Preliminary assessment of terrestrial microalgae isolated from lichens as testing species for environmental monitoring: Lichen phycobionts present high sensitivity to environmental micropollutants N. Domínguez-Morueco a,n , H. Moreno a , E. Barreno b , M. Catalá a a Departamento de Biología y Geología, ESCET, Universidad Rey Juan Carlos, C/ Tulipán s/n, 28933 Móstoles, Madrid, Spain b Instituto Cavanilles de Biodiversidad y Biología Evolutiva (ICBIBE), Botánica, Fac.C. Biológicas, Universitat de Valencia, C/ Dr. Moliner 50, 46100 Burjassot, Valencia, Spain article info Article history: Received 9 July 2013 Received in revised form 2 October 2013 Accepted 6 October 2013 Available online 29 October 2013 Keywords: Carbamazepine Diclofenac Lichen phycobionts Microalgae Microbioassays Micropollutants abstract Bioassays constitute a tool for pollution analysis providing a holistic approach and high-quality indica- tion of the toxicity. Microbioassays allow evaluating the toxicity of many samples, implying lower costs and enabling routine monitoring and pollution control. But tests conducted so far are limited to the use of a small number of taxa. Lichens are excellent bioindicators of pollution with great ecological significance. Studies show that the phycobiont is more sensitive to pollutants than the mycobiont. Phycobiont have features such as adaptation to anhydrobiosis and relatively rapid growth in vitro, making them suitable for microbioassays. Our aim is to determine the sensitivity of phycobionts to the pharmaceutical micropollutants carbamazepine and diclofenac as a preliminary step for the develop- ment of a toxicity microbioassay based on phycobionts. Optical dispersion and chlorophyll autofluores- cence were used as endpoints of toxicity on two algal species showing that suspensions present cyclic and taxon specific patterns of aggregation. Trebouxia TR9 suspensions present a very high grade of aggregation while Asterochloris erici cells do not. Both micropollutants alter optical properties of the suspensions of both species. No significant alteration of chlorophyll autofluorescence by carbamazepine is observed. A. erici chlorophyll autofluorescence is extremely sensitive to diclofenac but the effect is not dependent on the drug concentration or on the time of exposure. Differently, TR9 only shows punctual chlorophyll alterations. Fluctuations in optical dispersion may indicate changes in the population structure of the species, including reproductive strategy. A. erici seems more sensitive to micropollutants, is better characterized and is available from commercial collections. & 2013 Elsevier Inc. All rights reserved. 1. Introduction Chemical analysis has historically been the most used method to monitor and evaluate the environmental pollution (Wadhia and Thompson, 2007). These measurements can identify compounds in the environment, but do not give an indication of the bioavail- ability of toxic substances and of the joint effects these compounds may have on the biota (Hendriks et al., 1994, cited in Van der Griten et al., 2010). In this situation, the “bioassay” constitutes a complementary tool of analysis, capable of providing a holistic approach and an indication of the acute toxicity, genotoxicity or chronic effects that the organisms under study undergo (Wadhia and Thompson, 2007; Van der Griten et al., 2010). When conducting bioassays routinely, there may be problems due to the high number of samples, and space and facilities (greenhouses, pools) required, usually reflected in increased eco- nomic costs. This has led to the development of bioassays with miniaturization or micro procedures, known as “microbioassays”. They allow evaluating the toxicity of a high number of samples, implying lower costs and enabling structures for monitoring and pollution control (Wadhia & Thompson, 2007). But tests conducted so far are limited to the use of a small number of taxa, due to either practical or economic criteria, and not by ecological criteria (Catalá et al., 2009). It is therefore necessary to extend the range of action of these studies to more taxa, as usually the most unknown are the most threatened. Microalgae rank among the most frequently used organisms because they provide features such as high sensitivity and a high reproducibility (Shitanda et al., 2009). The organisms referred to as algae are generally a collection of unrelated organisms that possess plastids (Del Campo et al., 2010) Green algae, or Chlorophyta, constitute a huge and extremely diverse phylum of eukaryotic organisms. These eukaryotes must not be confounded with prokar- yotic cyanobacteria, also known as blue-green algae. At present, the Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/ecoenv Ecotoxicology and Environmental Safety 0147-6513/$ - see front matter & 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ecoenv.2013.10.007 n Corresponding author. E-mail address: dm.noelia@gmail.com (N. Domínguez-Morueco). Ecotoxicology and Environmental Safety 99 (2014) 35–44