Automated in Situ Oxygen Profiling at Aquatic-Terrestrial Interfaces

Area of Science:

• Environmental Science
• Geochemistry
• Sensor Technology

Background:

• Accurate in situ oxygen sensing is crucial for understanding soil and sediment processes.
• Existing methods often lack the resolution or duration for capturing dynamic oxygen variability.
• Optical sensing offers a promising avenue for high-resolution, long-term monitoring.

Purpose of the Study:

• To develop and demonstrate a miniaturized Distributed Oxygen Sensor (mDOS) for long-term in situ oxygen profiling.
• To capture fine-scale spatial and temporal oxygen dynamics in soil and sediment.
• To investigate the relationship between oxygen dynamics and hydrological conditions.

Main Methods:

• Development of a miniaturized Distributed Oxygen Sensor (mDOS) system.
• Deployment for unattended, repeated acquisition of oxygen profiles.
• High-resolution (subcentimeter) measurements up to one meter depth.
• Analysis of spatiotemporal oxygen variability under varying hydrological conditions.

Main Results:

• The mDOS system successfully acquired time series of in situ oxygen profiles with subcentimeter resolution.
• High spatial and temporal variability in oxygen dynamics was revealed.
• The sensor demonstrated applicability in capturing intra- and interday oxygen fluctuations.
• Dependencies between oxygen dynamics and hydrological conditions were estimated.

Conclusions:

• The mDOS system provides unprecedented detail on oxygen dynamics in soil and sediment.
• It is a valuable tool for understanding the coupling of hydrological and biogeochemical processes.
• Enables insights into transition zones between aquatic and terrestrial environments.