Diurnal variations in the auto- and heterotrophic activity of cyanobacterial phycospheres (Gloeotrichia echinulata) and the identity of attached bacteria

The response of attached bacteria to Zn at three pH levels was studied in outdoor stream mesocosms. Streams containing water from Crooked Lake, Indiana, were dosed with either 0.1 or 0.5 mg Zn/L at ambient pH (pH 8.4), pH 7.0, or pH 5.5. Samples were taken at 2, 5, 10, and 20 days and analyzed for total biomass, chlorophyll content, total bacterial numbers, and heterotrophic activity. All measures of community abundance and activity were highest in the treatment receiving 0.1 mg/L at a pH of 8.4. Treatments at lower pH levels and the higher Zn concentration showed significantly lower biomass, chlorophyll content, and total bacterial numbers. Bacterial heterotrophic activity did not demonstrate a statistically significant response as pH decreased, although it did show a statistically significant decrease at a concentration of 0.5 mg Zn/L. The portion of the bacterial community able to grow on nutrient agar demonstrated adaptation to the increased toxicity of Zn at lower pH levels by an increase in the proportion of bacteria resistant to Zn. In addition, the structure of the culturable bacterial community was altered at low pH, as demonstrated by a reduction in the Shannon–Wiener diversity index. The results indicate that pH can modulate Zn toxicity to the attached community. Key words: attached bacteria, zinc, heavy metal resistance, acid rain, species diversity.

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DIURNAL VARIATIONS IN THE EXCRETION PATTERNS OF FREE AND CONJUGATED CATECHOLAMINES IN URINE.

Acta Endocrinologica ◽

10.1530/acta.0.103s177 ◽

1983 ◽

Vol 104 (2_Supplb) ◽

pp. S177-S187

Author(s):

J. Odink ◽

H. Sandman ◽

A.J. Speek ◽

W.H.P. Schreurs

Keyword(s):

Diurnal Variations ◽

Catecholamines In Urine

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0870 Percentages of milk fat, lactose, and protein are affected by diurnal variations in dairy goats

Journal of Animal Science ◽

10.2527/jam2016-0870 ◽

2016 ◽

Vol 94 (suppl_5) ◽

pp. 418-418

Author(s):

F. Rosa ◽

J. S. Osorio ◽

J. Lohakare ◽

M. Moridi ◽

A. Ferrari ◽

...

Keyword(s):

Milk Fat ◽

Diurnal Variations ◽

Dairy Goats

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Role of filter media in an anaerobic fixed-bed reactor

Water Science & Technology ◽

10.2166/wst.1995.0353 ◽

1995 ◽

Vol 31 (9) ◽

pp. 137-144 ◽

Cited By ~ 3

Author(s):

T. Miyahara ◽

M. Takano ◽

T. Noike

Keyword(s):

Anaerobic Bacteria ◽

Fixed Bed ◽

Methanogenic Bacteria ◽

The Other ◽

Fixed Bed Reactor ◽

Filter Media ◽

Fixed Bed Reactors ◽

Attached Bacteria ◽

The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

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