Environmental Engineering Reference
In-Depth Information
ecological diversity and the variability that present the marine ecosystem
(Moore 2008). Moore (2008) mentioned the use of behavioral ecology of
gray whales (
Eschricthius robustus
) in the eastern North pacifi c and Arctic
to illustrate the importance of ecological scale and considered the use of
marine mammals as sentinels of hotspots in ocean production, changes to
food webs, contaminant levels and disease pathways. We agree with Moore
(2008) that marine mammal's research must be included in local to large
scale ocean studies.
This chapter will address the challenges for marine mammals in a
changing world. The objective is to walk the natural history of marine
mammals and understand how they were affected by climate change-related
reasons, considering anthropogenic causes.
Climate Change and Population Genetic Structure in Marine
Mammals
Climate change and potential impacts on marine mammals
Climate change is considered as one of the main threats to biodiversity at a
global scale. The direct impacts of climate change have been documented on
every continent, in every ocean, and in most taxonomic groups (Parmesan
2006). Predicted impacts of climate change on the marine environment
include, among others, an increase in water temperature, a rise in sea
levels, and a decrease in sea-ice cover (IPCC 2001). These changes in the
marine environment can in turn have direct or indirect potential impacts
on marine mammals. Direct impacts include the effects of reduced sea ice
and rising sea levels on seal haul-out sites, while indirect impacts include
changes in prey availability affecting distribution, abundance and migration
patterns, community structure, susceptibility to disease and contaminants
(Learmonth et al. 2006). Moreover, rapid climate change is likely to impose
strong selection pressures on traits important for fi tness (Gienapp et al
.
2008). One of the potential long term effects of climate change will be
alterations of the genetic structure of wildlife populations (Lynch and
Lande 1993). The knowledge of current genetic structure and the effect of
past climate on patterns of geographical differentiation at the molecular
level may reveal valuable information on the underlying evolutionary
processes and past demographic events (Milá et al. 2000) and would light
up on the future genetic consequences of present climate change (Waltari et
al. 2007). Molecular markers, such as mitochondrial DNA genes and nuclear
microsatellites, have been extensively used in marine mammals in the last
decade for the study of these topics (Trujillo et al. 2004, Weber et al. 2004,
Baker et al. 2005, Hoffman et al. 2006, 2009, Matthee et al. 2006, Fontaine et
al. 2007, Túnez et al. 2007, 2010). In this section, we will review some papers
