20 PPDQ Flashcards
what is the problem?
-Puget Sound in Washington state (USA) is home to some of the most heavily urbanized watersheds in the Pacific northwest
-washington’s population is approx, 8 million and is growing by about 100,000 people per year
what has this problem led to?
-over the 19th and 20th centuries, this has led to degradation (through straitening of creeks and installation of pipes and weirs) and pollution of many watersheds, and a general decrease in ecosystem quality
what was the result from what this problem has led to?
-as a result, man of these animals inhabiting these streams, including many iconic and culturally important salmon species, have disappeared
why are salmon important?
-salmon have been the cornerstone of the diet and traditional way of life of the Salish peoples for centuries
-their disappearance has been a tragic loss to these indigenous peoples who refer to themselves as “salmon people”
what is happening now for the problem?
-the relentless advocacy of indigenous groups and an increasing desire of urban settlers for outdoor recreation have led to a push for re-naturalization in many cities and suburbs
what has this advocacy made happen?
-removal or replacement of culverts and re-naturalization of previously straightened streams in the late 1990s and early 2000s were some of the measures that were applied
what did this re-naturalization show?
-the efforts showed success, and salmon began returning to these streams in greater and greater numbers-overall stock numbers (slowly) increased too
what was the mysterious phenomenon that happened to the salmon?
-a mysterious phenomenon was observed whenever it rained; coho salmon began gasping for oxygen, spiraling in the water and died rapidly thereafter
-this phenomenon was called Urban Runoff Mortality Syndrome (URMS)
-the causes for this phenomenon remained unknown for almost two decades
did they do tests to determine the cause?
scientists took samples and ran chemical analyses and other tests for all presently known causes of fish kills-nothing conclusive
-a search for the needle in the haystack ensued
what were the likely culprits?
the likely culprits could finally be narrowed down due to the advancement of chemical analytical technology in:
-throughput; how many samples can we measure?
-sensitivity; how low of a level can we detect?
-resolution; how many chemicals can we see at once?
what are high-resolution mass spectrometer?
have revolutionized the field of analytical chemistry
-they can measure ultra-low levels of thousands of chemicals at once, within minutes
-using these methods, roadway runoff and tire wear particles could finally be identified as the cause of URMS in coho salmon
how did a team at U of W set out to find the chemicals responsible for USMR in coho salmon?
-by sequentially splitting samples that caused URMS into “fractions” researchers narrowed it down to one fraction containing only four individual compounds
-in that fraction, they identified a chemical named 6PPD-quinone that is formed by the environmental reaction of the tire anti-degradant 6PPD with ozone and/or oxygen
how toxic is 6PPD-quinone?
kills half of the exposed coho at levels as low as 95ng/L
-for reference, in an olympic pool: ng/L=2 grains of sugar
what did his (the lecturer) and his team at USask research?
studied the sensitivity of four species of commercial, recreational and cultural important: rainbow trout, brook trout, arctic char and white sturgeon
which fish were sensitive?
rainbow trout and brook trout were sensitive at environmentally relevant levels, arctic char and white sturgeon were not
-rainbow trout were considerably slower to respond than brook trout and coho salmon
what does 6PPD-quinone affect?
-through a series of experiments, his team could show that it effects mitochondria (the cells power houses)
