Hourly In Situ Nitrate on a Coastal Mooring: A 15-Year Record and Insights into New Production

In situ Determination of Nitrate and Hydrogen Sulfide in the Baltic Sea Using an Ultraviolet Spectrophotometer

“…Maximum deviations were found in the bottom water and were only 6% (TF200), 3% (TF245), and 6% (TF286). It should be noted here, that pressure effects on bromide absorbance were neglected in our study because we have worked in shallow waters, but should be taken into account at higher pressures (Sakamoto et al, 2017).…”

“…However, with the help of in situ sensors, it is possible to reduce the working time as well as contamination and altering of the sample. In addition, in situ sensors have a small size, low weight and relatively low energy consumption, and therefore are suitable for being deployed on moorings (Collins et al, 2013;Sakamoto et al, 2017), floats (Johnson et al, 2013(Johnson et al, , 2017D'Ortenzio et al, 2014;Pasqueron de Fommervault et al, 2015), towed vehicles (Pidcock et al, 2010) or autonomous underwater vehicles (Johnson and Needoba, 2008). In situ sensors are thus helping to bridge the gap between large-scale but non-specific remote observations of satellites limited to the surface waters and highly sophisticated and specific laboratory analysis from discrete water samples (Zielinski et al, 2009).…”

Climate Variability and Change: Response of a Coastal Ocean Ecosystem

“…The mooring data are of high temporal resolution (10 minutes to 3 hours). Originally modeled on the ATLAS moorings of the Tropical Atmosphere Ocean (TAO) array (https://www.pmel.noaa.gov/gtmba), M1 has been extensively modified and carries suites of meteorological and oceanographic sensors (Chavez et al, 1997), including ocean and atmosphere pCO 2 ( Figure B1-1), the in situ ultraviolet spectrophotometer (ISUS) nitrate sensor (Sakamoto et al, 2017, in this issue), and optical sensors (fluorescence, backscatter, downwelling irradiance, and upwelling radiance). M1 serves as a source of environmental data for the local and global communities and also as a platform for technology development and testing (Friederich et al, 1995;Johnson and Coletti, 2002;Johnson et al, 2006).…”

Toward a Harmonization for Using in situ Nutrient Sensors in the Marine Environment

“…Currently nitrate is the only macronutrient that can be quantified using optical measurement principals. A broad spectral range is required to accurately resolve absorption spectra in complex media such as seawater as the detection of nitrate is based on deconvolution of absorbance spectra that include halogenates such as bromide (Johnson and Coletti, 2002;Frank et al, 2014;Sakamoto et al, 2017). Several commercially available instruments and one prototype can be found: ISUS/SUNA (Seabird Scientific), ProPS/OPUS (TRIOS), Spectro::lyser (S::can Measuring Systems) and SUV-6 (Finch et al, 1998;Pidcock et al, 2010).…”

“…Signal drift due to biofouling on the optical measuring window has been observed especially in coastal waters over long deployments (Prien, 2007;Pellerin et al, 2013). UV optical sensors have been widely used on coastal platforms (Spectro::lyser, Etheridge et al, 2014), moorings (OPUS and SUNA; Collins et al, 2013;Sakamoto et al, 2017) and FerryBox-systems (ProPS, Petersen et al, 2011;SUNA, Frank et al, 2014). Recently Meyer et al (2018) demonstrated that an in situ UV sensor (OPUS) has the capability to resolve vertical nitrate profiles with high frequency.…”