Toyoho Ishimura
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View article: Carbon source estimation of Banggai cardinalfish, <i>Pterapogon kauderni</i>, otoliths using a novel tracer <scp>Δ<sup>14</sup>C</scp>: New implications for fish metabolism and otolith calcification
Carbon source estimation of Banggai cardinalfish, <i>Pterapogon kauderni</i>, otoliths using a novel tracer <span>Δ<sup>14</sup>C</span>: New implications for fish metabolism and otolith calcification Open
Estimating the metabolic rates of fish is crucial for understanding their physiology and ecology. However, metabolic rate information derived from otolith geochemical data (M oto ) has mainly been obtained from mid to high latitudes, leavi…
View article: Reconstructing the experienced temperature during the larval oceanic migration of anguillid eels from otolith stable oxygen isotopes
Reconstructing the experienced temperature during the larval oceanic migration of anguillid eels from otolith stable oxygen isotopes Open
Migration routes and the depth patterns of anguillid eel larvae migrating long distances from spawning grounds in the ocean remain poorly understood. We used otolith stable isotope analysis to study the oceanic migrations of anguillid eels…
View article: A review of benthic foraminiferal oxygen and carbon isotopes
A review of benthic foraminiferal oxygen and carbon isotopes Open
Stable isotopes in the calcium carbonate of benthic foraminifera provide important paleoenvironmental information about seawater/sedimentary porewaters that these foraminifera live in.Oxygen isotopes provide essential insights about variat…
View article: Stable carbon and oxygen isotope signatures of mantle-derived calcite in Aitutaki lherzolite xenolith: Implications for organic carbon cycle in the oceanic mantle
Stable carbon and oxygen isotope signatures of mantle-derived calcite in Aitutaki lherzolite xenolith: Implications for organic carbon cycle in the oceanic mantle Open
Carbon isotope data is desired to be increased to promote the understanding of carbon cycle throughout in the Earth. Diamond is a key carbonaceous tool to study deep carbon cycle, but most diamond occurrences are limited from kimberlite pi…
View article: Composite calcite and opal test in Foraminifera (Rhizaria)
Composite calcite and opal test in Foraminifera (Rhizaria) Open
Foraminifera are unicellular eukaryotes known to have a shell, called a test, generally made of secreted calcite (CaCO3). For the first time, we report a foraminifera with a composite calcite–opal test in the cosmopolitan and well-studied …
View article: Vertical habitat selection of sardine juveniles inferred from oxygen stable isotope of otolith
Vertical habitat selection of sardine juveniles inferred from oxygen stable isotope of otolith Open
Marine organisms can change their habitat depth based on feeding strategies and physiological requirements. Here, we investigated habitat depth selections of juvenile sardines in the western and eastern North Pacific, Sea of Japan, and Eas…
View article: Migration patterns of the Japanese sardine in the Sea of Japan by combining the microscale stable isotope analysis of otoliths and an ocean data assimilation model
Migration patterns of the Japanese sardine in the Sea of Japan by combining the microscale stable isotope analysis of otoliths and an ocean data assimilation model Open
The Japanese sardine ( Sardinops sagax melanostictus ) is a small pelagic fish found in the Sea of Japan, the marginal sea of the western North Pacific. It is an important species for regional fisheries, but their dispersal and migration p…
View article: Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan
Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan Open
1. Understanding the sources of recruits is essential for stock assessments of marine fish populations. In 2014 and 2019, schools of Japanese sardine in the Sea of Japan and the East China Sea (SJ-ECS), which arrive in Japanese coastal are…
View article: Composite calcite and opal test in Foraminifera (Rhizaria)
Composite calcite and opal test in Foraminifera (Rhizaria) Open
Foraminifera are unicellular eukaryotes known to have a shell, called test, generally made of secreted calcite (CaCO3). We report for the first time a Foraminifera having a composite calcite/opal test in the cosmopolitan and well-studied b…
View article: Spatiotemporal variations of seawater <i>δ</i><sup>18</sup>O and <i>δ</i>D in the Western North Pacific marginal seas near Japan
Spatiotemporal variations of seawater <i>δ</i><sup>18</sup>O and <i>δ</i>D in the Western North Pacific marginal seas near Japan Open
The stable oxygen isotope (δ18O) values of biogenic calcium carbonates (CaCO3) present in hard tissues of marine organisms vary with the δ18O of the surrounding seawater (δ18Osw) and water temperature. Consequently, the ambient water tempe…
View article: Ammonoid extinction versus nautiloid survival: Is metabolism responsible?
Ammonoid extinction versus nautiloid survival: Is metabolism responsible? Open
Understanding the mechanism of selective extinction is important in predicting the impact of anthropogenic environmental changes on current ecosystems. The selective extinction of externally shelled cephalopods at the Cretaceous-Paleogene …
View article: Anaerobic methane‐oxidizing activity in a deep underground borehole dominantly colonized by <scp> <i>Ca</i> </scp> . Methanoperedenaceae
Anaerobic methane‐oxidizing activity in a deep underground borehole dominantly colonized by <span> <i>Ca</i> </span> . Methanoperedenaceae Open
The family Ca . Methanoperedenaceae archaea mediates the anaerobic oxidation of methane (AOM) in different terrestrial environments. Using a newly developed high‐pressure laboratory incubation system, we investigated 214‐ and 249‐m deep gr…
View article: Fe(III)-dependent anaerobic methane-oxidizing activity in a deep underground borehole demonstrated by in-situ pressure groundwater incubation
Fe(III)-dependent anaerobic methane-oxidizing activity in a deep underground borehole demonstrated by in-situ pressure groundwater incubation Open
Summary The family Methanoperedenaceae archaea mediate anaerobic oxidation of methane (AOM) in various terrestrial environments. In this study, we newly developed a high-pressure laboratory incubation system by controlling hydraulic pressu…
View article: Reconstruction of temperature experienced by Pacific bluefin tuna Thunnus orientalis larvae using SIMS and microvolume CF-IRMS otolith oxygen isotope analyses
Reconstruction of temperature experienced by Pacific bluefin tuna Thunnus orientalis larvae using SIMS and microvolume CF-IRMS otolith oxygen isotope analyses Open
This study aimed to reconstruct temperatures experienced during the larval period by adult Pacific bluefin tuna Thunnus orientalis using high-resolution otolith stable oxygen isotope (δ 18 O) analysis. A novel otolith sample preparation pr…
View article: Otolith <i>δ</i>18O and microstructure analyses provide further evidence of population structure in sardine <i>Sardinops sagax</i> around South Africa
Otolith <i>δ</i>18O and microstructure analyses provide further evidence of population structure in sardine <i>Sardinops sagax</i> around South Africa Open
Sardine Sardinops sagax is an ecologically and economically important Clupeid found off the entire South African coast that includes both coastal upwelling and western boundary current systems. Although the management of the sardine fisher…
View article: Temperature dependency equation for chub mackerel (Scomber japonicus) identified by a laboratory rearing experiment and microscale analysis
Temperature dependency equation for chub mackerel (Scomber japonicus) identified by a laboratory rearing experiment and microscale analysis Open
In this study, juveniles of chub mackerel (Scomber japonicus) were reared from eggs in six different temperature treatments, and their otoliths were subjected to micromilling and microvolume stable oxygen isotope (δ18O) analysis. We determ…
View article: Otolith oxygen isotope analysis and temperature history in early life stages of the chub mackerel Scomber japonicus in the Kuroshio–Oyashio transition region
Otolith oxygen isotope analysis and temperature history in early life stages of the chub mackerel Scomber japonicus in the Kuroshio–Oyashio transition region Open
To determine the temperature history of early life stages of chub mackerel (Scomber japonicus), otolith stable oxygen isotope ratios (δ18Ootolith) of larval and juvenile fish collected in the Kuroshio–Oyashio transition area during 2004–20…
View article: Isotopic evidence of connectivity between an inshore vegetated lagoon (nursery habitat) and coastal artificial reefs (adult habitats) for the reef fish Lethrinus lentjan on the Terengganu coast, Malaysia
Isotopic evidence of connectivity between an inshore vegetated lagoon (nursery habitat) and coastal artificial reefs (adult habitats) for the reef fish Lethrinus lentjan on the Terengganu coast, Malaysia Open
Stable isotope analyses of muscle tissue (d13Cmuscle and d15Nmuscle) and otoliths (d13Cotolith and d18Ootolith) were used to retrospectively track habitat uses of Lethrinus lentjan, and to determine any association between Setiu Lagoon (nu…
View article: Advanced approach to analyzing calcareous protists for present and past pelagic ecology: Comprehensive analysis of 3D-morphology, stable isotopes, and genes of planktic foraminifers
Advanced approach to analyzing calcareous protists for present and past pelagic ecology: Comprehensive analysis of 3D-morphology, stable isotopes, and genes of planktic foraminifers Open
Marine protists play an important role in oceanic ecosystems and biogeochemical cycles. However, the difficulties in culturing pelagic protists indicate that their ecology and behavior remain poorly understood; phylogeographic studies base…
View article: Data for: Monsoon-influenced variations of the calcareous and siliceous plankton and productivity of the western Bay of Bengal during the past 80 kyr
Data for: Monsoon-influenced variations of the calcareous and siliceous plankton and productivity of the western Bay of Bengal during the past 80 kyr Open
This supporting information provides the biogeochemical data and planktonic δ18O used in the main article. Contents of this file are 3 tables (Table S1 to S3). Caption for Tables S1 to S3 Table S1. Results of biogenic silica (BSi), CaCO3, …
View article: Combining microvolume isotope analysis and numerical simulation to reproduce fish migration history
Combining microvolume isotope analysis and numerical simulation to reproduce fish migration history Open
Tracking the movement of migratory fish is of great importance for efficient conservation, although this has been technically difficult to achieve in small fish to which artificial tags cannot be attached. We show that migration history ca…
View article: A review of issues on elucidation of climate variability impacts on living marine resources and future perspectives
A review of issues on elucidation of climate variability impacts on living marine resources and future perspectives Open
気候変動が水産資源の変動に与える影響を理解するために,これまで様々な研究が行われてきた。しかし,水産資源生物の生残にとって最も重要と考えられる仔稚魚期に,水産資源生物が実際に経験した環境を観測できないことが,1つの問題となってきた。本稿では,これまで行われてきた研究の概要をまとめるとともに,気候変動に対する水産資源の応答を調べる方法として,仔稚魚の耳石日周輪幅による成長履歴の推定,耳石酸素安定同位体比分析および魚類成長-回遊モデルの融合による経験環境と回遊経路の推定を組み合…
View article: Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment
Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment Open
Recent single-gene-based surveys of deep continental aquifers demonstrated the widespread occurrence of archaea related to Candidatus Methanoperedens nitroreducens (ANME-2d) known to mediate anaerobic oxidation of methane (AOM). However, i…
View article: Temperature dependence of δ 18 O in otolith of juvenile Japanese sardine: Laboratory rearing experiment with micro-scale analysis
Temperature dependence of δ 18 O in otolith of juvenile Japanese sardine: Laboratory rearing experiment with micro-scale analysis Open
We evaluated the use of the stable oxygen isotope (δ18O) in the otolith as a proxy for the temperature history of Japanese sardine Sardinops melanostictus individuals. Japanese sardine juveniles were reared in three different water tempera…
View article: Geochemical imprints of genotypic variants of <i>Globigerina bulloides</i> in the Arabian Sea
Geochemical imprints of genotypic variants of <i>Globigerina bulloides</i> in the Arabian Sea Open
Planktonic foraminifera record oceanic conditions in their shell geochemistry. Many palaeoenvironmental studies have used fossil planktonic foraminifera to constrain past seawater properties by defining species based on their shell morphol…