Dominant Phytoplankton Species Research Articles

Phytoplankton dynamics in a seasonal stratified reservoir (Tillari), Western India

Phytoplankton are the primary producers in all the aquatic ecosystems and play an important role in key biogeochemical processes that are linked to the higher trophic levels and climate variability. The present study deals with the phytoplankton dynamics, biomass and physicochemical features in freshwater reservoir, Tillari, western India. The reservoir experience seasonal stratification and mixing associated changes in the biogeochemical aspects especially the phytoplankton community and chlorophylla(hereafter, Chla). The influence of seasonality was lesser in the deeper water in the reservoir. Buildup in phytoplankton biomass (up to 6.6 mg m−3) was observed in the upper strata of the water column (epilimnion) during the monsoon period (June–July) and winter (December) as a result of nutrient enrichment from the hypolimnion. Among nutrients, nitrate was associated with buildup of Chlain the epilimnion during summer (r2 = 0.7). A total of 91 phytoplankton species were identified with major contribution by charophytes and chlorophytes. The dominant phytoplankton species belonged to generaStaurastrum, Cosmarium, Aulacoseira, NephrocytiumandShroederia.Charophytes made a remarkable presence during the whole study period in the well oxygenated epilimnion as well as in the hypolimnion with relatively low oxygen. Diatom, the major silica sinking group was relatively less abundant. Keeping the importance of the reservoir in view, the understanding of phytoplankton community from this poorly explored reservoir with respect to influencing factors is a very vital baseline information. Thus, to design and evaluate the management strategies for the reservoir, continuous monitoring and processes studies is warranted.

Dynamic analysis of niche and interspecific association of dominant phytoplankton species in Huaxi Reservoir of Guizhou Plateau

Dynamic analysis of niche and interspecific association of dominant phytoplankton species in Huaxi Reservoir of Guizhou Plateau

四川丘陵区水库浮游植物群落结构与蓝藻水华风险——基于优势种生态位与种间联结研究

为了解四川丘陵区中小型水库浮游植物群落结构周年变化，掌握其演替规律并预测其发展方向，于2016年-2017年分季节对该地区10个典型水库进行了周年研究。结果显示：共检出浮游植物9门104属188种，其中优势种4门16属16种，以湖泊假鱼腥藻（Pseudanabaena linmnetica）优势度指数为最高；蓝藻密度在各季节、各水库中均占据优势，尤其是夏季。优势种生态位宽度和生态位重叠度在存在明显的季节差异性，并受到水温、营养条件等环境因子的显著影响；优势种可分为3个类别，竞争力相对较强的7个种中有5种蓝藻；全年发展性最强的种类也多为蓝藻，特别是湖泊假鱼腥藻等具有产毒潜力的种类，其优势度存在进一步扩大的风险。种间联结性检验结果显示，群落种间大致表现出净的正联结，优势种种对间正负关联比大于1，该类水库群落结构较为稳定且存在正向演替的趋势，可能会导致夏季间断性产毒蓝藻水华的风险。研究结果可为四川丘陵区中小型水库浮游植物群落演替研究以及蓝藻水华预警提供基础资料。;Sichuan is known as a province with thousands of rivers and numerous reservoirs which play an important role in production and life. There is a general problem of pollution in small and medium-sized reservoirs in this area, which may affect the structure, function and utilization of aquatic ecosystem. Aiming to explore the annual changes and succession rules of phytoplankton community structure in small and medium-sized reservoirs in hilly regions of Sichuan Province and to predict its development direction, this study conducts an annual survey on 10 typical reservoirs in specific regions in different seasons from 2016 to 2017. The survey identifies a total of 188 species of phytoplankton in 104 genera of 9 phyla, including 16 species (9 species are cyanobacteria) of 16 genera of 4 phyla which are identified as dominant species. In particular, the dominance index of Pseudoanabaena linmnetica is the highest, and the density of cyanobacteria is dominant in all seasons and reservoirs, especially in summer. Furthermore, the improved Levins formula and Petraitis index are applied to determine the niche metrics of the phytoplankton dominant species. The results show that the niche breadth and niche overlap of each dominant species vary seasonally and are significantly affected by water temperature and nutrient. Based on their niche breadth in different seasons, the dominant species are classified into three categories, two of which are relatively competitive. These two categories include 7 species, of which there are 5 species of cyanobacteria, including P. linmnetica. The dominant species in four seasons are mostly in a state of developing, and the most promising species throughout the year are mainly cyanobacteria. In particular, species with the potential to produce toxins such as P. linmnetica have the risk of further expansion of their dominance. The results of interspecific association show a positive correlation among the community species throughout the year, indicating that the community structure in these reservoirs is relatively stable and there is a positive succession trend. In such a trend, intermittent toxic cyanobacteria bloom which affects the quality and function of water may occur in these reservoirs in summer, especially in reservoirs with simple dominant species composition.This paper provides research background for the study of phytoplankton community succession and the early warning of cyanobacteria blooms in small and medium-sized reservoirs in hilly regions of Sichuan Province. To prevent possible filamentous cyanobacteria bloom outbreak, water quality of the reservoirs should be effectively managed and immediately repaired under the dual promotion of high nutritional level and global warming.

ФИТОПЛАНКТОН ОЗЕРА НЕРО В ЛЕТНИЙ ПЕРИОД 2017 г.

The abundance, biomass, and composition of the dominant phytoplankton species in the shallow-water high-trophic lake Nero in June and August 2017 were analyzed. The analysis of its spatial distribution over the water area of the lake, comparison of the data obtained with the results of the previous study period up to 2012–2013, and a statistical analysis of the relationship between phytoplankton abundance and biomass and hydrophysical and some hydrochemical parameters were carried out. The multifactorial limitation of phytoplankton development in summer was established.

Vozdeystviye mezomasshtabnoy vikhrevoy dinamiki na bioproduktivnost' morskikh ekosistem (obzor)

Different types of mesoscale eddy dynamics are considered in the paper from the viewpoint of their effect on the plankton (mainly phytoplankton) amount and its taxonomic structure. The eddy structures of all types, including cyclonic, anticyclonic, water-body anticyclonic and frontal ones, as well as the dipole structures, actively affect plankton. Theoretical schemes of the influencing mechanisms, which are illustrated by the examples of such an impact on the plankton in the Black Sea, are examined. The analyzed responses of the marine plankton ecosystems to the eddy dynamics and the scientific literature review unambiguously testify the important role of these processes in formation of biological productivity in the seas and oceans. Thus, a cyclonic eddy forms the isopycn rise (a domelike bend) in its core both in the thermocline and in the pycno-halocline that elevates nitrocline; it promotes bioproductivity increase. Whereas in the anticyclonic eddy core, the thermocline and pycno-halocline lowering (deflection) takes place; it negatively affects bioproductivity. At that, the isopycn rise occurs at the eddy periphery that, on the contrary, contributes to increase in primary production. In contrast to a conventional anticyclone, a lens-like eddy forms the water rise exceeding the maximum velocity horizon, in other words, in its upper part it often acts like a cyclone. Thus, in any gyre there are the areas where the thermocline rises to the surface and, therefore, the prerequisites for the bioproductivity increase are formed. Strong winds not only enhance the affect of the eddies on biota, but can completely change the nature of this impact. When exposed to wind, the rate of entry of the biogenic elements to the photic layer in the cyclones can decrease, whereas in the lens-like anticyclones it can increase. The important point is that the long-living eddies change the influencing mech-anisms depending on the stage of their evolution. At last, the eddy structures often promote changing in the dominant phytoplankton species that can significantly alter the flow of organic matter to the bottom and affect the global carbon cycle.

Spatial Distribution of Phytoplankton Community Composition and Their Correlations with Environmental Drivers in Taiwan Strait of Southeast China

Large-scale dinoflagellate blooms have appeared in recent decades in the Taiwan Strait, Southeast China. To study spatial variability of phytoplankton community composition, physical and chemical environmental drivers in surface seawater of the Taiwan Strait, we conducted cruises in May and July 2019. Cell numbers of dinoflagellates were significantly higher than that of diatoms in most sampling stations during the cruise in May, whereas diatoms were the major contributor to autotrophic biomass in July. Phytoplankton community shifted from a dinoflagellate- and diatom-dominated system in May to diatom dominance in July. The dominant phytoplankton species (genera) were the harmful algal bloom dinoflagellates Prorocentrum donghaiense and Scrippsiella trochoidea and the diatoms Coscinodiscus in May, and Rhizosolenia, Pseudo-nitzschia, and Guinardia in July. Cell densities of dinoflagellates and P. donghaiense reduced exponentially with increasing seawater temperature and salinity and decreasing dissolved inorganic nitrogen (DIN) concentrations. Based on the results of our work and previous studies, it becomes obvious that harmful dinoflagellate blooms are likely to be a major component of the planktonic food web in the Taiwan Strait at a temperature of 17.0–23.0 °C, a salinity of 29.0–33.0 psu, and a DIN concentration higher than 2.0 μmol L–1.

Species composition and individual abundance of plankton in acid sulfate soil brackishwater ponds in Kotabaru Regency, South Kalimantan Province

This study aims to determine the composition of species and individuals abundance of plankton in acid sulfate soil brackishwater ponds in Kotabaru Regency, South Kalimantan Province. The plankton was collected and preserved with 1% Lugol solution and species was identified by microscope and calculated with cell counting methods. Water quality variables measured in situ; temperature, transparency, salinity, DO, and pH, which existed; total organic matter, NO2-N, NO3-N, NH3-N, PO4-P and total suspended solids. The results showed that in acid sulfate soil ponds, were found 8 species of phytoplankton, classified into 4 classes i.e., Bacillariophyceae (4 species), Cyanophyceae (1 species) Dinophyceae (2 species) and Chlorophyceae (1 species) with an abundance of 10-410 ind./L while zooplankton type were found 9 species classified into 2 classes, i.e. Crustaceae (8 species) and Rotatoria (1 species) with an abundance of 14-637 ind./L. The dominant species of phytoplankton is Nitzschia sp from the Bacillariophyceae class with abundance are 482 ind./L, while the zooplankton type dominated by Copepoda sp from the Crustaceae class with an abundance of 583 ind./L. Value of dissolved oxygen, pH, NO3-N and total suspended solids in the pond are increased parallel with the increasing abundance of Nitzschia sp; otherwise, abundance Nitzschia sp decreased with increasing NH3-N. An abundance of Copepoda sp increased in line with increasing value of dissolved oxygen and pH while decreased with high temperature and NH3-N value.

Studying the Self-Cleaning Ability of Water Bodies and Watercounts of Arshalyn District of Akmola Region

In this paper, the self-purification potential of water bodies and watercourses in the Arshalinsky district was studied in an administrative unit of the Akmola region: Bolshaya Saryoba, Malaya Saryoba, Zhaltyrkol (Arhaniya), Koigeldy, Zhangula, and a section of the Yesil River. The self-cleaning ability of water bodies was assessed by such oxygen indicators as the amount of dissolved oxygen and BOD5. In water samples from water bodies, the dominant phytoplankton and zooplankton species were identified as possible agents or indicators of the self-purification capacity of water bodies. The task of the work was to identify the relationship of self-cleaning ability with inorganic pollution, saprobity.

Variability in primary productivity and bio-optical properties in the Indian sector of the Southern Ocean during an austral summer

The Southern Ocean (SO), in spite of its major contribution to global primary productivity (PP), remains underexplored in this aspect. Light being the most limiting parameter affecting primary production, it is crucial to study the ambient light field to understand PP and associated processes. The current study makes a dual effort to present PP estimates as well as understand the bio-optical variability in the Indian sector of the Southern Ocean (ISSO). Results suggest that PP was highest at Sub-Tropical Front (STF) and lowest at Polar Front-2 (PF2). Most PP profiles were characterized by subsurface maxima, indicating probable photoinhibition or micronutrient limitation at surface layer. Strong correlation between measured and satellite-based integrated PP (R2 = 0.94, RMSE = 77.48, p < 0.01) indicated the efficacy of global models in their original formulation in bio-optically complex SO waters. The maximum photochemical efficiency of phytoplankton (Fv/Fm) measured by fast repetition rate fluorometry varied from 0.1–0.4, implying reduced phytoplankton photosynthetic efficiency in ISSO. The ratio between remote sensing reflectance (Rrs)-derived phytoplankton absorption (aph) at blue-red band (B/R ratio) indicated dominance of smaller phytoplankton in surface and larger phytoplankton at subsurface. Higher Chl-a specific phytoplankton absorption (aph* ) than phytoplankton absorption (aph) suggested an adaptation of dominant phytoplankton species to low light, yet a better light harvest efficiency. However, low contribution of aph suggested a strong influence of non-phytoplankton materials to the total absorption budget. We therefore infer that, the surrounding physical environment in terms of nutrients and bio-optical variability modulated phytoplankton size class and thereby productivity more critically in the surface than in the deeper layers of ISSO.

Taxonomic diversity, size-functional diversity, and species dominance interrelations in phytoplankton communities: a critical analysis of data interpretation

Species diversity, functional diversity, species richness, and dominance are fundamental topics in conservation ecology, but studies on their interrelationship remain underexplored and controversial issues in the literature. This investigation is a critical analysis focusing on the interrelations between species taxonomic diversity (based on the Shannon diversity index), cell size-based functional diversity (as a measure of Rao’sQ), species richness (number of species), and species dominance (as per McNaughton’s dominance index) in marine phytoplankton communities. The results revealed no statistical relationship between Shannon’s and Rao’sQ diversity indices, as well as no correlation between these indices and species richness. The importance of the applied functional diversity metric (Rao’sQ) for data interpretation and the misuse of species richness as a species diversity surrogate in the literature were discussed. The taxonomic composition and cell size of the dominant species and the dominant index over time were described. The species dominance index was related to Shannon’s species diversity and Rao’sQ functional diversity according to a negative linear regression, and the inverse correlation between these properties was statistically significant suggesting the species dominance control over the examined diversity system. Patterns across the data sets of species dominance and total community cell abundance showed resembling temporal fluctuations over a 2-year period, implying that species dominance may be a critical driver affecting temporal variations in total community cell abundance. This work provides a comprehensive critical evaluation of the link between taxonomic and functional diversity, and information on the importance of phytoplankton species dominance in maintaining ecosystem functioning.

Decrease in diatom dominance at lower Si:N ratios alters plankton food webs

Abstract Many coastal oceans experience not only increased loads of nutrients but also changes in the stoichiometry of nutrient supply. Excess supply of nitrogen and stable or decreased supply of silicon lower silicon to nitrogen (Si:N) ratios, which may decrease diatom proportion in phytoplankton. To examine how Si:N ratios affect plankton community composition and food web structure, we performed a mesocosm experiment where we manipulated Si:N ratios and copepod abundance in a Baltic Sea plankton community. In high Si:N treatments, diatoms dominated. Some of them were likely spared from grazing unexpectedly resulting in higher diatom biomass under high copepod grazing. With declining Si:N ratios, dinoflagellates became more abundant under low and picoplankton under high copepod grazing. This altered plankton food web structure: under high Si:N ratios, edible diatoms were directly accessible food for copepods, while under low Si:N ratios, microzooplankton and phago-mixotrophs (mixoplankton) were a more important food source for mesograzers. The response of copepods to changes in the phytoplankton community was complex and copepod density-dependent. We suggest that declining Si:N ratios favor microzoo- and mixoplankton leading to increased complexity of planktonic food webs. Consequences on higher trophic levels will, however, likely be moderated by edibility, nutritional value or toxicity of dominant phytoplankton species.

Phytoplankton community succession in relation to water quality changes in the indoor industrial aquaculture system for Litopenaeus vannamei

Phytoplankton is an important component of aquaculture ecosystem. The succession of dominant species often dominates the trend of phytoplankton community structure balances, which affects the healthy development of aquaculture. To comprehensively assess phytoplankton community succession and explore the major driving factors of this succession in the indoor industrial aquaculture system for Litopenaeus vannamei, a combination of the traditional morphological analysis and high-throughput sequencing were used in the present study. A total of 9 phyla were detected by both methods. Bacillariophyta, Chlorophyta and Cyanophyta were the dominant groups. During the whole process of aquaculture, the succession of phytoplankton community composition in the flowing waters did not follow a clearly regular trend, and ammonia-N and DIN/DIP were the main driving factors. In the aquaculture waters, the dominant species of phytoplankton changed from Thalassiosira to Actinocyclus and Picochlorum. The increase in salinity and decrease in silicate-SiO2 concentrations were the main factors that drive this temporal succession. Some picophytoplankton (≤2 μm) and small nanophytoplankton (>2 μm and ≤ 10 μm) were detected by high-throughput sequencing but not observed by morphological analysis. Picophytoplankton represented 22.22% of total phytoplankton sequence abundance, and small nanophytoplankton accounted for 27.45% of total phytoplankton.

Ecophysiology of a successful phytoplankton competitor in the African flamingo lakes: the green alga Picocystis salinarum (Picocystophyceae)

Picocystis salinarum is a globally widespread picoplanktonic green alga of saline lakes. This tiny alga has been recorded in four continents, and in some cases, it has become the dominant phytoplankton species. We examined the ecophysiology of a Kenyan strain of P. salinarum, collected from Lake Nakuru. The photosynthetic activity of the species was measured in seventy-two combinations of light intensity and temperature. The photosynthetic activity was low along the temperature gradient with an optimum at 31.9 °C; it varied between 0.097 and 1.233 μg C μg−1 Chl a h−1. The ability of P. salinarum to utilize low light intensity (α varied between 0.0061 and 0.1 (μg C μg−1 Chl a h−1) (μmol photons m−2 s−1)−1) and its susceptibility to photoinhibition at different temperatures confirm the species’ preference for low light intensity, which is already shown by its Ik values (1.0–89.3 μmol photons m−2 s−1). The salinity tolerance of P. salinarum, more specifically the effect of changes in the concentration of chloride (NaCl) and carbonate forms (Na2CO3 and NaHCO3), was investigated in continuous cultures. The dominant ion of the medium greatly affected the growth of P. salinarum: significantly higher growth rates were recorded in carbonate form-dominated media as compared to chloride-dominated ones; the highest growth rate was observed at the highest concentration. The observed physiological properties (slow growth, low photosynthetic activity) are not typical of a dominant species; however, the high conductivity tolerance could be a key factor explaining the success of P. salinarum.

Ecological characteristics of dominant phytoplankton community in Lake Nanhai (Baotou) during freezing-thawing period

为了探究包头南海湖浮游植物群落特征和物种与生境之间的关系，于2018年11月和2019年1月、3月分别对南海湖浮游植物群落结构进行调查分析，得出南海湖冻融期浮游植物群落结构为绿藻-硅藻-蓝藻型.使用改进的Levins公式和Petraitis指数测定了南海湖冻融期优势种的生态位量度.结果显示：在不同生境条件下，物种生态位宽度存在季节性变化，同样，生态位重叠也随季节变化而变化.随着湖面冰冻，多数浮游植物生态位宽度有所下降；结冰期生态位重叠程度最高，融冰期生态位重叠程度最低.综合冻融过程优势藻种生态特征，绿藻门的四尾栅藻（Scenedesmus quadricauda）是冻融过程中最主要优势种，优势度、密度、生态位量度均优于其他优势藻种，能充分利用环境资源，更具竞争力.优势种与环境因子的灰关联分析显示，pH是影响浮游植物优势种数量的主要相关因子.;This study investigated the phytoplankton community structure and their relationship with habitats in Lake Nanhai of Baotou city, based on the data from November 2018 and January and March 2019 respectively. It found that the phytoplankton community comprised of Chlorophyta-Bacillariophyta-Cyanophyta in the freezing-thawing period. The niche traits of the dominant species in the freezing-thawing period were determined by using the improved Levins Niche Breadth Index and Petraitis Index. Results showed that there were seasonal changes in the niche breadth of the species under different habitats. Similarly, the niche overlap also changed with the seasons, with highest values during the icing period and lowest during the ice-melting period. Scenedesmus quadricauda was the most dominant species in the process of freezing and thawing. It's dominance degree, density, niche breadth and niche overlap are superior to other dominant phytoplankton species, and it can make full use of environmental resources, and be more competitive. Grey correlation analysis between dominant species and environmental factors showed that pH was the main factor affecting the density of dominant species of phytoplankton.

Phytoplankton assemblage with relation to water quality in Turag River of Bangladesh

The study was performed to evaluate phytoplankton assemblage, physical and chemical characteristics of water, interrelationship between phytoplankton assemblage and physical/chemical characteristics of water and to evaluate water quality index during November, 2015 - September, 2016 for Turag River that is located on the north-eastern side of Dhaka city, Bangladesh. Water samples were collected during winter (November - January/2015-2016), summer (March-May/2016) and rainy season (July September/2016). During the study, the overall phytoplankton assemblage exhibited the following pattern: Bascillariophyceae (40.33%) > Chlorophyceae (32.90%) > Euglenophyceae (14.56%) > Cyanophyceae (12.20%). Fragillaria crotonensis, Navicula grimmei, Phacus circulatus, Euglena agilis, Chlorococcus minutum and Trachelomonas goossensii were dominant phytoplankton species. The average values of water temperature, total dissolved solids (TDS), electric conductivity (EC), pH, dissolved oxygen (DO), biological oxygen demand (BOD5), total nitrogen (TN) and dissolved phosphorus (DP) were 25.94°C, 273.46 mg L-1, 489.71µS cm-1, 6.81, 2.89 mg L-1, 3.85 mg L-1, 8.55 mg L-1 and 0.62 mg L-1, respectively. Euglenophyceae displayed significant negative correlation with DO in winter while TDS in rainy season. Chlorophyceae exhibited significant negative correlation with DP in rainy season. Shannon-Weaver’s (H') and Simpson’s (D) diversity indices ranged between 2.58-3.01 and 0.91-0.95, respectively. In summer, the value of H' (3.01) indicated slight pollution. In winter and rainy seasons, the values of H' were 2.58 and 2.98, respectively displaying light pollution in Turag river. Measured water quality index (WQI) values were 229.71, 171.23 and 74.18 in winter, summer and rainy season, respectively exhibiting that water was unsuitable for drinking purposes in winter and summer and also very poor water quality in rainy season, respectively. The implication of these findings can be used to monitor health of riverine ecosystems which provide ecosystem services for society.

Analysis of long-term dynamics of the plankton community of Lake Baikal

Analysis of long-term observations after plankton community of Lake Baikal has demonstrated the tendencies of the increase of the temperature of water for the upper 50 m layer for the last 70 years, of water transparency and chlorophyll a concentration during the season of the open water for the last 40 years. Analysis of the dynamics of the dominant species of phytoplankton has shown the increase of number of non-endemic small-cell species of diatom algae Synedra acus some increase of the number of endemic species Gymnodinium baicalense with simultaneous tendency of decrease of the number of endemic large-cell species of under-ice developing diatom algae. Analysis of dynamics of number of zooplankton has demonstrated that the number of copepods, of endemic under-ice as well as non-endemic year-round rotifers are decreasing, while the number of cladocers, and non-endemic rotifers, developing during end of summer and autumn increases during the last 70 years. We have fulfilled comparative analysis of the results of our monitoring observations of Lake Baikal plankton and the results for other lakes of the World and we are to conclude that the observed trends can be explained by Global, particularly Climate, Change.

Properties of main phytoplankton species of the Black Sea, determining the change in their dominance in annual dynamics

Using mathematical model, we tested three hypotheses of bloom regulation mechanisms for dominant phytoplankton species in the northeastern Black Sea. The model is based on the concept of intracellular regulation using the Droop equation, and values of the model constants that satisfy the conditions of domination are found. The bloom of the small-cell diatom Pseudo-nitzschia pseudodelicatissima is due to higher specific growth rates than other species in early spring. The half-saturation constants and minimum quotas for mineral nutrition elements (nitrogen and phosphorus) are also relatively high. In late spring and early summer, the bloom of coccolithophore Emiliania huxleyi is usually recorded. Prerequisites are a low half-saturation constant for nitrogen uptake and minimum quota for this nutrient. The third mechanism gains strength in the summer with the deepening of seasonal thermocline and the dominance of large-cell diatoms. It was shown that for the supremacy of large diatom Proboscia alata, it is necessary to have low half-saturation constants for the phosphorus uptake and minimum quotas for this nutrient.

Phytoplankton of the cooling waterbody of the Lukoml state district power station under changing anthropogenic load

The paper presents the results of long-term research of phytoplankton of the cooling waterbody of the Lukoml state district power station (Belarus). The dynamics of abundance, biomass, community structure, and composition of the dominant phytoplankton species for the period of 1972 – 2019 were analyzed. The stages of development of the plankton algae community are determined, due to changes in the intensity and direction of anthropogenic factors. The response of phytoplankton to changes in heat load and dependence on the development of the population of Dreissena polymorpha Pallas is shown. The influence of the fish rearing complex on the developmental intensity and phytoplankton structure was revealed. Since 2004, the periods of intensive vegetation of algae alternate with a significant decrease in abundance and biomass, which indicates the unstable state of the ecosystem of the cooling waterbody. The succession of the dominant complex in 2019 was characterized by the loss of the species Aphanizomenon flos-aquae Ralfs ex Bornet &amp; Flahault (family Nostocaceae) and the inclusion of the species Planktothrix agardhii (Gomont) Anagnostidis &amp; Komárek (family Oscillatoriaceae).

Plankton community of trafficked ports as a baseline reference for Non Indigenous Species arrivals. Case study of the Port of Bar (South Adriatic Sea)

Plankton (ichthyo, zoo and phyto) communities were studied in the temperate shallow waters of the Port of Bar, one of the main cargo ports on the south-eastern Adriatic coast. Sampling was undertaken in February, April, June and October 2015 at 12 stations using the BALMAS Port Baseline Survey protocol. The research was conducted to determine the presence of invasive and potentially toxic plankton species in the port.The most dominant species of ichthyoplankton were eggs and larvae of families Engraulidae, Bothidae and Sparidae with a dominance of Engraulis encrasicolus, Arnoglossus laterna and Diplodus annularis. In addition to ichthyoplankton, sampling of phyto and zooplankton was performed to estimate the abundance and diversity of species.The most numerous zooplankton species throughout investigated period were Penilia avirostris, Euterpina acutifrons, Oithona nana, Acartia clausi, Centropages kroyeri, Paracalanus parvus, Oncaeidae and larvae of Bivalvia. One very unusual occurrence was the spawning of parrotfish Sparisoma cretense (Linnaeus, 1758), a species with Atlantic origin and tropical affinities, whose presence throughout the Mediterranean has shown an increasing trend over the last decade. The most dominant species of phytoplankton were the diatoms Chaetoceros affinis and Chaetoceros spp., Asterionellopsis glacialis, Pseudo-nitzschia spp., Thalassionema nitzschioides, and dinoflagellates Gymnodinium spp. and Prorocentrum triestinum. The potentially toxic species from genus Pseudo- nitzschia reached an abundance of 104 cells L-1. Toxic dinoflagellates Prorocentrum cordatum and P. micans reached values of 103 cells L-1.Although there were no HAOP species found during the survey, presence of several potentially toxic and toxic phytoplankton species whose impact is not sufficiently known indicates the necessity of introduction of regular monitoring activities and definition of preventive protection measures.

Determination of priority areas and principal environmental factors for water ecosystem health remediation

AbstractGlobally, the deterioration of aquatic ecosystems has attracted wide concentrations of scholars and governments, and how to wisely remediate the damaged ecosystem is a hot issue. Determination of prior areas is critical for ecosystem remediation. However, there are very few systematically feasible methods available for comprehensively addressing the issue, and consequently, the benefits of water ecosystem remediation projects are reduced. Therefore, this paper proposes a framework for determining priority areas based on phytoplankton response to environmental factors. Phytoplankton constitute the main component of global aquatic biomes and water blooms. The effects of water ecosystem remediation projects are highly related to phytoplankton. First, we identified the dominant species of phytoplankton using a dominance accumulation model. Then, we determined the main environmental factors of phytoplankton using detrended correspondence analysis and canonical correspondence analysis. Afterwards, we calculated the adaptability of a single species to all principal environmental factors and the responsiveness of all dominant species to a single environmental factor using methods of integrated habitat suitability index and multispecies‐based habitat suitability index. On the basis of these results, we finally developed a new model of the suitability of aquatic biomes to habitat factors (IHSIA) whereby to determine the priority areas and the principal environmental factors by time–space coupling analysis. We applied the method to Jinan, a pilot city for the construction of a civilized ecological city in China. The results indicated that waters in urban areas are priority areas for remediation; principal environmental factors in both the whole study area and the priority areas for phytoplankton are NH3‐N, water temperature, total phosphorus, and dissolved oxygen where the NH3‐N is the most urgent environmental factor to be remediated in the study area. Reducing the concentration of NH3‐N can facilitate phytoplankton biome remediation. We found that dominant phytoplankton species can reflect the actual status of phytoplankton populations and can provide important reference data for global aquatic life research; space–time scale is an important factor in selecting principal environmental factors; limiting environmental factors that are poorly adaptable to dominant species could help provide a new path for water bloom prevention; the newly proposed model IHSIA can make the ecological environment remediation more objective. These results can help water managers reduce the scale of phytoplankton biomes by adjusting the environmental factors. The presented framework can provide new ways for water bloom prevention and can serve as the theoretical and scientific basis for the high success rate of water ecosystem restoration projects across the world.