Lake Water and Sediment: I. Characteristics and Water Chemistry of Some Canadian East Coast Lakes1

Sixteen lakes are described, varying in geology and all but Iwo of low productivity, and including three acid bog types. A method is described for indirect estimation of the sum of Na and K. In lakes generally, low pH is related to low conductivity, but in these coastal lakes the Na in ocean spray keeps up the conductivity even in very acid waters. At cquilibrium the inorganic P in solution is 2-3 ppb and reprcscnts a residual soluble fraction, independent of productivity and pII. Total P is 10-15 ppb and the concentration is not related to productivity. There is an annual cycle of inorganic I’ with a winter maximum, spring decline, and summer minimum. Methyl orange alkalinity varies dircclly with the sum of Ca and Mg and with either of the ions separately. The scatter in the regression of alkalinity versus Mg is greater than that of alkalinity versus Ca. Them is a reduction of per cent organic material in the sediments directly rclatcd to increasing alkalinity. The cause is attributed to greater bacterial activity as Lhe pI1 goes up. These papers are in continuation of studies related to the productivity of some east coast Canadian lakes. The lakes sclectcd exhibit considerable variety of type and geology, as shown by their map locations (Fig. 1). I‘ ‘ram the work of M. W. Smith the capacity of many of the lakes to support fish is known, providing a standard by which to judge other estimates. The following notes on the lakes will supplcmcnt Figure 1 and Table 1. Lakes 1, 2, and 3 arc located near IIalifax in forbidding granite country. No. 1 is a clearwater primitive, No. 2 an extreme acid bog type, and No. 3 moderately acid bog. Lakes 4, 5, and 6 are near Yarmouth in a quartzite-slate formation, No. 4 being an acid bog type. Their quality indices, based on fish, are respectively 0.20, 0.53, and 0.98, where 1 . O would bc average (Hayes 1957). Lakes 7 to 11 are scattered over Nova Scotia. Nos. 7 and 8 arc not far apart in a sandstone-shale conglomerate. The drainage area of No. 8 supports marginal farming, and the lake has a quality index of 0.36. Grand Lake, No. 9, is the largest and 1 Acknowledgement is made of linancial support by the Nova Scotia llcsearch Foundation and National Research Council of Canada. WC thank a dozen students who participated, and especially James Rose. deepest of the group and known for its landlocked salmon. It drains quartzite-slate from the south, and a conglomerate of shale, sandstone, and lime from the north where farms are situated. The same conglomerate surrounds Lily Lake, No. 10, also in a farming area. The water is too warm for trout. Lake 11 is in altered sediment and igneous rocks. Its quality index is 0.87. Lakes 12, 13, and 14 are close together near St. Rndrews, in a granite area. Their quality indices are low, being respectively 0.28, 0.31, and 0.09. Finally, lakes 1.5 and 16 are in the best trout area of the region, where up to 50 lbs per acre arc taken annually. Like practically all ponds in Prince Edward Island, they are artificial, retained by mill dams a century or more old. Trout are plentiful not only because of good drainage but because the water keeps cool all summer and competitors have not crossed from the mainland. The quality indices are 6.2 and 5.5. The area is one of sandstone, shale, and conglomerate.