Sensor parameter
Relevance to freshwater C processes and emissions
Example studies (citations in [] are open-source sensor examples)
cDOM, tryptophan-like fluorescence, and absorption at 254nm Measures fractions of organic matter and correlates with DOC and Total organic Carbon (TOC) to understand c cycling (Spencer et al., 2009, Lee et al., 2015)
Chlorophyll a and Phycocyanin Represents processes of algae growth and primary production (Chegoonian et al., 2022, Peipoch & Ensign, 2022)
CO2/CH4 gas flux chambers Provides direct measurements of GHG emitted from water surfaces (McClure et al., 2021, Zheng et al., 2022) [(Duc et al., 2013, Maher et al., 2019)]
Dissolved CO2 / CH4 Dissolved GHG that can be potentially emitted (Roberts et al., 2007, Crawford et al., 2017) [(Butturini & Fonollosa, 2022)]
Dissolved oxygen Primary production produces oxygen whilst respiration consumes it. (Aspray et al., 2017, Mejia et al., 2018, Jankowski et al., 2021) [(Chan et al., 2021)]
Electrical conductivity Hydrological tracer within open system calculations of river metabolism (Vieweg et al., 2016) [(Mendez-Barroso et al., 2020)]
Nitrate Primary production can serve as an important nitrate sink (Jarvie et al., 2018, Murray et al., 2020)
pH Significant control on most biological processes, and influences bicarbonate buffering system, thus dissolved CO2 (Hong et al., 2021, Klemme et al., 2022)
Turbidity Elevated turbidity/sedimentation can block sunlight to primary producers, reducing primary production (Snyder et al., 2018, Honious et al., 2022) [(Droujko et al., 2023)]
Water level Indicates changes in flow, which influence the rates of primary production and respiration (Bernhardt et al., 2022) [(Bresnahan et al., 2023)]
Water temperature Direct impact on gas solubility, metabolic rates (primary production, respiration, methanogenesis).Warming can shift the balance towards more CO2 and CH4 release rather than uptake into biomass (Demars et al., 2011, Yvon-Durocher et al., 2011) [(Hong et al., 2021)]