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Among biocollections, mollusks are a particularly powerful resource for a wide range of studies, including biogeography, conservation, ecology, environmental monitoring, evolutionary biology, and systematics. U.S. mollusk collections are housed in stand-alone natural history museums, at universities, and in a variety of governmental and non-governmental institutions. Differing in their histories, specializations, and uses, they share common needs for long-term development, and collectively contribute to biodiversity knowledge at regional, national, and global scales. Commitment by dedicated staff, collectors, and volunteers, institutional investments, philanthropy, and governmental funding have built and maintained these collections and their support infrastructure. Efforts by the North American malacological collection community since the early 1970s led to coordination in database design but left the data isolated in individual institutions. Collection digitization developed through a combination of individual/institutional initiatives and federally supported projects funded by the National Science Foundation (NSF) and the Institute of Museum and Library Services (IMLS). Advances in digital technology enabled the shift toward nationally and globally unified collections. Networking and collaboration were greatly accelerated by NSF’s Advancing Digitization of Biodiversity Collections (ADBC) program, which created a central coordinating organization (iDigBio) and funded Thematic Collections Network (TCN) projects. One such TCN was developed to mobilize nearly 90% of the known U.S. museum-collections-based data of the U.S. Atlantic and Gulf coasts (Mobilizing Millions of Marine Mollusks of the Eastern Seaboard—ESB). The project, involving 16 museum collections (plus the Smithsonian Institution as federal partner), combines data from approximately 4.5 million specimens collected from the ESB region and makes them available to the TCN portal InvertEBase and other aggregators such as iDigBio and GBIF. In addition to fostering community and expanding the corpus of available digitized mollusk records through new data entry and georeferencing (GEOLocate, CoGe) and standardizing taxonomy, the project drove key innovations for the invertebrate collections community. For instance, it worked with the Biodiversity Information Standards (TDWG) group to create a new Darwin Core standard term, “Vitality”, expanded GEOLocate to support complex geospatial types, integrated global elevation and bathymetric datasets directly into georeferencing workflow, and developed various education and outreach public outreach products. Synthesizing from the 15 following articles with individual histories of ESB-participating mollusk collections, several topics are discussed—such as what defines a “good” mollusk collection in the digital age and the importance of federal support for this national resource. 

Future climate change may bring local benefits or penalties to surface air pollution, resulting from changing temperature, precipitation, and transport patterns, as well as changes in climate-sensitive natural precursor emissions. Here, we estimate the climate penalties and benefits at the end of this century with regard to surface ozone and fine particulate matter (PM ${}_{2.5}$; excluding dust and smoke) using a one-way offline coupling between a general circulation model and a global 3-D chemical-transport model. We archive meteorology for the present day (2005 to 2014) and end of this century (2090 to 2099) for seven future scenarios developed for Phase 6 of the Coupled Model Intercomparison Project. The model isolates the impact of forecasted anthropogenic precursor emission changes versus that of climate-only driven changes on surface ozone and PM ${}_{2.5}$for scenarios ranging from extreme mitigation to extreme warming. We then relate these changes to impacts on human mortality and crop production. We find ozone penalties over nearly all land areas with increasing warming. We find net benefits due to climate-driven changes in PM ${}_{2.5}$in the Northern Extratropics, but net penalties in the Tropics and Southern Hemisphere, where most population growth is forecast for the coming century. 

Two series of lactone-terminated alkanethiol adsorbates with five- and six-membered lactone groups, γ-COCnSH and δ-COCnSH (n = 11, 12), were synthesized and employed to create nanoscale self-assembled monolayers (SAMs) on gold substrates to mimic the properties of commercially available poly(lactic-co-glycolic acid) (PLGA) and poly(glycolic acid) (PGA) surfaces. 1H and 13C nuclear magnetic resonance (NMR) were employed to characterize the adsorbate molecules. The thicknesses of the corresponding self-assembled monolayers (SAMs) were evaluated by ellipsometry. The conformational characteristics of the SAMs were analyzed using polarization modulation infrared reflection adsorption spectroscopy (PM-IRRAS), with a focus on the C-H antisymmetric stretching vibrations of the alkyl spacers. To evaluate the packing densities of the monolayers, X-ray photoelectron spectroscopy (XPS) measurements were performed. Separately, contact angle measurements provided insights into the wettability of the surfaces. Remarkably, the contact angle data across a broad range of probe liquids for the γ-COC11SH and γ-COC12SH SAMs were consistently similar to each other and to the contact angle values of the PLGA surface, rather than to PGA. This finding suggests that the lactone-terminated SAMs investigated in this study effectively mimic nanoscale polyester surfaces, enabling the exploration of interfacial properties of polyesters in the absence of swelling and/or surface reconstruction phenomena. 

Molecular interactions at interfaces have a significant effect on the wetting properties of surfaces on a macroscale. 

Abstract. Despite significant precursor emission reductions in theUS over recent decades, atmospheric nitrate deposition remains an importantterrestrial stressor. Here, we utilized statistical air mass back trajectoryanalysis and nitrogen stable isotope deltas (δ(15N)) toinvestigate atmospheric nitrate spatiotemporal trends in the northeastern USfrom samples collected at three US EPA Clean Air Status and Trends Network(CASTNET) sites from December 2016–2018. For the considered sites, similarseasonal patterns in nitric acid (HNO3) and particulate nitrate(pNO3) concentrations were observed with spatial differences attributedto nitrogen oxide (NOx) emission densities in source contributingregions that were typically ≤ 1000 km. Significant spatiotemporalδ(15N) variabilities in HNO3 and pNO3 were observedwith higher values during winter relative to summer, like previous reportsfrom CASTNET samples collected in the early 2000s for our study region. Inthe early 2000s, δ(15N) of atmospheric nitrate in the northeastUS had been suggested to be driven by NOx emissions; however, we didnot find significant spatiotemporal changes in the modeled NOxemissions by sector and fuel type or δ(15N, NOx) for thesource regions of the CASTNET sites. Instead, the seasonal and spatialdifferences in the observed δ(15N) of atmospheric nitrate weredriven by nitrate formation pathways (i.e., homogeneous reactions ofNO2 oxidation via hydroxyl radical or heterogeneous reactions ofdinitrogen pentoxide on wetted aerosol surfaces) and their associatedδ(15N) fractionation. Under the field conditions of lowNOx relative to O3 concentrations and when δ(15N,NOx) emission sources do not have significant variability, wedemonstrate that δ(15N) of atmospheric nitrate can be a robusttracer for diagnosing nitrate formation.