4.6 Environmental Implications
79
plants, and they synthesize their food from nutrients extracted from the aquatic system they grow in. These could be the waste produced by other species, thereby
cleaning up the environment which helps to promote and sustain the growth of other
species. Such that farming of seaweeds alongside other fed species of aquatic animals
within the same culture is encouraged in order to benefit from the synergy between
extractive and fed species for optimal use of resources. This has become common
place as the farming of extractive species is estimated at 49.5% as of 2016 (FAO
2018).
Another advantage of wild seaweed as a source of alginate is that it requires
even much less intensive care such as watering, fertilizer application and weeding as
required by land crops. On the other hand, the cost of sending vessels out to sea and
into rocky coasts, the machinery and manpower required for harvesting contribute
to the cost of the raw material which varies around 50–100 USD per MT depending
on the quality and source (Konda et al. 2015).
Although seaweed grows naturally in the wild, meeting the demand for future
commercial alginate production cannot be sustained by the natural stocks alone.
This means new technologies need to be developed for more profitable cultivation of
alginocytes on commercial scale. There are also issues concerning the overexploitation of natural seaweed resource as the demand for seaweed continues to rise. Recent
concerns of overexploitation, environmentally harvesting methods and diminishing
seaweed beds have lead to restriction of harvesting of some species of seaweeds in
countries such as Canada and Portugal (Monagail et al. 2017).
The seaweeds in nature play a significant role in sustaining the aquatic flora and
fauna. They help remove waste products of aquatic animals preventing toxic levels
which could be harmful to the animals and other organisms. They also provide
shade from light to aquatic organisms which thrive better under low light, and they
serve as habitat and refuge to some aquatic organisms, offering protection from
predators. Seaweeds also have the impact of dampening tidal waves by absorbing
the wave energy, thereby preventing or reducing coastline erosion (Monagail et al.
2017). Seaweed harvesting has also been shown to significantly alter biodiversity and
population of some species in areas such that commercial-scale harvesting of wild
seaweed for alginate production pose some significant impact on aquatic ecosystem.
Global climate change has been shown to have affected seaweed species distribution. The reported 0.6 °C increase in temperature has had notable impact on species
distributions in areas such as Spain and Portugal, while extreme weather conditions
like earthquakes, tsunamis and el nino have resulted in total eradication of seaweed
beds in areas such as Chile (Castilla et al. 2010).
Brown algae are typically harvested by cutting the upper part where much of
the useful carbohydrates are found, leaving behind the lower part which allows the
regrowth of the plant within a year or two. The rate of regeneration after harvest
depends on factors such as the efficiency of the harvest method, species, environment
and others. The harvest could be done by hand, using rakes with boats, diving, use of
cutters or mechanical means. Mechanical harvesting has been discontinued in some
areas due to adverse effect on the seaweed population and environment (Monagail
et al. 2017).
79
plants, and they synthesize their food from nutrients extracted from the aquatic system they grow in. These could be the waste produced by other species, thereby
cleaning up the environment which helps to promote and sustain the growth of other
species. Such that farming of seaweeds alongside other fed species of aquatic animals
within the same culture is encouraged in order to benefit from the synergy between
extractive and fed species for optimal use of resources. This has become common
place as the farming of extractive species is estimated at 49.5% as of 2016 (FAO
2018).
Another advantage of wild seaweed as a source of alginate is that it requires
even much less intensive care such as watering, fertilizer application and weeding as
required by land crops. On the other hand, the cost of sending vessels out to sea and
into rocky coasts, the machinery and manpower required for harvesting contribute
to the cost of the raw material which varies around 50–100 USD per MT depending
on the quality and source (Konda et al. 2015).
Although seaweed grows naturally in the wild, meeting the demand for future
commercial alginate production cannot be sustained by the natural stocks alone.
This means new technologies need to be developed for more profitable cultivation of
alginocytes on commercial scale. There are also issues concerning the overexploitation of natural seaweed resource as the demand for seaweed continues to rise. Recent
concerns of overexploitation, environmentally harvesting methods and diminishing
seaweed beds have lead to restriction of harvesting of some species of seaweeds in
countries such as Canada and Portugal (Monagail et al. 2017).
The seaweeds in nature play a significant role in sustaining the aquatic flora and
fauna. They help remove waste products of aquatic animals preventing toxic levels
which could be harmful to the animals and other organisms. They also provide
shade from light to aquatic organisms which thrive better under low light, and they
serve as habitat and refuge to some aquatic organisms, offering protection from
predators. Seaweeds also have the impact of dampening tidal waves by absorbing
the wave energy, thereby preventing or reducing coastline erosion (Monagail et al.
2017). Seaweed harvesting has also been shown to significantly alter biodiversity and
population of some species in areas such that commercial-scale harvesting of wild
seaweed for alginate production pose some significant impact on aquatic ecosystem.
Global climate change has been shown to have affected seaweed species distribution. The reported 0.6 °C increase in temperature has had notable impact on species
distributions in areas such as Spain and Portugal, while extreme weather conditions
like earthquakes, tsunamis and el nino have resulted in total eradication of seaweed
beds in areas such as Chile (Castilla et al. 2010).
Brown algae are typically harvested by cutting the upper part where much of
the useful carbohydrates are found, leaving behind the lower part which allows the
regrowth of the plant within a year or two. The rate of regeneration after harvest
depends on factors such as the efficiency of the harvest method, species, environment
and others. The harvest could be done by hand, using rakes with boats, diving, use of
cutters or mechanical means. Mechanical harvesting has been discontinued in some
areas due to adverse effect on the seaweed population and environment (Monagail
et al. 2017).