caa a22 4500 469106387 CHVBK 20180323133057.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00044172 doi (NATIONALLICENCE)springer-10.1007/BF00044172 The ultrastructural indicators of aquatic ecosystem health [Elektronische Daten] [Gary Leppard, Mohiuddin Munawar] Analyses by transmission electron microscopy (TEM) of the smallest organisms in surface waters can be used to assess ecosystem health; the evidence for this statement is reviewed and recommendations are made for optimal use of TEM technology in providing such assessments. Those groups of small organisms currently being considered as indicators of ecosystem health (viruses, bacteria, autotrophic picoplankton, and autotrophic nanoplankton) are reviewed briefly as subjects for monitoring by TEM. New information on direct counting by TEM of viral femtoplankton indicates that viruses can be present in numbers 103 to 107 times greater than previously estimated by the traditional counts of plaque-forming units using various host bacteria. Such concentrations indicate that virus infections may exert ecological control over planktonic microbes. Ultrastructural research on prokaryotic picoplankton suggests that TEM analyses of cells in ultra-thin sections can be used to speciate the picoplankton and to diagnose them for cytological modifications related to environmental stress. Considering their great importance, episodically, to primary productivity and to modulating the speciation of higher levels in the food web, such picoplankton ultrastructural analyses could be pursued with profit as a diagnostic tool. For decades, the ultrastructure of some eukaryotic nanoplankton has been known to vary in specific ways to specific stresses in laboratory experiments. An extension of these structure-function correlations is potentially a useful tool to provide indicators of ecosystem health. The barriers to progress in such research are now understood and can be overcome. Kluwer Academic Publishers, 1992 ultrastructure nationallicence indicator nationallicence picoplankton nationallicence viruses nationallicence algae nationallicence Leppard Gary Rivers Research Branch, National Water Research Institute, Environment Canada, 867 Lakeshore Road, P.O. Box 5050, L7R 4A6, Burlington, Ontario, Canada aut Munawar Mohiuddin Great Lakes Laboratory for Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, Canada Centre for Inland Waters, 867 Lakeshore Road, P.O. Box 5050, L7R 4A6, Burlington, Ontario, Canada aut Journal of Aquatic Ecosystem Health Kluwer Academic Publishers 1/4(1992-12-01), 309-317 0925-1014 1:4<309 1992 1 10813 https://doi.org/10.1007/BF00044172 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00044172 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Leppard Gary Rivers Research Branch, National Water Research Institute, Environment Canada, 867 Lakeshore Road, P.O. Box 5050, L7R 4A6, Burlington, Ontario, Canada aut NATIONALLICENCE 700 1- Munawar Mohiuddin Great Lakes Laboratory for Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, Canada Centre for Inland Waters, 867 Lakeshore Road, P.O. Box 5050, L7R 4A6, Burlington, Ontario, Canada aut NATIONALLICENCE 773 0- Journal of Aquatic Ecosystem Health Kluwer Academic Publishers 1/4(1992-12-01), 309-317 0925-1014 1:4<309 1992 1 10813 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer