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| 02706nam 2200385zi 4500 |
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| 001 | 9.878319 |
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| 003 | CaOODSP |
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| 005 | 20221107165216 |
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| 006 | m o d f |
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| 007 | cr ||||||||||| |
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| 008 | 190821s1993 oncbd #ob f000 0 eng d |
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| 040 | |aCaOODSP|beng|erda|cCaOODSP |
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| 043 | |an-cn-on |
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| 086 | 1 |aEn13-5/93-04E-PDF |
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| 100 | 1 |aReynoldson, Trefor B., |eauthor. |
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| 245 | 10|aHistoric changes in populations of burrowing mayflies (Hexagenia limbata) from Lake Erie based on sediment tusk profiles / |cTrefor B. Reynoldson and A.L. Hamilton. |
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| 264 | 1|aBurlington, Ontario : |bNational Water Research Institute ; |aOttawa, Ontario : |bInternational Joint Commission, |c[1993] |
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| 300 | |a1 online resource (21 pages, 4 unnumbered pages) : |bmaps, graphs. |
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| 336 | |atext|btxt|2rdacontent |
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| 337 | |acomputer|bc|2rdamedia |
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| 338 | |aonline resource|bcr|2rdacarrier |
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| 490 | 1 |a[NWRI contribution] ; |v[93-04] |
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| 500 | |aDigitized edition from print [produced by Environment and Climate Change Canada]. |
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| 504 | |aIncludes bibliographical references (pages 16-19). |
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| 520 | 3 |a"One of the most dramatic recorded changes in benthic invertebrate community structure due to eutrophication was the elimination of the burrowinq mayfly, Hexagenia limbata, from the western basin of Lake Erie. This was a catastrophic event occurring as a result of two periods of anoxia in the summers of 1953 and 1955. From the examination of sediment cores the changes in historic populations of Hexagenia have been reconstructed from enumeration of mandibular tusks. The changes in the numbers of tusks found in the sediment cores from the western basin of Lake Erie agree well with known historic events but suggest that numbers found in the earliest field samples represent a considerable increase over historic populations. Cores taken from the central basin suggest that Hexagenia was formerly only found in a band around the shore and populations never occurred in the offshore waters. It is suggested that this is strong evidence for the occurrence of brief periods of anoxia in the central basin of Lake Erie prior to cultural eutrophication"--Abstract, page 3. |
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| 692 | 07|2gccst|aSediments |
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| 692 | 07|2gccst|aLakes |
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| 692 | 07|2gccst|aHistorical research |
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| 700 | 1 |aHamilton, Andrew L. |q(Andrew Lloyd)|eauthor. |
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| 710 | 1 |aCanada. |bEnvironment Canada. |
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| 710 | 2 |aInternational Joint Commission. |
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| 710 | 2 |aNational Water Research Institute (Canada) |
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| 830 | #0|aNWRI contribution ;|v93-04.|w(CaOODSP)9.844121 |
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| 856 | 40|qPDF|s2.00 MB|uhttps://publications.gc.ca/collections/collection_2019/eccc/en13-5/En13-5-93-04-eng.pdf |
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