178
8 Ulvans
and chemicals involved in the whole process from harvesting of the raw material to
the final product leaving the production factory gate.
8.6.1 Cultivation and Harvest of Green Algae
In the wild aquatic ecosystem, green algae play a significant role in carbon and
nitrogen fixation as well as maintaining oxygen levels. These are essential to other
life forms in the aquatic ecosystem. Harvesting of green algae from the wild should
therefore give careful consideration to the impact of disrupting the existing balance
within the environment where green algae play a key role. The system of harvesting
from the wild should therefore implement a method where the total population of
algae at any given time is maintained by balancing the rate of harvesting and the rate
of replenishing.
Another issue with cultivation of green algae for commercial purpose is the danger
of introducing exotic strains into the wild, thereby propagating algae blooms or
artificially creating an environment which favors unnatural growth rate of green
algae. This is a likely outcome in algae cultivation in aquaculture systems operating
within the open sea (mariculture). Recent investigations into the cause of the green
tides experienced along the Jiangsu coast of China revealed that the U. prolifera
which is the predominant species causing the green tides in the region is genetically
similar to that growing in the Porphyra mariculture located along the same Jiangsu
coast (Zhang et al. 2019).
In China, for example, the economic loss from the green tide algae bloom has
been estimated at over 183 million USD (1.3 billion RMB) (Zhang et al. 2019). This
loss comes from the loss of income resulting from decline in aquatic organism as a
result of hypoxia (oxygen depletion in the water), loss of income from recreational
and tourist activities on the shoreline as a result of loss of aesthetics, foul smell and
health risk associated with the green tides.
The cultivation of green algae for production of ulvans must therefore be carefully
considered to prevent the risk of propagating green tides which result in serious
adverse environmental impact.
8.6.2 Water Consumption
The extraction process is an aqueous one such that water serves as the solvent for
extraction. Water is also used in the washing of the raw material during cleaning
and pretreatment. Following extraction and separation of the gel, the water which
contains impurities then needs to be treated before release into the environment.
Depending on the level of treatment, this inevitably involves release with a level of
contamination into the environment.
8 Ulvans
and chemicals involved in the whole process from harvesting of the raw material to
the final product leaving the production factory gate.
8.6.1 Cultivation and Harvest of Green Algae
In the wild aquatic ecosystem, green algae play a significant role in carbon and
nitrogen fixation as well as maintaining oxygen levels. These are essential to other
life forms in the aquatic ecosystem. Harvesting of green algae from the wild should
therefore give careful consideration to the impact of disrupting the existing balance
within the environment where green algae play a key role. The system of harvesting
from the wild should therefore implement a method where the total population of
algae at any given time is maintained by balancing the rate of harvesting and the rate
of replenishing.
Another issue with cultivation of green algae for commercial purpose is the danger
of introducing exotic strains into the wild, thereby propagating algae blooms or
artificially creating an environment which favors unnatural growth rate of green
algae. This is a likely outcome in algae cultivation in aquaculture systems operating
within the open sea (mariculture). Recent investigations into the cause of the green
tides experienced along the Jiangsu coast of China revealed that the U. prolifera
which is the predominant species causing the green tides in the region is genetically
similar to that growing in the Porphyra mariculture located along the same Jiangsu
coast (Zhang et al. 2019).
In China, for example, the economic loss from the green tide algae bloom has
been estimated at over 183 million USD (1.3 billion RMB) (Zhang et al. 2019). This
loss comes from the loss of income resulting from decline in aquatic organism as a
result of hypoxia (oxygen depletion in the water), loss of income from recreational
and tourist activities on the shoreline as a result of loss of aesthetics, foul smell and
health risk associated with the green tides.
The cultivation of green algae for production of ulvans must therefore be carefully
considered to prevent the risk of propagating green tides which result in serious
adverse environmental impact.
8.6.2 Water Consumption
The extraction process is an aqueous one such that water serves as the solvent for
extraction. Water is also used in the washing of the raw material during cleaning
and pretreatment. Following extraction and separation of the gel, the water which
contains impurities then needs to be treated before release into the environment.
Depending on the level of treatment, this inevitably involves release with a level of
contamination into the environment.