37
3 Effects of Eutrophication
coralline algae, the important coral reef builders (Björk et al.
1995).
Increasing sediment load caused by eutrophication can
cause pronounced changes in the environmental characteristics of coral reef ecosystems (Rogers 1990), and affect
growth rates, reproduction, and community structure of
scleractinian corals (Tomascik and Sander 1987b). In addition, eutrophication may negatively effect on coral reefs
through some trophic relations between various flora and
fauna. In some regions of the Great Barrier Reef lagoon, eutrophication-induced algal overgrowth promoted outbreaks
of the crown of thorns starfish, the active predator of coral
recruitment (Fabricius et al. 2010). Sedimentation by algal
growth decreased the available light and caused a decline
in the hermatypic reef corals (Tomascik and Sander 1987a;
Rogers 1990), while macroalgal bloom can inhibit reef coral
growth and recruitment (Smith et al. 1981), leading to loss of
coral cover in eutrophic tropical hard-bottom communities
(Lapointe and Clark 1992)
3.4.5 Effect on Zooplankton
The effects of increasing eutrophication on the crustacean
zooplankton composition have been reported in many marine
habitats worldwide. These effects appeared in species diversity, community structure, size, reproduction rate, and feeding habits. Owing to its wide array of diversity zooplankton
community demonstrates variable and sometimes contradictory trends in responses to eutrophication (Hulot et al. 2000)
whereas intensive eutrophication may lead to a significant
increase in the number of zooplankton species, disappearance of some species, and marked increase of abundance
(Ostoijc 2000). In addition, significant changes were reported in the species diversity indices (Kozuharov et al. 2007) in
dominant species and alteration of zooplankton species diversity and succession (Park and Marshall 2000). However,
eutrophication may cause a decline in species richness and in
the abundance of zooplankton (Sendacz et al. 2006) and an
increase of large-sized phytoplankton forms (Breitburg et al.
1999), which provide better feeding conditions for the copepods (Hansen et al. 2000)
The variation in the loads of dissolved inorganic nitrogen (DIN) and inorganic phosphorus appeared to have a
role in the changes of zooplanktoin community structure.
The total mesozooplankton biomass as well as copepod and
cladoceran biomass decreased with DIN, while both groups
increased with the dissolved inorganics phosphorous (DIP)
load (Zervoudaki et al. 2009). Opposite correlations were
observed between zooplankton abundance and DIN (decrease) and DIP (increase) in the highly eutrophic tributaries of Chesapeake Bay (Park and Marshall 2000). However,
protozooplankton (ciliates and heterotrophic dinoflagellates)
biomass did not show any response to the enhanced nutrients
(Zervoudaki et al. 2009).
In the Belgian Coastal Zone and the Southern Bight of
the North Sea, the predominant colonial haptophyte Phaeocystis globosa (Muylaert et al. 2006) negatively impacted
the dynamics and life cycles of zooplankton (Lancelot and
Rousseau 1994, Lancelot et al. 2002) such as the nauplii and
copepodites I–V of the copepod Temora longicornis (Daro
et al. 2006), which may be attributed to the thick gelatinous
sheet surrounding the Phaeocystis colonies and/or its poor
nutritional value (Tang et al. 2002).
Eutrophication may impact zooplankton size (MatsumuraTundisi 1999) as reported in the Pampulha reservoir, Brazil,
where zooplankton suffered extensive qualitative and quantitative changes, particularly in size and biomass of certain
zooplankton groups owing to the replacement of small cladocerans such as Bosmina and Ceriodaphnia by another
relatively large cladoceran, Moina micrura (Pinto-Coelho
et al. 2005). A strong relationship between total phosphorus
and particulate organic carbon may be responsible for such
variations, owing to the relative importance of the detrital
food chain for the planktonic community in the Pampulha
reservoir (Pinto-Coelho et al. 2005) which in turn may affect the balance between primary and secondary production
(Araújo Araujo and Pinto-Coelho 1998). A significant linear
regression observed between biomass of zooplankton and/
or certain groups (e.g., cyclopoids) and total phosphorus
suggests that the response of zooplankton to eutrophication
achieved through the intensive growth of one of the major
groups (Pinto-Coelho et al. 2005). However, no similar relationship reported between phosphorous and other crustacean
zooplankton groups such as cladocerans and calanoids eutrophic waters (Pinto-Coelho et al. 2005) may be owing to
the disappearance of the dominant zooplankters, like Daphnia (Pinto-Coelho et al. 2003) or disappearance of calanoids
from these waters (Sendacz 1984).
The impact of eutrophication on the structure of zooplankton community is also related to the effect of other
trophic levels, such as primary producers and fishes. For example, intensive growth of the macrophyte water hyacinth
(Eichhornia crassipes) in eutrophic lake is accompanied
with harmful mosquito propagation, the removal of which
requires intensive removal of the hyacinth (Pinto-Coelho
et al. 2005). This in turn causes ammonium decrease, nitrate
increase, and a pronounced change in zooplankton community structure, such as the disappearance of the calanoid
Scolodiaptomus corderoi, and the smaller cladocerans Bosmina and Ceriodaphnia (Pinto-Coelho and Araújo 1997). In
addition, the macrophyte removal may enhance some bacterial bloom, such as the cyanobacteria Microcystis spp., which
has a crucial role in the temporal patterns of major biochemical properties of the seston (Boechat 2000) and play a key
role in the overall metabolism of phytoplankton, seston, and
3 Effects of Eutrophication
coralline algae, the important coral reef builders (Björk et al.
1995).
Increasing sediment load caused by eutrophication can
cause pronounced changes in the environmental characteristics of coral reef ecosystems (Rogers 1990), and affect
growth rates, reproduction, and community structure of
scleractinian corals (Tomascik and Sander 1987b). In addition, eutrophication may negatively effect on coral reefs
through some trophic relations between various flora and
fauna. In some regions of the Great Barrier Reef lagoon, eutrophication-induced algal overgrowth promoted outbreaks
of the crown of thorns starfish, the active predator of coral
recruitment (Fabricius et al. 2010). Sedimentation by algal
growth decreased the available light and caused a decline
in the hermatypic reef corals (Tomascik and Sander 1987a;
Rogers 1990), while macroalgal bloom can inhibit reef coral
growth and recruitment (Smith et al. 1981), leading to loss of
coral cover in eutrophic tropical hard-bottom communities
(Lapointe and Clark 1992)
3.4.5 Effect on Zooplankton
The effects of increasing eutrophication on the crustacean
zooplankton composition have been reported in many marine
habitats worldwide. These effects appeared in species diversity, community structure, size, reproduction rate, and feeding habits. Owing to its wide array of diversity zooplankton
community demonstrates variable and sometimes contradictory trends in responses to eutrophication (Hulot et al. 2000)
whereas intensive eutrophication may lead to a significant
increase in the number of zooplankton species, disappearance of some species, and marked increase of abundance
(Ostoijc 2000). In addition, significant changes were reported in the species diversity indices (Kozuharov et al. 2007) in
dominant species and alteration of zooplankton species diversity and succession (Park and Marshall 2000). However,
eutrophication may cause a decline in species richness and in
the abundance of zooplankton (Sendacz et al. 2006) and an
increase of large-sized phytoplankton forms (Breitburg et al.
1999), which provide better feeding conditions for the copepods (Hansen et al. 2000)
The variation in the loads of dissolved inorganic nitrogen (DIN) and inorganic phosphorus appeared to have a
role in the changes of zooplanktoin community structure.
The total mesozooplankton biomass as well as copepod and
cladoceran biomass decreased with DIN, while both groups
increased with the dissolved inorganics phosphorous (DIP)
load (Zervoudaki et al. 2009). Opposite correlations were
observed between zooplankton abundance and DIN (decrease) and DIP (increase) in the highly eutrophic tributaries of Chesapeake Bay (Park and Marshall 2000). However,
protozooplankton (ciliates and heterotrophic dinoflagellates)
biomass did not show any response to the enhanced nutrients
(Zervoudaki et al. 2009).
In the Belgian Coastal Zone and the Southern Bight of
the North Sea, the predominant colonial haptophyte Phaeocystis globosa (Muylaert et al. 2006) negatively impacted
the dynamics and life cycles of zooplankton (Lancelot and
Rousseau 1994, Lancelot et al. 2002) such as the nauplii and
copepodites I–V of the copepod Temora longicornis (Daro
et al. 2006), which may be attributed to the thick gelatinous
sheet surrounding the Phaeocystis colonies and/or its poor
nutritional value (Tang et al. 2002).
Eutrophication may impact zooplankton size (MatsumuraTundisi 1999) as reported in the Pampulha reservoir, Brazil,
where zooplankton suffered extensive qualitative and quantitative changes, particularly in size and biomass of certain
zooplankton groups owing to the replacement of small cladocerans such as Bosmina and Ceriodaphnia by another
relatively large cladoceran, Moina micrura (Pinto-Coelho
et al. 2005). A strong relationship between total phosphorus
and particulate organic carbon may be responsible for such
variations, owing to the relative importance of the detrital
food chain for the planktonic community in the Pampulha
reservoir (Pinto-Coelho et al. 2005) which in turn may affect the balance between primary and secondary production
(Araújo Araujo and Pinto-Coelho 1998). A significant linear
regression observed between biomass of zooplankton and/
or certain groups (e.g., cyclopoids) and total phosphorus
suggests that the response of zooplankton to eutrophication
achieved through the intensive growth of one of the major
groups (Pinto-Coelho et al. 2005). However, no similar relationship reported between phosphorous and other crustacean
zooplankton groups such as cladocerans and calanoids eutrophic waters (Pinto-Coelho et al. 2005) may be owing to
the disappearance of the dominant zooplankters, like Daphnia (Pinto-Coelho et al. 2003) or disappearance of calanoids
from these waters (Sendacz 1984).
The impact of eutrophication on the structure of zooplankton community is also related to the effect of other
trophic levels, such as primary producers and fishes. For example, intensive growth of the macrophyte water hyacinth
(Eichhornia crassipes) in eutrophic lake is accompanied
with harmful mosquito propagation, the removal of which
requires intensive removal of the hyacinth (Pinto-Coelho
et al. 2005). This in turn causes ammonium decrease, nitrate
increase, and a pronounced change in zooplankton community structure, such as the disappearance of the calanoid
Scolodiaptomus corderoi, and the smaller cladocerans Bosmina and Ceriodaphnia (Pinto-Coelho and Araújo 1997). In
addition, the macrophyte removal may enhance some bacterial bloom, such as the cyanobacteria Microcystis spp., which
has a crucial role in the temporal patterns of major biochemical properties of the seston (Boechat 2000) and play a key
role in the overall metabolism of phytoplankton, seston, and