Lake‐size dependency of wind shear and convection as controls on gas exchange

Read, Jordan S.; Hamilton, David P.; Desai, Ankur R.; Rose, Kevin C.; MacIntyre, Sally; Lenters, John D.; Smyth, Robyn L.; Hanson, Paul C.; Cole, Jonathan J.; Stæhr, Peter A.; Rusak, James A.; Pierson, Donald C.; Brookes, Justin D.; Laas, Alo; Wu, Chin H.

doi:10.1029/2012gl051886

Cited by 235 publications

(266 citation statements)

References 32 publications

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“…In this transition region, we expect maximum change in ice cover duration, mixing regime shifts and wind-driven turbulent mixing, especially for large lakes (e.g., [18]). In deep lakes that stably stratify, the deepwater trends are more reflective of late winter and early spring conditions during turnover and onset of stratification, including wind-driven mixing following ice-off, as opposed to annual or summer air temperatures [59,60]. Underlying geology can affect deepwater temperature through modifications of groundwater fluxes [18] and sediment heat storage in the shallower zones of lakes [61].…”

Section: Deepwater Trendsmentioning

confidence: 99%

Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)

Richardson

Melles

Pilla

et al. 2017

Water

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Lake surface water temperatures are warming worldwide, raising concerns about the future integrity of valuable lake ecosystem services. In contrast to surface water temperatures, we know far less about what is happening to water temperature beneath the surface, where most organisms live. Moreover, we know little about which characteristics make lakes more or less sensitive to climate change and other environmental stressors. We examined changes in lake thermal structure for 231 lakes across northeastern North America (NENA), a region with an exceptionally high density of lakes. We determined how lake thermal structure has changed in recent decades and assessed which lake characteristics are related to changes in lake thermal structure. In general, NENA lakes had increasing near-surface temperatures and thermal stratification strength. On average, changes in deepwater temperatures for the 231 lakes were not significantly different than zero, but individually, half of the lakes experienced warming and half cooling deepwater temperature through time. More transparent lakes (Secchi transparency >5 m) tended to have higher near-surface warming and greater increases in strength of thermal stratification than less transparent lakes. Whole-lake warming was greatest in polymictic lakes, where frequent summer mixing distributed heat throughout the water column. Lakes often function as important sentinels of climate change, but lake characteristics within and across regions modify the magnitude of the signal with important implications for lake biology, ecology and chemistry.

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Section: Deepwater Trendsmentioning

confidence: 99%

Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)

Richardson

Melles

Pilla

et al. 2017

Water

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“…On the other hand, waterside CO 2 partial pressure may be so high under these circumstances that the assumption of standard atmospheric partial pressures of CO 2 does not lead to major errors in flux calculations. It may be more critical to apply gas exchange velocities calculated from empirical models not specifically adjusted to the habitat in focus (Vachon and Prairie, 2013;Read et al, 2012). 15…”

Section: Discussionmentioning

confidence: 99%

“…The gas exchange velocity is influenced by near-surface turbulent mixing driven by wind shear and convection (Zappa et al, 2007;Read et al, 2012). Measurements of F and the concentration gradient (C water -C air ) allow calculation of k. Empirical models of gas exchange velocity have often been parameterised from wind speed (Cole and Caraco, 1998;Crusius and Wanninkhof, 2003).…”

Section: Introductionmentioning

confidence: 99%

“…This approach can potentially result in erroneous estimates of gas flux due to system scale 10 differences in additional drivers of gas exchange velocity Vachon and Prairie, 2013). For example, the contribution of convection to near-surface turbulence relative to wind shear increases with decreasing lake size (Read et al, 2012). The influence of convection on gas exchange velocity and the resulting gas flux may thus be missed if not accounted for Podgrajsek et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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A simple and cost-efficient automated floating chamber for continuous measurements of carbon dioxide gas flux on lakes

Martinsen¹,

Kragh²,

Sand‐Jensen³

2018

Preprint

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Abstract. Freshwaters emit significant amounts of CO 2 on a global scale. Yet, emissions remain poorly constrained from the diverse range of aquatic systems. The drivers and regulators of CO 2 gas flux from standing waters require further investigation to improve knowledge on both global scale estimates and system scale carbon balances. Often lake-atmosphere gas fluxes are estimated from empirical models of gas transfer velocity and air-water concentration gradient. Direct 10 quantification of the gas flux circumvents the uncertainty associated with the use of empirical models from contrasting systems. Existing methods to measure CO 2 gas flux are often expensive (e.g. eddy-covariance) or require a high workload in order to overcome the limitations of single point-measurements using floating chambers. We added a small air pump, timer and an exterior tube to ventilate the floating chamber headspace and passively regulate excess air pressure. By automating evacuation of the chamber headspace, continuous measurements of lake CO 2 gas flux can be obtained with minimal effort. 15We present the chamber modifications and an example of operation from a small forest lake. The modified floating chamber performed well in the field and enabled continuous measurements of CO 2 gas flux with 40-minute intervals. Combining the direct measurements of gas flux with measurements of air and waterside CO 2 partial pressure also enabled calculation of gas exchange velocity. Application of the described floating chamber is straightforward and modifications are both simple and cost-efficient to perform. Changing the chamber dimensions to particular applications and systems makes this approach to 20 measure gas flux flexible and appropriate in a range of different systems.

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“…The network includes lakes with instrumented sites ranging from <1 ha (Trout Bog, WI) to thousands of hectares (Lake Rotorua, NZ); eutrophic lakes (Lake Mendota, WI), oligotrophic lakes (Lake Sunapee, NH), and brown-stained lakes (Lac Feagh, Ireland); large shallow lakes (Taihu, China) and deep lakes (Lake Tanganika, Africa); and alpine lakes (Alpine Lake Observatory, France), subtropical lakes (Yuan Yang Lake, Taiwan), and lakes from Antarctica (Bonnie Lake). This diversity provides opportunities to develop generalized understanding across large ecosystem gradients (e.g., Read et al 2012, Solomon et al 2013, O'Reilly et al 2015 and potentially develop globally relevant relationships .…”

Section: Integrating Network Of People Ecosystems and Data To Advamentioning

confidence: 99%

Networked lake science: how the Global Lake Ecological Observatory Network (GLEON) works to understand, predict, and communicate lake ecosystem response to global change

2016

Self Cite

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The Global Lake Ecological Observatory Network (GLEON) has built an international, grassroots network of scientists and citizens, data, and lake observatories to advance understanding of lake ecosystems. Through careful attention to the professional needs and aspirations of a community, GLEON has formed as its foundation the trust and respect essential to product-based network science. As a consequence, GLEON is making significant advancements in lake ecosystem understanding through all "five legs of the table that support scientific understanding"-natural history, multiscale data, experiments, theory, and comparative studies-with particular emphasis on multiscale data and comparative studies. Technical products, such as cyberinfrastructure in support of network data and operations, software tools for calculating lake physical metrics (e.g., thermocline depth, buoyancy frequency, Schmidt stability), and lake metabolism, as well as ecosystem-scale numerical simulation software, have derived from GLEON collaborations and have become community resources catalyzing interdisciplinary science. Education and outreach initiatives have served to engage citizens from outside the traditional boundaries of academia directly in research. Moreover, these cross-boundary collaborations have provided essential links to lake and reservoir stakeholders who have informed how science is prioritized and communicated within GLEON. As a grassroots network, GLEON derives its momentum, flexibility, and impact from its talented members, who are committed to the future sustainability of lakes and reservoirs and the services they provide.

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Lake‐size dependency of wind shear and convection as controls on gas exchange

Cited by 235 publications

References 32 publications

Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)

Transparency, Geomorphology and Mixing Regime Explain Variability in Trends in Lake Temperature and Stratification across Northeastern North America (1975–2014)

A simple and cost-efficient automated floating chamber for continuous measurements of carbon dioxide gas flux on lakes

Networked lake science: how the Global Lake Ecological Observatory Network (GLEON) works to understand, predict, and communicate lake ecosystem response to global change

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