We evaluated the relative importance of "bottom-up" (production-limited) and "top-down" (predator-mediated) processes during early marine residence in a population of Chinook salmon (Oncorhynchus tshawytscha) from the upper Columbia River, USA. We examined length, mass, and condition index of age-0 juveniles collected in the ocean during June and September across 11...
Small rivers, such as those that line the Oregon coast, have been shown to deliver significant concentrations of suspended sediments and nutrients to estuaries and the coastal ocean during wet seasons during which winds are predominantly downwelling-favorable. The fate of the buoyant source water and of any suspended or dissolved...
Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean...
Biogeochemical reactions associated with stream nitrogen cycling, such as
nitrification and denitrification, can be strongly controlled by water and solute residence
times in the hyporheic zone (HZ). We used a whole‐stream steady state ¹⁵N‐labeled
nitrate (¹⁵NO₃⁻) and conservative tracer (Cl⁻) addition to investigate the spatial and
temporal physiochemical conditions controlling...
We measured the hyporheic residence time distribution in a 2nd-order mountain stream at the H. J. Andrews Experimental Forest, Oregon, and found it to be a power-law over at least 1.5 orders of magnitude in time (1.5 hr to 3.5 d). The residence time distribution has a very long tail...
Surface and subsurface flow dynamics govern residence time or water age until discharge, which is a key metric of storage and water availability for human use and ecosystem function. Although observations in small catchments have shown a fractal distribution of ages, residence times are difficult to directly quantify or measure...
Interest has increased in developing renewable energy sources to reduce U. S. dependence on oil. Policy makers and resource managers now are considering power generation technologies proposed for development along the Continental Shelf of the U. S. Pacific coast beyond state waters. This region supports abundant populations of seabirds and...
Development of wave and offshore wind-based marine renewable energy is anticipated on the Outer Continental Shelf (OCS) off Oregon and much of the Pacific Northwest in the coming decade. Multiple issues related to environmental considerations and information needs remain for these emerging industries. The Oregon Marine Renewable Energy Environmental Science...
A stable-isotope stratigraphy at Site 846 (tropical Pacific, 3°06'S, 90°49'W, 3307 m water depth), based on the benthic
foraminifers Cibicides wuellerstorfi and Uvigerina peregrina, yields a high-resolution record of deep-sea δ¹⁸O and δ¹³C over the
past 1.8 Ma, with an average sampling interval of 3 k.y. Variance in the δ¹⁸O...
Early ocean residence is considered a critical period for juvenile salmon although specific survival mechanisms are often unidentified and may vary by species or life stage. Columbia River spring-run Chinook salmon Oncorhynchus tshawytscha abundance has declined dramatically since the early 1900s. To elucidate mechanisms of early marine survival, we tested...