Citizen science for water quality monitoring: Data implications of citizen perspectives.

Citizen science, where citizens play an active role in the scientific process, is increasingly used to expand the reach and scope of scientific research while also achieving engagement and educational goals. Despite the emergence of studies exploring data outcomes of citizen science, the process and experience of engaging with citizens and citizen-lead groups through participatory science is less explored. This includes how citizen perspectives alter data outcomes, a critical upshot given prevalent mistrust of citizen versus scientist data. This study uses a citizen science campaign investigating watershed impacts on water quality to interrogate the nature and implications of citizen involvement in producing scientifically and societally relevant data. Data representing scientific outcomes are presented alongside a series of vignettes that offer context regarding how, why, and where citizens engaged with the project. From these vignettes, six specific lessons are examined towards understanding how integration of citizen participation alters data outcomes relative to 'professional' science. In particular, elements of participant social identity (e.g., their motivation for participation), and contextual knowledge (e.g., of the research program itself) can shape participation and resulting data outcomes. Such scientific outcomes are particularly relevant given continued concerns regarding the quality of citizen data, which could hinder scientific acceptance of citizen sciences. Importantly, the potential for meaningful engagement with citizen and participants within citizen groups - given significant capacity within the community - represents a substantial and under-realized opportunity.

Nitrogen enrichment potential of biochar in relation to pyrolysis temperature and feedstock quality.

Nitrogen (N) enrichment of biochar from both inorganic and organic waste N sources has the potential to add economic and environmental value through its use as a slow release N fertilizer. We investigated the sorption of N by, and its release from, biochar made at pyrolysis temperatures of 400, 500 and 600 °C from three feedstocks: poultry litter (PL with a carbon (C) to N ratio (C:N) of 14), softwood chips of spruce-pine-fir (SPF with a C:N of 470), and a 50:50 mixture of PL and SPF (PL/SPF). The prepared biochars were enriched with ammonium nitrate (AN) and urea ammonium nitrate (UAN). PL biochars had the lowest C content (50-56% C), but the highest pH (9.3-9.9), electrical conductivity (EC, 780-960 dS m(-1)), cation exchange capacity (CEC, 40-46 cmol kg(-1)), and N content (3.3-4.5%). While N content and hydrogen (H) to C atomic ratio (H:C) decreased with increasing pyrolysis temperature irrespective of the feedstock used, both pH and EC slightly increased with pyrolysis temperature for all feedstocks. The PL and SPF biochars showed similar H:C and also similar N sorption and N release at all pyrolysis temperatures. These biochars sorbed up to 5% N by mass, irrespective of the source of N. However, PL/SPF biochar performed poorly in sorbing N from either AN or UAN. Biochar H:C was found to be unrelated to N sorption rates, suggesting that physical adsorption on active surfaces was the main mechanism of N sorption in these biochars. There were minor differences between N sorbed from NO3-N and NH4-N among different biochars. Very small amounts of sorbed N (0.2-0.4 mg N g(-1) biochar) was released when extracted with 1 M KCl solution, indicating that the retained N was strongly held in complex bonds, more so for NH4-N because the release of NO3-N was 3-4 times greater than that of NH4-N. NH4-N sorption far exceeded the effective CEC of the biochars, thereby suggesting that most of the sorption may be due to physical entrapment of NH4(+) in biochar pores. The results of this study suggest that biochar can be used to remove excess N from poultry and dairy manure and be a good mitigation option for reducing N leaching and gaseous losses.

Submersible UV-Vis spectroscopy for quantifying streamwater organic carbon dynamics: implementation and challenges before and after forest harvest in a headwater stream.

Organic material, including total and dissolved organic carbon (DOC), is ubiquitous within aquatic ecosystems, playing a variety of important and diverse biogeochemical and ecological roles. Determining how land-use changes affect DOC concentrations and bioavailability within aquatic ecosystems is an important means of evaluating the effects on ecological productivity and biogeochemical cycling. This paper presents a methodology case study looking at the deployment of a submersible UV-Vis absorbance spectrophotometer (UV-Vis spectro::lyzer model, s::can, Vienna, Austria) to determine stream organic carbon dynamics within a headwater catchment located near Campbell River (British Columbia, Canada). Field-based absorbance measurements of DOC were made before and after forest harvest, highlighting the advantages of high temporal resolution compared to traditional grab sampling and laboratory measurements. Details of remote deployment are described. High-frequency DOC data is explored by resampling the 30 min time series with a range of resampling time intervals (from daily to weekly time steps). DOC export was calculated for three months from the post-harvest data and resampled time series, showing that sampling frequency has a profound effect on total DOC export. DOC exports derived from weekly measurements were found to underestimate export by as much as 30% compared to DOC export calculated from high-frequency data. Additionally, the importance of the ability to remotely monitor the system through a recently deployed wireless connection is emphasized by examining causes of prior data losses, and how such losses may be prevented through the ability to react when environmental or power disturbances cause system interruption and data loss.

Measuring "unmeasurable" folding kinetics of proteins by single-molecule force spectroscopy.

Folding and unfolding are fundamental biological processes in cell and are important for the biological functions of proteins. Characterizing the folding and unfolding kinetics of proteins is important for understanding the energetic landscape leading to the active native conformations of these molecules. However, the thermal or chemical-induced unfolding of many proteins is irreversible in vitro, precluding characterization of the folding kinetics of such proteins, just as it is impossible to "un-boil" an egg. Irreversible unfolding often manifests as irreversible aggregation of unfolded polypeptide chains, which typically occurs between denatured protein molecules in response to the exposure of hydrophobic residues to solvent. An example of such a protein where thermal denaturation results in irreversible aggregation is the ß-1,4 endoxylanase from Bacillus circulans (BCX). Here, we report the use of single-molecule atomic force microscopy to directly measure the folding kinetics of BCX in vitro. By mechanically unfolding BCX, we essentially allowed only one unfolded molecule to exist in solution at a given time, effectively eliminating the possibility for aggregation. We found that BCX can readily refold back to the native state, allowing us to measure its folding kinetics for the first time. Our results demonstrate that single-molecule force-spectroscopy-based methods can adequately tackle the challenge of "un-boiling eggs", providing a general methodology to characterize the folding kinetics of many proteins that suffer from irreversible denaturation and thus cannot be characterized using traditional equilibrium methodologies.

Nanomechanical properties of tenascin-X revealed by single-molecule force spectroscopy.

Tenascin-X is an extracellular matrix protein and binds a variety of molecules in extracellular matrix and on cell membrane. Tenascin-X plays important roles in regulating the structure and mechanical properties of connective tissues. Using single-molecule atomic force microscopy, we have investigated the mechanical properties of bovine tenascin-X in detail. Our results indicated that tenascin-X is an elastic protein and the fibronectin type III (FnIII) domains can unfold under a stretching force and refold to regain their mechanical stability upon the removal of the stretching force. All the 30 FnIII domains of tenascin-X show similar mechanical stability, mechanical unfolding kinetics, and contour length increment upon domain unfolding, despite their large sequence diversity. In contrast to the homogeneity in their mechanical unfolding behaviors, FnIII domains fold at different rates. Using the 10th FnIII domain of tenascin-X (TNXfn10) as a model system, we constructed a polyprotein chimera composed of alternating TNXfn10 and GB1 domains and used atomic force microscopy to confirm that the mechanical properties of TNXfn10 are consistent with those of the FnIII domains of tenascin-X. These results lay the foundation to further study the mechanical properties of individual FnIII domains and establish the relationship between point mutations and mechanical phenotypic effect on tenascin-X. Moreover, our results provided the opportunity to compare the mechanical properties and design of different forms of tenascins. The comparison between tenascin-X and tenascin-C revealed interesting common as well as distinguishing features for mechanical unfolding and folding of tenascin-C and tenascin-X and will open up new avenues to investigate the mechanical functions and architectural design of different forms of tenascins.