Amnesic shellfish poisoning is the result of eating seafood contaminated with domoic acid, produced by toxigenic diatom species from the genus Pseudo-nitzschia. In the summer of 2015, abnormally large assemblies, known as super chains, of Pseudo-nitzschia australis appeared in the massive algal bloom that swept up the Pacific Coast. This affected commercial and recreational shellfish harvesting and cost millions of dollars in shellfish sales. Due to their recent appearance, knowledge of P. australis super chains is extremely limited. Here, we investigate the prevalence of super chains in Puget Sound and along the Pacific Coast. The deep chlorophyll maximum, DCM, is a layer in the water column that is often found to contain a high volume of photosynthesizing phytoplankton.  A collection of electronic devices that measure conductivity, temperature, and depth (also called CTD) was deployed to determine DCM, from which plankton samples were collected. Scanning electron and light microscopy were used to identify P. australis species and to examine the morphology of their associated bacteria. Most surveys have been conducted during the late summer when blooms are at their peak. By conducting our survey in the late winter, we have had the opportunity to measure P. australis super chain prevalence during what is typically a less active season. Our results provide novel information of P. australis super chains and their associated bacteria during a season that has been so far neglected. In addition, our diverse sample sites in Puget Sound and along the West Coast present a systematic survey and allow us to make regional comparisons. This study lays a foundation for more comprehensive research of super chains in the future. 

Glacial erratics are rocks that have been transported and deposited by glaciers. They are typically characterized by large size and a composition that differs from the surrounding geologic features, indicating a foreign source. Determining the source of these erratics provides evidence of ice flow direction, which helps to reconstruct glacial history of a region. Our project focuses on a glacial erratic located in West Seattle at the entrance to the South Seattle College campus. Our research has two main goals. Our first goal is to determine the composition of the glacial erratic through mineral property tests and optical analysis, and use this information to identify potential origins of the rock. Our second goal is to determine if the characteristics of the sediment underlying the erratic are consistent with recent glacial transport. Using sediment samples and existing borehole data, we have constructed subsurface cross-sections showing the stratigraphy of underlying deposits. Preliminary mineralogical and composition analyses indicate that this rock is not native to the Puget Sound basin, and may have been transported from as far away as the northern San Juan Islands or Canadian Cascades. Analysis of existing borehole data and sediment sampling indicate the underlying stratigraphy includes glacial till and outwash deposits consistent with our hypothesis that the erratic was deposited during one of the recent glacial pulses. Learning more about the glacial erratics in the Puget Sound area can help confirm the path and timeline of ice sheets that covered the area thousands of years ago.

Students of Everett Community College’s Ocean College Research Academy (ORCA) analyzed pH trends in the Snohomish River estuary of Possession Sound using ten years of data. Influences on water chemistry include freshwater discharge from the Snohomish River and tidal currents in Possession Sound. In addition, high salinity, cold water from the Pacific Ocean may transport low pH water as a result of ocean acidification, when atmospheric carbon dioxide dissolves in seawater and decreases the pH. Students wanted to investigate whether average pH in Possession Sound had been decreasing over time. Data were analyzed during the winter months, November through March, from 2006 to 2016. We collected data from October 2015 through May 2016, with archived data collected by previous ORCA students. Water chemistry at three sample sites in the Possession Sound were compared. Recordings of pH from the surface to five meters were completed with a YSI 650 and averaged. The most significant decreases in pH occurred at locations in closer proximity to the shore, near south Whidbey Island and Mukilteo. Each had an overall decrease of 0.3, compared to only 0.1 in the middle of the sound near Hat Island. Decreased pH in an estuary system directly affects the development of many organisms, such as phytoplankton, which make up the primary levels of the trophic pyramid. Further investigation is ongoing about the effects of salinity and river discharge on these minimal decreases in pH, along with seasonal fluctuations in primary production by phytoplankton as well as the effects of decreased pH on phytoplankton.

At the Snohomish River estuary, seafloor sediment composition correlates with river discharge. With an increase in river discharge mixing of sediments occurs and the heavy metal particles become suspended in the water column. With a decrease in river discharge sediment concentrations deposit on the sea floor. Ocean Research College Academy (ORCA) students, including ourselves, collected the data used in this investigation on monthly research cruises throughout 2015. We hypothesized that in 2015, higher levels of Snohomish River discharge would lead to lower concentrations of heavy metals in the sediment. River discharge data from the Snohomish River was collected three days prior to the date of sediment collection. Arsenic, copper, and lead concentrations were sampled from three sites in Possession Sound: Mount Baker Terminal (MBT), a buoy southwest of the jetty, and the delta. The results showed that heavy metal concentration decreased with increasing river discharge, with the exception of one site. At MBT, south of the Snohomish River, all of the heavy metal concentrations declined with the increase of river discharge. A rise in river discharge of 1,980 to 25,400ft^3/sec caused a decrease in arsenic from 4.84 to 2.49mg/kg, copper from 15.2 to 8.53, and lead from 7.17 to 2.81mg/kg. The site at the river delta followed the same trend, with a range in river discharge of 1,980 to 10,400ft^3/sec correlating with a decrease in arsenic from 9.34 to 6.06mg/kg, copper from 20.5 to 13.4mg/kg, and lead from 5.94 to 3.04mg/kg. The exception was Buoy, located to the southwest of the jetty. With an increase in river discharge from 3,910 to 29,300ft^3/sec, arsenic rose from 5.74 to 7.14mg/kg, copper from 15.4 to 21.5mg/kg, and lead from 4.31 to 5.78mg/kg. Heavy metal concentrations have been found to be harmful to marine organisms in high concentrations. Thus for further research we will be collecting data on heavy metal concentrations found in local plankton populations, in order to find a correlation between the two.