Practical of aquatic ecology
Learning outcomes of the course unit
The course is offered to students of the master’s degree and it aims to transfer cultural and practical tools for the analysis of main chemical and physical features (basic parameters) and biogeochemical processes (nutrient cyclization) in inland waters. Particular attention will be paid to the acquisition of practical laboratory skills. At the end of the course, students will be able to work in the field and in a chemical and biological laboratory, in order to identify representative sampling sites, to make correct water and sediment collections, to prepare and analyze samples correctly, to apply different chemical and biological quality indices and to interpret them critically.
Five main training objectives are proposed: 1) acquisition of the basic notions regarding the limnological and biogeochemical tools and approaches to investigate inland water ecosystems; 2) properly prepare the sampling design for different environmental matrices; 3) learn to use field instruments for direct measurements in the environment, and for sampling and pre-treatment of samples; 4) work in a chemical-biological laboratory through the learning of safety regulations, reagent management, application of simple spectrophotometric methods; 5) critically interpret the data provided by analyses.
Course contents summary
The course has the primary objective of describing and acquiring familiarity with the tools and methods useful for the chemical-physical characterization and quantification of the main biogeochemical processes in inland water environments. The course will provide to the students: 1) the scientific references of the biogeochemical processes and actors that regulate the quality of internal aquatic ecosystems (theoretical part), 2) and the sampling and analysis techniques. The student must have as a reference the basis of functioning of aquatic ecosystems and the multiple relationships between environment and organisms. The course has a strong practical/experimental character, and is organized in 6 modules, each of 4 hours, supplemented by field activities, aimed at recovering the materials to be analyzed, review and discussion on the practical activities carried out (12 hours). Module 1: Introduction to the limnologist's field tools; Module 2: Gases of biological interest (oxygen, carbon dioxide, methane); Module 3: Spectrophotometric determination of nutrients (NH4+, SO43-), and photosynthetic pigments (chlorophyll). Module 4: Analysis of metals (Fe and Mn) and atomic absorption methods; Module 5: Nitrate analysis, irrigation loop and determination; Module 6: Microbiological parameters (eg total coliforms, indices for bathing waters).
Module 1: Introduction to the limnologist's field tools and their correct use (e.g. multiparameter probes, Secchi disk, luxmeter, current meter, cores), to a correct sampling of water and sediments, and the definition of a sampling plan for different environmental matrices (criteria for sampling sites selection, for sediment, water, biotic components).
Module 2: Introduction to the processes that regulate the concentrations and dynamics of gases of biological interest in freshwater ecosystems (O2, CO2, CH4). Practical experience of measurement, oxygen titration.
Module 3: Introduction to the processes that regulate the dynamics (sources and transformations) of the main macro-pollutants (N and P) in freshwater ecosystems. Practical experiences of determination (spectrophotometric analysis) of NH4+ and SO43- and of pigments.
Module 4: Introduction to the processes that regulate the dynamics (sources and transformations) of the main metals of biogeochemical interest in freshwater ecosystems (Fe and Mn), both in the water matrix and in the sediments. Practical experiences of determination (atomic absorption analysis) of Fe and Mn.
Module 5: Introduction to the processes that regulate the dynamics of nitrates, with particular reference to their cyclization and the phenomenon of the irrigation loop. Practical experiences of determination of NO3-, and of percolation in contaminated soils.
Module 6: Introduction to microbiological parameters, in particular the so-called “indicator bacteria”, used in determining the quality of water and to define its potability. Practical experiences in determining total coliforms.
Lecture notes are available for students for each module, as well as the official IRSA-CNR handbooks for chemical water analysis methods. The material will be provided by the teacher in electronic format in preparation and during the performance of modules and field activities.
The teaching organization consists of lectures both finalized to introduce theory and practical activities, having as their object the general presentation of the course, the performance of the modules and a final review lesson. The laboratory activities are aimed at the characterization of the abiotic matrices (water and sediment), and to the quantification of the main biogeochemical processes, the field activities are aimed at sampling the different matrices (abiotic and biotic) and the collection of environmental measurements with portable instrumentation (multiprobe).
Assessment methods and criteria
Attendance at lectures, field and laboratory activities is a pre-requisite for being admitted to the final exam, similarly the level of participation in the activities, and the compilation of field and laboratory reports are subject to evaluation by the teacher. A maximum of 25% absences (approx. 1 module) is permitted, only for serious reasons to be justified in an adequate manner by students. The evaluation of participation in the activities contributes 30% of the final grade. At the end of the course, the student must take a test (21 questions) with multiple answers. The mark of the test contributes to 70% of the final grade. The final mark is thirty; the minimum is 18, the maximum 30, the possible praise is assigned only to the students who during the course have actively participated in the workshops and field trips.