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Dhugal John Lindsay

Dhugal John Lindsay
Japan Agency for Marine-Earth Science and Technology (JAMSTEC) · Advanced Science-Technology Research (ASTER) Program Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star)

PhD

About

215
Publications
49,156
Reads
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2,094
Citations
Introduction
gelatinous zooplankton, in situ survey technologies, cnidarian and ctenophore taxonomy, biogeography and speciation, imaging and machine learning
Additional affiliations
April 2019 - March 2028
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Position
  • Researcher
April 2019 - present
Kitasato University
Position
  • Professor
April 2014 - March 2019
Japan Agency for Marine-Earth Science Technology
Position
  • Researcher
Education
April 1995 - July 1998
The University of Tokyo
Field of study
  • Aquatic Biology
April 1993 - March 1995
The University of Tokyo
Field of study
  • Agriculture and Life Sciences
January 1990 - December 1992
The University of Queensland
Field of study
  • Japanese Studies

Publications

Publications (215)
Article
Full-text available
In the Southern Ocean, several zooplankton taxonomic groups, euphausiids, copepods, salps and pteropods, are notable because of their biomass and abundance and their roles in maintaining food webs and ecosystem structure and function, including the provision of globally important ecosystem services. These groups are consumers of microbes, primary a...
Article
Full-text available
Freshwater jellyfish comprising the genus Craspedacusta are thought to have originated in the Yangtze River, China and have since spread to all continents except Antarctica. In this study, jellyfish were collected from Haruta-ike, an artificial pond in Chikuma City, Nagano (Japan). Medusae were identified as Craspedacusta sowerbii using morphologic...
Article
Full-text available
Quantitative imaging instruments produce a large number of images of plankton and marine snow, acquired in a controlled manner, from which the visual characteristics of individual objects and their in situ concentrations can be computed. To exploit this wealth of information, machine learning is necessary to automate tasks such as taxonomic classif...
Chapter
Gelatinous zooplankton (GZ) is a non-taxonomic term for jelly-like organisms that have a high proportion of water in body tissues. Advantages in being gelatinous include better buoyancy, transparency, larger sizes with lower carbon investment, rapid growth and body plasticity. Most GZ taxa have different pathways of asexual reproduction that may qu...
Presentation
Midwater marine environments are one of the largest ecosystems on earth. Collecting visual data of a quality from which identifications can be made is difficult due to limited survey opportunities. Often during dives, long video recordings are made, which need to be analyzed in real-time or in post processing for annotating observations. Although m...
Poster
Full-text available
The midwater is the largest continuous biome on our planet and is dominated by gelatinous zooplankton. Despite pelagic ecosystems being widely acknowledged for their ecosystem services, less than 1% of this vast habitat has been sampled. Narcomedusae are specialised in feeding on other gelatinous prey and play a key role in maintaining a well-balan...
Article
Digital holography is a useful tool to image microscopic particles. Reconstructed holograms give high-resolution shape information that can be used to identify the types of particles. However, the process of reconstructing holograms is computationally intensive and cannot easily keep up with the rate of data acquisition on low-power sensor platform...
Presentation
The deep sea is categorized as a cold-water environment, typically 4°C around 800 m depth near Japan. There are warm environments in the deep sea, including hydrothermal vents and the deep Mediterranean, Red and Sulu Seas; noted as having unique faunal communities that reflect the extraordinary environmental conditions. The Kuruse Hole, located in...
Article
Full-text available
Background: Southern Ocean ecosystems are currently experiencing increased environmental changes and anthropogenic pressures, urging scientists to report on their biodiversity and biogeography. Two major taxonomically diverse and trophically important gelatinous zooplankton groups that have, however, stayed largely understudied until now are the c...
Article
Measuring the distribution, characteristics and dynamics of marine microscale plankton and other particulate matter is essential to understand the vertical flux of elements in the marine environment. Digital holographic microscopy is a powerful approach for measuring these and studying their 3-D trajectories in a relatively large observation volume...
Article
Tracking deep ocean animals over their daily cycles will revolutionize our understanding of the largest biome on Earth.
Article
Full-text available
Hydrozoan jellyfish of the genus Blackfordia currently consist of three described species: B. manhattensis, B. virginica and B. polytentaculata. These species are distinguished by combinations of the position and shape of the gonads, the number of marginal tentacles, and the presence or absence of black pigments on the bell rim. We discovered a spe...
Article
Hyperspectral data in the near infrared range were examined for nine common types of plastic particles of 1 mm and 100-500 μm sizes on dry and wet glass fiber filters. Weaker peak intensities were detected for small particles compared to large particles, and the reflectances were weaker at longer wavelengths when the particles were measured on a we...
Article
Full-text available
The Salas y Gómez and Nazca ridges are two seamount chains of volcanic origin, which include over 110 seamounts that collectively stretch across over 2,900 km in the southeastern Pacific. Ecosystems in this region are isolated by the Atacama Trench, the Humboldt Current System, and an extreme oxygen minimum zone. This isolation has produced a uniqu...
Article
Full-text available
Turbidity currents are the main drivers behind the transportation of terrestrial sediments to the deep sea, and turbidite deposits from such currents have been widely used in geological studies. Nevertheless, the contribution of turbidity currents to vertical displacement of seawater has rarely been discussed. This is partly because until recently,...
Article
Full-text available
The unusual holopelagic annelid Poeobius meseres Heath, 1930 (Flabelligeridae) was first collected from Monterey Bay, California and has been subsequently recorded across the northern Pacific from Japan to the Gulf of California. Rare occurrences in the eastern tropical Pacific have extended as far as 7° S off Peru. Using molecular phylogenetic ana...
Conference Paper
p>A novel technique to analyse deep-sea particles using digital holography (DH) and Raman spectroscopy (RS) is currently being developed. Since RS requires long measurement periods to provide reliable results in water, a flow control system is necessary to trap particles in the instrument. One way in which this can be achieved is to control the flo...
Article
Full-text available
深海性クラゲは非常に多様であるが、その全貌を把握するためには遺伝子学的なアプローチに加え、新たな採集方法の開発や深海の現場における最新撮影テクノロジーの応用が必要である。映像調査の場合には、形態が把握できるだけでなく、生物の相互作用や詳細スケールにおける個体数密度に関する情報を得ることができる。クラゲ類が深海の生態系全体にどんな影響を与えているか、多様性の維持にどう関わっているのかが少しずつ明らかになってくるのを楽しみにしている。
Technical Report
Full-text available
Recent advances in technology have enabled an unprecedented development of underwater research, extending from near shore to the deepest regions of the globe. However, monitoring of biodiversity is not fully implemented in political agendas and biological observations in the deep ocean have been even more limited in space and time. The Foresight W...
Article
Full-text available
A non-contact method for identification of sparselydistributed plastic pellets is proposed by integrat-ing holography and Raman spectroscopy in thisstudy. Polystyrene (PS) and poly(methyl methacrylate)(PMMA) resin pellets with a size of 3 mm located ina 20 cm water channel were illuminated using a colli-mated continuous wave laser beam with a diame...
Article
Full-text available
Optical particle measurements are emerging as an important technique for understanding the ocean carbon cycle, including contributions to estimates of their downward flux, which sequesters carbon dioxide (CO2) in the deep sea. Optical instruments can be used from ships or installed on autonomous platforms, delivering much greater spatial and tempor...
Article
Full-text available
Separating microplastics from marine and freshwater sediments is challenging, but necessary to determine their distribution, mass, and ecological impacts in benthic environments. Density separation is commonly used to extract microplastics from sediments by using heavy salt solutions, such as zinc chloride and sodium iodide. However, current device...
Article
Full-text available
Removing non-plastic materials is a mandatory process for studying microplastics in environmental samples, and non-plastic materials, both inorganic and organic matter, are often removed chemically through sequential processes. In the multiple chemical treatment processes, the samples need to be collected and the reagent removed at the end of each...
Presentation
Full-text available
Gelatinous zooplankton can be extremely fragile, sometimes with over 95% of their mass comprised of water. Although some taxa can be sampled and observed in an aquarium, many taxa do not survive collection and can only be studied in situ. Many of these taxa are undescribed species, sometimes in new genera, families or even orders. Since holotypes o...
Conference Paper
Gelatinous macrozooplankton can dominate many oligotrophic systems and are especially conspicuous in deep-sea and pelagic ecosystems. Due to the logistical challenges imposed by sea-ice cover, the gelatinous zooplankton fauna of the Arctic Ocean remains largely unknown, with the notable exception of the data collected during the Hidden Ocean series...
Conference Paper
Full-text available
There has been very little research done in the center of the South Pacific Gyre because of the difficulties in sampling so far away from any land. However, the center of the gyre is a scientifically curious and important location due to it being a super-oligotrophic area – like a terrestrial desert. From January 27th to March 2nd 2019, the Japan A...
Poster
Full-text available
Ocean Networks Canada (ONC) operates large seafloor cabled observatory networks in the Arctic and NE Pacific, with some of its long-term observations nearly approaching 15 years of archived data. The seafloor network of 850+ km of backbone cables connects > 50 instrumented sites (>400 oceanographic instruments, >5,000 sensors), in habitats ranging...
Article
Research on so-called "minor taxa" at mesophotic depths has lagged behind that of more commonly researched groups such as fish or hard corals. Exemplar taxa include species of the order Zoantharia, benthic colonial anemones that are cosmopolitan in distribution but understudied in many ecoregion and ecosystems. In this study, we examine the results...
Chapter
The exploitation of deep-sea mineral resources has not yet begun. In order to realize it in the future, various issues need to be addressed. One such issue is establishing an appropriate environmental impact assessment (EIA) technique and a supporting environmental research method. At present, knowledge on the deep-sea environment is quite poor, an...
Article
Juvenile specimens of the scavenging amphipod Pseudocallisoma coecum (Holmes, 1908) were recorded near the bases of the oral arms of the jellyfish Poralia rufescens Vanhöffen, 1902 in the Japan Trench. Video footage and sampling imply a high infection rate of Poralia, with one to six amphipod specimens occurring on each P. rufescens individual. The...
Article
Full-text available
The Seven-arm Octopus, Haliphron atlanticus, was observed holding a coronate medusa, Periphyllopsis braueri, by the remotely-operated vehicle (ROV) Dolphin-3K. The jellyfish was held by the aboral surface within the arms of the octopus. Although obscured at first, the lappets and tentacles of the jellyfish became exposed as the octopus turned towar...
Article
An individual narcomedusa assignable to Solmissus incisa sensu lato was observed having ingested a fish at 573 m depth near the southeast slope of the Kaikata seamount, Japan. Solmissus is a very common deep-sea narco-medusan genus that is widely considered to be a predator specializing on gelatinous plankton. Several cryptic species, with differen...
Article
Loss or stark reduction of the free-swimming medusa or jellyfish stage is common in the cnidarian class Hydrozoa. In the hydrozoan clade Trachylina, however, many species do not possess a sessile polyp or hydroid stage. Trachylines inhabiting freshwater and coastal ecosystems (i.e., Limnomedusae) possess a metagenetic life cycle involving benthic,...
Article
Full-text available
A new genus and species of pennellid copepod, Protosarcotretes nishikawai n. g., n. sp., is described on the basis of an ovigerous female infecting a Pacific viperfish Chauliodus macouni collected from the deep-waters of Suruga Bay, Japan. The new genus exhibits the most plesiomorphic states in the first to fourth legs of pennellids, and is differe...
Article
Full-text available
Large numbers of the leptomedusa Earleria bruuni were observed inside a semi-closed deep-sea caldera during a comparative survey of the macrozooplankton fauna inside and outside the Kurose Hole, Izu-Ogasawara Islands, by the remotely operated vehicle (ROV) ‘Dolphin-3K’, on 24 September 2000. The Kurose Hole is an inactive volcanic caldera of 790 m...
Article
Full-text available
Online biogeographic databases are increasingly being used as data sources for scientific papers and reports, for example, to characterize global patterns and predictors of marine biodiversity and to identify areas of ecological significance in the open oceans and deep seas. However, the utility of such databases is entirely dependent on the qualit...
Technical Report
Full-text available
Marine optical imaging has become a major assessment tool in science, policy and public understanding of our seas and oceans. Methodology in this field is developing rapidly, including hardware, software and the ways of their application. The aim of the Marine Imaging Workshop (MIW) is to bring together academics, research scientists and engineers,...
Article
Full-text available
Optics-based surveys for large unicellular zooplankton were carried out in five different oceanic areas. New identification criteria, in which “radiolarian-like plankton” are categorized into nine different groups, are proposed for future optics-based surveys. The autonomous visual plankton recorder (A-VPR) captured 65 images of radiolarians (three...
Article
Full-text available
We have developed a global biogeographic classification of the mesopelagic zone to reflect the regional scales over which the ocean interior varies in terms of biodiversity and function. An integrated approach was necessary, as global gaps in information and variable sampling methods preclude strictly statistical approaches. A panel combining exper...
Article
A new species of clausophyid siphonophore, Kephyes hiulcus sp. nov. is described. It can most easily be differentiated from its congener Kephyes ovata by the shape of the hydroecium in the anterior nectophore of the polygastric stage. This is open over the entire height of the nectophore in K. hiulcus sp. nov., and it is this character from which i...
Article
Full-text available
A new species of “cydippid” ctenophore, Pukia ohtsukai sp. nov., is described from material collected in Nishino-omote Port, Tanegashima Island, Japan. It can be distinguished from the only other member of the genus by the presence of perradial canals, lack of bilateral diverticula beneath the comb plates, a lower number of comb plates per comb row...
Article
A doliolid species belonging to the genus Paradoliopsis was photographed by an Autonomous Visual Plankton Recorder (AVPR) off the eastern seaboard of Japan in October 2014 at 493–512 m depth. Two Paradoliopsis gonozooids were also captured on the video record of the ROV Crambon at 372–373 m depth during the same cruise. This is the first record of...
Article
Full-text available
Medusae can be conspicuous and abundant members of seafloor communities in deep-sea benthic boundary layers. The epibenthic trachymedusa, Ptychogastria polaris Allman, 1878 (Hydrozoa: Trachylina: Ptychogastriidae) occurs in the cold, high latitude systems of both the northern and southern hemispheres, with a circumpolar distribution in Arctic and s...
Chapter
Full-text available
https://www.crcpress.com/Oceanography-and-Marine-Biology-An-Annual-Review-Volume-54/Hughes-Hughes-Smith-Dale/p/book/9781498747981
Article
Full-text available
Genetic barcodes of arctic medusae and meiobenthic cnidarians have uncovered a fortuitous connection between the medusa Plotocnide borealis Wagner, 1885 and the minute, mud-dwelling polyp Boreohydra simplex Westblad, 1937. Little to no sequence differences exist among independently collected samples identified as Boreohydra simplex and Plotocnide b...
Article
Abyssododecas styx, a new genus and new species of Phtisicidae (Amphipoda), is described based on specimens collected from cold-seep sites at abyssal depths between 5313 and 7322 m in the Japan Trench, North Pacific, using the crewed submersible Shinkai 6500 and the Remotely-Operated Vehicle Kaiko. This is the deepest yet record of a caprellidean a...
Chapter
Submersibles and remotely operated vehicles (ROVs) provide the means for conducting precise and selective sampling of deep-sea organisms both in midwater and in all types of benthic terrain. This chapter introduces the advantages of using these vehicles, their key features and how they differ from each other. Submersible and ROV sampling gear is es...
Article
Full-text available
Hydrozoans display the most morphological diversity within the phylum Cnidaria. While recent molecular studies have provided some insights into their evolutionary history, sister group relationships remain mostly unresolved, particularly at mid-taxonomic levels. Specifically, within Hydroidolina, the most speciose hydrozoan subclass, the relationsh...
Article
Full-text available
A variety of cameras have been, and presently are, mounted on remotely-operated vehicles (ROVs) owned by JAMSTEC. Usages of this video data is varied ― from front-mounted cameras for research and research-related observations, to rear-mounted cameras for checking for tether cable entanglement, and pen cameras to check sample canister contents or di...
Article
Full-text available
We describe a new species of Crambionella , C. helmbiru , from central Java, Indonesia. The combination of the mean number of lappets per octant (14), presence of foliaceous appendages amongst frills on oral-arms, absence of tubercles on the velar lappets, proportion of terminal club length to oral-arm length (0.28), and the body colour distinguish...
Article
Full-text available
An attacking behavior by a cranchiid squid (probably Taonius borealis) on a feather-star was filmed at a depth of 948 m off the Pacific coast of Northeast Honshu. Cranchiid squids have been thought to prey on small planktonic crustaceans or fishes in the mid-layer of the ocean, so this image of one attacking a benthic crinoid is quite unusual. Beca...
Article
The Sulu Sea is a semi-isolated, marginal basin surrounded by high sills that greatly reduce water inflow at mesopelagic depths. For this reason, the entire water column below 400 m is stable and homogeneous with respect to salinity (ca. 34.00) and temperature (ca. 10 °C). The neighbouring Celebes Sea is more open, and highly influenced by Pacific...