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J.E. Merrill
such as water hyacinth (Eichhornia sp.), and duckweed (Lemma sp.);
emergent aquatic plants, such as reed (Phragmites sp.) or cattail (Typha sp;
Wolverton 1987); or fresh water micro algae such as Chlorella, Spirulina,
Scenedesmus, Euglena, etc. (Abeliovich 1986; Oswald 1988; de la Noiie et al.
1992). Similar considerations with marine plants are rare and the scientific
background is correspondingly less well developed (Ryther et al. 1979;
Ryther 1983; Schramm 1991; Subander et al. 1993). To a large extent, a
seaweed bed can be functionally similar to a wetland with regard to the
beneficial characteristics of nutrient removal and water quality improvement. There is no reason why discussions of "artificial wetlands" should
not encompass artificial marine wetlands composed of macroalgal species
and their associated biota. This may be especially important where it is not
possible nor practical to intercept wastewater streams before they enter the
marine environment (i.e., non-point sources). In such circumstances,
artificial plantings of macroalgae could constitute effective in situ phytodepuration systems.
Much of the emphasis applied to finding solutions to the problems of
excess macro algae growth has been focused on harvest and disposal or
utilization of the algal biomass causing the problem (Briand 1991; Morand.
et al. 1991). In this report I will argue for application of an "agricultural
imperative" to the consideration of macro algal blooms in eutrophicated
marine systems. By this I mean that the essential criterion of a eutrophicated system, enrichment with minerals that are plant nutrients,
should be viewed as a potentially valuable resource. A terrestrial farmer,
when confronted with the rampant growth of weeds or other vegetation,
would probably not ask: "What value can I get from these weeds?", but
rather: "What valuable crop could I plant here to take advantage of the
obviously fertile conditions?" If such an approach can be adopted, with
significant development of macro algal seafarms in affected areas, water
quality can be expected to improve through the harvest of useful biomass,
and this at potentially no cost to governments. This would mean a great
benefit compared to the costs (for harvest and disposal) or losses (from
reduced tourism and fisheries revenues) currently incurred from some of
the most severe examples of marine macroalgal blooms.
4.2 The "Green Tide" Phenomenon
A frequent effect of eutrophication in coastal marine ecosystems is the
proliferous growth of macroalgae. Such a response to nutrient enrichment
J.E. Merrill
such as water hyacinth (Eichhornia sp.), and duckweed (Lemma sp.);
emergent aquatic plants, such as reed (Phragmites sp.) or cattail (Typha sp;
Wolverton 1987); or fresh water micro algae such as Chlorella, Spirulina,
Scenedesmus, Euglena, etc. (Abeliovich 1986; Oswald 1988; de la Noiie et al.
1992). Similar considerations with marine plants are rare and the scientific
background is correspondingly less well developed (Ryther et al. 1979;
Ryther 1983; Schramm 1991; Subander et al. 1993). To a large extent, a
seaweed bed can be functionally similar to a wetland with regard to the
beneficial characteristics of nutrient removal and water quality improvement. There is no reason why discussions of "artificial wetlands" should
not encompass artificial marine wetlands composed of macroalgal species
and their associated biota. This may be especially important where it is not
possible nor practical to intercept wastewater streams before they enter the
marine environment (i.e., non-point sources). In such circumstances,
artificial plantings of macroalgae could constitute effective in situ phytodepuration systems.
Much of the emphasis applied to finding solutions to the problems of
excess macro algae growth has been focused on harvest and disposal or
utilization of the algal biomass causing the problem (Briand 1991; Morand.
et al. 1991). In this report I will argue for application of an "agricultural
imperative" to the consideration of macro algal blooms in eutrophicated
marine systems. By this I mean that the essential criterion of a eutrophicated system, enrichment with minerals that are plant nutrients,
should be viewed as a potentially valuable resource. A terrestrial farmer,
when confronted with the rampant growth of weeds or other vegetation,
would probably not ask: "What value can I get from these weeds?", but
rather: "What valuable crop could I plant here to take advantage of the
obviously fertile conditions?" If such an approach can be adopted, with
significant development of macro algal seafarms in affected areas, water
quality can be expected to improve through the harvest of useful biomass,
and this at potentially no cost to governments. This would mean a great
benefit compared to the costs (for harvest and disposal) or losses (from
reduced tourism and fisheries revenues) currently incurred from some of
the most severe examples of marine macroalgal blooms.
4.2 The "Green Tide" Phenomenon
A frequent effect of eutrophication in coastal marine ecosystems is the
proliferous growth of macroalgae. Such a response to nutrient enrichment