Mission & Project Info | NOAA’s Aquarius Undersea Laboratory
Mission Blog

Hi Ron.  I wish great success with your studies.

1) What instrumentation are you using for your in-situ studies?

Ron, to address our project objectives, we have assembled a diverse team of marine geochemists, chemists, ecologists and fluid dynamics experts to examine how the metabolic activity of sponges changes the chemistry of reef waters.  We are using a suite of in situ instruments, several of which are prototype instruments with the ability to make very precise chemical measurements with short sampling intervals over long deployments.  Below I have listed several of the instruments current collecting data on Conch Reef.

Tethys submersible membrane inlet mass spectrometer – developed by Rich Camilli at Woods Hole Oceanographic Institution in collaboration with Monitor Instruments with funding from various federal science agencies, including NSF and NOPP.  Working with Prof. Chris Martens, myself and several UNC graduate students, we are using this instrument to make exceptional precise concentration measurements of dissolved gases (e.g., nitrogen, oxygen, carbon dioxide, argon) and small volatile organics. This instrument cannot only measure the concentrations of these substances, but also their isotopic makeup. This allows us to use isotopically labeled tracers to identify, in real-time, the metabolic pathways being used by the various reef organisms.

SEAS in situ instruments developed by USF and SRI.  These instruments very accurately measure various dissolved nutrients, such as ammonium, nitrite, and nitrate, as well as pH.  Our collaboration with the USF and SRI team allows us to measure the contributions of sponges to nutrient cycles on coral reefs and their impacts on reef water pH.

Acoustic Doppler velocimeters – we use these instruments to continuously measure the velocity of seawater in sponge excurrent jets and the ambient currents. Combining these data with the cross-sectional area of the excurrent jets and the concentration of dissolved chemicals and particulates, we calculate the fluxes of various chemicals and organic matter moving through sponges.

Acoustic Doppler profilers – measure the speed and direction of currents at various heights above the bottom.

Laser-based Particle Image Velocimetery (PIV) – this in situ system, developed by Cal Tech scientists is being used by project scientist Dr. Jim Hench (Stanford University) to measure small-scale fluid motions in a plane positioned across sponge excurrent jets.  The ADV measure fluid motions basically at a single point in the sponge excurrent jet.

2) Have you developed your own instruments or have you adapted the usual analytical instruments to the aquatic environment?

Several of these instruments such as Tethys are based on relatively new technologies, while some of the other instruments, although based on well tested analytical methods, have undergone significant modifications to enhance sensitivity and the ability to operate in the ocean.

3) If adaptations were made, what were they (in general)?

I am not the right person to answer this question.  I would be better answered by the groups that developed the various instruments, such as Rich Camilli for Tethys, Prof. Robert Byrne”s groups at USF for SEAS instrument, etc.

Thanks for your interest and questions.

Cheers, Dr. Niels Lindquist, aquanaut