225
In this chapter we compilled peer-reviewed published studies that adopted SIA to
investigate such ecological aspects of marine mammals in the SAO. First we explore
several studies for which this methodology was used to describe trophic and/or
spatial ecology of cetaceans, pinnipeds and sirenians (Table 9.1). Then we show
results of the only application of Ba/Ca ratios to study the spatial ecology of marine
mammals. Finally we conclude our review with some recommendations on future
applications that will help encouraging research groups to take further advantage of
these increasingly available chemical techniques. We also highlighted the importance of long-term sampling effort and scientific collections as source of valuable
material for the use of SIA and trace elements to enhance the knowledge on important aspects regarding the spatial and trophic ecology of marine mammals.
9.2 Stable Isotopes
In this section, we present the main findings of researchers using the stable isotope
technique, refered in the introduction of the chapter (Table 9.1), separated by the
main groups of marine mammals.
9.2.1 Cetaceans
Cetaceans are highly mobile organisms with sometimes large home ranges. These
characteristics together with their complete aquatic habitat, including remote oceanic regions, make the study of their biology and ecology a difficult task. Therefore,
SIA has been largely applied to answer variety of research questions about the ecology of this taxon (see review by Newsome et al. 2010). Several research groups in
Brazil, Uruguay and Argentina are increasingly applying these chemical tracers as
tools for investigating different aspects of the ecology of several cetacean species
from SIA. Figure 9.2 ilustrates, though schematically, the outcome of its application
for describing the spatial ecology of some species inhabiting the region.
The habitat use and trophic level of several dolphin species in a coastal-oceanic
gradient were analyzed by means of SIA in areas ranging from tropical (Bisi et al.
2013; Baptista et al. 2016) to sub-tropical (Botta et al. 2012) and sub-Antarctic
(Riccialdelli et al. 2010). The main aim of these studies was to reveal patterns of
habitat use and trophic positions of a variety of dolphin species within the coastal to
oceanic marine food webs. Stable isotopic values in muscle of bottlenose dolphins
(Tursiops truncatus), rough-toothed dolphins (Steno bredanensis), Guiana dolphins
(Sotalia guianensis) (Bisi et al. 2013; Baptista et al. 2016), franciscanas (Pontoporia
blainvillei) (Baptista et al. 2016), Atlantic spotted dolphin (Stenella frontalis), pantropical spotted dolphin (S. attenuata), spinner dolphin (S. longirostris), Risso’s
dolphin (Grampus griseus), Fraser’s dolphin (Lagenodelphis hosei), common dolphins (Delphinus sp.) and false killer whales (Pseudorca crassidens) (Bisi et al.
9 Using Chemical Elements to the Study of Trophic and Spatial Ecology in Marine…
In this chapter we compilled peer-reviewed published studies that adopted SIA to
investigate such ecological aspects of marine mammals in the SAO. First we explore
several studies for which this methodology was used to describe trophic and/or
spatial ecology of cetaceans, pinnipeds and sirenians (Table 9.1). Then we show
results of the only application of Ba/Ca ratios to study the spatial ecology of marine
mammals. Finally we conclude our review with some recommendations on future
applications that will help encouraging research groups to take further advantage of
these increasingly available chemical techniques. We also highlighted the importance of long-term sampling effort and scientific collections as source of valuable
material for the use of SIA and trace elements to enhance the knowledge on important aspects regarding the spatial and trophic ecology of marine mammals.
9.2 Stable Isotopes
In this section, we present the main findings of researchers using the stable isotope
technique, refered in the introduction of the chapter (Table 9.1), separated by the
main groups of marine mammals.
9.2.1 Cetaceans
Cetaceans are highly mobile organisms with sometimes large home ranges. These
characteristics together with their complete aquatic habitat, including remote oceanic regions, make the study of their biology and ecology a difficult task. Therefore,
SIA has been largely applied to answer variety of research questions about the ecology of this taxon (see review by Newsome et al. 2010). Several research groups in
Brazil, Uruguay and Argentina are increasingly applying these chemical tracers as
tools for investigating different aspects of the ecology of several cetacean species
from SIA. Figure 9.2 ilustrates, though schematically, the outcome of its application
for describing the spatial ecology of some species inhabiting the region.
The habitat use and trophic level of several dolphin species in a coastal-oceanic
gradient were analyzed by means of SIA in areas ranging from tropical (Bisi et al.
2013; Baptista et al. 2016) to sub-tropical (Botta et al. 2012) and sub-Antarctic
(Riccialdelli et al. 2010). The main aim of these studies was to reveal patterns of
habitat use and trophic positions of a variety of dolphin species within the coastal to
oceanic marine food webs. Stable isotopic values in muscle of bottlenose dolphins
(Tursiops truncatus), rough-toothed dolphins (Steno bredanensis), Guiana dolphins
(Sotalia guianensis) (Bisi et al. 2013; Baptista et al. 2016), franciscanas (Pontoporia
blainvillei) (Baptista et al. 2016), Atlantic spotted dolphin (Stenella frontalis), pantropical spotted dolphin (S. attenuata), spinner dolphin (S. longirostris), Risso’s
dolphin (Grampus griseus), Fraser’s dolphin (Lagenodelphis hosei), common dolphins (Delphinus sp.) and false killer whales (Pseudorca crassidens) (Bisi et al.
9 Using Chemical Elements to the Study of Trophic and Spatial Ecology in Marine…