Metabolomics for biomonitoring: an evaluation of the metabolome as an indicator of aquatic ecosystem health.

Global degradation of aquatic ecosystems has initiated widespread use of biomonitoring to inform management. Current biomonitoring programs typically apply biomarkers (e.g., vitellogenin) and (or) measurements of community composition (e.g., algae or benthic macroinvertebrates) as indicators to assess ecosystem condition. However, independently these indicators may fail to provide either ecologically significant (a limitation of biomarkers) or early warning (a limitation of population and community measures) information to aquatic managers. Environmental metabolomics studies the relationship between an organism's environment and its metabolome (i.e., description of the state of molecules produced or consumed during an organism's metabolic processes, e.g., amino acids). Shifts in the metabolome occur because of stress-driven changes in resource allocation and are often indicative of changes in organism fitness. The metabolome of target species may thus be an effective bioindicator; however, it has not been evaluated for use in aquatic biomonitoring. Our objectives were threefold: introduce and describe metabolomics, evaluate the metabolome as a bioindicator, and provide recommendations for integration of metabolomics into biomonitoring. We conclude that the metabolome meets many bioindicator criteria and the potential to meet the remaining criteria following further research. Specifically, we concluded the metabolome is grounded in sound ecological theory while also having the potential to be a priori predictive and to assess ecological functions. Although the reliability of the metabolome to detect change needs further study, there is growing evidence that the metabolome can detect changes in human impact and discriminate between stressors. We provide an example of this capability with a case study assessment of municipal wastewater. Practically, the metabolome can be readily integrated into existing biomonitoring protocols. However, the ability of agencies to adopt metabolomics-based biomonitoring may be impeded by a lack of understanding of metabolomics within institutions and difficulty of communication with stakeholders. We suggest training or hiring of appropriate personnel and the generation of a common metabolomics language as mechanisms for overcoming this impediment. We conclude that background knowledge for metabolomics-based monitoring is sufficient for agency-based pilot projects aimed at assessing ecological status of aquatic ecosystems. However, continued development may ultimately provide early warning and diagnostic assessments of aquatic impacts. [ABSTRACT FROM AUTHOR]