Environmental Engineering Reference
In-Depth Information
of ecosystem functions (Richardson 2008). One of the most important roles
of zooplankton is as the major grazers in ocean food webs, providing the
main pathway for energy from primary producers to consumers (Richardson
2008). Consequently, climate-induced changes on pelagic ecosystems
are effectively transferred by zooplankton to upper trophic levels as
commercially important fi sh populations (Mollman et al. 2008). The goal
of this chapter is to summarize the observed and potential future responses
of zooplankton communities to climate change. It focuses mainly on the
effects that global warming, ocean acidifi cation and UV radiation have on
zooplankton communities.
Zooplankton as Indicator of Climate Change
The observed climate modifi cations in the last decades have led to an
increased effort on monitoring the environmental conditions of aquatic
ecosystems. The detection of sentinel organisms may provide an early
warning of climate-related environmental degradation. Zooplanktonic
organisms are particularly valuable bioindicators of climate-driven change
in marine environments, since they present various particular attributes:
• They are poikilothermic, so their physiological processes (e.g.,
ingestion, respiration, reproduction) are highly sensitive to changes
in temperature.
• Zooplanktonic species have a short life cycle; therefore, population
size is less infl uenced by the persistence of individuals from previous
years (Richardson and Kunz 2006). This leads to a close connection
between environmental changes and population dynamics (Richardson
2008).
• Few species of zooplankton are commercially exploited; consequently,
any long-term variation in response to environmental change is
generally not confounded with trends in exploitation (Richardson
2008).
• Zooplanktonic organisms are better indicators of change than
environmental variables themselves, because the non-linear responses
of the organisms can amplify environmental perturbations (Taylor et
al. 2002).
• Considering their free floating habits, zooplankton can show
dramatic changes in distribution and may respond easily to changes
in temperature and oceanic currents by expanding/contracting their
distributional ranges (Richardson and Kunz 2006).
