Search results for "plankton"
showing 10 items of 549 documents
Population dynamics and ecology of subdominant phytoplankton species in a shallow hypertrophic lake (Albufera of Valencia, Spain)
1994
Long-term population dynamics and ecology of the abundant but non-dominant phytoplankton species of the shallow hypertrophic lake the Albufera of Valencia (Spain) are described for the period 1980–1988. The lake is used as a reservoir for the surrounding ricefield cultivation. It is continuously dominated by three filamentous blue-green algae, Planktothrix agardhii, Pseudanabaena galeata and Geitlerinema sp. Horizontal differences of the phytoplankton were less important than annual and seasonal variations. An annual increasing trend was observed for Planktolyngbya subtilis, Planktolyngbya contorta, Cylindrospermopsis raciborskii, Microcystis incerta, Nitzschia palea var. tenuirostris and R…
Phytoplankton colonization patterns and the abundance of suitable aquatic ecosystems: the importance of nestedness among freshwaters. 17th Workshop o…
2014
Species-poor and species-rich phytoplankton assemblages in two Sicilian water bodies (Lake Pergusa and Lake Biviere di Gela) were compared to test the hypothesis that the number of colonization events and the successful establishment of a new species in an aquatic ecosystem may depend on the number and nestedness of water bodies in a given area. The two ecosystems are both natural, shallow lakes and they are protected sites hosting a rich avifauna. Both the lakes had quite high conductivity values (> 2,500 μS cm-1) and both were re-filled with fresh waters (< 400 μS cm-1) after they had disappeared because of the over-exploitation of their main inflows to fulfill agriculture water-demand. H…
Equilibrium/steady-state concept in phytoplankton ecology
2003
This paper summarises the outcomes of the 13th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP). The authors mostly addressed their contributions on the following topics: the effect of trophic state on the attainment of a steady-state; the establishment of equilibria in deep and shallow lakes; the role of spatial heterogeneity, disturbance, and stress in the establishment of equilibrium assemblages; the mechanisms leading to the steady state; the frequency and longevity of equilibrium phases, and the role of morphological and physiological plasticity of phytoplankton in maintaining the (apparently) same populations under different environmental condition…
Towards a quality assessment of freshwater ecosystems through the morphological analysis of phytoplankton.
2012
Among the organisms living at low Reynolds numbers, those belonging to the ecological group of phytoplankton offer an amazing morphological diversity and all the scientists involved in phytoplankton research have commonly observed that they may express a quite high variability, both intra- and inter-specific, in their size and morphology. These features have been traditionally used just for taxonomic classification. However, the ecological value of morphological descriptors in phytoplankton is increasingly used to investigate their abilities in resource (light and nutrients) uptake as a result of natural selection and competition. At the same time, the analysis of suitable morphology and si…
Steady-state assemblages in a Mediterranean hypertrophic reservoir. The role of Microcystis ecomorphological variability in maintaining an apparent e…
2003
Lake Arancio is a hypertrophicMediterranean man-made lake, located on the southern coast of Sicily. Its artificial origin and the climate make it a very dynamic environment, strongly characterised by very wide water-level fluctuations. These vertical water movements interfere with the thermal stability of the water body often causing the breaking of the thermocline in mid-summer. In addition, the summer level-decrease influences the nutrient dynamics and modifies the zmix/zeu ratio. All these modifications were observed to support a high environmental variability, which was reflected by the richness of its phytoplankton composition and by its dynamics. Nevertheless, an investigation carried…
Different key roles of mesoscale oceanographic structures and ocean bathymetry in shaping larval fish distribution pattern: A case study in Sicilian …
2016
Fish larvae data collected in year 2009 were used to examine the effects of particular environmental conditions on the structure of larvalassemblages in two oligotrophic Mediterranean areas (the Southern Tyrrhenian Sea and the Strait of Sicily). For this purpose, relationships with environmental variables (temperature, salinity and fluorescence), zooplankton biomass, water circulation and bathymetry are discussed. Hydrodynamic conditions resulted very differently between two study areas. The Southern Tyrrhenian Sea was characterized by moderate shallow circulation compared to the Strait of Sicily. In this framework, distribution pattern of larval density in the Tyrrhenian Sea was mainly dri…
Trophic structure of vermetid reef community: High trophic diversity at small spatial scales
2013
Stable isotopes were used to investigate contributions of autochthonous (i.e. benthic: epilithon and macroalgae) and allochthonous (i.e. pelagic: phytoplankton) organic matter sources to the diet of suspension-feeders, grazers and predators associated to small reef-pools (cuvettes) created by the reef-building species Dendropoma petraeum in the north-western coast of Sicily (Italy). Contributions of potential food sources were calculated using Bayesian mixing-models and integrated to a multivariate approach to highlight the diversity of C and N pathways within Dendropoma cuvettes. Both pelagic and benthic organic matter sources were exploited by benthic consumers, although clear differences…
Consequences of Stinging Plankton Blooms on Finfish Mariculture in the Mediterranean Sea
2017
11 pages, 8 figures, 2 tables, supplementary material http://journal.frontiersin.org/article/10.3389/fmars.2017.00240/full#supplementary-material
Impacts of marine aquaculture at large spatial scales: evidences from n and p catchment loading and phytoplankton biomass
2011
International audience; While several studies point at off-shore aquaculture as a possible source of impacts on the local marine environment, very few have analysed its effects at large scales such as at the bay, gulf or basin levels. Similar analyses are hampered by the multiple sources of disturbance that may concomitantly affect a given area. The present paper addresses these issues taking the Gulf of Castellammare (Southern Tyrrhenian Sea) as an example. Nitrogen (N) and phosphorous (P) loads were calculated for the period 1970-2007, and compared to chlorophyll-a concentration as measured inside and outside the Gulf over the same period. Results indicate that N and P catchment loading h…
On the occurrence and distribution of Calanipeda aquaedulcis Kritschagin, 1873 (Copepoda, Calanoida, Pseudodiaptomidae) in Sicily, Italy, with some n…
2019
The only population of the pseudodiaptomid copepod Calanipeda aquaedulcis Kritschagin, 1873 to date reported to occur in Sicily disappeared at the beginning of the XXI century due to deep environmental changes which affected the single site (Lake Biviere di Gela) known for this species on the island. In that site C. aquaedulcis is now replaced by Copidodiaptomus numidicus (Gurney, 1909), a diaptomid copepod whose distribution has been greatly increasing since the second half of the last century. In the present note, the occurrence of C. aquaedulcis in 12 novel water bodies spread throughout Sicily is reported, and some environmental data on the sites where the species was collected are prov…