| 1. |
- Liu, Yu, et al.
(författare)
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Tree-ring stable carbon isotope-based May-July temperature reconstruction over Nanwutai, China, for the past century and its record of 20th century warming
- 2014
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 93, s. 67-76
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Tidskriftsartikel (refereegranskat)abstract
- Growth anomaly of trees in some regions was detected under current episode of rapid warming. This raises a dilemma for temperature reconstructions by using tree-ring width which is believed to be the most important proxy on inter-annual temperature reconstruction during the past millenniums. Here we employed the tree-ring d13C to reconstruct temperature variations for exploring their potential on capturing signals of rapid warming, and to test how its difference with the tree-ring width based reconstruction. In this study the mean MayeJuly temperature (TMeJ) was reconstructed over the past century by tree-ring d13C of Chinese pine trees growing in the Nanwutai region. The explained variance of the reconstruction was 43.3% (42.1% after adjusting the degrees of freedom). Compared to a ring-width temperature reconstruction (MayeJuly) from the same site, the tree-ring d13C-based temperature reconstruction offered two distinct advantages: 1) it captured a wider range of temperature variability, i.e., at least MayeJuly, even over a longer part of the year, JanuaryeSeptember; and 2) the reconstruction preserved more low-frequency climate information than that of ring width did. The 20th century warming was well represented in the Nanwutai tree-ring d13C temperature reconstruction, which implied that stable carbon isotope of tree rings potentially represents temperature variations during historical episodes of rapid warming. A spatial correlation analysis showed that our temperature reconstruction represented climate variations over the entire Loess Plateau in north-central China. Significant positive correlations (p < 0.1) were found between the temperature reconstruction and ENSO, as well as SSTs in the Pacific and Indian Oceans. The reconstruction showed the periodicities of 22.78-, 4.16-, 3.45e3.97- and 2.04e2.83-year quasi-cycles at a 95% confidence level. Our results suggested that temperature variability in the Nanwutai region may be linked to Pacific and Indian Ocean SST variations and solar activity.
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| 2. |
- Schoch, Conrad L., et al.
(författare)
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Finding needles in haystacks: linking scientific names, reference specimens and molecular data for Fungi
- 2014
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Ingår i: Database: The Journal of Biological Databases and Curation. - : Oxford University Press (OUP). - 1758-0463. ; 2014:bau061, s. 1-21
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Tidskriftsartikel (refereegranskat)abstract
- DNA phylogenetic comparisons have shown that morphology-based species recognition often underestimates fungal diversity. Therefore, the need for accurate DNA sequence data, tied to both correct taxonomic names and clearly annotated specimen data, has never been greater. Furthermore, the growing number of molecular ecology and microbiome projects using high-throughput sequencing require fast and effective methods for en masse species assignments. In this article, we focus on selecting and re-annotating a set of marker reference sequences that represent each currently accepted order of Fungi. The particular focus is on sequences from the internal transcribed spacer region in the nuclear ribosomal cistron, derived from type specimens and/or ex-type cultures. Re-annotated and verified sequences were deposited in a curated public database at the National Center for Biotechnology Information (NCBI), namely the RefSeq Targeted Loci (RTL) database, and will be visible during routine sequence similarity searches with NR_prefixed accession numbers. A set of standards and protocols is proposed to improve the data quality of new sequences, and we suggest how type and other reference sequences can be used to improve identification of Fungi.
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