Environmental Engineering Reference
In-Depth Information
almost certainly accelerate over the next several decades in the absence of
immediate and dramatic efforts toward climate mitigation (IPCC 2007c).
Direct effects of changes in ocean temperature and chemistry may
alter the physiological functioning, behavior, and demographic traits (e.g.,
productivity) of organisms, leading to shifts in the size structure, spatial
range, and seasonal abundance of populations. These shifts, in turn, lead
to altered species interactions and trophic pathways as change cascades
from primary producers to upper-trophic-level fi sh, seabirds, and marine
mammals, with climate signals thereby propagating through ecosystems
in both bottom-up and top-down directions. Changes in community
structure and ecosystem function may result from disruptions in biological
interactions (Doney et al. 2012).
Considering these comments it is important to use models of evaluation
which allow to understand and predict the effects of climate variability on
marine food webs and marine productivity which are of great importance.
This is especially true with respect to potential consequences of climate
change on commercially important fi sheries. The use of hydrographic models
coupled to
Nutrient-Phytoplankton-Zooplankton-Detritus
(NPZD) ones to
describe and predict future marine ecosystem dynamics has demonstrated
to be a useful approach that is becoming increasingly widespread (Gibson
and Spitz 2011). This kind of model includes the processes linking the
different components of the water column, which determine both the
functioning and stability of the system: nutrients and phytoplankton +
microzooplankton + mesozooplankton + jellyfi sh + detritus. In addition,
particular “submodel conditions” (e.g., benthic biogeochemical submodel,
ice submodel, etc.) can be input on the described biological scenario. Finally,
this module is fully coupled with a strong physical model (like ROMS:
Regional Ocean Modelling
System) which includes the main processes of the
water column and atmosphere (e.g., currents, physical-chemical properties
of seawater, radiation, air pressure and temperature, etc.). This kind of
numeric tool allows to simulate the marine environment functioning on
a real data basis, as well as to modify scenarios (e.g., climate changes) to
evaluate corresponding consequences on the biological system (Perry 2010,
Jørgensen et al. 2012).
Which are the main parameters to be considered within the
evaluation?
The most useful parameters within the marine environment have been
mentioned in the previous paragraphs, and their corresponding signifi cance
has been highlighted. Even though, several of them deserve to be clearly
pointed out as the principal triggers of new processes due to changing