The source and fate of hazardous material released into rivers and estuaries is critically important to protecting environmental health, especially in highly industrialized areas such as the Puget Sound. This study focuses on determining the legacy of heavy metal distribution (Pb-Cu-Zn-As) from a demolished ASARCO smelter site in north Everett, WA near the mouth of the Snohomish River. The Snohomish is a complex riverine system with many potential point and non-point sources of contaminants. This site is the target of remedial actions under the Model Toxics Control Act cleanup regulation developed by the Washington Department of Ecology due to widespread As and Pb contamination in the early 1900’s. Previous studies showed a correlation between heavy metal concentrations in benthic sediment of Possession Sound and proximity to industrial sites near the mouth of the Snohomish River. If the source is the ASARCO smelter, we should be able to trace Pb contamination downstream from the site. No data are available from within the river to constrain the specific sources of anthropogenic metals. In our study, we use Pb isotope variability between natural and anthropogenic Pb to establish the extent of dispersion of contaminants derived from ASARCO. The sample suite we collected consists of: three one-meter-long river-bottom sediment cores collected 1) near the mouth of the Snohomish River, 2) near the ASARCO site, and 3) up river to compare natural baseline values with near site and downriver sites; and 4) slag samples to serve as reference isotopic signature of ASARCO Pb. Purification of Pb from the samples is complete, and the isotopic analyses of the Pb are in progress utilizing an inductively coupled plasma mass spectrometer under the advisory of Dr. Bruce Nelson at the University of Washington. This research will identify spatial and temporal relationships among fluvial processes and Pb deposition.

The Possession Sound, located within the Puget Sound, is a diverse estuarine environment where freshwater from the Snohomish River mixes with the ocean water from the Strait of Juan de Fuca. A key variable that influences fluctuations in an estuary system is tidal stage changes that result in mixing and stratification that influence water chemistry. The working hypothesis is that increased high salinity, cold water during high tide will result in decreased pH and increased dissolved oxygen (D.O.) Data from 2010 to 2013 were collected monthly at the Mukilteo and Mount Baker Terminal stations. YSI 85 and 650 data for salinity, temperature, pH, and D.O. were organized based on tidal stages. The data did not support our hypothesis; trend lines indicate that as tidal stages increase pH increases from 7.5 to 7.6. On average, D.O. decreased as tidal stages increased, from 9.1mg/L to 8.4 mg/L. Chemical levels in the water column are also influenced by phytoplankton through photosynthesis and respiration. Future research will be conducted to determine the correlation between the amount of plankton in the water and the levels of pH and D.O. in the water column.

Possession Sound and the Snohomish River Estuary system support a vast diversity of marine organisms and a complex biotic web sustained by nutrients introduced via upwelling and Snohomish River outflow. Over the past three years (2011-2013) the Ocean Research College Academy (ORCA) has gathered nutrient data on monthly State of Possession Sound (SOPS) cruises using a Niskin bottle and a YSI (a tool used to measure water chemistry). Our study explored trends in nutrient data in the surface and halocline of the Possession Sound water column over the course of a year as related to temperature and dissolved oxygen content. Water samples from our study were sent to the University of Washington Marine Chemistry Labs for nutrient analysis. We hypothesized that NOx (nitrite and nitrate) levels would be comparatively lower overall in the spring and summer than to fall and winter. Conversely, ammonium levels would be lower in the fall and winter and higher during the spring and summer. In the spring and summer months, more NOx would be utilized and therefore extracted from the system by photosynthesizing marine organisms, while in the fall and winter, decaying organic matter would release NOx without being depleted by marine organisms, allowing the NOx count to increase. With the increase in photosynthesis and marine organism counts during the spring and summer, defecation would increase, thus increasing ammonium levels. The data partially supported this hypothesis. NOx concentrations followed the predicted trends, however ammonium level variation correlated with factors beyond the original scope of the investigation. Future research will include exploration into seasonal chlorophyll levels providing evidence of phytoplankton activity, thus nutrient usage.

Possession Sound is located between the coastline of Snohomish county and Southeast of the Whidbey Island Basin within the Puget Sound. The freshwater Snohomish River is the second greatest input to the Puget Sound and greatly affects the overall health of Possession Sound. Monthly since 2009, the Ocean Research College Academy (ORCA) students collect samples in the Possession Sound with a Niskin bottle, to send to the University of Washington Marine Chemistry Lab which provides nutrient concentrations which can fluctuate with season, weather, river discharge, marine organisms, and anthropogenic influences, specifically waste water outfall. Focal analysis of a site close to the Snohomish River were compared to other locations up river. Discharge data corresponds with fluctuating levels of nitrates, nitrites (NOx) and ammonia throughout the year. NOx data corresponds with river discharge with an exception to spring where there is a general decrease. In April of 2013, for example, the discharge is at a high 18,300 ft³/second, but the NOx concentrations are at lows, at 3.04 μm/L. The subtle changes in ammonia concentrations seem to correlate with the extremes in river discharge. For example, between May and June of 2010, the river discharge data increases from 12,550 ft³/second to 15,090 ft³/second. Ammonia concentration follows, in May the concentration is 36.8 μm/L, which increases in June to 49.8 μm/L. The hypothesis was partially supported. Ammonia data correlated with river discharge, raising as river discharge flow increases. Comparatively, the NOx data varied independently of river discharge. Further research into ammonia concentrations and waste water outfall in addition to utilization of NOx by plankton species such as Thalassiosira spp. and Copepod spp. populations is yet to be conducted.

At the Ocean Research College Academy (ORCA), data is collected monthly at five locations in Possession Sound and is used to create a bigger picture of the health of the sound. Previous studies demonstrate that heavy metal concentrations in the sediment of Possession Sound and the Snohomish River vary with location. Upriver and point source anthropogenic influences contribute heavy metals, including zinc, lead and arsenic, to seafloor sediment and adversely affect the quality of the sediment. This study focused on bottom sediment at three different locations in Possession Sound and in the Snohomish River to investigate spatial patterns in heavy metal concentrations due to river influence. The sites, with increasing distance from the river, are three upriver samples, and three sites in Possession Sound. The river site sediment was potentially affected by the legacy of the ASARCO smelter in North Everett. Sites 1 and 2 are located near the mouth of the Snohomish River. Site 3 includes Mukilteo and Mount Baker Terminal data, both near busy ports and recreational areas. At these three sites, sediment samples were collected by utilizing a ponar grab. These samples were analyzed in the lab, and showed the heavy metal levels for each site. United States Geological Survey river flow data was also accessed to tie the high heavy metal patterns due to high river flow and greater discharge of sediments. Further research could be conducted to measure the biological impact that these metals have through bioaccumulation, based on our findings of heavy metal hot spots.

The Snohomish River flows through an area where anthropogenic factors may affect the water chemistry due to industry and agriculture. The lower reaches of the Snohomish River are near industrial sources. At the Ocean Research College Academy (ORCA) in Everett, Washington, students are encouraged to derive and conduct independent research studies in the Snohomish River estuary system on monthly State of Possession Sound (SOPS) research cruises. It is expected that data will change in relation to distance from anthropogenic influences and the mouth of the Snohomish River. The pH up river is expected to be, overall, lower than that of the salt water, and even lower with the influence of farm waste and factory runoff. The waste from these sources releases CO2 into the river causing the pH to decrease. Sampling sites for the data collection of this study were selected with consideration to farms and factories along the river. The data collected includes dissolved oxygen (D.O.), salinity, temperature, and pH. A handheld YSI 650 and YSI 85 were used. Nutrient samples were collected at approximately half a meter below the surface. From the data it can be determined how farms and other anthropogenic factors affect pH. Further research on how these factors affect the marine life in the Snohomish River estuary system and Possession Sound are planned for future studies to determine how changes in water chemistry may have a negative impact on estuarine ecosystems.
 

Theoretical descriptions of nature often depend on perturbative approaches that seldom extend beyond linearized approximations, and this translates to a large body of our understanding of physical systems ranging from cosmology, to nonequilibrium chemical processes, to aerospace control systems being only poorly understood. Our research focuses on the question of the extent to which computational simulations of nonlinear systems is experimentally verifiable. Here we use a quantitative measure of computational vs. experimental agreement called the horizon time and demonstrate its use through direct comparison of theoretical, computational and experimental modes of analysis using a damped, coupled physical pendulum apparatus, and specially developed data acquisition and analysis software. We find that a strong sensitivity of initial conditions, shown in the Lyapunov exponents, causes a rapid divergence between nearby trajectories within a tolerance range for experimentally observed motion which limits the horizon time to between 0.9 and 4.3 seconds before our trajectories can no longer be distinguished. By creating our own modified horizon time definition for use in a characteristic state space of known dimensions, we can only predict up to 1.3 seconds of motion before the trajectories cannot be distinguished. This small temporal resolution severely limits how effectively our theory can function as a description of experimental motion.