Blog: Radially Aligned Linear Photosynthetron - 9 March

9 March 2018

In the back of Karl Safi’s lab, where we found him working in the semi-dark, is a very futuristic looking piece of kit called the Radially Aligned Linear Photosynthetron (RALPH).

Sadie Mills, NIWA

Attribution, Non-Commercial, No Derivative Work

RALPH is used to measure surface primary production in water collected by the CTD deployments at up to six selected depths.

Each chamber in the RALPH contains 12 small bottles that are exposed to different light regimes the further they are from the light in the middle of the machine. Each chamber has samples from a different water depth in it. Karl uses C₁₄, a radioactive tracer for the fixation of carbon (uptake of CO₂) by phytoplankton in the water samples. The RALPH system gives Photosynthetic Irradiance curves, which allow the microbial team to compare to the instantaneous results coming from Andres’s FRRF instrument (the Fast Repetition Rate fluorometer) that we mentioned in an earlier blog (15^th Feb).

Sadie Mills, NIWA

Attribution, Non-Commercial, No Derivative Work