scholarly journals Vallisneria americana (Hydrocharitaceae) as a biomonitor of aquatic ecosystems: comparison of cloned genotypes

1997 ◽  
Vol 84 (12) ◽  
pp. 1743-1751 ◽  
Author(s):  
Maciej Biernacki ◽  
Jon Lovett-Doust
Keyword(s):  
Aquatic Ecosystems ◽  
Vallisneria Americana

scholarly journals Ecotypes of Aquatic Plant Vallisneria americana Tolerate Different Salinity Concentrations

2020 ◽  
Author(s):  
Mohsen Tootoonchi ◽  
Lyn Gettys ◽  
Kyle Thayer ◽  
Ian Markovich ◽  
Joseph Sigmon ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Aquatic Plant ◽  
Plant Biomass ◽  
Visual Quality ◽  
Freshwater Ecosystems ◽  
Control Treatment ◽  
Vallisneria Americana ◽  
Abiotic Conditions ◽  
Saline Solutions ◽  
Normal Salinity

Increased salinity caused by saltwater intrusion or runoff from de-icing salts can severely affect freshwater vegetation and deteriorate aquatic ecosystems. These habitats can be restored with freshwater ecotypes (locally adapted populations) that tolerate above-normal salinity. Vallisneria americana is a prominent species in many freshwater ecosystems that responds differently to abiotic conditions such as substrate composition and fertility, so in this study we evaluated the effects of salt stress on 24 ecotypes of V. americana. Instant Ocean aquarium salt was used to create saline solutions [0.2 to 20.0 parts per thousand (ppt)], then plants were abruptly exposed to these solutions and maintained in these concentrations for 5 weeks before being visually assessed for quality and destructively harvested. Analysis of variance and non-linear regression were used to calculate LC50 values – the lethal concentration of salt that reduced plant biomass and quality by 50% compared to control treatment. Growth rate and visual quality varied significantly among ecotypes, and ecotypes that were most and least sensitive to salt had 50% biomass reductions at 0.47 and 9.10 ppt, respectively. All ecotypes survived 10.0 ppt salinity concentration but none survived at 20.0 ppt, which suggests the maximum salinity concentration tolerated by these ecotypes is between 15.0 and 20.0 ppt.

scholarly journals Ecotypes of Aquatic Plant Vallisneria americana Tolerate Different Salinity Concentrations

Diversity ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 65
Author(s):  
Mohsen Tootoonchi ◽  
Lyn A Gettys ◽  
Kyle L Thayer ◽  
Ian J Markovich ◽  
Joseph W Sigmon ◽  
...  
Keyword(s):  
Aquatic Ecosystems ◽  
Aquatic Plant ◽  
Plant Biomass ◽  
Visual Quality ◽  
Freshwater Ecosystems ◽  
Control Treatment ◽  
Vallisneria Americana ◽  
Abiotic Conditions ◽  
Saline Solutions ◽  
Normal Salinity

Increased salinity caused by saltwater intrusion or runoff from de-icing salts can severely affect freshwater vegetation and deteriorate aquatic ecosystems. These habitats can be restored with freshwater ecotypes (locally adapted populations) that tolerate above-normal salinity. Vallisneria americana is a prominent species in many freshwater ecosystems that responds differently to abiotic conditions such as substrate composition and fertility, so, in this study, we evaluated the effects of salt stress on 24 ecotypes of V. americana. Instant Ocean aquarium salt was used to create saline solutions (0.2 to 20.0 parts per thousand (ppt)), then plants were abruptly exposed to these solutions and maintained in these concentrations for five weeks before being visually assessed for quality and destructively harvested. Analysis of variance and nonlinear regression were used to calculate LC50 values—the lethal concentration of salt that reduced plant biomass and quality by 50% compared to control treatment. Growth rate and visual quality varied significantly among ecotypes, and ecotypes that were most and least sensitive to salt had 50% biomass reductions at 0.47 and 9.10 ppt, respectively. All ecotypes survived 10.0 ppt salinity concentration but none survived at 20.0 ppt, which suggests that the maximum salinity concentration tolerated by these ecotypes is between 15.0 and 20.0 ppt.

Extracellular enzymatic activities in the aquatic ecosystems of the Danube Delta. 2. Alkaline phosphatase activity

2021 ◽  
Vol 26 (1) ◽  
pp. 2269-2274
Author(s):  
IOAN PĂCEŞILĂ ◽  
EMILIA RADU
Keyword(s):  
Alkaline Phosphatase ◽  
Water Column ◽  
Aquatic Ecosystems ◽  
Temporal Dynamics ◽  
Extracellular Enzyme ◽  
Danube Delta ◽  
Phytoplankton Communities ◽  
Extracellular Enzymatic Activities ◽  
Adjacent Channels ◽  
Hydrolysis Of

Phosphorus is one of the most important inorganic nutrients in aquatic ecosystems, the development and functioning of the phytoplankton communities being often correlated with the degree of availability in assimilable forms of this element. Alkaline phosphatase (AP) is an extracellular enzyme with nonspecific activity that catalyses the hydrolysis of a large variety of organic phosphate esters and release orthophosphates. During 2011-2013, AP Activity (APA) was assessed in the water column and sediments of several aquatic ecosystems from Danube Delta: Roșu Lake, Mândra Lake and their adjacent channels – Roșu-Împuțita and Roșu-Puiu. The intensity of APA widely fluctuated, ranging between 230-2578 nmol p-nitrophenol L-1h-1 in the water column and 2104-15631 nmol p-nitrophenol g-1h-1 in sediment. Along the entire period of the study, APA was the most intense in Roșu-Împuțita channel, for both water and sediment samples. Temporal dynamics revealed its highest values in summer for the water column and in autumn for sediment. Statistical analysis showed significant seasonal diferences of the APA dynamics in spring vs. summer and autumn for the water column, and any relevant diferences for sediment.

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