Responses of Ulva prolifera to short-term nutrient enrichment under light and dark conditions

Short-term nutrient enrichment and zooplankton exclosure experiments were conducted at 14 lakes representing various stages of acidification (pH 4.6-6.8). We measured changes in chlorophyll as an indicator of the severity of nutrient limitation and grazing intensity and compared these with independent measures of P limitation (cell P quotas and phosphatase activity) and grazing (zooplankton densities and inferred community grazing rates). Results from nutrient enrichment experiments showed good correspondence to measured phosphatase activity but not cell P quotas. Phytoplankton in acidic lakes (pH < 5.0) responded more strongly to nutrient enrichment and exhibited fourfold higher biomass-specific phosphatase activity compared with nonacidic lakes. Phytoplankton responses to the removal of macrozooplankton did not exhibit any consistent pattern among lakes of varying acidity. Although the largest herbivores (Daphnia) were more abundant in nonacidic lakes, their absence in acidic lakes was compensated for by increased abundance of smaller species (principally Diaptomus minutus and Bosmina longirostris). The magnitude of the response to grazer removal was positively correlated with lake zooplankton densities at the time of the experiment, and the use of a nonlinear model enabled us to explain 84% of the variation in this response among the 14 sites.

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Short-term responses of phytoplankton to nutrient enrichment and planktivorous fish predation in a temperate South American mesotrophic reservoir

Hydrobiologia ◽

10.1007/s10750-007-9182-2 ◽

2007 ◽

Vol 600 (1) ◽

pp. 131-138 ◽

Cited By ~ 12

Author(s):

P. Acuña ◽

I. Vila ◽

V. H. Marín

Keyword(s):

Nutrient Enrichment ◽

Fish Predation ◽

Planktivorous Fish ◽

South American ◽

Short Term

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Response of seagrass (Thalassia testudinum) metrics to short-term nutrient enrichment and grazing manipulations

Journal of Experimental Marine Biology and Ecology ◽

10.1016/j.jembe.2016.09.015 ◽

2017 ◽

Vol 486 ◽

pp. 105-113 ◽

Cited By ~ 7

Author(s):

Troy Mutchler ◽

Daniel K. Hoffman

Keyword(s):

Nutrient Enrichment ◽

Thalassia Testudinum ◽

Short Term

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Soil acidification reduces the effects of short‐term nutrient enrichment on plant and soil biota and their interactions in grasslands

Global Change Biology ◽

10.1111/gcb.15167 ◽

2020 ◽

Vol 26 (8) ◽

pp. 4626-4637 ◽

Cited By ~ 2

Author(s):

Hong Xiao ◽

Bing Wang ◽

Shunbao Lu ◽

Dima Chen ◽

Ying Wu ◽

...

Keyword(s):

Nutrient Enrichment ◽

Soil Acidification ◽

Soil Biota ◽

Short Term

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Silicon Contamination in Diatom Nutrient Enrichment Experiments

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-088 ◽

1983 ◽

Vol 40 (5) ◽

pp. 657-664 ◽

Cited By ~ 5

Author(s):

Stephen J. Tarapchak ◽

David R. Slavens ◽

Michael A. Quigley ◽

Judith S. Tarapchak

Keyword(s):

Growth Rates ◽

Nutrient Enrichment ◽

Lake Michigan ◽

Pyrex Glass ◽

Short Term ◽

Photosynthetic Rates ◽

Nutrient Bioassay ◽

Enrichment Experiments ◽

Silicon Contamination

Large amounts of biologically available silicon (Si) were released into solution from the walls of Pyrex glass reagent bottles and Erlenmeyer flasks during nutrient bioassay experiments using Lake Michigan water. Photosynthetic rates in short-term (4–7 h) incubations and diatom growth rates and maximum yields in long-term incubations (~7 d) were affected by these extraneous Si supplies. The results of conventional nutrient enrichment bioassays performed in low-Si environments can be seriously biased unless Si contamination from glass incubation containers is avoided.

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Short-term effects of nutrient enrichment on river biofilm: N–NO3 − uptake rate and response of meiofauna

Hydrobiologia ◽

10.1007/s10750-014-2074-3 ◽

2014 ◽

Vol 744 (1) ◽

pp. 165-175 ◽

Cited By ~ 10

Author(s):

Yang Liu ◽

Nabil Majdi ◽

Michèle Tackx ◽

Alain Dauta ◽

Magali Gerino ◽

...

Keyword(s):

Nutrient Enrichment ◽

Uptake Rate ◽

Short Term ◽

River Biofilm ◽

Short Term Effects

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Evolutionary rescue of a green alga kept in the dark

Biology Letters ◽

10.1098/rsbl.2012.0823 ◽

2013 ◽

Vol 9 (1) ◽

pp. 20120823 ◽

Cited By ~ 12

Author(s):

Graham Bell

Keyword(s):

Short Term ◽

Term Experiment ◽

Evolutionary Rescue ◽

Extreme Phenotypes ◽

Long Term Experiment ◽

Sexual Histories ◽

Dark Conditions ◽

Set Up ◽

Asexual Populations

Chlamydomonas (Chlorophyta) can grow as a heterotroph on medium supplemented with acetate in the dark. A long-term experiment to investigate adaptation to dark conditions was set up with hundreds of replicate lines. Growth was initially slow, and most lines became extinct when transferred every few weeks. Some lines survived through the expansion of lineages derived from cells with extreme phenotypes and exhibited a U-shaped curve of collapse and recovery. Two short-term experiments were set up to evaluate the effect of sex on the frequency of ‘evolutionary rescue’ by deriving replicate lines from ancestral populations with contrasting sexual histories that had been cultured in the light for hundreds of generations. When transferred to dark conditions of growth, lines derived from obligately sexual populations survived more often than lines derived from facultatively sexual or asexual populations. This reflected the higher initial frequency of cells able to grow in the dark, due to greater genetic diversity supported by sexual fusion and recombination. The greater probability of evolutionary rescue suggests a general reason for the prevalence of sexual species.

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Hyper-Nutrient Enrichment Status in the Sabalan Lake, Iran

Water ◽

10.3390/w13202874 ◽

2021 ◽

Vol 13 (20) ◽

pp. 2874

Author(s):

Roohollah Noori ◽

Elmira Ansari ◽

Yong-Wook Jeong ◽

Saber Aradpour ◽

Mohsen Maghrebi ◽

...

Keyword(s):

Nutrient Enrichment ◽

Management Practices ◽

Storage Capacity ◽

Limiting Factors ◽

Molar Ratio ◽

Anthropogenic Factors ◽

Short Term ◽

Reservoir Water ◽

P Deficiency

Lakes/reservoirs are rapidly deteriorating from cultural eutrophication due to anthropogenic factors. In this study, we aimed to (1) explore nutrient levels in the Sabalan dam reservoir (SDR) of northwest Iran, (2) determine the reservoir water fertility using the total phosphorus (TP)based and total nitrogen (TN)based Carlson trophic state indices, and (3) specify primary limiting factors for the reservoir eutrophication. Our field observations showed a state of hyper-nutrient enrichment in the SDR. The highest variation of TN in the reservoir water column happened when the reservoir was severely stratified (in August) while the highest variation of TP took place when the thermocline was attenuated with the deepening of the epilimnion (in October). Both TP and TN based trophic indicators classified the SDR as a hypereutrophic lake. TN:TP molar ratio averaged at the epilimnion indicated a P–deficiency in the reservoir during warm months whilst it suggested a co–deficiency of P and N in cold months. Given the hyper-nutrient enrichment state in the reservoir, other drivers such as water residence time (WRT) can also act as the main contributor of eutrophication in the SDR. We found that WRT in the SDR varied from hundreds to thousands of days, which was much longer than that of other reservoirs/lakes with the same and even much greater storage capacity. Therefore, both hyper-nutrient enrichment and WRT mainly controlled eutrophication in the reservoir. Given time consuming and expensive management practices for reducing nutrients in the watershed, changes in the SDR operation are suggested to somewhat recover its hypereutrophic state in the short-term. However, strategic long-term recovery plans are required to reduce the transition of nutrients from the watershed to the SDR.

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