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Nutrient limitation of phytoplankton in five impoundments on the Manyame River, Zimbabwe
P Tendaupenyu
Water SA , 2012,
Abstract: Nutrient limitation was investigated in the Manyame lakes, namely, Harava Dam, Seke Dam, Lake Chivero, Lake Manyame and Bhiri Dam, during 2004-05. Selenestrum capricornutum was used as the test organism in one group of bioassays and the lakes’ natural phytoplankton population in the other. Nitrogen was indicated to be the primary limiting nutrient in Harava Dam, Seke Dam and Lake Manyame. Phosphorus was found to be the primary limiting nutrient in Bhiri Dam while no nutrient was indicated to be limiting the growth of phytoplankton in Lake Chivero; instead, light was implicated to be limiting the growth of phytoplankton. Harava Dam and Seke Dam showed signs of enrichment, relative to 1977, attributed to sewage discharge from expanding urban settlements in Ruwa and surrounding areas. Lake Chivero has remained much the same in the last 30 years and was indicated to be acting as a nutrient trap, since the dams downstream of it were not found to be as eutrophic. Lake Manyame, Seke Dam and Harava Dam were concluded to be mesotrophic, Bhiri Dam oligotrophic and Lake Chivero eutrophic.
Differential Response of High-Elevation Planktonic Bacterial Community Structure and Metabolism to Experimental Nutrient Enrichment  [PDF]
Craig E. Nelson,Craig A. Carlson
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018320
Abstract: Nutrient enrichment of high-elevation freshwater ecosystems by atmospheric deposition is increasing worldwide, and bacteria are a key conduit for the metabolism of organic matter in these oligotrophic environments. We conducted two distinct in situ microcosm experiments in a high-elevation lake (Emerald Lake, Sierra Nevada, California, USA) to evaluate responses in bacterioplankton growth, carbon utilization, and community structure to short-term enrichment by nitrate and phosphate. The first experiment, conducted just following ice-off, employed dark dilution culture to directly assess the impact of nutrients on bacterioplankton growth and consumption of terrigenous dissolved organic matter during snowmelt. The second experiment, conducted in transparent microcosms during autumn overturn, examined how bacterioplankton in unmanipulated microbial communities responded to nutrients concomitant with increasing phytoplankton-derived organic matter. In both experiments, phosphate enrichment (but not nitrate) caused significant increases in bacterioplankton growth, changed particulate organic stoichiometry, and induced shifts in bacterial community composition, including consistent declines in the relative abundance of Actinobacteria. The dark dilution culture showed a significant increase in dissolved organic carbon removal in response to phosphate enrichment. In transparent microcosms nutrient enrichment had no effect on concentrations of chlorophyll, carbon, or the fluorescence characteristics of dissolved organic matter, suggesting that bacterioplankton responses were independent of phytoplankton responses. These results demonstrate that bacterioplankton communities in unproductive high-elevation habitats can rapidly alter their taxonomic composition and metabolism in response to short-term phosphate enrichment. Our results reinforce the key role that phosphorus plays in oligotrophic lake ecosystems, clarify the nature of bacterioplankton nutrient limitation, and emphasize that evaluation of eutrophication in these habitats should incorporate heterotrophic microbial communities and processes.
Susceptibility of bacterioplankton to nutrient enrichment of oligotrophic and ultraoligotrophic lake waters  [cached]
Roberto BERTONI,Cristiana CALLIERI,Esteban BALSEIRO,Beatriz MODENUTTI
Journal of Limnology , 2008, DOI: 10.4081/jlimnol.2008.120
Abstract: We carried out laboratory experiments in one ultraoligotrophic pristine Andean lake (Lake Gutiérrez, Argentina) and in one subalpine lake that is now at the edge of the oligo- to mesotrophic condition (Lake Maggiore, Italy). Lake water was amended with phosphorus (+P), organic carbon (+C), alone or in combination (+CP), to test for short-term changes (48 hours) in bacteria activity and community structure (CARD FISH). Experiments were carried out in spring and summer. Results showed that bacterial production increased in the +CP treatment in both lakes, and in the +P treatment in the ultroligotrophic lake. In both lakes the bacterial activity increased more rapidly in summer (within 24 hours). Bacteria composition changed in both seasons in all the treatments. At the beginning of the experiments the subclass of β-Proteobacteria dominated both lakes, while γ-Proteobacteria showed higher percentage in spring in Lake Maggiore and in summer in Lake Gutiérrez. After incubation, in spring and in particular in the +CP treatment, we observed an increase in the relative importance of γ-Proteobacteria in both lakes, whereas in Lake Maggiore this group declined in the summer experiments following an increase in β-Proteobacteria. All our results indicate the different response of bacterioplankton in systems at the edges of the oligotrophic range.
Ecomicrobiology and microbial assimilative capacity of the oligotrophic Andean Lake Laja, Chile
KARRASCH,BERNHARD; WOELFL,STEFAN; URRUTIA,ROBERTO; GONZáLEZ,JENNY; VALDOVINOS,CLAUDIO; CID,HERNáN; PARRA,OSCAR;
Revista chilena de historia natural , 2011, DOI: 10.4067/S0716-078X2011000300010
Abstract: a strong socio-economic development pressure in south chile will more and more cause an impact to the present lakes and rivers. nevertheless, our knowledge concerning the ecological structure and the microbial self-purification capabilities of these lacustrine water bodies is scant but essential for a future sustainable development of land and water use. we studied lake laja, a lake already heavily impacted by water diversions for hydropower generation and irrigation. typical for the andean region lake laja is an oligotrophic water body, limited by nitrogen nutrients. only very low chlorophyll a and particulate organic carbon (poc) concentrations and a small abundance and biomass of bacteria (mainly ultramicrobacteria) and heterotrophic flagellates were encountered. weak trophic interrelations were derived from a high bacteria-to-heterotrophic flagellate ratio. for the ten investigated extracellular enzymes (alkaline phosphatase, leucine, arginine-, glycine and tyrosine-aminopeptidase, α-, β-d-glucosidase, α-, β-d-galactosidase, n-acetyl-β-d-glucosaminidase), with the exception of α-d-glucosidase, a broad range of organic matter degradation activities was proven. probably, due to the n-limitation, organic nitrogen hydrolysing extracellular enzymes reached activities on average of 45 % compared to other studies in oligotrophic waters. the possible effect of n-limitation on extracellular enzyme activities was more pronounced by cell specific extracellular enzymatic activity rates, which exceeded those of other oligotrophic water bodies on average by factor 2. the overall activities of all microbial extracellular enzymes studied proved to be dominated by the dissolved free external enzymes (up to 98 %) over the ectoenzymes which are associated with particulate organic matter (bacterial cell walls, particles, and aggregates). it is concluded that future socio-economic changes, dealing with watershed human intervention (accelerating inorganic and organic loads) as well a
Present status and changes of the phytoplankton community after invasion of Neosalanx taihuensis since 1982 in a deep oligotrophic plateau lake, Lake Fuxian in the subtropical China
ZHANG Xi,XIE Ping,CHEN Fei-zhou,LI Yan-ling,LI Si-xin,GUO Ni-chun,QIN Jian-hui,
ZHANG Xi
,XIE Ping,CHEN Fei-zhou,LI Yan-ling,LI Si-xin,GUO Ni-chun,QIN Jian-hui

环境科学学报(英文版) , 2005,
Abstract: Phytoplankton assemblages in the subtrophical oligotrophic Lake Fuxian, the second deepest lake in China, were investigated monthly from September 2002 to August 2003. A total of 113 species belonging to seven phyla were identified, among them, a filamentous green alga, Mougeotia sp., dominated almost throughout the study period and comprised most of the total phytoplankton biomass. Mougeotia sp. has made a substantial development during the past decades: it was absent in 1957, only occasionally present in 1983, increased substantially in 1993, and became predominant in 2002-2003. It is likely that natural invasion of the Taihu Lake noodlefish (Neosalanx taihuensis) has led to a change of dominant herbivorous zooplankton from small to large calanoid, which has increased grazing pressure on small edible algae, and thus has indirectly favored the development of the inedible filamentous Mougeotia sp.
Sensitivity of winter phytoplankton communities from Andean lakes to artificial ultraviolet-B radiation
HELBLING,E. WALTER; VILLAFA?E,VIRGINIA E.; BARBIERI,ELENA S.;
Revista chilena de historia natural , 2001, DOI: 10.4067/S0716-078X2001000200005
Abstract: during july of 1999 sampling was carried out in five andean lakes to determine the sensitivity of winter phytoplankton communities to ultraviolet-b radiation (uv-b, 280-320 nm). the studied lakes, moreno, el trébol, nahuel huapi, gutiérrez, and morenito, located in the patagonia region (41° s, 71° w, 800 m of altitude), had attenuation coefficients for uv-b that ranged from 0.36 m-1 (lake moreno) to 2.8 m-1 (lake morenito). the samples were inoculated with labeled carbon (nah14co3) and incubated in an illuminated chamber (uv-b = 0.35 w m-2, uv-a [320-400 nm] = 1.1 w m-2, and par [400-700 nm] = 10.8 w m-2) at 10 °c. the phytoplankton cells were exposed to uv radiation (280-400 nm) + par (quartz tubes), and to uv-a + par (quartz tubes covered with mylar-d). the total duration of the experiments was 4 h and two samples were taken from each treatment every hour. in lakes moreno, el trébol, nahuel huapi and gutiérrez, the photosynthetic inhibition increased linearly with uv-b doses, while in lake morenito just a slight relationship was observed. after receiving a dose of 1.25 kj m-2 (uv-b), phytoplankton from lake morenito had the highest cumulative photosynthetic inhibition (44 %), whereas in lakes moreno, el trébol, nahuel huapi and gutiérrez the inhibition was of 22, 11, 5, and 1 %, respectively. however, at the end of incubation period and after receiving doses of 5 kj m-2, the most inhibited phytoplankton cells were from lake moreno (70 %) and the most resistant (27 %) was that from lake gutiérrez. the kinetics of inhibition was different in each lake, and transparent lakes, with higher proportion of large cells, had higher inhibition rates. the results suggest that an increase in uv-b radiation (e.g., produced by a decrease in stratospheric ozone) would have a greater impact on microplankton from clear lakes, while pico- and nanoplankton from less transparent lakes will be less affected
Planktonic ciliates from an oligotrophic South Andean lake, Morenito Lake (Patagonia, Argentina)
MODENUTTI, B. E.;PéREZ, G. L.;
Brazilian Journal of Biology , 2001, DOI: 10.1590/S1519-69842001000300007
Abstract: in this contribution we have studied the planktonic ciliates from morenito lake, an oligotrophic lake situated in the south andes of argentina. six species that are new records for south america or argentina are described and illustrated. besides, population dynamics of the ciliate species were studied during a spring?summer period. strobilidium lacustris and balanion planctonicum were the most abundant species, showing a maximum in mid summer. paradileptus elephantinus was present all over the period while urotricha furcata was observed in late summer samples. strobilidium lacustris and s. humile were found to be occasional species during the studied period. the recorded ciliate assemblage with oligotrichs and prostomates as dominant indicate the oligotrophic condition of the lake.
ECOLOGY OF PHYTOPLANKTON WITH RELATION TO PHYSICO - CHEMICAL PARAMETERS OF BOTHALI (MENDHA) LAKE, GADCHIROLI (M.S.)
RAJENDRAV. TIJARE
Indian Streams Research Journal , 2013,
Abstract: Bothali – Mendha lake is located at 200 - 11' latitude and 800 – 04' longitude situated in rural area. The lake is old “Malgujari” Talav type, having an area of about 39.68 hectares. Seasonal variations in the population of phytoplankton in relation to physico-chemical parameters were studied for a period of two years (November 2003 to October 2005) in lake. In all 16 genera were recorded of which 06 belongs to Chlorophyceae, 04 to Basillariophyceae, 03 to Cynophyceae (Myxophyceae), and 01 to Euglenophyceae respectively. Among these four families of phytoplankton Chlorophyceae remains dominant throughout the study period. Phytoplankton species and physico-chemical parameters profiles indicate the lake is oligotrophic.
Ecomicrobiology and microbial assimilative capacity of the oligotrophic Andean Lake Laja, Chile Ecomicrobiología y capacidad asimilativa microbiana del lago oligotrófico andino Laja, Chile
BERNHARD KARRASCH,STEFAN WOELFL,ROBERTO URRUTIA,JENNY GONZáLEZ
Revista chilena de historia natural , 2011,
Abstract: A strong socio-economic development pressure in South Chile will more and more cause an impact to the present lakes and rivers. Nevertheless, our knowledge concerning the ecological structure and the microbial self-purification capabilities of these lacustrine water bodies is scant but essential for a future sustainable development of land and water use. We studied Lake Laja, a lake already heavily impacted by water diversions for hydropower generation and irrigation. Typical for the Andean region Lake Laja is an oligotrophic water body, limited by nitrogen nutrients. Only very low chlorophyll a and particulate organic carbon (POC) concentrations and a small abundance and biomass of bacteria (mainly ultramicrobacteria) and heterotrophic flagellates were encountered. Weak trophic interrelations were derived from a high bacteria-to-heterotrophic flagellate ratio. For the ten investigated extracellular enzymes (alkaline phosphatase, leucine, arginine-, glycine and tyrosine-aminopeptidase, α-, β-D-glucosidase, α-, β-D-galactosidase, N-acetyl-β-D-glucosaminidase), with the exception of α-D-glucosidase, a broad range of organic matter degradation activities was proven. Probably, due to the N-limitation, organic nitrogen hydrolysing extracellular enzymes reached activities on average of 45 % compared to other studies in oligotrophic waters. The possible effect of N-limitation on extracellular enzyme activities was more pronounced by cell specific extracellular enzymatic activity rates, which exceeded those of other oligotrophic water bodies on average by factor 2. The overall activities of all microbial extracellular enzymes studied proved to be dominated by the dissolved free external enzymes (up to 98 %) over the ectoenzymes which are associated with particulate organic matter (bacterial cell walls, particles, and aggregates). It is concluded that future socio-economic changes, dealing with watershed human intervention (accelerating inorganic and organic loads) as well as global change (temperature and precipitation changes) could lead to significant changes in the ecology of Lake Laja. La gran presión generada por el desarrollo socioeconómico del sur de Chile, está causando cada vez más un mayor impacto en los lagos y ríos allí presentes. Sin embargo, el conocimiento de la estructura ecológica y la capacidad microbiana de autodepuración de los cuerpos de agua lacustres es escasa, pero esencial para un futuro uso sostenible de los recursos agua y suelo. Se estudió el lago Laja, por ser un cuerpo de agua muy afectado por la extracción de agua para la generació
Planktonic ciliates from an oligotrophic South Andean lake, Morenito Lake (Patagonia, Argentina)  [cached]
MODENUTTI B. E.,PéREZ G. L.
Brazilian Journal of Biology , 2001,
Abstract: In this contribution we have studied the planktonic ciliates from Morenito Lake, an oligotrophic lake situated in the South Andes of Argentina. Six species that are new records for South America or Argentina are described and illustrated. Besides, population dynamics of the ciliate species were studied during a spring--summer period. Strobilidium lacustris and Balanion planctonicum were the most abundant species, showing a maximum in mid summer. Paradileptus elephantinus was present all over the period while Urotricha furcata was observed in late summer samples. Strobilidium lacustris and S. humile were found to be occasional species during the studied period. The recorded ciliate assemblage with oligotrichs and prostomates as dominant indicate the oligotrophic condition of the lake.
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