Planktonic Research Articles

Planktonic predation risk: effects of diel state, season and prey life history stage

Fil: Kerr, Kecia A.. Mc Gill University; Canada. Instituto Smithsonian de Investigaciones Tropicales; Panama

Rotifer assemblages (Rotifera: Eurotatoria) of the floodplain lakes of Majuli River Island, the Brahmaputra river basin, northeast India

Our plankton and semi-plankton collections from twelve floodplain lakes (beels) of Majuli River Island, Upper Assam reveal 124 rotifer species (32 genera and 17 families); these merit biodiversity value as ~52.0% and ~30.0% of species, ~68.0 and ~45.0% of genera and ~74.0 and ~65.0% of the families of the Phylum known from northeast India (NEI) and India, respectively. Two species are new to India with Trichocerca uncinata as new record to the Oriental region. Eleven species are new to the study area and we provide an updated list (144 species) for following meta-analyses of Majuli Rotifera. Biogeographically important elements include one Australasian, four Oriental, four Palaeotropical and one cosmo (sub) tropical species while several species are of regional distribution interest. The rotifer fauna is predominantly tropical and Lecanidae > Lepadellidae collectively include ~53.0% species but it records paucity of Brachionus species. Individual beels record total richness of 60-100 (77 ± 12) species, monthly richness between 24 ± 7-34 ± 7 species and maximum up to 54 species/sample. The results are characterized by high community similarities (59.7-90.4% vide Sorensen’s index), more rotifer homogeneity amongst beels, lack of any pattern of temporal richness variations and much limited influence of abiotic parameters.

The use of planktons as tools for monitoring water quality in oil polluted streams of the Niger Delta, Nigeria

The Niger Delta ecosystems of Nigeria, typically consisting of mangrove swamps and riparian forests, have come under threat in the last six decades as a result of environmental pollution from oil exploration, drilling, refining and transportation. This study examines two Niger Delta streams (Ogba Evie and Otor) to ascertain the extent of hydrocarbon and heavy metal pollution and the status of the biotic communities in them. The physicochemical parameters of surface water samples indicate that dissolved oxygen is significantly lower in Ogba Evie stream which had some of its surface covered with oil films compared to Otor stream. Oil and grease levels were, however, well within the National Environmental Standards and Regulation Enforcement Agency (NESREA) safety limits. Both streams had high concentrations of polycyclic aromatic hydrocarbons (PAHs) and several heavy metals. Overall, the diversity indices point to low phytoplankton and zooplankton species diversity and abundance. Phacus curvicauda Swirenko was the most abundant phytoplankton in the Ogba Evie stream, while Synedra ulna (Nitzsch) Ehrenberg was predominant at the Otor stream. The copepod, Cyclops strenuus Fisher was the most abundant zooplankton common to all sections of both streams. Although, no significant relationship was observed between PAH and plankton abundance, the trend observed in both streams may be a reflection of their present-day pollution rates.

Phytoplankton composition and water chemistry of a tidal creek (Ipa-Itako) part of Lagos Lagoon

The composition and diversity of planktonic algae in a sluggish tidal freshwater/brackish mangrove dominated creek (Ipa Itako) part of the Lagos lagoon was investigated for twelve months (February 2010 - January 2011). The surface water pH varied between 6.5 (December 2010) and 8.6 (August 2010) indicating a slightly acidic to alkaline nature of the creek. The salinity was higher during the dry months (November- April) and phosphate - phosphorus and nitrate-nitrogen recorded highest values (3.50 and 16.70 mg/L) respectively in June, 2010. Ninety three species belonging to forty nine genera from five classes (Bacillariophyceae, Chlorophyceae, Euglenophyceae, Cyanophyceae and Xanthophyceae) were recorded. Bacillariophyceae constituted the most abundant group making up 72.85% of cells/ml followed by the Chlorophytes (18.02%) then the blue green (7.65%), euglenoids (1.40%) and xanthophytes (0.07%) with only Vaucheria sp. recorded as a representative of the group. Higher phytoplankton diversity and cell counts were recorded in the dry months than in the wet months. Navicula, Pinnularia, Cymbella (Diatoms) and Closterium (Chlorophyceae) were more frequently occurring species. Community structure analysis indices used indicated a diverse but stressed environment. Key words: Diversity, phytoplankton, creek, eutrophication.

Attention to the antibiotic resistance caused by bacterial biofilm and its solutions

Biofilm formation makes bacteria adopt a multicellular lifestyle.Compared to planktonic cells, biofilm-grown cells express an increased resistance to antimicrobial agents.Bacterial biofilm formation is a crucial step in the pathogenesis of many subacute and chronic bacterial infections.In clinical setting, biofilm can cause bacterial biofilm disease and biomaterial associated infection.Understanding the mechanisms involved in biofilm-associated antimicrobial resistance is key to the development of new solutions.（Chin J Lab Med,2014,37:725-727） Key words: Bacteria; Biofilms; Drug resistance, bacterial; Clinical protocols

First report of Colacium vesiculosum Ehrenberg 1853 (Euglenophyceae), as epibiont on planktonic copepods (Crustacea, Copepoda), in a Brazilian floodplain lake

Epibiosis is a facultative association between two organisms: the epibiont, which colonizes the surface of living substrates, and the basibiont, which hosts the epibionts. Among protists, while numerous accounts exist for ciliates as epibionts of zooplankton, little information is available about the occurrence of this relationship between flagellates and microcrustaceans in the neotropics. During a survey on the epibiotic relationship between ciliated protists and planktonic copepods in a tropical floodplain, we reported for the first time the occurrence of Colacium vesiculosum as an epibiont on Thermocyclops minutus and Notodiaptomus amazonicus from southern Brazil. The mean infestation prevalence was significantly higher on adults 30.53% (± 2.85) in comparison with copepodites 0.87% (± 0.55). When hosts were separated by order (Calanoida and Cyclopoida) copepodites presented a mean infestation prevalence of 0.92% (± 0.85) and 0.83% (± 0.60) respectively, while adults had a mean prevalence of 29.55% (± 6.8) and 30.13% (± 5.83), which could be explained by the fact that adult copepods provide a more stable substrate for epibionts.

Automated Marine Plankton Image Techniques and Its Application

Automated Marine Plankton Image Techniques and Its Application

Criptógamos do Parque Estadual das Fontes do Ipiranga, São Paulo, SP. Algas 36: Bacillariophyceae (Cymbellales)

Foi providenciado o levantamento florístico da ordem Cymbellales (Bacillariophyceae) na área do PEFI, Parque Estadual das Fontes do Ipiranga, São Paulo, SP, Brasil, com base na análise de 28 unidades amostrais. Amostras de plâncton foram obtidas com auxílio de rede e as de perifíton pela coleta e remoção das diatomáceas aderidas aos talos de macrófitas aquáticas submersas. O material foi oxidado e analisado em microscopia de luz e eletrônica de varredura. Seis gêneros e o total de 36 táxons foram identificados. Características morfológicas e dimensões das frústulas foram providenciadas para todos os táxons registrados. Das espécies identificadas, as seguintes 13 são novos registros para o PEFI: Cymbella tropica, C. turgidula var. venezoelana, Encyonema neogracile var. tenuipunctata, E. angustecapitatum, E. cf. brevicapitatum, Placoneis constans var. symmetrica, P. hambergii, P. undulata, Gomphonema parvulum var. exilissimum, G. augur var. turris, G. brasiliense subsp. pacificum, G. laticollum e G. urugayense.

Response of Freshwater Bloom-Forming Planktonic Cyanobacteria to Global Warming and Nutrient Increase

Abstract Savadova K., 2014: Response of freshwater bloom-forming planktonic cyanobacteria to global warming and nutrient increase [Planktoninių melsvabakterių atsakas į globalinį atšilimą ir maistmedžiagių kiekio padidėjimą gėluose vandens telkiniuose ]. - Bot. Lith., 20(1): 57-63. Human activities stimulate changes in aquatic environment, promoting temperature rise and eutrophication. Disturbance in aquatic ecosystems lead to alterations in plankton communities and food web structure. Cyanobacteria, which are able to regulate their buoyancy, are adapted to low-light, high temperatures, are capable to store phosphorus and fix nitrogen, produce toxins, which help to acquire competitive traits over other phytoplankton species. So, increasing temperature and loadings of nutrients in lakes stimulate successful proliferation of cyanobacteria and heavy bloom formation. Usually higher temperature (> 20ºC) and lower N:P mass ratio determine the dominance of cyanobacteria species in lakes and this is expected to increase in the future

'Extinct' plankton found in Pacific

'Extinct' plankton found in Pacific

赤潮过程中“藻-菌”关系的研究进展

微生物对促进海洋物质循环，维持水生环境的生态平衡具有重要作用。在赤潮事件中，基于微生物（尤其是细菌）的多样性和重要性，它们与藻类之间的相互关系成为了研究的热点。过去20年里，人们从不同角度对“藻-菌”间的关系进行了探索，包括物理学过程、生物学过程、环境过程以及化学过程。就化学过程而言，它作为一种较早出现的技术，在以往的研究中带给人们许多认识藻菌关系的方法。随着学科的渗透，化学法有了拓展与延伸，为人们认识藻菌关系带来了新的契机。从化学生态学领域来梳理“藻．菌”关系中涉及的现象和行为，包括菌对藻的有益面、菌对藻的有害面、以及藻类应答细菌行为的化学途径；并从信号语言（群体感应、化感作用）的角度来阐释两者之间的互生或克生关系。通过文献综述的方式来解读藻菌关系的互作过程和机理，为认识赤潮的发生和防控方法提供借鉴。

Cyanoprokaryota in Plankton of the Rivers and Lakes of Omsk Priirtyshye (Russia)

Cyanoprokaryota in Plankton of the Rivers and Lakes of Omsk Priirtyshye (Russia)

Phylogenetic Analysis of Thermocyclops decipiens with Reference to 18S rDNA

Many ecological studies on the diversity and distribution of freshwater planktonic cyclopoid copepods are being published and they depend upon the molecular methods for accurate taxonomic identification. The greater coverage of reference species in the genetic database, GenBank, with the decreasing costs for DNA sequencing, have made large scale plankton identification studies using molecular methods, more feasible. Here, we present a practical molecular approach to identify Thermocyclops decipiens , collected from Karapakkam Temple tank, Chennai, India. Molecular identification methods of cyclopoids included amplification of 18S rDNA. The present work on molecular phylogenetic analysis of freshwater cyclopoid copepods deals with the evolutionary relation among 12 species of freshwater cyclopoid copepods. The 18S rDNA sequences were analyzed using ClustalW, Maximum Likelihood method, Distance method and UPGMA method. The Multiple Sequences Alignment showed less score value of 52 between Thermocylops decipiens and Mesocyclops thermocyclopoides . Among 12 species of freshwater cyclopoid copepods, Mesocyclops edax and Mesocyclops darwini were single phyletic group in UPGMA method. By Maximum Likelihood analysis of Mesocyclopos thermocyclopoides , confident limit was 1.9870–7.30265 with positively significant at p<0.05 level and the distance compared with other species was 4.643516–5.873569.

PLANKTON COMMUNITY, WATER QUALITY AND GROWTH PERFORMANCE OF NILE TILAPIA AS AFFECTED BY HUMIC ACID IN AQUACULTURE PONDS

PLANKTON COMMUNITY, WATER QUALITY AND GROWTH PERFORMANCE OF NILE TILAPIA AS AFFECTED BY HUMIC ACID IN AQUACULTURE PONDS

The Vertical Distribution of Micro- and Small Mesozooplankton in the Central Red Sea

AbstractThe abundance and taxonomic composition of plankton sampled with nets of 0.1 mm mesh size were determined at the Atlantis II Deep, central Red Sea, in October and November 1980, from the surface to a depth of 1650 m. The fine mesh nets yielded three times as much total plankton biomass and thirty times the number of metazoan organisms compared to what was collected during earlier investigations using nets with a larger, 0.3 mm mesh size. The patterns of vertical distribution, determined by using the two different mesh sizes, were similar with respect to the gradients of plankton abundance but different with regard to the relative proportions of species and higher taxa. When the smaller metazoans were included by the use of fine mesh nets, cyclopoid copepodids became more numerous than the calanoid copepodids in all depth layers sampled, and their relative importance increased with depth. Between 200 m and 1050 m depth, over 50% of all copepodids belonged to the cyclopoid genus Oncaea. A review of ...

Distephanus/Dictyocha Ratios and Seawater Temperature (Cl.: Mastigophorea, Order: Silicoflagellida)

AbstractThe ratio in abundance of the two silicoflagellate genera Distephanus and Dictyocha in sediment and plankton samples has been used to identify seawater temperature: over a range of 0° to 30°C the ratio should shift from 100% Distephanus to 100% Dictyocha. Studies of plankton samples showed that this shift is found in the South Atlantic but not in the North Atlantic. Near 11°C in the North Atlantic the ratio rather abruptly reverses, which points to a different temperature sensitivity in the north and the south. The findings indicate that the relation between sea-surface temperature and Distephanus/Dictyocha ratio is different in the four seasons of the year and in different geographic areas.

Paradox of the phytoplankton―an overview

AbstractThis article reviews some of the literature which has contributed to our knowledge of the paradox of the plankton, a paradox originally proposed by Hutchinson (1961). I first examine the ecology of the phytoplankton with particular reference to the question of whether or not competition for a limited amount of nutrient occurs among aquatic unicellular algae. Here I include original data, which is of value to an examination of the idea of carbon as a limiting nutrient, at least to control of the higher taxonomic composition of phytoplankton. I second examine the evolution of the phytoplankton, for which we have little information, and conclude that it is time to learn more about the fundamental biology including the genetics and evolution of the algae composing the phytoplankton. Throughout this review, I freely comment on potential research endeavors, which I believe may enhance our knowledge of the ecology and evolution of the phytoplankton.

Stock Assessment by Larval Surveys of the Winter Population of Todarodes pacificus Steenstrup (Cephalopoda: Ommastrephidae), with a Review of Early Works

This is a study of larval abundance and distributional pattern of the winter population of the Japanese common squid, Todarodes pacificus Steenstrup, based on plankton net collections made by the R...

Mortality in the Ocean-With Lessons from Hydrothermal Vents off Kueishan Tao, Ne-Taiwan

There is evidence of plankton mortality and extinction at various temporal and spatial scales induced by man-made pollution, or by natural causes (ageing, competition, predation, diseases, natural pollution). If mortalities take place at large scale they might become of environmental concern and may impact other biotic compartments including fisheries substantially. Such mortalities are a consistent phenomenon at time scales from geological mass extinctions to regularly occurring HABs, that appear to be increasing on a global basis. Several mass mortalities might have escaped our notice for their patchy and erratic occurrences. This also holds for mortalities caused by hydrothermal vents (HVs) that cover possibly more than 1.5% of the ocean floor. We studied zooplankton diversity, abundance and distribution patterns above shallow water hydrothermal vents at Kueishan Tao (Turtle Island), off the northeast coast of Taiwan (West Pacific). The HVs at this side provide an opportunity for the study of mortality, community and population effects of HV effluents with ecophysiological investigations that are otherwise difficult to perform at the more common HV environment, the deep sea. We found evidence for a bottle-neck situation for plankton above vent sites since holoplankton was generally deadly affected when immersed directly in vent plumes. Here we used copepods from HV sites for ecotoxicological testing in mesocosm field experiments.

Corrigendum to &amp;quot;Biogeography of planktonic bacterial communities across the whole Mediterranean Sea&amp;quot; published in Ocean Sci., 9, 585–595, 2013

Corrigendum to &amp;quot;Biogeography of planktonic bacterial communities across the whole Mediterranean Sea&amp;quot; published in Ocean Sci., 9, 585–595, 2013