Browsing College of Engineering and Mines (CEM) by Subject "decomposition"
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The influence of decomposing salmon on water chemistryTo increase our knowledge of the biological and chemical effects of the decomposition of seafood material, we have initiated a study of the decomposition of salmon carcasses in a natural system in southeastern Alaska (i.e. Little Port Walter estuary). The Pacific salmon migrates through this estuary when returning to its natal stream to spawn. Following spawning the fish die and the carcasses are eventually carried to the estuary where they sink to the bottom. During periods of low stream flow, the dead carcasses may remain in the stream itself until higher stream flows transport them to the estuary. In years of large escapements, the density of fish in the spawning stream can be very high. In the system chosen for our work, spawning densities greater than six fish per m2 have been recorded although at the time the current study was conducted the spawning density was slightly more than two fish per m2. Since our system involves primarily pink salmon (O. gorbuscha), the average weight of the fish can be assumed to be 2-3 kilograms. Thus, our study is concerned with the fate and distribution of some 75 metric tons of organic matter in the form of salmon carcasses in one small estuary in Southeastern Alaska. We are particularly interested in determining: (1) the effects of the salmon carcass decomposition on the nitrogen chemistry of the water in which the decomposition occurs; (2) the form and distribution of the organic matter which is returned to the marine system; and (3) the rate at which remineralization occurs. This paper presents the results of our initial investigations.