Nutrient Analysis in Arctic Waters Using a Portable Sensing Platform

McCaul, Margaret; Magni, Paolo; Jordan, Sean; McNamara, Eoghan; Satta, Andrea; Diamond, Dermot; Ribotti, Alberto

doi:10.3389/fsens.2021.711592

Cited by 3 publications

(1 citation statement)

References 22 publications

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“…The gold-standard approaches toward nitrate and dissolved orthophosphate measurement rely on reagent-based colorimetry and have been shown to achieve nanomolar limits of detection (Murphy et al, 2021;Morgan et al, 2022). These techniques have been applied towards benchtop & portable nutrient detection platforms (McCaul et al, 2021), mixing one or several specifically crafted reagents with sample to generate a colored complex. The amount of color produced is proportional to the concentration of the selected species and can be quantified using optical techniques.…”

Section: Introductionmentioning

confidence: 99%

Two chemistries on a single lab-on-chip: Nitrate and orthophosphate sensing underwater with inlaid microfluidics

Luy

Smith²,

Grundke³

et al. 2022

Front. Sens.

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Autonomous in situ sensors are required to monitor high-frequency nutrient fluctuations in marine environments on a mass-scale. We present a submersible, dual-chemistry sensor that performs multiple colourimetric assays simultaneously on a fluid sample for multi-parameter in situ analysis. Based on a highly configurable architecture that has been successfully deployed for several multi-month periods, the sensor utilizes 10 solenoid valves, 4 syringes, 3 stepper motors, 2 LEDs, 4 photodiodes, and “inlaid” microfluidics to permit optical measurements of microliter fluid volumes. Fluid pathways are machined into a modular two-layer microfluidic lab-on-chip (LOC) fabricated from poly (methyl methacrylate) (PMMA) with two parallel inlaid optical cells of 10.4 mm and 25.4 mm path lengths (1.7 µl and 4 μl, respectively). Different LOC designs can be used to implement a wide variety of colorimetric assays. We demonstrate application of our dual-chemistry sensor towards simultaneous measurement of nitrate and dissolved orthophosphate: two nutrients fundamental to primary production. The performance of the dual-species nitrate and phosphate “NP Sensor” is characterized first in a controlled laboratory environment. Combined nutrient standards containing nitrate and phosphate concentrations ranging from 2.5 µM–100 µM NO3− and 0.25 µM–10 µM PO43− were analyzed, reporting detection limits of 97 nM NO3− and 15 nM PO43−. Calibrations were repeated under 3 fixed temperature conditions, T = 5°C, 10°C, 15°C, to determine the temperature-dependent sensitivity relations for both species needed to calculate concentrations during field deployments. Finally, an 8-day field deployment in Fish Hatchery Park, NS, Canada followed, acquiring a total of 592 nitrate and dissolved orthophosphate measurements. An on-board combined nutrient standard was measured periodically to assess the in situ accuracy of the sensor, with an average relative uncertainty of 15% across the deployment. Measured nitrate and dissolved orthophosphate levels in the river reached as high as 10 µM and 3.6 µM, respectively. Fast Fourier transform analysis suggests a strong out-of-phase relationship between measured phosphate and water level, with a shared frequency peak in both data agreeing within a 3.2% difference. This trend is due to conventional mixing at the river mouth to neighboring Bedford Basin. A spike in the measured nitrate to phosphate (N:P) ratio was also observed, synchronized to a precipitation event and indicative of runoff. The novel sensor will enable high-frequency dual-nutrient monitoring in many aquatic environments.

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Section: Introductionmentioning

confidence: 99%

Two chemistries on a single lab-on-chip: Nitrate and orthophosphate sensing underwater with inlaid microfluidics

Luy

Smith²,

Grundke³

et al. 2022

Front. Sens.

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A Study on Derivation of Meteorological Data Regression Equation for Prediction of Livestock Derived Ammonia

Yoon¹,

Yang²,

Kim³

2023

Preprint

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Understanding and mitigating global change with aquatic sensors: current challenges and future prospects

Diamond,

Relyea,

McCaul

2023

Front. Sens.

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Human activities are causing global change around the world including habitat destruction, invasive species in non-native ecosystems, overexploitation, pollution, and global climate change. While traditional monitoring has long been used to quantify and aid mitigation of global change, in-situ autonomous sensors are being increasingly used for environmental monitoring. Sensors and sensor platforms that can be deployed in developed and remote areas and allow high-frequency data collection, which is critical for parameters that exhibit important short-term dynamics on the scale of days, hours, or minutes. In this article, we discuss the benefits of in-situ autonomous sensors in aquatic ecosystems as well as the many challenges that we have experienced over many years of working with these technologies. These challenges include decisions on sensor locations, sensor types, analytical specification, sensor calibration, sensor drift, the role of environmental conditions, sensor fouling, service intervals, cost of ownership, and data QA/QC. These challenges result in important tradeoffs when making decisions regarding which sensors to deploy, particularly when a network of sensors is desired to cover a large area. We also review recent advances in designing and building chemical-sensor platforms that are allowing researchers to develop the next-generation of autonomous sensors and the power of integrating multiple sensors into a network that provides increased insight into the dynamics of water quality over space and time. In the coming years, there will be an exponential growth in data related to aquatic sensing, which will be an essential part of global efforts to monitor and mitigate global change and its adverse impacts on society.

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Nutrient Analysis in Arctic Waters Using a Portable Sensing Platform

Cited by 3 publications

References 22 publications

Two chemistries on a single lab-on-chip: Nitrate and orthophosphate sensing underwater with inlaid microfluidics

Two chemistries on a single lab-on-chip: Nitrate and orthophosphate sensing underwater with inlaid microfluidics

A Study on Derivation of Meteorological Data Regression Equation for Prediction of Livestock Derived Ammonia

Understanding and mitigating global change with aquatic sensors: current challenges and future prospects

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