by
Thierry Chopin, Professor of Marine Biology, University of New Brunswick
Seaweed cultivation is well established in Asia and needs little explanation or justification.
In the western world, a renewed interest in seaweed mari-culture has been triggered by their cultivation in integrated multi-trophic aquaculture (IMTA) systems, the emerging understanding of the ecosystem services they provide, and, the development of novel uses and applications.
Seaweeds are excellent nutrient scrubbers
An often forgotten function of seaweeds is that they are excellent nutrient scrubbers (especially of dissolved nitrogen, phosphorus and carbon). We should take advantage of the benefits of nutrients, which, in moderation (i.e. within the assimilative capacity of the ecosystem) are not waste or by-products, but co-products and food.
It is all about recycling, which we have no problem with on land (in your house, office, hotel room, garden, farm, etc.), but for which we experience a mental block when translated to the aquatic and marine environments. We should allocate a value to recapturing feed and energy, otherwise lost, and their conversion into other commercial crops.
Much has been said about carbon sequestration and the development of carbon trading taxes. In coastal environments, mechanisms for the recovery of nitrogen and phosphorus should also be highlighted and accounted for in the form of nutrient trading credits (NTCs, a much more positive approach than taxing).
If the composition of seaweeds can be averaged at around 0.35 percent nitrogen (N), 0.04 percent phosphorus (P) and 3percent carbon (C), and the NTCs valued at US$10-30/kg, US$4/kg and US$25/tonne for N, P and C, respectively, the ecosystem services for nutrient bio-mitigation provided by worldwide seaweed aquaculture (30.1 million tonnes) can be valued at between US$1.124 billion and US$3.231 billion, i.e. as much as 27.6 percent of their present commercial value (US$11.7 billion).
The value of this important service to the environment and, consequently, society has, however, never been accounted for in any budget sheets or business plans of seaweed farms and companies, as seaweeds are being valued only for their biomass and food trading values.
The above calculations are based on costs of recovering nitrogen and phosphorus in wastewater treatment facilities and values often cited for carbon tax schemes. It is interesting to note that the value for carbon is per tonne, whereas those for nitrogen and phosphorus are per kilogram. Nobody seems to have picked up on that when looking at the sequestration of elements other than C. There is more money to be made with NTC (between US$1,124 and 3.231 billion for N and US$48.16 million for P) than with CTC (only US$22.58 million for C).
Moreover, having organisms able to accumulate P is becoming increasingly attractive when considering that, in the not too distant future, the next P peak will not be that of petroleum, but that of phosphorus.
The recognition and implementation of NTCs would give a fair price to seaweeds and other extractive aquaculture species. They could be used as financial incentive tools to encourage mono-aquaculturists to contemplate IMTA as a viable aquanomic option to their current practices.
Read the full article in the International Aquafeed magazine online, HERE.
Seaweed cultivation is well established in Asia and needs little explanation or justification.
In the western world, a renewed interest in seaweed mari-culture has been triggered by their cultivation in integrated multi-trophic aquaculture (IMTA) systems, the emerging understanding of the ecosystem services they provide, and, the development of novel uses and applications.
Seaweeds are excellent nutrient scrubbers
An often forgotten function of seaweeds is that they are excellent nutrient scrubbers (especially of dissolved nitrogen, phosphorus and carbon). We should take advantage of the benefits of nutrients, which, in moderation (i.e. within the assimilative capacity of the ecosystem) are not waste or by-products, but co-products and food.
It is all about recycling, which we have no problem with on land (in your house, office, hotel room, garden, farm, etc.), but for which we experience a mental block when translated to the aquatic and marine environments. We should allocate a value to recapturing feed and energy, otherwise lost, and their conversion into other commercial crops.
Much has been said about carbon sequestration and the development of carbon trading taxes. In coastal environments, mechanisms for the recovery of nitrogen and phosphorus should also be highlighted and accounted for in the form of nutrient trading credits (NTCs, a much more positive approach than taxing).
If the composition of seaweeds can be averaged at around 0.35 percent nitrogen (N), 0.04 percent phosphorus (P) and 3percent carbon (C), and the NTCs valued at US$10-30/kg, US$4/kg and US$25/tonne for N, P and C, respectively, the ecosystem services for nutrient bio-mitigation provided by worldwide seaweed aquaculture (30.1 million tonnes) can be valued at between US$1.124 billion and US$3.231 billion, i.e. as much as 27.6 percent of their present commercial value (US$11.7 billion).
The value of this important service to the environment and, consequently, society has, however, never been accounted for in any budget sheets or business plans of seaweed farms and companies, as seaweeds are being valued only for their biomass and food trading values.
The above calculations are based on costs of recovering nitrogen and phosphorus in wastewater treatment facilities and values often cited for carbon tax schemes. It is interesting to note that the value for carbon is per tonne, whereas those for nitrogen and phosphorus are per kilogram. Nobody seems to have picked up on that when looking at the sequestration of elements other than C. There is more money to be made with NTC (between US$1,124 and 3.231 billion for N and US$48.16 million for P) than with CTC (only US$22.58 million for C).
Moreover, having organisms able to accumulate P is becoming increasingly attractive when considering that, in the not too distant future, the next P peak will not be that of petroleum, but that of phosphorus.
The recognition and implementation of NTCs would give a fair price to seaweeds and other extractive aquaculture species. They could be used as financial incentive tools to encourage mono-aquaculturists to contemplate IMTA as a viable aquanomic option to their current practices.
Read the full article in the International Aquafeed magazine online, HERE.
The Aquaculturists
This blog is maintained by The Aquaculturists staff and is supported by the
magazine International Aquafeed which is published by Perendale Publishers Ltd
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