Final Report Summary - SENSENET (International sensor development network) This is also uploaded as a pdf with the cover page.The main purpose of the SENSEnet Initial Training Network was to train 16 Early Stage Researchers and one Experienced Researcher in the field of marine in-situ sensor development. Each researcher conducted their research program in collaboration with the network partners. The network partners consisted of 15 universities and 2 commercial organisations from across Europe. The scientists, engineers and researchers from these partners are all leaders in the field of in-situ sensor development and commercialisation. The outcome of this Initial Training Network is a group of capable and suitably experienced young researchers equipped with the relevant skills to enable the future monitoring of our dynamic, ever changing yet fragile marine environment.In addition to ensuring that the young scientists achieved their research objectives, the network also provided workshops and field based training to give them a broad knowledge of in-situ sensors and development. They also received transferable skills training at their institutes. The researchers actively participated in meetings and conferences and collaborated with scientists both within and outside the SENSEnet project.The main areas of research have been optical sensors, long-term in-situ chemical sensors and generic sensor issues (e.g. integration, data format standardisation, communications, biofouling). In the field of optical sensors, several new and innovative in situ measuring systems (Hyperspectral Imaging, Multifiberoptode and Surface Enhanced Raman Scattering) and sensors (O2 and pCO2 optodes) have been developed. Some of these systems have already been used to make measurements that have provided new insights into aspects of the marine environment (e.g. the migration of microphytobenthos). Several innovative chemical sensors have been developed and tested in the field including microfluidic lab-on-chip devices (for seawater pH, phosphate and dissolved iron and manganese measurements) and electrochemical sensors (for sulphide, phosphate and dissolved oxygen measurements).The feasibility of an existing technique, Eddy Correlation, to sediment-water interface oxygen flux measurements in variable marine environments has been investigated and deployed while an acoustic method to quantify flow rates from gas seepages at the seafloor has been developed. Significant advances on issues that are applicable to all in situ sensors have been made, new antifouling techniques have undergone long term testing and an optical underwater communication system has been developed.The success of the network and the young researchers is evidenced by their outputs: 33 published papers (of which 17 are first author papers), 2 accepted but not yet published 1st author papers, 6 submitted papers (of which 5 are first author), 24 further papers in preparation (of which 18 are first author) and 75 conference contributions (papers & presentations).Six of the researchers have successfully defended their PhDs (one completing within 28 months of the planned 36 month fellowship), two have submitted their PhD theses and will defend them shortly. The remaining researchers are in the final stages of writing and very close to submitting.