Jeffrey W. Kaeli

No barrier to emergence of bathyal king crabs on the Antarctic shelf

Significance For tens of millions of years, cold conditions have excluded shell-crushing fish and crustaceans from the continental shelf surrounding Antarctica. Rapid warming is now allowing predatory crustaceans to return. Our study of the continental slope off the western Antarctic Peninsula showed that abundant, predatory king crabs comprise a reproductively viable population at 841- to 2,266-m depth. Depth profiles of temperature, salinity, habitat structure, food availability, and predators indicate that there are no barriers to prevent king crabs from moving upward onto the outer shelf at 400–550 m. A cold-water barrier above 200 m could be breached within the next few decades. Emergence of king crabs on the shelf could have catastrophic consequences for the unique seafloor communities of Antarctica. Cold-water conditions have excluded durophagous (skeleton-breaking) predators from the Antarctic seafloor for millions of years. Rapidly warming seas off the western Antarctic Peninsula could now facilitate their return to the continental shelf, with profound consequences for the endemic fauna. Among the likely first arrivals are king crabs (Lithodidae), which were discovered recently on the adjacent continental slope. During the austral summer of 2010‒2011, we used underwater imagery to survey a slope-dwelling population of the lithodid Paralomis birsteini off Marguerite Bay, western Antarctic Peninsula for environmental or trophic impediments to shoreward expansion. The population density averaged ∼4.5 individuals × 1,000 m−2 within a depth range of 1,100‒1,500 m (overall observed depth range 841–2,266 m). Images of juveniles, discarded molts, and precopulatory behavior, as well as gravid females in a trapping study, suggested a reproductively viable population on the slope. At the time of the survey, there was no thermal barrier to prevent the lithodids from expanding upward and emerging on the outer shelf (400- to 550-m depth); however, near-surface temperatures remained too cold for them to survive in inner-shelf and coastal environments (<200 m). Ambient salinity, composition of the substrate, and the depth distribution of potential predators likewise indicated no barriers to expansion of lithodids onto the outer shelf. Primary food resources for lithodids—echinoderms and mollusks—were abundant on the upper slope (550–800 m) and outer shelf. As sea temperatures continue to rise, lithodids will likely play an increasingly important role in the trophic structure of subtidal communities closer to shore.

Photographic survey of benthos provides insights into the Antarctic fish fauna from the Marguerite Bay slope and the Amundsen Sea

Abstract We reviewed photographic images of fishes from depths of 381–2282 m in Marguerite Bay and 405–2007 m in the Amundsen Sea. Marguerite Bay fishes were 33% notothenioids and 67% non-notothenioids. Channichthyids (47%) and nototheniids (44%) were the most abundant notothenioids. The deep-living channichthyid Chionobathyscus dewitti (74%) and the nototheniid genus Trematomus (66%) were the most abundant taxa within these two families. The most abundant non-notothenioids were the macrourid Macrourus whitsoni (72%) and zoarcids (18%). Amundsen Sea fishes were 87% notothenioids and 13% non-notothenioids, the latter exclusively Macrourus whitsoni. Bathydraconids (38%) and artedidraconids (30%) were the most abundant notothenioids. We observed that Macrourus whitsoni was benthopelagic and benthic and infested by large ectoparasitic copepods. Juvenile (42 cm) Dissostichus mawsoni was not neutrally buoyant and resided on the substrate at 1277 m. Lepidonotothen squamifrons was seen near and on nests of eggs in early December. A Pogonophryne sp. from 2127 m was not a member of the deep-living unspotted P. albipinna group. Chionobathyscus dewitti inhabited the water column as well as the substrate. The pelagic zoarcid Melanostigma gelatinosum was documented in the water column a few metres above the substrate. The zoogeographic character of the Marguerite Bay fauna was West Antarctic or low-Antarctic and the Amundsen Sea was East Antarctic or high-Antarctic.

Improving color correction for underwater image surveys

We propose and implement a novel method of estimating attenuation coefficients and a strobe beam pattern using sequences of overlapping underwater color images and acoustic ranges from a Dopper Velocity Log (DVL). These values are used to correct the images for color and illumination artifacts with the goal of more consistent color correction for input into classification algorithms.

Computational strategies for understanding underwater optical image datasets

Thesis: Ph. D. in Mechanical and Oceanographic Engineering, Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 2013.

An Automated Morphological Image Processing Based Methodology for Quantifying Coral Cover in Deeper-Reef Zones

With the advent of new robotic technologies such as AUVs, a number of end user communities are being inundated with large amounts of data. The traditional techniques of manually counting and sorting out organisms in individual images are just not scaleable to the large datasets that are now being acquired. This paper examines the use of morphological image operators in the automated analysis of imagery for studies associated with coral reef ecology. We propose a texture-based algorithm to segment out areas of coral cover in these images. Results show percent cover values competitive with the existing human methods

Perspectives in visual imaging for marine biology and ecology: from acquisition to understanding

1National Oceanography Centre, European Way, Southampton, United Kingdom Email: Jennifer.Durden@noc.soton.ac.uk 2Ocean and Earth Science, University of Southampton, National Oceanography Centre Southampton, European Way, Southampton, United Kingdom 3GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany 4CSIRO (Oceans & Atmosphere Flagship), Hobart, Australia 5Australian Centre for Field Robotics, University of Sydney, Sydney, Australia 6Girona University, Girona, Spain 7Life Sciences Department, Natural History Museum, Cromwell Road, London, United Kingdom 8Monterey Bay Aquarium Research Institute, Moss Landing, California, USA 9Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA 10Japan Agency for MarineEarth Science and Technology, Natsushimacho, Yokosuka, Japan 11Biodata Mining Group, Faculty of Technology, Bielefeld University, Bielefeld, Germany 12Geoscience Australia, Symonston, Australia

Visual summaries for low-bandwidth semantic mapping with autonomous underwater vehicles

A fundamental problem in autonomous underwater robotics is the high latency between the capture of image data and the time at which operators are able to gain a visual understanding of the survey environment. Typical missions can generate imagery at rates orders of magnitude greater than highly compressed images can be transmitted acoustically, delaying that understanding until after the robot has been recovered and the data analyzed. We present modifications to state-of-the-art online visual summary techniques that enable an autonomous robot to select representative images to be compressed and transmitted acoustically to the surface ship. These transmitted images then serve as the basis for a semantic map which, combined with scalar navigation data and classification masks, can provide an operator with a visual understanding of the survey environment while a mission is still underway.

Advances in Platforms and Algorithms for High Resolution Mapping in the Marine Environment

A confluence of technologies is changing the manner in which we approach the use of Autonomous Underwater Vehicles (AUVs) in the marine environment. In this paper we review the role of several of these technologies and the way interactions between them will now enable the use of adaptive methodologies for mapping and exploring the underwater environment. We focus primarily on imaging sensors but these methodologies are widely applicable for other types of sensing modalities as well. We look at the role of acoustic telemetry, multi-hop underwater data transmission, in-situ machine learning techniques, and mapping in highly dynamic environments such as under sea ice. In addition, we discuss the role of “hobby” robotics for surface and aerial vehicles in the marine environment.

Development of a propeller driven long range autonomous underwater vehicle (LRAUV) for under-ice mapping of oil spills and environmental hazards: An Arctic Domain Center of Awareness project (ADAC)

The increasing level of commercial marine activity in high latitudes creates an ever growing risk of oil spills. Even in logistically accessible, ice-free oceans, characterizing the extent and nature of a spill can be challenging as highlighted by the Deepwater Horizon incident. We propose to develop an AUV-based approach inspired by an existing small, long-range system, called the Tethys Long-Range AUV (LRAUV), in order to support the Arctic Doman Awareness Center (ADAC) for spill preparedness.

Real-time anomaly detection in side-scan sonar imagery for adaptive AUV missions

Autonomous Underwater Vehicle (AUV) operations are inherently bandwidth limited but increasingly data intensive. This leads to large latencies between the capture of image data and the time at which operators are able to make informed decisions using the results of a survey. As AUV endurance and reliability continue to improve, there is a greater need for real-time data processing to inform on-board adaptive mission planning. In this paper, we present an anomaly detection framework based on saliency and rarity and demonstrate it using existing side-scan sonar datasets collected by an AUV. Salient regions are first identified using a novel method with analogies to keypoint detection in traditional image processing. Models of these regions are then learned to determine rarity using an online approach for real-time use during a mission. The algorithm we present will be implemented in field trials later this year. This approach to adaptive mission planning enables an AUV to both resurvey anomalies at higher resolutions and selectively transmit imagery for operator analysis and feedback within the scope of a single deployment.