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SeaWeed - Some useful "weeds"

SeaweedAfrica: an Internet database for the sustainable use of seaweed biodiversity in Africa

Humans have found uses for seaweed for more than a thousand years. In parts of Europe, the oldest written records indicate that dulse (Palmaria palmata) has been collected from rocky shores since at least 600AD. Nori (Porphyra sp.) has been a cultivated cash crop for about 300 years in the East. Nori is an essential component of soups and increasingly popular sushi rolls. In Scotland and Ireland, dulse is eaten dried like potato crisps but is also added to many basic dishes. Perhaps the most important product extracted from seaweeds, however, are the hydrocolloids - gelling polysaccharides (chains of simples sugars) that can be likened to gelatine obtained from animals.

Food, cosmetic and pharmaceutical industries use three common types of hydrocolloid extensively when thickening or gelling properties are required: carrageenan and agar from red seaweeds and alginic acid from brown seaweeds. Green seaweeds do not contain any hydrocolloids which are used industrially, though they have other uses.

New and more advanced uses are being developed for these gels and for other seaweed products. Until now, there has been no centralised source or efficient method of keeping up to date with developments in the seaweed industry. SeaweedAfrica is a European Union-funded project to expand AlgaeBase, a global biodiversity database of seaweed information, to include ecological, commercial and technology data from the whole of Africa. SeaweedAfrica brings together the expertise of scientists from Ireland, Sweden, France, Portugal, Kenya, Tanzania, Moçambique, South Africa, Namibia and Brazil. One of the important aims of the collaboration is to establish a database that includes detailed information of the world-wide use (current or potential) of macroalgae.

Following a detailed literature and Internet survey, many current and potential uses of seaweeds have been identified and catalogued. For ease of access, these have been organised into the following categories: i) aesthetics, ii) agriculture, horticulture and agronomy, iii) uses in animal aquaculture, iv) cosmetics, v) environmental health, monitoring and remediation, vi) food, vii) health, thalassotherapy and wellness, viii) industry, ix) pharmaceutical and pharmacology, x) science, technology & biomedicine, xi) miscellaneous uses. The number of uses in each of these categories is shown in the table below.

Categories of seaweed uses in the SeaweedAfrica 'Uses Database' 

It is evident that most people unknowingly utilise seaweed products daily in the form of many convenience foods (processed dairy, meat and fruit products) and domestic commodities (paint, toothpaste, solid air fresheners, cosmetics, etc.). But the cryptic nature of seaweed utilisation contributes to this valuable and renewable resource being generally unappreciated and undervalued by the public.

While the many uses of seaweeds are currently published, many of the records are in specialised journals; the SeaweedAfrica database collates them for the first time. The incredible number of uses that have been documented has surprised even the specialists involved and serves to underline the importance of seaweeds in the world today and the need for concentrated efforts to promote research into the potential uses of these 'weeds'. Of particular interest are the many pharmaceutical applications, in particular due to biologically-active secondary metabolites, and the scientific/biomedical sectors incorporating novel uses and applications of hydrocolloids.

Among the more important potentially useful algae are Aghardhiella subulata (cited as A. tenera) which may be useful in the treatment of the human immunodeficiency virus or HIV, and the edible wakame (Undaria pinnatifida) which some researchers speculate may prevent breast cancer. The fact that the SeaweedAfrica database is directly linked to the main AlgaeBase database will mean that all data will be referenced to current taxonomic and nomenclatural data (the need for this can be clearly seen in the above example of Agardhiella).

Studies on the diversity, physiology, biochemistry and utilisation of potentially useful species will be necessary to harness the full potential of seaweed resources and to do so sustainably. This is particularly true in Africa which can successfully use examples from South East Asia which has a long history of seaweed utilisation. It is envisioned that an industry based on seaweeds has the potential to contribute to sustainable employment opportunities and socio-economic upliftment in emerging economies. African coasts have a generally high biodiversity of seaweeds where opportunities for specialisation of utilisation and development of niche products based on seaweed raw materials from pollution-free environments may be key marketing advantages.

SeaweedAfrica will contribute by gathering relevant information in both European and African contexts and constructing a user-friendly online database for practitioners and decision makers. Accessibility to the information will be ensured via general availability on the Internet and distribution of CD ROM's and information packs (free of charge) where appropriate. The database is currently in a development stage and is not yet available to the general public. Intensive testing begins in November and soon after the database will be available to the general public and other interested parties. The background to the SeaweedAfrica project is available via www.SeaweedAfrica.org. Additional seaweed information can be found at www.AlgaeBase.org.

More information: 

Authors of SeeWeedAfrica are: Smit, AJ (1), Critchley, AT (2), Keats D (3), Nic Donncha, E (4), Cocks, M (5), Molloy, FJ (6), Anderson RJ (7), Bolton JJ1, Guiry, MD (7)

1 Department of Botany, The University of Cape Town, South Africa
2 Degussa Texturant Systems France SAS, Baupte 50500, France
3 Information and Communication Services, University of the Western Cape, South Africa
4 AlgaeBase Centre, Martin Ryan Institute, National University of Ireland, Galway, Ireland
5 International Ocean Institute, Southern Africa, University of the Western Cape, South Africa
6 University of Namibia, Henties Bay Centre, Windhoek, Namibia
7 Marine and Coastal Management, c/o University of Cape Town, Department of Botany, South Africa

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