Ryuta Terada

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Verified

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• PhD
• Professor at Kagoshima University

A molecular-based floristic survey of marine red algal biodiversity was conducted offshore Tanegashima Island, which is located at the northern end of mesophotic coral ecosystems (MCEs), in the Ryukyu Archipelago, Japan. This study provides the first comprehensive catalog of red algae comprising the sublittoral marine flora of offshore Tanegashima...

Bonamia (Haplosporida) are oyster parasites capable of devastating oyster populations. The near-circumglobal distribution of the host generalist B. exitiosa has previously been associated with the natural and anthropogenic dispersal of broadly distributed non-commercial oysters in the Ostrea stentina species complex. Here, we took a global snapshot...

A brown alga, Ecklonia radicosa (Kjellman) Okamura (Laminariales), is one of the canopy-forming algae in the kelp forest, and it is distributed at the lowest latitude among Japanese kelp species. Although the southern distributional limit of this alga is known as Mageshima Island, Kagoshima Prefecture, its presence was believed to have disappeared...

Seasonal changes in the size of the herbal drug red alga Chondria armata (Rhodomelaceae, Ceramiales) were investigated in Kagoshima, Japan, which is near the northern distributional limit in the western Pacific. Additionally, its photosynthetic response to irradiance and temperature was examined using dissolved oxygen sensors and a pulse amplitude...

The effects of four stressors, temperature, irradiance, desiccation and salinity, on the photochemical efficiency (ΔF/F 0 m) of an edible green alga, Caulerpa chemnitzia var. laetevirens from Kagoshima, Japan, were determined for optimizing cultivation and shipping environments using a pulse amplitude modulation-chlorophyll fluorometer. The ΔF/F 0...

In 2021, the current distribution status of seagrass beds in Kagoshima Bay, Kagoshima, Japan was investigated at 77 sites including four sites located outside the bay. At each site, we measured the seagrass bed area by the naked eye using scuba, snorkeling, and coastal walking and recorded the coverage for quadrats (50 cm long and wide), which were...

This study examined the effect of photochemical efficiency (ΔF/Fm′) in cultivated sporophytes of Pyropia yezoensis f. narawaensis under the conchospore-release suppression treatment resulting from postponement of seeding date. Two types of treatment were used to preserve sporophytes: Exp#1) Preservation in a dark aquarium tank; Exp#2) Preservation...

The photochemical efficiency of photosystem II under desiccation stress was examined in the microscopic sporophyte of a cultivated red alga, Pyropia yezoensis f. narawaensis (= Neopyropia yezoensis f. narawaensis; Bangiales) from Saga, Japan, using a pulse amplitude modulation (PAM)-chlorophyll fluorometer. The effective quantum yield (ΔF/Fm') of s...

We investigated the photosynthetic response of Ryuguphycus kuaweuweu (= Umbraulva kuaweuweu, Ulvales), a subtidal green alga from the northern Ryukyu Islands (35–40 m deep), Kagoshima, Japan, to temperature, irradiance, and light spectral limitation using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and dissolved oxygen sensors. The p...

The effects of four stressors, temperature, irradiance, desiccation, and salinity, on the photochemical efficiency ( ΔF/F m ' ) of a green alga, Caulerpa chemnitzia var. laetevirens from Kagoshima, Japan were determined for optimizing cultivation and shipping environments using a pulse amplitude modulation (PAM)-chlorophyll fluorometer. The ΔF/F m...

The effect of temperature and irradiance on the photosynthesis of a tropical seagrass, Halodule uninervis, from Amami-Oshima Island, Kagoshima, Japan, close to the northern distributional limit in the western Pacific, was determined using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and dissolved oxygen sensors. The response of oxygen...

The responses of photochemical efficiency to desiccation and salinity gradients in an intertidal edible brown macroalga, Sargassum fusiforme (Harvey) Setchell (Sargassaceae, Fucales), were determined using a pulse amplitude modulation (PAM)‐chlorophyll fluorometer. The effective quantum yields (ΔF/Fm'; = ΦPSII) of photosystem II (PSII) dropped to z...

The effect of temperature, light‐spectrum, desiccation and salinity gradients on the photosynthesis of a Japanese subtidal brown alga, Sargassum macrocarpum (Fucales), was determined using a pulse amplitude modulation‐chlorophyll fluorometer and dissolved oxygen sensors. Temperature responses of the maximum (Fv/Fm in darkness) and effective (ΔF/Fm′...

The effect of temperature and light on the photosynthesis of the seedlings of Zostera marina from the annual population in Kagoshima, Japan was determined by field and laboratory measurements using a pulse amplitude modulation (PAM)-chlorophyll fluorometer. The response of oxygenic photosynthesis to temperature (8–40°C) was also examined with disso...

The interactive effects of temperature and irradiance including spectral light quality on the photosynthesis of a brown alga, Saccharina japonica (var. japonica, Laminariales) from Hokkaido, Japan were examined using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and dissolved oxygen sensors. Assessment of maximum quantum yields (in dar...

To determine the species distribution of an amnesic shellfish poisoning (ASP) toxins-producing diatom Nitzschia navis-varingica outside its current restricted geographical distribution range in Asian coastal waters, samples were collected from two sites of Bootless Bay, located on southwest coast of Papua New Guinea near Port Moresby. A total of tw...

The important role of vegetated ecosystems in the sequestration of carbon has gained strong interest across a wide variety of disciplines. With evidence growing of the potential for macroalgae ecosystems to capture carbon, there is burgeoning interest in applying newfound knowledge of carbon capture rates to better understand the potential for carb...

We determined the response of photochemical efficiency to desiccation and salinity in an edible brown alga, Saccharina japonica (var. japonica), using a pulse amplitude modulation chlorophyll fluorometer. Natural populations of this species in Muroran, Hokkaido, Japan are most of the time immersed in the subtidal zone; however, those at the uppermo...

Significance Originally isolated from the red alga Chondria armata , domoic acid (DA) is best known as a potent marine neurotoxin produced by oceanic harmful algal blooms of planktonic diatoms. Sequencing efforts to date of kainoid-producing red algae have focused exclusively on a closely related molecule, kainic acid, leaving a gap in the understa...

The phenology and environmental characteristics of two brown algae, Sargassum hemiphyllum and S. glaucescens (Fucales) were investigated at Yamagawa, Ibusuki, Kagoshima Bay, Japan. Their vertical distributions in the upper subtidal zone were determined using the line transect method. The two species were found on the rocks and cobbles at a depth of...

Ecklonia radicosa (Laminariales), a canopy-forming brown alga, was reported to have disappeared since 2016 at a site surveyed under a nationwide long-term monitoring survey for the natural ecosystem (Monitoring Site 1000, Japanese Ministry of Environment) in Nagashima Island, Kagoshima Prefecture, Japan. The distribution of seaweed assemblages alon...

We collected the deep-water species Rhodymenia prostrata (Rhodymeniaceae, Rhodophyta), for the first time in nearly 50 years, from the type locality off Mageshima Island, Japan. Our combined rbcL, cox1 and 28S rDNA analyses suggested that R. prostrata belongs in the genus Halopeltis but is distinct from all other Halopeltis species. However, the bi...

We determined the chronic effects of dehydration on the photochemical efficiency of a cultivated brown alga, Undaria pinnatifida (Alariaceae, Laminariales), in young sporophytes as cultivated sporelings. The effective quantum yields of photosystem II (ΔF/Fm′) at 50% humidity decreased markedly after 20 min of emersion and dropped almost zero after...

The combined effects of temperature and irradiance and the influences of desiccation and salinity on the photochemical efficiency in a subtropical red alga, Phycocalidia tanegashimensis (= Pyropia tanegashimensis, Bangiaceae) from Tanegashima Island, Japan, were determined to reveal how this species has adapted to its habitat in the splash zone. Co...

Single‐gene markers, such as the mitochondrial cox1, microsatellites, and single nucleotide polymorphisms are powerful methods to describe diversity within and among taxonomic groups and characterize phylogeographic patterns. Large repositories of publicly‐available, molecular data can be combined to generate and evaluate evolutionary hypotheses fo...

Domoic acid (1, DA), a member of the natural kainoid family, is a potent agonist of ionotropic glutamate receptors in the central nervous system. The chemical synthesis of DA and its derivatives requires considerable effort to establish a pyrrolidine ring containing three contiguous stereocenters. Recently, a biosynthetic cyclase for DA, DabC, was...

We present a descriptive account of the dynamics of epiphytic diatoms, epifauna, and the leaf surface area of Zostera marina in a shallow water ecosystem. We hypothesized that the growth stage of the host macrophyte (i.e., leaf surface area) influenced the presence of epiflora and epifauna, as well as that the leaf surface area and epifaunal popula...

We investigated the effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of juvenile (JS) and mature sporophytes (MS) of a temperate edible brown alga Undaria pinnatifida cultivated in northeastern Japan, using optical dissolved oxygen sensors and pulse amplitude modulation (PAM)–chlorophyll fluorometry. Photos...

We examined the effects of four stressors, irradiance, temperature, desiccation, and salinity on the photosynthesis of a red alga, Agarophyton vermiculophyllum (= Gracilaria vermiculophylla, Gracilariales, Rhodophyta) from its native distributional range in Hokkaido and Kagoshima, Japan. Photosynthesis-irradiance (P-E) curves at 8, 16, and 28°C sho...

We report two red algal species, Chondracanthus saundersii C.W. Schneider & C.E. Lane (Gigartinaceae, Gigartinales) and Schottera koreana M.S. Calderon, T.H. Seo & S.M. Boo (Phyllophoraceae, Gigartinales), from Japan for the first time based on molecular and morphological analyses. A C. saundersii specimen was collected at a depth of 35 m offshore...

The chronic effect of dehydration on photochemical efficiency was determined in two heteromorphic life-history stages of a cultivated red alga, Neopyropia yezoensis f. narawaensis (=Pyropia yezoensis f. narawaensis; Bangiaceae, Bangiales) from Saga, Kyushu Island, Japan. The response to acute emersion (~1440-min) under 50% humidity was dissimilar b...

The effects of temperature, irradiance, and desiccation on the photosynthesis of a cultivated Japanese green alga Caulerpa lentillifera (Caulerpaceae) were determined by a pulse amplitude modulation (PAM)-chlorophyll fluorometer and dissolved oxygen sensors. The photochemical efficiency in the photosystem II (F v /F m and ΔF/F m ') during the 72-h...

A new flattened species of Gracilariopsis from Mageshima Island, Japan is recognized based on morphological and molecular analyses of rbcL and cox1 DNA sequences. We name this new species Gp. mageshimensis sp. nov. The rbcL and cox1 analyses suggest that Gp. mageshimensis belongs to the Gracilariopsis clade, and that it is distinct from other Graci...

We determined the effects of irradiance, temperature, and desiccation on the photosynthesis of a brown alga, Sargassum muticum (Fucales), from its native distributional range in Japan by using a pulse amplitude modulation (PAM)-chlorophyll fluorometer and optical dissolved oxygen sensors. Photosynthesis-irradiance curves at three temperatures (8, 2...

The effects of temperature on the photosynthesis and growth of a subtropical red alga, Phycocalidia tanegashimensis (= Pyropia tanegashimensis, Bangiaceae, Bangiales) from Tanegashima Island, Japan, were determined to better understand the ecology of the macroscopic gametophyte. Net photosynthesis–irradiance (P–E) curves, determined at 12, 20, and...

The reproductive structures, early development and carotenoid composition of Umbraulva kuaweuweu, which is a deep-water ulvacean species recently reported from Hawaii, are reported for the first time using the specimens collected by dredging at~30 m depth from Ogasawara Islands and Mageshima in southern Japan. Although Umbraulva kuaweuweu had sipho...

The genus Meristotheca (Solieriaceae) includes fifteen currently accepted species. They are widely distributed throughout the tropics and subtropics of both hemispheres, inhabiting the intertidal and subtidal regions of rocky shores. Molecular phylogenetic studies allowed a precise understanding of the species diversity and biogeography of the genu...

“Monitoring Sites 1000” – Japan's long‐term monitoring survey was established in 2003, based on the Japanese Government policy for the conservation of biodiversity. Ecological surveys have been conducted on various types of ecosystems at approximately 1000 sites in Japan for 15 years now and are planned to be carried out for 100 years. Since 2008,...

Characteristic underwater views of the temperate and subarctic seaweed communities in Japan. Top left: Saccharina japonica in Muroran, Hokkaido. Bottom left: Ecklonica radicosa in Satsuma-Nagashima, Kagoshima. Bottom center: Ecklonia cava subsp. kurome in Takeno, Hyogo. Right: Sargassum communities including Sargassum siliquastrum and Sargassum pat...

This study examined the effects of temperature and irradiance on photosynthetic characteristics of the macroscopic sporophyte (SPO) and microscopic gametophyte (GAM) stages of a subarctic brown alga, Saccharina japonica var. japonica (Laminariales) from Hokkaido, Japan. In vitro measurements under short-and long-term exposures were carried out by u...

The chronic effects of three different stressors, irradiance, temperature, and desiccation, on Photosystem II (PSII) photochemical efficiency were investigated in two heteromorphic life-history stages of a cultivated red alga, Pyropia yezoensis f. narawaensis (Bangiales) from Japan. The maximum quantum yields of PSII (F v /F m) over the range of te...

Seaweed beds form a canopy affecting water flow in and around them, and therefore affect mass transport processes between the canopy and the surrounding seawater. Nutrients and physiological byproducts are transferred to and from the bulk seawater and the macroalgae surface, where they are absorbed or released. A change in the canopy structure caus...

Understanding the physiological responses of kelp to environmental parameters is essential for the conservation of natural kelp beds and increased cultivation yield. We investigated the effects of photosynthe-tically active radiation (PAR) and temperature on photosynthesis of a subarctic edible brown alga, Saccharina sculpera (Laminariales), using...

Global changes in climatic conditions are expected to disrupt marine ecosystems. Ocean warming is one of many concerns, since more than 90% of the Earth's warming occurs in the oceans. Macrophyte‐dominated communities recently have become the focus of climate mitigation due to their high carbon sequestration rate. Therefore, there is an urgent need...

The temperature and light responses of photosynthesis in two freshwater red algae, Virescentia helminthosa and Sheathia arcuata (Batrachospermaceae), were determined by a pulse amplitude modulation (PAM) chlorophyll fluorometer and dissolved oxygen sensors. Net oxygenic photosynthesis-photosynthetically active radiation (PAR) models of V. helmintho...

This study investigated the effects of different light spectral qualities and temperature on the photosynthesis and pigment content of a subtidal edible red alga, Meristotheca papulosa. Photosynthesis–irradiance (P–E) experiments were carried out under red (660 nm), blue (450 nm), green (525 nm, light-emitting diodes), and white light (visible ligh...

Effects of seaweed deformation on photosynthesis rate and nutrient uptake rate. Jpn. J. Phycol. (Sôrui) 68: 1-8, March 10, 2020 For seaweeds with complex structures, such as the Sargassum, increasing water velocities can cause the fronds to collapse into a more streamlined shape. Such deformation makes it difficult for seawater to flow through the...

Taxonomy of the little‐studied brown algal species Punctaria mageshimensis (Ectocarpales s.l.) was reexamined by molecular phylogeny and morphology. In the genetic analyses of newly collected specimens using plastid rbcL and psaA gene sequences, the specimens morphologically referable to P. mageshimensis were phylogenetically distant from Ectocarpa...

We determined the effect of irradiance and temperature on the photosynthesis of two heteromorphic life‐history stages of an endangered freshwater red alga, Thorea gaudichaudii (Thoreales) by laboratory and field measurements. Net oxygenic photosynthesis–irradiance models of macroscopic and microscopic life‐history stages revealed similar low irradi...

The evolutionary and population demographic history of marine red algae in East Asia is poorly understood. Here we reconstructed the phylogeographies of two upper intertidal species endemic to East Asia, Gelidiophycus divaricatus and G. freshwateri. Phylogenetic and phylogeographic inferences of 393 mitochondrial cox1, 128 plastid rbcL, and 342 nuc...

The effects of irradiance, temperature, thermal‐ and chilling‐light sensitivities on the photosynthesis of a temperate alga, Sargassum macrocarpum (Fucales) were determined by a pulse amplitude modulation (PAM)‐chlorophyll fluorometer and dissolved oxygen sensors. Oxygenic photosynthesis–irradiance curves at 8, 20, and 28°C revealed that the maximu...

Four kainic acid (KA, 1)-related compounds, 4-hydroxykainic acid (2), allo-4-hydroxykainic acid (3), N-dimethylallyl-l-glutamic acid (4), and N-dimethylallyl- threo-3-hydroxyglutamic acid (5), were isolated from the red alga Digenea simplex. The structures of these compounds were elucidated using spectroscopic methods. Compounds 2 and 3 are possibl...

The combined effects of irradiance and temperature on photosystem II (PSII) photochemical efficiency were investigated in the microscopic sporophyte and macroscopic gametophyte stages of the cultivated red algae Pyropia yezoensis f. narawaensis and Pyropia tenera (Bangiales) from Kyushu Island, Japan. Continuous 12-h exposures to 10, 100, and 1000...

The effect of photosynthetically active radiation (PAR) and temperature on the photosynthesis of a temperate Japanese edible brown alga, Cladosiphon umezakii (Chordariaceae, Ectocarpales), from Honshu Island, Japan, was determined in the heteromorphic life history stages (macroscopic and microscopic) by using pulse-amplitude modulation (PAM) fluoro...

Effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of a subarctic edible brown alga, Saccharina angustata (Laminariaceae, Laminariales), from Hokkaido, Japan, were determined using a pulse amplitude modulation (PAM)–chlorophyll fluorometer and optical dissolved oxygen sensors. Photosynthesis–PAR experiments a...

Understanding of the physiological responses of kelp to environmental parameters is crucial, especially in the context of environmental change that may have contributed to the decline of kelp forests all over the world. The current study presents the photosynthetic characteristics of the macroscopic sporophyte and microscopic gametophyte stages of...

A new species of marine sand‐dwelling dinoflagellate, Plagiodinium ballux N. Yamada, Dawut, R. Terada & T. Horiguchi is described from a deep (36 m) seafloor off Takeshima Island, Kagoshima Prefecture, Japan in the subtropical region of the northwest Pacific. The species is thecate and superficially resembles species of Prorocentrum, but possesses...

The effect of photosynthetically active radiation (PAR) and temperature on the photosynthesis of an endangered Japanese freshwater red alga, Thorea okadae (Thoreaceae, Thoreales), was determined by using pulse-amplitude modulation (PAM) fluorometry and dissolved oxygen sensors. The macroscopic life history stage (gametophyte) was observed on pebble...

In Japan, fresh cultivated green alga, Caulerpa lentillifera (Caulerpaceae, Bryopsidales), are packed into polystyrene containers without seawater. They can stay fresh for 1 week inside the container under room temperature, suggesting a high tolerance to desiccation. This tolerance was evaluated in the present study by employing methods based on pu...

The combined effects of photosynthetically active radiation (PAR) and temperature on the photosynthesis of a temperate Japanese brown alga, Sargassum patens (Fucales), were determined by field and laboratory measurements. Underwater measurements of the natural population of this alga in Kagoshima, Japan, revealed that the effective quantum yield (Φ...

Photosynthetic responses to temperature and photosynthetically active radiation (PAR) were investigated on the heteromorphic life history stages (macroscopic and microscopic stages) of an edible Japanese brown alga, Cladosiphon okamuranus from the Ryukyu Islands. Measurements were carried out by using optical dissolved oxygen sensors and a pulse‐am...

The interactive effects of photoinhibition and chilling stress on the photosynthesis of a freshwater red alga, Nemalionopsis tortuosa from Kagoshima, Japan. Jpn. J. Phycol. (Sôrui) 66: 1-6, March 10, 2018 The occurrence of photoinhibition caused by chilling and light stress on the photosynthetic performance of the freshwater red alga, Nemalionopsis...

Photosynthetic responses to photosynthetically active radiation (PAR) and temperature were investigated in the macroscopic sporophyte (SPO) and microscopic gametophyte (GAM) stages of the brown alga Costaria costata from Hokkaido, Japan. Measurements of net photosynthesis, respiration rates and photochemical efficiency were carried out using dissol...

Domoic acid (DA, 1), a potent neurotoxin that causes amnesic shellfish poisoning, has been found in diatoms and red algae. While biosynthetic pathway towards DA from geranyl diphosphate and L-glutamate has been previously proposed, its late stage is still unclear. Here, six novel DA related compounds, 7'-methyl-isodomoic acid A (2) and B (3), N-ger...

Rapid evolution of non-native species can facilitate invasion success, but recent reviews indicate that such microevolution rarely yields expansion of the climatic niche in the introduced habitats. However, because some invasions originate from a geographically restricted portion of the native species range and its climatic niche, it is possible th...

Photosynthetic responses to photosynthetically active radiation (PAR) and temperature were examined in the red alga Solieria pacifica from deep (35 m) and shallow (5 m) portions of the sublittoral zone in Kagoshima, Japan. Dissolved oxygen sensors and pulse-amplitude modulated (PAM) fluorometry were used for the measurements of net photosynthesis,...

Studies of the taxonomy and diversity of flattened Gracilaria species which occur commonly in coastal areas of Thailand are few and underestimate species richness. Recently, flattened Gracilaria plants were collected along the west coast of southern Thailand (Andaman Sea). We describe a new flattened Gracilaria species, Gracilaria coppejansii Muang...

A new species of benthic marine dinoflagellate, Pyramidodinium spinulosum Horiguchi, Moriya, Pinto & Terada is described from the deep (36 m) seafloor off Mageshima Island, Kagoshima Prefecture, Japan in the subtropical region of the northwest Pacific. The life cycle of the dinoflagellate consists of a dominant, attached, dome-shaped, vegetative fo...

The chronological change of photosynthetic efficiency in a frozen storage treatment of the Japanese Nori cultivation industry was examined in the cultivated red alga, Pyropia yezoensis f. narawaensis (Saga-#5 Strain, Bangiales) by using pulse-amplitude fluorometry. During the desiccation process that was conducted after the nursery cultivation seas...

The identification of native sources and vectors of introduced species informs their ecological and evolutionary history and may guide policies that seek to prevent future introductions. Population genetics provides a powerful set of tools to identify origins and vectors. However, these tools can mislead when the native range is poorly sampled or f...

The successful cultivation of the Japanese Kappaphycus sp. (K. striatus auctorum japonicorum) in Okinawa, Japan, requires the detailed understanding of its physiological response to environmental factors. The photosynthetic performance of this native red alga was investigated under a variety of temperature and photosynthetic active radiation (PAR)...