2003), and tissue type (Van Alstyne et al. 1999). In algal studies, the analysis of tissue composition can be restricted by a limited availability of algal tissue—for example, where whole individuals of algae are smaller than the amount of tissue required for analyses, or where within-alga patterns of variation result in the scale of the traits measured being smaller than the scale of the tissue required for analyses. At present, combustion

analysis is predominately used for determination of carbon and nitrogen content in algal tissue, and the colorimetric Folin–Dennis method or Folin–Ciocalteus method is used to quantify phlorotannins. Although effective, these methods require relatively large amounts of tissue (∼1 g dry weight) and consume the sample tissue during analysis, making further Smoothened Agonist ic50 analyses of other constituents in the tissue impossible. Despite recent improvements in these methods (e.g., the development of 96-well microplate format by Zhang et al. 2006), the development of faster and more sample-efficient Rucaparib supplier protocols would enhance the ability of researchers to carry out more elaborate and probing experimental designs addressing the roles of phlorotannins and nutritional

traits in algae, especially in algal-mesoherbivore studies. This study aimed to (a) develop NIRS calibration models for carbon, nitrogen, and phlorotannins in the brown alga S. flavicans (Phaeophyta: Fucales); and (b) determine if NIRS could detect changes in the tissue composition of S. flavicans created by experimental manipulation of temperature and nutrient availability. Elevated nitrogen availability has previously

been shown to decrease phlorotannin content in algae (Yates and Peckol 1993, Hemmi et al. 2005, Svensson et al. 2007), due to increasing growth rates of individuals, thereby reducing from the pool of carbon-based photosynthates allocated to secondary metabolite production. We chose to manipulate temperature on the basis that, under unlimited resource conditions, production of enzymatic pathways associated with growth will increase with elevated temperatures, thereby increasing algal growth rates and reducing the carbon allocation to secondary metabolites. The experiment tested the two hypotheses that concentrations of phlorotannins will be lower under elevated nitrogen conditions and elevated temperatures. Study organism and collection details. Sargassum flavicans was collected from the rocky shore at Redcliffe, Moreton Bay, South East Queensland, Australia (27°3.2′ S; 153°06.7′ E). Sargassum tissue was collected from the shallow subtidal zone (1–1.5 m depth) where Sargassum is a dominant taxon within the algal community. To develop an NIRS calibration equation for phlorotannin content in Sargassum, 85 samples were collected from different Sargassum individuals in the field for phlorotannin content analysis.