Afonso Ferreira

University of Lisbon | UL · MARE-Marine and Environmental Sciences Centre

The Northern Antarctic Peninsula (NAP), located in West Antarctica, is amongst the most impacted regions worldwide by recent warming events. Its vulnerability to climate change has already led to an accumulation of severe changes along its ecosystems. This work reviews the current findings on impacts observed in phytoplankton communities occurring...

The Atlantic Meridional Transect (AMT) program (www.amt-uk.org) provides the perfect opportunity to observe the phytoplankton community size structure over a long latitudinal transect 50 o N to 50 o S, thereby covering the most important latitude-related basin-scale environmental gradients of the Atlantic Ocean. This work presents cell abundance da...

The Northern Antarctic Peninsula (NAP) shows shifts in phytoplankton distribution and composition along its warming marine ecosystems. However, despite recent efforts to mechanistically understand these changes, little focus has been given to the phytoplankton seasonal succession, remaining uncertainties regarding to distribution patterns of emergi...

The Western Iberian Coast (WIC) is characterized by a dynamic coastal upwelling system with interactions between oceanographic features and continental river run‐off. The present study investigates the spatio‐temporal variability in the concentrations of Chlorophyll a (Chl a ) and turbidity, and their relationships with physical and other biogeoche...

Changes in coccolithophore productivity in response to climate-driven ocean warming are likely to have cascading biogeochemical effects that feed back to the changing climate. This paper investigates the role (and interplay) of large- scale oceanographic and atmospheric processes across the North- and Equatorial Atlantic, including Saharan dust dep...

The European sardine (Sardina pilchardus) is the most abundant and socio-economically important small pelagic fish species in Western Iberia Upwelling Ecosystem. As a result of a long series of low recruitments, sardine biomass off Western Iberia has greatly reduced since the 2000s. Recruitment of small pelagic fish is mainly dependent on environme...

Portugal’s vast coast has great socioeconomic potential, characterized by high hydrodynamic and geomorphologic diversity. The growth of phytoplankton, the base of the marine food chain, is shaped by environmental characteristics. The goal was to evaluate the main drivers of phytoplankton dynamics and identify coastal areas with high biomass. Four s...

The western Antarctic Peninsula (WAP) is a climatically sensitive region where foundational changes at the basis of the food web have been recorded; cryptophytes are gradually outgrowing diatoms together with a decreased size spectrum of the phytoplankton community. Based on a 11-year (2008-2018) in-situ dataset, we demonstrate a strong coupling be...

A global in situ data set for validation of ocean colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data s...

The Atlantic sector of the Southern Ocean has been rapidly changing over the last century. Many of those changes are driven by climate anomalies such as the El Niño Southern Oscillation and the Southern Annular Mode, which affect biological processes that scale up the food web. In this paper, we use δ13C and δ15N time-series of dentine growth layer...

A global in-situ data set for validation of ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI) is presented. This version of the compilation, starting in 1997, now extends to 2021, which is important for the validation of the most recent satellite optical sensors such as Sentinel 3B OLCI and NOAA-20 VIIRS. The data s...

Chlorophyll-a (Chl-a) underestimation by global satellite algorithms in the Southern Ocean has long been reported, reducing their accuracy, and limiting the potential for evaluating phytoplankton biomass. As a result, several regional Chl-a algorithms have been proposed. The present work aims at assessing the performance of both global and regional...

Salinity is one of the oldest parameters being measured in oceanography and one of the most important to study in the context of climate change. However, its quantification by satellite remote sensing has been a relatively recent achievement. Currently, after over ten years of data gathering, there are still many challenges in quantifying salinity...

Phytoplankton biomass, through its proxy, Chlorophyll a , has been assessed at synoptic temporal and spatial scales with satellite remote sensing (RS) for over two decades. Also, RS algorithms to monitor relative size classes abundance are widely used; however, differentiating functional types from RS, as well as the assessment of phytoplankton str...

Diatoms play crucial functions in trophic structure and biogeochemical cycles. Due to poleward warming, there has been a substantial decrease in diatom biomass, especially in Antarctic regions that experience strong physical changes. Here we analyze the phyto-plankton contents of water samples collected in the spring/summer of 2015/2016 off the Nor...

While primary productivity is more stable in oceanic regions, it may vary to a great extent with the proximity to coasts, where mesoscale processes may intertwine and shape phytoplankton community composition and biomass. Sometimes, this may lead to the development of anomalous phytoplankton blooms (i.e., episodic blooms that exceed several times t...

Phytoplankton bloom phenology studies are fundamental for the understanding of marine ecosystems. Mismatches between fish spawning and plankton peak biomass will become more frequent with climate change, highlighting the need for thorough phenology studies in coastal areas. This study was the first to assess phytoplankton bloom phenology in the Wes...

The phytoplankton comprises different shapes and sizes, having different impacts on the biogeochemical cycles. The development of models for Phytoplankton Size Classes ( is based mainly on the empirical relationship between marker pigments and chlorophyll a The present study sought to investigate the PSC's spatial variability along the Portuguese c...

Marine coastal areas have high social-economic relevance and ensuring the good quality of these areas has gained importance in the past decades due to the increase of anthropogenic pressures. Understanding the dynamics of these areas is crucial to support management decisions. In this context, phytoplankton communities are generally used as key ind...

Nutrient enrichment in coastal areas can lead to severe disturbances in marine ecosystems with implications on ecosystem functioning. The primary goal of this study was to understand the response of phytoplankton, from a region with intense upwelling events, to pulsed nutrient enrichments. A microcosm experiment using natural assemblages was conduc...

Phytoplankton are the main primary producers in marine ecosystems, supporting important food webs. They are recognized as important indicators of environmental changes in oceans and coastal waters. Ocean color remote sensing has been extensively used to study phytoplankton (i.e., chlorophyll a – CHL – as a proxy of phytoplankton biomass) throughout...

Phytoplankton is widely recognized as an essential bioindicator of environmental changes in marine ecosystems, stemming from their role as the main marine primary producers and their susceptibility to rapid changes in their environment. Throughout the last few decades, ocean color remote sensing (OCRS) has emerged as a mandatory tool to study phyto...

In the last few decades, several studies have reported substantial effects on coastal ecosystems driven by anthropogenic pressure, e.g. climate change (Fulweiler & Nixon, 2009), eutrophication (Cerco & Noel, 2013), fisheries (Gascuel et al., 2016), etc. Such threats are ever-changing and can disturb and alter phytoplankton communities at several ta...