Investigating Fluctuations in Organic Matter Content Between Transects at Pacific Salmon Rearing Stream

Abstract

Pacific Salmon are some of the most influential keystone species in the coastal Pacific Northwest, crossing the barrier between ocean and land to deliver large amounts of marine-derived nutrients to terrestrial ecosystems after spawning and decomposing (Janetsk et al., 2009). This process enriches soil organic matter content by elevating levels of carbon, phosphorus, and nitrogen in the soils within proximity to salmon-bearing streams (Bilby et al., 2003). Evidence from previous studies suggests that the level of organic matter is higher near stream banks due to salmon decomposition, and decreases with distance away from this riparian region. However, there is a lack of literature investigating this phenomenon in urban streams. The fluctuation of salmon-derived organic matter was examined perpendicular to an urban salmon rearing stream in Cougar Creek, Delta, British Columbia. Samples were collected at increments of 5 metres, starting at the side of the stream and moving farther away into the forest. Using hydrogen peroxide as a reagent, the mass of organic content was measured at each transect. It was hypothesized that there would be a trend of decreasing organic soil content observed at samples farther away from the stream. While statistical analyses revealed that there was a significant difference between the means of organic matter at each transect (p = 0.0003), the experimental results did not demonstrate a decreasing trend in organic matter distribution at increasing distances perpendicular to the stream.