scholarly journals Phytoplankton biomass and environmental factors over a gradient of clear to turbid peri-urban ponds. A. Peretyatko, S. Teissier, J.-J. Symoens, L. Triest. Aquatic Conservation: Marine and Freshwater Ecosystems

2007 ◽  
Vol 17 (6) ◽  
Keyword(s):  
Environmental Factors ◽  
Phytoplankton Biomass ◽  
Freshwater Ecosystems ◽  
Aquatic Conservation ◽  
Urban Ponds

Phytoplankton biomass and environmental factors over a gradient of clear to turbid peri-urban ponds

2007 ◽  
Vol 17 (6) ◽  
pp. 584-601 ◽  
Author(s):  
Anatoly Peretyatko ◽  
Samuel Teissier ◽  
Jean-Jacques Symoens ◽  
Ludwig Triest
Keyword(s):  
Environmental Factors ◽  
Phytoplankton Biomass ◽  
Urban Ponds

Bottom-up and top-down effects on phytoplankton functional groups in Hulun Lake, China

2021 ◽  
Vol 57 ◽  
pp. 3
Author(s):  
Chengxue Ma ◽  
Chang Zhao ◽  
Patteson Chula Mwagona ◽  
Ziyu Li ◽  
Zixuan Liu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Phytoplankton Biomass ◽  
Eutrophic Lake ◽  
Positive Influence ◽  
Freshwater Ecosystems ◽  
Top Down ◽  
Bottom Up ◽  
Physical Chemical ◽  
Phytoplankton Functional Groups ◽  
Negative Effect

The debates about the extent to which phytoplankton in freshwater ecosystems are regulated by top-down or bottom-up forces have been ongoing for decades. This study examines the effects of bottom-up and top-down factors on the phytoplankton functional groups in a eutrophic lake. Phytoplankton and zooplankton were sampled and physical-chemical variables measured from May 2019 to October 2019 in Lake Hulun, China. Approximately 43 phytoplankton species were observed and grouped into 23 functional groups. For the zooplankton, about 27 species were observed and classified into 8 functional groups. The study revealed that the bottom-up effects of physical-chemical variables on some phytoplankton functional groups was stronger than the top-down effects of zooplankton. Water temperature (WT), total phosphorus (TP), total nitrogen (TN), conductivity (Cond), water transparency (SD), and dissolved oxygen (DO) significant influence the biomass of the phytoplankton functional groups. The biomass of phytoplankton functional groups was influenced positively by nutrient availability likely because nutrients influence the growth and reproduction of phytoplankton in freshwater. WT and DO had a positive influence on biomass of phytoplankton functional groups. Conversely, phytoplankton biomass revealed a decreasing trend when SD and Cond significantly increased. This study showed that zooplankton functional groups were positively correlated with phytoplankton biomass implying that the top-down control of phytoplankton by the zooplankton in the lake is not strong enough to produce a negative effect. It is evident that the zooplankton functional groups in Lake Hulun are controlled more by bottom-up force than top-down.

scholarly journals DNA metabarcoding of zooplankton communities: species diversity and seasonal variation revealed by 18S rRNA and COI

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11057
Author(s):  
Lina Zhao ◽  
Xue Zhang ◽  
Mengyue Xu ◽  
Ying Mao ◽  
Yuan Huang
Keyword(s):  
Environmental Factors ◽  
Water Temperature ◽  
Total Nitrogen ◽  
Seasonal Changes ◽  
18S Rrna ◽  
Freshwater Ecosystems ◽  
Influential Factors ◽  
Diversity Assessment ◽  
Dna Metabarcoding ◽  
Sanmenxia Reservoir

Background Zooplankton is an important component of aquatic organisms and has important biological and economical significance in freshwater ecosystems. However, traditional methods that rely on morphology to classify zooplankton require expert taxonomic skills. Moreover, traditional classification methods are time-consuming and labor-intensive, which is not practical for the design of conservation measures and ecological management tools based on zooplankton diversity assessment. Methods We used DNA metabarcoding technology with two different markers: the nuclear small subunit ribosomal RNA (18S rRNA) and mitochondrial cytochrome c oxidase (COI), to analyze 72 zooplankton samples collected in 4 seasons and 9 locations from the Sanmenxia Reservoir. We investigated seasonal changes in the zooplankton community and their relationship with water environmental factors. Results A total of 190 species of zooplankton were found, belonging to 12 phyla, 24 classes, 61 orders, 111 families, and 174 genera. Protozoa, especially ciliates, were the most diverse taxa. Richness and relative abundance of zooplankton showed significant seasonal changes. Both alpha and beta diversity showed seasonal trends: the diversity in summer and autumn was higher than that in winter and spring. The zooplankton diversity was most similar in winter and spring. By correlating metabarcoding data and water environmental factors, we proved that water temperature, chemical oxygen demand, total nitrogen and ammoniacal nitrogen were the main environmental factors driving the seasonal changes in zooplankton in the Sanmenxia Reservoir. Water temperature, followed by total nitrogen, were the most influential factors. This study highlights the advantages and some limitations of zooplankton molecular biodiversity assessment using two molecular markers.

Invasibility Patterns of Knotgrass (Paspalum distichum) in Portuguese Riparian Habitats

2005 ◽  
Vol 19 (3) ◽  
pp. 509-516 ◽  
Author(s):  
Francisca C. Aguiar ◽  
M. Teresa Ferreira ◽  
António Albuquerque ◽  
Ivan Bernez
Keyword(s):  
Environmental Factors ◽  
River Basins ◽  
Freshwater Ecosystems ◽  
Fine Sediment ◽  
Fluvial System ◽  
Local Factors ◽  
Mediterranean River ◽  
Riparian Habitats ◽  
Paspalum Distichum ◽  
Surrounding Landscape

Spatial patterns of the exotic riverine knotgrass (Paspalum distichum L.) were examined in Mediterranean river basins in Southwestern Iberia. The major goals of this study were to assess the degree of invasibility of riparian habitats by this species and to determine the influence of environmental factors and human-induced disturbances that this knotgrass has on both the landscape and the habitat scales. The present study demonstrates the ability of knotgrass to invade riparian habitats in Portuguese freshwater ecosystems. However, most of the spatial variation of the knotgrass cover seemed to be driven by local factors, such as fine sediment enrichment and the fragmentation of riparian woods, and by other anthropogenic interferences in relation to both the fluvial system and the surrounding landscape.

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