Ashley Coble

Ashley Coble
National Council for Air and Stream Improvement, Corvallis, Oregon

PhD

About

37
Publications
6,294
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
420
Citations
Additional affiliations
June 2008 - July 2010
Northern Arizona University
Position
  • Research Assistant

Publications

Publications (37)
Article
Considering recent increases in anthropogenic N loading it is essential to identify the controls on N removal and retention in aquatic ecosystems because the fate of N has consequences for water quality in streams and downstream ecosystems. Biological uptake of nitrate (NO3-) is a major pathway by which N is removed from these ecosystems. Here we u...
Article
Environmental DNA (eDNA) is an emerging biological monitoring tool that can aid in assessing the effects of forestry and forest manufacturing activities on biota. Monitoring taxa across broad spatial and temporal scales is necessary to ensure forest management and forest manufacturing activities meet their environmental goals of maintaining biodive...
Article
Full-text available
Many microbes responsible for inorganic nutrient uptake and transformation utilize dissolved organic matter (DOM) as a nutrient or energy source, but little is known about whether DOM composition is an important driver of nutrient uptake in streams. Our goal was to determine whether incorporating DOM composition metrics with other more commonly con...
Article
Full-text available
In the Anthropocene, watershed chemical transport is increasingly dominated by novel combinations of elements, which are hydrologically linked together as ‘chemical cocktails.’ Chemical cocktails are novel because human activities greatly enhance elemental concentrations and their probability for biogeochemical interactions and shared transport alo...
Article
Full-text available
Anthropogenic activities have increased solute concentrations and fluxes in rivers globally. Increases in salt, dissolved organic carbon, and inorganic nutrients have been attributed to changes in atmospheric deposition, road salt and fertilizer application, and urbanization. Extremely large flood events, which are increasing in frequency and durat...
Article
Full-text available
Glyphosate is the most commonly used herbicide globally, which has contributed to its ubiquitous presence in the environment. Glyphosate application rates and delivery to surface water vary with land use. Streams in urban and agricultural catchments can experience continuous delivery of low concentrations of glyphosate and aminomethylphosphonic aci...
Article
Full-text available
Dissolved organic carbon (DOC) and nitrogen (DON) are important energy and nutrient sources for aquatic ecosystems. In many northern temperate freshwater systems DOC has increased in the past 50 years. Less is known about how changes in DOC may vary across latitudes, and whether changes in DON track those of DOC. Here we present long‐term DOC and D...
Data
A global compilation of stream chemistry data was synthesized to evaluate spatial and temporal trends in solutes with a particular focus on dissolved organic matter and nitrogen (inorganic and organic forms). Data span a global array of streams and rivers ranging from the tropics to the arctic. Data include concentrations of dissolved organic nitro...
Article
Full-text available
A comprehensive cross‐biome assessment of major nitrogen (N) species that includes dissolved organic N (DON) is central to understanding interactions between inorganic nutrients and organic matter in running waters. Here, we synthesize stream water N chemistry across biomes and find that the composition of the dissolved N pool shifts from highly he...
Article
Full-text available
Increasing concentrations of dissolved organic carbon (DOC) have been identified in many freshwater systems over the last three decades. Studies have generally nominated atmospheric deposition as the key driver of this trend, with changes in climatic factors also contributing. However, there is still much uncertainty concerning net effects of these...
Article
1. Models of ecosystem development and response to environmental variation must incorporate change in vertical soil space as well as over time. Insufficient measurement of subsurface soil properties represents a major observational bias in ecosystem studies. 2.We address these changes in horizontal (time) and vertical (soil profile) space along a t...
Article
Full-text available
The Central Siberian Plateau is undergoing rapid climate change that has resulted in increased frequency of forest fires and subsequent alteration of watershed carbon and nutrient dynamics. Across a watershed chronosequence (3 to >100 years since wildfire) we quantified the effects of fire on quantity and composition of dissolved organic matter (DO...
Article
Full-text available
Understanding the drivers of variability in the concentration and composition of dissolved organic matter (DOM) in running waters is a fundamental challenge for aquatic biogeochemistry. Although multiple conceptual frameworks have been proposed to quantify expected changes in DOM within a river network, few studies have collected data to document t...
Article
Climate change may affect export of essential nutrients to downstream ecosystems in regions that host substantial winter snowpack, yet nutrient uptake is rarely quantified in snow- and ice-covered streams and rivers. To evaluate how nutrient uptake varied year-round in relation to commonly identified drivers of uptake (nutrient concentrations, biol...
Article
Biogeochemical theory and a substantial body of empirical data show that nitrogen (N), an atmospherically derived nutrient, limits plant growth on young substrates, while phosphorus (P), a rock-derived nutrient, limits plant growth on old substrates. In arid regions, water is also often a limiting resource to plant growth. We applied resource amend...
Article
Dissolved organic matter (DOM) composition may be an important determinant of its fate in freshwaters, but little is known about temporal variability in DOM composition and the biodegradability of DOM in northern temperate watersheds. We measured biodegradable dissolved organic carbon (BDOC) via incubation assays and DOM composition using optical i...
Article
Dissolved organic matter (DOM) plays an integral role in the biogeochemical cycles of aquatic ecosystems, and rates of DOM mineralization can be affected by nitrogen (N) and carbon (C) availability in the water column. To determine if DOM mineralization rates were limited by availability of N or C in a small tributary of Lake Superior, we conducted...
Article
Without exogenous rock-derived nutrient sources, terrestrial ecosystems may eventually regress or reach a terminal steady state, but the degree to which exogenous nutrient sources buffer or slow to a theoretical terminal steady state remains unclear. We used strontium isotope ratios (87Sr/86Sr) as a tracer and measured 87Sr/86Sr values in aeolian d...
Article
Historical copper-rich mining residue in the form of stamp sands were deposited widely along streams and lakes in the Western Upper Peninsula and are an important source of pollution affecting Lake Superior and its tributaries. The Hills Creek Stamp Sand Stabilization project has taken an innovative approach to stabilize and vegetate riparian aggra...
Article
We explored variables likely to affect health of Agassiz's desert tortoises (Gopherus agassizii) in a 1,183-km2 study area in the central Mojave Desert of California between 2005 and 2008. We evaluated 1,004 tortoises for prevalence and spatial distribution of 2 pathogens, Mycoplasma agassizii and M. testudineum, that cause upper respiratory tract...
Article
Seasonal and spatial variability in environmental factors may affect dissolved organic matter composition and nutrient transformation and retention in streams. The objective of this research was to quantify and describe seasonality, quantity, and quality of nutrient processing and export of ammonium (NH4), soluble reactive phosphate (SRP), and diss...
Article
In-stream biogeochemical uptake and transformation can alter the timing and form of nutrients exported to downstream ecosystems, but spatial and temporal nutrient contributions from small streams to large lakes have been generally ignored. We measured uptake of ammonium (NH4), soluble reactive phosphate (SRP), and dissolved organic carbon (DOC) in...
Article
Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential f...
Conference Paper
Background/Question/Methods An abundance of headwater streams along Lake Superior’s shores may comprise a major input of nutrients and account for nutrient sources that are currently unaccounted for in Lake Superior nutrient budgets. However, in-stream biogeochemical cycling can control how quickly nutrients are taken up or transformed, and conse...
Article
Background/Question/Methods An abundance of headwater streams along Lake Superior’s shores may comprise a major input of nutrients and account for nutrient sources that are currently unaccounted for in Lake Superior nutrient budgets. However, in-stream biogeochemical cycling can control how quickly nutrients are taken up or transformed, and consequ...
Article
In-stream biogeochemical cycling can control the timing and form of nutrients exported from watersheds to downstream ecosystems, and seasonal changes in light availability, discharge, temperature, or nutrient inputs may affect nutrient transformation and retention. Without an understanding of how in-stream biogeochemical cycling varies seasonally i...
Article
Full-text available
We examined ichthyoplankton sampled from 2 stations, 9 and 18 km offshore of Newport, Oregon, USA, over a decade of cruises every 2 wk from 1996 to 2005. The 10 most dominant taxa comprised approximately 87.3% of the total catch. Concentration of fish larvae was highest in January to March, whereas diversity peaked from March through May. Both over...

Network

Cited By