Nitrate drawdown during a shelf sea spring bloom revealed using a novel microfluidic in situ chemical sensor deployed within an autonomous underwater glider

Vincent, Alexander G.; Pascal, Robin W.; Beaton, Alexander D.; Walk, John; Hopkins, Joanne E. ORCID: https://orcid.org/0000-0003-1504-3671; Woodward, E. Malcolm S.; Mowlem, Matthew; Lohan, Maeve C.. 2018 Nitrate drawdown during a shelf sea spring bloom revealed using a novel microfluidic in situ chemical sensor deployed within an autonomous underwater glider. Marine Chemistry, 205. 29-36. https://doi.org/10.1016/j.marchem.2018.07.005

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Official URL: http://dx.doi.org/10.1016/j.marchem.2018.07.005

Abstract/Summary

Here we describe, for the first time, the use of a miniaturized Lab-on-Chip (LoC) nutrient sensor deployed within an autonomous underwater vehicle (AUV; Kongsberg Seaglider) to collect high-resolution nitrate (nitrate + nitrite) data in a highly dynamic shelf sea environment. Seasonally stratified temperate shelf seas act as important carbon sinks, where primary production is controlled by the availability of nutrients such as nitrate. Spring phytoplankton blooms and sporadic mixing events can drastically modify the availability of nitrate on temporal scales from hours to days. Traditional sampling methods are unable to capture high frequency events that can be clearly observed using a wet-chemical microfluidic system deployed within a glider. We highlight firstly, an excellent agreement between the LoC and shipboard nitrate + nitrite measurements (r2 = 0.98 n = 11). Secondly, the LoC was able to observe a decrease in nitrate within the surface mixed layer from 5.74 μM (4th) to 1.42 μM (25th) during the onset of the spring bloom, whilst bottom layer concentrations remained constant (6.86 ± 0.16 μM), with an estimated analytical uncertaintly of <0.2 μM. Thirdly, the ability of an LoC sensor deployed within an AUV to accurately capture simultaneous biogeochemical and physical parameters at an enhanced resolution, on both spatial and temporal scales, improves our understanding of biogeochemical cycles within the dynamic temperate shelf sea environments.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.marchem.2018.07.005
ISSN:	03044203
Date made live:	10 Aug 2018 11:46 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/520687

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.marchem.2018.07.005

ISSN:

03044203

Date made live:

10 Aug 2018 11:46 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/520687