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Author: Robert A. Scherer
Publisher:
ISBN:
Category : Rivers
Languages : en
Pages : 254
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Book Description
High intensity sampling was undertaken to characterize the temporal and spatial variability of oxidized nitrogen (NO3-N + NO2-N), ammonia-nitrogen (NH3-N), total dissolved phosphorus, total unfiltered phosphorus and orthophosphorus (PO4-P) from two adjacent small streams in Western Oregon's Coast Range, Deer Creek (303 ha) and Flynn Creek (203 ha). Deer Creek has been 39 % clearcut from 1966 to 1987 while, Flynn Creek has never been logged and remains a "control" watershed for various research projects. A sequential wet-deposition precipitation sampler was also used to determine the temporal variability of oxidized-nitrogen, ammonia-nitrogen, total dissolved phosphorus and orthophosphorus entering a watershed during two storm events. Samples collected every one hour over a 25 to 26-h period during summer low flows indicated that oxidized nitrogen, ammonia-nitrogen, total unfiltered phosphorus, and orthophosphorus remained relatively constant. Total dissolved phosphorus concentrations were the most variable but did not have a discernible diel pattern. On a spatial scale, total unfiltered phosphorus and total dissolved phosphorus remained relatively constant or showed no discernable patterns when sampled over five 250-m intervals on each creek during summer low flow. Oxidized nitrogen and orthophosphorus concentrations increased on Deer Creek and decreased on Flynn Creek in an downstream direction. Ammonia-nitrogen concentrations decreased in a downstream direction on Deer Creek and remained constant on Flynn Creek. Nutrient constituent concentrations observed during high intensity sampling of three storm events had a variable response with stream discharge. Oxidized nitrogen concentration levels collected during the first fall storm appeared to be consistent with other research that has shown a flush of oxidized nitrogen out of the forest soil profile during the first fall storm. Sample concentrations from the first sampled storm had a 36 % decrease in concentration with the falling limb of the first sampled storm on both Deer Creek and Flynn Creek. Whereas, oxidized nitrogen concentrations had a 9 to 25 % decrease with an increase in discharge on the two studied creeks and returned to pre-storm levels with a decrease in discharge during two winter storms. Total unfiltered phosphorus concentrations had a 90 to 1150 % (0 to 10 fold) increase with a rise in storm discharge and decreased with the fall in storm discharge depending on the storm event and creek sampled. Ammonia-nitrogen, total dissolved phosphorus and orthophosphorus concentrations were not related to changes in discharge. Precipitation concentrations of oxidized nitrogen and ammonia-nitrogen either had a variable response or became diluted with an increase in rainfall amounts. The different responses appear to be related to storm intensity, with greater dilution in higher intensity storms. Results from this study indicate that the input and output of nitrogen and phosphorus into forested streams can be quite variable on both small temporal and spatial scales depending on the particular nutrient sampled, the particular creek sampled, stream flow conditions and season. It appears that sampling schemes designed for monitoring water chemistry or nutrient flux should initially presume significant short interval (2 to 20-h) variation until intensive sampling is able to prove otherwise.
Author: Robert A. Scherer
Publisher:
ISBN:
Category : Rivers
Languages : en
Pages : 254
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Book Description
High intensity sampling was undertaken to characterize the temporal and spatial variability of oxidized nitrogen (NO3-N + NO2-N), ammonia-nitrogen (NH3-N), total dissolved phosphorus, total unfiltered phosphorus and orthophosphorus (PO4-P) from two adjacent small streams in Western Oregon's Coast Range, Deer Creek (303 ha) and Flynn Creek (203 ha). Deer Creek has been 39 % clearcut from 1966 to 1987 while, Flynn Creek has never been logged and remains a "control" watershed for various research projects. A sequential wet-deposition precipitation sampler was also used to determine the temporal variability of oxidized-nitrogen, ammonia-nitrogen, total dissolved phosphorus and orthophosphorus entering a watershed during two storm events. Samples collected every one hour over a 25 to 26-h period during summer low flows indicated that oxidized nitrogen, ammonia-nitrogen, total unfiltered phosphorus, and orthophosphorus remained relatively constant. Total dissolved phosphorus concentrations were the most variable but did not have a discernible diel pattern. On a spatial scale, total unfiltered phosphorus and total dissolved phosphorus remained relatively constant or showed no discernable patterns when sampled over five 250-m intervals on each creek during summer low flow. Oxidized nitrogen and orthophosphorus concentrations increased on Deer Creek and decreased on Flynn Creek in an downstream direction. Ammonia-nitrogen concentrations decreased in a downstream direction on Deer Creek and remained constant on Flynn Creek. Nutrient constituent concentrations observed during high intensity sampling of three storm events had a variable response with stream discharge. Oxidized nitrogen concentration levels collected during the first fall storm appeared to be consistent with other research that has shown a flush of oxidized nitrogen out of the forest soil profile during the first fall storm. Sample concentrations from the first sampled storm had a 36 % decrease in concentration with the falling limb of the first sampled storm on both Deer Creek and Flynn Creek. Whereas, oxidized nitrogen concentrations had a 9 to 25 % decrease with an increase in discharge on the two studied creeks and returned to pre-storm levels with a decrease in discharge during two winter storms. Total unfiltered phosphorus concentrations had a 90 to 1150 % (0 to 10 fold) increase with a rise in storm discharge and decreased with the fall in storm discharge depending on the storm event and creek sampled. Ammonia-nitrogen, total dissolved phosphorus and orthophosphorus concentrations were not related to changes in discharge. Precipitation concentrations of oxidized nitrogen and ammonia-nitrogen either had a variable response or became diluted with an increase in rainfall amounts. The different responses appear to be related to storm intensity, with greater dilution in higher intensity storms. Results from this study indicate that the input and output of nitrogen and phosphorus into forested streams can be quite variable on both small temporal and spatial scales depending on the particular nutrient sampled, the particular creek sampled, stream flow conditions and season. It appears that sampling schemes designed for monitoring water chemistry or nutrient flux should initially presume significant short interval (2 to 20-h) variation until intensive sampling is able to prove otherwise.
Author: Paul D. Bakke
Publisher:
ISBN:
Category : Bull Run River Watershed (Or.)
Languages : en
Pages : 460
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An 18-year record of nitrate (NO3), orthophosphate, total nitrogen and total phosphorus in four streams of the Bull Run watershed, Oregon, was examined to determine its precision and time resolution. Of these four species, only NO3 was found to be known to a sufficient level of detail for modeling and inference purposes. The precision of precipitation NO3 and total nitrogen measurements at the Bull Run was found to be inadequately determined and much poorer than the precision of corresponding stream chemistry data. An autoregressive time-series multiple-regression model was developed to predict stream NO3 load (kg/ha/day) based on 14-day cumulative stream discharge, the current day's, previous day's and cumulative 7-day precipitation, the 14-day average maximum air temperature and a storm hysteresis factor. Coefficients of determination ranged from 0.66 to 0.75. The model was found to be of limited use in inference about watershed processes due to the coarse time resolution of the data (1 to 3 week sampling intervals). Although the 47 independent variables considered were known at much finer time scales (30 minutes to 1 day), this was insufficient to offset the problem of long sampling intervals and strengthen the inference capability. Complete description of the nutrient record would require sampling intervals of less than one day during periods of rapid change. Peak NO3 concentration and load events were found to be unrelated to suspended sediment concentration or the magnitude of snow melt. Stream NO3 showed a weak inverse relationship with precipitation NO3 or total nitrogen content. Where light and other non-nutrient factors are present in abundance, streams of the Bull Run watershed were found to be predominantly phosphorus limited, although nitrogen-limited conditions occur in 1 to 37 percent of the days sampled, depending on sub-basin.
Author: Frank A. Rinella
Publisher:
ISBN:
Category : Organic water pollutants
Languages : en
Pages : 76
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Author: V. Cody Hale
Publisher:
ISBN:
Category : Forest management
Languages : en
Pages : 220
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Book Description
Few studies have examined both long-term and fine-scale spatial variations in water quality of small streams in the Pacific Northwest. As such, a case study was conducted to determine if current physical and chemical properties of water in three streams located in the Oregon Coast Range differed from historically measured conditions, taking differences in past management regimes into account. In addition, this research provides an assessment of spatial and temporal variability in nitratenitrogen (N) concentrations and summer stream temperatures within each catchment. The three research catchments were part of the Alsea Watershed Study (1959- 1973), where effects of forest management practices were examined using a pairedwatershed study design. One catchment, Needle Branch, was clear-cut with no protection provided to the stream. Harvesting in Needle Branch was followed by an intense broadcast burn to remove logging slash. Another catchment, Deer Creek, was patch-cut in three small units resulting in a 25% harvest of the total catchment area, but buffers were retained along fish-bearing streams. The third catchment, Flynn Creek, was used as a control. In this revisit to the Alsea Watersheds, measurements were conducted continuously (discharge, turbidity), intermittently (suspended sediments), and at regular intervals (nitrate-N) for one year between October 2005 and September 2006. Summertime stream temperature was also measured every half-hour from mid-June to mid-September. Comparisons of recent data with historic data show no detectable changes over time for streamflow characteristics (annual runoff volume, peak flow discharges, and number of low-flow days), annual sediment yield, or summer maximum stream temperatures. Current nitrate-N export was similar to historically measured values for Flynn Creek and Deer Creek; however, export at Needle Branch was increased over past levels. This observation may be caused by dense colonization of the riparian area with red alder (Alnus rubra), a N-fixing species, following the 1966 harvest. Patterns of nitrate-N concentration varied throughout each catchment and are likely influenced by the current distribution of red alder stands. Synoptically measured stream temperatures were variable along each stream's longitudinal profile. The ability to meet Oregon's water quality standard for temperature was dependent on measurement location and method of analysis. Evaluating individual sampling points as discrete records resulted in each stream exceeding the standard for at least one measurement location, whereas evaluating the criteria based on the mean of all data collected within the mainstem stream excluded Flynn Creek and Needle Branch from violation. These results highlight the physical and chemical variability of stream water draining Oregon Coast Range headwater catchments and provide insight as to where future work should be focused to gain a more thorough understanding of these dynamic systems.
Author: Rebecca L. Flitcroft
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 378
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Aquatic ecological investigation is expanding to encompass considerations of multiple scales across large landscapes. Much of the analysis included in this work focuses specifically on coho salmon (Oncorhynchus kisutch) in multiple subbasins on the Oregon coast. Coho salmon were chosen for an investigation of spatial scales, network connections, and life history stages due to their broad distribution on the Oregon coast, and abundant data describing their distribution, habitat needs, behavior, and survival. Chapter 2 introduces dynamic network topology (DNT) as a framework for analysis and interpretation of aquatic obligate species. DNT is based on the premise that in-stream habitats change in form and organization over time, and native aquatic species are adapted to those changes through movement and life history diversity. Chapter 3 analyzes juvenile coho salmon density and stream network occupancy at three spatial scales (site, patch, and subbasin). The site scale analysis indicated that combining network and traditional in-stream habitat metrics (i.e., substrate and habitat juxtaposition variables) are most effective at describing juvenile coho salmon density. Patch sizes of juvenile coho salmon were defined using variograms. Variogram shape indicated that a nested spatial structure may be present in larger subbasins, indicating overlapping patterns of juvenile stream use. At the subbasin scale, stream network occupancy by juvenile coho salmon was shown to vary over time within subbasins, and appeared to increase or decrease similarly to the size of the adult spawning run. In chapter 3, two-tier Bayesian hierarchical models were applied to adult (subbasin and basin scales) and juvenile (site and subbasin scales) coho salmon in an attempt to combine spatial scales that might be influential at each life history stage. The best fitting adult model included the percent of large trees in the riparian zone at the subbasin scale with mean annual precipitation at the basin scale. The best fitting juvenile model included three variables, percent sand, stream order, and network distance to spawning habitat which mirrors the result of modeling efforts in Chapter 3. Multiple spatial scales and the framework of a stream network were informative at detecting patterns and interactions among scales and life history stages of coho salmon.
Author:
Publisher:
ISBN:
Category : Eutrophication
Languages : en
Pages : 258
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Author: Gary Lamberti
Publisher: Academic Press
ISBN: 0128132698
Category : Science
Languages : en
Pages : 374
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Book Description
Methods in Stream Ecology: Volume 2: Ecosystem Structure, Third Edition, provides a complete series of field and laboratory protocols in stream ecology that are ideal for teaching or conducting research. This new two-part edition is updated to reflect recent advances in the technology associated with ecological assessment of streams, including remote sensing. Volume two covers community interactions, ecosystem processes and ecosystem quality. With a student-friendly price, this new edition is key for all students and researchers in stream and freshwater ecology, freshwater biology, marine ecology and river ecology. This book is also supportive as a supplementary text for courses in watershed ecology/science, hydrology, fluvial geomorphology and landscape ecology. Methods in Stream Ecology, 3rd Edition, Volume 1: Ecosystem Structure, is also available now! Provides a variety of exercises in each chapter Includes detailed instructions, illustrations, formulae and data sheets for in-field research for students Presents taxonomic keys to common stream invertebrates and algae Includes website with tables and a links written by leading experts in stream ecology
Author: Matthew J. Kaylor
Publisher:
ISBN:
Category : Fish culture
Languages : en
Pages : 0
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Humans have drastically altered the physical habitat and food web structure of stream ecosystems. Two major impacts humans have had on Pacific Northwest streams are modification of streamside forests (as a result of agriculture, land development, and timber harvest), and declines in the return of wild anadromous salmon to headwater ecosystems (due to a range of habitat degradation, dams, harvest, and hatcheries). Riparian forest impacts have altered stream light dynamics, while the loss of salmon has led to declines in the delivery of nutrients from the ocean to streams. While the initial impacts of the modifications took place decades or even centuries ago, they can have lasting effects on stream ecosystems and food webs. This dissertation evaluates 1) influences of long-term recovery from historic riparian harvesting on stream light, habitat, and food webs, and 2) how reduced salmon subsidies to streams may be impacting stream productivity and food webs. Today most streams in the Pacific Northwest, and indeed across much of North America, have buffers of riparian forests that are regenerating from earlier land clearing. As stands recover, the trajectories of stand development will affect forest structure, which in turn affects stream light regimes. In the first half of my dissertation, I explore how stand age and structure relates to stream light availability and then how spatial differences and temporal changes in stream light influence stream food webs and higher trophic level biomass in headwater streams. In Chapter 2, I explore how stream light availability differs with the age and stage of riparian forests. I found that stream light flux was generally lower and less variable when bordered by second-growth forests compared to old-growth forests within a stream network and more broadly across forests west of the Cascade Mountains. Numerous studies have evaluated how large differences in light availability (e.g. fully forested compared to complete removal of riparian forests) influence stream food webs, but smaller differences in light availability, such as those found in Chapter 2, have received less consideration. In Chapter 3, I conducted surveys across 18 stream reaches and evaluated how variables associated with stream habitat, light, primary production, and macroinvertebrate biomass account for variability in the biomass of cutthroat trout and total vertebrates (fish and salamanders). Habitat metrics were not well correlated with higher trophic level biomass. In contrast, factors associated with resource availability -- as regulated through bottom-up, autotrophic pathways -- were closely related to the biomass of fish and other consumers. In Chapter 4, I quantified long-term responses of stream biota to the regeneration of riparian forests following clear-cut harvest. I resampled five stream reach pairs that were originally sampled in 1976 shortly after canopy removal. This initial survey showed that periphyton chlorophyll a, predatory invertebrate biomass, and cutthroat trout (Oncorhynchus clarkii clarkii) biomass were elevated in harvested reaches relative to reference reaches. After four decades of riparian regeneration, mean canopy openness, chlorophyll a, predatory invertebrate biomass, and cutthroat trout biomass declined in harvested reaches relative to paired old-growth reference reaches. Changes in canopy cover were consistent with biotic responses and suggest that changes in light availability as stands regenerated exerted control on biota through bottom-up pathways in these streams. While spatial and temporal light dynamics appear as important regulators of stream food webs in small forested streams of western Oregon, other factors may emerge as important constraints on food web productivity across stream networks in other regions. In the second half of my dissertation, I explore bottom-up drivers of fish production in a river network in eastern Oregon where canopies are more open than small western Oregon streams. I focus on nutrient and carbon subsides in this study as the loss of returning anadromous fish has been hypothesized as a key factor contributing to poor recovery of ESA-listed salmonids. In chapter 5, I evaluate network-scale spatial patterns of primary production, potential drivers of primary production, and juvenile salmonid abundance throughout two NE Oregon sub-basins. Primary production rates increased with watershed area and we were able to explain 72% of the variation in primary production across these basins using a combination of fixed-effects (e.g. light, nutrients, and temperature) and spatial autocorrelation. In contrast to other studies, juvenile salmonid abundance was greatest in cool headwaters where nutrient concentrations and rates of primary production were very low. To test the hypothesis that growth of juvenile salmonids and other biota in these low-productivity stream sections may be inhibited by the reduction of returning adult salmon and the associated loss of nutrient subsidies, I conducted a carcasses addition experiment in three locations of the Upper Grand Ronde River. In chapter 6, I focused on the responses of juvenile Chinook (Oncorhynchus tshawytsca) and steelhead (O. mykiss). Chinook and steelhead consumed an abundance of eggs and carcass tissue which resulted in greater growth rates and body condition of fish in treatment reaches relative to controls. To contextualize potential effects of increased growth on Chinook survival, I used an 18 year tagging and detection dataset to evaluate Chinook length-survival relationships. The positive association between length and survival suggests that actions resulting in larger Chinook lead to increased survival rates. In chapter 7, I evaluate carcass addition effects on the broader food web. Periphyton, aquatic invertebrates, and non-salmonid fish assimilated carcass nitrogen, but enrichment was far less than observed in juvenile salmonids. In contrast to salmonids, diet analysis and stable isotope patterns indicated that non-salmonids were not consuming eggs and carcass material, suggesting carcass nitrogen assimilation occurred through bottom-up pathways. These results suggest that salmon subsidies have the potential to broadly impact stream food webs in this region, but that species able to directly consume eggs and carcass material (i.e. juvenile salmonids) clearly benefit more from these subsidies.
Author:
Publisher:
ISBN:
Category : Hydrology
Languages : en
Pages : 962
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Author: Erin Kathleen Mick
Publisher:
ISBN:
Category : Phosphorus
Languages : en
Pages : 194
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