Underwater hyperspectral imagery to create biogeochemical maps of seafloor properties

Johnsen, Geir; Volent, Zsolt; Dierssen, Heidi M.; Pettersen, Ragnhild; Ardelan, Murat Van; Søreide, Fredrik; Fearns, Peter; Ludvigsen, Martin; Moline, Mark A.

doi:10.1533/9780857093523.3.508

Cited by 59 publications

(104 citation statements)

References 53 publications

(62 reference statements)

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“…The relationship between integrated reflectance and symbiont concentration may prove useful to assess or monitor reef condition and the potential for bleaching. Such algorithms may be implemented using hyperspectral sensors from airborne platforms like the Portable Remote Imaging Spectrometer (PRISM) [1,38], proposed future satellite sensors, and through the use of underwater hyperspectral imagers [32,33,47,48]. However, the implementation of the algorithms will be complicated by the effects of the intervening water column, sea-surface, and atmosphere, as well as the spectral and spatial resolution of the sensor itself [24,35].…”

Section: Conclusion and Outlook For Remote Sensingmentioning

confidence: 99%

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

et al. 2016

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Spectral reflectance patterns of corals are driven largely by the pigments of photosynthetic symbionts within the host cnidarian. The warm inshore bays and cooler offshore reefs of Palau share a variety of coral species with differing endosymbiotic dinoflagellates (genus: Symbiodinium), with the thermally tolerant Symbiodinium trenchii (S. trenchii) (= type D1a or D1-4) predominating under the elevated temperature regimes inshore, and primarily Clade C types in the cooler reefs offshore. Spectral reflectance of two species of stony coral, Cyphastrea serailia (C. serailia) and Pachyseris rugosa (P. rugosa), from both inshore and offshore locations shared multiple features both between sites and to similar global data from other studies. No clear reflectance features were evident which might serve as markers of thermally tolerant S. trenchii symbionts compared to the same species of coral with different symbionts. Reflectance from C. serailia colonies from inshore had a fluorescence peak at approximately 500 nm which was absent from offshore animals. Integrated reflectance across visible wavelengths had an inverse correlation to symbiont cell density and could be used as a relative indicator of the symbiont abundance for each type of coral. As hypothesized, coral colonies from offshore with Clade C symbionts showed a greater response to experimental heating, manifested as decreased symbiont density and increased reflectance or "bleaching" than their inshore counterparts with S. trenchii. Although no unique spectral features were found to distinguish species of symbiont, spectral differences related to the abundance of symbionts could prove useful in field and remote sensing studies.

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Section: Conclusion and Outlook For Remote Sensingmentioning

confidence: 99%

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

et al. 2016

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“…The concept shown here was a low areal coverage, high-resolution instrument with coverage comparable to optical cameras. The information content of the imagery will however be far more extensive (see details in Johnsen et al, 2013). Hyperspectral imaging has been mainly used for airborne applications.…”

Section: Discussionmentioning

confidence: 99%

“…Prelimi-nary data review suggests a potential for archaeological applications of the UHI (e.g., detection, mapping, and monitoring of underwater cultural heritage). In Johnsen et al (2013), the authors demonstrate spectral discrimination of sediments, rust, and paint, which are common substances in historical sites.…”

Section: Figurementioning

confidence: 99%

“…The species-specific optical fingerprints of the marine organisms have been the basis for UHI-based classification. The carotenoid astaxanthin, bonded to species-specific proteins (Elde et al, 2012;Pettersen et al, 2013), is the basis for the species-specific fingerprints from UHI (for details, see Johnsen et al, 2013). The figure shows an UHI-based image of "medium" spectral and spatial resolution.…”

Section: Tautramentioning

confidence: 99%

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Scientific Operations Combining ROV and AUV in the Trondheim Fjord

Ludvigsen¹,

Johnsen²,

Sørensen³

et al. 2014

mar technol soc j

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A B S T R A C TThis paper describes an autonomous underwater vehicle (AUV) and a remotely operated vehicle (ROV) complementing each other on a scientific cruise in the Trondheim Fjord (Norway). The Norwegian University of Science and Technology Applied Underwater Robotics-Laboratory and the Norwegian Defense Research Establishment mobilized for a collaborative cruise with an ROV equipped with video camera, dynamic positioning system, still camera for photographic mosaic, underwater hyperspectral imager (UHI) and inertial measurement unit, and the AUV Hugin HUS with synthetic aperture sonar (SAS) and still camera as main instruments. A multidisciplinary approach was used to set up the operations for using ROV, AUV, SAS, and UHI to document archaeological and biological sites. The cruise was run as an integrated operation processing data online and using collected data actively in the cruise planning and replanning.The AUV presented unparalleled area coverage capacity for mapping and search, while the ROV provided detailed information from the sites. During the cruise, approximately 20 km 2 were mapped with high-resolution sensors, and the data were ground-truthed using the ROV. These data provided new information and insight of both biological and archaeological sites.

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“…48 The Underwater Hyperspectral Imager (UHI) used in the present work represents a 49 new system for identification, mapping and monitoring of objects of interest (OOI) at 50 the seabed [25][26][27]. Underwater hyperspectral imaging is constrained to the visible part 51 of the spectrum, as both ultra violet and infrared radiation is attenuated in water [28].…”

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confidence: 99%

Underwater hyperspectral classification of deep sea corals exposed to 2-methylnaphthalene

Letnes

Hansen

Sandvik

et al. 2017

Preprint

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Tropical corals are routinely monitored from satellite and aeroplane using remote sensing techniques, revealing the health of coral reefs. Notably, coral bleaching is continuously monitored using multi-or hyperspectral imagery from satellites and aeroplanes. For deep-water corals, however, no established remote sensing technique exists, and for this reason, much less is known about the status of their habitats over time. The purpose of the present work was to evaluate the use of underwater hyperspectral imaging to detect changes in health status of both orange and white color morphs of the coral species L. pertusa. In this study, we examine the feasibility of similar ecosystem health monitoring by the use of underwater hyperspectral imagery. A total of 66 coral samples were exposed to 2-methylnaphthalene concentrations from 0 mg L −1 to 3.5 mg L −1 , resulting in corals of varying health condition. By use of a machine learning model for classification of reflectance spectra, we were able to classify exposed corals according to lethal concentration (LC) levels LC5 (5 % mortality) and LC25 (25 % mortality). This is a first step in developing a remote sensing technique able to assess environmental impact on deep-water coral habitats over larger areas underwater.

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Underwater hyperspectral imagery to create biogeochemical maps of seafloor properties

Cited by 59 publications

References 53 publications

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

Scientific Operations Combining ROV and AUV in the Trondheim Fjord

Underwater hyperspectral classification of deep sea corals exposed to 2-methylnaphthalene

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