Newsletter and Technical Publications
Freshwater Management Series No. 5
Guidelines for the Integrated Management of
- Phytotechnology and Ecohydrology -
AND MOST COMMONLY USED SYMBOLS AND ABBREVIATIONS
Aerobes - organisms, which can
live only in aerobic conditions as they gain energy from the process of respiration.
Aggregation - the process of
combining smaller spatial units in to larger sets.
Algae- microscopic, usually unicellar, plants.
Allochthonous - brought into a waterbody from outside.
Allochthonous organic matter - organic matter transported into a lake or river from adjacent ecosystems.
Anaerobes - organisms living in
anaerobic conditions and gaining energy from chemical reactions which are not
based on oxygen transformations.
Analogue map - map printed on a
paper using graphic symbols to represent features and values.
Arc - a line consisting of series of vertices.
Attribute - an alphanumeric
characteristic of a geographic object (point, line, area) that can be stored in
a relational data base and linked by an identifier to an object.
Autochthonous - produced within the waterbody
Biological survey (Biosurvey) - the process of
collecting and processing representative portions of a resident aquatic
community to determine the community membership, structure, and functions.
Biological assessment (Bioassessment) - an evaluation of
the biological condition of a waterbody through the use of biosurveys and other
direct measurements of resident biota in surface waters.
Biological monitoring (Biomonitoring) - the use of a
biological entity as a detector, and its response as a measure, to determine
environmental conditions. Biosurveys and toxicity tests are common
Biological criteria (Biocriteria) - numeric values or
narrative expressions that describe the reference biological conditions of
aquatic communities inhabiting waters that have been given a designated aquatic
Biomanipulation - an inclusive
term for methods of changing the biological structure of an ecosystem in order
to improve water quality.
Biomass - the quantity of living organisms expressed
in units of volume or mass, generally related to a unit of volume or area
within a waterbody.
Biotope - populations of all species living in particular space.
Blooms - high concentrations of phytoplankton biomass
Buffer - a zone of given radius
around a geographical object (point, line, area).
Cartesian coordinate system - a
system of two or three mutually perpendicular axes along which the location of
any point can be precisely described by a set of (x,y,z) coordinates.
Carrying capacity - the dynamic
equilibrium around which a population fluctuates; regulated by available space
and the amount (and quality) of the available resources.
Cascade effect - the transmission of changes within a given trophic level
to lower trophic levels.
Contour - a line connecting
points of equal elevation (or other attribute).
Cyanobacteria [also Cyanophytes
or blue-green algae] - a group of phytoplankton, some of which can produce
toxins, regulate their depth using a gas-vacuole buoyancy mechanism, and/or fix
atmospheric nitrogen for use in growth. They often occur in eutrophic waters as
Data - the basic element of
information that can be processed by a computer; may be alphanumeric or
Data model - a formal method of
arranging data to represent the observed environment.
Database - a computer file
containing data, organized, inter alia,
as a set of tables or coordinates of the points and their attendant attributes.
Denitrification - the
microbiologically-mediated reduction of oxygenated nitrogen compounds to
Denitrifying bacteria - the group of bacteria which utilise nitrate
in one of three metabolic pathways: a) without accumulating nitrite, b) with
transient accumulation of nitrite, and c) in a two-step denitrification process
that transforms nitrate into gaseous nitrogen.
Diatoms [also Bacillariophytes]-
a group of algae with siliceous walls.
Digital Terrain Model (DTM) - data which depict the relief of given area of terrain using a grid or irregular
triangular network and contour elevations.
Digitise - a means of entering
geographical data into computerised data basesfrom analogue maps.
Dinoflagellates - a group
of phytoplankton with flagella, or whip-like appendages, by which the organisms
have limited movement.
Diversity of fish - the proportion of a given fish
species within a sample population. Diversity may be calculated using the
Shannon Index (H), where: H' = ∑pi lnpi . pi
is the ratio of each component (the % of a given species) to
the total value (all species=100%). The index may be scaled from 0 to 1, where
0 is the lowest possible diversity and 1 is the maximum possible diversity by
dividing H' by lnS, where S is the number of species having the indicated pi
value (after Odum 1980).
Ecological integrity - the condition of the biotic
(aquatic community) and abiotic (water chemistry and habitat) components of
unimpaired waterbodies, as measured by assemblage structure and function, water
chemistry, and habitat measures.
Ecoregions - a relatively homogeneous area defined by the similarity of
climate, landform, soil, potential natural vegetation, hydrology, or other
ecologically relevant variable.
Ecotone - the transition zone between two
different types of ecosystems, such as a river and a meadow, characterised by
very high biodiversity; ecotones may play an important role as buffers, modifying
and limiting flows of nutrients and pollutants between ecosystem components.
Entity - a discrete geographical
object represented as a digital data structure.
Feature - a representation of a
geographical object as a point, line, or polygon.
Filter - a small matrix (mask)
containing coefficients used for modifying pixel values in a raster image on a
map, using a variety of mathematical procedures.
Fluorescence - the process
whereby light is absorbed at one wavelength and almost instantaneously emitted
at new and longer wavelength by an organic molecule, as in the case of
Generalization - the reduction
of the volume of geographical data; such reductions are usually used to
construct a better graphical representation on a map or in image enhancement.
Geographic object - a
user-defined part of the real world that can be represented using geographical
features and attributes.
Georeference - the relationship
between raster data and cartographic coordinates.
Grid data - the structure of
data used to represent geographical objects, composed of square cells of equal
area, arranged in rows and columns.
Green algae [ also Chlorophytes] - a group of algae which are usually
a good food for zooplankton.
Image - a graphic representation
of an object produced by an optical or electronic device. An image is stored as
raster data in the form of pixel values.
Interpolation - making
predictions based on measurements done only in a certain area.
In vivo - in living organisms.