BIOLOGY 2F03 Lecture 3: Chapter 3

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 2F03
• Professor: Lovaye Kajiura

Document Summary

The hydrologic cycle (exchanges water among reservoirs: water enters reservoir as precipitation or surface/subsurface flow and exits thorough evaporation/flow. 20% freshwater found in canada, 65% freshwater is in glacier/ice fields, 30% is groundwater. Al(cid:271)e(cid:396)ta"s gla(cid:272)ie(cid:396)s a(cid:396)e (cid:396)et(cid:396)eati(cid:374)g. ag(cid:396)i(cid:272)ultu(cid:396)al la(cid:374)d depe(cid:374)ds o(cid:374) (cid:449)ate(cid:396) (cid:272)o(cid:373)i(cid:374)g f(cid:396)om mountains. In the north hot water is pumped into tar sands, extracting thick oil. A lot of water is being diverted and used for hydro power to po(cid:449)e(cid:396) hu(cid:373)a(cid:374) a(cid:272)ti(cid:448)ities. Wetla(cid:374)d"s (cid:272)a(cid:374) slo(cid:449) flo(cid:449), (cid:396)e(cid:373)o(cid:448)e polluta(cid:374)ts, pe(cid:396)(cid:373)it g(cid:396)ou(cid:374)d(cid:449)ate(cid:396) (cid:396)e(cid:272)ha(cid:396)ge, o(cid:374)ly if they are on landscape. Turnover time: time required for entire volume of certain reservoir to be renewed. Reservoir size and rate of water exchange determine turnover time. Water in atmosphere turns over about every 9 days. Lake renewal from days to centuries) depending on depth/area/ rate of drainage). Ocean renewal rate is 3100 years, 1. 3 billion km3 of water turned over 30 times in last 100,000 years.