacoulation, sinusoidal oedema and nuclear and periportal hepatocyte degeneration of the liver. Hepatomorphometry of the fish revealed significant (p < 0.05) increase in nuclear surface area as well as nuclear diameter of the hepatic cells. BWTs could be deleterious to aquatic biota including fish and could be adopted as biomarkers for assessing the quality of aquatic ecosystem.

Secchi Disk Depth Estimation from China’s New Generation of GF-5 Hyperspectral Observations Using a Semi-Analytical Scheme

Water clarity, commonly measured as the Secchi disk depth ( Z s d ), is an important parameter that depicts water quality in aquatic ecosystems. China’s new generation Advanced HyperSpectral Imager (AHSI) on board the GF-5 satellite has significant potential for applications of more accurate water clarity estimation compared with existing multispectral satellite imagery, considering its high spectral resolution with a 30-m spatial resolution. In this study, we validate the semi-analytical model with various Quasi-Analytical Algorithms (QAA), including Q A A V 5 , Q A A V 6 , Q A A L 09 and Q A A M 14 , for the AHSI images with concurrent in situ measurements in four inland water bodies with a Z s d range of 0.3–4.5 m. The semi-analytical method with Q A A V 5 can yield the most accurate Z s d predictions with approximated atmospheric-corrected remote sensing reflectance. For 84 concurrent sampling sites, the estimated Z s d had a mean absolute error (MAE) of 0.35 m, while the mean relative error (MRE) was 25.3%. Specifically, the MAEs of estimated Z s d were 0.22, 0.46, and 0.24 m for Z s d of 0.3–1, 1–3, and 3–4.5 m, respectively. The corresponding MREs were 33.1%, 29.1% and 6.3%, respectively. Although further validation is still required, especially in terms of highly turbid waters, this study indicates that AHSI is effective for water clarity monitoring.

Mapping of Sea Surface Temperature and its Correlation with Salinity Concentration in The Coastal Beach of Bangkalan Madura District

Sea surface temperature is one of the parameters that plays a role in the quality of aquatic ecosystems in the sea, especially in shallow marine waters. Other parameters that play a role in determining the quality of the soil on the coast are salinity concentrations, which defines the mineral content of salts that are in the structure of soil widely used for farming or for ponds. This study aims to obtain a correlation of salinity to changes in temporal sea surface temperature for 2 consecutive years on the coastal areas of Bangkalan Madura district as a case study. The method used in this study was mapping with remote sensing using Terra Modis satellite imagery for 2018 and 2019. The acquisition of SST data used the ATBD algorithm and field data while for salinity field data were used. The study found that the magnitude of the SST values during the temporal analysis was not too much different in 2018 and 2019, only for correlations with salinity, the statistically calculated error rate of 5% showed that there were sufficient differences with the SST changes that occured during a year. The conclusion is that there was a significant correlation of the amount of salinity concentration with changes in sea surface temperature that occurred during the year of observation and this requires serious handling so that high salinity in coastal areas do not seep into the land which would have a negative impact on coastal communities.

Response of traditional and taxonomic distinctness diversity indices of benthic macroinvertebrates to environmental degradation gradient in a large Chinese shallow lake.

A variety of biodiversity metrics are available to assess the quality of aquatic ecosystems. However, different types of metrics perform with considerable variation and provide various information involved in ecosystem conditions. Taxonomic distinctness (TD) indices have been recommended as desirable measures for assessing environmental degradation, but their utility based on lake macroinvertebrates is still largely unknown. Here, we evaluated the response of traditional and taxonomic distinctness diversity indices (the average taxonomic distinctness, Δ+, and variation in taxonomic distinctness, Λ+) of benthic macroinvertebrates to environmental degradation gradient in Lake Taihu, the third largest freshwater lake in China. Benthic assemblages responded markedly to human disturbances, with significance among-region differences in community composition throughout four seasons. The traditional biodiversity indices (Shannon-Wiener diversity and Pielou's evenness) showed high sensitivity in discriminating anthropogenic impacts, with highest values in macrophytic region but lowest values in eutrophic region. In contrast, Δ+ and Λ+ did not perform well in distinguishing sites subjected to different disturbance levels. The Pearson correlation and multiple regression analysis both indicated that traditional biodiversity metrics (Shannon-Wiener diversity, taxon richness, and Pielou's evenness) responded more readily to water quality variables (Secchi depth, electrical conductivity, and comprehensive trophic level index) than Δ+ and Λ+. Despite the weak correlations between TD indices of benthic macroinvertebrates and water quality in the present study, we suggest that the TD indices should still be considered in bioassessment programs because they provide useful complementary information on traditional diversity indices.