| 1. |
- Kattge, Jens, et al.
(författare)
-
TRY plant trait database - enhanced coverage and open access
- 2020
-
Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
-
Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
|
|
| 2. |
- Hrdina, Amy, et al.
(författare)
-
The role of coarse aerosol particles as a sink of HNO3 in wintertime pollution events in the Salt Lake Valley
- 2021
-
Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 21:10, s. 8111-8126
-
Tidskriftsartikel (refereegranskat)abstract
- Wintertime ammonium nitrate (NH4NO3) pollution events burden urban mountain basins around the globe. In the Salt Lake Valley of Utah in the United States, such pollution events are often driven by the formation of persistent cold-air pools (PCAPs) that trap emissions near the surface for several consecutive days. As a result, secondary pollutants including fine particulate matter less than 2.5 um in diameter (PM2:5), largely in the form of NH4NO3, build up during these events and lead to severe haze. As part of an extensive measurement campaign to understand the chemical processes underlying PM2:5 formation, the 2017 Utah Winter Fine Particulate Study, water-soluble trace gases and PM2:5 constituents were continuously monitored using the ambient ion monitoring ion chromatograph (AIM-IC) system at the University of Utah campus. Gas-phase NH3, HNO3, HCl, and SO2 along with particulate NHC 4 , NaC, KC, Mg2C, Ca2C, NO3 , Cl, and SO2 4 were measured from 21 January to 21 February 2017. During the two PCAP events captured, the fine particulate matter was dominated by secondary NH4NO3. The comparison of total nitrate (HNO3 CPM2:5 NO3 ) and total NHx (NH3 CPM2:5 NHC 4 ) showed NHx was in excess during both pollution events. However, chemical composition analysis of the snowpack during the first PCAP event revealed that the total concentration of deposited NO3 was nearly 3 times greater than that of deposited NHC 4 . Daily snow composition measurements showed a strong correlation between NO3 and Ca2C in the snowpack. The presence of non-volatile salts (NaC, Ca2C, and Mg2C), which are frequently associated with coarse-mode dust, was also detected in PM2:5 by the AIM-IC during the two PCAP events, accounting for roughly 5% of total mass loading. The presence of a significant particle mass and surface area in the coarse mode during the first PCAP event was indicated by size-resolved particle measurements from an aerodynamic particle sizer. Taken together, these observations imply that atmospheric measurements of the gas-phase and fine-mode particle nitrate may not represent the total burden of nitrate in the atmosphere, implying a potentially significant role for uptake by coarse-mode dust. Using the NO3 :NHC 4 ratio observed in the snowpack to estimate the proportion of atmospheric nitrate present in the coarse mode, we estimate that the amount of secondary NH4NO3 could double in the absence of the coarse-mode sink. The underestimation of total nitrate indicates an incomplete account of the total oxidant production during PCAP events. The ability of coarse particles to permanently remove HNO3 and influence PM2:5 formation is discussed using information about particle composition and size distribution.
|
|
| 3. |
|
|
| 4. |
- Denk, Thomas, et al.
(författare)
-
Genomic landscape of the global oak phylogeny
- 2019
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; , s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- The tree of life is highly reticulate, with the history of population divergence emerging frompopulations of gene phylogenies that reflect histories of introgression, lineage sorting anddivergence. In this study, we investigate global patterns of oak diversity and test the hypothesisthat there are regions of the oak genome that are broadly informative about phylogeny. We utilize fossil data and restriction-site associated DNA sequencing (RAD-seq) for 632individuals representing nearly 250 Quercus species to infer a time-calibrated phylogeny ofthe world’s oaks. We use a reversible-jump Markov chain Monte Carlo method to reconstructshifts in lineage diversification rates, accounting for among-clade sampling biases. We thenmap the > 20 000 RAD-seq loci back to an annotated oak genome and investigate genomicdistribution of introgression and phylogenetic support across the phylogeny. Oak lineages have diversified among geographic regions, followed by ecological divergencewithin regions, in the Americas and Eurasia. Roughly 60% of oak diversity traces back to fourclades that experienced increases in net diversification, probably in response to climatic transitionsor ecological opportunity. The strong support for the phylogeny contrasts with high genomic heterogeneity in phylogeneticsignal and introgression. Oaks are phylogenomic mosaics, and their diversity may infact depend on the gene flow that shapes the oak genome.
|
|
