Aquatic plants: an opportunity feedstock in the age of bioenergy

311 ISSN 1759-7269 10.4155/BFS.10.2 © 2010 Future Science Ltd †Author for correspondence Soil and Water Science Department, University of Florida-IFAS, PO Box 110960, Gainesville, FL 32611-0960, USA Tel.: +1 352 392 8699; Fax: +1 352 392 7008; E-mail: [email protected] Critical problems such as anthropogenic climate change, dwindling oil supplies and rural under development have sparked global interest in harnessing renewable energy sources. While biofuels, such as ethanol, and other forms of biomass-based energy (i.e., bioenergy) are widely regarded as being among the most promising renewableenergy pathways [1,2], there is significant concern that land-use changes implied by large-scale bioenergy production could pose substantial risks to both the natural environment [3–5] and human well-being [6]. Accordingly, there is a growing impetus to identify and develop bioenergy feedstocks that can be harnessed in ways that do not require major land-use intens ification or use of food crops. Much attention, for example, has been given to potential environmental benefits associated with cultivation of perennial grasses for bioenergy production on marginal and/or degraded crop land [7–9]. Other pathways that are being extensively explored for their potential to reduce bioenergy’s land footprint range from increased utilization of residues from existing crop and forestry lands [10,11], to the biotechnological development of algal species that can be cultivated with extremely high areal biomass yield rates [12,13]. However, major challenges and limitations identified for large-scale utilization of perennial grasses [14,15], residual biomass [16–18] and algal culture [19] make it clear that there is no ‘silver bullet’ solution to sustainable bioenergy production likely. Instead, there will have to be many solutions that are designed to take advantage of the specific resources available in different local and regional contexts. This review makes the case that invasive aquatic plant biomass represents an untapped potential source of bioenergy that, while still having major challenges and limitations, is intriguing in the sense that a whole suite of socioenvironmental benefits can be seen to accrue in conjunction with increased utilization. Since invasive aquatic plants produce enormous amounts of biomass and adversely affect natural environments (i.e., areas without direct human impact), sustained removal of this biomass will generally have benefits for the nutrient balance and native ecology of affected aquatic ecosystems. Moreover, beneficial bioenergy utilization of what is essentially a nuisance waste can be seen as Biofuels (2010) 1(2), 311–321 Aquatic plants: an opportunity feedstock in the age of bioenergy