The Distribution of Mercury in the Surficial Sediments of Lake Huron

Total mercury has been determined in 163 samples of the topmost 3 cm of sediment taken from Lake Huron during 1969. Total mercury values range from 54 to 805 p.p.b. with a mean of 222 p.p.b. and a standard deviation of 162 p.p.b. The mercury distribution in the lake sediments shows a trend for increasing concentration from nearshore and mid-lake shallow water, coarse sediment deposits outwards into the fine-grained sediments in the deeper water basins. The application of a quartz correction to compensate for the dilution by an inert constituent reveals two major anomalies of higher mercury concentration. The Saginaw anomaly occurs in the southern basins of the lake and is believed to be due to the input of industrial mercury from Saginaw Bay; the Bruce anomaly in the northeastern part of Manitoulin basin is believed to be due to the weathering of sulfide deposits with subsequent concentration in the lake sediments being related to major water circulation patterns in the lake. From statistical analysis the mercury is believed to be bound in the sediments predominantly adsorbed or complexed by organic matter with subsidiary adsorption by the surfaces of iron sulfides and hydrated iron oxide – inorganic phosphorus complexes.

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WIND-DRIVEN CIRCULATION OF SAGINAW BAY

Coastal Engineering Proceedings ◽

10.9753/icce.v15.186 ◽

1976 ◽

Vol 1 (15) ◽

pp. 186

Author(s):

James H. Saylor ◽

Larry J. Danek

Keyword(s):

Water Surface ◽

Major Axis ◽

Lake Huron ◽

Prevailing Wind ◽

Saginaw Bay ◽

Open Mouth ◽

Flushing Rate ◽

Circulation Patterns ◽

Lagrangian Measurements ◽

Good Agreement

A combination of Lagrangian measurements and fixed current meter moorings were used during the summer of 1974 and the winter of 1974-75 to determine the circulation patterns of Saginaw Bay. Because the bay is shallow, the water responds rapidly to wind changes. Distinct circulation patterns were determined for southwest and northeast winds. These directions parallel the major axis of the bay and were the prevailing wind directions during the study. A typical exchange rate between the inner , _. and outer bay during moderate winds aligned with the bay axis is 3700 m s '~s If sustained, this flushing rate would completely exchange the water of the inner bay in about 26.5 days. However, winds perpendicular to the axis of the bay cause little water to be exchanged and the residence time of water in the bay is much longer. Comparison of measured currents with the results of an indpendently-developed numerical model for the bay indicates there is good agreement between the observations and the simulation of the circulation in the shallow inner bay. Agreement is poor in the deeper outer bay, where specification of proper boundary conditions at the open mouth of the bay is important for meaningful model simulations. Ice cover during winter shields the water surface from wind stress. Currents are sluggish and driven almost entirely from interactions with the lakescale circulation of Lake Huron.

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Zooplankton Grazing During the Zebra Mussel ( Dreissena polymorpha ) Colonization of Saginaw Bay, Lake Huron

Journal of Great Lakes Research ◽

10.1016/s0380-1330(95)71067-x ◽

1995 ◽

Vol 21 (4) ◽

pp. 567-573 ◽

Cited By ~ 29

Author(s):

Thomas B. Bridgeman ◽

Gary L. Fahnenstiel ◽

Gregory A. Lang ◽

Thomas F. Nalepa

Keyword(s):

Zebra Mussel ◽

Dreissena Polymorpha ◽

Lake Huron ◽

Zooplankton Grazing ◽

Saginaw Bay

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Direct Determination of Apatite in Lake Sediments

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-080 ◽

1980 ◽

Vol 37 (4) ◽

pp. 640-646 ◽

Cited By ~ 9

Author(s):

R. P. Reid ◽

C. H. Pharo ◽

W. C. Barnes

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Lake Sediments ◽

Trophic State ◽

Inorganic Phosphorus ◽

Source Rocks ◽

Emission Spectrometry ◽

Phosphorus Load ◽

Lake Trophic State ◽

Scanning Electron

Apatite is a common accessory mineral in the source rocks for the glacial debris supplying sediments to many Canadian lakes. A method has been developed which uses scanning electron microscopy and energy dispersive X-ray emission spectrometry for direct identification of apatite. This method has been used to examine the apatite content of various size fractions in Kamloops Lake sediments. Apatite concentrations obtained by this direct examination correlate well (r > 0.999) with apatite concentrations determined by chemical analyses and indicate that, in addition to comprising as much as 70% of the total phosphorus load, apatite may comprise as much as one-third of the "dissolved" (< 0.45 μm) inorganic phosphorus load. Consequently the use of classical (e.g. Vollenweider 1968; Vollenweider and Dillon 1974) methods of estimating lake trophic state from inorganic phosphorus concentrations in lake water must be done with care, recognizing that the bulk of inorganic phosphorus in lakes deriving sediment from glaciated igneous or metamorphic terrains may be in the form of apatite.Key words: apatite, lake, trophic state, phosphorus load, scanning electron microscopy

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