Sanae Chiba

North Pacific Marine Science Organization (PICES)

Marine ecosystems are continuously subjected to anthropogenic environmental pollution. Understanding the spread of pollution and the potential risks it poses to deep-sea ecosystems is important for developing better conservation measures. Here, we identified non-negligible levels of persistent organic pollutants in deep-sea chemosynthetic bivalves...

Maintaining healthy, productive ecosystems in the face of pervasive and accelerating human impacts including climate change requires globally coordinated and sustained observations of marine biodiversity. Global coordination is predicated on an understanding of the scope and capacity of existing monitoring programs, and the extent to which they use...

Global ocean physical and chemical trends are reviewed and updated using seven key ocean climate change indicators: (i) Sea Surface Temperature, (ii) Ocean Heat Content, (iii) Ocean pH, (iv) Dissolved Oxygen concentration (v) Arctic Sea Ice extent, thickness, and volume (vi) Sea Level and (vii) the strength of the Atlantic Meridional Overturning Ci...

Macroecological relationships provide insights into rules that govern ecological systems. Bergmann's rule posits that members of the same clade are larger at colder temperatures. Whether temperature drives this relationship is debated because several other potential drivers covary with temperature. We conducted a near‐global comparative analysis on...

The ocean provides essential services to human wellbeing through climate regulation, provision of food, energy and livelihoods, protection of communities and nurturing of social and cultural values. Yet despite the ocean’s key role for all life, it is failing as a result of unsustainable human practices. The first global integrated assessment of th...

KEYNOTE POINTS 1. Understanding of the ocean continues to improve. Innovations in sensors andautonomous observation platforms have substantially increased observations of the ocean. Regional observation programmes have expanded, with better coordination and integration. 2. Some responses for mitigating or reducing pressures and their associated...

KEYNOTE POINTS 1. Innovations in technology and engineering regarding sensors and autonomous observation platforms have substantially increased observations of the ocean and allowed for those observations to be collected at finer temporal and spatial resolutions. 2.The networking and coordination of regional observation programmes has been promote...

KEYNOTE POINTS 1. The purpose of the second World Ocean Assessment is to update the first World Ocean Assessment by providing an understanding of changes that have occurred in the global ocean since 2010 and associated trends. 2. The Assessment also provides an overview of understanding of some aspects not fully covered in the first Assessment, s...

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...

KEYNOTE POINTS 1. Extreme climate events. Marine heatwaves and tropical cyclones are shown to be increasing in severity owing to human activities and are having an impact on nature and human societies. Extreme El Niño events have been observed but, because they occur infrequently, a human influence has not been detected. All three phenomena are pr...

The abyss (3500–6500 m) covers the bulk of the deep ocean floor yet little is known about the extent of plastic debris on the abyssal seafloor. Using video imagery we undertook a quantitative assessment of the debris present on the abyssal seafloor (5700–5800 m depth) beneath the Kuroshio Extension current system in the Northwest Pacific. This body...

The seafloor covers some 70% of the Earth's surface and has been recognized as a major sink for marine litter. Still, litter on the seafloor is the least investigated fraction of marine litter, which is not surprising as most of it lies in the deep sea, i.e. the least explored ecosystem. Although marine litter is considered a major threat for the o...

The deep-sea is considered to be an ultimate sink for marine plastic debris. The abyssal (3500-6500 m) covers the bulk of the deep ocean floor yet little is known about the extent of plastic debris on the abyssal seafloor. We undertook a quantitative assessment of debris presents on the abyssal seafloor (5700-5800 m depth) beneath the Kuroshio Exte...

Classic niche theory assumes that species-level functional traits affect species relative fitness and thus community structuring, but empirical tests of this assumption are scarce. Moreover, recent evidence shows increasing functional over-redundancy towards the tropics, suggesting that the extent to which functional traits confer species' fitness...

Development of global ocean observing capacity for the biological EOVs is on the cusp of a step-change. Current capacity to automate data collection and processing and to integrate the resulting data streams with complementary data, openly available as FAIR data, is certain to dramatically increase the amount and quality of information and knowledg...

Plankton are the base of marine food webs, essential to sustaining fisheries and other marine life. Continuous Plankton Recorders (CPRs) have sampled plankton for decades in both hemispheres and several regional seas. CPR research has been integral to advancing understanding of plankton dynamics and informing policy and management decisions. We des...

In 2004, the United Nations (UN) General Assembly approved a Regular Process to report on the environmental, economic and social aspects of the world’s ocean. The Regular Process for Global Reporting and Assessment of the State of the Marine Environment, including Socioeconomic Aspects produced the first global integrated assessment of the marine e...

Impermanence is an ecological principle¹ but there are times when changes occur nonlinearly as abrupt community shifts (ACSs) that transform the ecosystem state and the goods and services it provides². Here, we present a model based on niche theory³ to explain and predict ACSs at the global scale. We test our model using 14 multi-decadal time serie...

The trait‐based approach is increasingly used in plankton ecology to understand diversity, community dynamics, and biogeography. While on the global scale phytoplankton traits are fairly well established, zooplankton traits are only beginning to be understood. One taxa‐transcending aspect of zooplankton diversity is the distinction between ambush a...

Developing enduring capacity to monitor ocean life requires investing in people and their institutions to build infrastructure, ownership, and long-term support networks. International initiatives can enhance access to scientific data, tools and methodologies, and develop local expertise to use them, but without ongoing engagement may fail to have...

Oceanographers have an increasing responsibility to ensure that the outcomes of scientific research are conveyed to the policy-making sphere to achieve conservation and sustainable use of marine biodiversity. Zooplankton monitoring projects have helped to increase our understanding of the processes by which marine ecosystems respond to climate chan...

Measurements of the status and trends of key indicators for the ocean and marine life are required to inform policy and management in the context of growing human uses of marine resources, coastal development, and climate change. Two synergistic efforts identify specific priority variables for monitoring: Essential Ocean Variables (EOVs) through th...

Sustained observations of marine biodiversity and ecosystems focused on specific conservation and management problems are needed around the world to effectively mitigate or manage changes resulting from anthropogenic pressures. These observations, while complex and expensive, are required by the international scientific, governance and policy commu...

This study reports plastic debris pollution in the deep-sea based on the information from a recently developed database. The Global Oceanographic Data Center (GODAC) of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) launched the Deep-sea Debris Database for public use in March 2017. The database archives photographs and videos o...

The changes related to interdecadal climate variations, such as the Pacific Decadal Oscillation and the 18.6-y tidal cycle, have been discussed in many marine ecosystem studies. The climate regime shift of 1976/77 played an important role in both lower and higher trophic ecosystem change, especially in the North Pacific. By analyzing data from obse...

We used more than 25,000 nutrient samples to elucidate for the first time basin-scale distributions and seasonal changes of surface ammonium (NH4⁺) and nitrite (NO2⁻) concentrations in the Pacific Ocean. The highest NH4⁺, NO2⁻, and nitrate (NO3⁻) concentrations were observed north of 40°N, in the coastal upwelling region off the coast of Mexico, an...

Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtaine...

Antarctic krill (Euphausia superba) and salps are major macroplankton contributors to Southern Ocean food webs and krill are also fished commercially. Managing this fishery sustainably, against a backdrop of rapid regional climate change, requires information on distribution and time trends. Many data on the abundance of both taxa have been obtaine...

To examine seasonal changes in the mesozooplankton community, analyses were made on the swimmer samples (>1 mm) collected by a sediment trap mooring at 184 m depth on the Northwind Abyssal Plain in the western Arctic Ocean during October 2010–September 2011. The zooplankton swimmer flux ranged from 5 to 44 ind. m−2 day−1 and was greater during July...

Spatial and temporal variation in copepod community structure, abundance, distribution and biodiversity were examined in the western subarctic North Pacific (40–53°N, 144–173°E) during 2001–2013. Continuous Plankton Recorder (CPR) observational data during the summer season (June and July) were analyzed. The latitudinal distribution of warm-water s...

The global distribution of zooplankton community structure is known to follow latitudinal temperature gradients: larger species in cooler, higher latitudinal regions. However, interspecific relationships between temperature and size in zooplankton communities have not been fully examined in terms of temporal variation. To re-examine the relationshi...

Regime shifts are characterized by sudden, substantial and temporally persistent changes in the state of an ecosystem. They involve major biological modifications and often have important implications for exploited living resources. In this study, we examine whether regime shifts observed in 11 marine systems from two oceans and three regional seas...

To examine seasonal changes in the mesozooplankton community, analyses were made on the swimmer samples (>1 mm) collected by a sediment trap mooring at 184 m depth on the Northwind Abyssal Plain in the western Arctic Ocean during October 2010–September 2011. The zooplankton swimmer flux ranged from 5 to 44 ind. m−2 day−1 and was greater during July...

Thee goal of the Pacific Ocean Boundary Ecosystem Climate Study (POBEX) was to diagnose the large-scale climate controls on regional transport dynamics and lower-trophic marine ecosystem variability in Pacific Ocean boundary systems. An international team of collaborators shared observational and eddy-resolving modeling datasets in the Northeast Pa...

The goal of the Pacific Ocean Boundary Ecosystem and Climate Study (POBEX) was to diagnose the large-scale climate controls on regional transport dynamics and lower trophic marine ecosystem variability in Pacific Ocean boundary systems. An international team of collaborators shared observational and eddyresolving modeling data sets collected in the...

Progress in oceanographic research in the past decade is reviewed and future directions and required infrastructures in the Japanese oceanographic research in the next decade are discussed, mainly from the biological oceanographic perspective. Particularly, we chose "Biodiversity" as the best keyword representing the nature of biological oceanograp...

1] We studied decadal-scale climate control of zooplankton biogeography driven by Kuroshio Extension (KE) dynamics using long-term zooplankton data and an advection model driven with currents from the Earth Simulator eddy-resolving ocean model. Passive tracer model experiments indicated that warm-water species transported from the south were retain...

The Kuroshio and Oyashio, western boundary currents in the North Pacific, greatly influence climate, ecosystems, and fisheries in the westernNorth Pacific and its adjacent waters. The Kuroshio/Oyashio ecosystem (KOE) shows interannual and decadal variability including regime shifts. Under a collaboration of the Climate Forcing and Marine Ecosystem...

We explored interannual variations and regional differences in abundance patterns and the timing of developmental events in the dominant copepods Eucalanus bungii, Neocalanus flemingeri, Neocalanus plumchrus and Neocalanus cristatus in the western North Pacific Ocean using Continuous Plankton Recorder survey data collected in the period 2001–2009....

Phytoplankton phenology and community structure in the western North Pacific were investigated for 2001-2009, based on satellite ocean colour data and the Continuous Plankton Recorder survey. We estimated the timing of the spring bloom based on the cumulative sum satellite chlorophyll a data, and found that the Pacific Decadal Oscillation (PDO)-rel...

Marine zooplankton must deal with seasonal variations of the upper-ocean environment that are both intense and prolonged compared to their life spans. This leads to large seasonal fluctuations of population size, and strong evolutionary tuning of demographic processes (e.g. reproduction, somatic and population growth, and dormancy) for optimal matc...

Keister, J. E., Bonnet, D., Chiba, S., Johnson, C. L., Mackas, D. L., and Escribano, R. 2012. Zooplankton population connections, community dynamics, and climate variability. – ICES Journal of Marine Science, 69: 347–350.

At the base of the marine foodweb, the free floating plant life of the sea (phytoplankton) provide food for the animal plankton (zooplankton) which in turn provide food for many other marine organisms. The carrying capacity of marine ecosystems in terms of the size of fish resources and recruitment to individual stocks as well as the abundance of m...

[1] We investigated phenological changes in phytoplankton in the subarctic North Pacific and the relationship to climatic forcing variability from 1998 to 2006, using ocean color satellite data combined with climatological data. The interannual to 9‐year mean variability in the timing, magnitude, and duration of phytoplankton blooms were examined u...

Temporal variation in the wintertime diatom community structure in Tokyo Bay was investigated from 1981 to 2000 with respect to possible environmental influences. A previous study found that rapid industrialization around the 1960s altered the diatom community. We found that a similar eutrophic-type community with low species diversity dominated by...

Temperature is a powerful correlate of large-scale terrestrial and marine diversity patterns but the mechanistic links remain unclear. Whilst many explanations have been proposed, quantitative predictions that allow them to be tested statistically are often lacking. As an important exception, the metabolic theory of ecology (MTE) provides a rather...

We have investigated the relationships between covariations in environmental variables and variations in distributions of marine copepod diversity over an extensive latitudinal range from 86.5uN to 46.5uS. For this purpose, 7 data sets (representing 13,713 samples) of copepod species composition data and 11 environmental data sets were assembled. P...

Advances in sampling and observation are described including new optical and acoustical systems together with animal tagging and telemetry. Shipboard, laboratory, and in situ studies of zooplankton feeding, reproduction and development, zooplankton and larval fish growth, and zooplankton mortality are reviewed. The relation between individual zoopl...