scholarly journals Cyanobacterial blooms in oligotrophic lakes: Shifting the high‐nutrient paradigm

2021 ◽  
Author(s):  
Kaitlin L. Reinl ◽  
Justin D. Brookes ◽  
Cayelan C. Carey ◽  
Ted D. Harris ◽  
Bas W. Ibelings ◽  
...  
Keyword(s):  
Cyanobacterial Blooms ◽  
Oligotrophic Lakes ◽  
High Nutrient

scholarly journals Thermocline depth and euphotic zone thickness regulate the abundance of diazotrophic cyanobacteria in Lake Tanganyika

2020 ◽  
Author(s):  
Benedikt Ehrenfels ◽  
Maciej Bartosiewicz ◽  
Athanasio S. Mbonde ◽  
Kathrin B. L. Baumann ◽  
Christian Dinkel ◽  
...  
Keyword(s):  
Phytoplankton Community ◽  
Lake Tanganyika ◽  
Ecological Factors ◽  
Euphotic Zone ◽  
Cyanobacterial Blooms ◽  
Thermocline Depth ◽  
Nitrogen Fixing ◽  
Multiple Observations ◽  
High Nutrient ◽  
Diazotrophic Cyanobacteria

Abstract. In spite of the fact that cyanobacterial blooms are classically associated with high nutrient loadings, there is also abundant evidence revealing that nitrogen fixing cyanobacteria (diazotrophs) can prevail under oligotrophic conditions. The mechanisms favouring diazotrophs in oligotrophic water bodies remain, however, poorly resolved. Here we analyse biogeochemical and ecological factors regulating the distribution of nitrogen fixing cyanobacteria in the oligotrophic Lake Tanganyika using sensor profiles of hydrodynamic conditions, nutrient and pigment analyses, as well as phytoplankton community assessment. During periods of stable or re-establishing water column stratification, we find evidence that the location of the thermocline and the euphotic depth can create a functional niche for diazotrophic cyanobacteria: Nitrogen limitation provides an ecological advantage for an apparent mutualistic interaction between diazotrophs and diatoms when the upward transport of nitrate into the euphotic zone is reduced by a subjacent thermocline. Diazotrophs, comprising the filamentous genera Dolichospermum and Anabaenopsis, are key players under these conditions (up to 41.7 % of phytoplankton community), while they are rare otherwise. By contrast, a thermocline located within the euphotic zone allows rapid vertical transport of nitrate for a thriving nitrate assimilating phytoplankton community that evidently outcompetes diazotrophs. Finally, multiple observations of relatively high diazotroph densities in the upwelling region in the South of Lake Tanganyika imply that they may additionally thrive under high nutrient conditions, when nitrogen is heavily deficient with respect to phosphorous. This study highlights that, under nitrogen deficient conditions, cyanobacterial blooms may form in response to reduced nutrient fluxes to the productive surface waters.

Influence of increased nutrient supply on Microcystis aeruginosa at cellular and proteomic levels

2020 ◽  
Vol 85 ◽  
pp. 47-58
Author(s):  
Y Jiang ◽  
Y Liu
Keyword(s):  
Microcystis Aeruginosa ◽  
Regulatory Protein ◽  
Acid Synthesis ◽  
Nutrient Supply ◽  
Nitrogen Supply ◽  
Nitrogen And Phosphorus ◽  
Comprehensive Description ◽  
Amino Acid Synthesis ◽  
High Nutrient ◽  
Proteomic Responses

Various studies have observed that increased nutrient supply promotes the growth of bloom-forming cyanobacteria, but only a limited number of studies have investigated the influence of increased nutrient supply on bloom-forming cyanobacteria at the proteomic level. We investigated the cellular and proteomic responses of Microcystis aeruginosa to elevated nitrogen and phosphorus supply. Increased supply of both nutrients significantly promoted the growth of M. aeruginosa and the synthesis of chlorophyll a, protein, and microcystins. The release of microcystins and the synthesis of polysaccharides negatively correlated with the growth of M. aeruginosa under high nutrient levels. Overexpressed proteins related to photosynthesis, and amino acid synthesis, were responsible for the stimulatory effects of increased nutrient supply in M. aeruginosa. Increased nitrogen supply directly promoted cyanobacterial growth by inducing the overexpression of the cell division regulatory protein FtsZ. NtcA, that regulates gene transcription related to both nitrogen assimilation and microcystin synthesis, was overexpressed under the high nitrogen condition, which consequently induced overexpression of 2 microcystin synthetases (McyC and McyF) and promoted microcystin synthesis. Elevated nitrogen supply induced the overexpression of proteins involved in gas vesicle organization (GvpC and GvpW), which may increase the buoyancy of M. aeruginosa. Increased phosphorus level indirectly affected growth and the synthesis of cellular substances in M. aeruginosa through the mediation of differentially expressed proteins related to carbon and phosphorus metabolism. This study provides a comprehensive description of changes in the proteome of M. aeruginosa in response to an increased supply of 2 key nutrients.

Estimation of the productivity and nutritionality of forage mass of new varieties of Medicago lupulina

2020 ◽  
Author(s):  
A.V. Vorsheva ◽  
◽  
G.V. Stepanova
Keyword(s):  
Vitamin D ◽  
Ascorbic Acid ◽  
Aerial Part ◽  
Nutrient Content ◽  
Calcium Salts ◽  
Green Mass ◽  
Medicago Lupulina ◽  
High Nutrient ◽  
New Varieties

Medicago has a high nutrient content, and the aerial part of Medicago lupulina contains saponins, tannins, estrogenic substances and calcium salts. The leaves of this plant contain carotene, vitamin D and ascorbic acid. Medicago lupulina can develop a significant green mass, has low pubescence, thin stems and provides a delicate forage. The article presents the results of assessing the productivity and feeding qualities of new varieties ofMedicago lupulina

THE COMPOSITION AND DISTRIBUTION OF BENTHIC FORAMINIFERA AT CORAL REEF ECOSYSTEM IN THOUSANDS ISLAND

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Lumban Nauli Lumban Toruan ◽  
Dedi Soedharma ◽  
Kresna Tri Dewi
Keyword(s):  
Coral Reef ◽  
Human Activities ◽  
Close Association ◽  
Mesh Size ◽  
Coral Reef Ecosystem ◽  
Composition Distribution ◽  
Benthic Foraminifers ◽  
High Nutrient ◽  
Binocular Microscope ◽  
Reef Ecosystem

Composition and distribution of foraminifers are affected by human activities and have close association with coral reef ecosystem. The aims of this research were to investigate the benthic foraminifers’ composition and distribution in sediment of coral reef ecosystem. Eleven stations of Karang Bongkok, Pramuka, and Onrust Island were observed in this study. The sediments were taken from surface substrate up to 2 cm under the substrate. Samples were washed on sieve with mesh size 0,063 mm, and then dried in oven with 50°C of temperature  for two hours. After separating from the sediment, the foraminifers were laid on foraminiferal slide and indentified using binocular microscope. The highest composition of symbiont-bearing foraminiferal assemblages which associated with reef ecosystem was in East Pramuka (78.17%) and the lowest was in South Onrust (21,83%). The opportunistic type had the highest composition in South Onrust (38.67%) and the lowest was in South Karang Bongkok. In west Pramuka had the highest composition of heterotrophic type (57.17%) and the lowest was in North Onrust (11.33%). Onrust Island was dominated by opportunistic type, indicating high nutrient. The highest amount of foraminifers’ taxa was found in Karang Bongkok with good coral reef coverage, while the lowest in Onrust facing with Jakarta Bay. Keywords: composition, distribution, benthic foraminifers, coral reef.

Comprehensive Surgical Management of Chronic Suppurative Osteomyelitis Extending to The Lower Border of Mandible – A Case Report

2018 ◽  
Vol 5 (3) ◽  
Author(s):  
Deepak Kaul ◽  
Farahnaz Muddebihal ◽  
Mohammed Anwar Ul Haque Chand
Keyword(s):  
Developing Countries ◽  
Case Report ◽  
Surgical Treatment ◽  
Surgical Management ◽  
Surgical Debridement ◽  
Reconstruction Plate ◽  
Left Posterior ◽  
High Nutrient ◽  
Inferior Border ◽  
Precipitating Factor

Osteomyelitis of maxillofacial skeleton is common in developing countries such as India. This case report describes successful surgical treatment of chronic suppurative osteomyelitis {CSO} of the mandible of a 35yr old female. The precipitating factor was thought to be eventful extraction in the {left } posterior body at the inferior border of mandible. Methods: Presurgical course of antibiotics ( Amoxycillin and metronidazole for 7 days and later followed by doxycycline for 1 month).Surgical debridement of the affected bone and reinforcing it with reconstruction plate using AO principles was done . Patient was kept on a high nutrient diet consisting of proteins. Conclusion: The case report demonstrates the typical features of CSO . The combination of the antibiotics therapy and surgical debridement was successful in the treatment of chronic suppurative osteomylitis.

Nutrient Input and Trophic Status of the “Neue Donau”, a High-Water Control System along the River Danube in Vienna, Austria

1990 ◽  
Vol 22 (5) ◽  
pp. 137-144 ◽  
Author(s):  
M. T. Dokulil ◽  
G. A. Janauer
Keyword(s):  
Water Quality ◽  
Control System ◽  
Trophic Status ◽  
High Water ◽  
Nutrient Concentrations ◽  
Nutrient Input ◽  
Water Control ◽  
Trophic Conditions ◽  
River Danube ◽  
High Nutrient

The system “Neue Donau” functions as a control system for high waters of the river Danube and is an important recreational area for many people. Water quality and trophic status of the water body is thereforeof prime importance. The high nutrient concentrations of the river Danube (P-tot 238±41µg/l, N-tot 2.53±0.78 mg/l) reach the system via groundwater seepage. Present conditions in the basin of Neue Donau are,as a result of this nutrient in-flux,eutrophic to hypertrophic. Average values during the summer period have declined from 366 µg/l total phosphorus to 78 µg/l, and from 86 µg/l chlorophyll-a tol7µg/l between the years 1985 and 1988. However, a dam which is planned in the river at Vienna will permanently raise the water level of the river thus increasing the the groundwater flow in the direction to the Neue Donau and therefore the nutrient input which will enhance trophic conditions in the impoundment. Since macrophytes play an important role in one part of the system macrophyte management together with measures along the river are some of the suggested strategies to keep the system Neue Donau at acceptable trophic conditions and good water quality.

Long-term changes in fish pond management as ‘an unplanned ecosystem experiment’: importance of zooplankton structure, nutrients and light for species composition of cyanobacterial blooms

1995 ◽  
Vol 32 (4) ◽  
pp. 187-196 ◽  
Author(s):  
L. Pechar
Keyword(s):  
Species Composition ◽  
Fishery Management ◽  
Grazing Pressure ◽  
Organic Fertilizers ◽  
Cyanobacterial Blooms ◽  
Fish Stock ◽  
Fish Ponds ◽  
Single Filament ◽  
The 1950S ◽  
Water Blooms

The study presents data on the species composition of cyanobacterial water blooms in Czech fish ponds from the 1950s to the 1990s. Since the 1950s, a shift from large-colonial Aphanizomenon flos-aquae var. flos-aquae through Microcystis aeruginosa and small-colonial species of Anabaena to single-filament species (Planktohrix agardhii, Limnothrix redekei, Aphanizomenon gracile) or single-cell forms (Microcystis ichtyoblabe), has been observed. The changes in the species composition of the water blooms are closely related to changes in fishery management (increase in fish stock, increase in application of organic fertilizers). At present the high predation of fish upon zooplankton results in elimination of large colonial blooms of A. flos-aquae associated with large filtering zooplankton (Daphnia). Low grazing pressure of zooplankton, low light conditions and low N:P ratios are suitable conditions for mass development of the small species of cyanobacteria. High pH is not necessary to achieve cyanobacteria dominance.

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