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9
Photoautotrophic Productivity in
Eutrophic Ecosystems
Martin T. Dokulil
9.1 Introduction
Eutrophication is the process of increased productivity of
lakes, rivers and estuaries as a consequence of increased
nutrient input from the water shed. The process of eutrophication can be natural but is in most cases a syndrome of
ecosystem responses to human activities in the catchment.
Accordingly, production of plants, bacteria and animals usually increase but the outcome is highly variable. Phytoplankton primary production is strongly influenced by latitude
(Brylinsky and Mann 1973; Boulion 2003), insolation (e.g.
Jónasson 1974; Anderson 1974) and nutrient availability
(e.g. Schindler 1978), but also depends on lake size, the size
of the catchment, the type of water body and lake depth (Fee
1979, 1980; Knoll et al. 2003; Nõges 2009).
Primary production is a fundamental ecological variable.
It is a measure of the extent to which primary energy input
by solar energy to the aquatic environment is transformed
and accumulated into biological entities adding organic
substance to the ecological sphere. Because production is
defined as the flux of inorganic carbon into autotrophic organisms per unit time, this rate can be used as an indicator
of growth and hence as a major criterion to determine the
Abstract
Enhanced photoautotrophic productivity of lakes, reservoirs, rivers and streams is a consequence of prolific nutrient loading from the catchment known as eutrophication. In most
cases, it is a syndrome of ecosystem responses to human activities in the watershed. Primary production is strongly influenced by latitude, insolation and nutrient availability, but
also depends on lake size, the size of the catchment, the type of water body and lake depth.
The outcome is therefore highly variable for specific continental waters. Nevertheless, autotrophic production is perhaps the best parameter to define the trophic level of waters.
The complex techniques and frequent measurements necessary to estimate production accurately hampered the application, however. Recent improvements in methods and new
developments in monitoring strategies have revived interest in primary production as an
index to define trophy. Important relationships of production to environmental variables
are analysed. Then, development of boundary criteria are discussed, production indices
compared and trophic boundary classifications compiled from different authors. Maximum
and global production is emphasised. The impact of a warmer world as a consequence of
climate change on continental waters is highlighted and future perspectives of photoautotrophic production summarised.
Keywords
Productivity · Continental waters · Eutrophication · Trophic indices · WFD
M. T. Dokulil ()
EX Institute for Limnology, Austrian, Academy of Sciences,
Eisenaustrasse 20,
5310 Mondsee, Austria
e-mail: martin.dokulil@oeaw.ac.at
A. A. Ansari, S. S. Gill (eds.), Eutrophication: Causes, Consequences and Control,
DOI 10.1007/978-94-007-7814-6_9, © Springer Science+Business Media Dordrecht 2014
9
Photoautotrophic Productivity in
Eutrophic Ecosystems
Martin T. Dokulil
9.1 Introduction
Eutrophication is the process of increased productivity of
lakes, rivers and estuaries as a consequence of increased
nutrient input from the water shed. The process of eutrophication can be natural but is in most cases a syndrome of
ecosystem responses to human activities in the catchment.
Accordingly, production of plants, bacteria and animals usually increase but the outcome is highly variable. Phytoplankton primary production is strongly influenced by latitude
(Brylinsky and Mann 1973; Boulion 2003), insolation (e.g.
Jónasson 1974; Anderson 1974) and nutrient availability
(e.g. Schindler 1978), but also depends on lake size, the size
of the catchment, the type of water body and lake depth (Fee
1979, 1980; Knoll et al. 2003; Nõges 2009).
Primary production is a fundamental ecological variable.
It is a measure of the extent to which primary energy input
by solar energy to the aquatic environment is transformed
and accumulated into biological entities adding organic
substance to the ecological sphere. Because production is
defined as the flux of inorganic carbon into autotrophic organisms per unit time, this rate can be used as an indicator
of growth and hence as a major criterion to determine the
Abstract
Enhanced photoautotrophic productivity of lakes, reservoirs, rivers and streams is a consequence of prolific nutrient loading from the catchment known as eutrophication. In most
cases, it is a syndrome of ecosystem responses to human activities in the watershed. Primary production is strongly influenced by latitude, insolation and nutrient availability, but
also depends on lake size, the size of the catchment, the type of water body and lake depth.
The outcome is therefore highly variable for specific continental waters. Nevertheless, autotrophic production is perhaps the best parameter to define the trophic level of waters.
The complex techniques and frequent measurements necessary to estimate production accurately hampered the application, however. Recent improvements in methods and new
developments in monitoring strategies have revived interest in primary production as an
index to define trophy. Important relationships of production to environmental variables
are analysed. Then, development of boundary criteria are discussed, production indices
compared and trophic boundary classifications compiled from different authors. Maximum
and global production is emphasised. The impact of a warmer world as a consequence of
climate change on continental waters is highlighted and future perspectives of photoautotrophic production summarised.
Keywords
Productivity · Continental waters · Eutrophication · Trophic indices · WFD
M. T. Dokulil ()
EX Institute for Limnology, Austrian, Academy of Sciences,
Eisenaustrasse 20,
5310 Mondsee, Austria
e-mail: martin.dokulil@oeaw.ac.at
A. A. Ansari, S. S. Gill (eds.), Eutrophication: Causes, Consequences and Control,
DOI 10.1007/978-94-007-7814-6_9, © Springer Science+Business Media Dordrecht 2014