Phytoplankton Functional Groups Research Articles

Ecological assessment of Burç Reservoir’s surface water (Turkey) using phytoplankton metrics and multivariate approach

The present study aimed to elucidate relationships between phytoplankton species and stressors using multivariate approaches and assess the environmental condition of Burç Reservoir?s surface water using phytoplankton metrics from September 2018 to August 2019 according to implementations of the Water Framework Directive. Burç Reservoir had a characteristic of a warm monomictic pattern. Phytoplankton functional groups (E, F, J, LO, LM, MP , P, S1 , T, and W1 ) were found in the reservoir. A significant difference was found in total biovolume values changed from 2.28 mm3 /L in November 2018 to 0.51 mm3 /L in February 2019. The first two axes of canonical correspondence analysis explained 99.2% of relationships between stressors and phytoplankton assemblages. Explanatory factors such as electrical conductivity (EC), nitrate (NO3 -N), total nitrogen (TN), water temperature, calcium (Ca+2), precipitation, total organic carbon (TOC), ortho-phosphate (o-PO4 ), and total phosphorus (TP) significantly drove the spatiotemporal distribution of phytoplankton. Weighted average regression resulted that phytoplankton species such as Gymnodinium saginatum, Snowella lacustris, Ceratium hirundinella, and Pseudanabaena limnetica were closely associated with high TP, while Fragilaria capucina, Navicula trivialis, Cymbella aspera, Ulnaria biceps, Nitzschia palea, and Pseudopediastrum boryanum closely related to the EC. Carlson's trophic state index indicated that Burç Reservoir mainly has a eutrophic characteristic with the assessment of chlorophyll a, total phosphorus, and Secchi disk depth, while it had a eu-hypertrophic according to the OECD classification. Results of the modified PTI-phytoplankton trophic index (mean = 2.37), the Med-PTI Mediterranean phytoplankton trophic index (mean = 1.96), and the Q assemblage index (mean = 2.58) indicated a moderate ecological status of Burç Reservoir. The present study confirmed that phytoplankton assemblages are closely integrated with the environmental condition of Burç Reservoir, which could be assessed by using the PTI and Med-PTI.

Assessing ecological status in karstic lakes through the integration of phytoplankton functional groups, morphological approach and environmental DNA metabarcoding

Phytoplankton is one of the key Biological Quality Elements within the Water Framework Directive, used to assess the ecological status of surface water bodies. Water samples for phytoplankton identification were collected from April to September at a total of eight sampling sites in all six Croatian natural karstic lakes with an area greater than 0.5 km2. The main objective was to show the comparability of environmental DNA metabarcoding (Illumina sequencing using the hypervariable V9 region of the eukaryotic SSU rRNA gene) with morphologically based assessment and its applicability in assessing the ecological status of lakes. The value of Hungarian lake phytoplankton index (HLPI) indicating the final ecological status was calculated for both datasets using biomass and composition metrics. Chlorophyll a concentration measured using Ultra-High-Performance Liquid Chromatography and Spectrophotometer giving two biomass metrics along with the functional group approach (FG) as the composition metric for the complete taxa/operational taxonomic units (OTUs) lists as well as for the taxa/OTUs that contributed more than 5% to the total biomass/number of amplicons gave four to four HLPI values per sample. HLPI values from both approaches were highly correlated (Pearson's r > 0.92) and classified into good or high ecological status, although different compositions and proportions of FGs were recorded, thus giving the important role to the equal or similar factors assignment to different FGs with similar ecological demands and favourable habitats. In 89% of the samples, HLPI values indicate an equal range of ecological status and most differences were found due to different methods of Chlorophyll a measurement. Different composition metrics between approaches showed significant differences (p < 0.05) only in lakes Prošće and Crniševo. This study showed the applicability of the V9 region of 18S rRNA in ecological status assessment for oligotrophic and mesotrophic lakes due to the comparable results between approaches, but further development and standardization of eDNA metabarcoding are needed for the implementation in routine monitoring programs.

Phytoplankton functional groups as environmental indicators at a high neotropical mountain reservoir in Colombia

Phytoplankton is a fundamental productive component of lentic ecosystems, which also directly reflects environmental variability. This study evaluated the dynamics of phytoplankton in response to the monthly variability of physicochemical properties of a neotropical high Andes reservoir, El Neusa, from July to October 2004. Samples were collected and analyzed for taxonomic identification to species or the lowest possible level and categorized in functional groups (FGs). A total of 111 species of phytoplankton belonging to nine classes and 20 FGs were recorded. Among these phytoplankton classes, Chlorophyceae (36 species), Euglenophyceae (13 species), Bacillariophyceae, (14 species), and Conjugatophyceae (25 species) were the most species-rich and highest in abundance. The overall phytoplankton abundance was largest in August (8.5×104 ±2.7 ×104 ind.L-1) and September (8.9×104 ±4.6×104 ind.L-1); however, the distribution of phytoplankton classes was not statistically different among sampling sites (Friedman-ANOVA; p&gt;0.01) Chlorella sp. (2.4×104 ±2.0×104 ind.L-1), and Chloromonas grovei (2.5×104 ±4.4×103 ind.L-1), belonging to functional group X1, were dominant, representing together between 54% and 78% of the average monthly abundance. Simple correlations and multivariate analysis between physicochemical variables and phytoplankton revealed that conductivity, pH, and total suspended solids had a key influence on the distribution of both dominant species and FGs. These analyses indicated that hydrological (precipitation and runoff) and water stability (stratification and mixing) conditions determined environmental changes and the selection of phytoplankton functional groups. The main features of the dominant FGs and the trophic state of El Neusa were also discussed.

An assessment of the temporal alterations in the trophic status and habitat heterogeneity of the anthropogenically influenced Bhagirathi-Hooghly estuary in reference to phytoplankton community and environmental variables.

The Bhagirathi-Hooghly estuary represents one of the most populated estuaries in the Indian subcontinent with dense settlements along its course. The concomitant high anthropogenic influences and enhancement of nutrient load due to uncontrolled discharges from non-point source in monsoon play important role in habitat variability and consequential changes in the water quality of the estuary. Even though such nutrient loadings are expected to cause significant changes in the ecosystem functioning, a documentation of the habitat heterogeneity has largely remained unavailable from this important yet unmonitored estuary. Thus, the present work aims at assessment of water quality and trophic status of the habitat by application of a combination of abiotic and phytoplankton-specific indices as recommended by different international and national authorities. Results suggest that water quality deteriorated during periods of seasonal precipitation due to enhanced nutrient loadings that culminated in altering the trophic status of habitat. Comparisons with regard to international standards further corroborated the influence of seasonal precipitation on water quality and trophic status of the habitat. Phytoplankton functional groups largely reflected the changing nature of the habitat well, with dominance of those taxa that are more persistent under warm, nutrient replete shallow euphotic depths of the habitat. These findings further suggest that it is essential to regularly monitor the health of this estuarine ecosystem to as to sustain the different life forms that will be essential for the livelihood of people in this area.

Structure of phytoplankton functional groups in shallow lakes with different equilibrium states

Changes in equilibrium states in shallow lakes are associated with disturbances and resilience. The study evaluated the structure and composition of phytoplankton functional groups in two lakes, Lagoa do Paó (turbid waters) and Santa Lúcia (clear waters). Monthly collections of limnological variables and phytoplankton occurred between August 2014 and June 2015 in the pelagic region. The lakes shared five functional groups: K, S1 , X1 , W2 and P, formed by coccoid and filamentous cyanobacteria, coccoid chlorophytes and euglenophytes, and desmids, respectively. The canonical correspondence analysis evidenced a clear separation, highlighting the groups TD, N, W2 and S1 in Santa Lúcia and functional groups composed of potentially toxic cyanobacteria in Lagoa do Paó (SN, Lo), indicating that the submerged macrophyte coverage can act promoting the phosphorous stabilization in the sediment in Santa Lúcia, reducing its contribution to the water column and inhibiting the dominance of the mentioned species. Temperature, pH, phosphorus and light attenuation coefficient influenced the occurrence of H1 , SN, S1 , W2 , X1 , D, and Lo , in the Lagoa do Paó. The composition and structure of the functional groups responded in the two lakes with some functional groups associated with toxic cyanobacteria occurring exclusively in Lagoa do Paó, having also been observed the sharing of some functional groups.

Phytoplankton functional groups as ecological indicators in a subtropical estuarine river delta system

In order to explore new bioindicators of aquatic environments, phytoplankton functional groups (FGs) were applied in a subtropical estuarine river delta system (the Pearl River Delta) for 2012 and 2015. Our results showed that the water quality (physicochemical parameters) of 2015 was better than 2012, which was benefited from Chinese government’s implementation of water pollution control measures. However, a non-metric multidimensional scaling analysis (NMDS) based on phytoplankton FGs similarities did not show interannual differences correspondingly. This implied that the present improvements in water quality were insufficient to affect the interannual alterations of FGs. Among the 29 FGs identified, FGs P and TB were predominant in biomass, with sum proportion of 75%, while other FGs showed occasional advantages either seasonally or spatially, reflecting their randomness of exogenous inflows from water bodies such as lakes and reservoirs. The diversity of dominant FGs could be good bioindicators to spatial and seasonal variations in water quality, since it showed apparently lower in high eutrophic conditions (around Guangzhou city or dry seasons), and higher when water quality was better (the West River side or wet seasons). Therefore, we assumed that continued efforts in improving water quality would finally enhance the diversity of dominant FGs in the study area. In conclusion, the phytoplankton FGs method is suitable for identifying the spatial and seasonal characteristics of aquatic environments greatly affected by human activities, but its sensitivity to interannual water quality improvements requires further investigation.

Phytoplankton diversity and functional group in three urban lakes of Cibinong, West Java, Indonesia

Urban lakes are rapidly becoming vulnerable because of such as anthropogenic pollution and urbanization. Phytoplankton is classified as a biological indicator of lake status. Study was conducted to determined and compared diversity and functional group of phytoplankton including environmental factors in three urban lakes of Cibinong, West Java, Indonesia. The data was collected twice a month from July to October 2018. Three urban lakes showed a different water quality. Phytoplankton composition consists of Chlorophyta, Bacillariophyta, Chrysophyta, Cyanophyta, Pyrrhophyta, Cryptophyta and Euglenophyta division Chlorophyta is more diverse group than other divisions in those three urban lakes. High abundance of Chlorophyta was found in Situ Cibuntu. In Situ Lotus, high of abundance was represented by Bacillariophyta. Temporally, in August, the percentage abundance changes from Chlorophyta to Chrysophyta in Situ Dora. Based on the index diversity, Situ Dora is more stable habitat than Situ Cibuntu and Situ Lotus. The index diversity (H’) and Evenness (J) value of Situ Dora, Cibuntu and Lotus, H’: 1.41-4.03, J: 0.4-0.98; H’: 0.65-2.61; J: 0.2-0.76 and H’: 0.12-2.19, J: 0.11-0.57, respectively. The stability of habitat in Situ Dora was also indicated by the balance of phytoplankton functional group.

The impact of environmental parameters on phytoplankton functional groups in northeastern China

Phytoplankton is an important indicator of biological evaluation of water quality. However, the phytoplankton functional groups can better reflect the functions of aquatic ecosystems. The present study was carried out in the biggest tributary of Ussuri River of boundary between China and Russia. We totally identified 83 species of phytoplankton, which belonging to 17 functional groups from 28 sampling sites in spring (May), summer (July) and autumn (September) in 2017. Phytoplankton functional groups abundance and biomass varied significantly (P<0.05), both seasonally and spatially. Canonical correspondence analysis revealed that phytoplankton functional groups were mainly influenced by dissolved oxygen, permanganate index, water temperature, water depth, total nitrogen and N to P ratio in this basin. Sampling sites were divided into two groups by Non-metric multidimensional scaling analysis, and six phytoplankton species were selected as indicators of river wetland. Fragilaria virescen, Fragilaria capucina and Melosira granulata were used as monitoring indicator species in eutrophic water body. Ceratium hirundinella is the representative species of β-moderate pollution water body. Cymbella ventricosa prefer disturbed site by dredging and reservoir construction especially in the midstream. Chamydomonas ovalis can be used as the indicator of meso-eutrophic status shallow water with high mixing degree from surrounding farmlands in the downstream. The study aim is to provide a scientific basis for the biodiversity conservation and management of water quality.

Resolving Estuarine Nitrogen Use by Phytoplankton Communities Using a Whole Ecosystem Tracer Approach

The use of nutrients by diverse phytoplankton communities in estuarine systems, and their response to changes in physical and biogeochemical processes in these natural systems, is a significant ongoing area of research. We used a whole ecosystem 15NO3− tracer experiment to determine the uptake of different nitrogen (N) forms in phytoplankton functional groups over a mid- to neap tidal cycle in a salt marsh creek in Plum Island Estuary, Massachusetts, USA. We quantified the biomass and δ15N for three groups corresponding to micro- (20–200 μm; microP), nano- (3–20 μm; nanoP), and picophytoplankton (< 3 μm; picoP). All three size classes showed distinct use of recycled N sources throughout the 11-day sampling period and minimal direct assimilation of the 15NO3− tracer. MicroP consistently used high amounts of creek-derived 15NH4+, even with a shift at neap tide from diatom- to dinoflagellate-dominated communities (including members of the harmful genus Alexandrium). NanoP use of recycled 15NH4+ increased over the mid-neap tidal cycle, while picoP use decreased. Both biomass and NH4+ use (as highest δ15N values) of all size groups were maximized during neap tide. This study demonstrates partitioning of recycled N use among size-based phytoplankton groups in the estuary, with distinct effects of tidal cycle on the nutrient uptake of each group, and with important implications for the roles of diverse phytoplankton communities in estuarine nutrient cycling.

Spatiotemporal dynamics of succession and growth limitation of phytoplankton for nutrients and light in a large shallow lake

Understanding the limiting factors of phytoplankton growth and competition is crucial for the restoration of aquatic ecosystems. However, the role and synergistic effect of co-varying environmental conditions, such as nutrients and light on the succession of phytoplankton community remains unclear. In this study, a hydrodynamic-ecological modeling approach was developed to explore phytoplankton growth and succession under co-varying environmental conditions (nutrients, total suspended solids (TSS) and variable N:P ratios) in a large shallow lake called Lake Chagan, in Northeast China. A phytoplankton bloom model was nested in the ecological modeling approach. In contrast to the traditonal ecological modeling, competition between phytoplankton species in our study was modeled at both the species/functional group and phenotype levels. Six phytoplankton functional groups, namely diatoms, green algae, Anabaena, Microcystis, Aphanizomenon and Oscillatoria and each of them with three limitation types (i.e., light-limitation, nitrogen-limitation and phosphorus-limitation) were included in the bloom model. Our results demonstrated that the average biomass proportion of the three limitation types (light-limitation, nitrogen-limitation and phosphorus-limitation) in the six phytoplankton function groups accounted for approximately 50%, 37% and 23% of the total phytoplankton biomass, respectively. TSS suppressed the growth of diatoms and green algae, but favored the dominance of cyanobacteria in Lake Chagan, especially in the turbid water phase (TSS ≥ 60 mg/L). In addition, it was reported that the potential of either N-fixing or non-N-fixing cyanobacterial blooming along the gradients of N:P ratios could exist under the influence of the co-environmental factors in the lake. The proportion of non-N-fixing cyanobacteria (i.e., Microcystis and Oscillatoria) exceeded the proportion of N-fixing cyanobacteria (i.e., Anabaena and Aphanizomenon) when the N:P ratios exceeded 20. Non-N-fixing cyanobacteria would become dominant at higher TSS concentrations and lower light intensities in the turbid water. N-fixing cyanobacteria favored lower N:P ratios and higher light intensities in the clearwater phase (where TSS ≤ 60 mg/L). To sustain a good ecological status in the lake, our results suggest that nutrient and TSS levels in the lake should be maintained at or below the thresholds (TN ≤ 1.5 mg/L; TP ≤ 0.1 mg/L; N:P ratios between 15 and 20; and TSS ≤ 60 mg/L). These findings can help improve water quality management practices to restore aquatic ecosystems.

基于功能类群分析呼兰河口湿地浮游植物群落结构特征

PDF HTML阅读 XML下载 导出引用 引用提醒 基于功能类群分析呼兰河口湿地浮游植物群落结构特征 DOI: 10.5846/stxb201911152444 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（31870187）；哈尔滨师范大学科研启动金项目（XKB201912）；哈尔滨师范大学高等教育教学改革研究项目，哈尔滨师范大学研究生教育教学改革项目 Analysis of phytoplankton structure based on different functional groups in Hulanhe Wetland Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:浮游植物对水环境条件变化敏感，其群落演替特征被广泛应用于指示水环境变化。基于3种浮游植物功能类群方法，对呼兰河口湿地浮游植物群落结构进行研究。于2018年春季（4、5月）、夏季（6、7、8月）和秋季（9、10月）三季，在呼兰河口湿地共设置11个采样点，通过ASNOSIM和SIMPER分析探索FG、MFG和MBFG功能类群的演替特征，基于RDA分析阐述功能类群对环境因子的响应模式。研究期间共鉴定浮游植物243个分类单位，隶属于7门9纲18目32科75属；其种类组成主要以绿藻门（46.09%）、裸藻门（19.34%）和硅藻门（18.52%）为主。共划分FG功能类群25个，MFG功能类群20个，MBFG功能类群6个；ANOSIM分析表明不同季节之间FG和MFG功能类群结构差异显著；SIMPER分析表明S1/Lo/W1/P/J/Y、9b/5a/11b/6a/2c/2d/1c和Ⅲ/Ⅰ类群是影响不同季节之间功能类群变化的主要类群；RDA分析表明，FG、MFG和MBFG功能类群的演替受多种环境因素共同影响，其中pH、BOD5、Tur.和CODMn与功能类群演替关系密切。相较于MBFG功能类群，FG和MFG功能类群能更好的响应呼兰河口湿地水环境的空间异质性。 Abstract:The Hulanhe Wetland is located in northeastern of China, and plays an important role in maintaining the biodiversity and regulating the microclimate in Harbin city. Although phytoplankton functional group studies on wetlands in northern China have increased recently, studies of the phytoplankton functional group in the Hulanhe Wetland are limited. To better understand processes of phytoplankton community succession in relation to environmental parameters, the functional mechanisms of biological communities may be better understood if species are pooled into groups with similar characteristics. Therefore, a detailed survey of three phytoplankton functional groups in spring, summer, and autumn are necessary. In this study, three different phytoplankton functional group methods were used to study phytoplankton community structure. Phytoplankton was qualitatively and quantitatively collected from 11 sampling sites in four typical habitats. The samples were collected in spring (April, May), summer (June, July, August), and autumn (September, October). A total of eleven sample sites were selected. We explored the succession characteristics of FG (Functional Group), MFG (Morpho-Functional Group) and MBFG (Morphology-Based Functional Group) functional groups by applying ASNOSIM and SIMPER analysis. A total of 243 phytoplankton species were identified, belonging to 7 phyla, 9 classes, 18 orders, 32 families and 75 genera. The phytoplankton species composition was dominated by and Chlorophyta (46.09%), followed by Euglenophyta (19.34%), Bacillariophyta (18.52%) and Cyanophyta (11.11%). During the study, the results showed that the average abundance of phytoplankton in the Hulanhe Wetland was significantly different (P<0.05). According to the abundance of phytoplankton, B (Cyclotella Kützing), J (Scenedesmus Meyen, Tetrastrum Chodat), D (Nitzschia Hassall), S1 (Pseudanabaena limnetica (Lemmermann) Komárek), Y (Cryptomonas erosa Hering, Cryptomonas ovata Hering) and W1 (Euglena Ehrenberg, Phacus Dujardin) were dominant in the functional groups. 25 functional groups, 20 Morpho-Functional Groups and 6 Morphology-based Functional Groups were identified during the study. The ANOSIM analysis showed significant differences in FG and MFG functional group structures between seasons. The SIMPER analysis indicated that the primary contributing phytoplankton functional groups were S1/Lo (Merismopedia Meyen)/W1/P (Melosira granulata (Ehrenberg) Ralfs)/J/Y, 9b (small unicells-Chlorococcales)/5a (thin fifilaments Oscillatoriales)/11b (Chlorococcales-Gelatinous colonies)/6a (large Centrics)/2c (small Euglenophytes)/2d (Cryptophytes)/1c (large Euglenophytes) and Ⅲ (large fifilaments)/Ⅰ (small organisms with high S/V). Redundancy Analysis (RDA) based on FG, MFG and MBFG and eleven environmental variables revealed that CODMn was the key factor driving the phytoplankton functional group succession, and Turbidity (Tur.), BOD5 and pH were closely related to phytoplankton functional group patterns. We found that MBFG approach was not as sensitive as FG and MFG approach in describing the variability of phytoplankton groups in the environment. We suggested that MBFG approach was not suitable for indicating the temperate wetland water environment condition. 参考文献 相似文献 引证文献

Bottom-up and top-down effects on phytoplankton functional groups in Hulun Lake, China

The debates about the extent to which phytoplankton in freshwater ecosystems are regulated by top-down or bottom-up forces have been ongoing for decades. This study examines the effects of bottom-up and top-down factors on the phytoplankton functional groups in a eutrophic lake. Phytoplankton and zooplankton were sampled and physical-chemical variables measured from May 2019 to October 2019 in Lake Hulun, China. Approximately 43 phytoplankton species were observed and grouped into 23 functional groups. For the zooplankton, about 27 species were observed and classified into 8 functional groups. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. Water temperature (WT), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), water transparency (SD), and dissolved oxygen (DO) significant influence the biomass of the phytoplankton functional groups. The biomass of phytoplankton functional groups was influenced positively by nutrient availability likely because nutrients influence the growth and reproduction of phytoplankton in freshwater. WT and DO had a positive influence on biomass of phytoplankton functional groups. Conversely, phytoplankton biomass revealed a decreasing trend when SD and Cond significantly increased. This study showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in the lake is not strong enough to produce a negative effect. It is evident that the zooplankton functional groups in Lake Hulun are controlled more by bottom-up force than top-down.

Phytoplankton functional groups in shallow aquatic ecosystems from the semiarid region of Brazil

Abstract: Aim The study analyzed the potential use of the phytoplankton functional groups as an environmental bioindicator in aquatic ecosystems of Brazilian semiarid region. Methods Using data collected over five years of a natural lagoon and two reservoirs, we evaluate the relationship between functional groups and environmental conditions through the multivariate approach. The Q index was applied to assess ecological status in these ecosystems. Results In Panati, the temporary and natural lagoon, the partial habitat desiccation and presence of macrophytes reflected in the less nutrients concentrations and phytoplankton composition, with high biomass of coccoids Chlorophyceae, diatoms and desmids (functional groups J, MP and N, respectively). Taperoá and Soledade reservoirs presented high cyanobacteria contribution, however the biomass and contribution of cyanobacteria in Taperoá (SN, S1) were lower than in Soledade. In this reservoir, cyanobacteria were more abundant, alternating in dominance (LO, M, LM, SN, S1). According to tendencies revealed by Redundancy Analysis (RDA), the main driving abiotic factors on the phytoplankton functional groups were pH, nutrients and light availability. As expected, phytoplankton composition directly influenced the Q index result, showing mostly bad to tolerable conditions in Soledade, medium to good in Taperoá and good to excellent in Panati. Conclusions The Q index was a good tool to assess the water quality and ecological status in aquatic ecosystems from the Brazilian semiarid region, reflecting the influence of natural control mechanisms on the harmful cyanobacteria blooms in temporary ecosystems.

Survival strategies of phytoplankton functional groups to environmental factors in a drinking water reservoir, central China

In this study, use survival strategies of phytoplankton functional groups to environmental factors in a drinking water reservoir. Survival strategies of phytoplankton in drinking water reservoirs were rarely analysed. Dynamics and survival strategies of phytoplankton community in Zhushuqiao Reservoir (Changsha, China) were studied bimonthly from April 2016 to February 2017 to fill this gap. In spring, species of CRS-strategy that adapted to low water temperature, light, and nutrient dominated. There were small individuals of opportunistic colonists of C-strategy observed before stratification. With the increase of nutrient and water temperature in summer, slightly bigger, disturbance-tolerant species of R-strategy and species of CS-strategy that adapted to stratification dominated. In winter, some species adapted to low water temperature, which were R-strategists. Key factors driven seasonal phytoplankton succession were water temperature, total phosphorus, and dissolved inorganic nitrogen. Attention should be paid to potential threats from algal bloom species with C-strategy, and future longer-term monitoring of the system and its surrounding watersheds is greatly needed.

Vertical distribution characteristics of phytoplankton functional groups and their relationships with environmental factors in Lake Basomtso, Tibet, China

Vertical distribution characteristics of phytoplankton functional groups and their relationships with environmental factors in Lake Basomtso, Tibet, China

渭河干流和秦岭北麓典型支流浮游植物功能群特征及水质评价

渭河干流和秦岭北麓典型支流浮游植物功能群特征及水质评价

Phytoplankton community structure in a contrasting physico-chemical regime along the eastern Arabian Sea during the winter monsoon

Abstract The paper describes the community composition of phytoplankton in the eastern Arabian Sea (EAS) during winter monsoon (WM, January–February 2018), encompassing the entire eastern part of the Arabian Sea basin (~6–22°N and 77–67°E) with high-resolution sampling (7 transects, 56 sites), from coastal to offshore regions. The phytoplankton pigment concentrations estimated by high-performance liquid chromatography were interpreted using ‘CHEMTAX’ (Mackey et al., 1996) to determine relative abundance and contribution of phytoplankton functional groups at the class level. A distinct spatial heterogeneity was observed in the distribution of phytoplankton groups in the coastal and offshore regions of the northern as well as southern part of the EAS. The basin-scale column integrated chlorophyll a (Chl a) concentration in the upper 100 m was higher (16–118 mg m−2) in the northeastern Arabian Sea (NEAS) as against 9–79 mg m−2 in the southeastern Arabian Sea (SEAS). The chromatographic analysis revealed the dominance of diatoms in the coastal waters of the EAS basin. A closer evaluation of the hydrodynamics and nutrient chemistry of the offshore regions revealed that entrainment of sub-halocline nutrients into the sunlit water column through convective mixing supported the dominant cyanobacterial population in the NEAS. In the warm oligotrophic waters of the SEAS, the substantially high NH4+ concentration indicates that the dominant prochlorophytes were sustained by the regenerated production. The dominance of large phytoplankton like diatoms indicates a herbivorous control in the food chain in coastal waters of the EAS. Offshore waters are characterised by large proportions of pico-nano plankton along with considerable micro phytoplankton, which suggests a mixotrophic ecosystem. The statistical analysis showed that the silicate (Si/N ratio) concentration played a major role in controlling the diatom abundance in the coastal areas of the north (south) EAS while temperature and salinity together with nutrients structured the phytoplankton assemblage in the offshore waters during WM.

Driving factors affecting the phytoplankton functional groups in a deep alkaline lake

This study evaluated the phytoplankton communities based on functional groups to obtain information about the water quality of Lake İznik, Turkey. The phytoplankton consisted of 103 taxa, classified in 12 phytoplankton functional groups (PFGs), with dominancy of 5 species, Chrysosporum ovalisporum, Dolichospermum mendotae, Planktothrix rubescens, Fragilaria capucina and Mougeotia sp. The Shannon-Wiener diversity index (H') was calculated and results ranged between 0.41 and 2.47. The redundancy analysis (RDA) and Spearman's correlation analysis were used to assess the relationships between the PFGs and environmental variables. According to the multiple comparisons of the data, the main efficient factors that determined the seasonal distribution of the PFGs were TP, DO, SiO2, SD, and pH. The ecological requirements of the dominant PFGs (C, D, F, J, H1, Lo, SN, N, P, R, T, and X2) indicated mainly meso-eutrophic waters. Similarly, Carlson's trophic state index (TSI) stated mesotrophy conditions. As a result, the approach of PFGs can be successfully applied in a deep, alkaline lake to understand the water quality and trophic status.

Lake morphometry underlies physical and chemical parameters affecting the distribution of phytoplankton functional groups in lakes of the Sakarya River Basin (Turkey)

To test the effects of lake morphometry (lake size and depth) on water quality parameters which affect the phytoplankton functional groups (FG) distribution, phytoplankton and some environmental parameters were sampled in November 2017 and May 2018 at the two or three monitoring stations in nine Lakes of Sakarya River Basin (Turkey). Lake size and depth affected phytoplankton FG distribution in both large-sized and small-sized lakes by affecting light availability which was mainly driven by the mixing events during the studied period. Al- though PO4 -P and alkalinity were the other main environmental constraints influencing phytoplankton distribution, they were not directly affected by lake morphometry. Codon Lo was mainly found in small-sized and shallow lakes, whereas coda B, C, D, J, R, and T, which do not have active buoyancy regulation and adapt to high Zmix/Zeu con- ditions, occurred with high relative biovolume in large-sized water bodies.

Seasonal and spatial distributions of morpho-functional phytoplankton groups and the role of environmental factors in a subtropical river-type reservoir.

Phytoplankton is capable of responding to aquatic conditions and can therefore be used to monitor freshwater reservoir water quality. Numerous classification techniques, including morpho-functional approaches, have been developed. This study examined changes in phytoplankton assemblages and water quality, which were sampled quarterly from July 2018 to April 2019. The purpose was to contrast the applicability of three classification approaches (functional, morpho-functional and morphological-based functional groupings) for understanding the spatial and seasonal distribution of the biomass variance in phytoplankton functional groups and their driving environmental factors in the ecological zones of the Shanxi Reservoir through multivariate analysis. The results showed that the phytoplankton biomass was highest in the watercourse zone and lowest in the transition zone. Furthermore, the Shanxi Reservoir was characterized by several cyanobacteria (Microcystis spp.) and numerous bacillariophytes (Asterionella sp., Navicula spp. and Aulacoseira granulata). After evaluating the advantages and disadvantages of morpho-functional classifications, we determined that water temperature appeared to be an essential factor, and the morphology-based functional group approach provided the best results for demonstrating phytoplankton succession, despite having lower sensitivity than the others. Nevertheless, these approaches are all appropriate for identifying and monitoring phytoplankton community structure in aquatic systems of reservoirs with complex terrains.