Isotopic and molecular distributions of biochemicals from fresh and buried
| Autor: | Myrna E. Jacobson, Marilyn L. Fogel, Barbara J. Smallwood, Matthew J. Wooller |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
lcsh:GE1-350
musculoskeletal diseases Paper biology δ13C chemistry.chemical_element Fractionation δ15N biology.organism_classification Nitrogen Isotopes of nitrogen lcsh:Chemistry Nutrient chemistry lcsh:QD1-999 Geochemistry and Petrology Botany Mangrove Rhizophora mangle lcsh:Environmental sciences |
| Zdroj: | Geochemical Transactions Geochemical Transactions, Vol 4, Iss 1, p 38 (2003) |
| ISSN: | 1467-4866 |
| Popis: | Rhizophora mangle L. (red mangrove) is the dominant species of mangrove in the Americas. At Twin Cays, Belize (BZ) red mangroves are present in a variety of stand structures (tall >5 m in height, transition ~2–4 m and dwarf ~1–1.5 m). These height differences are coupled with very different stable carbon and nitrogen isotopic values1 (mean tall δ13C = -28.3‰, δ15N = 0‰; mean tall δ13C = -25.3‰, δ15N = -10‰). To determine the utility of using these distinct isotopic compositions as 'biomarkers' for paleoenvironmental reconstruction of mangrove ecosystems and nutrient availability, we investigated the distribution and isotopic (δ13C and δ15N) composition of different biochemical fractions (water soluble compounds, free lipids, acid hydrolysable compounds, individual amino acids, and the residual un-extractable compounds) in fresh and preserved red mangrove leaves from dwarf and tall trees. The distribution of biochemicals are similar in dwarf and tall red mangrove leaves, suggesting that, regardless of stand structure, red mangroves use nutrients for biosynthesis and metabolism in a similar manner. However, the δ13C and δ15N of the bulk leaf, the biochemical fractions, and seven amino acids can be used to distinguish dwarf and tall trees at Twin Cays, BZ. The data support the theory that the fractionation of carbon and nitrogen occurs prior to or during uptake in dwarf and tall red mangrove trees. Stable carbon and nitrogen isotopes could, therefore, be powerful tools for predicting levels of nutrient limitation at Twin Cays. The δ13C and δ15N of biochemical fractions within preserved leaves, reflect sedimentary cycling and nitrogen immobilization. The δ15N of the immobilized fraction reveals the overlying stand structure at the time of leaf deposition. The isotopic composition of preserved mangrove leaves could yield significant information about changes in ecosystem dynamics, nutrient limitation and past stand structure in mangrove paleoecosystems. |
| Databáze: | OpenAIRE |
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