38
4 Management and Conservation of Marine Life
nutrient input, oxygen content, and ocean acidification (Rijnsdorp et al. 2009;
Doney et al. 2012). Several of these forcing mechanisms are responsible for the
formation and permanence of fronts, and define main frontal properties, with wide
ranging biological effects. Ocean temperature will follow increases in air temperature, although to a lesser extent, owing to the high heat capacity of seawater. Shallow areas will exhibit larger temperature increases than deeper waters.
Stratification (resulting from the interplay between temperature and wind mixing)
will also be an important factor in all regions, owing to the effect of stratification
on the vertical fluxes of nutrients and organic matter and consequently on bottomup processes. Changes in wind speed and direction not only influence mixing
and water circulation in the open ocean, but also affect the strength of upwellings
within shelf and coastal regions (Rijnsdorp et al. 2009). Alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment will
affect estuarine productivity. Changes in freshwater flux will affect stratification of
coastal waters impacting also vertical nutrient flux (Scavia et al. 2002). Variations
in the intensity of all these forcing mechanisms will affect key ecological processes of fronts like biological production, retention of plankton, concentration
and aggregation of inert materials, bentho-pelagic coupling, etc.
One of the most conspicuous signs of climate change have been recent changes
in the seasonal timing (phenology) of life history events (Thackeray et al. 2010).
Species-specific variation in phenological responses to climate can disrupt the synchrony of ecological interactions and potentially affect community persistence.
The majority of spring and summer events have advanced, and across environments advances in timing were slowest for secondary consumers, thus increasing
the potential risk of temporal mismatch in key trophic interactions; consequently
future climate warming may exacerbate trophic mismatching, further disrupting the functioning, persistence and resilience of many ecosystems (Thackeray
et al. 2010). In seasonal fronts (e.g. tidal fronts), or permanent fronts exhibiting
seasonal signals (e.g. estuarine fronts), variations in the seasonality (not only
intensity) of forcing could reduce synchrony between frontal patterns and key
biological processes (feeding; reproduction) aggravating disruption of the ecosystems’ functioning.
Because fronts depend on different forcing processes it is expected that the consequences and speed of climate change vary among frontal types; moreover the
effects of climate change are expected to differ in both magnitude and direction
among geographic areas (Rijnsdorp et al. 2009) so features of the same type of
front could be enhanced in one region and weakened in another.
A matter linking climate change and trophic webs at fronts is CO 2 sequestration. The ocean’s storage of carbon and ability to regulate atmospheric carbon dioxide is crucially dependent on primary production; that is the creation of
organic matter from inorganic nutrients and carbon through photosynthesis. The
photosynthesis predominantly utilizes CO 2 dissolved in seawater and so provides
a sink for atmospheric CO 2 when organic carbon is transferred to deeper water.
The transport of limiting nutrients to the sunlit surface ocean (the euphotic zone)
plays a central role in controlling primary production. Moreover, vertical fluxes
4 Management and Conservation of Marine Life
nutrient input, oxygen content, and ocean acidification (Rijnsdorp et al. 2009;
Doney et al. 2012). Several of these forcing mechanisms are responsible for the
formation and permanence of fronts, and define main frontal properties, with wide
ranging biological effects. Ocean temperature will follow increases in air temperature, although to a lesser extent, owing to the high heat capacity of seawater. Shallow areas will exhibit larger temperature increases than deeper waters.
Stratification (resulting from the interplay between temperature and wind mixing)
will also be an important factor in all regions, owing to the effect of stratification
on the vertical fluxes of nutrients and organic matter and consequently on bottomup processes. Changes in wind speed and direction not only influence mixing
and water circulation in the open ocean, but also affect the strength of upwellings
within shelf and coastal regions (Rijnsdorp et al. 2009). Alterations in precipitation patterns and subsequent delivery of freshwater, nutrients, and sediment will
affect estuarine productivity. Changes in freshwater flux will affect stratification of
coastal waters impacting also vertical nutrient flux (Scavia et al. 2002). Variations
in the intensity of all these forcing mechanisms will affect key ecological processes of fronts like biological production, retention of plankton, concentration
and aggregation of inert materials, bentho-pelagic coupling, etc.
One of the most conspicuous signs of climate change have been recent changes
in the seasonal timing (phenology) of life history events (Thackeray et al. 2010).
Species-specific variation in phenological responses to climate can disrupt the synchrony of ecological interactions and potentially affect community persistence.
The majority of spring and summer events have advanced, and across environments advances in timing were slowest for secondary consumers, thus increasing
the potential risk of temporal mismatch in key trophic interactions; consequently
future climate warming may exacerbate trophic mismatching, further disrupting the functioning, persistence and resilience of many ecosystems (Thackeray
et al. 2010). In seasonal fronts (e.g. tidal fronts), or permanent fronts exhibiting
seasonal signals (e.g. estuarine fronts), variations in the seasonality (not only
intensity) of forcing could reduce synchrony between frontal patterns and key
biological processes (feeding; reproduction) aggravating disruption of the ecosystems’ functioning.
Because fronts depend on different forcing processes it is expected that the consequences and speed of climate change vary among frontal types; moreover the
effects of climate change are expected to differ in both magnitude and direction
among geographic areas (Rijnsdorp et al. 2009) so features of the same type of
front could be enhanced in one region and weakened in another.
A matter linking climate change and trophic webs at fronts is CO 2 sequestration. The ocean’s storage of carbon and ability to regulate atmospheric carbon dioxide is crucially dependent on primary production; that is the creation of
organic matter from inorganic nutrients and carbon through photosynthesis. The
photosynthesis predominantly utilizes CO 2 dissolved in seawater and so provides
a sink for atmospheric CO 2 when organic carbon is transferred to deeper water.
The transport of limiting nutrients to the sunlit surface ocean (the euphotic zone)
plays a central role in controlling primary production. Moreover, vertical fluxes