Search results for "plankton"
showing 9 items of 549 documents
Water chemistry, zooplankton and benthos in small lakes within the distribution area of the rare European pool frog Pelophylax lessonae (Camerano) in…
2020
Summary In June 2018, water chemistry, benthos and zooplankton were investigated in 7 small lakes/ ponds within the key area of the European pool frog Pelophylax lessonae (Camerano) in Norway. The geographic distribution of the Norwegian population is minor, limited to a very few small lakes in the county of Agder in southernmost Norway. Since the species is thermophilic, reproduction success only occurs in warm summers. Accordingly, the pool frog is one of the most rare vertebrates in Norwegian fauna, classified as critically endangered in the Norwegian red list. A breeding program is today established in order to rescue this species.The article deals with potential biotope challenges most…
Limnological aspects of sicilian reservoirs: A comparative, ecosystemic approach
1999
This paper is a report on the state-of-the-art of reservoir limnology in Sicily, the largest island of the Mediterranean Sea. The territory is characterised by a semi-arid climate with a dry and a wet semester occurring in the year. Evaporative losses are strong during the summer and, on an annual basis, they often exceed precipitation. Thus, reservoirs constitute an important water resource for the island to supply drinking water and to provide for agricultural needs in the periods of drought. However, despite their importance, they receive poor attention from the scientific and political communities and in the absence of any environmental policy or suitable territorial planning, their wat…
The importance of phytoplankton production for carbon budgets in a semiarid floodplain wetland
2011
Phytoplankton production (PP) in wetlands is not measured as often as that of macrophytes. A three year-study during a period of sustained high flooding was undertaken in a central Spanish floodplain wetland (Las Tablas de Daimiel National Park) to determine net PP, its spatial heterogeneity and controlling factors, and compare it with primary production in macrophyte communities. This enabled us to estimate carbon budgets for each community. All PP variables showed high spatial and temporal variability among sites, resulting in low coherence even when flooding connected all sites. Net PP corresponded to 25- 36% of submerged plant production and 3-10% of helophyte production. Net PP was con…
Ecological and evolutionary impact of diapause on zooplankton
2012
La diapausa es un tipo de dormición que permite a los organismos sobrevivir a periodos ambientales desfavorables y lidiar con la impredicibilidad del hábitat. La producción de huevos diapáusicos es especialmente común en especies de invertebrados acuáticos como ostrácodos, anostráceos, notostráceos, copépodos, cladóceros o rotíferos. La presente tesis profundiza en el estudio de las implicaciones ecológicas y evolutivas de la diapausa tanto a nivel poblacional, como a nivel de comunidad. A nivel poblacional, se estudia el impacto de los bancos de huevos sobre la diferenciación genética poblacional y su relación con el flujo génico, la deriva genética y los efectos fundadores persistentes. L…
Does differential iron supply to algae affect Daphnia life history? : An ionome-wide study
2019
The availability of iron (Fe) varies considerably among diet items, as well as ecosystems. Availability of Fe has also changed due to anthropogenic environmental changes in oceanic as well as inland ecosystems. We know little about its role in the nutrition of ecologically important consumers, particularly in inland ecosystems. Physiological studies in several taxa indicate marked effects of dietary Fe on oogenesis. We predicted that differential Fe supply to algae will impact algal Fe concentration with consequences on the life history of the freshwater grazer, Daphnia magna. We found that algal Fe concentration increased with Fe supply, but did not affect algal growth, indicating that the…
Browning-induced changes in trophic functioning of planktonic food webs in temperate and boreal lakes: insights from fatty acids
2022
AbstractThe effects of lake browning on trophic functioning of planktonic food webs are not fully understood. We studied the effects of browning on the response patterns of polyunsaturated fatty acids and n−3/n−6 ratio in seston and compared them between boreal and temperate lakes. We also compared the regional differences and the effects of lake browning on the reliance of zooplankton on heterotrophic microbial pathways and the mass fractions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in zooplankton. Lake browning was associated with increasing phytoplankton biomass and concentrations of EPA and DHA in both temperate and boreal lakes, but the seston n−3/n−6 ratio was low…
Relationship between trophic state and plankton community structure in 21 Sicilian dam reservoirs
1994
The relationship between the trophic state of 21 Sicilian dam reservoirs and their taxonomic community structure of phytoplankton (87 taxa) as well as zooplankton (45 taxa) have been examined by means of cluster analysis performed using annual average biomass values. The phytoplankton community structure was closely connected with the trophic state of the reservoirs, whereas the zooplankton community structure was related to hydrological regimes peculiar to the individual water bodies and not to the trophic state. © 1994 Kluwer Academic Publishers.