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A healthy ocean is vital to our life on Earth. Covering nearly three-quarters of the
surface of the planet, the ocean provides a wide range of resources and services that
support human life, well-being, societies, cultures and economies. As pressure on
the ocean to provide these resources and services increases, its ability to deliver many
of them is compromised.
OUR OCEAN – A BACKDROP
Many human activities that impact ocean health and are
directly relevant to marine vertebrates, and potentially to the
carbon services they provide. Amongst others, these activities
include:
Climate change and ocean acidification –
Impacts are estimated
to cause potential disruption of 60% of the ocean’s present
marine biodiversity by 2050, through local or global extinctions
and changes in the pattern of species’ distributions (Cheung
et al.
2009). Climate change is driving marine vertebrate
migration away from the tropics and toward the poles, with
implications for food security in coastal and island states in the
tropics (Cheung
et al.
2013, Jones and Cheung, 2014); the impact
of this movement for nutrient cycling are largely unexplored.
Rising levels of atmospheric carbon leads to increased amounts
of dissolved carbon in the oceans; while overall still alkaline,
the additional carbon lowers oceanic pH levels (Hönisch
et al.
2012): current rates of this process, termed ocean acidification,
are unprecedented in geological history (Hönisch
et al.
2012).
Ocean acidification impacts the formation of calcium carbonate
(CaCO3) structures and impacts the larvae and adult stages of
many marine vertebrates (Fabry
et al.
2008) and invertebrates:
the impacts on corals and shellfish are expected to present a
serious challenge for the sustainability and way of life for
coastal and island communities (Wittmann and Pörtner 2013,
Mathis
et al.
2014). Through its effects on phytoplankton, ocean
acidification may also impact the formation of clouds and
weather patterns globally (Six
et al.
2013, Arnold
et al.
2013).