Spatial Modeling of Tsunami Vortices in the Coastal Ocean

It is important to plan for potential tsunamis during the marine spatial planning process so that land uses may be modified or defensive infrastructure may be erected. Tsunami vortices had been observed during the occurrence and propagation of tsunami waves. Actual observations during the March 2011 Japan tsunami and the Indian Ocean tsunami of December 2004 showed the formation of vortices which lasted for several hours. The Palu tsunami of September 2018 in Indonesia also showed the formation of a tsunami vortex whose centre was photographed by a pilot and appeared as a deep hole in the ocean. Several vortices with various sizes lasted for several hours after the quake and they also generated a loud roar as the giant waves inundated low-lying coastal areas. This essay attempts to describe the development of a model that can explain the formation of tsunami vortices.

The Future of Marine Spatial Planning—Perspectives from Early Career Researchers

In early 2021, the Erasmus+ knowledge flows partnership organised a session to discuss the future of marine spatial planning (MSP) at an international conference. We, a group of nine early career researchers, came together after the conference to continue the discussion: which topics should be considered in future MSP, what are the challenges, and which solutions are there to overcome these challenges? This communication shall raise awareness of the topics of climate change, ecological sustainability, blue justice, ecosystem services, and blue governance, which we identified as important for future MSP endeavours. We show the interconnectedness of the topics and argue that transdisciplinary education is required to contribute to a common understanding of MSP, which adopts an ecosystem-based approach, ensures equitable distribution of benefits, and secures ecologically sustainable development within an adaptive governance framework.

Where’s the best supermarket deal? Female Southern Rockhopper Penguins (Eudyptes chrysocome) show variable foraging areas during the guard stage at Isla de los Estados, Argentina

Understanding the spatial distribution of seabirds contributes to comprehending their ecological requirements and dispersion patterns. We studied the at-sea distribution of female Southern Rockhopper Penguins (Eudyptes chrysocome (J.R. Forster, 1781)) at Isla de los Estados colony during the early chick-rearing period. We used a clustering analysis approach to identify different groups according to the foraging trip (tracking and diving data from GPS and temperature and depth data loggers) and diet (δ15N composition on blood samples) characteristics. Foraging trips differed in duration, location, and dive depths explored. Females in clusters 1 and 3 traveled longer distances and in opposite directions (36.3 ± 21.3 and 40.3 ± 14.0 km, respectively). Females in cluster 2 fed closer to the colony (16.8 ± 7.8 km). Dives occurred in pelagic habitats. Higher δ15N values suggested a greater proportion of fish (e.g., the Fuegian sprat, Sprattus fuegensis (Jenyns, 1842)) consumption in the northern foraging areas (cluster 1). The variability observed in the spatial distribution suggests flexibility in the foraging behavior of Southern Rockhopper Penguins and availability of adequate foraging areas within the colony range during the early chick-rearing period, both important features for Southern Rockhopper Penguin population. These results contribute to understanding the use of the Southern Ocean by marine mesopredators and top predators and to the marine spatial planning in the area.

Exact Zoning Optimization Model for Marine Spatial Planning (MSP)

Marine spatial planning (MSP) has recently attracted more attention as an efficient decision support tool. MSP is a strategic and long-term process gathering multiple competing users of the ocean with the objective to simplify decisions regarding the sustainable use of marine resources. One of the challenges in MSP is to determine an optimal zone to locate a new activity while taking into account the locations of the other existing activities. Most approaches to spatial zoning are formulated as non-linear optimization models involving multiple objectives, which are usually solved using stochastic search algorithms, leading to sub-optimal solutions. In this paper, we propose to model the problem as a Multi-Objective Integer Linear Program. The model is developed for raster data and it aims at maximizing the interest of the area of the zone dedicated to the new activity while maximizing its spatial compactness. We study two resolution methods: first, a weighted-sum of the two objectives, and second, an interactive approach based on an improved augmented version of the ϵ-constraint method, AUGMECON2. To validate and study the model, we perform experiments on artificially generated data. Our experimental study shows that AUGMECON2 represents the most promising approach in terms of relevance and diversity of the solutions, compactness, and computation time.