Tomohiro Kuwae

• Dr
• Group Head at Port and Airport Research Institute

We show that a higher vertebrate can graze surficial intertidal biofilm, previously only considered a food source for rasping invertebrates and a few specialized fish. Using evidence from video recordings, stomach contents, and stable isotopes, we describe for the first time the grazing behavior of Western Sandpipers (Calidris mauri) and estimate t...

Ecology Letters (2012) 15: 347–356 Food webs are comprised of a network of trophic interactions and are essential to elucidating ecosystem processes and functions. However, the presence of unknown, but critical networks hampers understanding of complex and dynamic food webs in nature. Here, we empirically demonstrate a missing link, both critical a...

Carbon captured by marine organisms helps sequester atmospheric CO2 , especially in shallow coastal ecosystems, where rates of primary production and burial of organic carbon (OC) from multiple sources are high. However, linkages between the dynamics of OC derived from multiple sources and carbon sequestration are poorly understood. We investigated...

Estuarine and shallow coastal systems (ESCS) are recognized as not only significant organic carbon reservoirs but also emitters of CO2 to the atmosphere through air–sea CO2 gas exchange, thus posing a dilemma on ESCS’s role in climate change mitigation measures. However, some studies have shown that coastal waters take up atmospheric CO2 (Catm), al...

'Blue Carbon', which is carbon captured by marine living organisms, has recently been highlighted as a new option for climate change mitigation initiatives. In particular, coastal ecosystems have been recognized as significant carbon stocks because of their high burial rates and long-term sequestration of carbon. However, the direct contribution of...

Rising seawater temperatures from climate change have caused coral bleaching, risking coral extinction by century’s end. To save corals, reef restoration must occur alongside other climate-change mitigation. Here we show the effectiveness of habitat creation on artificial structures for rapid coral restoration in response to climate change. We use...

Seaweed farming has emerged as a potential Blue Carbon strategy, yet empirical estimates of carbon burial from such farms remain lacking in the literature. Here, we quantify carbon burial in 20 seaweed farms distributed globally, ranging from 2 to 300 years in operation and from 1 to 15,000 ha in size. The thickness of sediment layers and stocks of...

Kelp forests, vital to global biodiversity and coastal economies, face degradation and underfunded conservation. The State of the World’s Kelp Forests finds that 16% of the kelp biome is protected, 2% of the restoration target is met, and provides a rallying call to meet global commitments for kelp forest conservation.

LiDAR employing a green laser, which exhibits high underwater transparency, has been rapidly adopted for the measurement of coastal bathymetry. The green LiDAR scanner has become lighter and can be mounted to UAVs, thus it is anticipated that it will be used for measuring coastal areas in various environments. However, there are currently no techni...

Atmospheric CO2 removal by macroalgal beds has attracted attention, and the macroalgal biomass is an important metric for calculating CO2 removal. Conventional dive surveys are highly accurate but have limited areal coverage. On the other hand, remote sensing methods such as aerial photography have high areal coverage but do not provide detailed in...

Understanding the spatial distribution (canopy height and biomass) of seagrass meadows is important for improving and utilizing the various environmental values of seagrass meadows. However, conventional survey methods for the spatial distribution of seagrass face the challenge of achieving both efficiency and accuracy. In this study, point cloud d...

This paper explores the potential synergies that can arise from the intersection of payments for ecosystem services (PES) and carbon credits. The Yokohama Blue Carbon Project encompasses seagrass beds and seaweed farms, which serve as a prime example of how climate mitigation measures can align with the enhancement of ecosystem functions. Notably,...

Stable isotope analysis is robust tool to elucidate the diet, trophic position, and migration of typically large, highly mobile marine predators such as elasmobranchs. However, it is necessary to understand the diet–tissue discrimination factors and isotopic turnover rates of target animals. In this study, diet-switching experiments were conducted...

The coastal ocean represents an important global carbon sink and is a focus for interventions to mitigate climate change and meet the Paris Agreement targets while supporting biodiversity and other ecosystem functions. However, the fate of the flux of carbon exported from seaweed forests—the world’s largest coastal vegetated ecosystem—is a key unkn...

Carbon cycles in coastal waters are highly sensitive to human activities and play important roles in global carbon budgets. CO2 sink–source behavior is regulated by spatiotemporal variations in net biological productivity, but the contribution of macrophyte habitats including macroalgae aquaculture to atmospheric CO2 removal has not been well quant...

Mangrove creeks have extremely large carbonate chemistry parameters (partial pressure of carbon dioxide (pCO2), dissolved inorganic carbon (DIC), and total alkalinity (TA)) owing to the porewater export by tidal pumping. In this study, the relationship between tidal oscillations and carbonate chemistry parameters was clarified, and CO2 emissions fr...

The role of shallow coastal ecosystems in mitigating climate change is drawing the attention of researchers, policymakers, and citizens. However, to date there has been no nationwide estimate of atmospheric carbon dioxide (CO2) uptake and carbon storage by shallow coastal ecosystems in Japan. In this study, in accordance with Intergovernmental Pane...

The global area and distribution of shallow water ecosystems (SWEs), and their projected responses to climate change, are fundamental for evaluating future changes in their ecosystem functions, including biodiversity and climate change mitigation and adaptation. Although previous studies have focused on a few SWEs, we modelled the global distributi...

This ICEF Blue Carbon Roadmap summarizes the potential of blue carbon as one of the negative emission technologies to achieve net-zero emissions. In the roadmap, blue carbon is defined as the CO2 captured and stored by mangroves, tidal marshes, seagrass beds, and natural macroalgae beds as well as macroalgal farming such as kelp and sargassum. The...

The suggestion that seaweed farming contribute to carbon sequestration below the farms was tested by quantifying, combining organic carbon density with sediment accumulation estimates in soils below seaweed farms, in 21 seaweed farms distributed globally, ranging up to 300 years in operation and 15,000 ha in size. One in every four farms sampled wa...

Dredged soil was used as the base material for the construction of tidal flats. We investigated the carbon residual rate when the organic matter contained in dredged soil was incorporated in the tidal flats created in Hannan 2 ku, 17 years after completion. Vertical samples of the dredged soil layer were collected using a handy geoslicer with a len...

Our knowledge of the factors that can influence the stock of organic carbon (OC) that is stored in the soil of seagrass meadows is evolving, and several causal effects have been used to explain the variation of stocks observed at local to national scales. To gain a global‐scale appreciation of the drivers that cause variation in soil OC stocks, we...

Despite the potential for carbon storage in tidal flats, little is known about the details of relevant processes because of the complexity of intertidal physical and chemical environments and the uniqueness of the biota. We measured air-water carbon dioxide (CO2) fluxes and water-sediment oxygen (O2) fluxes over a tidal flat in Tokyo Bay by the edd...

The use of stable isotopes of carbon ( δ ¹³ C) and nitrogen ( δ ¹⁵ N) from feces and breath offers potential as non-destructive tools to assess diets and nutrition. How stable isotope values derived from breath and feces compare with those from commonly used tissues, such as blood fractions and liver, remains uncertain, including understanding the...

As climate change has attracted increasing global attention, carbon neutral ports (CNPs) have been set as government policies in Japan. In this research, with the aim of providing a more reliable basis for policy making concerning ports, we proposed the carbon storage through stable containment of organic carbon present in dredged soil as a new cli...

Estuaries and coastal waters are generally significant emitters of CO2 to the atmosphere. Globally, submarine groundwater discharge (SGD) is a significant driver of inorganic carbon dynamics and the partial pressure of CO2 in water [pCO2(water)] in estuaries and coastal waters. However, there are few studies of CO2 emission and SGD in large tropica...

Shorebirds use key migratory stopover habitats in spring and fall where body proteins are replenished and lipids stored as fuel for the remaining journey. The Fraser River estuary, British Columbia, Canada, is a critical spring stopover site for hundreds of thousands of migrating western sandpiper, Calidris mauri, and dunlin, Calidris alpina. Inter...

The term “blue carbon” is still rather new, having been coined in 2009. However, the blue carbon concept and the role of blue carbon stored in shallow coastal ecosystems, as part of nature-based or green infrastructure, in mitigating climate change and providing other ecosystems services, such as disaster risk reduction, infrastructure resilience,...

The "blue carbon" concept and the role of blue carbon stored in shallow coastal ecosystems in mitigating climate change have attracted attention worldwide. In addition to typical blue carbon ecosystems, such as mangroves, tidal marshes, and seagrass meadows, macroalgal beds and macroalgae farming are also gaining recognition as potential blue carbo...

Soft‐bottomed intertidal flats are essential foraging areas for shorebirds but are severely impacted by threats such as coastal development and climate change. Notwithstanding the urgency for humanintervention (conservation, restoration and creation) of tidal flats, few ecologically based technical guidelines exist for the artificial (clearly inten...

The utilization of environmental DNA(eDNA) is being considered as a new method for monitoring seagrass beds. In field surveys, the amount of eDNA of seagrass was below the minimum limit of quantification by using the conventional method that is often performed in freshwater areas for animals. In this study, we assumed water sample condition with a...

Shorebirds wade in shallow waters along shorelines searching for food. More than a million shorebirds visit the San Francisco Estuary each year during their migration to feast on the insects, worms, clams, and crabs that live on or under the surface of the sand or mud. The abundant food in the Estuary provides shorebirds with the energy they need t...

Nature-based solutions (NbS), such as the implementation of environmental conservation and restoration as public works projects, require accurate and cost-effective assessments of the values related to the projects. The values should represent collective ecosystem services, individual services such as food provision and water purification, and othe...

Human interventions have had unintended consequences for the diverse functions of various ecosystems. Hydrological interventions have the potential to alter vegetated habitats in coastal nearshore ecosystems, but little is known about the impacts on organic carbon (Corg) sequestration, which plays an important role in climate change mitigation. We...

The role of coastal blue carbon ecosystems in climate mitigation and adaptation efforts has been recognized. Blue carbon ecosystem functionality is one component of coastal nature-based or green–gray infrastructure multifunctionality, which includes contributions by nature to disaster risk reduction, infrastructure resilience, erosion control, land...

Shallow coastal ecosystems are reservoirs of carbon derived from allochthonous organic matter and autochthonous organic matter produced by microalgae and macrophytes. Carbon stored in vegetated coastal ecosystems has attracted broad attention as an important component of carbon sinks. Characterizing the source of carbon in sediments is essential fo...

We evaluated the contribution of net biological effects (photosynthesis + respiration + decomposition) to the carbonate parameters and air–water CO2 fluxes in Tokyo Bay, Ise Bay, and Osaka Bay in Japan. The carbonate parameters (fugacity of CO2, total alkalinity, and dissolved inorganic carbon) were measured mainly by cargo ships traveling between...

Reduction in riverine freshwater supply due to climate change as well as anthropogenic activities are documented throughout the globe. How river discontinuity in upstream reaches and the subsequent reduction in freshwater influx alter inorganic and organic carbon dynamics in downstream estuaries adjacent to mangroves has been rarely reported. We in...

A blue carbon offset system and a system in which a part of the entrance fee and donations from companies and others are used as financial mechanisms for environmental activities at Hakata Port were established. However, the blue carbon offsetting system is not sufficiently appealing to the ESG management of companies because it is difficult to con...

Coastal vegetated habitats like seagrass meadows can mitigate anthropogenic carbon emissions by sequestering CO2 as “blue carbon” (BC). Already, some coastal ecosystems are actively managed to enhance BC storage, with associated BC stocks included in national greenhouse gas inventories. However, the extent to which BC burial fluxes are enhanced or...

Green port structures (i.e. green infrastructure in ports and harbors) featuring habitats for marine organisms have been promoted in Japan as part of a comprehensive policy to reduce the environmental impact of ports and carry out habitat conservation, restoration, and creation. In this study, we evaluated the ecosystem services provided by green p...

We investigated the diet and chick body mass of Rhinoceros Auklets Cero-rhinca monocerata at four breeding sites in Hokkaido in 2016 and 2017. Matsumae-kojima, Teuri Island and Todo Island are in the southern, middle and northern Tsushima Warm Current system, respectively, although Todo Island is located also beside the colder water mass of the Sea...

Hybrid infrastructure combining gray and green infrastructure should be more cost-effective than gray infrastructure; however, its cost-effectiveness and cost-effective methods for its construction are not clear. Here we used pro-environment breakwaters, having the original breakwater function of wave attenuation along with the additional function...

Globally, water bodies adjacent to mangroves are considered significant sources of atmospheric CO2. We directly measured the partial pressure of CO2 in water [pCO2(water)] and related biogeochemical parameters with high temporal resolution, covering both diel and tidal cycles, in the mangrove-surrounding waters around the northern Bay of Bengal dur...

• Dietary specialization is common in animals and has important implications for individual fitness, inter‐ and intraspecific competition, and the adaptive potential of a species. Diet composition can be influenced by age‐ and sex‐related factors including an individual's morphology, social status, and acquired skills; however, specialization may o...

Issues related to climate change in coastal areas have been addressed in a wide variety of academic fields and societies, including meteorology, marine physics, chemistry, biology, ecology, policy science, and economics. However, the efforts and initiatives of each relevant academic field or society are rarely shared because climate change science...

A method for estimating fish catch was developed for the evaluation of food provision in artificial tidal flats and seagrass beds. In artificial tidal flats, the biomass of fish and shellfish are present, but the fish catch is almost absent. In addition, the value of habitats for juvenile fishes, which is one of the important roles in seagrass beds...

Mangroves and seagrass have the potential of high climate change mitigation capacity. This capacity is governed by a series of processes: absorption of atmospheric CO2, fixation of absorbed carbon by biological production, and storage of fixed carbon in deep sediments, however, our knowledge concerned with these processes is still far from complete...

The effect of carbon storage by seagrass meadows has been recognized. In the present study, an attempt was made to create a Zostera japonica bed in the intertidal zone. Our results showed that eelgrass can grow and reproduce around the middle between Low Water Level and Mean Water Level even in the Keihin Canal where the water quality is not good....

Mangrove, seagrass, and coral habitats often lie adjacent to each other in the tropics and subtropics. Lateral carbon fluxes and their consecutive effects on CO2 dynamics and air–water fluxes along the ecosystem continuum are often overlooked. We measured the partial pressure of CO2 in water and associated biogeochemical parameters with a high temp...

Environmental DNA (eDNA) analysis allows information to be obtained about the identification of aquatic species. Seagrass DNA can be detected in sampled water which contains exocrine secretions from the fine pores on the leaf surface. We developed a seagrass monitoring method based on the eDNA analysis. The results show that the concentration of eD...

Aquatic models used for both freshwater and marine systems frequently need to account for submerged aquatic vegetation (SAV) due to its influence on flow and water quality. Despite its importance, parameterizations are generally adopted that simplify feedbacks from SAV, such as canopy properties (e.g., considering the deflected vegetation height) a...

Macroalgal beds have drawn attention as one of the vegetated coastal ecosystems that act as atmospheric CO2 sinks. Although macroalgal metabolism as well as inorganic and organic carbon flows are important pathways for CO2 uptake by macroalgal beds, the relationships between macroalgal metabolism and associated carbon flows are still poorly underst...

Submerged aquatic vegetation (SAV) such as seagrass alters hydrodynamics as a drag force. Many studies have investigated the SAV drag force, but the time scales studied have been short (several days to a few weeks), ignoring seasonal variation, and the spatial scales have been small (several meters). Here, we performed field research and developed...

Plain Language Summary Sandy beaches of open ocean coasts comprise one third of the ice‐free coastlines on Earth, but we know little about organism‐environment interactions in this setting. This study shows that there is a negative relationship between the number of filter‐feeding shrimp in seafloor sediments of the nearshore zone and the abundance...

The utilization of environmental DNA(eDNA) is being considered as a new method for monitoring seagrass beds. To understand the change in eDNA corresponding to seasonal variations in seagrass, the growth of Zostera marina inhabiting inside a water tank along with the amount of eDNA were investigated for fifteen months. Furthermore, investigations we...

Abstract. Macroalgal beds have drawn attention as one of the vegetated coastal ecosystems that act as atmospheric CO₂ sinks. Although macroalgal metabolism as well as inorganic and organic carbon flows are important pathways for CO₂ sequestration by macroalgal beds, the relationships between macroalgal metabolism and associate...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Globally, water bodies adjacent to mangroves are considered sources of atmospheric CO2. We directly measured the partial pressure of CO2 in water, pCO2(water), and other related biogeochemical parameters with very high (1-min) temporal resolution at Dhanchi Island in India’s Sundarbans during the post-monsoon season. We used elemental, stable isoto...

The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the fie...

浅海生態系における気候変動の緩和機能（大気中二酸化炭素（CO2）の吸収機能や生態系内への炭素貯留機能）が注目され始めているものの，その全国推計例はない．そこで本研究では，気候変動に関する政府間パネル（IPCC）のガイドラインに倣い，生態系内の炭素貯留量の増加量を大気中CO2の吸収量と定義し，国内外の既往文献をベースにデータ解析した．そして，我が国の浅海生態系（海草藻場，海藻藻場，マングローブ，干潟）における年間CO2吸収量の全国推計を試みた．その結果，現状におけるCO2吸収量の平均値は132万トンCO2/年，上限値は404万トンCO2/年と見積もられた．このような現状値あるいは将来値の推計を進めていくことは，地球温暖化対策計画における吸収源対策に浅海生態系を新たに定める検討や，浅海生態系の価...

Calcium carbonates (CaCO3) often accumulate in mangrove and seagrass sediments. As CaCO3 production emits CO2, there is concern that this may partially offset the role of Blue Carbon ecosystems as CO2 sinks through the burial of organic carbon (Corg). A global collection of data on inorganic carbon burial rates (Cinorg, 12% of CaCO3 mass) revealed...

Because coastal habitats store large amounts of organic carbon (Corg), the conservation and restoration of these habitats are considered to be important measures for mitigating global climate change. Although future sea‐level rise is predicted to change the characteristics of these habitats, its impact on their rate of Corg sequestration is highly...

Wetlands, tidal flats, seaweed beds, and coral reefs are valuable not only as habitats for many species, but also as places where people interact with the sea. Unfortunately, these areas have declined in recent years, so environmental improvement projects to conserve and restore them are being carried out across the world. In this study, we propose...

Location of survey stations for benthic organisms in four tidal flats: (a) SN, (b) UK,(c) TR, and (d) OR. (d) source: aerial photograph of Geospatial Information Authority of Japan, https://mapps.gsi.go.jp/.

Definition of variables for calculating wave run up height.

Conceptual model of environmental factors for environmental education.

Radarchart of PR4 scores for each environmental factor in environmental education: (a) SN, (b) UK, (c) TR, and (d) OR.

Conceptual model of environmental factors for historical designation as special sites.

Conceptual model of environmental factors for places for rest and relaxation.

Conceptual model of environmental factors for suspended material removal.

Radar chart of PR8 scores for each environmental factor in suspended material removal: (a) SN, (b) UK, (c) TR, and (d) OR.

Number of visitors per day by usage type.

Location of survey stations for bivalves in four tidal flats: (a) SN, (b) UK, (c) TR, and (d) OR. (d) source: aerial photograph of Geospatial Information Authority of Japan, https://mapps.gsi.go.jp/.

Conceptual model of environmental factors for carbon storage in benthic organisms.

Conceptual model of environmental factors for carbon storage in sediment.

Meanannual wet weights of commercially important species (X1; g-wet/m2) and presentstatus (x1) values forfood provision.

Scores for each tidal flat for research. Present status (x5), trend score (T5), PR score (PR5), likely near-term future status (x5,F), service score (I5), and sustainability score (S5).

Number of everyday users per day (V, people/day), total duration of everyday use adjusted by an awareness factor (X7) and present status (x7) values for places foreveryday rest and relaxation.

Scores for each tidal flat for everyday rest and relaxation. Present status (x7), trend score (T7), PR score (PR7), likely near-term future status (x7,F), service score (I7), and sustainability score (S7).

Environmental factors for suspended material removal.

Annualmean of bivalve water filtration volume (X8; m3/m2/h) and present status (x8) values for suspended material removal.