Viewpoint pubs.acs.org/est
Geo-Engineering in LakesA Call for Consensus Bryan M. Spears,*,† Bernard Dudley,† Kasper Reitzel,‡ and Emil Rydin§ †
Centre for Ecology and Hydrology in Edinburgh, Penicuik, Midlothian, Scotland, UK EH26 0QB Institute of Biology, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark § Erken Laboratory, Department of Ecology and Genetics, Uppsala University, Norrtälje, Sweden ecosystems is rapidly increasing.2 In the EU around 36% (i.e., 31,819 km2 total lake surface area; http://www.eea.europa.eu/ data-and-maps/data/wise_wfd) of all reported WFD lakes fail water quality targets based on ecological condition. The main driver of ecological deterioration in lakes within urban and rural catchments is P pollution, although it is unlikely that P will be the only pressure requiring management in most lakes. Given that current cost estimates of treating lakes with popular geoengineering products range between €0.3 million and €0.8 million per km2 lake surface area (i.e., for aluminum and lanthanum based products, respectively), it is important that the application of this technique be based on sound scientific understanding. Failure to achieve these water quality targets can attract significant financial penalties for water authorities and regulators. Of increasing concern is the lack of tested theory and empirical data upon which decisions of field-scale geoengineering in lakes can be based. This is due mainly to the rarity of long-term ecosystem scale experiments that are needed to produce the relevant data.3 For most of the waterbody scale trials conducted to date, the norm is that geo-engineering was selected by water managers for application and researchers find s climate change researchers hotly debate the values and themselves trying to interpret the effects of the treatment based risks associated with atmospheric geo-engineering, 1 on a too-short pre- and post-treatment monitoring program. aquatic ecologists are all too aware of a stark contrast between Such investigations do not capture long-term impacts on biota. the two camps. Unlike proposals for atmospheric manipuIn addition, data from ecosystem experiments that have lations, geo-engineering in lakes and reservoirs using adequate design are often confined to the gray literature and phosphorus(P)-removing materials has been implemented at should be made available, and reports of failed applications are a global scale as a eutrophication management tool for decades extremely rare. The ability of researchers to publish their 2 (Figure 1), in the absence of scientific consensus on its use. findings is limited by the time taken for lakes to respond The technique, known as “P-capping”, can be used to control following perturbation and by the speed of the peer review legacy P stores in bed sediments that have built up over decades process; single year observations can rarely be used to infer the of anthropogenic pollution. If left untreated, these legacy P longer term effects of such techniques. And so we find ourselves stores can prolong water quality improvements for decades relying heavily on results from laboratory based experiments 3 following catchment management. As well as accelerating that may not reflect ecosystem scale responses.3 recovery of nutrient-impacted waterbodies, geo-engineering is The understandable disconnects between the needs of often considered in isolation of catchment nutrient manageproduct suppliers, water managers, researchers, regulators, ment measures due to its low relative cost and ability to and policy makers can be bridged through coherent and produce rapid short term improvements in water quality.4,5 transparent analysis of existing and future data. Disconnects are However, many knowledge gaps exist with respect to the manifest within a lack of consensus on how to assess the need technique’s efficacy, and the scientific evidence is not yet for geo-engineering at the site-specific scale, the potential available with which wide scale application can be supported. negative impacts of geo-engineering on lake ecology and We argue that a comprehensive analysis of data and increased biogeochemical cycling, the expected effective period of coherence across future geo-engineering research programs is treatment, the physical and chemical conditions of receiving necessary to deliver advances in theoretical and practical waterbodies that may retard operational performance of knowledge needed to improve the efficacy of the approach. products, the methods of estimating effective dose and With the recent introduction of water quality targets and therefore cost of treatment, and appropriate application deadlines for standing waters, e.g. as part of the EU Water Framework Directive (WFD) or the Clean Water Act in the United States, the scale of the geo-engineering debate in aquatic Published: April 24, 2013 ‡
A
© 2013 American Chemical Society
3953
dx.doi.org/10.1021/es401363w | Environ. Sci. Technol. 2013, 47, 3953−3954
Environmental Science & Technology
Viewpoint
Guidance should be prepared to ensure that monitoring activities are conducted consistently and that future data are comparable. Finally, a technical advisory group should be established within this network with the task of improving communication across environmental policy, research, regulation, and industrial sectors. We believe that by increasing coherence across the communities in the field the debate on geo-engineering in lakes can be developed to inform similar debates in other research fields. Critical to this will be our ability to document and learn from past successes and failures.
■
AUTHOR INFORMATION
Corresponding Author
*E-mail:
[email protected]. Notes
The authors declare no competing financial interest.
■
REFERENCES
(1) Matthews, H. D.; Turner, S. E. Of mongooses and mitigation: Ecological analogues to geoengineering. Environ. Res. Lett. 2009, 4, 045105. (2) Conley, D. J. Save the Baltic Sea − Geoengineering efforts to bring oxygen to the deep Baltic should be abandoned. Nature 2012, 486, 463−464. (3) Schindler, D. W. The dilemma of controlling cultural eutrophication of lakes. Proc. R. Soc. B: Biol. Sci. 2012, 279, 4322− 4333. (4) Mehner, T.; Diekmann, M.; Gonsiorczyk, T.; Kasprzak, P.; Koschel, R.; Krienitz, L.; Rumpf, M.; Schulz, M.; Wauer, G. Rapid Recovery from Eutrophication of a Stratified Lake by Disruption of Internal Nutrient Load. Ecosystems 2008, 11 (7), 1142−1156. (5) Hickey, C. W.; Gibbs, M. M. Lake sediment phosphorus release managementDecision support and risk assessment framework. N. Z. J. Mar. Freshwater Res. 2009, 43 (3), 819−854.
Figure 1. Application of lanthanum-modified bentonite to a freshwater reservoir, Scotland, UK.
procedures.4,5 In addition, the unintended socioeconomic impacts of such large scale management scenarios should be comprehensively assessed against the ability of communities to pay for them. Undoubtedly, the scale of the problem should attract significant industrial investment, and opportunities for using locally produced and supplied products should be explored further in the context of energy efficiency and cost during production and application. In some cases attention has been given to identifying waste products from industry for use as geo-engineering materials in aquatic ecosystems.5 However, with a rapidly expanding market comes an ever increasing need to test new products proposed for use at the field scale. All parties stand to gain by responding collectively to this need for consensus. Joint national research networks like the Danish CLEAR center (http://www.lake-restoration.net/) should serve as a model for larger international networks, providing the necessary practical guidance to support waterbody management, on the ground. By creating national and multinational research networks it should be possible to support research opportunities that are beyond the scope of single site studies. The advent of open access data publishing should be used as a catalyst for collecting and compiling existing “dormant” data sets. Greater effort should be made to consolidate resources across regulators, water managers, researchers, and industry with financial support being made to ensure collaborative long-term monitoring of treated waterbodies. To achieve this, we call for an International Aquatic Geo-engineering Network to be established. The network should facilitate the registration of treated lakes and provide a universal data compilation and storage facility. 3954
dx.doi.org/10.1021/es401363w | Environ. Sci. Technol. 2013, 47, 3953−3954
