Short communication Storage effects on the community level physiological profiles of Mediterranean forest soils M. Goberna a, * , H. Insam b , J.A. Pascual c , J. Sa ´nchez a a Centro de Investigaciones sobre Desertificacio ´n, Generalitat Valenciana, CSIC, Universitat de Valencia, Camı ´ de la Marjal, s/n, Albal 46470, Valencia, Spain b Institut fu ¨r Mikrobiologie, Technikerstr.25 A-6020, Innsbruck, Austria c Centro de Edafologı ´a y Biologı ´a Aplicada del Segura (CEBAS-CSIC), P.O. Box 4195, Murcia 30080, Spain Received 13 November 2003; received in revised form 19 May 2004; accepted 2 June 2004 Abstract Community level physiological profiles (CLPPs) have been implemented in many European soil monitoring programmes as a rapid tool for the assessment of the functional properties of soil microbial communities. However, this technique has not been harmonized among different laboratories. In this experiment, the changes of the CLPPs after storage of three Mediterranean forest soils were characterised for two sampling depths. The methods to store the samples were cooling, freezing and room temperature storage. Data presented in this study provide evidence that substantial changes can occur to the soil microbial community functions, regardless of the kind of storage. Changes in functional diversity and substrate evenness depended on the profile and sampling depth. The rate of consumption of the groups of substrates, however, shifted towards an enhanced utilisation of carboxylic acids, phenols and/or amines after 1 month storage at 4 8C, regardless of the profile or sampling depth. This was attributed to the physical disruption of soil aggregates and exposure of relatively recalcitrant occluded organic matter. These effects levelled out during 1-year storage. The great sensitivity of CLPPs to storage treatment suggests to take care for immediate analysis after sampling. In case fresh samples are not available, freezing is recommended as a convenient alternative; in that case, however, the kinetic approach is required for data analysis. q 2005 Elsevier Ltd. All rights reserved. Keywords: Community level physiological profiles; Storage effects; Mediterranean forest soils Community level physiological profiles (CLPPs), also known as sole-carbon-source utilization tests, have gained widespread use as a tool to discriminate among soils with different uses and impacts of management (Yan et al., 2000; Yao et al., 2000; Pinzari et al., 2002). Despite the documented drawbacks of this technique (Haack et al., 1995; Campbell et al., 1997; Smalla et al., 1998), its methodological simplicity has determined its implemen- tation in many European soil monitoring programmes (Nielse and Winding, 2002). Harmonizing the protocol would be important to allow inter-laboratory comparisons. In this communication, the effects of different soil storage methods on CLPPs are presented. Three soils, all representative of the semi-arid Mediter- ranean area, were selected: (1) a Typic Calcixerept under a pine plantation, (2) a Typic Calcixeroll under a pinewood with maquis and (3) a Typic Haploxerept under a grass steppe. Samples were taken in triplicate at two soil depths (0–10 cm and 10–20 cm) from each profile. All the samples had a pH of 8.5 (1:2.5 w/v) and a loamy texture, but substantially differed in their total organic carbon (TOC) content (Table 1), which was determined by oxidation with 1N potassium dichromate in acidic medium and back titration with 0.5N ammonium ferrous sulphate, as described by Walkey and Black (in Porta et al., 1986). The CLPPs were determined by the use of Biolog Ecoplates w (Garland and Mills, 1991; Insam, 1997; Insam and Goberna, 2004). Soil suspensions in Milli-Q water (1:10 w/v) were physically dispersed using a Waring blender (13,500 min K1 , 3 cycles!1 min, 4 8C). 0038-0717/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.soilbio.2004.06.014 Soil Biology & Biochemistry 37 (2005) 173–178 www.elsevier.com/locate/soilbio * Corresponding author. Tel.: C34-96-122-05-40; fax: C34-96-127- 09-67. E-mail address: marta.goberna@uv.es (M. Goberna).