Bacterioplankton in a small polyhumic lake with an anoxic hypolimnion

In the anoxic hypolimnion of Lake 227, Experimental Lakes Area, northwestern Ontario, ΣH2S exhibits a mid-depth maximum, while Fe2+ increases with depth. At the mid-depth ΣH2S maximum and below, saturation with respect to amorphous FeS is reached, and the concentration of ΣH2S is limited by the high Fe2+ concentrations, in accord with the FeS solubility product. Values for pKsp[Formula: see text] for FeS determined from the ΣH2S maximum and below averaged 3.16 in 1979 and agree well with other in situ and laboratory measurements. In the top 10 cm of sediment, pore water ΣH2S and Fe2+ are in equilibrium with amorphous FeS. Analyses of cores confirms the existence of an iron sulfide phase. Fe2+, which is produced in the pore water from the decomposition of organic matter, increases to concentrations at which siderite may form, although the presence of siderite has not been verified. Comparison of calculated pore water fluxes of Fe2+ with the observed increase of Fe2+ in the anoxic hypolimnion reveals that about 90% of the observed flux originates at the sediment–water interface, while the remainder is derived from pore water flux.

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Hypolimnion Injection of Nutrient Effluents as a Method for Reducing Eutrophication

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-045 ◽

1980 ◽

Vol 37 (3) ◽

pp. 320-327 ◽

Cited By ~ 28

Author(s):

D. W. Schindler ◽

T. Ruszczynski ◽

E. J. Fee

Keyword(s):

Surface Waters ◽

Standing Crop ◽

Nutrient Concentrations ◽

Precambrian Shield ◽

Water Interaction ◽

Anoxic Hypolimnion ◽

Long Term Trends

Injection of nutrients into the anoxic hypolimnion of a small Precambrian Shield lake for 5 yr caused less of a eutrophication problem than discharging nutrients into surface waters. Phytoplankton standing crop and production in the whole lake averaged only 10–21% of values in a nearby lake fertilized at the surface. Five-year averages for the epilimnion only were still lower: 5–8% of those in the surface-fertilized lake. Analysis of long-term trends in chlorophyll and nutrient concentrations revealed much slower rates of increase than in surface-fertilized lakes.Key words: eutrophication, hypolimnion injection, sediment–water interaction, nutrients, experimental lakes

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Methylmercury production in the anoxic hypolimnion of a Dimictic Seepage Lake

Water Air & Soil Pollution ◽

10.1007/bf01189725 ◽

1995 ◽

Vol 80 (1-4) ◽

pp. 735-745 ◽

Cited By ~ 77

Author(s):

C. J. Watras ◽

N. S. Bloom ◽

S. A. Claas ◽

K. A. Morrison ◽

C. C. Gilmour ◽

...

Keyword(s):

Anoxic Hypolimnion ◽

Seepage Lake ◽

Methylmercury Production

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A biogeochemical mass balance of 210Po and 210Pb in an oligotrophic lake with seasonally anoxic hypolimnion

Geochimica et Cosmochimica Acta ◽

10.1016/0016-7037(87)90327-9 ◽

1987 ◽

Vol 51 (6) ◽

pp. 1445-1456 ◽

Cited By ~ 33

Author(s):

Gaboury Benoit ◽

Harold F. Hemond

Keyword(s):

Mass Balance ◽

Oligotrophic Lake ◽

Anoxic Hypolimnion

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Microbial Biomass and Enzymatic Activity of the Surface Microlayer and Subsurface Water in Two Dystrophic Lakes

Polish Journal of Microbiology ◽

10.5604/17331331.1234995 ◽

2017 ◽

Vol 66 (1) ◽

pp. 75-84 ◽

Cited By ~ 2

Author(s):

Iwona Kostrzewska-Szlakowska ◽

Bartosz Kiersztyn

Keyword(s):

Microbial Biomass ◽

Inorganic Nitrogen ◽

Subsurface Water ◽

Aminopeptidase Activity ◽

Surface Microlayer ◽

Humic Lakes ◽

Organic Matter Concentration ◽

Subsurface Waters ◽

Nutrient Resources ◽

Polyhumic Lake

Nutrient and organic matter concentration, microbial biomass and activities were studied at the surface microlayers (SML) and subsurface waters (SSW) in two small forest lakes of different water colour. The SML in polyhumic lake is more enriched with dissolved inorganic nitrogen (0.141 mg l–1) than that of oligohumic lake (0.124 mg l–1), the former also contains higher levels of total nitrogen (2.66 mg l–1). Higher activities of lipase (Vmax 2290 nmol l–1 h–1 in oligo- and 6098 in polyhumic) and glucosidase (Vmax 41 nmol l–1 h–1 in oligo- and 49 in polyhumic) were in the SMLs in both lakes. Phosphatase activity was higher in the oligohumic SML than in SSW (Vmax 632 vs. 339 nmol l–1 h–1) while in polyhumic lake was higher in SSW (Vmax 2258 nmol l–1 h–1 vs. 1908 nmol l–1 h–1). Aminopeptidase activity in the SSW in both lakes was higher than in SMLs (Vmax 2117 in oligo- and 1213 nmol l–1 h–1 in polyhumic). It seems that solar radiation does inhibit neuston microbial community as a whole because secondary production and the share of active bacteria in total bacteria number were higher in SSW. However, in the oligohumic lake the abundance of bacteria in the SML was always higher than in the SSW (4.07 vs. 2.69 × 106 cells ml–1) while in the polyhumic lake was roughly equal (4.48 vs. 4.33 × 106 cells ml–1) in both layers. Results may also suggest that surface communities are not supplemented by immigration from bulk communities. The SML of humic lakes may act as important sinks for allochthonous nutrient resources and may then generate considerable energy pools for microbial food webs.

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