Coastal upwelling

This study reports hydrographic and biological observations from three cruises where cyclonic and anticyclonic eddies were observed downstream of Gran Canaria island. Based on field data and remote sensing images (AVHRR and CZCS), two mechanisms associated with islandgenerated eddies, largely responsible for the formation and distribution of chlorophyll around the Canary Islands, are proposed. First, nutrient pumping and vertical uplifting of the deep chlorophyll maximum by cyclonic eddies might represent important sources of primary production in the oligotrophic waters of the Canary region. Second, eddies are responsible for the horizontal transport and distribution of chlorophyll originating near the islands or off the African coast. Water with high chlorophyll content, resulting from island stirring or local upwelling at the flanks of the islands, is incorporated into cyclonic eddies in their development and subsequently transported downstream. On the other hand, anticyclonic eddies can also entrain water rich in chlorophyll when interacting with the offshore boundary of the African coastal upwelling. This chlorophyll will be advected southward as the eddy drifts. The recurrence of cyclonic and anticyclonic eddies, together with the presence of upwelling filaments throughout the year, must have important biological consequences in the formation and transport of organic matter in the Canary region. 0 1997

The abundance and several estimators of mesozooplankton biomass (dry weight, ash-free dry weight, displacement volume, carbon and nitrogen) were measured in a coastal upwelling area off La Coruna (NW Spain) at monthly intervals between 1990 and 1995. Holoplanktonic copepods dominated in most of the samples, but meroplankton were also important near the coast, especially during late spring and through summer. Gelatinous organisms (medusae, siphonophores and larvaceans) reached significant abundances (-10%) in shelf waters by late summer, but also near the coast in spring. Log-linear equations were computed between dry weight, displacement volume and the other biomass estimators, to allow for interconversion among different measurements. To prevent the influence of meroplankton and gelatinous zooplankton in the estimations of biomass, the equations were adjusted using only samples in which the abundance of each of these groups was <10% of total individuals. Our equations produced carbon and ash-free dry weight estimates that are comparable to those obtained with the ratios given in other studies in the region. However, the estimations of mesozooplankton carbon from displacement volume using the adjusted equation with our data are lower than those reported previously for the area, which were computed using equations adjusted with data from a different ecosystem. The use of interconversion factors taken from the literature is discussed, along with the implications of the estimations of mesozooplankton biomass in the computations of the flux of carbon through the ecosystem. © Oxford University Press 1005 by guest on December 25, 2012 http://plankt.oxfordjournals.org/ Downloaded from by guest on December 25, 2012 http://plankt.oxfordjournals.org/ Downloaded from

Observations of the tropical atmosphere are fundamental to the understanding of global changes in air quality, atmospheric oxidation capacity and climate, yet the tropics are under-populated with long-term measurements. The first three years (October 2006–September 2009) of meteorological, trace gas and particulate data from the global WMO/Global Atmospheric Watch (GAW) Cape Verde Atmospheric Observatory Humberto Duarte Fonseca (CVAO; 16° 51′ N, 24° 52′ W) are presented, along with a characterisation of the origin and pathways of air masses arriving at the station using the NAME dispersion model and simulations of dust deposition using the COSMO-MUSCAT dust model. The observations show a strong influence from Saharan dust in winter with a maximum in super-micron aerosol and particulate iron and aluminium. The dust model results match the magnitude and daily variations of dust events, but in the region of the CVAO underestimate the measured aerosol optical thickness (AOT) because of contributions from other aerosol. The NAME model also captured the dust events, giving confidence in its ability to correctly identify air mass origins and pathways in this region. Dissolution experiments on collected dust samples showed a strong correlation between soluble Fe and Al and measured solubilities were lower at high atmospheric dust concentrations. Fine mode aerosol at the CVAO contains a significant fraction of non-sea salt components including dicarboxylic acids, methanesulfonic acid and aliphatic amines, all believed to be of oceanic origin. A marine influence is also apparent in the year-round presence of iodine and bromine monoxide (IO and BrO), with IO suggested to be confined mainly to the surface few hundred metres but BrO well mixed in the boundary layer. Enhanced CO2 and CH4 and depleted oxygen concentrations are markers for air-sea exchange over the nearby northwest African coastal upwelling area. Long-range transport results in generally higher levels of O3 and anthropogenic non-methane hydrocarbons (NMHC) in air originating from North America. Ozone/CO ratios were highest (up to 0.42) in relatively fresh European air masses. In air heavily influenced by Saharan dust the O3/CO ratio was as low as 0.13, possibly indicating O3 uptake to dust. Nitrogen oxides (NOx and NOy) show generally higher concentrations in winter when air mass origins are predominantly from Africa. High photochemical activity at the site is shown by maximum spring/summer concentrations of OH and HO2 of 9 × 106 molecule cm−3 and 6 × 108 molecule cm−3, respectively. After the primary photolysis source, the most important controls on the HOx budget in this region are IO and BrO chemistry, the abundance of HCHO, and uptake of HOx to aerosol.

An organic-walled dinoagellate cyst analysis was carried out on 53 surface sediment samples from West Africa (17-6°N) to obtain insight in the relationship between their spatial distribution and hydrological conditions in the upper water column as well as marine productivity in the study area. Multivariate analysis of the dinoagellate cyst relative abundances and environmental parameters of the water column shows that sea-surface temperature, salinity, marine productivity and bottom water oxygen are the factors that relate signicantly to the distribution patterns of individual species in the region. The composition of cyst assemblages and dinoagellate cyst concentrations allows the identication of four hydrographic regimes; 1) the northern regime between 17 and 14°N characterized by high productivity associated with seasonal coastal upwelling, 2) the southern regime between 12 and 6°N associated with high-nutrient waters inuenced by river discharge 3) the intermediate regime between 14 and 12°N inuenced mainly by seasonal coastal upwelling additionally associated with uvial input of terrestrial nutrients and 4) the offshore regime characterized by low chlorophyll-a concentrations in upper waters and high bottom water oxygen concentrations. Our data show that cysts of Polykrikos kofoidii, Selenopemphix quanta, Dubridinium spp., Echinidinium species, cysts of Protoperidinium monospinum and Spiniferites pachydermus are the best proxies to reconstruct the boundary between the NE trade winds and the monsoon winds in the subtropical eastern Atlantic Ocean. The association of Bitectatodinium spongium, Lejeunecysta oliva, Quinquecuspis concreta, Selenopemphix nephroides, Trinovantedinium applanatum can be used to reconstruct past river outow variations within this region.

This paper reviews relevant investigations conducted in the Western Iberia Upwelling Ecosystem (WIUE) on the dynamics of small pelagic fish (SPF), its relationship to climate changes and processes related to the 'ocean triad' (enrichment, concentration, transport/retention). In the last decades, a decline in the productivity of several SPF species (e.g., sardine and horse mackerel) was observed in the WIUE, which is partially explained by environmental variability (e.g., changes in coastal upwelling). The main mechanism proposed to explain this decline is the increased frequency and intensity of upwelling events during the spawning season (winter) of these species, which is typically a period when convergence conditions prevail. Thus, this 'anomalous' situation promotes egg and larval dispersal away from the favourable coastal habitat (the shelf) and consequently has a negative impact on their survival and recruitment. However, the variability of local features like the Western Iberia Buoyant Plume (WIBP) and the Iberian Poleward Current (IPC) introduce important fluctuations in the transport patterns of the region, and could modulate the impact of these winter upwelling events in the survival of larvae. The retention on the shelf of larval sardine along convergence zones formed by the interaction of these two features plays an important role in their survival. Furthermore, the WIBP is a suitable environment for the growth of phytoplankton and for larval fish survival. From these findings it is clear that simplified Ekman transport models could not explain larval fish transport/retention patterns in this region and more realistic biophysical models should be used to simulate the local oceanographic conditions to understand larval dynamics and the success of recruitment of SPF in the Western Iberia.

Transport from nutrient-rich coastal upwellings is a key factor influencing biological activity in surrounding waters and even in the open ocean. The rich upwelling in the NorthWestern African coast is known to interact strongly with the wake of the Canary islands, giving rise to filaments and other mesoscale structures of increased productivity. Motivated by this scenario, we introduce a simplified two-dimensional kinematic flow describing the wake of an island in a stream, and study the conditions under which there is a net transport of substances across the wake. For small vorticity values in the wake, it acts as a barrier, but there is a transition when increasing vorticity so that for values appropriate to the Canary area, it entrains fluid and enhances cross-wake transport.

The Benguela system is one of the four major eastern boundary upwelling systems of the world. It is unusual as there are two stratified subtropical or warm temperate boundary regions, on either side of the major wind-driven upwelling region(19-34°S), which itself is subdivided at 26°S by the powerful Luderitz upwelling cell. Important biological components cross the boundary areas at different stages to complete the life-history cycle. While the ''Bakun triad" of factors responsible for the development of large pelagic fish populations (enrichment, concentration and retention) provide an important unifying principle for understanding the compromise implicit in adaptation to upwelling systems, the role of predation has been neglected, as has the fish yield relative to photosynthesis. The role global climate change will have in the Benguela in terms of shifting boundaries or weakening or intensifying gradients is being explored. The interannual and decadal signals are so strong in the region that long term trends are difficult to distinguish. Intensive resource utilisation and the collapse of several fish stocks occurred in the Benguela region during the 1960s and 1970s, with different recovery trajectories in the north and the south. The Angolan subsystem can be described as a subtropical transition zone between the wind-driven upwelling system and the Equatorial Atlantic, with gentle upwelling-favourable winds, well-defined seasons, intermediate productivity and moderate, declining fisheries. It is separated from the Namibian subsystem by the Angola-Benguela front.

The Canary Current upwelling ecosystem (CanC) constitutes one of the four main eastern boundary upwelling ecosystems (EBUEs) of the world, thus hosting high productivity and fisheries. Recent observations indicate that the CanC region as a whole has been experiencing a progressive warming and a decrease in productivity over the last decades. This overall trend is however not directly reflected in the fisheries of the region. Here we update recent results and previous reviews on the CanC, covering aspects from the physical environment to fish populations and fisheries on a range of time scales. We approach these topics, when possible, through a comparative exploration of the biogeographical characteristics of different sub-regions comprising this ecosystem. This review shows that variability in coastline configuration, shelf width, coastal upwelling, nutrient fertilization, productivity, or retentive vs. dispersive physical mechanisms, among other factors, may help explain sub-regional differences in fish distributions and abundances in the CanC. Nevertheless, the lack of systematic information on the regional variability of physical and biological processes hampers an integrated understanding of the relative contribution of natural vs. human-induced variability in the populations of at least small-pelagic fishes and their associated fisheries.

In the Humboldt Current System (HCS), biological and non-biological components, ecosystem processes, and fisheries are known to be affected by multi-decadal, inter-annual, annual, and intra-seasonal scales. The interplay between atmospheric variability, the poleward undercurrent, the shallow oxygen minimum zone (OMZ), and the fertilizing effect of coastal upwelling and overall high primary production rates drive bio-physical interactions, the carbon biomass, and fluxes of gases and particulate and dissolved matter through the water column. Coastal upwelling (permanent and seasonally modulated off Peru and northern Chile, and markedly seasonal between 30°S and 40°S) is the key process responsible for the high biological productivity in the HCS.

Coastal upwelling ecosystems provide the bulk of the world's fishery yields, but the biochemical ecology of the species that make up these fisheries has, surprisingly, been ignored. Biochemical indicators can provide a mechanistic, ecosystem-based link between population and ecosystem dynamics. Here we investigated long-term, inter-annual changes in the proximate composition and energetic condition of European sardine Sardina pilchardus and its relationship with oceanographic conditions in the Western Iberian Upwelling Ecosystem. Energy density (ED) ranged between 4.0 and 14.2 kJ g -1 , and the seasonal cycle largely determined temporal variability, explaining > 80% of the observed variation. ED variations were also closely linked with water (total R 2 = 99.0% in whole body; total R 2 = 95.0% in muscle) and lipid dynamics (total R 2 = 99.6% in whole body; total R 2 = 92.5% in muscle). After adjusting for seasonality (rED) and restricting the temporal analysis to the end of the feeding period (August to October), spring/early-summer oceanographic conditions explained 67% of the late-summer energetic peak. Interestingly, the sardine rED peak in year (t) explained > 54.4% of the variation in the annual catches of year (t + 1), indicating that adult energetic condition during spawning is partially translated into the fishery through parental effects in recruitment strength. Our results support earlier findings indicating that sardine population dynamics seem to be controlled by bottom-up effects, but the linkages between population dynamics and patterns in environmental variability via physiological condition seem to have previously been overlooked. We also provide empirical evidence that biochemical assessments during critical periods of the life-cycle of fish are essential in understanding the population dynamics of coastal upwelling ecosystems and in developing a more solid basis for stock management and conservation.

The vertical mixing in the transition area from the North Sea to the Baltic Sea is dominated by entrainment processes of the inflowing saline water within near bottom layers. The hot spots of these processes are located at the Darss Sill and the Bornholm Channel in the western Baltic Sea. In the central Baltic Sea temporal changes and associated transports are dominated by the horizontal advection of saline water in deep layers below the permanent halocline. This is accompanied by the turbulent vertical transport through the halocline into the surface layers. The related vertical salt transport into the entire surface mixed layer is estimated by various methods to be around values slightly above 30 kg/(m² a). During so-called stagnation periods the corresponding residence time of the deep water in the Eastern Gotland Basin drastically increases roughly by a factor of five. Therefore vertical mixing through the halocline seems to be drastically reduced when inflows are lacking. The potential processes of diapycnal mixing are discussed to the present knowledge. The turbulent motion resulting from breaking internal waves seems to be capable of turbulent transports through the halocline corresponding to the estimates of the salt transport into the surface mixed layer. The actual knowledge about boundary mixing due to internal waves in the Baltic Sea is found to be poor. Mesoscale eddies are evaluated to be able to contribute to the vertical mixing, but it is not known if they really do and which of the possible direct and indirect mixing mechanisms is most effective. Near bottom currents induced by inflow events are found to be likely to enhance vertical mixing. Coastal upwelling certainly contributes to the vertical transport, but the depth of its origin and the volume transport are hard to determine for large-scale quantifications. The short spatiotemporal scale of turbulent transports through the halocline resulting in a weakening of the halocline during summer and the mixing of the entire surface layer down to the halocline in winter are combined to a consistent description of the vertical salt transport. The longer residence time of the deep water during stagnation periods is hypothesised to be attributed to the lack of energy imported by the inflows and directly or indirectly feeding the diapycnal mixing processes. The discussion about consequences of vertical mixing processes crossing the seasonal thermocline and affecting the embedded ecosystem arrives at the conclusion that the vertical transport of nutrients such as the phosphate is quantitatively not sufficiently understood and needs further interdisciplinary research activities.

Dissolved oxygen (DO) concentration in the water column is an environmental parameter that is crucial for the successful development of many pelagic organisms. Hypoxia tolerance and threshold values are species-and stagespecific and can vary enormously. While some fish species may suffer from oxygen values of less than 3 mL O 2 L −1 through impacted growth, development and behaviour, other organisms such as euphausiids may survive DO levels as low as 0.1 mL O 2 L −1 . A change in the average or the range of DO may have significant impacts on the survival of certain species and hence on the species composition in the ecosystem with consequent changes in trophic pathways and productivity.

Estimation of the terms in the upper-ocean heat budget from a moored array in the central Arabian Sea shows periods when a rough balance between the temperature trend and the horizontal advection of heat exists. Altimetry and sea-surface temperature imagery are used to demonstrate that these episodes of strong horizontal advection are associated with mesoscale features. During the wintertime Northeast (NE) Monsoon these are capped-off mesoscale eddy features generated during the previous summertime Southwest (SW) Monsoon and have little horizontal transport of heat within the mixed layer. During the SW Monsoon the major contribution is strong offshore export of coastally upwelled water in a filament with a strong surface presence. Temperature and salinity properties from the moored array and a SeaSoar survey during the formation of the coastal filament confirm the offshore transport of the upwelled water mass to the site of the moored array, more than 600 km offshore. Estimates of the filament section heat flux are several percent of the total estimated heat flux due to upwelling along the Arabian Peninsula, and remote sensing data show that similar mesoscale variability along the coast is enhanced during the SW Monsoon. This points to the importance of mesoscale-modulated transports in not only the observed heat budget at the moored array, but in the overall upperocean heat budget in the Arabian Sea. r

The Guinea Current Large Marine Ecosystem (GCLME) extending from Bissagos Island (Guinea Bissau) in the north to Cabinda (Angola) in the south defines the shared transboundary waters off the coast of western Africa, which embodies some of the major coastal upwelling sub-ecosystems of the world and is an important centre of marine biodiversity and marine food production. The GCLME is characterized by distinctive bathymetry, hydrography, chemistry, and trophodynamics and represents the number 28 Large Marine Ecosystem (LME) ranked among the most productive coastal and offshore waters in the world with rich fishery resources. However, over-exploitation of fisheries, pollution from domestic and industry sources, habitat destruction and poorly planned and managed coastal developments and near-shore activities are resulting in a rapid depletion of the rich fisheries resources and degradation of vulnerable coastal and offshore habitats putting the economies, productivity and health of the populace at risk. Recognizing the urgency of the fisheries decline and the environmental and socio-economic consequences for the region, the 16 countries bordering the ecosystem have mobilized complementary resources to the funding from the Global Environment Facility and United Nations Industrial Development Organization to implement priority management actions agreed in the preliminary Strategic Action Programme for the recovery of depleted fish stocks and restoration of degraded habitats for the advancement of the achievement of the World Summit on Sustainable Development (WSSD) Johannesburg Plan of Implementation targets for recovery of fish stocks.

RESUMEN. En este estudio se caracterizaron los patrones de circulación en el interior del Golfo de Arauco (37°10'S -36°45'S, Chile) que están asociados a períodos de intensificación y relajación de la surgencia costera durante un período de transición verano-otoño. Se analizaron imágenes satelitales de TSM (10, 16, 22 y 27 de marzo), series de corrientes (a 10 y 28 m) provenientes de tres fondeos de correntómetros y series de viento. Los resultados muestran que la marea semidiurna, las fluctuaciones diurnas del viento S-SW y los procesos de surgencia y de hundimiento en la plataforma adyacente al Golfo, son factores importantes en la determinación de la circulación al interior de éste. La discusión se centró en fluctuaciones del orden de tres a diez días identificándose, durante el período de estudio, 4 eventos de relajación (9-13, 19-20, 23-24, y 30-31 de marzo) y 4 de surgencia (2-8, 14-18, 21-22 y 25-29 de marzo) adyacentes al Golfo. El viento S-SW, favorable a surgencia, forzó una circulación antihoraria de una sola capa durante el máximo desarrollo de la surgencia. Durante viento N, en cambio, la circulación mostró una tendencia horaria durante procesos de hundimiento fuera del Golfo. En períodos de transición o debilitamiento del viento, ya sea de viento S-SW o N, la circulación mostró un sistema de doble capa: superficial antihoraria y subsuperficial horaria. Se propone un esquema conceptual de la circulación del Golfo de Arauco en períodos de Surgencia-Relajación basado en el patrón de circulación subinercial. Este patrón dependió, principalmente, de las fluctuaciones de la intensidad y dirección del viento y de la entrada de agua hacia el interior del Golfo a través de su "Boca Grande".

Las aguas del mar Caribe son pobres pero existen algunas áreas que contrastan notablemente y son moderadamente fértiles, como es el caso del nororiente de Venezuela donde se realiza una extracción pesquera de relativa importancia El enriquecimiento regional comúnmente se asocia con la surgencia de aguas subsuperficiales, fenómeno hidrográfico anual que ocurre durante /os primeros meses. Pero se ha planteado la existencia de otras causas que propician la fertilidad acuática durante todo el año, porque al sur de la isla de Margarita se verificó que la hidrografía, los nutrientes y el plancton tienen marcada estacionalidad entre los períodos de enero a mayo y de junio a diciembre, sin embargo los valores de producción primaria no tienen diferencia significativa. Los grandes ríos suramericanos (Orinoco y Amazonas) y las ondas internas causan enriquecimientos y también las lagunas costeras como La Restinga (isla de Margarita) eutrofican notablemente las aguas adyacentes durante los meses de mayo a noviembre, cuando es menos intenso o cesa el fenómeno del afloramiento de aguas. Estos componentes coadyuvan a la fertilidad marina regional, que propicia la existencia permanente de recursos pesqueros pelágicos como la sardina Sardinella aurita y recursos bentónicos como el molusco Arca zebra, entre otras especies de importancia económica regional y nacional. PALABRAS CLAVE / Ecología marina / Hidrografía / Venezuela / El mar Caribe generalmente tiene aguas pobres; sin embargo existen regiones donde se realizan extracciones pesqueras de relativa cuantía, como es el caso del nororiente de Venezuela, donde se captura más del 60% del total nacional. Esta producción pesquera tiene su origen en la moderada riqueza de las aguas, que permite la captura de especies con ciclo de vida corto, crecimiento rápido y hábitos alimenticios micrófagos como en la sardina venezolana Sardinella aurita (Clupeidae). En las zonas periféricas, la flota pesquera de media altura captura especies depredadoras (escómbridos, carángidos, corifénidos, lutjánidos y serránidos) que se alimentan de la sardina.

Flight dynamics theories are influenced by two major topics: how birds adapt their flight to cope with heterogeneous habitats, and whether birds plan to use the wind field or simply experience it. The aim of this study was to understand the flight dynamics of free-flying Cory's shearwaters in relation to the wind characteristics on the coastal upwelling region of continental Portugal. We deployed recently miniaturised devices-global positioning system loggers to collect precise and detailed information on birds' positions and motions. Prevalent winds were blowing from the north-east and adults used those winds by adjusting their flight directions mainly towards north-west and south-west, flying with cross and tail winds, respectively, and avoiding head winds. This is confirmation that Cory's shearwaters use a shear soaring flying strategy while exploiting the environment for food: adults foraged mainly with cross winds and their ground speed was not constant during all foraging trips as it changed dynamically as a result of the ocean surface shear winds. During travelling phases, ground speed was strongly influenced by the position of the bird with regard to the wind direction, as ground speed increased significantly with increasing tail wind component (TWC) values. Adults appear to choose foraging directions to exploit ambient wind, in order to improve shear soaring efficiency (cross winding) and exploit diurnal changes in tail wind strength to maximise commuting efficiency. We report, for the first time, precise ground speed values (GPS-derived data) and computed actual flight speed values (using TWC analysis) for Cory's shearwater.

Two sediment cores retrieved from the continental slope in the Benguela Upwelling System, GeoB 1706 (19°33.7'S 1 l°10.5'E) and GeoB 1711 (23°18.9'S, 12°22.6'E), reveal striking variations in planktonic foraminiferal abundances during the last 160,000 years. These fluctuations are investigated to assess changes in the intensity and position of the upwelling centres off Namibia. Four species make up over 95% of the variation within the core, and enable the record to be divided into episodes characterized by particular planktonic foraminiferal assemblages. The fossil assemblages have meaningful ecological significance when compared to those of the modern day and the relationship to their environment. The cold-water planktonic foraminifer, Neogloboquadrina pachyderma sinistral [N. pachyderma (s)], dominates the modern-day, coastal upwelling centres, and Neogloboquadrina pachyderma dextral and Globigerina bulloides characterize the fringes of the upwelling cells. Globorotalia inflata is representative of the offshore boundary between newly upwelled waters and the transitional, reduced nutrient levels of the subtropical waters. In the fossil record, episodes of high N. pachyderma (s) abundances are interpreted as evidence of increased upwelling intensity, and the associated increase in nutrients. The N. pachyderma (s) record suggests temporal shifts in the intensity of upwelling, and corresponding trophic domains, that do not follow the typical glacial-interglacial pattern. Periods of high N. pachyderma (s) abundance describe rapid, discrete events dominating isotope stages 3 and 2. The timing of these events correlates to the temporal shifts of the Angola-Benguela Front situated to the north of the Walvis Ridge. Absence of high abundances of N. pachyderma (s) from the continental slope of the southern Cape Basin indicates that Southern Ocean surface water advection has not exerted a major influence on the Benguela Current System. The coincidence of increased upwelling intensity with the movement of the Angola-Benguela Front can be interpreted mainly by changes in strength and zonality of the trade wind system.

This study analyzes the characteristics of upwelling events during the northeast monsoon, as
well as El-Niño impacts towards upwelling in the northwest Sabah, which is located in southern
part of the South China Sea by combining remote sensing, reanalysis, and modeling data. The
data used in this study obtained from Moderate Resolution Imaging Spectroradiometer (MODIS)
Aqua satellite for the sea surface temperature (SST) and chlorophyll a concentration data, Hybrid
Coordinate Ocean Model (HYCOM) for the vertical cross section of temperature and salinity
data, and European Centre for Medium-range Weather Forecast (ECMWF) Interim Reanalysis
(ERA-Interim) for the wind data, as well as Ekman transport and Ekman pumping analysis during
December to April 2003-2016. The monthly mean of the climatological data were analyzed and
the results showed that the MODIS-Aqua satellite indicates the presence of cooler sea surface
temperature (SST) and higher chlorophyll-a concentration along the inshore region of northwest
Sabah during the northeast monsoon, indicating the existence of upwelling. Cross-sectional
temperature profiles obtained from the HYCOM further confirmed the existence of upwelling as
the thermohaline was uplifted from the deeper layer and reached the surface during the northeast
monsoon. Ekman transport and Ekman pumping derived from the ECMWF showed an upwelling
favorable condition during the northeast monsoon. Comparison between climatological data and
El-Niño year in 2016 represented that El-Niño events somehow increase the upwelling intensity
due to the intensification of Ekman transport and Ekman pumping.

Seasonal coastal upwelling was analyzed along the NW African coastline (11-351N) from 1981 to 2012. Upwelling magnitudes are calculated by wind speed indices, sea-surface temperature indices and inferred from meteorological station, sea-surface height and vertical water column transport data. A permanent annual upwelling regime is documented across 21-351N and a seasonal regime across 12-191N, in accordance with the climatology of previous studies. Upwelling regions were split into three zones: (1) the Mauritania-Senegalese upwelling zone (12-191N), (2) the strong permanent annual upwelling zone (21-261N) and (3) the weak permanent upwelling zone (26-351N). We find compelling evidence in our various indices for the Bakun upwelling intensification hypothesis due to a significant coastal summer wind speed increase, resulting in an increase in upwelling-favorable wind speeds north of 201N and an increase in downwelling-favorable winds south of 201N. The North Atlantic Oscillation plays a leading role in modifying interannual variability during the other seasons (autumn-spring), with its influence dominating in winter. The East Atlantic pattern shows a strong correlation with upwelling during spring, while El Niño Southern Oscillation and Atlantic Multi-decadal Oscillation teleconnections were not found. A disagreement between observationally-based wind speed products and reanalysisderived data is explored. A modification to the Bakun upwelling intensification hypothesis for NW Africa is presented, which accounts for the latitudinal divide in summer wind regimes. Fig. 3. The monthly climatology (1981-2010) for the Mauritania-Senegalese upwelling zone (12-191N, blue line), permanent upwelling zone (21-261N, red line) and the weak permanent upwelling zone (26-351N, green line) for the seven UI W (units: m 3 s À 1 100 m À 1 ) and three UI ΔSST (units: 1C) indices. Error bars on the individual months highlight the (1s) monthly variability. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

The Southern Brazilian Bight (SBB) is a large semi-enclosed marine ecosystem which stands as one of the most productive coastal regions of Brazil, supporting more than 20% of Brazilian industrial fisheries. Primary production is sustained by the upwelling of the cold and nutrient rich South Atlantic Central Water during the austral summer, provided by a seasonal meteorologically controlled upwelling system, coupled with the frequent development of eddies from Brazil's Current. Many of the exploited fish species spend their planktonic stages confined within the SBB dependencies. The paper brings out some evidences about possible El Niño/La Ninã teleconnections and their possible effects over the oceanographic regime and biological productivity; and therefore, over the living resource dynamics of the studied area. Among these evidences are the modifications detected in the community structure of benthic fishes at an upwelling "hot-spot" (Arraial do Cabo), as well as the fluctuations of the Brazilian sardine catches, which seem to be in phase with intense El Niño events. New evidences are presented through a Hovmoller temperature diagram which shows the presence of cold waters over the SBB's shelf during the 1982/83 El Ninõ/La Niña, contrasting with the less intense 1986/87 phenomenon.

Ocean circulation and temperature in the Indochinese Peninsula (IP) are dominated by
the monsoon. The monsoon currents are seasonally reversing open-ocean currents
flowing between the west Pacific Ocean into the South China Sea and the north Indian
Ocean into the Bay of Bengal. The ocean mixing of overflows from marginal seas is a
key process shaping the structure of ocean upwelling and circulation. This study
explored the dynamic elements of the Sea Surface Temperature (SST) and coastal
upwelling in the IP using the AVHRR-SST and the Regional Oceanic Modeling
System (ROMS). The ROMS model is used to simulate the regional ocean scales in
the IP in response to atmospheric fields forced by wind stress from the QuickSCAT
(1999-2009), surface fluxes global monthly climatology (COADS05) with the finer
resolution of SST (9.28 km) from the AVHRR-Pathfinder, global river flow and
continental discharge monthly climatology, tidal data from the Oregon State
University (TPXO7), and the World Ocean Atlas 2009 dataset. The ocean simulation
results on climatological scale were compared with the Large-McWilliams-Doney KP
profile and the Generic Length Scale (GLS) vertical mixing schemes during monsoon
seasons. The simulated SST fields were verified against the AVHRR-SST. Both
schemes were analyzed to characterize the variability and trends of coastal upwelling
in the region. The results confirmed the presence of reversing current system in
response to the changing wind field: the eastward flowing southwest ocean current during the southwest monsoon, and the westward flowing northeast ocean current
during the northeast monsoon. These results indicated that the observed SST trends
were not only due to changes in the radiation or atmospheric heat fluxes but also due
to changes in upwelling dynamics, suggesting that the process may be relevant in
climate change scenarios. The results also suggested that the best vertical mixing
parameterization was the GLS scheme.

Birds and mammals are important components of pelagic marine ecosystems, but our knowledge of their foraging ecology is limited. We distinguish six distinct types of data that can be used in various combinations to understand their foraging behavior and ecology. We describe methods that combine concurrent dive recorder deployment, oceanographic sampling, and hydroacoustic surveys to generate hypotheses about interactions between the physical environment and the distribution, abundance, and behavior of pelagic predators and their prey. Our approach is to (1) map the distribution of whales in relation to the distribution of their prey and the physical features of the study area (bottom topography, temperature, and salinity); and (2) measure the foraging behavior and diet of instrumented whales in the context of the fine-scale distribution and composition of their prey and the physical environment. We use this approach to demonstrate a relationship between blue whale distribution, sea surface temperature, and concentrations of their euphausiid prey at different spatial scales offshore of the Channel Islands, California. Blue whale horizontal spatial distribution was correlated with regions of high acoustic backscatter. Blue whale dive depths closely tracked the depth distribution of krill. Net sampling and whale diet revealed that whales fed exclusively upon dense schools of Euphausia pacifica (between 100 and 200 m) and ¹hysanoessa spinifera (from the surface to 100 m). Whales concentrated foraging efforts upon those dense euphausiid schools 0967-0645/98/$ -see front matter 1998 Elsevier Science Ltd. All rights reserved. PII: S 0 9 6 7 -0 6 4 5 ( 9 8 ) 0 0 0 3 1 -9 that form downstream from an upwelling center in close proximity to regions of steep topographic relief. We propose that (1) the distribution of Balaenoptera whales in the coastal California Current region is defined by their attraction to areas of predictably high prey density;

The accumulation of biogeochemical (organic carbon, calcium carbonates, molybdenum and iodine), micropalaeontological (benthic foraminifera) and terrigenous markers (grain-size, Si=Al, Zr=Al, K=Al) over the last 70,000 years in one core (Sedorqua-11K) on the northwest African margin off Cap Blanc has been used to reconstruct past variations of local upwelling intensity and oceanic productivity. The study demonstrates that productivity in this area increased during Stage 3, particularly between 40,000 and 50,000 yr B.P., and during the last deglaciation between 6000 and 15,000 yr B.P. During most of isotopic Stage 2, and particularly during the last glacial maximum, productivity was much lower. These variations can be attributed to changes in local wind stress and seasonality that are related to variability in monsoon pressure intensity. Because of the establishment of upwelling cells over the shelf due to high sea-level, the conditions of sedimentation during the last 5-6 thousend years on the upper slope (site 11K) are largely dominated by advection from the shelf, leading to strong sorting prior to deposition. Advection seems to have been minor during the other periods of enhanced productivity. A conceptual model is proposed to link the productivity variations to atmospheric circulation, in particular to the wind stress, direction and seasonality.

Long-term data characterizing the oceans' biological carbon pump are essential for understanding impacts of climate variability on marine ecosystems. The "Bakun upwelling intensification hypothesis" suggests intensified coastal upwelling due to a greater land-sea temperature gradient influenced by global warming. We present long time series of bathypelagic (approximately 1,200-3,600 m) particle fluxes from a coastal (CBeu: 2003-2016) and an offshore (CBmeso: 1988-2016) sediment trap setting located in the Canary Current upwelling. Organic carbon (C org) and biogenic opal (BSi, diatoms) fluxes were twofold to threefold higher at the coastal upwelling site compared to the offshore site, respectively, and showed higher seasonality with flux maxima in spring. A relationship between winter and spring BSi fluxes to the North Atlantic Oscillation index was best expressed at the offshore site CBmeso. Lithogenic (dust) fluxes regularly peaked in winter when frequent low-altitude dust storms and deposition occurred, decreasing offshore by about threefold. We obtained a high temporal match of short-term peaks of BSi and dust fluxes in winter to spring at the inner site CBeu. We found synchronous flux variations at both sites and an anomalous year 2005, characterized by high BSi and C org fluxes under a low North Atlantic Oscillation. C org and BSi fluxes revealed a decreasing trend from 2006 to 2016 at the coastal site CBeu, pointing to coastal upwelling relaxation during the last two decades. The permanent offshore upwelling zone of the deflected Canary Current represented by the flux record of CBmeso showed no signs of increasing upwelling as well which contradicts the Bakun hypothesis.

The Canary Islands region occupies a key position with respect to biogeochemical cycles, with the zonal transition from oligotrophic to nutrient-rich waters and the contribution of Saharan dust to the particle flux. We present the distribution of geochemical proxies (TOC, carbonate, d 15 N, d 13 C org , C/N-ratio) and micropaleontological parameters (diatoms, dinoflagellates, foraminifera, pteropods), in 80 surface-sediment samples in order to characterise the influence of coastally upwelled water on the domain of the subtropical gyre.

Using data collected during the DYBAGA and ECO cruises, remote sensing chlorophyll-a estimations and the averaged upwelling index of the previous fortnight (Iw'), we studied the variability of the sea surface CO2 fugacity (fCO2) over the Galician continental shelf during three seasonal cycles. Sea surface salinity (SSS) distribution controlled fCO2 mainly in spring, while sea surface temperature (SST) did so during periods of intense cooling in November and warming in June. The uptake of carbon by photosynthetic activity, which was more intense during spring and autumn, masked the surface increase in the dissolved inorganic carbon concentration during upwelling events, especially during spring. A significant low correlation between fCO 2 and I w ' was found during spring and summer when upwelling events were observed, whereas no relationship was observed during the downwelling period. High fCO2 exceeding atmospheric values was only found during the summer stratification breakdown. Although sea-air CO2 fluxes showed a marked inter-annual variability, surface waters off the Galician coast were net sinks for atmospheric CO2 in every seasonal cycle, showing a lower CO2 uptake (~65%) compared to previously published values. Marked inter-annual changes in the sea-air CO2 fluxes seem to be influenced by fresh water inputs on the continental shelf under different meteorological scenarios.

The Newport Hydrographic (NH) Line along 44.65° N off central Oregon was sampled seasonally during two epochs: 1961–1971 through the TENOC program and 1997–2003 through the GLOBEC Northeast Pacific Long Term Observations Program (LTOP); some observations are available for 2004 and 2005. During TENOC, the line extended 305km offshore to 128° W, with stations 18km apart over the continental shelf and 36km offshore. During LTOP, the line was shorter (to 126° W) with closer station spacing over the ...

1] The offshore propagation of mesoscale eddies contributes significantly to expanding the area of high chlorophyll concentration beyond the coastal upwelling center as shown by satellite data of chlorophyll, wind stress, sea level anomalies between (1997 -2003) off central Chile. Mesoscale eddies ($6.45 Â 10 3 km 2 ) formed near the coastal zone in spring-summer have mean seaward speeds of $1.68 km d À1 and reach $500 km offshore in winter. Chlorophyll concentrations along eddy paths are elevated by nutrient pumping and by nutrients and/or chlorophyll transported from the coastal zone. Eddies make up >50% of the winter (weak upwelling) chlorophyll peak in the coastal transition zone. Coupling between eddies and upwelling extends central Chile's high productivity area offshore and prolongs it towards winter.

The Southern Brazilian Bight (SBB) is a large semi-enclosed marine ecosystem which stands as one of the most productive coastal regions of Brazil, supporting more than 20% of Brazilian industrial fisheries. Primary production is sustained by the upwelling of the cold and nutrient rich South Atlantic Central Water during the austral summer, provided by a seasonal meteorologically controlled upwelling system, coupled with the frequent development of eddies from Brazil's Current. Many of the exploited fish species spend their planktonic stages confined within the SBB dependencies. The paper brings out some evidences about possible El Niño/La Ninã teleconnections and their possible effects over the oceanographic regime and biological productivity; and therefore, over the living resource dynamics of the studied area. Among these evidences are the modifications detected in the community structure of benthic fishes at an upwelling "hot-spot" (Arraial do Cabo), as well as the fluctuations of the Brazilian sardine catches, which seem to be in phase with intense El Niño events. New evidences are presented through a Hovmoller temperature diagram which shows the presence of cold waters over the SBB's shelf during the 1982/83 El Ninõ/La Niña, contrasting with the less intense 1986/87 phenomenon.

Blue whales Balaenoptera musculus meet the highest prey demands of any predator that has ever existed by feeding exclusively upon dense but patchy schools of pelagic euphausiids. We examined the role that seasonally high primary production supported by coastal upwelling combined with topographic breaks off California play in creating, collecting, and maintaining euphausiids at densities sufficient to allow exploitation by whales. We used concurrent ship-and mooringbased oceanographic, hydroacoustic, and net sampling, whale-sighting records, visual surveys, and time-depth recorder deployment to examine temporal and spatial linkages between (1) intensity of upwelling, (2) primary production, (3) development, density and distribution of euphausiids, and (4) the distribution, abundance, and foraging behavior of blue whales in Monterey Bay, California between 1992 and 1996. Blue whales fed exclusively upon adult euphausiids Thysanoessa spinifera and Euphausia pacifica that were larger than those generally available in the Bay. Foraging whales dove repeatedly to dense euphausiid aggregations between 150 and 200 m on the edge of the Monterey Bay Submarine Canyon. Euphausiid aggregations where whales were foraging averaged 153 g m -3 , approximately 2 orders of magnitude greater than mean euphausiid densities in the Bay (1.3 g m -3 ). High euphausiid densities are supported by high primary production between April and August (249 mg C m -3 d -1 ) and a submarine canyon that provides deep water down-current from an upwelling region. Peak euphausiid densities occur in late summer/early fall, lagging the seasonal increase in primary production by 3 to 4 mo. This lag results from the temporal development of euphausiids spawned around the spring increase in primary production and the shoreward collapse of productivity due to decreased upwelling in late summer. The migratory movements of the California blue whale probably reflect seasonal patterns in productivity in other foraging areas similar to those we describe for Monterey Bay.

Upwelling is a typical phenomenon of the Baltic Sea. Because the Baltic Sea is a semi-enclosed basin, winds from favorable directions blowing predominately parallel to the coast cause upwelling leading to vertical displacement of the water body and mixing. During the thermal stratified period, upwelling can lead to a strong sea-surface temperature drop of more than 10°C changing drastically the thermal balance and stability conditions at the sea-surface. Upwelling can play a key role in replenishing the euphotic zone with the nutritional components necessary for biological productivity when the surface layer is depleted of nutrients. Consequently, it has been found out that in such areas where upwelling lifts phosphorus-rich deep water to the surface, the N/P ratio becomes low which favors the blooming of nitrogen-fixing blue-green algae. The rapid temperature decrease during such events was recognized and documented a long time ago when temperature measurements became available. Thus, the study of the upwelling process has a long tradition. However, although the importance of upwelling has generally been accepted for the Baltic Sea, no general review of upwelling exists. The objective of this paper is a comprehensive review of the upwelling process, its dynamics and reflections to ecosystem processes in the Baltic Sea using all relevant literature which will help to close the gaps of present knowledge and some recommendations for future work are outlined accordingly.

The Northern Humboldt Current Ecosystem is one of the most productive in the world in terms of fish production. Its location near to the equator permits strong upwelling under relatively low winds, thus creating optimal conditions for the development of plankton communities. These communities ultimately support abundant populations of grazing fish such as the Peruvian anchoveta, Engraulis ringens. The ecosystem is also subject to strong inter-annual environmental variability associated with the El Niño Southern Oscillation (ENSO), which has major effects on nutrient structure, primary production, and higher trophic levels. Here our objective is to model the contributions of several external drivers (i.e. reconstructed phytoplankton changes, fish immigration, and fishing rate) and internal control mechanisms (i.e. predator-prey) to ecosystem dynamics over an ENSO cycle. Steady-state models and timeseries data from the Instituto del Mar del Perú (IMARPE) from 1995 to 2004 provide the base data for simulations conducted with the program Ecopath with Ecosim. In simulations all three external drivers contribute to ecosystem dynamics. Changes in phytoplankton quantity and composition (i.e. contribution of diatoms and dino-and silicoflagellates), as affected by upwelling intensity, were important in dynamics of the El Niño of 1997-98 and the subsequent 3 years. The expansion and immigration of mesopelagic fish populations during El Niño was important for dynamics in following years. Fishing rate changes were the most important of the three external drivers tested, helping to explain observed dynamics throughout the modeled period, and particularly during the post-El Niño period. Internal control settings show a mix of predator-prey control settings; however a ''wasp-waist" control of the ecosystem by small pelagic fish is not supported.