The research proposal aims at studying, both in marine and freshwater water bodies, the synthesis and the expression of microbial enzymes involved in carbon and phosphorus cycles and the interrelationships between the bacterioplankton and phytoplanktonic communities. The goal of the research is to achieve a better understanding of the mechanisms/environmental forcings which regulate the microbial metabolism in different trophic conditions. Particular interest will be addressed to the study of the dynamics of alkaline phosphatase, according to the role played by this enzyme in phosphorus regeneration and the appearance of eutrophication episodes in natural environments. The experimental activities will be performed, for each Institute participating to the project, in some ecosystems which show trophic gradients and suffer the occurrence of algal blooms (in particular, shallow marine and brackish Marinello and Cape Peloro lakes in Italy; shallow freshwater Chaohu lake and the lakes near to Wuhan Town, in China); the environmental characteristics of these areas have already been investigated. The study will examine the pelagic and benthic compartment of areas with different trophic conditions, showing the prevalence of autotrophic or heterotrophic processes (or of productive and degradative processes, respectively). During the 1st year of activity, measurements of enzymatic activity rates (leucin aminopeptidase, ?-glucosidase, alkaline phosphatase) on whole and size-fractionated samples, counts of total and autotrophic bacterioplankton, aerobic heterotrophic bacteria, organic and inorganic phosphobacteria, quali- and quantitative study of phytoplankton will be performed at a seasonal scale at each studied lake; at the same time, the main physical and chemical parameters (temperature, salinity, dissolved oxygen, particulate organic carbon (POC) and nitrogen (PON) and dissolved organic carbon (DOC), chlorophyll-a content, will be measured. During the 2nd year of activity, the study will be continued following the previous time schedule, in order to point out inter-annual variations in the dynamics of organic matter decomposition and nutrient release. During this phase, research activities will dealt with some qualitative features (discrimination, within the bacterioplankton community, of the living and metabolically active component from the inactive one; identification of the algal species responsible for the enzymatic synthesis), in order to improve knowledge of the potentialities played by different microbial populations in organic matter decomposition. As a future perspective of research, experiments in micro- or mesocosms will be planned to verify what found by the field studies. The scientific significance of the proposal relies on the possibility of testing the hypothesis of using the parameter "alkaline phosphatase" alone or in association with another microbial (or environmental) parameter as a potential biomarker for monitoring the health status of marine and freshwater water bodies and early detecting the occurrence of algal blooms due to P excess.
Understanding expression and regulation of microbial enzymes involved in organic matter decomposition (carbon and phosphorus cycles) and the interrelationship between alkaline phosphatase and eutrophication in Italian and Chinese water bodies
Caruso G
2010
Abstract
The research proposal aims at studying, both in marine and freshwater water bodies, the synthesis and the expression of microbial enzymes involved in carbon and phosphorus cycles and the interrelationships between the bacterioplankton and phytoplanktonic communities. The goal of the research is to achieve a better understanding of the mechanisms/environmental forcings which regulate the microbial metabolism in different trophic conditions. Particular interest will be addressed to the study of the dynamics of alkaline phosphatase, according to the role played by this enzyme in phosphorus regeneration and the appearance of eutrophication episodes in natural environments. The experimental activities will be performed, for each Institute participating to the project, in some ecosystems which show trophic gradients and suffer the occurrence of algal blooms (in particular, shallow marine and brackish Marinello and Cape Peloro lakes in Italy; shallow freshwater Chaohu lake and the lakes near to Wuhan Town, in China); the environmental characteristics of these areas have already been investigated. The study will examine the pelagic and benthic compartment of areas with different trophic conditions, showing the prevalence of autotrophic or heterotrophic processes (or of productive and degradative processes, respectively). During the 1st year of activity, measurements of enzymatic activity rates (leucin aminopeptidase, ?-glucosidase, alkaline phosphatase) on whole and size-fractionated samples, counts of total and autotrophic bacterioplankton, aerobic heterotrophic bacteria, organic and inorganic phosphobacteria, quali- and quantitative study of phytoplankton will be performed at a seasonal scale at each studied lake; at the same time, the main physical and chemical parameters (temperature, salinity, dissolved oxygen, particulate organic carbon (POC) and nitrogen (PON) and dissolved organic carbon (DOC), chlorophyll-a content, will be measured. During the 2nd year of activity, the study will be continued following the previous time schedule, in order to point out inter-annual variations in the dynamics of organic matter decomposition and nutrient release. During this phase, research activities will dealt with some qualitative features (discrimination, within the bacterioplankton community, of the living and metabolically active component from the inactive one; identification of the algal species responsible for the enzymatic synthesis), in order to improve knowledge of the potentialities played by different microbial populations in organic matter decomposition. As a future perspective of research, experiments in micro- or mesocosms will be planned to verify what found by the field studies. The scientific significance of the proposal relies on the possibility of testing the hypothesis of using the parameter "alkaline phosphatase" alone or in association with another microbial (or environmental) parameter as a potential biomarker for monitoring the health status of marine and freshwater water bodies and early detecting the occurrence of algal blooms due to P excess.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
