Metabolism Working Group Update GLEON 13

Metabolism data sets Thanks to GLEON members and affiliated sites for data contributions! – 25+ sites have contributed high resolution (e.g. ~30 minute or higher frequency) data. – Data set includes DO, sensor temperature, profile temperature (e.g. 7 temperatures over a 15m water column), wind speed, and PAR. – Data ranges from ~125 days to 365 days for each lake. – Additional ancillary data includes mean Chl, DOC, Kd, TP, TN, etc over date range.

Ongoing Metabolism Projects (4) Pre-GLEON 12 Comparison of GPP, R, and NEP among 25 lakes – Solomon et al.; MS in preparation Night-time patterns in R in Mendota – Kafura and Solomon; MS in submission Night-time patterns in R among 25 lakes – Sadro, Holtgrieve, Koch, and Solomon; Analysis ongoing The role of lake physics in regulating estimates of ecosystem metabolism – K. Rose, L. Winslow, J. Read, and E. Kara; MS completed and will soon be submitted to L&O

Projects begun at G12 (2) Comparison of methods used to production (GPP, PP) – Alo Laas leading; methods include C14, high frequency DO, and empirical modeling. – Data from 4 sites (Acton, Kinneret, Frederiksborg Slotsso, Vortsjarv). Other sites welcome. – See Alo’s poster for more details. Linking high frequency estimates of ecosystem metabolism and chlorophyll fluorescence – Data from 13 sites collected

25 Lake GPP/R/NEP Comparison Patterns of temporal variability in R quite different among lakes Temperature and GPP control 37-94% of within-lake variation in R. Slope of relationship with GPP differs among lakes – Eutrophic lakes: low slope – Oligotrophic /dystrophic lakes: high slope

Gordon Holtgrieve, Gregory Koch, Steve Sadro, Chris Solomon - Widespread recognition of diel variability in R; few studies have explicitly evaluated variability in patterns - GLEON sites provide data for the evaluation of patterns in nighttime R along trophic and DOC gradients Diel Patterns in Respiration

Previous GLEON meetings (GLEON 10 – 11) – Preliminary analysis of patterns in ~3 GLEON lakes – Adapt R code from C. Solomon to access only relevant nighttime data. Working group meeting (Montreal: Jan 16-19, 2011) – Characterize mechanisms underlying specific models of respiration – Test 3 – 4 models using AIC – Begin literature search and draft MS introduction Preliminary analysis complete and work Fine tuning before final analysis and write up Diel Patterns in Respiration: Progress to Date

The Role of Physics in Estimates of Lake Metabolism Physical processes can regulate DO dynamics on the scale of hours to days; estimates of metabolism may be affected by these processes Goal of Research: Understand if/how metrics of lake physics are related to estimates of GPP/R/NEP and/or variability in these parameters Techniques: Use Lake Analyzer to calculate physical stability parameters in GLEON lakes; estimate variability via bootstrapping. Compare stability parameters and PAR to metabolism parameters & variance in parameters. Kevin Rose, Luke Winslow, Jordan Read, Emily Kara, Chris Solomon

Physics/Metabolism: Progress to Date Data analysis from 17 sites completed Manuscript completed; to be submitted to L&O very soon Example: Lake Annie, August 2008

Metabolism methods comparison GPP and PP estimated in Acton Lake, Ohio (from Mike Vanni)

Product of synergies between signal processing and metabolism WGs, initiated by Peter Staehr Data request sent out in May 2011 requesting DO data from data providers who had already supplied Chl a data to the signal processing group. – 13 lakes have contributed data to date. Liz Ryder and Elvira have collected data. The also solicited people interested in running the analyses. – Chris Solomon and Luke Winslow have volunteered to generate and run metabolism code. – Project seeks to involve more people. Chl a fluorescence / DO metabolism sub group

Country Lake Year of Dataset Chl a fluor Air Temp Water Temp DO (mg/l) PAR Wind Speed Contact USALake Lillinonah2010yes - Jen Klug USAKentucky Lake2008yes Susan Hendricks USAMendota2009yes ? L.Winslow/L. Beversdorf DenmarkVedsted2008yes Peter Staehr IrelandFeeagh yes E. de Eyto/L. Ryder N. Z.Tutira yes ?solar rad.yes Chris Mc Bride FinlandVanajanselk2010yes Lauri Arvola EstoniaVortsjarv2010yes Alo Laas HungaryBalaton2009yes ?solar rad.yes Vera Istvanovics GermanyMüggelsee2010yes R. Adrian/H. P. Grossart N. Z.Ngaroto yes ? Chris Mc Bride ChinaTaihu2009yes Guangwei Zhu / C. McBride N. Z.Waikaremoana yes Chris Mc Bride Sites that have contributed metabolism and Chl fluorescence data

Example: Chlorophyll fluorescence and metabolism Heart Lake, Montana July-August 2010 (from Kevin Rose)

Potential directions for this meeting Depending on number of people and their interests: Identify a leader for the high-frequency DO and Chl fluorescence sub-group; meet and begin analysis? Other sub groups need dedicated working group time? Round table discussion of new questions that GLEON lake datasets may be used to address...