Alternative approaches for estimating components of lake metabolism using the free-water dissolved-oxygen (FWDO) method

McNair, James N.; Sesselmann, Meagan R.; Kendall, Scott T.; Gereaux, Leon C.; Weinke, Anthony D.; Biddanda, Bopaiah A.

doi:10.1127/fal/2015/0626

Cited by 9 publications

(21 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We observed that the metabolism model was able to successfully estimate rates for up to 116 more days than the bookkeeping method, likely because the model integrates variability in rates throughout the day (McNair et al 2015). While the bookkeeping approach allows for estimates of GPP and R without assuming any mathematical function, there is an overreliance on the differencing of successive DO concentrations (McNair et al 2013).…”

Section: Discussionmentioning

confidence: 97%

“…Lack of such sensors to characterize the DO dynamics of the full water column remains a challenge for studying whole lake ecosystem metabolism. Metabolism models that incorporate data throughout the water column would likely be able to better reconcile the biological signal relative to physical changes in DO and lead to the estimation of depth-integrated metabolic rates (e.g., Obrador et al 2014, McNair et al 2015.…”

Section: Discussionmentioning

confidence: 99%

“…Incipient eutrophication may be better tracked using highfrequency GPP, R, and NEP. However, open-water metabolism models have not proven entirely effective for analysis of oligotrophic lake metabolism because models can sometimes predict oxygen concentrations that poorly match observed data (McNair et al 2015). Further, due to subtle diel variation in oxygen concentrations in oligotrophic lakes, physical processes may overwhelm the biological signal.…”

Section: Introductionmentioning

confidence: 99%

“…For example, in a global survey of metabolic rates across 25 lakes, two oligotrophic systems, Lake Sunapee, New Hampshire, USA and Sparkling Lake, Wisconsin, USA, had many days with near-zero estimates of GPP and R (Solomon et al 2013). Traditional openwater metabolism models may need modification to capture diel fluctuations in GPP and R in lakes with low productivity (McNair et al 2015).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Intra- and inter-annual variability in metabolism in an oligotrophic lake

et al. 2016

View full text Add to dashboard Cite

Lakes are sentinels of change in the landscapes in which they are located. Changes in lake function are reflected in whole-system metabolism, which integrates ecosystem processes across spatial and temporal scales. Recent improvements in high-frequency open-water metabolism modeling techniques have enabled estimation of rates of gross primary production (GPP), respiration (R), and net ecosystem production (NEP) at high temporal resolution. However, few studies have examined metabolic rates over daily to multi-year temporal scales, especially in oligotrophic ecosystems. Here, we modified a metabolism modeling technique to reveal substantial intra-and interannual variability in metabolic rates in Lake Sunapee, a temperate, oligotrophic lake in New Hampshire, USA. Annual GPP and R increased each summer, paralleling increases in littoral, but not pelagic, total phosphorus concentrations. Storms temporarily decoupled GPP and R, resulting in greater decreases in GPP than R. Daily rates of GPP and R were positively correlated on warm days that had stable water columns, and metabolism model fits were best on warm, sunny days, indicating the importance of lake physics when evaluating metabolic rates. These metabolism data span a range of temporal scales and together suggest that Lake Sunapee may be moving toward mesotrophy. We suggest that functional, integrative metrics, such as metabolic rates, are useful indicators and sentinels of ecosystem change. We also highlight the challenges and opportunities of using high-frequency measurements to elucidate the drivers and consequences of intra-and inter-annual variability in metabolic rates, especially in oligotrophic lakes.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Intra- and inter-annual variability in metabolism in an oligotrophic lake

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Uncertainties that showed up in modeling were most often explained by neglected physical processes, primarily vertical and horizontal transport (Hanson et al ; Staehr et al a ; Solomon et al ; Rose et al ). Indeed, a significant effect of transport on single point DO measurements has repeatedly been demonstrated (Lauster et al ; Sadro et al ; Staehr et al b ; Antenucci et al ; McNair et al ).…”

mentioning

confidence: 92%

Coupled simulation of high‐frequency dynamics of dissolved oxygen and chlorophyll widens the scope of lake metabolism studies

Istvánovics

Honti

2017

Limnology & Oceanography

View full text Add to dashboard Cite

High frequency time series of dissolved oxygen (DO), delayed chlorophyll fluorescence (Chl) and relevant background variables were recorded on nearly 900 d during 7 yr in large, shallow, meso-eutrophic Lake Balaton (Hungary). Novel models were developed for coupled simulation of diel dynamics of DO and Chl using sequential learning and uncertainty assessment in a Bayesian framework. Despite the generally good model fit for both variables, the uncertainty of the metabolic estimates was high, due primarily to the identification problem of individual metabolic processes. Deviations between observed and simulated DO concentrations suggested that neglect of transient stratification might be responsible for the bulk of the systematic model errors. Net ecosystem production (NEP) was uncertain. Unless air-water oxygen exchange can be estimated from direct measurements, the free-water DO method cannot reliably estimate NEP. Gross primary production (GPP) could satisfactorily be hindcasted assuming non-linear multiplicative dependence on Chl, water temperature and light. Hindcast of community respiration (CR) was less successful, possibly due to the impact of local benthic respiration. Results suggested a major shift in lake metabolism at about 168C. Below and above this temperature, 70% and 90% of net primary production could be utilized by heterotrophs within a day, respectively. Indirect evidence suggested that biomass-specific net primary production was determined by phosphorus. The large difference between reproductive rates and net growth rates estimated from GPP and Chl and from daily change in Chl, respectively indicated that loss rates of phytoplankton were as important determinants of algal dynamics as reproductive rates.

show abstract

Dissolved oxygen dynamics under ice: Three winters of high‐frequency data from Lake Tovel, Italy

Obertegger

Obrador

Flaim

2017

Water Resources Research

View full text Add to dashboard Cite

Under‐ice dissolved oxygen (DO) metabolism and DO depletion are poorly understood, limiting our ability to predict how changing winter conditions will affect lake ecosystems. We analyzed under‐ice DO dynamics based on high‐frequency (HF) data at two depths (5 and 25 m) for three winters (January–March 2014, 2015, and 2016) in oligotrophic Lake Tovel (1178 m above sea level; maximum depth 39 m). Specifically, we assessed diel metabolic rates based on HF data of DO, temperature, and light for winter 2016 and seasonal DO depletion rates based on HF data of DO for all three winters. For 2016, calculations of metabolic rates were possible only for 34% and 3% of days at 5 and 25 m, respectively; these metabolic rates generally indicated net heterotrophy at both depths. Low success in modeling metabolic rates was attributed to low diel DO variability and anomalous diel DO patterns, probably linked to under‐ice physical processes. Seasonal DO patterns for the three winters showed increasing, decreasing, or stable DO trends at 5 m while at 25 m patterns always showed decreasing DO trends but with different rates. Our multiyear study permitted us to hypothesize that the observed intraannual and interannual differences in DO depletion can be attributed to variable snow cover determining the penetration of radiation and thus photosynthesis. This study brings new insights to DO dynamics in ice‐covered systems, highlights the challenges linked to under‐ice lake metabolism, and advocates for a modeling approach that includes physical processes.

show abstract

Alternative approaches for estimating components of lake metabolism using the free-water dissolved-oxygen (FWDO) method

Cited by 9 publications

References 1 publication

Intra- and inter-annual variability in metabolism in an oligotrophic lake

Intra- and inter-annual variability in metabolism in an oligotrophic lake

Coupled simulation of high‐frequency dynamics of dissolved oxygen and chlorophyll widens the scope of lake metabolism studies

Dissolved oxygen dynamics under ice: Three winters of high‐frequency data from Lake Tovel, Italy

Contact Info

Product

Resources

About