Phytoplankton Ecology

Outbreaks of the dinoflagellate Alexandrium catenella have caused significant economic losses to the salmon industry in the south of Chile. However, the precise ichthyotoxic mechanism by this paralytic shellfish toxin (PST) – producing dinoflagellate remains poorly understood. The rainbow trout cell line RTgill-W1 assay was used to investigate fish gill damage by multiple A. catenella strains under different environmental conditions, and potency of whole cells, lysed cells and culture medium were compared. Cytotoxic potency was highly variable among strains and strongly correlated to dinoflagellate cell- abundance. Lysed cells produced more gill damage than intact cells and supernatant, reducing gill cell viability down to 20% of controls at 4000 cells mL􏰀1. However, gill cells exposed to pure PST fractions (C1&C2, STX, GTX 1&4) exhibited only very limited loss of viability (<30%), even at cell concentrations equivalent to exceeding those detected in southern Chilean fjords. A. catenella lytic compounds rapidly (1–4 days) degraded in the light, but were pH (7–9) and temperature stable (17–85 8C), thus arguing against the involvement of proteinaceous compounds. Superoxide production by Chilean dinoflagellate strains was as high as by the raphidophyte Chattonella marina (max. 8.67 􏰂 0.14 pmol O2􏰀 cell􏰀1 h􏰀1), variable among strains and enhanced by cell disruption and environmental stress (low nutrients, low salinity, low or high pH). Fatty acid profiles included high concentrations of the long-chain (􏰃C20) polyunsaturated fatty acids (PUFA) – docosahexaenoic acid (DHA, 22:6v3; 16–20% of total fatty acids) in addition to several other PUFA, which were highly cytotoxic against gill cells as a purified fraction (LC50 1.30 mg mL􏰀1). In addition, potency was enhanced 9-fold in combination with superoxide anion (LC50 0.15 mg mL􏰀1). In conclusion, the present study demonstrates that fish gill damage during A. catenella fish-kill events in Chilean fjords cannot be explained by PST toxins, but can to a large extent be accounted for by the synergistic interaction between ROS (superoxide anion) and DHA, and potentially other PUFA, notably under conditions that promote cell lysis.

The growth and toxin production of a Philippine  Pyrodinium bahamense isolate in nutrient replete batch cultures were investigated at various stages of the life cycle  and under conditions affected by varying salinity, temperature and combined effects of salinity and temperature. The organism was routinely maintained in sterile seawater enriched with F/2 medium at 24±2°C, 150 uEm-2s-1  under a 12: 12 h  light : dark (L:D) cycle.  Early exponential growth stage was reached after 7 days with a cell division rate of 0.26 div day-1. The toxin content reached a peak of 298 fmol cell-1 at mid exponential phase (14 days) and  rapidly declined to 54 fmol cell-1 as the organism approached  the death phase. Only three sets of toxins composed of STX, dcSTX and B1 were detected. NeoSTX, GTX1-6 and C toxins were not produced during the entire growth cycle. The organism was able to grow  from 26 to 36 0/00 with an optimum growth at 36 0/00. Growth rate was highest at 36 0/00  (0.4 div d-1 ) while the toxin content was highest at 30 0/00 (260 fmol cell-1 ). A decline in STX composition (from 80 to 65 mole %) was observed with increased salinity while dcSTX composition increased from 15 to 32 mole %. B1 toxins remained constant in all the salinity variations conducted. P. bahamense was able to grow from 23 to 36°C and the optimum temperature for growth  was at 25°C. Lowest growth rate (0.22 div day-1 ) was observed at  25°C, while highest growth rate was  achieved  at 0.4 div day-1 at 35°C. Toxin content  reached a peak of 376 fmol cell-1 at 25°C and was lower ( 80 to 116 fmol cell-1 ) at  higher temperatures (32 to 35°C). STX made up to 85 to 98 mole % toxin cell-1. However, a 50% decrease in mole % toxin cell-1 STX was observed at 36°C with increased proportion of dcSTX and B1. No dcSTX was produced at temperatures from 25 to 34°C.  Combined effects  of salinity and temperature showed that P. bahamense was not able to grow at low salinity and temperature (26 0/00 – 28°C). Optimum growth was observed in  higher salinities at all temperature conditions.  Highest specific growth rate was 0.4 div day-1 at 30 0/00  - 32°C, while toxin content peaked at 30°-25 0/00  amounting to 665 fmol cell-1. STX comprised about 80 to 99 mole % toxin cell-1 .

A large patch of anomalously warm water (nicknamed “the Blob”) appeared off the coast of Alaska in the winter of 2013–2014 and subsequently stretched south to Baja California. This northeastern Pacific warm-water anomaly persisted through the end of 2015. Scientists and the public alike noted widespread changes in the biological structure and composition of both open ocean and coastal ecosystems. Changes included geographical shifts of species such as tropical copepods, pelagic red crabs, and tuna; closures of commercially important fisheries; and mass strandings of marine mammals and seabirds. The
ecological responses to these physical changes have been sparsely quantified and are largely unknown. Here, we provide a bottom-up summary of some of the biological changes observed in and around the areas affected by the Blob.

Changes in the Arctic atmosphere, cryosphere and Ocean are drastically altering the dynamics of phytoplankton, the base of
marine ecosystems. This Review addresses four major complementary questions of ongoing Arctic Ocean changes and associated
impacts on phytoplankton productivity, phenology and assemblage composition. We highlight trends in primary production
over the last two decades while considering how multiple environmental drivers shape Arctic biogeography. Further, we
consider changes to Arctic phenology by borealization and hidden under-ice blooms, and how the diversity of phytoplankton
assemblages might evolve in a novel Arctic ‘biogeochemical landscape’. It is critical to understand these aspects of changing
Arctic phytoplankton dynamics as they exert pressure on marine Arctic ecosystems in addition to direct effects from rapid
environmental changes.

There is high confidence that the anthropogenic increase of atmospheric greenhouse gases (GHGs) is causing modifications in the Earth's climate. Coastal waterbodies such as estuaries, bays and lagoons are among those most affected by the ongoing changes in climate. Being located at the land-sea interface, such waterbodies are subjected to the combined changes in the physical-chemical processes of atmosphere, upstream land and coastal waters. Particularly, climate change is expected to alter phytoplankton communities by changing their environmental drivers (especially climate-related), thus exacerbating the symptoms of eutrophication events, such as hypoxia, harmful algal blooms (HAB) and loss of habitat. A better understanding of the links between climate related drivers and phytoplankton is therefore necessary for projecting climate change impacts on aquatic ecosystems. Here we present the case study of the Zero river basin in Italy, one of the main contributors of freshwater and nutrient to the salt-marsh Palude di Cona, a coastal waterbody belonging to the lagoon of Venice. To project the impacts of climate change on freshwater inputs, nutrient loadings and their effects on the phytoplankton community of the receiving waterbody, we formulated and applied an integrated modelling approach made of: climate simulations derived by coupling a General Circulation Model (GCM) and a Regional Climate Model (RCM) under alternative emission scenarios, the hydrological model Soil and Water Assessment Tool (SWAT) and the ecological model AQUATOX. Climate projections point out an increase of precipitations in the winter period and a decrease in the summer months, while temperature shows a significant increase over the whole year. Water discharge and nutrient loads simulated by SWAT show a tendency to increase (decrease) in the winter (summer) period. AQUATOX projects changes in the concentration of nutrients in the salt-marsh Palude di Cona, and variations in the biomass and species of the phytoplankton community.

During the June 2010 survey of phytoplankton and physicochemical parameters in the Krka River estuary (eastern Adriatic Sea), a cryptophyte bloom was observed. High abundance of cryptophytes (maximum 7.9×106 cells l–1) and high concentrations of the class-specific biomarker pigment alloxanthine (maximum 2312 ng l–1) were detected in the surface layer and at the halocline in the lower reach of the estuary. Taxonomical analysis revealed that the blooming species was Plagioselmis cf. prolonga. Analysis of the environmental parameters in the estuary suggested that the bloom was supported by the slower river flow as well as the increased orthophosphate and ammonium concentrations. The first record of a cryptophyte bloom in the Krka River estuary may indicate that large-scale changes are taking place in the phytoplankton community. Such changes could have a major impact on the natural ecosystem dynamics and the mariculture production in the area.

The primary productivity of a polluted mangrove pond in Lagos was investigated for six months (October 2010-March 2011) using the chlorophyll-a method. Air and water temperatures were high (≥21°C) while transparency was lower than 11.5 cm at the mangrove pond. Total suspended solids were ≥2.0 mg/L while total dissolved solids values remained high (≥284 mg/L) only between October 2010 and December 2010. Salinity and conductivity values were ≤4.2 ‰ and ≤6600 µS/cm respectively throughout the sampling period. Dissolved oxygen values were relatively low (≤5.1mg/L) while biochemical oxygen demand and chemical oxygen demand values were high (≥8.0 mg/L). Reactive phosphorus, reactive nitrogen, sulphate, reactive silicate values ranged between 0.03 mg/L and 3.70 mg/L, 0.20 mg/L and 5.30 mg/L, 0.01 mg/L and 2.63 mg/L, 0.01 mg/L and 0.23 mg/L respectively during the sampling period. Chlorophyll-a values ranged from 0.001 µg/L-0.005 µg/L at the mangrove pond. Heavy metals occurred all through the sampling period as traces. Trophic state index (TSI) values using reactive nitrogen showed oligotrophic to eutrophic conditions. The microalgal taxa were dominated by pennate forms notably Bacillaria paradoxa Gmelin, Cymbella minuta Hilse, Navicula cuspidata Kutzing and a few centric formsCoscinodiscus centralis Ehrenberg and Coscinodiscus radiatus Ehrenberg.

1. Ecologists often group organisms based on similar biological traits or on taxonomic criteria. However, the use of taxonomy in ecology has many drawbacks because taxa may include species with very different ecological adaptations. Further, similar characters may evolve independently in different lineages. 2. In this review, we examine the main criteria that have been used in the identification of nine modes of classifying phytoplankton non-taxonomically. These approaches are based purely on morphological and/or structural traits, or on more complex combinations including physiological and ecological features. 3. Different functional approaches have proved able to explain some fraction of the variance observed in the spatial and temporal distribution patterns of algal assemblages, although their effectiveness varies greatly, depending on the number and characteristics of functional traits used. The attribution of functional traits to single species or broad groups of species has al...

Despite improvements in wastewater treatment systems, the impact of anthropogenic nutrient sources remains a key issue for the management of European lakes. The Water Framework Directive (WFD) provides a mechanism through which progress can be made on this issue. The Directive requires a classification of the ecological status of phytoplankton, which includes an assessment of taxonomic composition. In this paper, we present a composition metric, the plankton trophic index, that was developed in the WISER EU FP7 project and demonstrate how it has been used to compare national phytoplankton classification systems in Northern and Central Europe. The metric was derived from summer phytoplankton data summarised by genus from 1,795 lakes, covering 20 European countries. We show that it is significantly related to total phosphorus concentrations, but that it is

The research was conducted to study the diatoms in a lotic ecosystem (Al- Shamiyah River) and related physicochemical factors for the period from March 2013 to January 2014. Four sites were selected along the river and the study included measuring the temperature (air and water), water flow rate, turbidity, light penetration, pH,  total available carbon dioxide, dissolved oxygen, biochemical oxygen demand, electrical conductivity, salinity, total suspended solids, total dissolved solids, total alkalinity, hardness, calcium, magnesium, nitrite, nitrate, phosphate and silicate. Furthermore, the quantitative and qualitative studies of diatoms were done. A total of 144 taxa of diatoms was identified with predominate of pennate diatoms (129 species), while the centric diatoms were 15 species.  The recorded identified diatoms were 83, 68, 74 and 81 species in sites 1, 2, 3 and 4, respectively. Total number of diatoms ranged 16347.7- 31514.6 cell x 103/l. High values of diversity indices were recorded in this study. The results revealed that the river was not under pollution stress.

Phytoplankton groups are one of the major quality element to be used in the evaluation of the trophic and ecological state of freshwater ecosystems according to the EU Water Framework Directive. This research was made to assess the trophic and ecological status of Lake Bafa in Turkey, on the basis of phytoplankton communities. Büyük Menderes River is one of the most important factor that carries pollutants to Lake Bafa. The eight sampling station were assigned to evaluate the ecological and trophic state of the lake. Phytoplankton species were collected monthly for 2 years study period. Most commonly used phtoplankton indices Q index and Carlson's Trophic State Index (TSI), and different versions of diversity indices were used to estimate trophic and ecological state of the lake. Similarities between the sampling stations were clustured by using the unweighted pair group method using arithmetic average (UPGMA), based on phytoplankton communities. Correlations between the applied indices were determined by using Pearson Correlation. After the identification of collected phytoplanktons, total of 63 taxa which belong to classis of Cyanophyceae (11.2%), Bacillariophyceae (49.2%), Chlorophyceae (23.8%), Xanthophyceae (1.5%), Euglenophyceae (11.2%) and Dinophyceae (3.1%) were detected. The 1 st and 2 nd stations were the most similar stations to each other (88%) according to phytoplankton communities. Secchi disc depth (SD) and TP played an important role in the distribution of phytoplankton species in Lake Bafa. The highest significant positive correlation was determined between Q and TSI (r = 0.987, p˂0.01). Considering the TDI values in the phytoplankton composition of the lake, it can be said that although the productivity status of the studied lake is still "mesotrophic", it has a tendency towards "eutrophic" state. According to the Q values, the first five stations reflect the moderate ecological state, while the 6 th , 7 th and 8 th stations represent the poor ecological state.

This study was aimed to investigate the trophic status of the marshes by phytoplankton diversity. The Phytoplankton community and four biodiversity indices were studied in Auda marsh southern Iraq in the period between January 2018 to January 2019. A total of 146 species were identified belonging to 8 classes as follows: Bacillariophyceae (85 taxa), Euglenophyceae (26 taxa), Cyanophyceae (16 taxa), Chlorophyceae (11 taxa), Mediophyceae (3 taxa), Coscinodiscophyceae (2 taxa), Conjugatophyceae (1 taxa), Trebouxiophyceae (1 taxa), and  Dinophyceae (1 taxa). The most predominant diatom was Nitzschia (15 species), and followed by the other genera Phacus (11 species), Navicula  and Euglena (10 species). The Shannon-Weiner diversity, Richness index  and Evenness index  were recorded a low value in wet 2019 and a high values in wet  (for Shannon Weiner and Evenness indices)  and dry  ( for Weiner and Evenness indices) 2018.  The Jaccard index showed equal similarity between study sites, while the highest seasonal similarity was recorded between wet and dry 2018 and lowest similarity was between wet2018 and wet2019. According to the biodiversity indices Auda marsh has high diversity. The results revealed that Auda marsh is mesotrophic according to phytoplankton species composition.

Sundarbans delta is one of the dynamic mangrove dominated estuarine
deltas of the world (Banerjee et. al, 2012), which is situated at the apex of
Bay of Bengal. A major portion of this delta (62%) lies in Bangladesh and
the remaining 38% is within the Indian sub-continent. In the Indian
Sundarbans, approximately 2069 sq. km of area is occupied by the tidal
river system or estuaries, which finally end up in the Bay of Bengal. These
estuaries feed several brackishwater ponds in the area. We selected three
0 ponds in the Kakdwip area of Indian Sundarbans (21 52'35.7"N &
0 88 11'55.0?E) and treated them differently to observe the effect of iron
addition on cell volume and cell carbon of six major Coscinodiscus species
available in the present study area (Mitra et. al, 2004). The variation of
phytoplankton standing stock is reflected through phytopigment level
and therefore chlorophyll a along with nutrients were also analysed
simultaneously in these three ponds

A B S T R A C T Certain physico-chemical parameters of Bordoi Bilmukh Bird's Sanctuary, a wetland were investigated by taking mean value of water samples collected from different sampling sites from August 2013 to July 2014. The primary objective of this study is to present a statistically meaningful water quality database of Bordoibam Bilmukh Bird's sanctuary by employing Normal Distribution Analysis for better management of wetland water and will also help in future to assessthe quality of wetland water. The result of present study showed that hydrological parameters exhibit non uniform distribution in the study areas of the wetland and indicate that it is a pollution free environment.

A better understanding of the vast range of plankton and their interactions with the marine environment would allow prediction of their large-scale impact on the marine ecosystem, and provide in-depth knowledge on pollution and climate change. Numerous technologies, especially lab-on-a-chip microsystems, are being used to this end. Marine biofouling is a global issue with significant economic consequences. Ecofriendly polymer nanotechnologies are being developed to combat marine biofouling. Furthermore, nanomaterials hold great potential for bioremediation and biofuel production. Excellent reviews covering focused topics in plankton research exist, with only a handful discussing both micro- and nanotechnologies. This work reviews both micro- and nanotechnologies applied to broad-ranging plankton research topics including flow cytometry, chemotaxis/toxicity assays, biofilm formation, marine antifouling/fouling-release surfaces and coatings, green energy, green nanomaterials, microalgae immobilization, and bioremediation. It is anticipated that developments in plankton research will see engineered exploitation of micro- and nanotechnologies. The current review is therefore intended to promote micro-/nanotechnology researchers to team up with limnologists/oceanographers, and develop novel strategies for understanding and green exploitation of the complex marine ecosystem.

A.Sadchikov, S.Ostroumov. Use of dissolved organic matter by microorganisms: formation of water quality in a pond of high trophic level. Fisheries. 2020, No.5, p.25-29. DOI  10.37663/0131-6184-200-5-25-29; Утилизация растворенного органического вещества микроорганизмами: формирование качества воды в высокотрофном пруду.
https://www.academia.edu/44887672/;

Abstrak Dominansi suatu jenis fitoplankton pada suatu badan air ditentukan oleh perbandingan jenis nutrien yang terlarut dalam badan air, tapi dominasi fitoplankton di suatu perairan tidak selamanya menguntungkan perairan tersebut. Perubahan kondisi lingkungan akan merangsang fitoplankton tumbuh meledak sehingga menimbulkan blooming. Kegiatan budidaya dapat berpengaruh terhadap kondisi kualitas perairan suatu waduk, karena sisa pakan dan sisa metabolisme yang menumpuk di dasar perairan dapat menyebabkan terjadinya eutrofikasi pada waduk tersebut dan dapat menimbulkan blooming fitoplankton. Tulisan ini bertujuan memberikan informasi fitoplankton dominan apa saja yang terdapat di Waduk Jatiluhur dan pengaruhnya terhadap perairan tersebut. Dari hasil pengamatan, jenis fitoplankton yang dominan di Waduk Jatiluhur adalah Microcystis sp, Oscillatoria sp (filum Cyanophyta), Ceratium sp dan Peridinium sp (filum Pyrrophyta). Walaupun blooming beberapa jenis fitoplankton tidak menimbulkan racun, tapi dapat mempengaruhi sumberdaya yang ada di perairan karena menyebabkan tekanan terhadap suatu ekosistem. Kata kunci: Fitoplankton, Waduk Jatiluhur Pengantar Fitoplankton dapat disebut sebagai produsen pertama, karena secara historis hidup paling dulu di dunia. Secara de facto, jika terbentuk danau baru, maka yang pertama hidup di danau tersebut adalah fitoplankton, bukan produsen lain seperti rumput air atau tumbuhan tingkat tinggi lainnya. Eksistensi fitoplankton sangatlah besar di perairan, karena fitoplanktonlah yang pertama membangun bahan organik dan penghasil oksigen terbesar di perairan melalui proses fotosintesis yaitu sekitar 90-95% (Schimittou, 1991). Faktor lingkungan fisik (abiotik) yang mempengaruhi pertumbuhan dan perkembangan fitoplankton adalah angin, arus, ketersediaan makanan (kandungan unsur hara) dan aktivitas pemangsaan (Davis, 1955). Komunitas fitoplankton di perairan waduk dan danau cenderung didominasi oleh jenis-jenis dari kelas Chlorophyceae, Cyanophyceae dan Bacillariophyceae. Dominansi suatu jenis fitoplankton pada suatu badan air ditentukan oleh perbandingan jenis nutrient yang terlarut dalam badan air. Hal ini disebabkan setiap jenis fitoplankton mempunyai respon yang berbeda terhadap perbandingan jenis nutrien yang ada terutama nitrogen dan fosfor dalam badan air. Tetapi dominasi fitoplankton di suatu perairan tidak selamanya menguntungkan perairan tersebut. Perubahan kondisi lingkungan akan merangsang fitoplankton tumbuh meledak sehingga menimbulkan blooming. Yang dimaksud dengan blooming adalah suatu peristiwa di mana suatu spesies dalam waktu singkat berkembang sangat pesat dengan jumlah yang melampau rata-rata produksi bulanan dalam keadaan normal (Basmi, 1994). Faktor-faktor yang memicu terjadinya blooming diantaranya adalah Upwelling dan hujan lebat, kedua peristiwa tersebut dapat membalikan massa air sehingga unusr hara yang terdapat di dasar perairan terangkat ke permukaan yang kaya akan sinar matahari sehingga memicu pertumbuhan fitoplankton. Kegiatan budidaya ikan dalam Keramba Jaring Apung (KJA) di Waduk Jatiluhur telah dimulai pada tahun 1976 dan sejak tahun 1988 kegiatan tersebut mengalami perkembangan baik dalam jumlah unit maupun produksinya. Kegiatan budidaya ini dapat berpengaruh terhadap kondisi kualitas perairan waduk, karena adanya sisa pakan dan sisa metabolisme yang menumpuk dapat menyebabkan terjadinya eutrofikasi pada waduk tersebut dan dapat menimbulkan blooming fitoplankton. Tulisan ini bertujuan memberikan informasi fitoplankton dominan apa saja yang terdapat di Waduk Jatiluhur dan pengaruhnya terhadap perairan tersebut.

Seasonal and spatial changes of phytoplankton in relation to environmental variables
affecting the water quality were investigated along the main channel of Lake Nasser throughout
2013. In total, 104 phytoplankton species, belonging to 7 classes, were identified. Phytoplankton
assemblages were dominated by Bacillariophyceae, Cyanophyceae and Chlorophyceae, whereas
Dinophyceae, Euglenophyceae, Chrysophyceae and Cryptophyceae were infrequent. Cyclotella
glomerata, C. ocellata and Aulacoseira granulata represented the most abundant species among
Bacillariophyceae. Cyanophyceae was dominated by Planktolyngbya limnetica and Eucapsis
minuta, and Chlorophyceae by Ankistrodesmus fusiformis and Staurastrum paradoxum. The
water column was thermally stratified during summer, while being mixed throughout winter.
Phytoplankton features and physicochemical variables were analyzed with the principal component
analysis. Electrical conductivity and water temperature were the most common factors
negatively controlling phytoplankton density. Phytoplankton density was positively associated
with NO3, whereas it was negatively correlated with PO4 and HCO3. Cyanophyceae were strongly
adapted to the environmental variables and NO2 was limiting their growth. Chlorophyceae
were more dependent on PO4 than NO3. The vertical distribution of Chl a was associated with
the summer thermal stratification and its concentration increased southwards. Chl a was affected
by NO2 and linked to Chlorophyceae. The regional variations of phytoplankton reflected its
response to varying environmental conditions. The annual average of the trophic state index
indicated eutrophic waters of Lake Nasser.

On the basis of our collected material and historical information we assess phytoplankton dynamics in Kondopoga Bay, the
Lake Onego in 1993-2011. The summer communities from continuously studied sampling stations contain 100 species belonging to
eight divisions: Bacillariophyta, 40; Chlorophyta, 25; Cyanobacteria, 13; Chrysophyta, 12; Euglenophyta, 2; Dinophyta, 4; Cryptophyta,
3; and Xanthophyta, 1. Sample richness varied between 16 and 54 species, with a negative overall trend during the study
period, but increases in Cyanobacteria and Dinophyta. Bioindication analysis shows that water acidification slowly rising from
1993 to 2011 with organic pollution (Index saprobity S) and the number of species with heterotrophic ability. In 1990s, the total
abundance and biomass were on average 1.5 times higher than in 2000-2011, having similar fluctuation ranges (Pearson 0.74),
with peaks in 1996 and 2006. At the same time, species richness decreased, showing a depletion of algal communities. Two critically
impacted periods are revealed with the Shannon index in 1996 and 2007 and on the basis of the Aquatic Ecosystem State Index
(WESI) calculation in 1995 and 2007, related to Kondopoga industrial wastewater influx enriched in nutrients and other contaminants.
As a whole, the WESI was extremely high, reflecting a high self-purification capacity in respect to phosphate concentration
in the bay. The canonical corresponded analysis (CCA) shows two different sets of taxa, those stimulated by temperature and nitric
nitrogen (Anabaena scheremetievii Elenkin, Dolichospermum lemmermannii (Ricter) P. Wacklin, L. Hoffmann & J. Komárek, and
Aulacoseira alpigena (Grunow) Krammer), and sensitive autotroph species inhabiting cool to temperate clear waters (Aulacoseira
distans (Ehrenberg) Simonsen, Ankistrodesmus fusiformis Corda ex Korshikov, Mucidosphaerium pulchellum (H.C. Wood) C. Bock,
Proschold & Krienitz). The comparative statistics with GRAPS program revealed two cores of species richness in years 1996 and
2011 that included most of species. The long-term dynamics of relative cell volume shows that phytoplankton communities were enriched
with small-celled species, such as Cyanobacteria (Microcystis aeruginosa (Kützing) Kützing) and Cryptophyta (Cryptomonas
sp. and Katablepharis ovalis Skuja) in the period between 1998 and 2006. Pearson correlation for Shannon index and relative cell
biovolume is negative (-0.79), showing high stability of species rich communities under environmental impacts. Two periods of dinoflagellate
blooms (1998, 2007) followed the peaks of total abundance and biomass (1996, 2006). Such correlation makes the Kondopoga
Bay ecosystem comparable to those of large lakes in spite of a heavier anthropogenic impact from Kondopoga pulp and
paper mill wastewater.

Data on phytoplankton, macrophytes, ben-thic invertebrates and fish from more than 2000 lakes in 22 European countries were used to develop and test metrics for assessing the ecological status of European lakes as required by the Water Framework Directive. The strongest and most sensitive of the 11 metrics responding to eutrophication pressure were phyto-plankton chlorophyll a, a taxonomic composition trophic index and a functional traits index, the macrophyte intercalibration taxonomic composition metric and a Nordic lake fish index. Intermediate response was found for a cyanobacterial bloom intensity index (Cyano), the Ellenberg macrophyte index and a multimetric index for benthic invertebrates. The latter also responded to hydromorpholog-ical pressure. The metrics provide information on primary and secondary impacts of eutrophication in the pelagic and the littoral zone of lakes. Several of these metrics were used as common metrics in the intercalibration of national assessment systems or have been incorporated directly into the national systems. New biological metrics have been developed

We revealed 238 species and infraspecific taxa of algae and cyanobacteria in phytoplankton communities in lakes of the Regional Landscape Park “Slavyansky Resort”, Ukraine during 2007-2013 of the total 352 known in the region assigned to nine taxonomic Divisions with Bacillariophyta, Cyanoprocaryota, and Chlorophyta prevailing. The bio-indication methods applied for the first time characterizes the aquatic environments as slightly alkaline, medium-enriched with oxygen, temperate, clear to moderately polluted, of Water Quality Classes II-III, eutrophic, but with photosynthetic algal nutrition attesting to insignificant concentration of toxic substances despite a considerable anthropogenic impact. The algal diversity is depressed with salinity of the lakes. The statistical analysis defines two clusters, the northern with perennial lakes Ripne, Veysove, Garache, and Slipne, and southern of partially drained lakes Levadne, Chervone, and Lake. Aridity is a major factor of water chemistry inflicting high salinity and depletion of species diversity. Historically salinity might have played a leading role in shaping the algal communities of the region

Phytoplankton is the key factor of primary production in streams and other lotic systems. This study
focused on phytoplankton in bani- Hassan stream in Karabala province. Five sites were selected along the
stream where monthly sampling was carried for 12 months. The physicochemical parameters were studied
in addition to diversity, spatial and temporal variation of phytoplankton and biological diversity indices. A
total of 136 taxa of phytoplankton were identified which belonged to 65 genera . Where 65, 34, 17, 3 and 1
taxa belonged to Baciallriophyceae, Charophyceae, Cyanophyceae, Dinophyceae and both
Euglenophyceae and Cryptophyceae, respectively. Temporal and spatial variations in total number of
phytoplankton were noticed in this study. Highest total number was (2.42 cell x 103 /l) recorded at site 2 in
May 2013 and the lowest was (0.18 cell x 103 /l) recorded at site 4 in January 2013. Cyclotell, Aulacoseria,
Cocconeis, Cymatoplerura, Nitzschia, Cymbella and Oscillatoria were all recorded over study time.

Chaetognaths are important members of Arctic mesozooplankton communities in terms of abundance and biomass. Despite this, the bulk of seasonal studies have focused on grazing copepods. Arctic chaetognaths comprise three major species which are thought to be strict carnivores: Eukrohnia hamata, Parasagitta elegans and Pseudosagitta maxima. This thesis uses datasets collected from plankton net sampling during five years in European, Canadian and Alaskan areas of the Arctic (2007, 2008, 2012, 2013, 2014) and includes a full annual cycle in the Canadian Arctic (2007-2008), the purpose being to improve our understanding of the distributions, life history and feeding strategies of E. hamata and P. elegans. The following topics are addressed: (1) the feeding strategy and maturity of P. elegans in the European Arctic during the polar night in 2012 and 2013; (2) the growth, breeding cycles, feeding strategies and vertical distributions of E. hamata and P. elegans, in the Canadian Arctic from 2007 to 2008; and (3) spatial differences in the feeding strategies of E. hamata and P. elegans in autumn 2014. To investigate feeding strategies, a combination of gut contents and biochemical techniques was used. In the Canadian Arctic, both E. hamata and P. elegans live for around 2 years. P. elegans mainly colonized epi-pelagic waters, whereas E. hamata mainly colonized meso-pelagic waters. In this region, P. elegans reproduced continuously from summer to early winter when copepod prey peak in near-surface waters. This is characteristic of income breeders. However, results for E. hamata revealed that this species spawned distinct and traceable broods during separate reproductive windows in both spring-summer and autumn-winter, suggesting capital breeding. Daily predation rates inferred from gut content analyses appeared to be generally low in the two chaetognath species, though inferred predation rates in summer-autumn exceeded those in winter-spring. Feeding studies revealed that E. hamata consumed particulate organic matter (possibly falling marine snow) throughout the year but especially in the summer, whereas P. elegans did not feed in this way. High summer growth seems to be a characteristic of both these species. Growth during winter was highly restricted in P. elegans, to a lesser extent in E. hamata. In summary, differences in how lipids and marine snow are utilised by the two species could explain differences in their breeding cycles and seasonal growth patterns.

Recommendations and Outlook. Long-term monitoring is required for a better estimation of state and the conditions of Lake Skadar. Further studies on factors influencing the phyto-plankton community, especially zooplankton grazing and toxic substances, which were not included in this study, should be continued in the future to improve the efficiency of phyto-plankton usage in estimating the ecological and trophic conditions of Lake Skadar. Abstract Background, Aims and Scope. Phytoplankton, as a first step in trophic cascades of lakes, can be a good indicator of trophic states, considering that every environmental change affects this community and many species of this community are sensitive to changes, and that they response very quickly. In this study, we tried to assess and predict the trophic state of Lake Skadar according to phytoplankton data. Methods. Water samples were collected using Ruttner sampling bottle. Temperature, dissolved oxygen, ph, conductivity and transparence were measured in situ using portable equipment. Nutrients and chlorophyll a were measured using standard spec-trophotometric methods. A determination of phytoplankton species was performed using relevant keys and the counting of cells was performed using sedimentation methods. Results and Discussion. The species composition of Lake Skadar revealed 95 taxa, with Chlorophyceae and Bacillariophyceae being represented best. According to an average chlorophyll a concentration of 5.9 µg/l, Lake Skadar belongs to the meso-trophic level of the trophic scale. Developed prediction equation for chlorophyll a revealed a good prediction (R 2 =0.71) and the parameter Secchi depth was primarily correlated with chlorophyll a concentration. Trophic state indices derived from chlorophyll a and transparency, were close together, but both were below the phosphorous index. Values of trophic state indices rank the Lake Skadar as being mesotrophic. This study also showed that indices of diversity based on phytoplankton are weak indicators of trophic status and that they can well characterize only differences between assemblages and associations. According to calculated saprobic indices (ranging from 1.5 to 2.15), Lake Skadar is on betamesosaprobic level of saprobity, which means that it is moderately polluted with organic compounds. Conclusions. Total phosphorus is not the main limiting factor for the phytoplankton community in Lake Skadar. Disagreements between chlorophyll and the transparency index, on the one hand, and the total phosphorus index, on the other, suggest that the phytoplankton in Lake Skadar is probably limited by other factors than phosphorus, such as nitrogen, toxic substances or intense zooplankton grazing. According to the majority of investigated parameters and indices derived from phytoplankton data, Lake Skadar is mesotrophic, with tendencies toward eu-trophic levels during the summer period.

Biomass, diversity, composition and taxonomic structure of phytoplankton in the Pacific Ocean of Colombia were studied
during Pacific XXXIX-ERFEN XXXVII oceanographic survey. The operative plan of sampling was structured along 40 stations in the
Pacific Ocean of Colombia. Discrete sampling of phytoplankton was carried out by oblique trawling with standard phytoplankton
net (60μm) in the 25 biological stations. Furthermore, chlorophyll-a concentration at standard depth in each biological stations
were estimated by spectrophotometry technique. 126 morph species of phytoplankton, belong to 37 genera, were identified.
The Diatom’s genera: Chaetoceros, Coscinodiscus, Thalassionema, Bacteriastrum, Rhizosolenia, Ditylum, Skeletonema, Nitzschia and Pseudonitzschia, were the dominant, following by Dynoflagelate´s genera: Ceratium, Ornithocercus, Pyrophacus, Protoperidinium, Dinophysis, Ceratocorys, Gonyaulax, Podolampas and Amphisolenia. This last taxonomic group trend to increase their abundance in the oceanic zone. Chlorophyll-a concentration was homogenous in the study area, ranged between 11.37 mgm-2 to 38.05 mgm-2 (integrate from 50 to 0m). Moreover, two centers of high Chlo-a concentration were identified: zone in the northern sector of oceanic zone (station 75) and the other one in the northern sector of coastal zone (Station 12).  Diversity index of Shannon (H’) and richness of Hill’s numbers (N0 y N1) were higher in costal zone that oceanic zone