Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e., continuous culture) experiments. We quantified linkages among δ13C, nutrients, carbonate chemistry, primary, and seconda...

Because of the importance of hydraulic architecture in understanding physiological differences between small and large trees, we tested the hypothesis that foliar δ13C increased with aboveground flow-path length in longleaf pine (Pinus palustris Mill.) trees of varying age and size at two sites in the lower Coastal Plain. This species offered a unique opportunity to examine variability in folia...

Stable isotopes are increasingly used to infer sources of nutrient enrichment and trophic linkages in coastal marine systems, although the utility of these tools often depends upon a predictable expression of δ15N and δ13C signatures by primary producers. Accordingly, we examined how tissue δ15N and δ13C values change in the common coastal marine alga Ulva pertusa Kjellman under contrasting lig...

The importance of organic matter produced in seagrass meadows (seagrass and epiphytic algae) to the nutrition of a valuable fisheries species (yellowfin whiting Sillago schomburgkii Peters) occurring over unvegetated mudflats was measured using the isotopic composition (δ13C, δ15N) of fish, their polychaete prey, and available autotrophic sources at several locations in southern Australia durin...

To investigate the applicability of compound specific stable carbon isotope ratios (δ13C) of organics in assessment of their photochemical aging in the atmosphere, batch UV irradiation experiments were conducted on two ambient (anthropogenic and biogenic) aerosol samples in aqueous phase for 0.5-120 h. The irradiated samples were analyzed for δ13C of diacids, glyoxylic acid (ωC2) and glyoxal. δ...

Plants adopt ecological strategy to resist environmental changes and increase their resource-use efficiency. The ecological strategy includes changes in physiological traits and leaf morphology, which may result in simultaneous variations in foliar N concentration and the ratio of intercellular CO2 concentration to ambient CO2 concentration (ci/ca). This in turn links to foliar carbon isotope d...

Mercury bioaccumulation is frequently observed in marine ecosystems, often with stronger effects at higher trophic levels. We compared total mercury (THg) and methylmercury (MeHg) from muscle with length, comparative isotopic niche, and diet (via δ13C and δ15N) among four sympatric coastal sharks in Florida Bay (USA): blacknose, blacktip, bull, and lemon. Mercury in blacknose and blacktip shark...

The natural abundance of stable carbon isotope values (δ13C) of organic matter of marine macroalgae collected from Taiwan and its offshore islands (Penghu Islands) were analyzed in this study. These values ranged from -10.5 to -29.5‰. The highest δ13C value came from green algae (-10.5‰), Ulva pertusa while most algae exhibited values in the -14 to -19‰ range. On average, the δ13C values of red...

Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasi...

Tunable diode laser absorption spectrometry (TDLAS) is gaining in popularity for measuring the mole fraction [CO2] and stable isotopic composition (δ13C) of carbon dioxide (CO2) in air in studies of biosphere-atmosphere gas exchange. Here we present a detailed examination of the performance of a commercially-available TDLAS located in a high-altitude subalpine coniferous forest (the Niwot Ridge...