Papers by Hiromi K Watanabe
JAMSTEC Report of Research and Development, Mar 1, 2009
In 2004, a department of JAMSTEC, Marine Ecosystem Rearch Division, was reorganized and the Resea... more In 2004, a department of JAMSTEC, Marine Ecosystem Rearch Division, was reorganized and the Research Program for Marine Biology and Ecology was established as one of research programs in the Extremobiosphere Research Center (XBR). This review describes the research activities in this program. In the last 5 years, we have conducted two research projects, Symbisis and Evolution of Marine Organisms Research Project and Marine Ecosystem Research Project. In the former project, we have studied genome of the chemoautotrophic symbiotic bacterium of Calyptogena okutanii (a deep-sea symbiotic clam), and comparative genome analysis of Calyptogena clam symbionts. We have also studied symbiotic mytiliid clams found in whale-fall animal communities, symbiosis found in foraminifers and some other symbiotic systems. These studies have opened a way to address questions not only in mechanisms underling the deep-sea chemoautotrophic sysmbiosis, but also in the origin of eukaryotic organelles. In the latter research project, we have studied plankton and benthos. In the plankton research, we have quantitatively analyzed vertical distribution of animal plankters, diurnal/seasonal changes of their distributions and biomasses, and their contribution to the biological pump (downward transport of organic carbons) in marine ecosystems. We have also studied deep-sea dwelling jellyfishes, their lifecycles and interaction with other organisms, such as mollusks and crustaceans. For future research on the global marine ecosystems, we have developed an AUV (Autonomous Unverwater Vehicle), which can equip with a highdefinition TV camera and/or a VPR (Visual Plankton Recorder). These researches are expected to contiribute to the future marine ecosystem ecology, which is becoming more and more important to overcome the global warming on our planet. In the research of benthos, we have studied growth and distribution of some benthic animals. Spawning of a deep-sea Calyptogena clam has been studied in detail by using a dee-sea observatory system in Sagami-bay. In the research of diversities in benthic organisms, we have investigated various organisms from protists (unicellular eukaryotes) to multicellular animals. These studies will contribute to understanding the biodiversity on the earth. Biological rerearch on deep-sea animals is hampered by difficulties of rearing them in laboratories. We have tried to develop rearing techniques of deep-sea animals in collaboration with Shin-Enoshima Aquarium. We have also found that half decomposed whale bones provide a suitable substratum for many deep-sea symbiotic animals. These techniques seem to be promising to establish the long term rearing technique of deep-sea animals. Since the establishment of JAMSTEC, scientists have reported many new species of deep-sea animals around Japan. However, there had been no textbook of deep-sea biology in Japan. In 2008, we published a textbook of deep-sea biology with many pictures of those animals in situ. We extend this line of out-reach to develop a database of deep-sea animals in 2009. We have also published a children's book of deep-sea living world. We hope that these books will draw attentions for general public and for young children who will become biologists to study deep-sea life in the future. In this review, we also describe our studies on subjects other than the program researches. They are biology of piazophiles, biochemistry of chaperonin in a hyperthomophile, and comparative immunology of marine mammals.
Chigaku Zasshi (Jounal of Geography), 2009
In deep-sea reducing environments, such as hydrothermal vent fields and cold seep areas, biologic... more In deep-sea reducing environments, such as hydrothermal vent fields and cold seep areas, biological communities with huge biomass are often observed. Such communities associated with bacterial chemosynthesis, which are composed of species endemic to these environments, are founded with hydrothermal activities and succeed with changes of activities. Over a longer timescale, genetic deviations among local populations and speciation occur during the course of a series of activities and finally new faunal groups diverged. We attempt to estimate the ages of various hydrothermal phenomena on various timescales from 10 to 10 7 years on the basis of the evolutionary ecology of animals endemic to hydrothermal vents as part of the "Taiga project". In this paper, we introduce communities in hydrothermal vent fields and describe the principals of methodologies for age estimation, which we are now planning, and the expected results.
Diversity and Distributions, 2014
ABSTRACT Aim To characterize the species richness, endemism and community structure of benthic ma... more ABSTRACT Aim To characterize the species richness, endemism and community structure of benthic macro-/megafauna in the deep-sea chemosynthetic ecosystems around the Japanese archipelago and determine the conservation priority for deep-sea chemosynthetic habitats. Location Twenty-seven methane seeps from the Kuril–Japan Trench, Nankai Trough, Ryukyu Trench and Sagami Bay as well as 15 hydrothermal vents from the Izu–Bonin Arc and Okinawa Trough around the Japanese archipelago. Methods Species richness and the number of endemic species from 42 vents and seeps were examined using the distributional data of 155 mollusc, annelid and arthropod species. Multivariate analyses were performed to identify groups of sites with similar assemblage composition. Complementarity analysis was performed to determine the minimum number of sites required to conserve at least one population of all species for all 42 sites and for groups of sites detected by the multivariate analyses. Results The species richness of the deep-sea chemosynthetic sites around the Japanese archipelago was higher in the Okinawa Trough and Sagami Bay where higher methane concentrations were observed. Eight distinct biogeographic regions were detected at the community level, and the community structure was classified according to the geological variables of depth and latitude. Complementarity analysis for all 42 sites indicated 21 sites for conservation, while that for each distinct biogeographic region indicated 30 sites for conservation. Main conclusions As unique communities exist in each geographically isolated region around the Japanese archipelago, priority areas should be identified for each type of bioregion for effective conservation. At least 30 (17 seeps and 13 vents) of 42 sites should be conserved to avoid the extinction of the local populations of deep-sea chemosynthetic macro-/megabenthos.
JAMSTEC Report of Research and Development, 2010
Two types of handcorers with different internal diameters (MBARI type corer [MC] ; 7cm, KITAZATO ... more Two types of handcorers with different internal diameters (MBARI type corer [MC] ; 7cm, KITAZATO type corer [KC] ; 8cm) were evaluated for their sampling efficiency and sampler bias on meiofauna, based on the samples collected with these corers during dives #820 ~ 822 of ROV "Hyper Dolphin" at Myojin Knoll, which is about 150km south-southwest of Hachijo Island. It was suggested that the sampling efficiency became worse when overlying water above sediment is leaked from the core samples, regardless of corer type. Meiofauna in the sediments collected with KC showed the "general" vertical distribution pattern; meiofauna were concentrated in the surface layer of the sediments. On the other hand, in the sediments collected with MC, the vertical profiles of meiofauna were rather "uniform". Furthermore, the community compositions at higher taxonomic level were different from those in the sediments collected with KC. These differences between the corers would be attributed to the differences in core diameter and the degree of disturbance to the edge and surface of the sediment samples. Handcorer-sampling with ROVs or submersibles is essential to the studies on meiofauna around hydrothermal vents. These results of this study, however, suggest that comparing meiofaunal data based on samples collected with different types of handcorers should be done carefully.
JAMSTEC Report of Research and Development, 2014
In order to extract quantitative information on deep-sea benthic animals (no. individuals or biom... more In order to extract quantitative information on deep-sea benthic animals (no. individuals or biomass in an area) using oblique video/photo images taken by deep-sea submersible survey platforms, a new method was established to estimate the imaged area of the seafloor from the oblique images. The trapezoidal area appearing on the lower half of the screen was calculated using underwater horizontal and vertical aperture angles of the camera, the angle of incidence of the camera, and the camera-to-seafloor distance. The incidence angle of the camera was obtained using the angles of vehicle pitch and camera tilt, while the camera-to-seafloor distance was calculated from the lens-to-vehicle bottom distance, horizontal distance of lens-to-altimeter, and vehicle altitude. The areas estimated by the present method from images taken by some submersible survey platforms were comparable to those that were actually measured. With the above parameters, and by focusing on the lower half of an image, our method can be used for estimating the seafloor area from any oblique video/photo images taken by any submersible survey platform. Thus, this method is useful for the extraction of quantitative data on benthic animals from legacy oblique video/photographs acquired by submersible survey platforms.
Molecular Phylogenetics and Evolution, 2008
Previous phylogenetic attempts at resolving barnacle evolutionary relationships are few and have ... more Previous phylogenetic attempts at resolving barnacle evolutionary relationships are few and have relied on limited taxon sampling. Here we combine DNA sequences from three nuclear genes (18S, 28S and H3) and 44 morphological characters collected from 76 thoracican (ingroup) and 15 rhizocephalan (outgroup) species representing almost all the Thoracica families to assess the tempo and mode of barnacle evolution. Using phylogenetic methods of maximum parsimony, maximum likelihood, and Bayesian inference and 14 fossil calibrations, we found that: (1) Iblomorpha form a monophyletic group; (2) pedunculated barnacles without shell plates (Heteralepadomorpha) are not ancestral, but have evolved, at least twice, from plated forms; (3) the ontogenetic pattern with 5 fi 6 fi 8 fi 12+ plates does not reflect Thoracica shell evolution; (4) the traditional asymmetric barnacles (Verrucidae) and the Balanomorpha are each monophyletic and together they form a monophyletic group; (5) asymmetry and loss of a peduncle have evolved twice in the Thoracica, resulting in neither the Verrucomorpha nor the Sessilia forming monophyletic groups in their present definitions; (6) the Scalpellomorpha are not monophyletic; (7) the Thoracica suborders evolved since the Early Carboniferous (340 mya) with the final radiation of the Sessilia in the Upper Jurassic (147 mya). These results, therefore, reject many of the underlying hypotheses about character evolution in the Cirripedia Thoracica, stimulate a variety of new thoughts on thoracican radiation, and suggest the need for a major rearrangement in thoracican classification based on estimated phylogenetic relationships.
JAMSTEC Report of Research and Development, 2009
Journal of the Marine Biological Association of the UK, 2006
ABSTRACT The phylogenetic relationships were analysed based on nucleotide sequences of a mitochon... more ABSTRACT The phylogenetic relationships were analysed based on nucleotide sequences of a mitochondrial gene for cytochrome c oxidase subunit I (COI) for the vestimentiferan tube worm Lamellibrachia juni, which inhabits three extremely acidic hydrothermal vent fields in the South Pacific: the TOTO Caldera in the South Mariana Volcanic Arc, the DESMOS site in the Manus Basin, and the Brothers Caldera in the Kermadec Arc. Six haplotypes were obtained from 34 lamellibrachiids from the three sites. Each haplotype was obtained only from a single site, which suggests that the three populations have been isolated from each other. Haplotypes from the DESMOS site formed a monophyletic cluster. All ten individuals from the TOTO Caldera were classified into the same haplotype, which was shown to form a monophyletic cluster with one of three haplotypes from the Brothers Caldera. The population in the Brothers Caldera was shown to consist of two genetically distinct groups.
Journal of Marine Biology, 2009
We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes of Bathymodiolus ... more We sequenced the mitochondrial ND4 gene to elucidate the evolutionary processes of Bathymodiolus mussels and mytilid relatives. Mussels of the subfamily Bathymodiolinae from vents and seeps belonged to 3 groups and mytilid relatives from sunken wood and whale carcasses assumed the outgroup positions to bathymodioline mussels. Shallow water mytilid mussels were positioned more distantly relative to the vent/seep mussels, indicating an evolutionary transition from shallow to deep sea via sunken wood and whale carcasses. Bathymodiolus platifrons is distributed in the seeps and vents, which are approximately 1500 km away. There was no significant genetic differentiation between the populations. There existed high gene flow between B. septemdierum and B. brevior and low but not negligible gene flow between B. marisindicus and B. septemdierum or B. brevior, although their habitats are 5000-10 000 km away. These indicate a high adaptability to the abyssal environments and a high dispersal ability of Bathymodiolus mussels.
Case reports in oncology, 2014
We present the case of a 40-year-old man with previously treated thymic carcinoma, complaining of... more We present the case of a 40-year-old man with previously treated thymic carcinoma, complaining of gradually worsening back pain. Computed tomography scans of the chest showed multiple pleural disseminated nodules with a pleural effusion in the right thorax. The patient was treated with carboplatin on day 1 plus nab-paclitaxel on day 1 and 8 in cycles repeated every 4 weeks. Objective tumor shrinkage was observed after 4 cycles of this regimen. In addition, the elevated serum cytokeratin 19 fragment level decreased, and the patient's back pain was relieved without any analgesics. Although he experienced grade 4 neutropenia and granulocyte colony-stimulating factor (G-CSF) injection, the severity of thrombocytopenia and nonhematological toxicities such as reversible neuropathy did not exceed grade 1 during the treatment. To our knowledge, this is the first report to demonstrate the efficacy of combination chemotherapy consisting of carboplatin and nab-paclitaxel against thymic car...
The ISME journal, 2014
Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bac... more Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope ((13)C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription...
JAMSTEC Report of Research and Development, 2009
genome of the chemoautotrophic symbiotic bacterium of Calyptogena okutanii (a deep-sea symbiotic ... more genome of the chemoautotrophic symbiotic bacterium of Calyptogena okutanii (a deep-sea symbiotic clam), and comparative genome analysis of Calyptogena clam symbionts. We have also studied symbiotic mytiliid clams found in whale-fall animal communities, symbiosis found in foraminifers and some other symbiotic systems. These studies have opened a way to address questions not only in mechanisms underling the deep-sea chemoautotrophic sysmbiosis, but also in the origin of eukaryotic organelles. In the latter research project, we have studied plankton and benthos. In the plankton research, we have quantitatively analyzed vertical distribution of animal plankters, diurnal/seasonal changes of their distributions and biomasses, and their contribution to the biological pump (downward transport of organic carbons) in marine ecosystems. We have also studied deep-sea dwelling jellyfishes, their lifecycles and interaction with other organisms, such as mollusks and crustaceans. For future research on the global marine ecosystems, we have developed an AUV (Autonomous Unverwater Vehicle), which can equip with a highdefinition TV camera and/or a VPR (Visual Plankton Recorder). These researches are expected to contiribute to the future marine ecosystem ecology, which is becoming more and more important to overcome the global warming on our planet. In the research of benthos, we have studied growth and distribution of some benthic animals. Spawning of a deep-sea Calyptogena clam has been studied in detail by using a dee-sea observatory system in Sagami-bay. In the research of diversities in benthic organisms, we have investigated various organisms from protists (unicellular eukaryotes) to multicellular animals. These studies will contribute to understanding the biodiversity on the earth. Biological rerearch on deep-sea animals is hampered by difficulties of rearing them in laboratories. We have tried to develop rearing techniques of deep-sea animals in collaboration with Shin-Enoshima Aquarium. We have also found that half decomposed whale bones provide a suitable substratum for many deep-sea symbiotic animals. These techniques seem to be promising to establish the long term rearing technique of deep-sea animals. Since the establishment of JAMSTEC, scientists have reported many new species of deep-sea animals around Japan. However, there had been no textbook of deep-sea biology in Japan. In 2008, we published a textbook of deep-sea biology with many pictures of those animals in situ. We extend this line of out-reach to develop a database of deep-sea animals in 2009. We have also published a children's book of deep-sea living world. We hope that these books will draw attentions for general public and for young children who will become biologists to study deep-sea life in the future.
PLoS ONE, 2013
Dispersal ability plays a key role in the maintenance of species in spatially and temporally disc... more Dispersal ability plays a key role in the maintenance of species in spatially and temporally discrete niches of deep-sea hydrothermal vent environments. On the basis of population genetic analyses in the eastern Pacific vent fields, dispersal of animals in the mid-oceanic ridge systems generally appears to be constrained by geographical barriers such as trenches, transform faults, and microplates. Four hydrothermal vent fields (the Kairei and Edmond fields near the Rodriguez Triple Junction, and the Dodo and Solitaire fields in the Central Indian Ridge) have been discovered in the mid-oceanic ridge system of the Indian Ocean. In the present study, we monitored the dispersal of four representative animals, Austinograea rodriguezensis, Rimicaris kairei, Alviniconcha and the scaly-foot gastropods, among these vent fields by using indirect methods, i.e., phylogenetic and population genetic analyses. For all four investigated species, we estimated potentially high connectivity, i.e., no genetic difference among the populations present in vent fields located several thousands of kilometers apart; however, the direction of migration appeared to differ among the species, probably because of different dispersal strategies. Comparison of the intermediate-spreading Central Indian Ridge with the fast-spreading East Pacific Rise and slow-spreading Mid-Atlantic Ridge revealed the presence of relatively high connectivity in the intermediate-and slowspreading ridge systems. We propose that geological background, such as spreading rate which determines distance among vent fields, is related to the larval dispersal and population establishment of vent-endemic animal species, and may play an important role in controlling connectivity among populations within a biogeographical province.
Fisheries Science, 2007
The mitochondrial DNA sequence for the COI region was determined for 73 Panulirus japonicus indiv... more The mitochondrial DNA sequence for the COI region was determined for 73 Panulirus japonicus individuals collected at three sample locations in Japan. Fifty-one haplotypes, including 69 polymorphic sites without insertion and deletion, were detected, of which three dominant haplotypes were shared among the three sample locations. The nucleotide and haplotype diversities at the three sample locations were in the ranges of 0.009-0.010 and 0.959-0.990, respectively. No significant population subdivision was detected among the sample locations based on the Fst value and net nucleotide substitution rate, and analysis of the molecular variance model (AMOVA). There was no characteristic geographic distribution pattern for these haplotypes. These results indicate there is no genetic differentiation between P. japonicus populations in Japan, and support the hypothesis that benthic individuals of P. japonicus are sustained from a population of a common pool of long-period phyllosoma larvae through long-distance larval transport within the Kuroshio Subgyre.
Applied and Environmental Microbiology, 2006
Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their abilit... more Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their ability to derive their nutrition from chemoautotrophic ␥and -proteobacterial endosymbionts. Although host-symbiont relationships in Alviniconcha gastropods from the Central Indian Ridge in the Indian Ocean and the Mariana Trough in the Western Pacific have been studied extensively, host-symbiont relationships in Alviniconcha gastropods from the Southwest Pacific remain largely unknown. Phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences of host gastropods from the Manus, North Fiji, and Lau Back-Arc Basins in the Southwest Pacific has revealed a new host lineage in a Alviniconcha gastropod from the Lau Basin and the occurrence of the host lineage Alviniconcha sp. type 2 in the Manus Basin. Based on 16S rRNA gene sequences of bacterial endosymbionts, two ␥-proteobacterial lineages and one -proteobacterial lineage were identified in the present study. The carbon isotopic compositions of the biomass and fatty acids of the gastropod tissues suggest that the ␥and -proteobacterial endosymbionts mediate the Calvin-Benson cycle and the reductive tricarboxylic acid cycle, respectively, for their chemoautotrophic growth. Coupling of the host and symbiont lineages from the three Southwest Pacific basins revealed that each of the Alviniconcha lineages harbors different bacterial endosymbionts belonging to either the ␥or -Proteobacteria. The host specificity exhibited in symbiont selection provides support for the recognition of each of the host lineages as a distinct species. The results from the present study also suggest the possibility that Alviniconcha sp. types 1 and 2 separately inhabit hydrothermal vent sites approximately 120 m apart in the North Fiji Basin and 500 m apart in the Manus Basin.
Diversity and Distributions, 2014
AimTo characterize the species richness, endemism and community structure of benthic macro-/megaf... more AimTo characterize the species richness, endemism and community structure of benthic macro-/megafauna in the deep-sea chemosynthetic ecosystems around the Japanese archipelago and determine the conservation priority for deep-sea chemosynthetic habitats.To characterize the species richness, endemism and community structure of benthic macro-/megafauna in the deep-sea chemosynthetic ecosystems around the Japanese archipelago and determine the conservation priority for deep-sea chemosynthetic habitats.LocationTwenty-seven methane seeps from the Kuril–Japan Trench, Nankai Trough, Ryukyu Trench and Sagami Bay as well as 15 hydrothermal vents from the Izu–Bonin Arc and Okinawa Trough around the Japanese archipelago.Twenty-seven methane seeps from the Kuril–Japan Trench, Nankai Trough, Ryukyu Trench and Sagami Bay as well as 15 hydrothermal vents from the Izu–Bonin Arc and Okinawa Trough around the Japanese archipelago.MethodsSpecies richness and the number of endemic species from 42 vents and seeps were examined using the distributional data of 155 mollusc, annelid and arthropod species. Multivariate analyses were performed to identify groups of sites with similar assemblage composition. Complementarity analysis was performed to determine the minimum number of sites required to conserve at least one population of all species for all 42 sites and for groups of sites detected by the multivariate analyses.Species richness and the number of endemic species from 42 vents and seeps were examined using the distributional data of 155 mollusc, annelid and arthropod species. Multivariate analyses were performed to identify groups of sites with similar assemblage composition. Complementarity analysis was performed to determine the minimum number of sites required to conserve at least one population of all species for all 42 sites and for groups of sites detected by the multivariate analyses.ResultsThe species richness of the deep-sea chemosynthetic sites around the Japanese archipelago was higher in the Okinawa Trough and Sagami Bay where higher methane concentrations were observed. Eight distinct biogeographic regions were detected at the community level, and the community structure was classified according to the geological variables of depth and latitude. Complementarity analysis for all 42 sites indicated 21 sites for conservation, while that for each distinct biogeographic region indicated 30 sites for conservation.The species richness of the deep-sea chemosynthetic sites around the Japanese archipelago was higher in the Okinawa Trough and Sagami Bay where higher methane concentrations were observed. Eight distinct biogeographic regions were detected at the community level, and the community structure was classified according to the geological variables of depth and latitude. Complementarity analysis for all 42 sites indicated 21 sites for conservation, while that for each distinct biogeographic region indicated 30 sites for conservation.Main conclusionsAs unique communities exist in each geographically isolated region around the Japanese archipelago, priority areas should be identified for each type of bioregion for effective conservation. At least 30 (17 seeps and 13 vents) of 42 sites should be conserved to avoid the extinction of the local populations of deep-sea chemosynthetic macro-/megabenthos.As unique communities exist in each geographically isolated region around the Japanese archipelago, priority areas should be identified for each type of bioregion for effective conservation. At least 30 (17 seeps and 13 vents) of 42 sites should be conserved to avoid the extinction of the local populations of deep-sea chemosynthetic macro-/megabenthos.
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Papers by Hiromi K Watanabe