Woolnough and Foley (2002) validated the use of NIRS to determine the nutritive value of pasture available to the engaged northern hairy-nosed wombat over different seasons. NIRS has also been used to determine the effects

of herbivores on plant tissue. Stolter et al. (2006) used NIRS to measure the nitrogen, fiber, and specific and total phenolics in subarctic willows and demonstrated that NIRS could predict the effects of moose grazing on willow leaf chemistry the following season. Selleckchem CB-839 In the marine environment, NIRS has been used to measure important determinants of nutritional quality (including nitrogen, starch, carbohydrates, detergent fiber, and lignin) in seagrass species consumed by dugongs (Lawler et al. 2006) and to determine the effects of turtle and dugong grazing on the nutritional value of seagrass following grazing experiments (Aragones et al. 2006). However, despite the apparent diverse applications of NIRS, the use of NIRS to measure marine macroalgal traits has been limited to the measurement of alginate in the brown alga Laminaria hyperborean (Horn et al. 1999). This study aimed to test if NIRS could be used to accurately and

effectively measure three important traits associated with tissue quality in macroalgae: total nitrogen, total carbon, and phlorotannin content. The growth of marine macroalgae and their herbivores see more are frequently limited by nitrogen (Elser et al. 2007). As a consequence, the relative concentration of nitrogen to carbon in macroalgal tissue is commonly used as a proxy for nutritional value to herbivores (Yates and Peckol 1993, Cruz-Rivera and Hay 2000, Hemmi and Jormalainen 2002). Tissue carbon and nitrogen concentrations in macroalgae vary as a function of resource availability, including nutrients and light, and can vary among tissues at small scales (e.g., centimeters) (Arnold et al. 1995, Edwards et al. 2006). To understand the mechanisms governing algal growth and algal-herbivore

interactions, it is important to measure these plastic plant-quality components in macroalgae. Phlorotannins are polyphenolics found exclusively in the Phaeophyceae (brown algae) and are a subgroup of tannins that are acetate-malonate (polyketide) derived polymers of phoroglucinol (1,3,5-trihydroxybenzene) MCE公司 (Ragan and Glombitza 1986). These water-soluble phlorotannins have been found to occur in concentrations of up to 25% of dry weight, and along with their putative roles in cell-wall construction, phlorotannins can fulfill a number of ecological roles, such as protection from ultraviolet radiation, fouling organisms, or herbivores (reviewed in Paul et al. 2006, Amsler 2008, Paul and Ritson-Williams 2008). Phlorotannin concentrations are highly variable, varying over geographic regions (Steinberg 1986, Targett and Arnold 1998), species (Stiger et al. 2004, Fairhead et al. 2005), and individuals (Tuomi et al. 1989).