Primary production
In the marine environment the most important organisms for
primary production are phytoplankton; tiny microscopic plants that
are found in the upper layer of the ocean where sunlight reaches.
This accounts for about half of the primary production of the
Earth.
Phytoplankton are the first link in the chain between harvesting
energy from the sun and making it available to animals, such as
zooplankton. Zooplankton are in turn the most important source of
food for fish, which provides approximately one billion people with
their main source of protein.
The size and structure of the plankton community can affect the
balance between production and respiration. This is important for
determining whether there will be a net uptake or release of
CO2, which is referred to as the metabolic balance of
the ecosystem. For example, when an area is dominated by bacteria,
this area may switch from uptake of CO2 to release of
the gas into the ocean and subsequently into the atmosphere.
In order to investigate the metabolic balance of ecosystems on a
global scale it is necessary to use knowledge from very small-scale
processes and extrapolate this to the global scale. This can only
be done by ecosystem modelling and exploring large data sets. By
combining the large data sets from the Atlantic Meridional Transect
(AMT) programme with satellite Earth observation, PML has been able
to produce maps of the metabolic balance of the global ocean for
the first time. Thus, we are now able to identify regions where the
marine ecosystem is a source or a sink for
CO2.
Projects