Excretion of total phosphorus, dissolved reactive phosphorus, ammonia, and urea by Lake Michigan Mysis relicta

Abstract Poultry litter ash (PLA) is a byproduct of bioenergy production and an effective P source for horticultural crops since it reduces P losses from container production due to its low P solubility. Experiments were conducted to determine effects of rate and placement of PLA on P loss from greenhouse crop production and growth and quality of two commonly-grown greenhouse crops, Verbena canadensis Britton ‘Homestead Purple' and Lantana camara L. ‘New Gold', by comparing two rates (140 and 280 g·m−3 P or 0.4 and 0.8 lb·yd−3) and two application methods (post-plant topdressed and pre-plant incorporated). Leachate-dissolved reactive phosphorus (DRP) concentrations were reduced by an average of 24% as P rate was reduced from 280 to 140 g·m−3, but were 134% less on average when PLA was topdressed instead of incorporated. Foliar P concentrations were less 33% and 44% for verbena and lantana, respectively when plants were topdressed compared to incorporated. Shoot biomass of verbena and lantana was 9% and 24% greater, respectively, when incorporating instead of topdressing PLA. As a P source, PLA should be pre-plant incorporated within the substrate at a total P rate between 140 g·m−3 (0.4 lb·yd−3) and 280 g·m−3 (0.8 lb·yd−3). Index words: phosphorus, poultry litter ash, Verbena canadensis Britton ‘Homestead Purple', Lantana camara L. ‘New Gold', dissolved reactive phosphorus. Species used in this study: ‘Homestead Purple' verbena (Verbena canadensis Britton); ‘New Gold' lantana (Lantana camara L.).

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Mysis relicta in Lake Michigan: Abundances and Relationships with their Potential Prey, Daphnia

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-112 ◽

1990 ◽

Vol 47 (5) ◽

pp. 977-983 ◽

Cited By ~ 22

Author(s):

John T. Lehman ◽

James A. Bowers ◽

Robert W. Gensemer ◽

Glenn J. Warren ◽

Donn K. Branstrator

Keyword(s):

Lake Michigan ◽

Puget Sound ◽

Mortality Rates ◽

Reference Station ◽

Potential Prey ◽

Mysis Relicta ◽

The North ◽

Important Predator ◽

Vertical Distributions

Mysis relicta were sampled at a 100-m reference staton in southeastern Lake Michigan (43°N 86°40′W) from 1985 to 1989, to quantify nighttime water column abundances and to compare vertical distributions with those of Daphnia. Diel vertical migration produced maximum concentrations in the thermocline at night of 1 to 10 mysids∙m−3. Variation among replicates averaged 28% with a 3-net Tucker trawl and 19% with Puget Sound vertical closing nets. Mean areal abundances over 5 yr averaged 110 mysids∙m−2 (SE = 20; n = 30; range = 25 to 645) based on nighttime vertical and oblique net tows at 1–3-wk intervals during summers at the reference station. Synoptic cruises from 43°N to 45°N during August indicated that densities were considerably greater offshore than inshore, and greater in the north than in the south. Hypothesized long-term changes in mysid abundances were not detected. Although Mysis is potentially an important predator on Daphnia, differences in nighttime vertical distributions reduce encounters between Mysis and Daphnia during summer in Lake Michigan, such that Mysis exert mortality rates on Daphnia of < 1.5% per day; the latter are in general less than 10% of the birth rates of Daphnia populations, estimated from fecundities.

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Measurements of Dissolved Adenosine Triphosphate in Lake Michigan

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-073 ◽

1983 ◽

Vol 40 (4) ◽

pp. 542-547 ◽

Cited By ~ 6

Author(s):

James S. Maki ◽

Michael E. Sierszen ◽

Charles C. Remsen

Keyword(s):

Microbial Biomass ◽

Adenosine Triphosphate ◽

Lake Michigan ◽

Laboratory Work ◽

Vertical Profiles ◽

Mysis Relicta ◽

Filtration Method ◽

Filtration Effect

Comparisons of two methods of separating dissolved adenosine triphosphate (dATP) were made, both in the laboratory and in vertical profiles in Lake Michigan. Laboratory work indicated that filtration through a 0.2-μm pore filter or centrifugation of samples gave similar concentrations of dATP. In Lake Michigan, however, the filtration method gave significantly higher dATP concentrations suggesting some adverse filtration effect. Therefore, centrifugation was chosen as the method to determine dATP. Resulting particulate ATP (pATP) concentrations indicated the highest levels of microbial biomass were located below the epilimnion. Feeding by Mysis relicta appeared to decrease pATP but not release much dATP.

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Impacts of drying and reflooding on water quality of a tropical semi-arid reservoir during an extended drought event

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x6918 ◽

2019 ◽

Vol 31 ◽

Author(s):

Jéssica Nayara de Carvalho Leite ◽

Vanessa Becker

Keyword(s):

Water Quality ◽

Electrical Conductivity ◽

Chlorophyll A ◽

Total Phosphorus ◽

Algal Biomass ◽

Soluble Reactive Phosphorus ◽

Drought Event ◽

Reactive Phosphorus ◽

Semi Arid

Abstract Aim The aim of this study was to analyze the water quality of a tropical, semi-arid reservoir after a reflooding. In terms of impact on water quality after a drought event, it is expected that there will be improvements with the reflooding. Less algal biomass, increased water transparency, decreased turbidity and low nutrient concentration. Methods This study was performed in a tropical, semi-arid man-made lake (Dourado Reservoir), during an extended drought period. This study consisted of a comparison of three distinct periods determined by water accumulation. The limnological variables, including water transparency, turbidity, electrical conductivity, pH, total phosphorus, soluble reactive phosphorus, and chlorophyll-a were analyzed. A principal component analysis (PCA) was also performed to verify the patterns of the variables in relation to the sample units in the studied periods. Results After water renewal, there was an expressive reduction in chlorophyll-a. Electrical conductivity, pH, and turbidity variables also reduced after the reflooding, indicating an improvement in water quality. There was no reduction in total phosphorus and soluble reactive phosphorus after the reflooding compared to the previous periods. Conclusions The significant reduction in algal biomass after reflooding in Dourado indicates water quality improvement in terms of eutrophication due to the change of the trophic state from eutrophic to mesotrophic.

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