Iberian Upwelling Research Articles

Seasonal, Interannual and Long‐Term Variability of Sea Surface Temperature in the NW Iberian Upwelling, 1982–2020

AbstractHere the seasonal, inter‐annual and long‐term variability of satellite‐derived sea surface temperature (SST) was analyzed in the NW Iberian margin from 1982 to 2020 to explore spatial differences at high (5‐km) resolution. In‐situ temperature measurements from five coastal buoys were used to validate the satellite‐derived SST data, discarding pixels from areas close to the shoreline. Regional SST increased significantly from 0.07 to 0.25°C per decade, with the lowest rates in shelf waters directly affected by seasonal coastal upwelling. Upwelling filaments also contributed to dampen the temperature increase in the adjacent slope and ocean waters. The spatial variability observed in the amplitude and timing of the seasonal cycle of SST is directly related to hydrography and circulation patterns of the region such as upwelling events during summer and the development of the river's buoyant plume and the warm Iberian Poleward Current during winter.

Climatic resilience: Marine heatwaves do not influence the variations of green crab (Carcinus maenas) megalopae supply patterns to a Western Iberian estuary

Extreme climatic events like marine heatwaves (MHWs) are becoming more frequent, intense, and longer lasting all around the world. The consequences of these anomalously warm periods are devastating for marine ecosystems. Still, little is known about these extreme events off the western Iberia coast. Here we analyzed MHW events occurring from 1982 to 2020 on the Aveiro coast, western Iberia coast of Portugal. A total of 79 events were detected for the region, with an average duration of 15.8 days, and a mean intensity of 1.9 °C ± 0.4 °C above the 90th percentile of sea surface temperatures (SST) for the region. The maximum intensity of the events has increased by 0.5 °C over the last decade. The relation between SST, and therefore, MHW events, the North Atlantic Oscillation index (NAO), and the regional Iberian Upwelling Index (UI) was identified. The intense upwelling of the region seems to mitigate the duration of warming conditions, resulting in shorter MHW events. Furthermore, the impacts of SST and MHW events on the supply patterns of Carcinus maenas megalopae were examined, utilizing daily data from 2002, 2006–2009, 2012, and 2013, collected at the entrance of Ria de Aveiro. Cross-correlations were employed to assess the effect of SST on megalopae supply, while ordinary least square cumulative sums were used to identify variations over time. The influence of SST on supply was noticed with a 5-to-11-day lag, but this relation changed over the years. Contrary to our hypothesis, we found no evidence supporting a diminishment in megalopae supply due to MHW events. These elusive findings, coupled with the apparent lack of influence of these extreme events, highlight the relatively weak intensity and brief duration of the MHW events in the region, coupled with the high thermal tolerance of these species.

Seasonal ventilation controls nitrous oxide emission in the NW Iberian upwelling

Despite their small spatial extent, coastal upwelling systems are an important source of oceanic nitrous oxide (N2O) to the atmosphere. To date, hot-spot N2O emissions have been reported for low oxygen waters of the eastern boundary upwelling systems at their tropical latitudes, but there is a limited number of studies in their “oxygenated” temperate latitudes. This is the first study of the N2O cycle in the NW Iberian Upwelling system, where we investigated the seasonality of the N2O concentrations and their emissions to the atmosphere, along with the spatial differences in this coastal region in response to the upwelling. Monthly observations were collected from February 2017 to July 2018, in two hydrographic sections within the Ría of Vigo and Ría of A Coruña, two coastal embayments with contrasting response to the upwelling of the Eastern North Atlantic Central Water (ENACW) in the region. N2O concentrations ranged between 8.56 to 12.53 nmol kg−1 (94–121 % of saturation) in the shelf, and from 8.62 to 17.60 nmol kg−1 (94–203 % of saturation) inside the rías, with the highest N2O concentration at the bottom, which increase as the upwelling progress from April to October. The air-sea fluxes of N2O varied between −1.6 to 3.26 µmol m−2 d−1 in the shelf and −1.53 to 7.00 µmol m−2 d−1 inside the rías. Local differences on the ventilation and remineralization pattern drives the seasonality of N2O and differences between Ria of Vigo and Ria of A Coruña, being the higher values of N2O concentrations and air-sea fluxes registered in the inner Ria of Vigo. Our study reports the N2O emissions of an upwelling system in a temperate latitude, where the upwelling waters are central waters relatively well ventilated in terms of oxygen content, behaving as a moderate low net source of N2O to the atmosphere compared to tropical upwelling latitudes, characterised by a lower oxygen content.

Rapid tropicalization evidence of subtidal seaweed assemblages along a coastal transitional zone

Anthropogenic climate change, particularly seawater warming, is expected to drive quick shifts in marine species distribution transforming coastal communities. These shifts in distribution will be particularly noticeable in biogeographical transition zones. The continental Portuguese coast stretches from north to south along 900 km. Despite this short spatial scale, the strong physical gradient intensified by the Iberian upwelling creates a transition zone where seaweed species from boreal and Lusitanian-Mediterranean origin coexist. On the northern coast, kelp marine forests thrive in the cold, nutrient-rich oceanic waters. In the south, communities resemble Mediterranean-type seaweed assemblages and are dominated by turfs. Recent evidence suggests that in these coastal areas, marine intertidal species are shifting their distribution edges as a result of rising seawater temperatures. Taking advantage of previous abundance data collected in 2012 from subtidal seaweed communities, a new sampling program was carried out in the same regions in 2018 to assess recent changes. The results confirmed the latitudinal gradient in macroalgal assemblages. More importantly we found significant structural and functional changes in a short period of six years, with regional increases of abundance of warm-affinity species, small seaweeds like turfs. Species richness, diversity, and biomass increase, all accompanied by an increase of community temperature index (CTI). Our findings suggest that subtidal seaweed communities in this transitional area have undergone major changes within a few years. Evidence of “fast tropicalization” of the subtidal communities of the Portuguese coast are strong indication of the effects of anthropic climate change over coastal assemblages.

CO2 budget of cultured mussels metabolism in the highly productive Northwest Iberian upwelling system

Assessing the carbon footprint of marine bivalve aquaculture demands an accurate estimation of the CO2 release associated to capital goods and aquaculture operations but also to the metabolic CO2 budget of the cultured species. Nowadays, there are discrepancies on the processes to include in that budget, how to estimate them, and which scale should be applied, from individual to ecosystem. Site-specific environmental conditions and culture methods also affect significantly the estimates. Here, we have gathered environmental, biochemical and metabolic data from published scientific articles, reports and existing databases to present the metabolic CO2 budget for mussel aquaculture in the coastal inlets of the Northwest Iberian upwelling. We analyse the contribution of mussel flesh and shell production jointly and separately. At the individual scale, the shell CO2 budget is estimated from CO2 removal by shell matrix protein synthesis and CO2 release during calcification and respiration to support shell maintenance. Organic carbon in mussel flesh and CO2 released by respiration to support flesh maintenance contribute to the flesh CO2 budget. Only calcification and respiration processes are considered when estimating the metabolic carbon footprint of individual mussels because organic carbon in mussel flesh and shell returns to the atmosphere as CO2 in a relatively short period. While the metabolic carbon footprint associated to mussel shell remains constant at 365 kg CO2 per ton of shell, it varies from 92 to 578 kg CO2 per ton of mussel flesh. This large variability depends on mussel seeding time and harvesting size, due to the differential seasonal growth patterns of flesh and shell. Inclusion of the CO2 potentially immobilised in mussel faeces buried in the sediments would lead to a reduction of the metabolic carbon footprint estimates by up to 6 % compared with the individual estimates.

Dinoflagellate Assemblages in the West Iberian Upwelling Region (Sagres, Portugal) During 1994–2001

Changes in the composition of dinoflagellates from 1994 to 2001 at a station influenced by wind-induced seasonal upwelling off SW Portugal were analyzed in relation to oceanography. 194 taxa of dinoflagellates were detected, the most frequent belonged to the genera Tripos, Protoperidinium, Dinophysis, Diplopsalopsis, Prorocentrum and Lingulodinium. The composition of dinoflagellate communities followed a seasonal pattern, in association with oceanographic forcing and change of upwelling conditions. Harmful species such as Dinophysis acuminata, D. acuta, D. caudata, Gonyaulax spp. and Lingulodinium polyedra were found to develop during the upwelling season, typically comprising summer and early autumn in the West Iberian upwelling system, and also occasionally in the conditions following upwelling events in other seasons.

Larval Fish Community in the Northwestern Iberian Upwelling System during the Summer Period

The Galician shelf (northwestern Iberian Peninsula) is a highly dynamic area with an important multi-species fisheries industry that exploits resources from several habitats, characterized by being not only highly diverse, rich, and productive but also seasonally and interannually variable. Early life stages of different species are distributed throughout the year, with fluctuating abundances and community composition. Likewise, the influence of environmental factors and processes on larval production and survival remains unknown. Sampling was carried out in July 2012, and all the larvae obtained were identified to establish the specific composition of the community in a summer upwelling scenario. The results show no zonation in the species distribution, a consequence of the mixing effects of the upwelling and eddies, with high diversity but low abundance, which render in a slight predominance of a few species. Due to the dependence of planktonic populations on upwelling events, which was not highly pronounced in 2012, we cannot conclude that this was a typical conformation of the Galician summer larval fish community, but it is a first approach to comprehend the community composition.

Phytoplankton communities in two wide-open bays in the Iberian upwelling system

The main meteorological and oceanographic drivers shaping phytoplankton community structure and dynamics are investigated in two wide-open bays influenced by coastal upwelling. Local processes influencing the proliferation of harmful algal bloom species were also investigated. The work was developed during one year in Lisbon Bay (central-west coast) and in Lagos Bay (south coast), both located on the upwelling shadow of prominent headlands. In both bays, the results indicated a bi-modal annual pattern in phytoplankton biomass, and phytoplankton concentration maxima, between spring and late-summer, were associated with high diatom abundances. In Lagos Bay, higher dinoflagellate abundances were observed from spring to autumn, while in Lisbon Bay these were recorded from late-summer to autumn. The coccolithophores were a frequent group all year round in Lisbon Bay, which contrasts with Lagos Bay where they were the least frequent group. The phytoplankton community structure showed significant spatial and seasonal differences. The community succession pattern indicated the existence of four biological seasons in Lisbon Bay and at the offshore site in Lagos Bay. By contrast, the nearshore site in Lagos Bay was characterized by having no significant differences between summer and autumn. Differences in HAB species/groups were also observed between the bays. In general, HABs occurred at higher concentrations and were more persistent in Lagos Bay.In both bays, winter assemblages were influenced by water column mixing processes, although precipitation was also relevant in Lagos. Upwelling was a key driver of the spring phytoplankton community in Lagos Bay, while in Lisbon Bay other factors seemed to drive the spring phytoplankton assemblages. Both summer and autumn communities were related to thermal stratification. In autumn, the occurrence of reversal circulation patterns also played an important role in shaping the phytoplankton communities, especially in Lagos Bay. Overall, this study revealed differences on phytoplankton community patterns in two wide-open bays, shaped by the local environmental variables.

ARIOS: a database for ocean acidification assessment in the Iberian upwelling system (1976–2018)

Abstract. A data product of 17 653 discrete samples from 3343 oceanographic stations combining measurements of pH, alkalinity and other biogeochemical parameters off the northwestern Iberian Peninsula from June 1976 to September 2018 is presented in this study. The oceanography cruises funded by 24 projects were primarily carried out in the Ría de Vigo coastal inlet but also in an area ranging from the Bay of Biscay to the Portuguese coast. The robust seasonal cycles and long-term trends were only calculated along a longitudinal section, gathering data from the coastal and oceanic zone of the Iberian upwelling system. The pH in the surface waters of these separated regions, which were highly variable due to intense photosynthesis and the remineralization of organic matter, showed an interannual acidification ranging from −0.0012 to −0.0039 yr−1 that grew towards the coastline. This result is obtained despite the buffering capacity increasing in the coastal waters further inland as shown by the increase in alkalinity by 1.1±0.7 and 2.6±1.0 µmol kg−1 yr−1 in the inner and outer Ría de Vigo respectively, driven by interannual changes in the surface salinity of 0.0193±0.0056 and 0.0426±0.016 psu yr−1 respectively. The loss of the vertical salinity gradient in the long-term trend in the inner ria was consistent with other significant biogeochemical changes such as a lower oxygen concentration and fertilization of the surface waters. These findings seem to be related to a growing footprint of sediment remineralization of organic matter in the surface layer of a more homogeneous water column. Data are available at https://doi.org/10.20350/digitalCSIC/12498 (Pérez et al., 2020).

About Pigmented Nanoflagellates and the Importance of Mixotrophy in a Coastal Upwelling System

Mixotrophy, understood as food ingestion and photosynthesis occurring in the same organism, is a nutrition mode relatively common in marine protists. Among these, pigmented nanoflagellates 2-20 µm in size (PNF) are now known to be responsible for a significant part of consumption of bacteria in the open ocean. However, knowledge about the importance of the mixotrophic nutrition of these organisms in coastal upwelling systems, where autotrophy prevails, is very limited. Here we compile the limited available information about mixotrophy of PNF in coastal upwelling systems, focusing on the NW Iberian upwelling, to show that this type of nutrition is relevant in these productive systems and to urge for further studies. Several indirect approaches allow inferring that mixotrophy was significant for PNF in the NW Iberian upwelling, with heterotrophy supplying seventy-five percent of the total carbon requirements in this plankton group. This new insight has major implications for our view of marine food webs in coastal upwelling regions, and must be taken into account in the construction of more accurate biogeochemical models of the transfer of matter and energy in these marine areas.

Unexpected nutrient influence on the thermal ecophysiology of seaweeds that recently followed opposite abundance shifts

World's oceans are warming, and recent studies suggest that the Iberian upwelling system may be weakening. To understand the potential consequences of both trends, six intertidal seaweeds that recently followed opposite upward and downward abundance shifts in the Iberian upwelling region were exposed for six weeks to conditions simulating present and warmed scenarios, combined with nutrient treatments emulating the influence and absence of the upwelling. Unlike expectations, a high nutrient supply did not ameliorate the effects of warming. Instead, warming slowed down growth in four seaweeds and accelerated the photosynthesis of downward seaweeds only if nutrients were abundant. In a weakened upwelling scenario, nutrient limitation might more strongly influence the performance of both upward and downward seaweeds than warming. With a normally functioning upwelling, warming might be more detrimental to the performance of some downward seaweeds as they might would lose their ability to benefit from the extra nutrient input.

An overview of small-scale fisheries in the Northern Portuguese coast

An overview of small-scale fisheries in the Northern Portuguese coast

Sea-Air CO2 Exchange in the SW Iberian Upwelling System during Two Contrasting Climate Cycles: 860–780 ka and 630–520 ka

Analysis of planktonic and benthic foraminifers’ accumulation rates from the Iberian margin reveal a substantial change in the biogenic ocean-atmosphere CO2 exchange during the Mid-Pleistocene Transition (MPT; ~800–650 ka from present). Such changes resulted from the major reorganisations in both surface and deep-water circulation that occurred in the North Atlantic at the time, and affected the behaviour of this upwelling region as a CO2 uptake/release area during climate cycles before and after the MPT. During Marine Isotope Stages (MIS) 21-MIS 20 (860–780 ka), this margin acted mostly as an uptake area during interglacials and early glacials. During glacial maxima and terminations it would be neutral because, although surface production and export were very low, carbon storage occurred at the seafloor. During MIS 15-MIS 14 (630–520 ka), the pattern was the opposite, and the Iberian margin worked as a neutral, or as a source area during most interglacials, while during glacials it acted as an important uptake area. Present findings support the idea that glacial/interglacial atmospheric pCO2 oscillations are partly driven by alterations in the meridional overturning circulation that results in substantial variations of the biological pump, and carbon sequestration rate, in some high-productivity regions.

Sardine (Sardina pilchardus) larval dispersal in the Iberian upwelling system, using coupled biophysical techniques

The European sardine (Sardina pilchardus) is the most important small pelagic fishery of the Western Iberia Upwelling Ecosystem (WIUE). Recently, recruitment of this species has declined due to changing environmental conditions. Furthermore, controversies exist regarding its population structure with barriers thought to exist between the Atlantic-Iberian Peninsula, Northern Africa, and the Mediterranean. Few studies have investigated the transport and dispersal of sardine eggs and larvae off Iberia and the subsequent impact on larval recruitment variability. Here, we examine these issues using a Regional Ocean Modeling System climatology (1989–2008) coupled to the Lagrangian transport model, Ichthyop. Using biological parameters from the literature, we conduct simulations that investigate the effects of spawning patchiness, diel vertical migration behaviors, and egg buoyancy on the transport and recruitment of virtual sardine ichthyoplankton on the continental shelf. We find that release area, release depth, and month of release all significantly affect recruitment. Patchiness has no effect and diel vertical migration causes slightly lower recruitment. Egg buoyancy effects are significant and act similarly to depth of release. As with other studies, we find that recruitment peaks vary by latitude, explained here by the seasonal variability of offshore transport. We find weak, continuous alongshore transport between release areas, though a large proportion of simulated ichthyoplankton transport north to the Cantabrian coast (up to 27%). We also show low level transport into Morocco (up to 1%) and the Mediterranean (up to 8%). The high proportion of local retention and low but consistent alongshore transport supports the idea of a series of metapopulations along this coast.

Atmosphere-ocean feedbacks in a coastal upwelling system

The COAWST (Coupled Ocean-Atmosphere-Wave-Sediment Transport) modelling system is used in different configurations to simulate the Iberian upwelling during the 2012 summer, aiming to assess the atmosphere-ocean feedbacks in the upwelling dynamics. When model results are compared with satellite measurements and in-situ data, two-way coupling is found to have a moderate impact in data-model statistics. A significant reinforcement of atmosphere-ocean coupling coefficients is, however, observed in the two-way coupled run, and in the WRF and ROMS runs forced by previously simulated SST and wind fields, respectively. The increasing in the coupling coefficient is associated with slight, but potentially important changes in the low-level coastal jet in the atmospheric marine boundary layer. While these results do not imply the need for fully coupled simulations in many applications, they show that in seasonal numerical studies such simulations do not degrade the overall model performance, and contribute to produce better dynamical fields.

Characterization of the structure and cross‐shore transport properties of a coastal upwelling filament using three‐dimensional finite‐size Lyapunov exponents

AbstractThe three‐dimensional structure, dynamics, and dispersion characteristics of a simulated upwelling filament in the Iberian upwelling system are analyzed using Lagrangian tools. We used a realistic regional simulation of the western Iberian shelf which is concomitant with an in situ oceanographic campaign that surveyed the area. We compute 3‐D fields of finite‐size Lyapunov exponents (FSLE) from 3‐D velocity fields and extract the field's ridges to study the spatial distribution and temporal evolution of the Lagrangian Coherent Structures (LCSs) evolving around the filament. We find that the most intense curtain‐like LCSs delimit the boundaries of the whole filamentary structure whose general properties match well the observations. The filament interior is characterized by small dispersion of fluid elements. Furthermore, we identify a weak LCS separating the filament into a warmer vein and a colder filament associated with the interaction of a mesoscale eddy with the upwelling front. The cold upwelled water parcels move along the filament conserving their density. The filament itself is characterized by small dispersion of fluid elements in its interior. The comparison of LCSs with potential temperature and salinity gradient fields shows that the outer limits of the filament coincide with regions of large hydrographic gradients, similar to those observed, explaining the isolation of the interior of the filament with the surrounding waters. We conclude that the Lagrangian analysis used in this work is useful in explaining the dynamics of cross‐shore exchanges of materials between coastal regions and the open ocean due to mesoscale processes.

Feeding Relationship between Octopus vulgaris (Cuvier, 1797) Early Life-Cycle Stages and Their Prey in the Western Iberian Upwelling System: Correlation of Reciprocal Lipid and Fatty Acid Contents.

Under the influence of the Western Iberian upwelling system, the Iberian Atlantic coast holds important hatcheries and recruitment areas for Octopus vulgaris. Recently identified as an octopus hatchery, the Ría de Vigo harbors an important mesozooplankton community that supports O. vulgaris paralarvae during the first days of their planktonic stage. This study represents a preliminary approach to determine the nutritional link between wild O. vulgaris hatchlings, paralarvae and their zooplankton prey in the Ría de Vigo, by analyzing their lipid class content and fatty acid profiles. The results show that octopus hatchlings are richer in structural lipids as phospholipids and cholesterol, while the zooplankton is richer in reserve lipids like triacylglycerol and waxes. Zooplankton samples are also particularly rich in C18:1n9 and 22:6n3 (DHA), that seem to be successfully incorporated by O. vulgaris paralarvae thus resulting in a distinct fatty acid profile to that of the hatchlings. On the other hand, content in C20:4n6 (ARA) is maintained high through development, even though the zooplankton is apparently poorer in this essential fatty acid, confirming its importance for the development of O. vulgaris paralarvae. The content in monounsaturated fatty acids, particularly C18:1n7, and the DHA: EPA ratio are suggested as trophic markers of the diet of O. vulgaris paralarvae.

Rapid response to coastal upwelling in a semienclosed bay

AbstractBays/estuaries forced by local wind show bidirectional exchange flow. When forced by remote wind, they exhibit unidirectional flow adjustment to coastal sea level. Acoustic Doppler Current Profiler observations over 1 year show that the Ria de Vigo (Iberian Upwelling) responds to coastal wind events with bidirectional exchange flow. The duration of the upwelling and downwelling events, estimated from the current variability, was ~3.3 days and ~2.6 days, respectively. Vectorial correlations reveal a rapid response to upwelling/downwelling, in which currents lag local wind by <6 h and remote wind by <14 h, less than the Ekman spinup (17.8 h). This rapidity arises from the ria's narrowness (nonrotational local response), equatorward orientation (additive remote and local wind responses), depth greater than the Ekman depth (penetration of shelf circulation into the interior), and vertical stratification (shear reinforcing shelf circulation). Similar rapid responses are expected in other narrow bays where local and remote winds act together and stratification enhances bidirectional flow.

Life strategies of cephalopod paralarvae in a coastal upwelling system (NW Iberian Peninsula): insights from zooplankton community and spatio‐temporal analyses

AbstractThe early life stages of cephalopods ‐ octopods, squids, sepiolids and ommastrephids ‐, are uncommon in zooplankton samples and little is known about their life strategies. Accordingly, cephalopod paralarvae were examined in the upwelling ecosystem of the Ría de Vigo (NW Spain) at night from 2008 to 2010. Multivariate analyses and generalized linear models (GLMs) were used to explore relationships between cephalopod paralarvae and the zooplankton communities that they inhabited in 2008. In addition, the foraging strategy and prey preferences of Octopus vulgaris paralarvae within these communities were determined. Multivariate and GLM results showed a strong association of cephalopod paralarvae with coastal and frontal zooplankton communities. Octopus paralarvae were shown to be specialist predators with a strong preference for decapod zoeae in each of the communities examined. Using the three years of sampling, GLM analyses of paralarval spatio‐temporal variations in relation with the upwelling strength showed a positive relationship with upwelling intensity for O. vulgaris and sepiolids, as well as contrasting temporal, horizontal and vertical distributions for the different paralarvae analysed. Under strong upwelling events, Octopus paralarvae were more abundant in surface waters, whereas the abundance of loliginids and sepiolids was higher in the water column. This vertical behaviour in conjunction with the physical conditions of the Western Iberian Upwelling ecosystem suggests the coexistence of two different life strategies: a coastal strategy displayed by loliginid and sepiolid paralarvae that are retained over the shelf, and an oceanic strategy displayed by O. vulgaris paralarvae that are dispersed far from the shelf.

Environmental change in the Western Iberia Upwelling Ecosystem since the preindustrial period revealed by dinoflagellate cyst records

We present the first multi-site study of dinoflagellate cyst records spanning ca. AD 1860–2000 from the west Iberian coast. Our aim was to reconstruct environmental changes in the Western Iberia Upwelling Ecosystem, one of the most biologically productive areas in the world, and an active fishery region. A major shift in cyst assemblages was recorded off the northwestern shelf sector between 1920 and 1950 towards autotrophic dominance, and consisted of a multi-fold increase in total cyst concentrations and cysts of Lingulodinium polyedrum, accompanied by an increase in Protoceratium reticulatum cysts. The observed changes pre-date the industrialization of agriculture in Portugal, and are concomitant with a shift in the North Atlantic Oscillation (NAO) towards negative indices (higher river input) and increasing sea-surface temperatures. The southernmost record, with reduced river- and human influence, showed only minor changes during the 20th century. Here, an increase in Protoperidinioid cysts after the 1980s is related to upwelling intensification. Our study indicates that the main changes recorded in the Western Iberian Upwelling system during the 20th century were driven by regional climate variability (warming, increased water stability and nutrient availability), possibly enhanced by anthropogenic nutrient input from the second half of the century. Our results highlight the complexity of the environmental drivers that may act upon dinoflagellate communities within the same region. The 20th-century environmental change in the Western Iberian Ecosystem has resulted in a shift towards marked autotrophic dominance of dinoflagellate cyst communities, and the northward expansion of species associated with Harmful Algal Blooms.