A new frontier for river network biogeochemical studies: going with the flow; with an example from the upper Colorado River
Abstract
Most water quality studies to date are conducted in an Eulerian fashion in which sensors are deployed or sampling is conducted at fixed sites, or in a synoptic fashion, in which many measurements are made or samples collected over a short period of time to create spatial snapshots of a stream/river reach or network. However, there has been significant interest in approaching water quality studies from a Lagrangian perspective, in which the evolution of a parcel of water as it moves downstream is quantified. While there remain some limitations to the number and frequency of parcel tracking that can be completed, the intellectual advance and goal of simulating water quality evolution down networks is a compelling goal that would overcome limitations of current conceptual and numerical models. We conducted a Lagrangian data collection campaign on 346 km of the upper Colorado River in July 2018 with fixed water quality data collection at 5 locations along this segment. We measured pH, electrical conductivity, fluorescent dissolved organic matter, turbidity, temperature, dissolved oxygen, dissolved nitrate, and dissolved CO2. We also collected grab samples for nutrient, major element and isotope chemistry. We demonstrate that while broad spatial patterns from the Lagrangian data set corroborate the Eulerian data sets (increasing water temperature, dissolved nitrate, turbidity, and electrical conductivity), it also allows us to identify specific locations of biogeochemical changes to the river due to either tributary or diffuse inflows associated with local land management practices. Further, we are able to estimate rates of metabolism and nutrient retention along the river network as well. As a scientific community, we are indeed pushing the boundaries of new conceptual models of biogeochemical cycling in river networks with these new approaches.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B41B..09G
- Keywords:
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- 0498 General or miscellaneous;
- BIOGEOSCIENCESDE: 0499 New fields (not classifiable under other headings);
- BIOGEOSCIENCES