Lakes in Winter

NORTH AMERICAN LAKE NONPROFIT ORG. MANAGEMENT SOCIETY US POSTAGE 1315 E. Tenth Street PAID Bloomington, IN 47405-1701 Bloomington, IN Permit No. 171 Lakes in Winter in Lakes L L INE Volume 34, No. 4 • Winter 2014 Winter • 4 No. 34, Volume AKE A publication of the North American Lake Management Society Society Management Lake American North the of publication A AKE INE Contents L L Published quarterly by the North American Lake Management Society (NALMS) as a medium for exchange and communication among all those Volume 34, No. 4 / Winter 2014 interested in lake management. Points of view expressed and products advertised herein do not necessarily reflect the views or policies of NALMS or its Affiliates. Mention of trade names and commercial products shall not constitute 4 From the Editor an endorsement of their use. All rights reserved. Standard postage is paid at Bloomington, IN and From the President additional mailing offices. 5 NALMS Officers 6 NALMS 2014 Symposium Highlights President 11 2014 NALMS Awards Reed Green Immediate Past-President 15 2014 NALMS Photo Contest Winners Terry McNabb President-Elect 16 2014 NALMS Election Results Julie Chambers Secretary Sara Peel Lakes in Winter Treasurer Michael Perry 18 Lake Ice: Winter, Beauty, Value, Changes, and a Threatened NALMS Regional Directors Future Region 1 Wendy Gendron 28 Fish in Winter – Changes in Latitudes, Changes in Attitudes Region 2 Chris Mikolajczyk Region 3 Imad Hannoun Region 4 Jason Yarbrough 32 A Winter’s Tale: Aquatic Plants Under Ice Region 5 Melissa Clark Region 6 Julie Chambers 38 A Winter Wonderland . of Algae Region 7 George Antoniou Region 8 Craig Wolf 44 Water Monitoring Region 9 Todd Tietjen Region 10 Frank Wilhelm 48 Winter Time Fishery at Lake Pyhäjärvi Region 11 Anna DeSellas Region 12 Ron Zurawell At-Large Nicki Bellezza Student At-Large Ted Harris 51 Literature Search LakeLine Staff Editor: William W. Jones Advertising Manager: Philip Forsberg Production: Parchment Farm Productions Printed by: Metropolitan Printing Service Inc. ISSN 0734-7978 ©2014-15 North American Lake Management Society 4510 Regent Street Suite 2A Madison, WI 53705 (All changes of address should go here.) Permission granted to reprint with credit. Address all editorial inquiries to: Advertisers Index William Jones 1305 East Richland Drive Bloomington, IN 47408 Aquarius Systems, Inc. 2 Tel: 812/334-3485 Beagle Bioproducts 5 [email protected] On the cover: Marrone Bio Innovations 2 Address all advertising inquiries to: Ice-on day (Jan. 20, 2007) for Lake Mendota Philip Forsberg PhycoTech BC NALMS WI, with Lake Monona soon to follow. This Scientific Diving International 43 PO Box 5443 was one of the latest dates of ice-on for Madison, WI 53705-0443 Mendota – the second-latest in the last 156 SePRO IFC Tel: 608/233-2836 years. Photo by Peter W. Schmitz provided in Vertex Water Features 27 Fax: 608/233-3186 [email protected] memory of his daughter, Jennifer Erin Schmitz. YSI 1 Winter 2014 / LAKELINE 3 Lakes in Winter Lake Ice: Winter, Beauty, Value, Changes, and a Threatened Future John J. Magnuson and Richard C. Lathrop hat is special about lake ice? and the lake cools to temperatures of 4°C thus the limnological conditions under First, the limnology of the lake or less, the water cooler than 4°C floats the ice. One might expect that water at Wis transformed to a new state, above the warmer water below. When the undersurface of the ice would be unique to ice-covered lakes. Second, ice water temperatures reach 0ºC at the lake 0°C and at the bottom of the lake would associated with lakes provides a beauty surface, ice can begin to form. Regardless, be 4°C. However, in the real world the not gifted to us from lakes without ice. under-ice water temperatures, while temperatures under the ice differ greatly Third, lake ice has value to humans for colder than summer waters, are still above from lake to lake (Figure 1) ecological and cultural services and, at freezing and support aquatic life, even on Ice cover formation is delayed in times, even goods. Fourth, trends and the coldest days that we experience. larger, deeper lakes compared with variability in ice cover signal changes in Winter conditions begin to develop smaller, shallower lakes for two reasons. climate; ice cover can be a miner’s canary, as soon as ice covers a lake and initiates First, lakes with larger volumes of water warning us of environmental changes. sequential changes in physics, chemistry, take longer to lose their heat in fall. Fifth, the sensitivity of lake ice to a and biology. Lake area and depth greatly Second, even after the lake’s average warming climate indicates the future of influence the formation of ice cover and water temperature reaches 4°C and ice cover is threatened by human activity. Winter One way to define the start of winter for temperate and boreal lakes is by the date on which ice first covers an entire lake (see cover photo). Ice cover’s arrival denotes a change in state, dramatically altering lake mixing, light penetration, chemistry, biology, and as importantly, our human interactions with a lake. The first date of complete ice cover would rarely be coincident with December 21, the winter solstice. Similarly, the last date of complete ice cover in late winter or early spring would rarely be coincident with the vernal equinox on March 21. Using ice cover to define limnological winter means that the winter period differs among regions, among lakes in the same area, and among years for the same lake. Two consequences of using ice on and ice off of a lake to delineate the winter mode is that the actual duration of winter is a numerical variable and that it heralds the presence of winter conditions and under- Figure 1. Under-ice water temperatures are warmer in smaller, shallower lakes; ice-on dates were ice processes in individual lakes. sooner in the smaller, shallower lakes (Wisconsin lakes, 2008; see text for explanation). Southern The maximum density of freshwater Wisconsin: Lake Wingra (area 140ha, depth 4m, ice on Nov. 30), Lake Mendota (3,985ha, 25m, is 4°C, so in the fall at temperatures above Dec. 25). Northern Wisconsin: Allequash Lake (north basin 112ha, 8m, Nov. 23), Big Muskellunge 4°C, warmer water floats above the cooler Lake (377ha, 19m, Dec. 3), and south Trout Lake (1,545ha, 32m, Dec. 10) (water temperature waters. However, as winter approaches data: https://lter.limnology.wisc.edu). 18 Winter 2014 / LAKELINE surface waters cool to 0°C on calm cold nights, ice cover is delayed more for larger than for smaller lakes. Larger lakes have longer fetches for the wind to impart its energy to the water surface and that generates greater water column mixing and larger surface waves. The larger surface waves break up thin ice that begins to form initially around the edges of the lake. With the greater wind-driven mixing and the destruction of early ice at the shoreline, larger lakes generally have water column temperatures significantly less than 4°C before the lake surface freezes over (Figure 1). The effect of heating from the lake’s bottom sediments, especially in shallow lakes, is also apparent in under-ice profiles. With the first snow on the ice, light levels greatly decline because snow reflects the light and little is transmitted to the ice and the waters below. Clear ice actually transmits light even better than clear water. However, snowfall on thin ice Figure 2. Vertical section of lake ice showing grey ice from frozen slush at top and clear ice below can weigh the ice down and water seeps – Trout Lake, Vilas County WI, Feb. 2000. Small bubbles in clear ice are likely from dissolved through ice cracks upward into the snow. gases in the water that were extruded as the water froze. Photo: Carl J. Bowser. This slushy snow then freezes to produce grey ice above the clear “black” ice that Through various processes, phosphorus, larger diatoms even can fasten to the formed first (Figure 2). ammonium, and sulfide also build up, undersurface of the ice. However, some A series of chemical and biological especially in eutrophic lakes, as does smaller diatoms flourish in the water changes begin soon after a lake becomes carbon dioxide. If the duration and degree under the ice especially in late winter as ice-covered. Bacteria decompose of anoxia is extensive, then methane is light levels increase. Some currents and organic matter near the sediment water produced in the sediments. Methane gas, mixing does occur but so much less than boundary and thereby reduce dissolved because it is insoluble, forms bubbles in the open water period. oxygen concentrations, a condition that that rise to become imbedded in the ice In terms of mixing and thermal is accelerated in nutrient-rich, eutrophic or coalesce as larger bubbles under the stratification, the period of ice cover lakes. Layers of water with little or no ice. When ice breaks up in spring the lake can be thought of as one of the four dissolved oxygen begin to form at the releases the trapped methane into the air seasons for a deeper lake and as a reset bottom of the lake and expand upward. as well as a puff of carbon dioxide from mechanism for the lake’s biology and In shallow lakes this de-oxygenation the supersaturated water brought to the ecology before spring begins a new can reach the undersurface of the ice surface as the lake mixes. year. If this under-ice period were lost, causing fish “winterkill” to occur.

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