Creating Community for Early-Career Geoscientists:Student involvement in geoscience unions: A case study from hydrology

The American Geophysical Union (AGU) and the European Geosciences Union (EGU) play central roles in nurturing the next generation of geoscientists. Students and young scientists make up about one-quarter of the unions’ active memberships [American Geophysical Union, 2013; European Geosciences Union, 2014], creating a major opportunity to include a new generation of geoscientists as more active contributors to the organizations’ activities, rather than merely as consumers

The Role of Polyphosphate Accumulating Organisms in Environmental Phosphorus Cycling

Phosphorus (P) is a limiting nutrient in freshwater ecosystems and excess P from anthropogenic sources impairs water quality. Strategies to manage P pollution depend on abiotic and well as biotic mechanisms. For example, no till farming practices physically reduce transport of sediment-bound P into nearby waterbodies and specialized wastewater treatment plants (WWTPs) utilize biological (i.e., microbial) mechanisms to remove P from influent waters. With respect to the latter, the main actors of these specialized WWTPs are a group of organisms known as polyphosphate accumulating organisms (PAOs). PAOs are well studied in the context of WWTPs and a limited number of studies have identified them in the natural environment. However, very little is known about their ecological role as well as their influence on P cycling and transport in natural systems. Therefore, the overall goal of this work was to expand our understanding of PAOs in soils and streams. We started this exploration with a review of PAOs in engineered and natural systems—we discussed knowledge gaps and ways studies from these distinct contexts may build on one another. This review also included a discussion of the potential role of PAOs in agricultural systems. We proposed studies to explore the impacts of PAOs in terms of major agricultural challenges and discussed how these studies may inform our understanding of PAOs in engineered and natural systems. Next, we conducted a laboratory experiment to explore the role of PAO-mediated P cycling in stream biofilms under alternating aerobic and anaerobic conditions. We demonstrated cyclical patterns of P uptake under aerobic conditions and release during anaerobic conditions, which is consistent with the known behavior of PAOs in WWTPs. We also verified larger percentages of cells with stored intracellular polyphosphate granules under aerobic conditions compared to anaerobic conditions, which we expected given our understanding of the PAO phenotype in WWTPs. However, we observed concurrent patterns in cation uptake and release, which may indicate abiotic precipitation/dissolution of P with these cations and/or biotic uptake/release of these cations to balance the negative charge of intracellular polyP. Next, we explored whether the soil wetness index (SWI), a static index used to predict landscape scale soil moisture patterns, can predict the occurrence of mobile forms of P as well as PAO associated functional genes (i.e., ppk1, ppk2, and ppx). We showed that SWI predicted mobile P (i.e., dilute CaCl2 extractable P) and there was a depletion of mobile P from wetter parts of the landscape. This is consistent with our expectations of PAO behavior; PAOs release mobile forms of P under saturated conditions that are transported off-site. More specifically related to PAOs, we found that SWI was not a good predictor of the relative abundance of polyP functional genes. We observed a general decrease in the relative abundance polyP functional genes versus mobile P concentrations in NY, was consistent with our hypothesis, but this trend was only statistically significant in the case of ppk2. In PA, the relationship between the relative abundance of polyP functional genes was not significant and general trends were inconsistent with our hypothesis. Therefore, these results suggest the limited role of PAO-mediated P cycling along the SWI gradients identified and the potential masking of PAOs by other P controls (e.g. landscape position and management). Future research may consider how the role of biotic and abiotic processes masks the role of PAOs in soil P cycling. These includes the impact of iron reducing bacteria or chemical iron reduction/dissolution with P along a SWI gradient. Despite this limited support for PAOs, we identified contigs harboring both ppk1 and ppx genes that were within the same phyla as known PAOs as well as many unstudied, putative PAOs. Last, we studied whether PAOs played a discernable role in P cycling associated with the decomposition of leaf litter in the stream and on the forest floor. We observed an increase in leaf P concentrations in the stream and a decrease in leaf P concentrations on the forest floor over time. Unexpectedly, we did not observe a concurrent increase in the relative abundance of PAO-associated functional genes over time in the stream. Rather these genes remained constant. ppk1 and ppx relative abundances also remained constant in the forest floor but the relative abundance of ppk2 genes increased over time. While these trends did not provide support for PAOs control on P cycling in leaf litter decomposition, we identified contigs harboring both ppk1 and ppx genes that were within the same phyla as known PAOs as well as many unstudied, putative PAOs just as we observed in the soil study. In the case of both soil and leaf litter experiments, future studies may consider using microscopy and molecular biology tools to verify whether putative PAOs exhibit the phenotype of PAO established in engineered systems. Overall, we found support for PAO-mediated P cycling in stream biofilms but only limited support for their impact on P cycling in soils along a SWI gradient as well as on decomposing leaf P patterns over time. We provided additional thoughts at the end of the review paper and in chapter five on how these studies can be modified to test for the potential role of PAOs in agricultural P management as well as the influence of hydrology and nutrient demand/availability on PAO-mediated P cycling

Critical Review of Polyphosphate and Polyphosphate Accumulating Organisms for Agricultural Water Quality Management

Despite ongoing management efforts, phosphorus (P) loading from agricultural landscapes continues to impair water quality. Wastewater treatment research has enhanced our knowledge of microbial mechanisms influencing P cycling, especially regarding microbes known as polyphosphate accumulating organisms (PAOs) that store P as polyphosphate (polyP) under oxic conditions and release P under anoxic conditions. However, there is limited application of PAO research to reduce agricultural P loading and improve water quality. Herein, we conducted a meta-analysis to identify articles in Web of Science on polyP and its use by PAOs across five disciplines (i.e., wastewater treatment, terrestrial, freshwater, marine, and agriculture). We also summarized research that provides preliminary support for PAO-mediated P cycling in natural habitats. Terrestrial, freshwater, marine, and agriculture disciplines had fewer polyP and PAO articles compared to wastewater treatment, with agriculture consistently having the least. Most meta-analysis articles did not overlap disciplines. We found preliminary support for PAOs in natural habitats and identified several knowledge gaps and research opportunities. There is an urgent need for interdisciplinary research linking PAOs, polyP, and oxygen availability with existing knowledge of P forms and cycling mechanisms in natural and agricultural environments to improve agricultural P management strategies and achieve water quality goals

Ten simple rules for researchers who want to develop web apps

Web applications, also known as web apps, are increasingly common in the research communication portfolios of those working in the life sciences (e.g., [1]) and physical sciences (e.g., [2–4]). Web apps help disseminate research findings and present research outputs in ways that are accessible and meaningful to the general public—from individuals, to governments, to companies. Specifically, web apps enable exploration of scenario testing and policy analysis (i.e., to answer “what if?”) as well as coevolution of scientific and public knowledge [5,6]. However, the majority of researchers developing web apps receive little formal training or technical guidance on how to develop and evaluate the effectiveness of their web-based decision support tools. Take some of us for example. We (Saia and Nelson) are agricultural and environmental engineers with little experience in web app development, but we are interested in creating web apps to support sustainable aquaculture production in the Southeast. We had user (i.e., shellfish growers) interest, a goal in mind (i.e., develop a new forecast product and decision support tool for shellfish aquaculturalists), and received funding to support this work. Yet, we experienced several unexpected hurdles from the start of our project that ended up being fairly common hiccups to the seasoned web app developers among us (Parham). As a result, we share the following 10 simple rules, which highlight take-home messages, including lessons learned and practical tips, of our experience as burgeoning web app developers. We hope researchers interested in developing web apps draw insights from our (in)experience as they set out on their decision support tool development journey

A4. A Web-Based BMP Selection Tool to Minimize Pesticide Transport

Farmers rely on best management practices to reduce pesticide transport to surface waters and groundwater. There are a variety of tools available to help soil and water conservation managers optimize agricultural best management practices (BMPs), but many require a considerable amount of time to calibrate and/or advanced training to use. More often than not, these same BMP tools also fail to accurately identify dominant hydrological processes, and thus, the location of runoff generating areas. More specifically, commonly used BMP selection tools are capable of predicting either infiltration excess runoff or saturation excess runoff but not both. Many studies have shown that saturated areas in the landscape are more likely to contribute dissolved and sediment bound contaminates. Therefore, an easy-to-use tool that can accurately characterize local hydrology is needed to assist soil and water managers as they work to target management practices and reduce pesticides transport. In this study we present a simple online BMP selection tool and compare simulated versus observed atrazine loads under different tillage conditions in the Goodwater Creek Watershed of northeastern Missouri. Results indicate a reasonable fit for runoff and dissolved atrazine concentrations but more research is needed to improve the accuracy and usability of this tool

Phosphate oxygen isotope ratios in vegetated riparian buffer strip soils

The oxygen isotopic composition of phosphate (δ18OP) in soils and surface water bodies has been used to trace terrestrial P inputs into aquatic ecosystems. However, enhanced biological activity in vegetated riparian buffer strips (VBSs) may lead to an alteration of δ18OP values. The objective of this study was to assess whether enhanced biological cycling of P in VBS soils can be identified using δ18OP values. For this purpose, we sampled temperate grassland soils at various depths along a VBS to grassland transect. Here, we combined sequential P soil extracts with an analysis of δ18OP values. Soil P pool concentrations tended to decrease significantly along the transect from the VBS to the grassland soils; the strength of this relationship varied with P extract, sample depth, and inorganic or organic bonding form. For the δ18OP values of the 1 M HCl-extractable P we observed a significant negative trend along the VBS to grassland transect, indicating a tendency for accelerated rates of biological cycling of P within the VBS soil profile compared with the upslope soils. We conclude that oxygen isotope-based assessments of P source contributions to freshwater bodies should consider the enhanced biological turnover of P in VBS soils.ISSN:1539-166

A hydrologist's guide to open science

Open, accessible, reusable, and reproducible hydrologic research can have a significant positive impact on the scientific community and broader society. While more individuals and organizations within the hydrology community are embracing open science practices, technical (e.g., limited coding experience), resource (e.g., open access fees), and social (e.g., fear of weaknesses being exposed or ideas being scooped) challenges remain. Furthermore, there are a growing number of constantly evolving open science tools, resources, and initiatives that can be overwhelming. These challenges and the ever-evolving nature of the open science landscape may seem insurmountable for hydrologists interested in pursuing open science. Therefore, we propose the general “Open Hydrology Principles” to guide individual and community progress toward open science for research and education and the “Open Hydrology Practical Guide” to improve the accessibility of currently available tools and approaches. We aim to inform and empower hydrologists as they transition to open, accessible, reusable, and reproducible research. We discuss the benefits as well as common open science challenges and how hydrologists can overcome them. The Open Hydrology Principles and Open Hydrology Practical Guide reflect our knowledge of the current state of open hydrology; we recognize that recommendations and suggestions will evolve and expand with emerging open science infrastructures, workflows, and research experiences. Therefore, we encourage hydrologists all over the globe to join in and help advance open science by contributing to the living version of this document and by sharing open hydrology resources in the community-supported repository (https://open-hydrology.github.io, last access: 1 February 2022).Water Resource

AEMON-J/DSOS Archive: "Hacking Limnology" Workshop + Virtual Summit in Data Science & Open Science in Aquatic Research

This OSF project is meant to serve as a long-term storage repository for presentations and workshop materials for the Aquatic Ecosystem Modeling-Junior (AEMON-J) and Virtual Summit: Incorporating Data Science and Open Science (DSOS) communities. Contributors in this repository include past presenters and workshop organizers. Contributors are only responsible for those individual presentations that are labeled with their surname