493
microplastic contamination and exportation (Chen 2015; Costa and Barletta 2015,
2016). But efforts to prevent are still in slow course.
Uncontrolled and synergetic human-driven changes in estuarine water quality
might leave these systems increasingly vulnerable to global changes. Increasing
water temperature impairs dissolved oxygen levels in the water column. Intense El
Niño southern oscillations (ENSO) for example, may cause more severe, frequent
and lasting climatic disturbances, resulting in longer dry seasons and/or excessive
rainfall and river flushes (Ríos-Pulgarín et al. 2016) from which estuarine systems
will find more and more difficult to recover if they have to face it under already
precarious water quality conditions.
Despite all impacts, climate and hydrodynamics of western Atlantic estuaries
contribute to reduce pollution, especially during the rainy season, through biodilution and transport of contaminants out of the system, in a process known as environmental homeostasis (Dyke and Weaver 2013; Elliott and Quintino 2007) (Figs. 16.7
and 16.8). In estuaries with larger river basins and which are more environmentally
variable, such as Caeté and Paranaguá, unless severe, anthropogenic interventions
are more difficult to detected (Barletta et al. 2016; Monteiro et al. 2011). However,
the capacity of Goiana Estuary to withstand modifications is still a hesitation, since
it is located in a short, low discharge, river basin only hundreds of km long and,
therefore, the freshwater influence is small trough most part of the year (Lima et al.
2016).
16.3.3 Implications for the Conservation of Western Atlantic
Estuaries
The connectivity among river basin, coastal zones and coastal waters promoted by
estuarine gradients (ecocline) is currently widely discussed in the scientific literature (Able 2005; Barletta and Blaber 2007; Barletta et al. 2010; Watanabe et al.
2014), and estuaries are well known as important areas for providing biological and
geochemical demands to other environments (Costa and Barletta 2016). These well
established environmental processes need to face a mighty contender, that is intense
societal and economic use and occupation. Estuaries are in coastal zones where
population density is highest, pressures of agricultural and industrial expansion,
improper disposal of wastes and sewages significantly alter natural environments,
water quantities and quality, upsetting local and regional biogeochemical processes,
flora and fauna (Barletta et al. 2010). Therefore, managerial plans should aim at
improve resilience before the modifications experienced by these ecosystems overpass their services capacity (Williams and Crutzen 2013). To support estuarine and
coastal management in an adaptive way, there are robust sampling designs that can
provide consistent ecological and statistically testable data (Kurup et al. 1998;
Worm et al. 2009; Blaber and Barletta 2016; Reis et al. 2016).
16 Estuarine Ecoclines and the Associated Fauna: Ecological Information as the Basis…
microplastic contamination and exportation (Chen 2015; Costa and Barletta 2015,
2016). But efforts to prevent are still in slow course.
Uncontrolled and synergetic human-driven changes in estuarine water quality
might leave these systems increasingly vulnerable to global changes. Increasing
water temperature impairs dissolved oxygen levels in the water column. Intense El
Niño southern oscillations (ENSO) for example, may cause more severe, frequent
and lasting climatic disturbances, resulting in longer dry seasons and/or excessive
rainfall and river flushes (Ríos-Pulgarín et al. 2016) from which estuarine systems
will find more and more difficult to recover if they have to face it under already
precarious water quality conditions.
Despite all impacts, climate and hydrodynamics of western Atlantic estuaries
contribute to reduce pollution, especially during the rainy season, through biodilution and transport of contaminants out of the system, in a process known as environmental homeostasis (Dyke and Weaver 2013; Elliott and Quintino 2007) (Figs. 16.7
and 16.8). In estuaries with larger river basins and which are more environmentally
variable, such as Caeté and Paranaguá, unless severe, anthropogenic interventions
are more difficult to detected (Barletta et al. 2016; Monteiro et al. 2011). However,
the capacity of Goiana Estuary to withstand modifications is still a hesitation, since
it is located in a short, low discharge, river basin only hundreds of km long and,
therefore, the freshwater influence is small trough most part of the year (Lima et al.
2016).
16.3.3 Implications for the Conservation of Western Atlantic
Estuaries
The connectivity among river basin, coastal zones and coastal waters promoted by
estuarine gradients (ecocline) is currently widely discussed in the scientific literature (Able 2005; Barletta and Blaber 2007; Barletta et al. 2010; Watanabe et al.
2014), and estuaries are well known as important areas for providing biological and
geochemical demands to other environments (Costa and Barletta 2016). These well
established environmental processes need to face a mighty contender, that is intense
societal and economic use and occupation. Estuaries are in coastal zones where
population density is highest, pressures of agricultural and industrial expansion,
improper disposal of wastes and sewages significantly alter natural environments,
water quantities and quality, upsetting local and regional biogeochemical processes,
flora and fauna (Barletta et al. 2010). Therefore, managerial plans should aim at
improve resilience before the modifications experienced by these ecosystems overpass their services capacity (Williams and Crutzen 2013). To support estuarine and
coastal management in an adaptive way, there are robust sampling designs that can
provide consistent ecological and statistically testable data (Kurup et al. 1998;
Worm et al. 2009; Blaber and Barletta 2016; Reis et al. 2016).
16 Estuarine Ecoclines and the Associated Fauna: Ecological Information as the Basis…