Low-level dissolved organic carbon subsidies drive a trophic upsurge in a boreal stream

1. Energy pathways in stream food webs are often driven by allochthonous basal resources. However, allochthonous dissolved organic carbon (DOC) is generally viewed as a minor if not insignificant basal resource because much of the DOC pool comprises high molecular weight, recalcitrant compounds and is inefficiently incorporated into biomass. Nevertheless, there is increasing evidence that the relatively small, labile fraction of DOC may indeed fuel microbial activity to a level that stimulates productivity across multiple trophic levels, resulting in a trophic upsurge. Here, we tested the trophic upsurge hypothesis by subsidising the labile DOC pool of an Alaskan boreal stream that had relatively high nutrient availability but low levels of naturally occurring DOC. 2. We continuously added ecologically relevant (0.250 mg C/L, c. 10% increase above ambient bulk DOC) concentrations of labile DOC (acetate-C) for 62 days to a treatment reach that was statistically indistinguishable in its channel form and chemistry from an upstream reference reach. We measured responses of pe-riphyton production and biomass, whole reach metabolism and nutrient uptake, benthic invertebrate abundances, and juvenile salmonid (Dolly Varden, Salvelinus malma) abundance and growth. 3. Measurements of basal ecosystem responses collectively indicated increased en-ergy mobilization at the base of the food web in response to labile DOC addition. Periphyton bacterial production in the treatment reach was generally >1.5× refer-ence reach values, and periphyton ash-free dry mass, chlorophyll-a, and chloro-phyll-a:ash-free dry mass were all greater in the treatment reach by the end of the study. Throughout dosing, ecosystem respiration was 1.3× greater in the treat-ment reach and dissolved inorganic nitrogen uptake was greater in the treatment reach on eight out of nine measurements. 4. Benthic invertebrate counts, dominated by Baetis spp. and Chironomidae, were c. 4× greater after 28 dosing days and c. 8× greater after 56 days in the upstream portion of the treatment reach. Abundance generally declined with increasing dis-tance from the dosing station. Dolly Varden fry and parr age classes were nearly 2× more abundant in the upstream portion of the treatment reach than in any section of the reference reach and also declined with increasing distance from the dosing station. Further, Dolly Varden tagged with passive integrated transponders prior to the experiment had significantly higher instantaneous growth rates in the treatment reach than those recaptured in the reference reach. 5. The strong consumer responses to small quantities of labile DOC mirrored sig-nificant treatment reach increases in basal ecosystem function and therefore demonstrated a response consistent with a trophic upsurge. Terrestrial DOC has historically been viewed as contributing little to metazoan consumers, instead modulating the influence of nutrients and being respired out of a disconnected microbial loop. Because we dosed the treatment reach with a relevant concentra-tion of labile DOC, based on measurements in nearby peatland-draining streams, we suggest that terrestrial DOC deserves more attention as a basal resource for whole food webs, akin to nutrients fuelling green (autochthonous) pathways.Alaska Sustainable Salmon Fund, Grant/Award Number: 4470

City of Hitchcock Comprehensive Plan 2020-2040

Hitchcock is a small town located in Galveston County (Figure 1.1), nestled up on the Texas Gulf Coast. It lies about 40 miles south-east of Houston. The boundaries of the city encloses an area of land of 60.46 sq. miles, an area of water of 31.64 sq. miles at an elevation just 16 feet above sea level. Hitchcock has more undeveloped land (~90% of total area) than the county combined. Its strategic location gives it a driving force of opportunities in the Houston-Galveston Region.The guiding principles for this planning process were Hitchcock’s vision statement and its corresponding goals, which were crafted by the task force. The goals focus on factors of growth and development including public participation, development considerations, transportation, community facilities, economic development, parks, and housing and social vulnerabilityTexas Target Communitie

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Stitching the Strip: 7 Visions for the Future of Southeast Coralville

The Strip in Coralville is iconic of mid-century American strip retail development. Highway 6, also known as 2nd Street, is a 5-lane arterial street with the highest volume of traffic in the metro area. Buildings are located far from the street edge, and the vast majority of the area is covered with paved parking lots. While 2nd Street’s sidewalks are adequately wide and established street trees provide shade and enclosure, there are few crosswalks, creating unsafe conditions for pedestrians crossing the street. The Southeast Commercial District, located at the intersection of 2nd Street and 1st Avenue, is comprised of multi-family residential housing, retail, commercial, and industrial uses. Many of the buildings are functionally obsolete and some parcels exhibit evidence of neglect. Creative planning and design proposals envision alternative futures for the district, but existing conditions present several significant challenges. Towering electrical transmission lines bisect the district, some parcels are known to be contaminated and others potentially contaminated, and all new inhabited structures must be elevated above the FEMA 100-year flood plain to be insurable. At the same time, some conditions present opportunities: The Clear Creek and Iowa River waterfronts are underutilized and two rail lines with public transit potential bookend the district, and with any urban design proposal, there are opportunities for creating a sense of identify and place. Stitching The Strip: 7 Visions for the Future of Southeast Coralville presents urban design ideas for the Southeast Commercial District in Coralville, Iowa. Twenty-three mid-level landscape architecture graduate students enrolled in an intensive 8-week Community Planning and Design studio completed the work during the summer of 2018. The studio was co-led by Associate Professor Blake Belanger and Associate Professor Howard Hahn. The effort was supported with funding from Kansas State University’s Technical Assistance to Brownfields (TAB), and would not have been possible without support and engagement from Maggie Egbarts, TAB Services Coordinator (EPA Regions 5 and 7). We are also grateful for the support and guidance from Dan Holderness, Coralville City Engineer and Scott Larson, Coralville Assistant City Engineer, as well as our visiting design critic Associate Professor Carl Smith who delivered both exceptional insights and humor. The idea for the collaboration emerged from discussions at the 2017 National Brownfields Training Conference in Pittsburgh. Goals of the collaborative service-learning studio included providing students with first-hand experience working with a community, generating creative ideas for advancing the dialogue about planning the future of southeast Coralville, engaging residents and stakeholders and responding to their input, and supporting the mission of the project partners. The studio’s process included rigorous mapping of various conditions, a community planning workshop, design development through an iterative process, a final presentation to project partners and the Coralville Community Advisory Panel, and a public open house exhibiting posters of student proposals. In Chapter 1, we introduce Coralville’s Southeast Commercial District and present eight influential site and contextual factors identified in our research. We detail the studio’s methods and process, and introduce the seven student design proposals. In the following seven chapters, we present specific urban design strategies for establishing a new mixed-use district. In contrast to a singular master plan, the collection of ideas presented in Stitching The Strip provides a multitude of ideas that can be compared, evaluated, prioritized, and perhaps hybridized. We aspire that Stitching The Strip will contribute to the ongoing dialogue about the future of the Southeast Commercial District, and serve as an enduring legacy project for Coralville

City of Hitchcock Comprehensive Plan 2020-2040

Hitchcock is a small town located in Galveston County (Figure 1.1), nestled up on the Texas Gulf Coast. It lies about 40 miles south-east of Houston. The boundaries of the city encloses an area of land of 60.46 sq. miles, an area of water of 31.64 sq. miles at an elevation just 16 feet above sea level. Hitchcock has more undeveloped land (~90% of total area) than the county combined. Its strategic location gives it a driving force of opportunities in the Houston-Galveston Region.The guiding principles for this planning process were Hitchcock’s vision statement and its corresponding goals, which were crafted by the task force. The goals focus on factors of growth and development including public participation, development considerations, transportation, community facilities, economic development, parks, and housing and social vulnerabilityTexas Target Communitie