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2.2 Biogeochemical Sensors of IndARC Mooring
2.2.1 Photosynthetically Active Radiation (PAR)
Photosynthetically active radiation (PAR), indicates the spectral range of solar radiation from 400 to 700 nm that photosynthetic organisms are able to use in the process of photosynthesis.
2.2.2 Fluorescence and Turbidity Sensor (FLNTUS)
This sensor uses environmental characterisation optics for determining the amount
of fluorescence and turbidity of sea water. This can effectively result in detection of
presence of biological matters in sea water.
2.2.3 Submersible Ultraviolet Nitrate Analyser (SUNA)
The SUNA V2 (Submersible Ultraviolet Nitrate Analyser) is a chemical-free UV
nitrate sensor based on the ISUS (In Situ Ultraviolet Spectroscopy) UV nitrate measurement technology developed at MBARI. With improved optics and built-in logic,
the SUNA V2 measures nitrate with high accuracy and stability over a wide range
of environmental conditions.
2.2.4 Passive Acoustic System in the Mooring
An autonomous ocean ambient noise measurement system for the Arctic region has
been designed developed and deployed by incorporating with IndArc mooring. The
objective is to record time series of ocean ambient noise data in the Arctic region to
study the glacier melting mechanisms, dynamics of the sea ice cover, movements
and oscillations of ice flow and biological noise. The system consists of a data
acquisition system with power pack enclosed in an underwater pressure casing and
hydrophones. This system was positioned at 30 m below the sea surface and
deployed as part of IndArc II in July 2015 (Thirunavukkarasu et al. 2017).
The deployed system collected the ambient noise data for 9 months from July
2015 to April 2016. During the year 2016, the system was enhanced with two hydrophones and increased sampling duration. In July 2017, the system was retrieved
with data sets for 8 months and system was redeployed with two hydrophones and
batteries with enhanced battery capacity.
In order to overcome the harsh environment prevailing the Arctic region, the
developed system has been tested for the pressure rating 10 bar at Hyperbaric
Facility, NIOT and Temperature cyclic testing with a range of +40 °C to −5 °C at
Environmental facility, NIOT. The buoyancy testing of the total system has also
been carried out at the Acoustic Test Facility, NIOT.
R. Venkatesan et al.
2.2 Biogeochemical Sensors of IndARC Mooring
2.2.1 Photosynthetically Active Radiation (PAR)
Photosynthetically active radiation (PAR), indicates the spectral range of solar radiation from 400 to 700 nm that photosynthetic organisms are able to use in the process of photosynthesis.
2.2.2 Fluorescence and Turbidity Sensor (FLNTUS)
This sensor uses environmental characterisation optics for determining the amount
of fluorescence and turbidity of sea water. This can effectively result in detection of
presence of biological matters in sea water.
2.2.3 Submersible Ultraviolet Nitrate Analyser (SUNA)
The SUNA V2 (Submersible Ultraviolet Nitrate Analyser) is a chemical-free UV
nitrate sensor based on the ISUS (In Situ Ultraviolet Spectroscopy) UV nitrate measurement technology developed at MBARI. With improved optics and built-in logic,
the SUNA V2 measures nitrate with high accuracy and stability over a wide range
of environmental conditions.
2.2.4 Passive Acoustic System in the Mooring
An autonomous ocean ambient noise measurement system for the Arctic region has
been designed developed and deployed by incorporating with IndArc mooring. The
objective is to record time series of ocean ambient noise data in the Arctic region to
study the glacier melting mechanisms, dynamics of the sea ice cover, movements
and oscillations of ice flow and biological noise. The system consists of a data
acquisition system with power pack enclosed in an underwater pressure casing and
hydrophones. This system was positioned at 30 m below the sea surface and
deployed as part of IndArc II in July 2015 (Thirunavukkarasu et al. 2017).
The deployed system collected the ambient noise data for 9 months from July
2015 to April 2016. During the year 2016, the system was enhanced with two hydrophones and increased sampling duration. In July 2017, the system was retrieved
with data sets for 8 months and system was redeployed with two hydrophones and
batteries with enhanced battery capacity.
In order to overcome the harsh environment prevailing the Arctic region, the
developed system has been tested for the pressure rating 10 bar at Hyperbaric
Facility, NIOT and Temperature cyclic testing with a range of +40 °C to −5 °C at
Environmental facility, NIOT. The buoyancy testing of the total system has also
been carried out at the Acoustic Test Facility, NIOT.
R. Venkatesan et al.