Coastal Marine Environment Sustainability - Sustainable Practices in Geoenvironmental Engineering - page 302

FIGURE 8.22
Geotextile tube used for protection and creation of a coast.
8.9 Concluding Remarks
The health of coastal marine environments is vital to the productivity of the marine aquatic
resources in the ecosystems within this environment. The oceans and the coastal marine
environments are signiicant resource bases and are essential components of the life-support
system for the human population. The two groups of events that pose signiicant threats to
the health of this environment are distinguished on the basis of natural and man-made . In
the irst instance, the natural events include phenomena such as coastal erosion resulting
from aggressive current, waves, and tidal action. Man-made events result in fouling of the
coastal marine environment and of the seas through discharge of wastes from ocean ves-
sels and from land-based industries and activities. It has been argued that coastal erosion
is also a victim of man-made events, according to the thesis that man-generated variations in
sea level contribute to the aggressive actions of the currents, waves, and tidal actions. The
thrust of this thesis is that global warming is in part responsible for the variations in sea
level not only through ice melting, but also through changes in the seabed levels. Although
a discussion on global warming is not within the purview of this topic, it is nevertheless
important to point out that the many facets of geoenvironmental sustainability are affected
by such an event. Some of these issues have been discussed in Section 1.5 in Chapter 1.
Fouling of the coastal marine environment and of the seawater affects both seawater
and sediments. Contaminants are accumulated in the sediments, whereas others are put
into circulation through the food chain and bioconcentration—ultimately posing health
threats to the human population. Two basic problems exist in respect to fouling of the
coastal marine environment and the seawater: eutrophication and concentration of toxic
and hazardous substances. Figure 8.23 gives an illustration of a simple strategy for reha-
bilitation of the coastal marine environment. Hazardous substances and nutrients have
been discharged into the coastal marine environment for many decades. These have to be
collected and removed. A balance in the amount of nutrients removed is needed. On the