algal bloom
mass development of microscopic algae over large areas of water that
drastically reduces transparency and sometimes also creates surface scum and odors;
some such blooms, created by so-called harmful algae, may be toxic for marine
organisms and poisonous to people
atmospheric loading
man-made inputs of nitrogen to the atmosphere caused by emissions of
nitrogen oxides from combustion of fossil fuels in factories and power stations,
combustion of fuel in transportation, combustion of biomass, and evaporation of
ammonia from manure on farms; the atmospheric contribution consists of wet
(gaseous) and dry (particulate) depositions, which together constitute the total
deposition of an element
biological N2-fixation
the microbial process in which nitrogen gas is transformed into
bioavailable N; important nitrogen fixers are blue-green algae
BOD –
biochemical (biological) oxygen demand
the amount of oxygen used in biochemical and microbiological activity,
usually measured for 5 days; used as an index of pollution of waters with
organic compounds
computer modelling
mathematical modelling of processes, e.g. pollution processes, to better
identify and understand the process of pollution, to predict future developments
and identify the key measures needed to control pollution; the processes studied
are often very complex and composed of a number of partial processes in complex
interaction; a pollutant is described as distributed through a system of several
sub-compartments, where it undergoes various changes in each such
sub-compartment
denitrification
a bacterial processes, occurring in anoxic conditions, i.e. in bottom
waters, in which nitrates (NO3-) are converted to nitrogen gas (N2) which is
released to the atmosphere
diatoms
mostly unicellular microscopic algae (Bacillariophyta) with a
doubled cell wall built with silica; Si:DIN refers to the ratio of silica
concentration to the number of diatoms
ecotone
an edge, often species-rich transition zone between different
ecosystems, either natural, i.e. between a river and land or constructed, e.g.
bushes left between cultivated fields
eutrophication
process causing a significant increase of plant matter in water or on
land due to a high load of nutrients from antropogenic sources, which results in
excessive bacterial growth and strong oxygen depletion; land eutrophication,
especially due to a high load of nitrogen, causes a change of flora from species
adapted to poor soils to those adapted to nutrient-rich soils (often much larger
species)
external loading
release of nutrients from external sources
fertilizer
mixture of nutrients, especially N, P and K (potassium) used in
cultivation of crops
Haber Bosch process
an industrial technology for fixation of atmospheric nitrogen, reducing
nitrogen to ammonia, powered by large amounts of fossil fuel; industrial
fixation of atmospheric nitrogen is today of the same size as biological
nitrogen fixation
internal loading
release of nutrients, mostly phosphorous, from the bottom sediments in
lakes and the sea; internal loading may occur under anoxic conditions in
deepwater and on shallow, eutrophied bottoms at high summer temperatures
nitrates (NO3-)
salt of the nitric acid which is highly soluble; one of the most
important constituents of fertilisers, leachates containing nitrates lead to
eutrophication of water systems
limiting nutrient
nutrient limiting plant growth, which can cause eutrophication if added;
most often nitrogen and phosphorus is limiting, but silica and trace metals may
also be limiting
macro-nutrients
elements or nutrients necessary for growth in larger amounts;
macro-nutrients include some metals - calcium, magnesium, potassium - the
metalloid silicon, and the non-metals sulphur, nitrogen, and phosphorus
manure
faeces and urine from animals
micro-nutrients
elements necessary for growth in very small amounts; micro-nutrients
include the trace metals, principally copper, iron, and zinc, as well as the
non-metals boron, manganese, and selenium
mineralization
microbial activities in the soil occurring when air gets access to soil and
nutrients bound to organic substances are released
nitrification
a bacterial processes in which, in aerobic conditions, ammonia (NH3)
is oxidized to nitrite (NO2-) and nitrate (NO3-).
nitrites (NO2-)
salt of nitrous acid, highly soluble, easily oxidized to nitrates
NOx, nitrous oxides
a mixtures of oxides of nitrogen produced in combustion of fuel with air
in power plants and car traffic; with water in the air nitrous oxides form
strong acids, nitrous acid and nitric acid, which are both eutrophying and
acidifying
nutrients
organic and inorganic chemical compounds or elements necessary in various
amounts to support normal living processes
Redfield value
ratio of nitrogen to phosphorus roughly describing the algal consumption
pattern of these elements; in phytoplankton organic matter, there are on average
16 nitrogen atoms for one phosphorus atom, that is the Redfield value is 16 N :
1 P
sewage
waste water and excrement; sewage is a main source of discharges of
nutrients into recipients, such as lakes and rivers
simulation model
semi-empirical model, aimed at a numerical reproduction of all the major
physical, chemical, and biological processes that define a system, for example
biogeochemical fluxes
sludge
residue after sewage treatment where nutrients, especially phosphorus, is
enriched
systems analysis
analysis of a system using computer modelling
turnover rate
movement of nutrients or other chemical compounds in a biogeochemical
cycle calculated from inflow and outflow from a given pool and its quantity
weathering
release of phosphorus from minerals and mineral particles in soil
world model
a systems analysis of the world as a whole, e.g. that published by the
Club of Rome in the classic 1972 report "The Limits to Growth" that
predicts a very bleak future for the world if pollution on the scale then would
continue for about 100 years