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J.E. Merrill
or eliminated. If we adopt the agricultural imperative our focus changes
from that of "what can we do with the seaweed that is here?" to "what
valuable seaweed crop can we produce in these fertile waters?" Although the
technologies for macroalgal sea farming are admittedly less well developed
than are those for terrestrial plant crops, the systems that currently exist
provide us with numerous options for either direct application or as starting
points for development of new technologies for unique circumstances.
In the context of this report, combatting eutrophication and reducing
macro algal blooms are primary objectives. Nutrient uptake will place the
cultivated species in direct nutrient competition with the naturallyoccurring bloom-forming species. The nutrients absorbed by the cultivated algae
are removed from the ecosystem through harvest. When the method chosen
for cultivation involves off-bottom suspension of nets or ropes as the
cultivation substrate there will be an additional advantage in the competition for sunlight. The overall biomass of problem-causing species should
decrease by these actions. In those situations where damaging phenomena
occur only when the green tide biomass exceeds certain threshold levels (as
in the case of hypoxia), the partial reduction in biomass resulting from
competition with cultivated macro algae may significantly alleviate the
critical phenomena, even though a complete elimination of the causative
species is not achieved. Furthermore, in the absence of any harvesting of
biomass, the nutrients that contributed to the bloom are typically recycled
back into the water column or the sediments when the algae die and decay.
Such cycling of nutrients is a major contributor to successive blooms. Thus,
any harvest of algal biomass will be beneficial with respect to decreasing the
possibility of future blooms since such harvests will reduce that portion of
the nutrient budget contributed by cycling.
A key element in any consideration of possible pollution abatement
plans will be the overall costs associated with any specific action. I have
summarized some of the more dramatic examples of green tides and the
costly efforts applied to their abatement. Sea farming of macroalgae offers
the possibility for water quality improvement to be accomplished at a net
profit; in fact, with establishment of a permanent new industry in the
affected communities. It is highly likely that government financial assistance will be required, especially during the planning and evaluation stage of
any new endeavor, but these expenses should be a one-time investment,
and more than justified in comparison to the recurrent costs of harvesting
and disposal of low value green tide biomass.
J.E. Merrill
or eliminated. If we adopt the agricultural imperative our focus changes
from that of "what can we do with the seaweed that is here?" to "what
valuable seaweed crop can we produce in these fertile waters?" Although the
technologies for macroalgal sea farming are admittedly less well developed
than are those for terrestrial plant crops, the systems that currently exist
provide us with numerous options for either direct application or as starting
points for development of new technologies for unique circumstances.
In the context of this report, combatting eutrophication and reducing
macro algal blooms are primary objectives. Nutrient uptake will place the
cultivated species in direct nutrient competition with the naturallyoccurring bloom-forming species. The nutrients absorbed by the cultivated algae
are removed from the ecosystem through harvest. When the method chosen
for cultivation involves off-bottom suspension of nets or ropes as the
cultivation substrate there will be an additional advantage in the competition for sunlight. The overall biomass of problem-causing species should
decrease by these actions. In those situations where damaging phenomena
occur only when the green tide biomass exceeds certain threshold levels (as
in the case of hypoxia), the partial reduction in biomass resulting from
competition with cultivated macro algae may significantly alleviate the
critical phenomena, even though a complete elimination of the causative
species is not achieved. Furthermore, in the absence of any harvesting of
biomass, the nutrients that contributed to the bloom are typically recycled
back into the water column or the sediments when the algae die and decay.
Such cycling of nutrients is a major contributor to successive blooms. Thus,
any harvest of algal biomass will be beneficial with respect to decreasing the
possibility of future blooms since such harvests will reduce that portion of
the nutrient budget contributed by cycling.
A key element in any consideration of possible pollution abatement
plans will be the overall costs associated with any specific action. I have
summarized some of the more dramatic examples of green tides and the
costly efforts applied to their abatement. Sea farming of macroalgae offers
the possibility for water quality improvement to be accomplished at a net
profit; in fact, with establishment of a permanent new industry in the
affected communities. It is highly likely that government financial assistance will be required, especially during the planning and evaluation stage of
any new endeavor, but these expenses should be a one-time investment,
and more than justified in comparison to the recurrent costs of harvesting
and disposal of low value green tide biomass.