R&D and Education
Markus Diesing, Peter J. Mitchell, Eimear O’Keeffe, Giacomo O. A. Montereale Gavazzi and Tim Le Bas
Abstract
The ocean floor, its species and habitats are under pressure from various human activities. Marine spatial planning and nature conservation aim to address these threats but require sufficiently detailed and accurate maps of the distribution of seabed substrates and habitats. Benthic habitat mapping has markedly evolved as a discipline over the last decade, but important challenges remain. To test the adequacy of current data products and classification approaches, we carried out a comparative study based on a common dataset of multibeam echosounder bathymetry and backscatter data, supplemented with groundtruth observations. The task was to predict the spatial distribution of five substrate classes (coarse sediments, mixed sediments, mud, sand, and rock) in a highly heterogeneous area of the south-western continental shelf of the United Kingdom. Five different supervised classification methods were employed, and their accuracy estimated with a set of samples that were withheld. We found that all methods achieved overall accuracies of around 50%. Errors of commission and omission were acceptable for rocky substrates, but high for all sediment types. We predominantly attribute the low map accuracy regardless of mapping approach to inadequacies of the selected classification system, which is required to fit gradually changing substrate types into a rigid scheme, low discriminatory power of the available predictors, and high spatial complexity of the site relative to the positioning accuracy of the groundtruth equipment. Some of these issues might be alleviated by creating an ensemble map that aggregates the individual outputs into one map showing the modal substrate class and its associated confidence or by adopting a quantitative approach that models the spatial distribution of sediment fractions. We conclude that further incremental improvements to the collection, processing and analysis of remote sensing and sample data are required to improve map accuracy. To assess the progress in benthic habitat mapping we propose the creation of benchmark datasets.
Remote Sens. 2020, 12(20), 3398; https://doi.org/10.3390/rs12203398
Fionnbarr Moore, Connie Kelleher, Karl Brady, Charise McKeon & Ian Lawler
“RMS Lusitania, The Story of a wreck” discusses the historical, archaeological and cultural significance of one of the world’s most important shipwrecks. The book was officially launched by Minister Josepha Madigan, Department of Culture, Heritage and the Gaeltacht and Minister Sean Canney, Department of Communications, Climate Action and the Environment in the Custom House on Thursday December 5th.
Expertise from Geological Survey Ireland (GSI) and the Marine Institute (MI) in collaboration with the Underwater Archaeology Unit (UAU), National Monuments Service and the National Museum of Ireland is drawn upon and combined with contributions from independent researchers, divers and a variety of specialists to give a fresh approach to the story of this wreck. The book is dedicated to all those who lost their lives on the RMS Lusitania.
A fresh approach to the story of this wreck is documented which tells of its building, its early voyages and its part in WWI. On 7th May 1915 the RMS Lusitania had almost completed a transatlantic voyage en route from New York to Liverpool when it was torpedoed by U-20. Within 18 minutes the Lusitania sank. The torpedo struck midship on the starboard side, under the bridge or just aft of it. A second explosion followed. Of the 1,960 people on board 1,193 lives were lost. Accounts from survivors and the rescue efforts that took place are documented. Rescue boats from Kinsale, Cobh and the surrounding areas assisted. Over 100 years after the event the question still remains as to what caused the second explosion.
The wreck of the Lusitania lies 11.5 nautical miles off the Old Head of Kinsale in a water depth of 93m. Diving and salvage became part of the history of this wreck since its sinking. In 1995 an Underwater Heritage Order was placed on the wreck by the then Minister for Arts, Culture and Gealtacht Michael D. Higgins to ensure its protection and preservation. The role of the UAU is to ensure its continued protection. The INFOMAR project has worked closely with the UAU in carrying out multiple surveys of the wreck since 2002 to assist in its monitoring. While it is slowly collapsing the bow of the wreck is still proud of the seabed and structural elements of the wreck are still clearly visible.
The book is a collaborative effort by the Department of Culture, Heritage and the Gaeltacht and the Department of Communications, Climate Action and Environment.
The book is on sale now both online and in bookshops nationwide priced at €20. Get your copy here.
