Carbon Cycling in the Watershed and Lakes

Bopi Biddanda,Scott Kendall, Eric Strickler, Angie Defore, Maggie Weinert,

Deb Dila, Kaitlyn Driza and Kate Coveney

Annis Water Resources Institute and Lake Michigan CenterGrand Valley State University, MI

Carbon CycleCarbon Cycle

Reevaluation of the Role of Inland WatersReevaluation of the Role of Inland Waters

a) Traditional view of carbon transport from terrestrial environment to oceans, b) Modern view of carbon transport showing inland waters as reactive sites of carbon metabolism (Cole et al. 2007).

Muskegon Lake - fed by Muskegon River(background) flowing into Lake Michigan(foreground).www.co.muskegon.mi.us

Freshwater ecosystems are major sites of C processing!

River to lake gradient

Transition

Visible trophic level changes occur along the Land to Lake gradient!

Visible Mesoscale River Runoff into Lake Michigan

Rivers link Land-derived C & Nutrients to the Lake via Aquatic Microbes!Johengen et al. JGLR, 2008

Grand River

Photo credit: Marge Beaver, Muskegon

Massive Sediment Resuspension event 3/98Total Suspended Matter (surface reflectence) in Surface Waters

Aquatic microorganisms link terrestrial organic matter and nutrients to aquatic productivity (Biddanda and Cotner, 2002).

Lake Michigan

Toast to a Lake BrewWhen rain runs down-river to the lake

Where wicked winds stir the lotYou know the brew is in the coastal pot!

As plankton go nuts over N and PWith little light in which to see

Animals dine on resuspended wasteProduction and respiration peak in haste!

Then as rivers slow and winds subsideThe placid lake takes it in stride

Returns to its native serene state of blueAnd is ready for another dose of home-brew!

–Bopi BiddandaIAGLR, May 2009; ASLO Bulletin 2009.

Storm of October 2010

Methods

• Respiration (R) and Production (P) were measured by tracking changes in dissolved oxygen concentrations in BOD bottle incubations under insitu conditions over a daily cycle.

• R = Dark bottles• NPP = Light Bottles• GPP = R + NPP

Controls, Light and Dark Bottles

Plankton Metabolism: Land to Lake Gradient in Lake Michigan

Decreasing Net Primary Production Along the Land to Lake Gradient

Average NPP (2002-2008), Lake Michigan Transect

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M-110 M-45 M-15 ML-C Muskegon LkSite

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Plankton Metabolism: Land to Lake Gradient in Lake Michigan

Decreasing Plankton Respiration Along the Land to Lake Gradient

Average R (2002-2008), Lake Michigan Transect

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M-110 M-45 M-15 ML-C Muskegon LkSite

R(u

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Plankton Metabolism: Land to Lake Gradient in Lake Michigan

Decreasing Gross Primary Production Along the Land to Lake Gradient

Average GPP (2002-2008) Lake Michigan Transect

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M-110 M-45 M-15 ML-C Muskegon LKSite

GPP

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Plankton Metabolism: Land to Lake Gradient in Lake Michigan

Production drops much faster than R along the Land to Lake Gradient!

Average R and GPP (2002-2008), Lake Michigan Transect

y = 41.81x - 29.011R2 = 0.9432

y = 130.63x - 195.95R2 = 0.957

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RLinear (R)

Linear (GPP)

Lake Land

River GPP > R (C sink). Lake GPP < R (C source)

DayDay--Night Oxygen Cycle in Muskegon Lake May 2009Night Oxygen Cycle in Muskegon Lake May 2009

Muskegon Lake Open Water Metabolism (6-9 May 2009)

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14:4

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Time (hours)

Sonde 4Sonde 5Sonde 6

“Production and respiration are two sides of the same metabolic coin - the yin an yang of the biosphere”

Muskegon Lake Metabolism 2008Muskegon Lake Metabolism 2008--0909Seasonal CycleSeasonal Cycle

•• Predictable patterns in GPP:R ratioPredictable patterns in GPP:R ratio–– during the spring and summerduring the spring and summer–– during fall and winterduring fall and winter

Sink to Source? Effect of Climate Warming on Plankton Metabolism in Muskegon Lake

Plankton and Temperature: Schematic diagram of hypothesized results and actual findings. P refers to Gross Primary Production of Plankton and R refers to Plankton Respiration. The horizontal P/R line refers to the 1:1 line where P and R are increasing at the same rate (left). The decreasing P/R line refers to R increasing more than P as waters warm (right).

Observations• Respiration is a major fate of current as well as past

primary production in Lake Michigan.• Terrestrial inputs of carbon and nutrients

support significant respiration and production in the Lake.

• As production declines more than respiration along the Land to Lake gradient, the relative role of respiration increases - with nearshore net autotrophic systems giving way to net hetrotrophic systems offshore.

• Spring-summer net autotrophy and fall-winter net heterotrophy trends are observed regularly.

• As lakes warm, Respiration may exceed Productionshifting lakes from sinks to sources of C

• There is a need for continuous lake observatories.

Muskegon Lake Observatory for Ecosystem Changes

Real-time Continuous Lake News!

Lake Carbon Cycle

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Funding: NSF, NOAA, MSGC