Development and Validation of a Deep-Sea Chemiluminescent Sensor for Measuring Reactive Intermediates

Lina Taenzer1, Kalina C Grabb1, Jason Kapit2, Scott D. Wankel3, William Pardis4 and Colleen Hansel5, (1)Massachusetts Institute of Technology, EAPS, Cambridge, MA, United States, (2)WHOI, Department of Applied Ocean Physics & Engineering, Woods Hole, MA, United States, (3)Woods Hole Oceanographic Institution, Marine Chemistry & Geochemistry, Woods Hole, MA, United States, (4)WHOI, Department of Applied Ocean Physics and Engineering, Woods Hole, United States, (5)Woods Hole Oceanographic Institution, Woods Hole, MA, United States
Reactive chemical species, of both chemical and biological origin, are emerging as important players in the biogeochemistry and health of the ocean. Due to their rapid production and decay, these reactive compounds are short-lived and typically in low concentration; yet, they have a disproportionately large influence on the surrounding geochemical and biological environment. In fact, there is an emerging recognition that these short-lived reactive species may even be essential to the overall efficiency of other major element cycles. The intrinsic difficulty in measuring short-lived species has been a crippling constraint on quantification of these important chemicals in the ocean, and has thereby limited the ability to predict their role in biogeochemical cycling, microbial community dynamics, and ecosystem function. Accordingly, here we present the development and construction of a submersible in situ chemiluminescent analyzer that will enable novel and essential measurements of key reactive chemicals in the ocean, including the reactive oxygen species (ROS) superoxide – the focus here for sensor development and validation. The stability, precision, and accuracy of SOLARIS was rigorously examined and confirmed in laboratory tests. SOLARIS also passed pressure testing to a depth of 6000 m, making it certified to dive on HOV Alvin to depths of 4000 m. Following lab validation, SOLARIS was deployed to make the first deep sea in situ superoxide measurements within the ocean. SOLARIS was configured in both a rosette-mounted “pelagic mode” for measuring superoxide within the water column and in a “benthic mode” on HOV Alvin to measure extracellular superoxide levels associated with deep-sea corals at Davidson Seamount in the Monterey Bay National Marine Sanctuary. Through the development and continued design refinement of SOLARIS we will gain new insight into the concentrations and distributions of ROS, and other reactive intermediates within the ocean.