Management of Biological Invasions (2018) Volume 9, Issue 2: 85–90 DOI: https://doi.org/10.3391/mbi.2018.9.2.02 © 2018 The Author(s). Journal compilation © 2018 REABIC Open Access 85 Short Communication Spectral characterization of Didymosphenia geminata under laboratory conditions: bases for a monitoring and early warning system in river systems of south central Chile Carlos Esse 1,2, *, Ivo Fustos 5 , Katerina González 4 , Carlos Aguayo 4 , Francisco Encina-Montoya 3 , David Figueroa 4 , Gladys Lara 4 and Celso Navarro 4 1 Instituto de Estudios del Hábitat (IEH), Universidad Autónoma de Chile, Chile 2 Centro de Investigación Multidisciplinario de La Araucanía (CIMA), Universidad Autónoma de Chile, Chile 3 Núcleo de Estudios Ambientales (NEA), Universidad Católica de Temuco-Chile, Chile 4 Laboratorio de Limnología y Recursos Hídricos, Escuela de Ciencias Ambientales, Universidad Católica de Temuco-Chile, Chile 5 Departamento de Ingeniería de Obras Civiles, Universidad de la Frontera, Temuco-Chile, Chile Author e-mails: carlos.esse@uautonoma.cl (CE); ivo.fustos@ufrontera.cl (IF), caguayo@uct.cl (CA), fencina@uct.cl (FEM), dfiguero@uct.cl (DF), kgonzalez@uct.cl (KG), glara@uct.cl (GL) *Corresponding author Received: 3 November 2017 / Accepted: 14 March 2018 / Published online: 6 April 2018 Handling editor: Kirsty Smith Abstract The effects of climate change and the severe anthropization of local river systems have contributed to the alteration of ecological processes, affecting the water quality in these systems and thus generating conditions for the emergence of algal species. In this context, the object of the present study was to evaluate the potential of remote detection techniques to obtain a spectral characterization of D. geminata under controlled laboratory conditions. This would provide the basic information for the design and implementation of a monitoring and early warning system. D. geminata cells obtained from two southern Chilean river systems were cultivated in the laboratory and analysed using hyperspectral techniques to construct their spectral signatures. The results showed the feasibility of distinguishing between the presence and absence of D. geminata when it occurs in association with other diatom present in the environmental. The results could be the first step towards the design and implementation of a monitoring and early warning system to facilitate existing inspection activities. Key words: diatom, invasive algae, hyperspectral analysis, spectrometer, remote sensing Introduction Didymosphenia geminata (Lyngbye) M. Schmidt is a benthic freshwater diatom originally from the northern hemisphere (Reid et al. 2012; Jaramillo et al. 2015). This diatom is capable under certain con- ditions of aggressive invasion of oligotrophic river systems (Whitton et al. 2009; Spaulding et al. 2010; Jaramillo et al. 2015). The river invasion capability of this species translates into rapid proliferation and the formation of very large mucilaginous colonies, constituting a threat to the conservation of fresh- water ecosystems worldwide (Spaulding and Elwell 2007). In the southern hemisphere it was detected in New Zealand in 2004 (Kilroy et al. 2009; Jaramillo et al. 2015) and to date it has colonised high latitudes, for example river systems in the Patagonia region of southern Chile and Argentina (Reid et al. 2012; Reid and Torres 2014; Jaramillo et al. 2015). In Chile, D. geminata—commonly known as Didymo—was first detected in the 1960s in the Aysén and Magallanes Regions, specifically Cisnes River and Sarmiento Lake (Asprey et al. 1964). In 2010 it was detected in the Futaleufú River and since then it has spread into numerous rivers in the south central part of the country (Segura 2011). This situation has caused uncertainty among the population as to its potential effects on human health and on the various ecosystem services associated with river basins (Reid and Torres 2014). The most sensitive goods and services include tourism, water sports, sport fishing and the aquaculture industry. In view of this situation,