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Long-term biological time series that monitor ecosystems across the ocean’s full water column are extremely rare. As a result, classic paradigms are yet to be tested. One such paradigm is that variations in coastal upwelling drive changes in marine ecosystems throughout the water column. We examine this hypothesis by using data from three multidecadal time series spanning surface (0 m), midwater (200 to 1,000 m), and benthic (~4,000 m) habitats in the central California Current Upwelling System. Data include microscopic counts of surface plankton, video quantification of midwater animals, and imaging of benthic seafloor invertebrates. Taxon-specific plankton biomass and midwater and benthic animal densities were separately analyzed with principal component analysis. Within each community, the first mode of variability corresponds to most taxa increasing and decreasing over time, capturing seasonal surface blooms and lower-frequency midwater and benthic variability. When compared to local wind-driven upwelling variability, each community correlates to changes in upwelling damped over distinct timescales. This suggests that periods of high upwelling favor increase in organism biomass or density from the surface ocean through the midwater down to the abyssal seafloor. These connections most likely occur directly via changes in primary production and vertical carbon flux, and to a lesser extent indirectly via other oceanic changes. The timescales over which species respond to upwelling are taxon-specific and are likely linked to the longevity of phytoplankton blooms (surface) and of animal life (midwater and benthos), which dictate how long upwelling-driven changes persist within each community.

International audience; In the relatively unproductive waters of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity that sustain upper trophic levels, including fish that are crucial to the survival of islands' inhabitants. This phenomenon, termed the island mass effect 66 years ago, has been widely described. However, most studies focused on individual islands, and very few documented phytoplankton community composition. Consequently, basin-scale impacts on phytoplankton biomass, primary production and biodiversity remain largely unknown. Here we systematically identify enriched waters near islands from satellite chlorophyll concentrations (a proxy for phytoplankton biomass) to analyse the island mass effect for all tropical Pacific islands on a climatological basis. We find enrichments near 99% of islands, impacting 3% of the tropical Pacific Ocean. We quantify local and basin-scale increases in chlorophyll and primary production by contrasting island-enriched waters with nearby waters. We also reveal a significant impact on phytoplankton community structure and biodiversity that is identifiable in anomalies in the ocean colour signal. Our results suggest that, in addition to strong local biogeochemical impacts, islands may have even stronger and farther-reaching ecological impacts.

Coastal ecosystems are rapidly changing due to human-caused global warming, rising sea level, changing circulation patterns, sea ice loss, and acidification that in turn alter the productivity and composition of marine biological communities. In addition, regional pressures associated with growing human populations and economies result in changes in infrastructure, land use, and other development; greater extraction of fisheries and other natural resources; alteration of benthic seascapes; increased pollution; and eutrophication. Understanding biodiversity is fundamental to assessing and managing human activities that sustain ecosystem health and services and mitigate humankind’s indiscretions. Remote-sensing observations provide rapid and synoptic data for assessing biophysical interactions at multiple spatial and temporal scales and thus are useful for monitoring biodiversity in critical coastal zones. However, many challenges remain because of complex bio-optical signals, poor signal retrieval, and suboptimal algorithms. Here, we highlight four approaches in remote sensing that complement the Marine Biodiversity Observation Network (MBON). MBON observations help quantify plankton functional types, foundation species, and unique species habitat relationships, as well as inform species distribution models. In concert with in situ observations across multiple platforms, these efforts contribute to monitoring biodiversity changes in complex coastal regions by providing oceanographic context, contributing to algorithm and indicator development, and creating linkages between long-term ecological studies, the next generations of satellite sensors, and marine ecosystem management.

Our synthesis combines inferences from a long-term fisheries monitoring survey and principles of ecosystem oceanography to inform and benefit biodiversity monitoring and modeling studies within the California Current Large Marine Ecosystem. We review the history, research, and application of the Rockfish Recruitment and Ecosystem Assessment Survey, highlighting how one survey of life can illuminate understanding of pelagic biodiversity patterns and ecosystem function (from micronekton to top predators to ecosystem services) that may be easily extended to other surveys to strengthen observation networks. Biodiversity is often used as the standard for understanding ecosystem resilience to climate or anthropogenic disturbances. This concept is central to our review, and we examine it in relation to complex impacts resulting from a recent climate event (a marine heatwave) on biodiversity, ecosystem function, and socioeconomic services. We present a system of interconnected modules that summarize and illustrate patterns of pelagic biodiversity using a phylogenetic approach, known modulations and environmental drivers of variability (i.e., source waters, habitat compression, and ecosystem shifts), remote sensing and modeling tools for monitoring biodiversity (i.e., seascapes and krill hotspot models), and the status of top predator biodiversity. We use these modules to summarize connections between biodiversity and ecosystem services provided. Following each module, a brief discussion of questions raised and recommendations for future studies and partnerships is provided to improve future integrative biodiversity monitoring. Additionally, we invested in promoting data accessibility and outreach, resulting in several data visualization and ecosystem context tools for biodiversity monitoring and fisheries management. We advocate that a diverse integrated ecosystem approach should result in fewer ecological surprises by putting past events and surprises into context, and thus better anticipating those yet to arrive. Building partnerships among researchers and coastal communities will result in increased capacity of analytical tools and perspectives to ensure sustainable use of fishery resources, while strengthening the resilience of fishing communities.

In the California Current Ecosystem, krill represent a key link between primary production and higher trophic level species owing to their central position in the food web and tendency to form dense aggregations. However, the strongly advective circulation associated with coastal upwelling may decouple the timing, occurrence, and persistence of krill hotspots from phytoplankton biomass and nutrient sources. Results from a coupled physical‐biological model provide insights into fundamental mechanisms controlling the phenology of krill hotspots in the California Current Ecosystem, and their sensitivity to alongshore changes in coastal upwelling intensity. The simulation indicates that dynamics controlling krill hotspot formation, intensity, and persistence on seasonal and interannual timescales are strongly heterogeneous and related to alongshore variations in upwelling‐favorable winds, primary production, and ocean currents. Furthermore, regions promoting persistent krill hotspot formation coincide with increased observed abundance of top predators, indicating that the model resolves important ecosystem complexity and function., Key Points Krill hotspot formation and persistence are strongly heterogeneous in space and timeKrill hotspots are shaped by local upwelling variability and regional circulationKrill hotspots coincide with observed distributions of marine mammals and seabirds

In oligotrophic gyres of the tropical ocean, islands can enhance phytoplankton biomass and create hotspots of productivity and biodiversity. This “Island Mass Effect” (IME) is typically identified by increased chlorophyll concentrations next to an island. Here we use a simple plankton model in a Lagrangian framework to represent an unexplained open ocean bloom, demonstrating how islands could have triggered it remotely. This new type of IME, termed “delayed IME”, occurs when nitrate is limiting, N:P ratios are low, and excess phosphate and iron remain in water masses after an initial bloom associated to a “classical” IME. Nitrogen fixers then slowly utilize leftover phosphate and iron while water masses get advected away, resulting in a bloom decoupled in time (several weeks) and space (hundreds of km) from island‐driven nutrient supply. This study suggests that the fertilizing effect of islands on phytoplankton may have been largely underestimated. Plain language summary In the poor and nutrient‐depleted waters of the tropical Pacific, islands act as sources of nutrients fertilizing nearby waters. These nutrients are consumed by microscopic photosynthesizing algae, the phytoplankton. The resulting phytoplankton enrichments (blooms) in turn support productive ecosystems. This phenomenon, termed the “island mass effect”, has been known for sixty years and is classically defined by increased chlorophyll (representing phytoplankton biomass) next to an island. Blooms also occur in the open ocean and are usually attributed to vertical processes such as mixing or uplifting that locally supply nutrients from subsurface reservoirs. In this paper, we demonstrate that a different type of island mass effect exists, where the phytoplankton response is delayed because they grow very slowly. These blooms are supported by the nitrogen fixer Trichodesmium. Since phytoplankton get carried away from islands by oceanic currents while they grow, this can lead to a bloom located hundreds of km away with no apparent connection to the islands. Nutrient inputs by islands followed by advection can thus trigger remote blooms in the open ocean. Our study suggests that the fertilizing effect of islands may currently be largely underestimated, particularly in the warm waters of the tropical Pacific where Trichodesmimum is common.

Studies of marine physical, chemical, and microbiological processes benefit from observing in a Lagrangian frame of reference. Some of these processes are related to specific density or temperature ranges. We have developed a method for a Tethys-class long-range autonomous underwater vehicle (LRAUV) (which has a propeller and a buoyancy engine) to track a targeted isothermal layer (within a narrow temperature range) in a stratified water column when operating in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. The LRAUV starts on an initial descent to search for the target temperature. Once the temperature falls in the target center bracket, the vehicle records the corresponding depth and adjusts buoyancy to hold that depth. As long as the temperature stays within a tolerance range, the vehicle continues to hold that depth. If the temperature falls out of the tolerance range, the vehicle will increase or decrease buoyancy to reacquire the target temperature and track it. In a June 2015 experiment in Monterey Bay, CA, USA, an LRAUV ran the presented algorithm to successfully track a target isotherm for 13 h. Over the isotherm tracking duration, the LRAUV mostly remained in the 0.5 $^\circ $ C (peak-to-peak) tolerance range as designed, even though the water column's stratification kept changing. This work paves the way to coupling an LRAUV's complimentary modes of flight and drift—searching for an oceanographic feature in flight mode, and then switching to drift mode to track the feature in a Lagrangian frame of reference.

International audience; High-resolution autonomous sensors routinely measure physical (temperature, salinity), chemical (oxygen, nutrients) and biological (fluorescence) parameters. However, while fluorescence provides a proxy for phyto-plankton, heterotrophic populations remain challenging to monitor in real-time and at high resolution. Bathyphotometers, sensors which measure the light emitted by bioluminescent organisms when mechanically stimulated, provide the capability to identify bioluminescent dinoflagellates and zooplankton. In the coastal ocean, highly abundant dinoflagellates emitting low-intensity flashes generate a background bioluminescence signal, while rarer zooplankton emit bright flashes that can be individually resolved by high-frequency sensors. Bathyphotometers were deployed from ships and onboard autonomous underwater vehicles (AUVs) during three field campaigns in Monterey Bay, California. Ship-based in situ water samples were simultaneously collected and the plankton communities characterized. Plankton concentrations were matched with concurrent datasets of fluorescence and bioluminescence to develop proxies for autotrophic and heterotrophic dinoflagellates, other phytoplankton such as diatoms, copepods, larvaceans (appendicularians), and small jellies. The method extracts the bioluminescence background as a proxy for dinoflagellates, and exploits differences in bioluminescence flash intensity between several types of zooplankton to identify larvaceans, copepods and small jellies. Fluorescence is used to discriminate between autotrophic and heterotrophic dinoflagellates, and to identify other autotrophic plankton. Concurrent fluorometers and bathyphotometers onboard AUVs can thus provide a novel view of plankton diversity and phytoplankton/zooplankton interactions in the sea.

Significance Ignoring temporal fluctuations in the oceanic carbon budget leads to a significant misrepresentation of the cycling of organic matter from production in surface waters to consumption and sequestration in the abyssal ocean. A 29-year time series (1989 to 2017) of particulate organic carbon (POC) fluxes and sea-floor measurements of sediment community oxygen consumption (SCOC) revealed episodic, high-magnitude events over the past 7 years. Time lags between changes in satellite-estimated export flux, POC flux and SCOC varied from 0 to 70 days. A commonly used model to estimate carbon flux through the water column significantly underestimated the measured carbon fluxes by almost 50%. Episodic pulses of organic carbon into the deep sea must be accounted for to balance the oceanic carbon budget., Growing evidence suggests substantial quantities of particulate organic carbon (POC) produced in surface waters reach abyssal depths within days during episodic flux events. A 29-year record of in situ observations was used to examine episodic peaks in POC fluxes and sediment community oxygen consumption (SCOC) at Station M (NE Pacific, 4,000-m depth). From 1989 to 2017, 19% of POC flux at 3,400 m arrived during high-magnitude episodic events (≥mean + 2 σ), and 43% from 2011 to 2017. From 2011 to 2017, when high-resolution SCOC data were available, time lags between changes in satellite-estimated export flux (EF), POC flux, and SCOC on the sea floor varied between six flux events from 0 to 70 days, suggesting variable remineralization rates and/or particle sinking speeds. Half of POC flux pulse events correlated with prior increases in EF and/or subsequent SCOC increases. Peaks in EF overlying Station M frequently translated to changes in POC flux at abyssal depths. A power-law model (Martin curve) was used to estimate abyssal fluxes from EF and midwater temperature variation. While the background POC flux at 3,400-m depth was described well by the model, the episodic events were significantly underestimated by ∼80% and total flux by almost 50%. Quantifying episodic pulses of organic carbon into the deep sea is critical in modeling the depth and intensity of POC sequestration and understanding the global carbon cycle.

International audience; Satellite observations of wind, sea level and derived currents, sea surface temperature (SST), and chlorophyll are used to expand our understanding of the physical and biological variability of the ocean surface north of New Guinea. Based on scarce cruise and mooring data, previous studies differentiated a trade wind situation (austral winter) when the New Guinea Coastal Current (NGCC) flows northwestward and a northwest monsoon situation (austral summer) when a coastal upwelling develops and the NGCC reverses. This circulation pattern is confirmed by satellite observations, except in Vitiaz Strait where the surface northwestward flow persists. We find that intraseasonal and seasonal time scale variations explain most of the variance north of New Guinea. SST and chlorophyll variabilities are mainly driven by two processes: penetration of Solomon Sea waters and coastal upwelling. In the trade wind situation, the NGCC transports cold Solomon Sea waters through Vitiaz Strait in a narrow vein hugging the coast. Coastal upwelling is generated in westerly wind situations (westerly wind event, northwest monsoon). Highly productive coastal waters are advected toward the equator and, during some westerly wind events, toward the eastern part of the warm pool. During El Niño, coastal upwelling events and northward penetration of Solomon Sea waters combine to influence SST and chlorophyll anomalies.

Deep-sea fields of polymetallic nodules in the Clarion-Clipperton Zone (CCFZ, tropical NE Pacific) are currently being investigated to assess their potential for commercial mining. During such mining, benthic communities will be inevitably disturbed or destroyed. Therefore, assessments of their standing stock and composition may be helpful for the future evaluation of possible impacts of commercial nodule exploitation. Analysis of nematode communities (at genus level) inhabiting the French license area of the CCFZ were studied based on data from the cruises NODINAUT (2004) and BIONOD (2012). The total nematode density was ca. 1.5-fold higher in 2012 as compared with 2004. This reflected a 2–2.5 times higher density of non-selective deposit-feeders (i.e. possessing a small buccal cavity without armature) in 2012 compared with 2004, whereas no significant differences between sampling periods were observed in the density of the other feeding groups. Consequently, whilst the list of the most abundant genera was identical, their relative abundances changed significantly. The relative abundance of the genus Thalassomonhystera was two times greater in 2012 than in 2004, whereas the relative abundances of the genera Acantholaimus and Theristus were significantly lower in 2012 (10% and 4%, respectively) than in 2004 (28% and 9%). Nematode diversity (including values of diversity indices and total number of recorded genera) was significantly lower in 2012 in comparison with 2004. Although our data do not take into account seasonal and shorter temporal scales of variability in nematode assemblages, we report here that a certain fraction of variations observed between the two sampling periods could be associated with differences in primary production. Future studies should aim to better characterise temporal variability in nematode communities of the CCFZ at seasonal and interannual scales.

The regulation of seasonal satellite-derived primary production (PP) was investigated within a 150 km coastal box in four eastern boundary upwelling systems (EBUS): California, Peru, Northwest Africa and Benguela. The following regulating factors were considered: (1) wind-driven nitrate supply; (2) iron supply inferred from proxies (shelf mud belt width, modeled atmospheric iron deposition, river discharge); (3) temperature; (4) light and (5) physical export consisting of offshore export, eddy-driven and wind-driven subduction. The ratio of potential new production (carbon-equivalent of nitrate supply) to primary production, termed the N-ratio, is shown to be an indicator of PP limitation by nitrate supply (low N-ratios) vs. inhibition by other factors (high N-ratios). The factors regulating PP were assessed by analyzing the N-ratios and computing spatial correlations between PP and each factor each month. The regulation of primary production was found to vary spatially, seasonally and from one EBUS to another. Macronutrient supply is shown to be the dominant regulating factor off Northwest Africa and during some seasons and locations in other systems. Light regulation within the mixed layer occurs in all EBUS in winter but may only inhibit PP (high N-ratios) off Peru and Benguela. Evidence for iron limitation was found in each EBUS (except Northwest Africa) at varying levels and was greatest off Peru during austral winter when iron demand by phytoplankton increases due to low light levels. Rapid offshore advection combined with wind-driven and/or eddy-driven subduction may inhibit PP off California. A simple generalization regarding the regulation of primary production in EBUS is not forthcoming.

Since its founding, the Monterey Bay Aquarium Research Institute (MBARI) has pioneered unique capabilities for accessing the deep ocean and its inhabitants through focused peer relationships between scientists and engineers. This focus has enabled breakthroughs in our understanding of life in the sea, leading to fundamental advances in describing the biology and the ecology of open-ocean and deep-sea animals. David Packard’s founding principle was the application of technological advances to studying the deep ocean, in part because he recognized the critical importance of this habitat in a global context. Among other fields, MBARI’s science has benefited from applying novel methodologies in molecular biology and genetics, imaging systems, and in situ observations. These technologies have allowed MBARI’s bioluminescence and biodiversity laboratory and worldwide collaborators to address centuries-old questions related to the biodiversity, behavior, and bio-optical properties of organisms living in the water column, from the surface into the deep sea. Many of the most interesting of these phenomena are in the midwater domain—the vast region of ocean between the sunlit surface waters and the deep seafloor.

The biological response in the western equatorial Pacific Ocean during El Nino/La Nina transitions and the underlying physical mechanisms were investigated. A chlorophyll a bloom was observed near the Gilbert Islands during the 2010 El Nino/La Nina transition, whereas no bloom was observed during the 2007 El Nino/La Nina transition. Compared to the previously observed bloom during the 1998 El Nino/La Nina transition, the 2010 bloom was weaker, lagged by 1-2 months, and was displaced eastward by similar to 200 km. Analysis suggested that the occurrence, magnitude, timing, and spatial pattern of the blooms were controlled by two factors: easterly winds in the western equatorial Pacific during the transition to La Nina and the associated island mass effect that enhanced vertical processes (upwelling and vertical mixing), and the preconditioning of the thermocline depth and barrier layer thickness by the preceding El Nino that regulated the efficiency of the vertical processes. Despite the similar strength of easterly winds in the western equatorial Pacific during the 1998 and 2010 transitions to La Nina, the 20092010 El Nino prompted a deeper thermocline and thicker barrier layer than the 1997-1998 El Nino that hampered the efficiency of the vertical processes in supplying nutrients from the thermocline to the euphotic zone, resulting in a weaker bloom.

[1] Synchrony in the second modes of an empirical orthogonal function (EOF) analysis of global physical and biological properties is described for the 1993–2010 time period. High correlations are found between the El Nino Modoki index and principal component time series of sea surface temperature, sea surface salinity, photosynthetically active radiation, precipitation, surface currents, surface chlorophyll concentration, and equatorial temperature profiles. Spatial patterns indicate that the second mode is also associated with the North Pacific Gyre Oscillation (NPGO). Biological changes during traditional El Ninos (first EOF mode) have been explained on the basis of strong and coherent variations in thermocline depth, wind-driven upwelling and light, but changes associated with the second mode are more subtle and complex. Equatorial temperature profiles indicate that the warming is confined to the mixed layer and that changes in thermocline depth are small. The biological changes associated with the second mode may be driven by a combination of weak perturbations to vertical nutrient supply and the strength of subtropical gyres. In the western tropical Pacific, the site of some of the strongest perturbations, the biological changes can be associated with the occurrence and thickness of barrier layers and to island effects downstream of the Kiribati Islands. Globally integrated impacts of the second mode are much weaker than those associated with the traditional ENSO. During the positive phase, chlorophyll is strongly enhanced in the tropics and weakly enhanced at the global scale in sharp contrast to traditional El Nino effects. The analysis improves our understanding of global-scale physical and biological coupling associated with the so-called El Nino Modoki and the NPGO.

[1] Improvements in fisheries and ecosystem management could be made if the prediction of key zooplankton, such as krill, were possible using ocean ecosystem models. To examine structural realism, hence the validity of a coupled physical-biogeochemical model, we compared measured spatiotemporal dynamics of krill and seabird abundance off California to hindcasted mesozooplankton derived from an independently designed model. Observed krill and modeled mesozooplankton (Z2) displayed latitudinal coherence but distinct longitudinal offsets, possibly related to unrealistic bathymetry in the model. Temporally, Z2, Thysanoessa spinifera (a neritic krill species) and seabird density and reproductive performance were well correlated, indicating that quantitative prediction regarding marine predators in upwelling ecosystems is within reach. Despite its basin-scale framework, the ROMS-CoSiNE model captures zooplankton and top predator dynamics regionally in the central California region, suggesting its utility for management of marine ecosystems and highlighting rapid advances that can be made through collaboration between empirical scientists and ecosystem modelers.

We extend existing oceanographic sampling methodologies to sample an advecting feature of interest using autonomous robotic platforms. GPS-tracked Lagrangian drifters are used to tag and track a water patch of interest with position updates provided periodically to an autonomous underwater vehicle (AUV) for surveys around the drifter as it moves with ocean currents. Autonomous sampling methods currently rely on geographic waypoint track-line surveys that are suitable for static or slowly changing features. When studying dynamic, rapidly evolving oceanographic features, such methods at best introduce error through insufficient spatial and temporal resolution, and at worst, completely miss the spatial and temporal domain of interest. We demonstrate two approaches for tracking and sampling of advecting oceanographic features. The first relies on extending static-plan AUV surveys (the current state-of-the-art) to sample advecting features. The second approach involves planning of surveys in the drifter or patch frame of reference. We derive a quantitative envelope on patch speeds that can be tracked autonomously by AUVs and drifters and show results from a multi-day off-shore field trial. The results from the trial demonstrate the applicability of our approach to long-term tracking and sampling of advecting features. Additionally, we analyze the data from the trial to identify the sources of error that affect the quality of the surveys carried out. Our work presents the first set of experiments to autonomously observe advecting oceanographic features in the open ocean.

A century-long EOF analysis of global sea surface temperature (SST) was carried out and the first six modes, independent by construction, were found to be associated with well-known regional climate phenomena: the El Niño–Southern Oscillation (ENSO), the Atlantic multidecadal oscillation (AMO), the Pacific decadal oscillation (PDO), the North Pacific Gyre Oscillation (NPGO), El Niño Modoki, and the Atlantic El Niño. Four of the six global modes are dominated by Pacific changes, the other two (M2 and M6) being associated with the AMO and Atlantic El Niño, respectively. The principal component time series of the ENSO (M1) and North Pacific (M3) modes are coherent at time scales >10 yr, and their interaction results in the traditional PDO pattern and the dominant mode of Pacific multidecadal variability. The M3 and PDO time series are well correlated, but the EOFs have different spatial patterns. The fourth mode (M4) has been strengthening since the 1950s and is related to the NPGO but also to El Niño Modoki, especially at the decadal scale. The fifth global mode (M5) is also spatially and temporally correlated to El Niño Modoki. The Pacific SST modes are further related to atmospheric forcing and the circulation of the North Pacific subpolar and subtropical gyres.

Coastal upwelling along eastern boundaries has fascinated oceanographers for decades. The strong coupling between atmospheric forcing, ocean circulation, biogeochemical cycling, and food web dynamics encouraged oceanographers to conduct multidisciplinary scientific studies that have since become common. Following that tradition, an interdisciplinary approach is taken to highlight differences between the major Eastern Boundary Upwelling Ecosystems (EBUE’s). Ocean basin-scale settings are important determinants of EBUE characteristics. First, trade winds accumulate heat and mass in the western side of the basins, deepening the thermocline in the west and raising it in the east. Second, and especially prominent in the Pacific, these properties are redistributed eastwards on interannual and multidecadal time scales, reducing the characteristically high biological productivity found in the eastern basin margins. Thirdly, north–south patterns of thermocline doming on the equator and deepening in the subtropical gyres, and high latitude weather-driven mixing makes latitude an important characteristic of each EBUE. As such each EBUE has 3–4 well-defined latitudinally distributed biomes. Many enigmas remain regarding EBUE’s including: (1) Why do EBUE’s differ dramatically in fish but not in primary production? (2) What nutrients or other physical properties limit EBUE primary production? (3) What roles do subsurface oxygen minimum zones play in EBUE ecosystems? (4) What role do euphausiids play in the transfer of energy through EBUE food webs? (5) What are the roles of EBUE food webs in the biogeochemical cycling of elements? (6) How inter-connected are biomes of EBUE ecosystems? and (7) Most importantly for society, how will EBUE’s respond to climate and global change.

Nitrate supply by coastal upwelling has been estimated for four eastern boundary regions (Benguela, California, Northwest Africa and Peru) by combining surface winds measured from space and in situ vertical nitrate profiles. We use a QuikSCAT 0.25 ° × 0.25 ° weekly wind product to assess the seasonal vertical transport induced by wind forcing. The calculation is made from the coast to 150 km offshore and the wind-driven upwelling is partitioned into that contributed by Ekman transport and pumping. We assume that on the upwelling event time scale (days) the water brought to the surface originates from a depth of 60 m. Seasonal climatologies are used to estimate in situ nitrate concentration at 60 m, and nitrate supply is calculated as the product of nitrate concentration times the vertical transport obtained from QuikSCAT. This represents the potential new production, i.e. the amount of nitrate available for phytoplankton primary production, for each region. We find that Benguela, Northwest Africa and Peru have similar levels of nitrate supply and potential new production while California has about 60% of the other three.

Long-term observing of our world's oceans is crucial to understanding climate change. Innovation and collaboration are needed to achieve sustainable oceanic time series.

Studying ocean processes often requires observations made in a Lagrangian frame of reference, that is, a frame of reference moving with a feature of interest [1]. Often, the only way to understand a process is to acquire measurements at sufficient spatial and temporal resolution within a specific feature while it is evolving. Examples of coastal ocean features whose study requires Lagrangian observations include concentrated patches of microscopic algae (Fig. 1) that are toxic and may have impacts on fisheries, marine life and humans, or a patch of low-oxygen water that may cause marine life mortality depending on its movement and mixing.

We have designed, built, tested and fielded a decision support system which provides a platform for situational awareness, planning, observation, archiving and data analysis. While still in development, our inter-disciplinary team of computer scientists, engineers, biologists and oceanographers has made extensive use of our system in at-sea experiments since 2010. The novelty of our work lies in the targeted domain, its evolving functionalities that closely tracks how ocean scientists are seeing the evolution of their own work practice, and its actual use by engineers, scientists and marine operations personnel. We describe the architectural elements and lessons learned over the more than two years use of the system.

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We also acknowledge Coriolis (http://www.coriolis.eu.org), AVISO (http://www.aviso.oceanobs.com/duacs), the CERSAT (http://cersat.ifremer.fr), OSCAR (http://www.oscar.noaa.gov), and RSS (http://www.ssmi.com), for sharing the freely available data we used. We are grateful to Thierry Delcroix for constructive discussions during this work We thank three anonymous reviewers for their very valuable remarks. This work was supported by CNES (Ocean Surface Topography Science Team program). F. L benefited from CNES funding. 1 ELSEVIER SCIENCE INC NEW YORK REMOTE SENS ENVIRON; The analysis of the SeaWiFS chlorophyll archive shows a quasi-persistent strip of oligotrophic waters (chl < 0.1 mg m(-3)) extending over about 20 degrees longitude in the eastern part of the equatorial Pacific warm pool. Other space-borne data sets (scatterometric wind, microwave sea surface temperature (SST), altimetric sea level, and surface currents) were used together with barrier layer thickness derived from Argo floats to investigate the variability of the oligotrophic zone and of its eastern and western boundaries, and to propose processes that could explain why surface chlorophyll is so low in this region. The eastern limit of the oligotrophic waters matches the eastern edge of the warm pool and moves zonally both at seasonal time scale and with the El Nino/La Nina phases whereas the western limit moves mostly at intraseasonal and interannual time scales. On average, about half of the surface of the zone is occupied by very oligotrophic waters (chl < 0.07 mg m(-3)) located in the eastern part. The degree of oligotrophy of the zone increases when its width is maximum during boreal fall and winter and during El Nino events. Oligotrophy in the eastern part of the warm pool most likely persists because of the lack of vertical or horizontal penetration of nutrient-rich water due to the following processes. 1/ The equatorial oligotrophic warm pool is bounded poleward by the oligotrophic subtropical gyres. 2/The deep nutrient pool prevents strong vertical nutrient inputs into the euphoric layer and the barrier layer above it potentially reduces the efficiency of mixing. 3/ During westerly wind events, mesotrophic waters in the far western basin are too distant from the oligotrophic zone to be efficient nutrient and phytoplankton sources, and become nutrient and phytoplankton depleted during their eastward advection. 4/ Nutrient-rich waters from the central basin and nutrient-poor surface waters of the warm pool do not blend because of subduction at the eastern limit of the oligotrophic zone.

[1] A global-scale Empirical Orthogonal Function (EOF) analysis of physical (sea surface temperatures, sea level height anomalies, atmospheric sea level pressure, photosynthetically active radiation, zonal surface currents and wind-driven upwelling velocities) and biological (surface chlorophyll concentrations and primary production) variables shows synchronous variations from 1993 to 2010 in the first mode of variability associated with El Nino Southern Oscillation (ENSO). The first EOF of vertical temperature structure along the equatorial Pacific shows identical temporal patterns. The ENSO-driven biological changes are explained both qualitatively and quantitatively from a subset of the physical variables. During the strong 1997–1998 El Nino a global new production decrease of ∼0.6–0.9 PgC yr−1is estimated from changes in the depth of the nutricline and wind-driven upwelling. This is consistent with the 3.0 PgC yr−1decrease in global primary production observed by satellite remote sensing. A simple two-layer model of chlorophyll and primary production driven by changes in nitrate and light reproduces the patterns and magnitude of changes observed by satellite. Changes in the depth of the nutricline are found to be the primary driver of the biological anomalies. The ENSO mode of zonal currents in the equatorial Pacific shows that horizontal advection is responsible for changes in chlorophyll in the central Pacific not explained by the two-layer model.

With the advent of Autonomous Underwater Vehicles (AUVs) and other mobile platforms, marine robotics have had substantial impact on the oceanographic sciences. These systems have allowed scientists to collect data over temporal and spatial scales that would be logistically impossible or prohibitively expensive using traditional ship-based measurement techniques. Increased dependence of scientists on such robots has permeated scientific data gathering with future field campaigns involving these platforms as well as on entire infrastructure of people, processes and software, on shore and at sea. Recent field experiments carried out with a number of surface and underwater platforms give clues to how these technologies are coalescing and need to work together. We highlight one such confluence and describe a future trajectory of needs and desires for field experiments with autonomous marine robotic platforms. Our 2010 inter-disciplinary experiment in the Monterey Bay involved multiple platforms and collaborators with diverse science goals. One important goal was to enable situational awareness, planning and collaboration before, during and after this large-scale collaborative exercise. We present the overall view of the experiment and describe an important shore-side component, the Oceanographic Decision Support System (ODSS), its impact and future directions leveraging such technologies for field experiments.

Marine photosynthetic plankton are responsible for approximately 50 petagrams (1015) of carbon per year of net primary production, an amount equivalent to that on land. This primary production supports essentially all life in the oceans and profoundly affects global biogeochemical cycles and climate. This review discusses the general distribution of primary production in the sea, the processes that regulate this distribution, and how marine primary production is sensitive to climate variability and change. Statistical modes of ocean variability and their characteristic interannual to multi-decadal timescales over the last century are described. Recent in situ and satellite time-series of primary production can be clearly linked to interannual ocean variability. Global marine primary production appears to have increased over the past several decades in association with multi-decadal variations. A paleoclimate record extends discussion to the centennial scale, providing contrasting insights into how marine primary production might vary in the future.

Cuvelier, Marie L. ... et al.-- 6 pages, 4 figures, 1 table, this article contains supporting information online at https://www.pnas.org/content/pnas/suppl/2010/07/27/1001665107.DCSupplemental/pnas.201001665SI.pdf.-- Data deposition: The sequences reported in this paper have been deposited in the Gen-Bank database (accession nos. HM581528–HM581638 and HM565909–HM565914). Other scaffolds with predicted genes from this Whole Genome Shotgun/454 project have been deposited at DNA Data Bank of Japan/European Molecular Biology Laboratory/GenBank under the accession no. AEAR00000000. The version described in this paper is the first version, AEAR01000000, Among eukaryotes, four major phytoplankton lineages are responsible for marine photosynthesis; prymnesiophytes, alveolates, stramenopiles, and prasinophytes. Contributions by individual taxa, however, are not well known, and genomes have been analyzed fromonly the latter two lineages. Tiny >picoplanktonic> members of the prymnesiophyte lineage have long been inferred to be ecologically important but remain poorly characterized. Here, we examine pico-prymnesiophyte evolutionary history and ecology using cultivation-independent methods. 18S rRNA gene analysis showed picoprymnesiophytes belonged to broadly distributed uncultivated taxa. Therefore, we used targeted metagenomics to analyze uncultured pico-prymnesiophytes sorted by flow cytometry from subtropical North Atlantic waters. The data reveal a composite nuclear-encoded gene repertoire with strong green-lineage affiliations, which contrasts with the evolutionary history indicated by the plastid genome. Measured pico-prymnesiophyte growth rates were rapid in this region, resulting in primary production contributions similar to the cyanobacterium Prochlorococcus. On average, pico-prymnesiophytes formed 25% of global picophytoplankton biomass, with differing contributions in five biogeographical provinces spanning tropical to subpolar systems. Elements likely contributing to success include high gene density and genes potentially involved in defense and nutrient uptake. Our findings have implications reaching beyond pico-prymnesiophytes, to the prasinophytes and stramenopiles. For example, prevalence of putative Ni-containing superoxide dismutases (SODs), instead of Fe-containing SODs, seems to be a common adaptation among eukaryotic phytoplankton for reducing Fe quotas in low-Fe modern oceans. Moreover, highly mosaic gene repertoires, although compositionally distinct for each major eukaryotic lineage, now seem to be an underlying facet of successful marine phytoplankton, Sequencing was under DE-AC02- 05CH11231, by a Department of Energy Community Sequencing Program award to A.Z.W. and J. Eisen. Support was in part by DE-FC02-02ER63453, NSF OCE-0722374, and NSF-MCB-0732448 (to A.E.A.); a National Human Genomic Research Institute, National Institutes of Health grant (to R.S.L.); National Oceanic and Atmospheric Administration and David and Lucile Packard Foundation (DLPF) grants (F.P.C.); NSF-OCE-0241740 (to B.J.B.); and major funding by NSF-OCE-0836721, the DLPF, and a Moore Foundation Young Investigator Award as well as Moore 1668 (to A.Z.W.). Author contribution details are given in SI Materials and Methods, Section 12

During the transition between El Nino and La Nina conditions in 1998, a dramatic bloom occurred near the equator around 170 degrees E, with chlorophyll concentrations reaching more than 0.8 mg m(-3) in May. Previous studies attributed this bloom to a wind-driven upwelling and to the shoaling of the Equatorial Undercurrent (EUC), but they did not explain its particular location near the Kiribati Islands. By combining simulations with observations, we determined that these islands were able to locally disrupt the physical dynamics and the nutrient fields to the extent that they were directly responsible for the location and the amazing strength of the bloom. Our results suggest that an island mass effect was responsible for generating the bloom, while the barrier formed by the islands increased EUC shoaling to the west of them, which explained the bloom peak.

International audience; We used Sea-viewing Wide Field-of-view Sensor (SeaWiFS) to document the seasonal cycle of surface chlorophyll in the western tropical Pacific. Surface waters in this region can be divided into two ecosystems. The western end of the cold, salty waters of the cold tongue with high nutrient low chlorophyll (HNLC) characteristics occupies most of the eastern part Of the region, while warm, fresh, and oligotrophic waters of the warm pool stand in the western part. Nevertheless, disruption of the oligotrophy may show up at different locations. We reconstructed the seasonal cycle of chlorophyll, sea surface temperature (SST), winds, and surface currents from satellite data and satellite-derived products by extracting the annual and semi-annual harmonics of the time series at each grid point. The calculation was done for the 1999-2004 years in order to exclude the consequences of the major 1997-1998 El Nino Southern Oscillation event. The variance explained by the seasonal cycle for this period highlights three regions with high seasonality: (1) The oligotrophy/HNLC transition zone undergoes meridional seasonal displacements. The cold tongue is at its northernmost (southernmost) position during boreal spring (fall). These displacements can be explained in terms of meridional advection of chlorophyll-rich waters and are consistent with the seasonal cycle of the north and south equatorial countercurrents that transport phytoplankton-poor waters. (2) Ocean-color images show seasonal enrichments in the far western north equatorial countercurrent (NECC) area, especially during boreal spring. The chlorophyll maximum coincides with the maximum NECC velocity, follows a SST minimum, and occurs during the upwelling-favorable phase of the wind stress curl. We attribute these enrichments to local upwelling associated with current meandering, horizontal advection from further west, and transport of nutrient-rich waters by the New Guinea coastal undercurrent. (3) Near the Solomon Archipelago, we observe enhancements of chlorophyll concentration southwest of the islands in austral winter, when both the southwestward surface currents and the southeasterly wind stress are strongest. This may be a combination of an island-mass effect and wind-driven upwelling. Horizontal advection from the Solomon area leads to an almost concurrent seasonal chlorophyll enrichment in the northern Coral Sea. In the Gulf of Papua, high chlorophyll concentrations at the same time can be explained by the presence of a strong cyclonic circulation. This study highlights the richness of the response of surface chlorophyll to physical processes at the seasonal time scale in a region usually acknowledged as oligotrophic.