Cyanobacterial dominance: The role of buoyancy regulation in dynamic lake environments

Reynolds, C. S.; Oliver, Rod L.; Walsby, A. E.

doi:10.1080/00288330.1987.9516234

Cited by 396 publications

(225 citation statements)

References 45 publications

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“…Some members of the cyanobacteria are able to make vertical movements by regulating their buoyancy within the water column through intracellular gas vacuoles (Walsby, 1969). This mechanism gives this group the advantage of relocating themselves at the optimal depth within a stable water column to obtain solar radiation in surface water in daytime and absorb sufficient nutrients in bottom layer at night (Walsby and Booker, 1980;Reynolds et al, 1987;Xiao et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China

Pan

et al. 2014

Journal of Environmental Sciences

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a b s t r a c tSpatial variations in phytoplankton community within a large mesotrophic reservoir (Miyun reservoir, North China) were investigated in relation to variations in physico-chemical properties, nutrient concentrations, temperature and light conditions over a 5 month period in 2009. The dynamics of phytoplankton community was represented by the dominance of cyanobacteria through summer and fall, following with a short term dominance of chlorophyta in late fall, and a relatively high abundance of diatom in October; on the other hand, maximum phytoplankton biomass was recorded in the north shallow region of Miyun reservoir with a higher nutrients level. Particular attention was paid to the impacts of environmental conditions on the growth of two cyanobacteria genera, the toxin-producing Microcystis and the taste & odor-producing Oscillatoria. Microcystis biomass was in general greatly affected by water temperature and mixing depth/local water depth ratio in this reservoir, while the Oscillatoria biomass in the surface and middle layers was greatly affected by total dissolved phosphorus, and that in the bottom layer was related with the Secchi depth/local water depth ratio. Abundant Oscillatoria biomass was observed only in late September when Microcystis biomass decreased and allowed sufficient light go through.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China

Pan

et al. 2014

Journal of Environmental Sciences

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“…In order to keep the buoyant Microcystis in suspension, the artificial mixing velocity should exceed the flotation velocity of the cyanobacterium . The mixing velocity needs to be rather high as the maximal vertical velocity of Microcystis can be as high as 2 .6 m h-1 (Visser, 1995) ; 8 .3 m h-1 (Humphries & Lyne, 1988) or 10 .8 m h -1 (Reynolds et al ., 1987) . This variety of velocities mainly results from differences in the radius of the colonies .…”

Section: Introductionmentioning

confidence: 99%

Diurnal buoyancy changes of Microcystis in an artificially mixed storage reservoir

Visser

Ketelaars²,

Breemen³

et al. 1996

Hydrobiologia

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Key words : buoyancy, artificial mixing, aeration, Microcystis, cyanobacteria Abstract In a storage reservoir, which is artificially mixed in order to reduce algal and especially cyanobacterial growth, the cyanobacterium Microcystis is still present . The aim of the research was to investigate why Microcystis was able to grow in the artificially mixed reservoir . From the results it could be concluded that the large shallow area in the reservoir allows this growth . The loss of buoyancy during the day was much higher in this shallow part than in the deep part. Assuming that the loss of buoyancy was the result of a higher carbohydrate content, a higher growth rate in the shallow part may be expected . A higher received light dose by the phytoplankton in the shallow mixed part of the reservoir than in the deep mixed part explains the difference in buoyancy loss . A significant correlation between the received light dose (calculated for homogeneously mixed phytoplankton) and the buoyancy loss was found . Apparently, the Microcystis colonies were entrained in the turbulent flow in both the shallow and the deep part of the reservoir. With a little higher stability on one sampling day, due to the late start of the artificial mixing, the loss of buoyancy at the deep site was higher than on the other days and almost comparable to the loss at the shallow site . Although the vertical biomass distribution and the temperature profiles showed homogeneous mixing, the colonies in the upper layers apparently received a higher light dose than those deeper in the water column . Determination of the buoyancy state of cyanobacteria appeared to be a valuable method to investigate the light history and hence their entrainment in the turbulent flow in the water column .

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“…Gas-vacuolate cyanobacteria such as M. aeruginosa have the ability to regulate their buoyancy in response to light and nutrition (Reynolds et al, 1987;Oliver, 1994;Brookes and Ganf, 2001). When cultivated in the laboratory with equal light and nutrition conditions, M. aeruginosa do not need to regulate buoyancy by gas vesicle to obtain more light or nutrition.…”

Section: Discussionmentioning

confidence: 99%

Benefits and costs of the grazer-induced colony formation inMicrocystis aeruginosa

Yang

Kong

Yang

et al. 2009

Ann. Limnol. - Int. J. Lim.

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-Colonial Microcystis aeruginosa were obtained when the unicellular algae were exposed to flagellate Ochromonas sp. filtrate. To investigate the benefit of this morphological change, flagellates were added into cultures of unicellular and colonial M. aeruginosa, respectively. The clearance rates of flagellates on algae were markedly decreased when they were cultivated with induced colonial M. aeruginosa. This result indicated that colony formation in M. aeruginosa was a predator-induced defense, which could reduce predation risk from flagellate. The increased content of soluble extracellular polysaccharide (sEPS) and bound extracellular polysaccharide (bEPS) may play an important role in adhering M. aeruginosa cells together to form colonies. The decrease of WPS II and the increase of sinking rates of induced colonial M. aeruginosa showed that the costs of grazed-induced colony formation in M. aeruginosa may reflect in the photosystem II efficiency, and in the sinking rates.

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Cyanobacterial dominance: The role of buoyancy regulation in dynamic lake environments

Cited by 396 publications

References 45 publications

Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China

Spatial and temporal variations of two cyanobacteria in the mesotrophic Miyun reservoir, China

Diurnal buoyancy changes of Microcystis in an artificially mixed storage reservoir

Benefits and costs of the grazer-induced colony formation inMicrocystis aeruginosa

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