Spatial heterogeneity of the dominant cyanobacteria in the surface waters of Lake Rotongaio

Horne, Alexander J.; Commins, Marcie L.

doi:10.1080/00288330.1987.9516251

Cited by 2 publications

(1 citation statement)

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“…Prior to HOS, Aphanizomenon counts for individual samples often exceeded 300 million cells/L, but a month later the same site would only record a few hundred cells per liter. Counts of buoyant colonial cyanobacteria are often erratic from week to week or month to month, reflecting natural fluctuations and spatial heterogeneity (Sandusky and Horne 1978, Horne and Commins 1987, McDonald and Lehman 2013. Algae sampling began before nutrient measurements and, measured as the average cell count per collection in the growth season (Apr-Oct), Aphanizomenon prior to HOS (1988HOS ( -1992 averaged 3.7 million cells/L but fell more than 95% to 363 cells/L after HOS (Aug 1993-May 1994).…”

Section: Changes In Phytoplankton and Zooplanktonmentioning

confidence: 99%

Hypolimnetic oxygenation 3: an engineered switch from eutrophic to a meso-/oligotrophic state in a California reservoir

Horne

Beutel

2019

Lake and Reservoir Management

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A long-term improvement in water quality due to a hypolimnetic oxygenation system (HOS) used without other management actions was shown for Camanche Reservoir in California (volume ¼ 514 million m 3). Prior to oxygenation, the reservoir was eutrophic with low water clarity, high chlorophyll a (Chl-a), and blooms of cyanobacteria primarily caused by internal nutrient loading from anoxic sediments. All 4 trophic state indicators showed major improvement, most pointing to a new oligotrophic state. Days after HOS startup in July 1993, hypolimnion soluble phosphate and ammonium concentrations declined and, unexpectedly, nitrate remained low. This report covers pre-HOS (1988 to mid-1993) and 12 yr of post-HOS measurements (mid-1993 to mid-2005). For surface waters during the growth season (Apr-Oct) after HOS, average Chl-a decreased 79% (14.6-3.1 lg/L) and peak Chl-a decreased sixfold (from 49 to 8 lg/L). Average Secchi depth increased 10-fold (0.47 to 4.9 m) and peak Secchi depth doubled (4.2-8 m). Cyanobacteria (Aphanizomenon and Dolichospermum, formerly Anabaena) decreased >95% while the previously absent Merismopedia, an indicator of clean water, appeared. The large colonial diatom Fragilaria also decreased by >90%. Zooplankton (rotifers and crustaceans) appeared unchanged. After HOS, late winter surface nutrients prior to the next spring bloom were much reduced (total phosphorus, TP, by 58%, total inorganic nitrogen, TIN, by 88%). The TIN:TP ratio dropped from 6 to 1.6. In 2004, the last full year of measurements, further declines were found for nitrate nitrogen (42-3 lg/L) and Chl-a (3.1-2.8 lg/L) while TP was unchanged (14 lg/L).

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Section: Changes In Phytoplankton and Zooplanktonmentioning

confidence: 99%

Hypolimnetic oxygenation 3: an engineered switch from eutrophic to a meso-/oligotrophic state in a California reservoir

Horne

Beutel

2019

Lake and Reservoir Management

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Spatial and temporal variability in filament length of a toxic cyanobacterium (Anabaena affinis)

Smith¹,

Gilbert²

1995

Freshwater Biology

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1. This study examines the distribution of Anabaena affinis filament lengths under natural conditions as a function of depth and season, and in the laboratory as a function of growth phase. Because Anabaena affinis is only toxic when consumed, both its filament length and position in the water column are important determinants of its potential impact on zooplankton populations. 2. Star Lake (Norwich, Vermont, U.S.A.), a natural, eutrophic pond, remained thermally stratified throughout the Anabaena bloom. Filament number and length differed significantly with both sampling date and water depth. Most filaments occurred at 0.5 m, particularly at the height of the bloom. Throughout the entire water colunm average filament length decreased from approximately 0.53 mm in May to 0.14 mm in July. The shortest filaments occurred at the 2.5 m depth. Filament length distributions (combined for all depths) for 29 May, 12 June and 3 July, corresponding to the beginning, middle and end of the bloom, respectively, differed significantly among the three dates. These patterns most likely reflect variable growth conditions, both during the season and in the water colunon. 3. In the laboratory, Anabaena filament length was affected by medium composition and growth phase. Filaments were significantly longer when grown in MBL than in ASM medium. Also, the average length of Anabaena filaments grown in MBL changed significantly as cultures aged; by day 13 filament length (2.01 ± 0.38 mm, mean ± SD) was twice that on day 0 (0.97 ± 0.71 mm). As cell concentration continued to increase, mean filament length gradually decreased.

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Spatial heterogeneity of the dominant cyanobacteria in the surface waters of Lake Rotongaio

Cited by 2 publications

References 0 publications

Hypolimnetic oxygenation 3: an engineered switch from eutrophic to a meso-/oligotrophic state in a California reservoir

Hypolimnetic oxygenation 3: an engineered switch from eutrophic to a meso-/oligotrophic state in a California reservoir

Spatial and temporal variability in filament length of a toxic cyanobacterium (Anabaena affinis)

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