Award: OCE-1634463

The availability of certain nutrients and trace elements (particularly dissolved iron) is known to control the growth of oceanic plants in surface waters. However, our understanding of the detailed biogeochemical processes in the ocean is limited in part by our ability to obtain sufficient data over temporal time scales. This project developed a rapid, small volume analytical technique for the determination of dissolved phosphorus at sea. An additional advantage of the small volume nature of this method is that it not only reduces the volume of the sample needed but it reduces the amount of reagent chemicals needed for the determination helping us to move towards a more "Green Chemistry" for use in future monitoring operations. We have also designed and constructed a field deployable version of this system. During the early stages of the analytical development we participated in an international collaborative oceanographic research cruise aimed at ascertaining the accuracy of current methodology, our new analytical technique showed that it was capable of achieving similar values to those of the traditional analytical methods in real time at sea. A field deployable version of this method, using battery power was successfully developed using commercially available components including a Raspberry Pi 3 control system in a weather-resistant housing and was briefly deployed in the ocean. Intellectual Merit: The first shipboard deployment of our one pump analyzer confirmed that the technique can produce phosphate data with an accuracy comparable to that of traditional continuous flow methods but with sample and reagent volumes that are 10-20 fold smaller than current methods, the new technique also uses instrumentation that is more compact and lower maintenance than traditional instrumentation. A more recently developed two pump system further confirms the advantages of flow programming and eliminates the drawback of incomplete mixing that occurs with the one pump system. Broader Impacts: The researchers have benefited from participation in an international research project that brings technologies and scientists from different institutions together creating a collaborative cohort that will outlast the specific project. A graduate student (N. Harmon) is currently completing a MS thesis describing the field deployable phosphate analyzer. This newly developed two pump methodology will be applied to other chemical assays that are of relevance to chemical oceanography such as silicate, trace metals). Last Modified: 03/02/2020 Submitted by: Mariko Hatta