Search results for "Bloom"
showing 10 items of 65 documents
Sunscreen Products as Emerging Pollutants to Coastal Waters
2013
A growing awareness of the risks associated with skin exposure to ultraviolet (UV) radiation over the past decades has led to increased use of sunscreen cosmetic products leading the introduction of new chemical compounds in the marine environment. Although coastal tourism and recreation are the largest and most rapidly growing activities in the world, the evaluation of sunscreen as source of chemicals to the coastal marine system has not been addressed. Concentrations of chemical UV filters included in the formulation of sunscreens, such as benzophehone 3 (BZ-3), 4-methylbenzylidene camphor (4-MBC), TiO2 and ZnO, are detected in nearshore waters with variable concentrations along the day a…
Toxic cyanobacterial blooms in reservoirs under a semiarid Mediterranean climate: the magnification of a problem
2007
Sicilian reservoirs constitute the most important water resources available on the island. During summer 2001, the intense water utilization of Lake Arancio reservoir reduced the water level significantly. This coincided with the formation of intense blooms formed by the microcystin-producing cyanobacterium Microcystis aeruginosa. During summer 2003, Lake Arancio was continuously filled and the vertical stratification of the water column was maintained, resulting in 5-6 fold lower cell numbers of Microcystis aeruginosa. For both years a significant linear relationship between microcystin net production and Microcysytis cell division was observed, implying that Microcystis cell numbers can b…
Seasonal succession of phytoplankton in an ice-free pond warmed by a thermal power plant
1982
In a pond receiving warmed cooling waters from a thermal power plant, the physical and chemical properties of the water, phytoplankton, periphyton and zooplankton were monitored on a weekly sampling schedule. In winter the phytoplankton growth was limited by poor light conditions. In mid-February a rapid phytoplankton growth started, simultaneously with increasing light energy, high nutrient concentrations and small herbivorous zooplankton populations. The increase of phytoplankton biomass was stopped by lack of free nutrients and silica at the end of March. From May until August the phytoplankton standing crop was mainly regulated by herbivorous zooplankton. The autumnal maximum of phytopl…
Physiological and Technical Aspects of Cactus Pear [Opuntia ficus-indica(L.) Mill.] Double Rellowering and Out-of-Season Winter Fruit Cropping
2007
Abstract A commercial cactus pear plantation in Sicily, Italy was manipulated to induce late cropping. The spring flush of flowers and cladodes were removed as was the second induced bloom of flowers and cladodes. The third induced bloom was harvested for a late out-of-season crop of cactus pear (Opuntia ficus-indica Mill.). The double removal induced a third flush of flowers and cladodes during late August with a fruit production that ripened the following winter (to March). The number of flowers per fertile cladode was halved after the double removal and the length of the fruit development period increased from 100-120 days to 160-190 days for the out-of-season crop. Polyethylene covering…
EVOLUTION OF ENDOGENOUS GIBERELLINS AT DIFFERENT STAGES OF FLOWERING IN RELATION TO RETURN BLOOM OF CACTUS PEAR (OPUNTIA FICUS-INDICA (L.) MILLER)
1998
Abstract The effect of flower emasculation, flower injection with paclobutrazol and the complete removal of the spring flush of flowers and cladodes on the changes in GA 3 concentration at different stages of bloom in flowers and fertile cladodes of Opuntia ficus-indica has been determined. Throughout the bloom period, the concentration of GA 3 was higher in intact flowers and the cladode than in flowers emasculated or injected with paclobutrazol. With the onset of blooming, GA 3 started to accumulate both in the flower and in the fertile cladode, and the highest concentration was measured at full bloom in the flower and in the cladodes whose flowers were not removed. Flower emasculation or…
Inhibitory effects of extracts from the marine alga Caulerpa taxifolia and of toxin from Caulerpa racemosa on multixenobiotic resistance in the marin…
1998
The invasive growth of the introduced green alga Caulerpa taxifolia, already affecting the richness and diversity of the littoral ecosystems, has become a major ecological problem in the Mediterranean Sea. Previously, we demonstrated that the water pollutant tributyltin induces apoptosis in tissue of the marine sponge Geodia cydonium at concentrations of 3 μM and higher. Here we show that exposure of G. cydonium to low (non-toxic) concentrations of Caulerpa extract or purified caulerpin (10 μg/ml) together with low doses of tributyltin (1 μM; non-toxic), results in a strong apoptotic effect. Evidence is presented that the enhancement of toxicity of tributyltin by Caulerpa extract is at leas…
Dinoflagellates from marine algal blooms produce neurotoxic compounds: effects on free calcium levels in neuronal cells and synaptosomes
2000
In this report, evidence is presented that the marine unicellular eukaryotic dinoflagellates can cause neurotoxicity very likely by an increase in intracellular free calcium ions ([Ca(2+)](i)). Determinations of the effects of culture supernatants from different clones of the dinoflagellate Alexandrium sp. isolated from algal blooms on the viability of rat primary neuronal cells revealed that all clones tested were toxic for these cells. In addition, all Alexandrium clones tested, except for A. ostenfeldii BAH ME-141, were found to be toxic for rat pheochromocytoma PC12 cells. No toxicity was observed for culture supernatants from Gonyaulax and Coolia monotis. Calcium ions are important in …
Metal stresses modify soluble proteomes and toxin profiles in two Mediterranean strains of the distributed dinoflagellate Alexandrium pacificum
2022
WOS:000789651000009; HABs involving Alexandrium pacificum have been reported in metal-contaminated ecosystems, suggesting that this distributed species adapts to and/or can tolerate the effects of metals. Modifications in soluble proteomes and PST contents were characterized in two Mediterranean A. pacificum strains exposed to mono- or polymetallic stresses (zinc, lead, copper, cadmium). These strains were isolated from two anthropized locations: Santa Giusta Lagoon (Italy, SG C10-3) and the Tarragona seaport (Spain, TAR C5-4F). In both strains, metals primarily downregulated key photosynthesis proteins. Metals also upregulated other proteins involved in photosynthesis (PCP in both strains)…
Use of phenoclimatic models to estimate the chill and heat requirements of four sweet cherry cultivars in Italy
2017
During their dormant period, fruit trees require a certain amount of relatively low temperatures to complete bud differentiation processes and regularly resume growth the following spring. Unsatisfied chilling needs can result in delayed foliation, severe yield and fruit quality losses. There is a need for a method to estimate accurately the chilling requirement of a cultivar. This is especially important in those areas where the potential of chill accumulation in winter is low and for those crops, such as sweet cherry, which generally have a high chilling requirement. Historical temperature records and blooming dates of four sweet cherry cultivars widely cultivated in Italy - 'Burlat', 'Sw…
THERMAL TIME REQUIREMENT AND HARVEST TIME FORECAST FOR PEACH CULTIVARS WITH DIFFERENT FRUIT DEVELOPMENT PERIODS
2002
Non-linear models using growing degree hours (GDH), based on the choice of base, critical and optimum temperatures, have been successfully applied to calculate thermal time required for spring bud burst in deciduous fruit trees. The flexibility of the model can fit the wide range of temperatures that occur during the peach fruit development period (FDP), which takes place from early spring to late summer. In this experiment, fruit growth was studied in relation to thermal time accumulated from bloom to fruit harvest for peach and nectarine cultivars whose fruit development period range from 70 to 150 days. Thermal time was calculated in terms of degree days (DD) (base temperature 7 °C, and …