Phytoplankton Species Diversity Research Articles

Investigating the differences in driving mechanisms for phytoplankton community composition under various human disturbances in cold regions

In river ecosystems, phytoplankton are essential components, and this study delves into their response to critical environmental indicators. We analyzed the spatiotemporal variations of phytoplankton diversity in cold regions, employing techniques such as Principal Component Analysis (PCA), Spearman correlation coefficient, and Generalized Additive Model (GAM) to unveil the critical environmental factors influencing phytoplankton diversity and habitat suitability under varying degrees of human interference. With 37 monitoring stations across two cold region rivers, phytoplankton and water bodies were monitored in spring, summer, and autumn, resulting in the collection and analysis of 111 phytoplankton samples and 13 environmental indicators at each station. By identifying critical water quality indicators and exploring nonlinear relationships, the study revealed intricate interactions between phytoplankton diversity and environmental factors. Our findings suggest that overall phytoplankton species diversity is lower in rivers with high human interference, with turbidity, NH4+-N, chlorophyll-a, and total phosphorus (TP) deemed critical factors. Conversely, chlorophyll-a, NH4+-N, and electrical conductivity (EC) were identified as important factors in rivers with lower human interference, indicating differences in phytoplankton driving mechanisms between the two rivers. These insights provide valuable references for the sustainable development and effective assessment of cold region river ecosystems in the Anthropocene.

Integrated machine learning reveals aquatic biological integrity patterns in semi-arid watersheds

Semi-arid regions present unique challenges for maintaining aquatic biological integrity due to their complex evolutionary mechanisms. Uncovering the spatial patterns of aquatic biological integrity in these areas is a challenging research task, especially under the compound environmental stress. Our goal is to address this issue with a scientifically rigorous approach. This study aims to explore the spatial analysis and diagnosis method of aquatic biological based on the combination of machine learning and statistical analysis, so as to reveal the spatial differentiation patterns and causes of changes of aquatic biological integrity in semi-arid regions. To this end, we have introduced an innovative approach that combines XGBoost-SHAP and Fuzzy C-means clustering (FCM), we successfully identified and diagnosed the spatial variations of aquatic biological integrity in the Wei River Basin (WRB). The study reveals significant spatial variations in species number, diversity, and aquatic biological integrity of phytoplankton, serving as a testament to the multifaceted responses of biological communities under the intricate tapestry of environmental gradients. Delving into the depths of the XGBoost-SHAP algorithm, we discerned that Annual average Temperature (AT) stands as the pivotal driver steering the spatial divergence of the Phytoplankton Integrity Index (P-IBI), casting a positive influence on P-IBI when AT is below 11.8 °C. The intricate interactions between hydrological variables (VF and RW) and AT, as well as between water quality parameters (WT, NO3–N, TP, COD) and AT, collectively sculpt the spatial distribution of P-IBI. The fusion of XGBoost-SHAP with FCM unveils pronounced north-south gradient disparities in aquatic biological integrity across the watershed, segmenting the region into four distinct zones. This establishes scientific boundary conditions for the conservation strategies and management practices of aquatic ecosystems in the region, and its flexibility is applicable to the analysis of spatial heterogeneity in other complex environmental contexts.

Phytoplankton Diversity as a Bioindicator for Water Quality of Pertamina Harbour Ampenan, Lombok

Ampenan district is an area that has a fairly high population density. There are community activities such as selling on the beach, littering, tourism activities and crossing activities at the Pertamina Harbour Ampenan which can cause a decrease in water quality. This research was conducted to determine water quality of Pertamina Harbour Ampenan based on phytoplankton community. Sea waters samplings were carried out using a 20µm plankton net. Observation and identification of phytoplankton was carried out in advances biology laboratory, FMIPA, Mataram University using a binocular microscope. Phytoplankton data were analyzed based on the abundance, diversity, dominance and saprobity index. The results of this research showed that the phytoplankton community of the Pertamina Harbour Ampenan waters consisted of 106 species from 6 classes with an abundance value of 4324,455 ind/L. Spesies diversity and dominant indexs of phytoplankton, and saprobic indexes of the Pertamina Harbour Ampenan waters were 1,767, 0,451 and 2,56 respectively. Based on the phytoplankton species diversity index, the waters of Pertamina Harbour Ampenan was categorized as moderately polluted, whereas saprobity index the waters of Pertamina Harbour was categorized as oligosaprobic.

Phytoplankton ecology in the early years of a boreal oil sands end pit lake

BackgroundBase Mine Lake (BML) is the first full-scale end pit lake for the oil sands mining industry in Canada. BML sequesters oil sands tailings under a freshwater cap and is intended to develop into a functional ecosystem that can be integrated into the local watershed. The first stage of successful reclamation requires the development of a phytoplankton community supporting a typical boreal lake food web. To assess the diversity and dynamics of the phytoplankton community in BML at this reclamation stage and to set a baseline for future monitoring, we examined the phytoplankton community in BML from 2016 through 2021 using molecular methods (targeting the 23S, 18S, and 16S rRNA genes) and microscopic methods. Nearby water bodies were used as controls for a freshwater environment and an active tailings pond.ResultsThe phytoplankton community was made up of diverse bacteria and eukaryotes typical of a boreal lake. Microscopy and molecular data both identified a phytoplankton community comparable at the phylum level to that of natural boreal lakes, dominated by Chlorophyta, Cryptophyta, and Cyanophyta, with some Bacillariophyta, Ochrophyta, and Euglenophyta. Although many of the same genera were prominent in both BML and the control freshwater reservoir, there were differences at the species or ASV level. Total diversity in BML was also consistently lower than the control freshwater site, but consistently higher than the control tailings pond. The phytoplankton community composition in BML changed over the 5-year study period. Some taxa present in 2016–2019 (e.g., Choricystis) were no longer detected in 2021, while some dinophytes and haptophytes became detectable in small quantities starting in 2019–2021. Different quantification methods (qPCR analysis of 23S rRNA genes, and microscopic estimates of populations and total biomass) did not show a consistent directional trend in total phytoplankton over the 5-year study, nor was there any consistent increase in phytoplankton species diversity. The 5-year period was likely an insufficient time frame for detecting community trends, as phytoplankton communities are highly variable at the genus and species level.ConclusionsBML supports a phytoplankton community composition somewhat unique from control sites (active tailings and freshwater lake) and is still changing over time. However, the most abundant genera are typical of natural boreal lakes and have the potential to support a complex aquatic food web, with many of its identified major phytoplankton constituents known to be primary producers in boreal lake environments.

Phytoplankton community structure during the melting phase of the land-fast ice in Prydz Bay, east Antarctica

Phytoplankton, the primary producers of all aquatic systems, form the base of the marine food web. Any change in the environmental settings of the given ecosystem will affect the phytoplankton community structure of the region. In the present work, water sampling was carried out from the poorly explored polar region, beneath the sea ice during the melting phase of land-fast ice near Indian Antarctic Research Station Bharati in Prydz Bay, East Antarctica. The water samples were analyzed for phytoplankton species diversity, nutrients, temperature, salinity, and Chlorophyll a (Chl a). Our observations indicate marked variations in phytoplankton biomass and community. A shift from diatom (Thalassiosira sp., Fragilariopsis sp.) to dinoflagellate (Protoperidinium sp.) community, along with the emergence of grazers was seen by the end of the observation period. The background environmental conditions also showed marked variations, as the concentration of nitrate at 0m depth reduced from 31.8 μM at Obs-1 to a non-detectable limit at Obs-3. Furthermore, at 0m depth, temperature increased from −1.32 °C at Obs-1 to −0.38 °C at Obs-3 while salinity decreased from 34.11 at Obs-1 to 33.68 at Obs-3, thus indicating the melting phase of sea ice from Obs-1 to Obs-3. These observations showed vertical stratification resulting from the basal melting of land-fast sea ice resulted in better availability of light, phytoplankton community change due to nutrient availability/utilization/limitation, followed by the presence of grazer community. This preliminary understanding will serve as a baseline dataset to design the targeted sampling/experiments in the future from the land-fast ice ecosystem.

Thermocline stratification favors phytoplankton spatial overlap and species diversity in a subtropical deep reservoir

Spatial segregation of species along opposing resource gradients is a major research topic in ecology as it enables the coexistence and maintenance of high diversity. Thermocline stratification causes heterogeneous resource distribution, however, the effect of thermocline stratification on phytoplankton dynamic in-depth profiles is still unclear. To understand the underlying mechanism behind the effects of thermocline stratification on phytoplankton species diversity in stratified lakes, the monthly changes in thermocline parameters, deep chlorophyll maxima (DCM) parameters, spatial overlap (SO) among major phytoplankton taxonomic groups, and phytoplankton species diversity were evaluated in Lake Qiandaohu in the Zhejiang Province of China from April 2017 to December 2018. Thermocline depth (TD) was significantly negatively related to thermocline strength (TS). The monthly air temperature was the main driver behind the thermocline and the seasonal thermal-stratification cycle was divided into two stratification stages. Significant linear relationships were observed between the DCM parameters (depth, concentration, and thickness) and TD during the strong stratification period. TD was significantly positively related to phytoplankton species diversity and the SO between Cryptophyta and Chlorophyta as well as between Cryptophyta and Bacillariophyta during weak stratification periods. Significant positive correlations were observed between SO and Shannon diversity during both periods. Structural equation modeling (SEM) showed that air temperature significantly decreased TD and increased species diversity by increasing SO during the strong stratification period. Strong stratification under warming favored the formation of shallower and thinner DCMs, leading to phytoplankton coexistence and maintenance of high species diversity through a preclusion of dominance. This study characterized the temporal dynamics of phytoplankton dynamic in-depth profiles in response to strong stratification from warming.

Predictable shifts in diversity and ecosystem function in phytoplankton and zooplankton communities along thermocline stratification intensity continua

Thermocline stratification is a global threat to water quality in drinking water reservoirs, though its underlying mechanisms are not clear. The impacts of thermocline stratification intensity on biodiversity-ecosystem relationships were assessed using phytoplankton and zooplankton indicators from four stages of stratification in Lake Qiandaohu. There were significant differences in biomass, species diversity, and resource use efficiency (RUEpp = phytoplankton biomass/total phosphorus) for phytoplankton between continuous stratification and mixing periods, but only in FDis and RaoQ diversity indices for zooplankton. Phytoplankton species diversity and RUE were higher in the formative and stable periods, while zooplankton species diversity and zooplankton biomass/phytoplankton biomass (RUEzp) were lower. When combining the data from the four periods, a negative linear pattern was found between phytoplankton Simpson's, functional dispersion (FDis), and Rao's Quadratic (RaoQ) diversity indices, and thermocline depth (TD). Only zooplankton FDis and RaoQ diversity indices were significantly positively related to TD. Phytoplankton RUE was significantly negatively related only to its Pielou's evenness (J) diversity, while zooplankton RUE was significantly negatively related to its J, FDis, and RaoQ diversity indices. The results of structural equation models (SEMs) showed that the R2 of RUE for phytoplankton was much higher than that for zooplankton. Thermocline stratification intensity exerted an indirect positive effect on phytoplankton RUE by affecting species diversity but had a negative effect on zooplankton RUE. These findings underscore the negative influence of thermocline stratification resulting in various biodiversity changes in freshwater ecosystems.

Features of the distribution of hydrological, chemical and biological characteristics in the waters of the Central-East Atlantic in the autumn of 2022 (cruise 63 of the R/V «Akademik Ioffe»)

The goal of the work: to determine the water structure in the Central part of East Atlantic and to identify the features of the distribution of hydrological, chemical and biological characteristics of the upper layer in the autumn periodMaterials and methods: the data presented in the work were obtained on the 63rd cruise of the R/V «Akademik Ioffe» (September 29, 2022–December 8, 2022). During the expedition, hydrological and chemical (temperature, salinity, pH, dissolved oxygen, phosphates, nitrites, nitrates and silicates) characteristics were measured from the surface to the bottom, as well as biological (number, biomass and species diversity of phytoplankton), taken with chemical samples on depths of 0, 10, 20 and 50 m. Chemical analysis was carried out in the ship’s laboratory, according to certified methods for sea and fresh waters. Phytoplankton samples were thickenedusing a reverse filtration funnel through track (nuclear) membranes and fixed with Lugol’s solution to a final concentration of 5%. To study the species diversity, abundance and biomass of plankton microalgae, samples were processed by direct microscopy of algae in a living and thickened drop (V = 0.01 ml), as well as in a counting chamber (V = 0.5 ml) using an Olympus CX43 light microscope (magnification 10×20, 10×40). Identification of taxonomic groups and species composition of microalgae, calculations of the abundance and biomass of phytoplankton, as well as the Sörensen-Czekanowski floristic similarity coefficient according to the adoption of the methods of the « IBSS RAS» were carried out.The practical significance of the research: assessment of the production stock in a poorly studied region of the Central Eastern Caucasus, identification of mechanisms for influencing production processes, assessment of the variability of the water structure against the background of climate change.

Phytoplankton diversity as a bioindicator for water quality of siwak bay, Specific Economic Zone (SEZ) Mandalika Central Lombok

The Mandalika Specific Economic Zone (SEZ) is a potential tourism industry for the province of West Nusa Tenggara, which has recently received very high attention due to the construction of the international MotoGP circuit. The construction of the MotoGP circuit has become an attraction for domestic and foreign tourists and has increased the number of tourists. The increase in tourism activity has negatively impacted the Mandalika SEZ's coastal waters, such as a decrease in water quality, including the water of Siwak Bay. Water quality monitoring can be done by using phytoplankton as a bioindicator. The study of phytoplankton species diversity as a bioindicator of water quality has never been carried out in the Siwak Bay waters. This research was conducted to analyze the status of Siwak Bay waters based on the phytoplankton diversity index. Samplings were carried out based on a purposive sampling method. This research was conducted for three months, from March to June 2023. The study found seven classes, 59 genera, and 127 phytoplankton species. The abundance of phytoplankton in Siwak Bay was 1025,185 ind/L. The highest abundance was the genus of Trichodesmium. The species diversity index was 3,33. Based on the species diversity index, it can be said that the waters of Siwak Bay are not polluted.

Phytoplankton as Bioindikator of Water Quality in The Batu Dendeng River West Lombok

This exploratory descriptive study with a qualitative approach was aims to analyze the water quality of the Batu Dendeng River in West Lombok through a study of the phytoplankton community structure. Sampling was carried out using purposive sampling method. Water sampling was carried out using plankton net of 20µ mesh sized. Observation and identification of phytoplankton was carried out at the Biology Laboratory of FKIP University of Mataram using a binocular microscope. Phytoplankton data was analyzed based on abundance, species diversity, species uniformity and species dominance indexs. The results showed that the community structure of identified phytoplankton in the Batu Dendeng River consisted of 5 classes and 52 species with abundance value of 714.074 (ind/L). Phytoplankton species diversity, uniformity, and dominance indexs of Batu Dendeng River were 2.591, 0.66, and 0.13 respectively. The water pollution criteria based on the diversity index of phytoplankton species, indicates the water quality of the Batu Dendeng River West Lombok was in the slightly polluted category.

A fjord with a land-terminating glacier: Meltwater, bio-optics, particulate matter, nutrients, phytoplankton species, and primary production in west Greenland

Land-terminating glaciers and submarine melting of marine-terminating glaciers are significant features in Arctic regions and are foreseen to become more frequent as marine-terminating glaciers ultimately develop into a land-terminated state. A transition driven by the continuous rise in Arctic air temperatures, and emphasizes the importance of studies of land-terminating glaciers their bio-optical properties and biogeochemistry. Kangerlussuaq in west Greenland with a land-terminating glaciers and was selected for this study. During a research cruise we measured spectral and PAR attenuation, particulate matter concentrations, salinity, nutrient concentrations, Chla, and phytoplankton species composition, along a transect from river outlet to open marine waters. Results showed that surface waters in Kangerlussuaq were strongly influenced by meltwater with low salinities, high particulate matter concentrations, high PAR and spectral light attenuation coefficients, and low nutrient concentrations. Spectral composition was also affected by the particulate matter. PAR photic depths varied between 4 and 9 m dependent on particulate matter concentrations. There was a decrease with distance from outlet in silicate concentrations, and opposite for phosphate, which increased significantly from river outlet to the marine. Phytoplankton species number (42) and diversity were high at the marine station but low (3) in turbid waters dominated by the diatom Skeletonema costatum in high numbers. A meltwater plume covered about 50 % of the Kangerlussuaq at average discharges in early August. Primary production was quantified with a simple model based on light attenuation coefficients, and showed a near exponential decrease in production with increase in attenuation.

Impact of agricultural practices on ecosystem health of lagoons: a case study of the Keta Lagoon Complex in Ghana, West Africa

The paper reports on the current ecological health of the Keta Lagoon Complex by analyzing a suite of physical, chemical, and biological environmental conditions prevailing within it. Results are discussed in relation to the main human activity (i.e., agriculture) prevailing in its catchment. The current water quality of the lagoon has declined compared to data collected 20years ago with elevated levels in parameters such as nitrate, phosphate, turbidity, and temperature. Secchi disk depth, salinity, and dissolved oxygen levels in the lagoon have decreased. More than 60% of the total area of the lagoon is predicted to be currently unsuitable to support aquatic life. The Carlson's TSI estimated for the various zones of the lagoon ranged between 72.40 and 80.61 depicting a highly eutrophic lagoon, with about 90% of the total area studied confirmed to be experiencing some degree of eutrophication. The plankton index of biotic integrity also yielded high values of between 3 and 6 in most areas of the lagoon, thereby affirming the poor health of the lagoon. The diversity of phytoplankton and benthic macroinvertebrate species in the lagoon has reduced significantly in the last two decades with about 11 genera of phytoplankton missing in the present study. Benthic macroinvertebrate assemblage richness, evenness, and diversity have decreased from 3.6, 2.0, and 5.8 in 2008 to 1.2, 0.8, and 1.7 respectively, in the present study. Overall, the health of the Keta Lagoon remains poorer and continues to decline with no signs of recovery.

Spatio-temporal variation in phytoplankton community structure in backwaters of the Ketar River, central Ethiopia

This study assessed the spatio-temporal dynamics of the phytoplankton community in backwaters of the Ketar River, central Ethiopia, in relation to water quality and macrophyte coverage. Phytoplankton samples and physicochemical information were collected at six sites along the river over 1 year (December 2017 to November 2018). Phytoplankton was collected using a 15-μm mesh net. A total of 56 species belonging to three algal phyla were identified; the most diverse phylum was Bacillariophyta (35 species), followed by Chlorophyta (13 species) and Euglenophyta (eight species). Bacillariophyta had the highest abundance and contributed 80.08% of the total phytoplankton abundance. Site 6 in the downstream portion had the highest abundance and greatest diversity of phytoplankton species. The algal phyla present showed significant differences in species diversity and abundance both spatially and temporally. Redundancy analysis results revealed that the spatial distribution of phytoplankton in the river positively correlated with pH, electrical conductivity, dissolved oxygen and nitrate-nitrogen, while water temperature and total suspended solids correlated negatively. Some indicators of organic pollution suggest that the water quality of the river is progressively declining, meriting close monitoring.

Diversity and Distribution of Harmful Algal Bloom Species from Seamount to Coastal Waters in the South China Sea.

Mount Xianbei is one of the largest shallow seamounts located in the middle of the South China Sea (SCS), which might play a role in shaping the biodiversity of surrounding continental coastal waters, particularly the diversity of phytoplankton species causing frequent harmful algal blooms (HABs) in northern SCS. However, the diversity, composition, and distribution of phytoplankton species in the seamount regions of Xianbei remain largely unexplored. In this study, samples around and outside the seamount regions were collected during a late summer cruise of 2021 to test whether seamounts play a role in HAB species propagation. In total, we identified 19 HAB species across all samples using the ASV-based DNA metabarcoding approach, 6 of which had not been reported previously in the SCS, suggesting a diverse HAB species in the SCS. Specifically, 16 HAB species were found in the seamount region of Xianbei, and 5 of them were also found in the coastal waters, indicating a close connection between seamount and coastal waters. This study was the first attempt to explore HAB species' spatial diversity and vertical distribution in the seamount region of Xianbei at single-nucleotide resolution, which provides a novel explanation for the coastal HAB occurrence in the northern SCS. IMPORTANCE There are a number of seamounts under the water of the South China Sea (SCS). The seamounts might play a role in shaping the biodiversity of surrounding continental coastal waters. However, there is no direct evidence revealing the relationship of the biodiversity of phytoplankton between seamounts and coastal waters in the SCS, especially those species having the potential to form harmful algal blooms (HABs). Some HAB species might proliferate in certain geographic locations, while others may be broadly distributed across oceanic provinces. In this study, we provided a detailed analysis of phytoplankton composition and molecular detection of HAB species from seamount to coastal waters in the SCS, which suggested a strong interaction in the HAB species between the two areas. This finding provides new insights into the diversity and distribution of HABs in seamounts and their role in shaping the composition and the occurrence of HABs in coastal water.

Advances in phytoplankton population ecology in the Pearl river estuary

Phytoplankton is an important primary producer of the estuarine ecosystem, which is essential for the biogeochemical cycle of water elements and nutrient transfer. The Pearl River estuary (PRE) is a dynamically complex estuary, and the environment of PRE is significantly impacted by anthropogenic activities, variation of phytoplankton community structure in the PRE are complex. This review aims to compare phytoplankton species, species diversity, and abundance variation characteristics from the 1980s and 2020s, evaluate the overall trend of phytoplankton in the PRE, and discuss the main environmental factors affecting phytoplankton growth in the PRE. The data from the past 40 years in PRE showed that the number of phytoplankton species significantly decreased (p < 0.05). There was no significant difference in the abundance of phytoplankton at the 10-year scale, however, the fluctuation range of the abundance has increased. Under the conditions of a decreasing species number and no significant difference in abundance, the species diversity of phytoplankton showed a downward trend. In addition, the dominant phytoplankton species in the nearshore waters were relatively homogenous, and the abundance of phytoplankton in the nearshore waters was higher than that in the open waters, which suggested that human activities have a great influence. This review can form the basis for facilitating health management in the PRE ecosystem. Further, relevant guidelines can be developed and implemented for promoting the ecological health of the Guangdong-Hong Kong-Macao Greater Bay Area and ensuring its sustainable development.

Study of Phytoplankton Abundance and Species Diversity in Shahjangi Pond of Bhaghalpur District, Bihar, India

In the present study, species diversity and phytoplankton abundance were examined in Shahjangi Pond in the Bhagalpur region of Bihar. The present study was carried out from April 2021 to March 2022. Phytoplankton is considered a type of microscopic plankton capability of a photosynthesis process that is found as an essential element of the aquatic ecosystem. Phytoplankton can range in size and shape and they are photosynthesizing autotrophic organism The primary goal of this study is to learn more about the variety of phytoplankton in this pond. A blotting silk net was used to capture the sample. The planktons were collected in wide, thick bottles with a 200ml capacity. The vial containing the filtrate was then brought to the lab. In the laboratory 5ml of 4%, formalin solution was added collected filtrate. Under a compound microscope, sample analysis was carried out at 10x and 40x magnification.

Species diversity and community structure of phytoplankton in the Velikaya Salma Strait (Kandalaksha Bay, White Sea) in 2021

The species diversity and community structure of phytoplankton in the Velikaya Salma Strait (Kandalaksha Bay, the White Sea) were investigated from May to September 2021. A total of 128 algal taxa were identified, comprised of diatoms (80% of the total phytoplankton species number), dinophytes (15%), cyanobacteria (3%), ochrophytes (1%) and cercozoans (1%). The phytoplankton abundance varied from 1.84х106 cells/m3 (in August) to 23.27х106 cells/m3 (in July); phytoplankton biomass varied from 31.4 mg/m3 (in May) to 246.7 mg /m3 (in July). Diatoms was the dominant group in terms of quantity and biomass, one dinophyte species, Sсrippsiella acuminata, was dominant in terms of quantity too.

State of marine biota in the water area of the Muchke Bay’s Coal Terminal of the Tatar Strait

An analysis of the species composition of phytoplankton and ichthyoplankton was carried out for the first time in the port water area of the Muchke Bay (Tatar Strait) in autumn. The species composition, distribution features and structure of macrozoobenthos were considered. Phytoplankton density is evenly distributed in the study area. The density of diatoms reached 97 % of the total phytoplankton density, and the biomass was 99 %. The microalgae Sceletonema costatum (Greville) Cleve, 1873 and Cylindrotheca closterium (Ehrenberg) Reimann & J.C.Lewin, 1964, species that live in polluted waters, were discovered. The development of phytoplankton in the autumn period was active, but the peak of flowering was not observed. Ichthyoplankton in October 2017 is represented by live eggs of Limanda sakhalinensis (Schmidt, 1904) (8 ind./m3), in September 2018 - by the larvae of Hexagrammos stelleri Tilesius, 1810 (0.003-0.056 ind./m3) and H. octogrammus (Pallas, 1814) (0.01-0.077 ind./m3). Up to 85 representatives of macrozoobenthos were registered from the research area, including 40 species of Polychaeta, 19 ones of Crustacea, 16 species of Mollusca, 5 ones of Echinodermata and 5 species of other fauna groups. After dredging, a decrease in the species diversity of phytoplankton, ichthyoplankton and macrozoobenthos was found in the samples.

Seasonal Species Diversity and Dominance of Phytoplankton in Different types of tropical Domestic Sewage Oxidation Ponds

Planktons are small microscopic organisms, comprising diatoms and algae, which form the basis of primary production and the zooplankton, which are mainly crustaceans, rotifers and larval stages of larger animals. Both are the bio-indicators of a water body, constituting the main food for the carnivorous and omnivorous fishes in any aquatic ecosystem. In the present study, the species diversity, and their abundance with a total and average population of various species of phytoplankton have been studied in the primary and secondary domestic oxidation ponds along with a freshwater control pond situated at Shahpura. Bhopal, Madhya Pradesh, India. Physicochemical parameters like light penetration, water temperature, pH and DO were also analyzed along with the phytoplankton population in both types of ponds to assess their impacts. The samples were collected and identified using standard methods. The results revealed that the phytoplankton groups like Chlorophyceae, Bacillariophyceae, Cyanophyceae and Euglenophyceae were dominantly found in the sewage oxidation ponds along with about 20 species of phytoplankton in varying population densities in different seasons. A similar analysis was done in a freshwater control normal pond for comparison. Physicochemical parameters in these secondary sewage oxidation ponds with a high nutrient load were found to be highly favourable for the growth of the plankton species. A comparatively low number of phytoplankton was recorded in the freshwater control pond, which was highly deficient in nutrients.

AI facilitated fluoro-electrochemical phytoplankton classification.

Marine phytoplankton is extremely diverse. Counting and characterising phytoplankton is essential for understanding climate change and ocean health not least since phytoplankton extensively biomineralize carbon dioxide whilst generating 50% of the planet's oxygen. We report the use of fluoro-electrochemical microscopy to distinguish different taxonomies of phytoplankton by the quenching of their chlorophyll-a fluorescence using chemical species oxidatively electrogenerated in situ in seawater. The rate of chlorophyll-a quenching of each cell is characteristic of the species-specific structural composition and cellular content. But with increasing diversity and extent of phytoplankton species under study, human interpretation and distinction of the resulting fluorescence transients becomes increasingly and prohibitively difficult. Thus, we further report a neural network to analyse these fluorescence transients, with an accuracy >95% classifying 29 phytoplankton strains to their taxonomic orders. This method transcends the state-of-the-art. The success of the fluoro-electrochemical microscopy combined with AI provides a novel, flexible and highly granular solution to phytoplankton classification and is adaptable for autonomous ocean monitoring.