DOI: 10.5061/dryad.cnp5hqcbz
title: Idiosyncratic phenology of greenhouse gas emissions in a Mediterranean reservoir

description: Extreme hydrological and thermal regimes characterize the Mediterranean
 biome and can significantly impact the phenology of greenhouse gas (GHG)
 emissions in reservoirs. Our study examined the seasonal changes in GHG
 emissions of a shallow, eutrophic, hardwater reservoir in Spain. We
 observed distinctive seasonal patterns for each gas. CH4 emissions
 substantially increased during stratification, influenced predominantly by
 the rise of water temperature and gross primary production and the drop in
 reservoir mean depth. N2O emissions mirrored CH4's seasonal trend,
 significantly correlating to water temperature, wind speed, and net
 primary production. Conversely, CO2 emissions decreased during
 stratification and displayed a quadratic, rather than a linear
 relationship with water temperature -an unexpected deviation from CH4 and
 N2O emission patterns- likely associated with calcite formation coupled to
 photosynthesis. This investigation highlights the need to integrate these
 idiosyncratic patterns into GHG emissions models, enhancing the prediction
 of global GHG emissions in the global change era.
description: This study was conducted at the eutrophic Cubillas reservoir in
 southern Spain, from March 2021 to July 2022. It focused on weekly
 monitoring of CO<sub>2</sub>, CH<sub>4</sub>, and
 N<sub>2</sub>O emissions, capturing both diffusive and
 ebullitive fluxes. Measurements of these greenhouse gases were taken at
 the reservoir's surface using a Cavity Ring-Down Spectrometer
 (PICARRO G2508) connected to a floating chamber, with 4 to 6 readings
 recorded daily during daylight hours. In addition to greenhouse gas
 monitoring, the study also involved assessing environmental and biological
 factors that influence the seasonal patterns of these gases. This included
 measuring water temperature, oxygen concentration, depth, and wind speed.
 Furthermore, nitrate levels, Gross Primary Production (GPP), respiration
 (Res), and Net Ecosystem Production (NEP) were also systematically
 measured and analyzed. Finally, a multiple mixed linear model approach was
 employed to identify the primary drivers of greenhouse gas (GHG)
 emissions.
description: # Idiosyncratic phenology of greenhouse gas emissions in a Mediterranean
 reservoir
 [https://doi.org/10.5061/dryad.cnp5hqcbz](https://doi.org/10.5061/dryad.cnp5hqcbz) Contains 5 files: **(1) analysis.r -** R script to replicates analyses and the figures in the paper and Supplementary Material: **(2) flux_calculations.r** - R script to determine CO2, CH4 and N2O fluxes from floating chamber data.  **(3) Datasets** (3 in total): **(3.1). clean_data.txt**: Comprises the analyzed dataset to reproduce figures and models from the manuscript.          Columns:                   date_time: date and time (year-month-day hour:min: sec)                   rep: sample replicate                   flux_N2O: Nitrous oxide flux (ug N / m2 day)                   flux_CO2: Carbon dioxide flux (mg C / m2 day)                   flux_CH4_diffusive: Methane diffusive flux (mg C / m2 day)                   flux_CH4_ebullitive: Methane ebullitive flux (mg C / m2 day)                   flux_CH4_total: Total methane flux (mg C / m2 day)                         water_level: water level in m                   wind_speed: wind speed in m /s                          ta: water temperature in celsius degree                           GPPC: Gross primary production in mg C / L day                     NPPC: Net primary production in mg C / L day                     CO2eq: Radiative forcing in carbon dioxide equivalents                   date: date in year-month-day **(3.2). Fluxlat.xlsx:** Dataset with fluxes from the literature at a global scale including data from this study. Dataset contains 4 sheets, 3 for each gas, and a forth one including the units.          Columns:                   lat: latitude (degree)                   lon: longitude (degree)                   min: minimum flux value reported (see gases units below)                    max: maximum flux value reported (see gases units below)                    Reference: reference from where fluxes were obtained                   sheet CO2: Carbon dioxide flux (mg C / m2 day)                   sheet CH4_diffusive: Methane diffusive flux (mg C / m2 day)                   sheet N2O: Nitrous oxide flux (ug N / m2 day) **(3.3). fluxes_example.xlsx:** Example dataset for calculating GHG fluxes using the R code “flux_calculations.r”. Dataset contain 3 sheets, including raw data for fluxes, environmental data and the units.          Columns:                   Date: date (d-m-y)                   time: time in seconds (one measurement per second)                   rep: replicate                   N2O_dry: Nitrous oxide in ppm                   CO2_dry: Carbon dioxide in ppm                   CH4_dry: Methane in ppm                   V: Volume of the floating chamber (m3)                   A: Area of the floating chamber (m2)                   P: Atmospheric pressure (Pa)                   R: Universal gas constant (m3 Pa / K mol)                   T: Temperature (Kelvin degree)