Module Information

Module Identifier
Module Title
Freshwater Biology
Academic Year
Semester 2
External Examiners
  • Dr Martin Genner (Senior Lecturer - University of Bristol)
Other Staff

Course Delivery

Delivery Type Delivery length / details
Practical 6 x 4 Hour Practicals
Lecture 33 x 1 Hour Lectures


Assessment Type Assessment length / details Proportion
Semester Exam 2 Hours   60%
Semester Assessment Practical write-up  including data analysis, data presentation and discussion (expected limit max. 1500 words)  25%
Semester Assessment Practical exam  15%
Supplementary Exam 2 Hours   Students must take elements of assessment equivalent to those that led to failure of the module  60%
Supplementary Assessment Coursework. Students must take elements of assessment equivalent to those that led to failure of the module  40%

Learning Outcomes

On successful completion of this module students should be able to:

1. Demonstrate an understanding of freshwater ecosystems and their biological communities

2. Explain the processes which control the functioning of lake and river ecosystems

3. Describe the factors that affect the population dynamics of organisms in the freshwater environment

4. Demonstrate skills in data collection, analysis and interpretation of data when sampling the freshwater environment

5. Identify the principal groups of freshwater invertebrates and demonstrate an understanding of functional classification

Brief description

This module aims to introduce students to the organisms and processes that characterise freshwater ecosystems, through an integrated series of lectures and practical classes. It covers a range of freshwater habitats from the smallest rivers to the largest lakes, and a range of organisms from viruses to vertebrates and how these groups interact. It also takes account of the impact of human activity on all of these.


1. Demonstrate an understanding of freshwater ecosystems and their biological communities
2. Explain the processes which control the functioning of lake and river ecosystems
3. Identify the principal groups of freshwater invertebrates
4. Describe the factors (abiotic and biotic) that affect the population dynamics of organisms in the freshwater environment.


The module assumes no prior knowledge of inland waters, although some students may have a little background from physical geography or from field work undertaken at school or college.

The lecture series starts with an overview of the freshwater environment, including a global perspective of habitat types and biota. It covers the structural aspects of freshwater systems, including the origin of lakes and drainage systems, and physical habitat characteristics at a variety of spatial and temporal scales in lakes and rivers, and an overview of the freshwater biota and its adaptations to the medium. Following lectures focus primarily on temperate freshwater environments as most relevant to our location. Abiotic factors that affect freshwater systems, including temperature, light and biogeochemical cycles are introduced, including factors determining the availability and chemistry of water in inland drainage.
The section on lake biology includes a review of primary producers and their principal characteristics. It covers seasonal variation in relation to stratification, the role of the microbial and bacterial/viral loops. The section also deals with zooplankton, their place in open water trophic webs, including competition, bottom-up and top-down controls on the functioning of open water systems. It concludes with the biology of the benthos, including macrophytes.

In dealing with river systems, the theme is the spatial pattern imposed by changing conditions from the headwater to the estuary. Relationships between physical conditions and biological assemblages are described, together with the role of biotic interactions in determining the structure of stream invertebrate assemblages. Physical disturbance is discussed as is the concept of patch dynamics at a variety of spatial scales. A section on the dynamics of organic matter in streams provides a link with the section on lakes. Vertebrate assemblages in freshwater systems and the longitudinal zonation of vertebrates along European rivers are described in relation to abiotic factors.

The final section of the course deals with human impacts, paying particular attention to freshwater pollutants. Examination of methods of monitoring water quality and methods used to prevent or restore affected freshwater systems are discussed.
The practical classes are based on investigation of the invertebrate communities of a local river and the littoral habitat of a small lake. These provide experience of simple techniques for sampling in the field and handling and preserving material in the lab, serving to illustrate many of the topics covered in the preceding lectures.

One practical spread over five slots. The sequence of sessions is weather dependent; sessions 3 & 4 may be moved to precede 1 & 2.

1. Introduction to river invertebrates. Field trip: sampling R.Ystwyth; physical factors, sediment, benthos. Sorting invertebrates and preparing sediment for analysis. KY
2. Laboratory analysis of river material. Identification and quantification of organisms. Particle size analysis of sediment. Logging of data. KY/SD
3. Introduction to lake fauna. Field trip: sampling Pond yr Oerfa. Sorting invertebrates. SD
4. Laboratory analysis of lake material. Identification and quantification of organisms. Logging of data. SD/KY
5. Synthesis and discussion of data from sessions 1-4. Revision of identification from class collection of material. SD/KY

Practical exam (invertebrate identification and functional classification)

Module Skills

Skills Type Skills details
Application of Number It is expected that students will conduct statistical analyses of data collected in practicals.
Communication Students will produce a report on the laboratory practicals which will require them to develop good skills in effective science communication. This will be assessed through the laboratory practical report.
Improving own Learning and Performance Not a significant component of assessment in this module. However, students will be provided with feedback on assessed exercises. They will also engage in self-testing of taxonomic skills in the final practical session.
Information Technology It is expected that students will word process reports, use spreadsheet programs to handle data and graph findings, and statistical programs to analyse data. The correct application of this technology will be assessed via practical reports.
Personal Development and Career planning Students will be made aware of the practical skills they are using in sampling methodology and invertebrate identification would be relevant to future employment in environmental assessment and research.
Problem solving Not a significant component of the module, though students will be encouraged to consider problems that arise in relation to environmental sampling and data collection during the practical elements of the module.
Research skills Students will be required to engage with the peer-reviewed research literature and this will require effective use of scientific search engines, and critical reading and appraisal of scientific papers. Effective use of the peer-reviewed literature will be assessed via the practical report and examination. Research skills will be developed through introduction and application of basic methods of data collection.
Subject Specific Skills Use of keys and species identification of freshwater invertebrates, developed during the practical and assessed in the practical exam.
Team work Students will be expected to work in teams to carry out sampling and sorting of practical material. They will be expected to work as a team to complete these elements, balancing the work load amongst members of the team. Assessment will be on individual work.


This module is at CQFW Level 5