scholarly journals Underwater Hyperspectral Imaging (UHI): A Review of Systems and Applications for Proximal Seafloor Ecosystem Studies

2021 ◽  
Vol 13 (17) ◽  
pp. 3451
Author(s):  
Juan C. Montes-Herrera ◽  
Emiliano Cimoli ◽  
Vonda Cummings ◽  
Nicole Hill ◽  
Arko Lucieer ◽  
...  
Keyword(s):  
Hyperspectral Imaging ◽  
Spatial Scales ◽  
Marine Ecosystem ◽  
Sediment Cores ◽  
Time Lapse ◽  
Underwater Imaging ◽  
Ecosystem Monitoring ◽  
Ecosystem Research ◽  
Spatial And Temporal Scales ◽  
Functional Features

Marine ecosystem monitoring requires observations of its attributes at different spatial and temporal scales that traditional sampling methods (e.g., RGB imaging, sediment cores) struggle to efficiently provide. Proximal optical sensing methods can fill this observational gap by providing observations of, and tracking changes in, the functional features of marine ecosystems non-invasively. Underwater hyperspectral imaging (UHI) employed in proximity to the seafloor has shown a further potential to monitor pigmentation in benthic and sympagic phototrophic organisms at small spatial scales (mm–cm) and for the identification of minerals and taxa through their finely resolved spectral signatures. Despite the increasing number of studies applying UHI, a review of its applications, capabilities, and challenges for seafloor ecosystem research is overdue. In this review, we first detail how the limited band availability inherent to standard underwater cameras has led to a data analysis “bottleneck” in seafloor ecosystem research, in part due to the widespread implementation of underwater imaging platforms (e.g., remotely operated vehicles, time-lapse stations, towed cameras) that can acquire large image datasets. We discuss how hyperspectral technology brings unique opportunities to address the known limitations of RGB cameras for surveying marine environments. The review concludes by comparing how different studies harness the capacities of hyperspectral imaging, the types of methods required to validate observations, and the current challenges for accurate and replicable UHI research.

scholarly journals Marine ecosystem acoustics (MEA): quantifying processes in the sea at the spatio-temporal scales on which they occur

2014 ◽  
Vol 71 (8) ◽  
pp. 2357-2369 ◽  
Author(s):  
Olav Rune Godø ◽  
Nils Olav Handegard ◽  
Howard I. Browman ◽  
Gavin J. Macaulay ◽  
Stein Kaartvedt ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Marine Ecosystem ◽  
Single Species ◽  
Fish Stock ◽  
Temporal Scales ◽  
Flexible Tool ◽  
Ecosystem Research ◽  
Spatial And Temporal Scales ◽  
Fisheries Resources ◽  
Spatio Temporal

Abstract Sustainable management of fisheries resources requires quantitative knowledge and understanding of species distribution, abundance, and productivity-determining processes. Conventional sampling by physical capture is inconsistent with the spatial and temporal scales on which many of these processes occur. In contrast, acoustic observations can be obtained on spatial scales from centimetres to ocean basins, and temporal scales from seconds to seasons. The concept of marine ecosystem acoustics (MEA) is founded on the basic capability of acoustics to detect, classify, and quantify organisms and biological and physical heterogeneities in the water column. Acoustics observations integrate operational technologies, platforms, and models and can generate information by taxon at the relevant scales. The gaps between single-species assessment and ecosystem-based management, as well as between fisheries oceanography and ecology, are thereby bridged. The MEA concept combines state-of-the-art acoustic technology with advanced operational capabilities and tailored modelling integrated into a flexible tool for ecosystem research and monitoring. Case studies are presented to illustrate application of the MEA concept in quantification of biophysical coupling, patchiness of organisms, predator–prey interactions, and fish stock recruitment processes. Widespread implementation of MEA will have a large impact on marine monitoring and assessment practices and it is to be hoped that they also promote and facilitate interaction among disciplines within the marine sciences.

scholarly journals Wavelet-based spatial comparison technique for analysing and evaluating two-dimensional geophysical model fields

2012 ◽  
Vol 5 (1) ◽  
pp. 223-230 ◽  
Author(s):  
S. Saux Picart ◽  
M. Butenschön ◽  
J. D. Shutler
Keyword(s):  
Satellite Data ◽  
Fishery Management ◽  
Numerical Models ◽  
Spatial Scales ◽  
Marine Ecosystem ◽  
Original Method ◽  
Precipitation Forecast ◽  
Spatial And Temporal Scales ◽  
Geographical Patterns ◽  
Marine Ecosystem Model

Abstract. Complex numerical models of the Earth's environment, based around 3-D or 4-D time and space domains are routinely used for applications including climate predictions, weather forecasts, fishery management and environmental impact assessments. Quantitatively assessing the ability of these models to accurately reproduce geographical patterns at a range of spatial and temporal scales has always been a difficult problem to address. However, this is crucial if we are to rely on these models for decision making. Satellite data are potentially the only observational dataset able to cover the large spatial domains analysed by many types of geophysical models. Consequently optical wavelength satellite data is beginning to be used to evaluate model hindcast fields of terrestrial and marine environments. However, these satellite data invariably contain regions of occluded or missing data due to clouds, further complicating or impacting on any comparisons with the model. This work builds on a published methodology, that evaluates precipitation forecast using radar observations based on predefined absolute thresholds. It allows model skill to be evaluated at a range of spatial scales and rain intensities. Here we extend the original method to allow its generic application to a range of continuous and discontinuous geophysical data fields, and therefore allowing its use with optical satellite data. This is achieved through two major improvements to the original method: (i) all thresholds are determined based on the statistical distribution of the input data, so no a priori knowledge about the model fields being analysed is required and (ii) occluded data can be analysed without impacting on the metric results. The method can be used to assess a model's ability to simulate geographical patterns over a range of spatial scales. We illustrate how the method provides a compact and concise way of visualising the degree of agreement between spatial features in two datasets. The application of the new method, its handling of bias and occlusion and the advantages of the novel method are demonstrated through the analysis of model fields from a marine ecosystem model.

scholarly journals Robust, real-time and autonomous monitoring of ecosystems with an open, low-cost, networked device

2017 ◽  
Author(s):  
Sarab S. Sethi ◽  
Robert M. Ewers ◽  
Nick S. Jones ◽  
C. David L. Orme ◽  
Lorenzo Picinali
Keyword(s):  
Open Source ◽  
Real Time ◽  
Spatial Scales ◽  
Low Cost ◽  
Mobile Network ◽  
Cost Effective ◽  
Automated Analysis ◽  
Time Lapse ◽  
List Type ◽  
Ecosystem Monitoring

AbstractAutomated methods of monitoring ecosystems provide a cost-effective way to track changes in natural system’s dynamics across temporal and spatial scales. However, methods of recording and storing data captured from the field still require significant manual effort.Here we introduce an open source, inexpensive, fully autonomous ecosystem monitoring unit for capturing and remotely transmitting continuous data streams from field sites over long time-periods. We provide a modular software framework for deploying various sensors, together with implementations to demonstrate proof of concept for continuous audio monitoring and time-lapse photography.We show how our system can outperform comparable technologies for fractions of the cost, provided a local mobile network link is available. The system is robust to unreliable network signals and has been shown to function in extreme environmental conditions, such as in the tropical rainforests of Sabah, Borneo.We provide full details on how to assemble the hardware, and the open-source software. Paired with appropriate automated analysis techniques, this system could provide spatially dense, near real-time, continuous insights into ecosystem and biodiversity dynamics at a low cost.

scholarly journals Wavelet-based spatial comparison technique for analysing and evaluating two-dimensional geophysical model fields

2011 ◽  
Vol 4 (4) ◽  
pp. 3161-3183 ◽  
Author(s):  
S. Saux Picart ◽  
M. Butenschön ◽  
J. D. Shutler
Keyword(s):  
Satellite Data ◽  
Fishery Management ◽  
Numerical Models ◽  
Spatial Scales ◽  
Marine Ecosystem ◽  
Ecosystem Model ◽  
Original Method ◽  
Spatial And Temporal Scales ◽  
Geographical Patterns ◽  
Marine Ecosystem Model

Abstract. Complex numerical models of the Earth's environment, based around 3-D or 4-D time and space domains are routinely used for applications including climate predictions, weather forecasts, fishery management and environmental impact assessments. Quantitatively assessing the ability of these models to accurately reproduce geographical patterns at a range of spatial and temporal scales has always been a difficult problem to address. However, this is crucial if we are to rely on these models for decision making. Satellite data are potentially the only observational dataset able to cover the large spatial domains analysed by many types of geophysical models. Consequently optical wavelength satellite data is beginning to be used to evaluate model hindcast fields of terrestrial and marine environments. However, these satellite data invariably contain regions of occluded or missing data due to clouds, further complicating or impacting on any comparisons with the model. A methodology has recently been developed to evaluate precipitation forecasts using radar observations. It allows model skill to be evaluated at a range of spatial scales and rain intensities. Here we extend the original method to allow its generic application to a range of continuous and discontinuous geophysical data fields, and therefore allowing its use with optical satellite data. This is achieved through two major improvements to the original method: (i) all thresholds are determined based on the statistical distribution of the input data, so no a priori knowledge about the model fields being analysed is required and (ii) occluded data can be analysed without impacting on the metric results. The method can be used to assess a model's ability to simulate geographical patterns over a range of spatial scales. We illustrate how the method provides a compact and concise way of visualising the degree of agreement between spatial features in two datasets. The application of the new method, its handling of bias and occlusion and the advantages of the novel method are demonstrated through analyzing model fields from a marine ecosystem model.

scholarly journals A Comparison between One-Step and Two-Step Nesting Strategy in the Dynamical Downscaling of Regional Climate Model COSMO-CLM at 2.2 km Driven by ERA5 Reanalysis

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 260
Author(s):  
Mario Raffa ◽  
Alfredo Reder ◽  
Marianna Adinolfi ◽  
Paola Mercogliano
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Spatial Scales ◽  
Regional Climate ◽  
Weather Forecast ◽  
Medium Range Weather Forecast ◽  
Spatial And Temporal Scales ◽  
Starting Point ◽  
One Step

Recently, the European Centre for Medium Range Weather Forecast (ECMWF) has released a new generation of reanalysis, acknowledged as ERA5, representing at the present the most plausible picture for the current climate. Although ERA5 enhancements, in some cases, its coarse spatial resolution (~31 km) could still discourage a direct use of precipitation fields. Such a gap could be faced dynamically downscaling ERA5 at convection permitting scale (resolution < 4 km). On this regard, the selection of the most appropriate nesting strategy (direct one-step against nested two-step) represents a pivotal issue for saving time and computational resources. Two questions may be raised within this context: (i) may the dynamical downscaling of ERA5 accurately represents past precipitation patterns? and (ii) at what extent may the direct nesting strategy performances be adequately for this scope? This work addresses these questions evaluating two ERA5-driven experiments at ~2.2 km grid spacing over part of the central Europe, run using the regional climate model COSMO-CLM with different nesting strategies, for the period 2007–2011. Precipitation data are analysed at different temporal and spatial scales with respect to gridded observational datasets (i.e., E-OBS and RADKLIM-RW) and existing reanalysis products (i.e., ERA5-Land and UERRA). The present work demonstrates that the one-step experiment tendentially outperforms the two-step one when there is no spectral nudging, providing results at different spatial and temporal scales in line with the other existing reanalysis products. However, the results can be highly model and event dependent as some different aspects might need to be considered (i.e., the nesting strategies) during the configuration phase of the climate experiments. For this reason, a clear and consolidated recommendation on this topic cannot be stated. Such a level of confidence could be achieved in future works by increasing the number of cities and events analysed. Nevertheless, these promising results represent a starting point for the optimal experimental configuration assessment, in the frame of future climate studies.

scholarly journals Habitat heterogeneity drives scale-dependent biodiversity loss in a temperate marine ecosystem

2018 ◽  
Author(s):  
Samuel Starko ◽  
Lauren Bailey ◽  
Elandra Creviston ◽  
Katelyn James ◽  
Alison Warren ◽  
...  
Keyword(s):  
Habitat Heterogeneity ◽  
Spatial Scales ◽  
Marine Ecosystem ◽  
Habitat Type ◽  
Extreme Temperature ◽  
Biodiversity Loss ◽  
Community Diversity ◽  
Diversity Loss ◽  
Biological Responses ◽  
Local Wave

AbstractBiodiversity loss is driven by interacting factors operating at different spatial scales. Yet, there remains uncertainty as to how fine-scale environmental conditions mediate biological responses to broad-scale stressors. We surveyed mid-latitude kelp bed habitats to determine whether local habitat heterogeneity has mediated changes in community diversity after more than two decades of extreme temperature events, most notably the 2013-2016 heat wave. Local wave exposure conditions were key in determining responses, with some habitats remaining stable and others experiencing near complete diversity loss, leading to local declines without regional extinctions. Wave-sheltered shores, which saw the largest declines, are a very common habitat type in the Northeast Pacific and may be especially sensitive to climate-related losses in kelp diversity and abundance. Our findings highlight how local gradients can interact with global drivers to facilitate diversity loss and demonstrate how incorporating differences between habitat patches can be essential to capturing scale-dependent biodiversity loss across the landscape.

scholarly journals Quantifying year-round nocturnal bird migration with a fluid dynamics model

2021 ◽  
Vol 18 (179) ◽  
pp. 20210194
Author(s):  
Raphaël Nussbaumer ◽  
Silke Bauer ◽  
Lionel Benoit ◽  
Grégoire Mariethoz ◽  
Felix Liechti ◽  
...  
Keyword(s):  
Western Europe ◽  
Bird Migration ◽  
Spatial Scales ◽  
Spatial And Temporal Scales ◽  
Bird Density ◽  
Radar Network ◽  
Seasonal Flow ◽  
Single Night ◽  
Nocturnal Bird Migration ◽  
Migrating Birds

To understand the influence of biomass flows on ecosystems, we need to characterize and quantify migrations at various spatial and temporal scales. Representing the movements of migrating birds as a fluid, we applied a flow model to bird density and velocity maps retrieved from the European weather radar network, covering almost a year. We quantified how many birds take-off, fly, and land across Western Europe to (1) track bird migration waves between nights, (2) cumulate the number of birds on the ground and (3) quantify the seasonal flow into and out of the study area through several regional transects. Our results identified several migration waves that crossed the study area in 4 days only and included up to 188 million (M) birds that took-off in a single night. In spring, we estimated that 494 M birds entered the study area, 251 M left it, and 243 M birds remained within the study area. In autumn, 314 M birds entered the study area while 858 M left it. In addition to identifying fundamental quantities, our study highlights the potential of combining interdisciplinary data and methods to elucidate the dynamics of avian migration from nightly to yearly time scales and from regional to continental spatial scales.

scholarly journals Ideas and perspectives: Ushering the Indian Ocean into the UN Decade of Ocean Science for Sustainable Development (UNDOSSD) through marine ecosystem research and operational services – an early career's take

2021 ◽  
Vol 18 (12) ◽  
pp. 3631-3635
Author(s):  
Kumar Nimit
Keyword(s):  
Indian Ocean ◽  
Emerging Economies ◽  
Marine Ecosystem ◽  
Ongoing Research ◽  
Ecosystem Research ◽  
Ocean Science ◽  
Breathing Apparatus ◽  
The Indian Ocean ◽  
By Catch ◽  
Operational Service

Abstract. The Indian Ocean Rim hosts many of the world's underdeveloped and emerging economies that depend on the ocean resources for the livelihoods of the populations of millions. Operational ocean information services cater to the requirements of managers and end-users to efficiently harness those resources and to ensure safety. Fishery information is not the only operational service that will be needed to empower such communities in the coming decades. Coral bleaching alerts, SCUBA (self-contained underwater breathing apparatus)-assisting advisories, conservation or ecotourism assisting services (e.g. TurtleWatch or WhaleWatch), poaching and/or by-catch reduction support and jellyfish, micro-plastic and oil spill watching to name a few, but not an exhaustive list, of the services that are needed operationally. This paper outlines the existing tools and explores the ongoing research that has potential to convert the findings into operational services in near- to midterm.

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