Esther Garcés

• Ph.D.
• Spanish National Research Council at Institut de Ciències del Mar

Marine macroalgae surfaces create a nutrient‐rich environment that promotes the formation of epiphyte biofilms. Biofilms are complex systems that facilitate ecological interactions within the community, yet parasitism remains largely unexplored. This study describes the diversity and temporal dynamics of the microeukaryotic community in the biofilm...

Marine microbial communities differ genetically, metabolically, and ecologically according to their lifestyle, and they may respond differently to environmental changes. In this study, we investigated the seasonal dynamics of bacterial assemblies in the free‐living (FL) and particle‐associated (PA) fractions across a span of 6 years in the Blanes B...

Marine harmful algal blooms (HABs), caused by various aquatic microalgae, pose significant risks to ecosystems, some socio-economic activities and human health. Traditionally managed as a public health issue through reactive control measures such as beach closures, seafood trade bans or closure of mollusc production areas, the multifaceted linkages...

Parasitism is the most common lifestyle on Earth and has emerged many times independently across the eukaryotic tree of life. It is frequently found among chytrids (Chytridiomycota), which are early-branching unicellular fungi that feed osmotrophically via rhizoids as saprotrophs or parasites. Chytrids are abundant in most aquatic and terrestrial e...

Extracellular Vesicles (EVs) are likely an important strategy of transport and communication in marine microbial community. Their isolation and characterization from axenic culture of microbial eukaryotes represents a technological challenge not fully solved. Here, for the first time, we isolated EVs from a near-axenic culture of the toxic dinoflag...

Background Ocean microbes constitute ~ 70% of the marine biomass, are responsible for ~ 50% of the Earth’s primary production and are crucial for global biogeochemical cycles. Marine microbiotas include core taxa that are usually key for ecosystem function. Despite their importance, core marine microbes are relatively unknown, which reflects the la...

A new chytrid genus and species was isolated and cultured from samples obtained in the Baltic Sea during a dinoflagellate bloom event. This species is characterized by having a spherical sporangium without papillae and zoospores of 2–3 µm in diameter that are released through 3 discharge pores. Molecular phylogeny based on ribosomal operon showed i...

The presence of phytoplankton parasites along the water column was explored at the Long‐Term Ecological Station MareChiara (LTER‐MC) in the Gulf of Naples (Mediterranean Sea) in October 2019. Microscopy analyses showed diatoms dominating the phytoplankton community in the upper layers (0–20 m). Metabarcoding data from the water column showed the pr...

Zoosporic parasites (i.e. fungi and fungi-like aquatic microorganisms) constitute important drivers of natural populations, causing severe host mortality. Economic impacts of parasitic diseases are notable in the microalgae biotech industry, affecting production of food ingredients, biofuels, pharma- and nutraceuticals. While scientific research on...

The interactions of parasitic fungi with their phytoplankton hosts in the marine environment is mostly unknown. In this study, we evaluated the diversity of Chytridiomycota in phytoplankton communities dominated by dinoflagellates at several coastal locations in the NW Mediterranean Sea and demonstrated the most prominent interactions of these para...

El compromís de l’ICM per la igualtat es va fer singularment palès amb l’aprovació al juny del 2021 del I Pla d’Igualtat de Gènere al centre. Aquesta Guia de comunicació inclusiva i no sexista és un dels resultats de l'aplicació de les mesures previstes en l’esmentat Pla. La Guia pretèn ser un instrument que contribueixi a l’ús de termes i expressi...

The last century has witnessed an increasing rate of new disease emergence across the world leading to permanent loss of biodiversity. Perkinsea is a microeukaryotic parasitic phylum composed of four main lineages of parasitic protists with broad host ranges. Some of them represent major ecological and economical threats because of their geographic...

Despite the drive towards equality between women and men in research institutions in recent years and the progress that has been made, there is still a long road ahead. Science is still associated with the male image, and women’s work and contributions are often invisible. Like many other spheres of society, research institutions contribute to the...

This paper presents major gaps and challenges for implementing the UN Decade of Ocean Science for Sustainable Development (2021-2030) in the Mediterranean region. The authors make recommendations on the scientific knowledge needs and codesign actions identified during two consultations, part of the Decade preparatory-phase, framing them in the Medi...

The majority of species of the highly diverse genus Chaetoceros are described as chain-forming, although several species are described as strictly solitary (such as C. tenuissimus) or having an alternate solitary and a chain-forming phase during their life history (such as C. salsugineus). In this study, the diversity of small forms of Chaetoceros...

Recommendations to frame problems and solutions for the pelagic habitats’ assessment

Perkinsea is a phylogenetic group of protists that includes parasites of distantly related hosts. However, its diversity is still mainly composed of environmental sequences, mostly obtained from freshwater environments. Efforts to isolate and culture parasitoids of dinoflagellates have led to the description of several phylogenetically closely rela...

A marine hazard is a potentially damaging event, phenomenon or activity in the marine environment that may cause loss of human life, social and economic disruption or environmental degradation. In the last 30 years, natural and human-induced hazards have caused over 1.6 million victims and the economic losses average 300 thousand million dollars pe...

Bacteria display dynamic abundance fluctuations over time in marine environments, where they play key biogeochemical roles. Here, we characterized the seasonal dynamics of marine bacteria in a coastal oligotrophic time series station, tested how similar the temporal niche of closely related taxa is, and what are the environmental parameters modulat...

The poster explains the experience of the Institut de Ciències del Mar (ICM-CSIC) in the European project Responsible Research in Biosciences (ResBios). The project ResBios is aimed to put Responsible Research and Innovation (RRI) in practice in four institutions, the ICM-CSIC is one of them and is working mainly on 3 RRI aspects: scientific educat...

Many dinoflagellate groups have been overlooked because of their small size compared with their larger counterparts; consequently, little is known about their diversity, distribution, and contribution to the planktonic community. Ansanella is a recently described genus of small marine planktonic dinoflagellates belonging to the order Suessiales. In...

Background: Ocean microbes constitute ~70% of the marine biomass, are responsible for ~50% of the Earth's primary production, and are crucial for global biogeochemical cycles. Marine microbiotas include core taxa that are usually key for ecosystem function. Despite their importance, core marine microbes are relatively unknown, which reflects the la...

Parasites in aquatic systems are highly diverse and ubiquitous. In marine environments, parasite‐host interactions contribute substantially to shaping microbial communities, but their nature and complexity remain poorly understood. In this study, we examined the relationship between Perkinsea parasitoids and bloom‐forming dinoflagellate species. Ou...

Parasites in aquatic systems are highly diverse and ubiquitous. In marine environments, parasite-host interactions contribute substantially to shaping microbial communities, but their nature and complexity remain poorly understood. In this study, we examined the relationship between Perkinsea parasitoids and bloom-forming dinoflagellate species. Ou...

Many fungi have been identified as pathogens of marine algae. Among them, Chytridiomycota have been revealed as relatively highly abundant, but much of the diversity known within these groups is almost entirely based on environmental sequencing data. Here, we present a novel chytridiomycete genus and species, characterized by light microscopical ob...

Bacteria are highly dynamic in marine environments, where they play key biogeochemical roles. Here, we tested how similar the niche of closely related marine bacteria is and what are the environmental parameters modulating their ecological responses in a coastal oligotrophic time series. We further explored how conserved the niche is at broader tax...

Perkinsea are a group of intracellular protist parasites that inhabit all types of aquatic environments and cause significant population declines of a wide variety of hosts. However, the diversity of this lineage is mostly represented by environmental rDNA sequences. Complete descriptions of Perkinsea that infect marine dinoflagellates have increas...

High-throughput sequencing of microbial assemblages has been proposed as an alternative methodology to the traditional ones used in marine monitoring and environmental assessment. Here, we evaluated pico- and nanoplankton diversity as ecological indicators in NW Mediterranean coastal waters by comparing their diversity in samples subjected to varyi...

El presente documento recoge las principales conclusiones extraídas a partir de la encuesta del “Impacto del confinamiento”, elaborada desde el Grupo de 1 Trabajo de Igualdad del ICM, durante el periodo en que la población se encontraba en Estado de Alarma debido a la crisis sanitaria provocada por la pandemia del COVID-19, concretamente del 15 al...

El presente documento recoge las principales conclusiones extraídas a partir de la encuesta del “Impacto del confinamiento”, elaborada desde el Grupo de 1 Trabajo de Igualdad del ICM, durante el periodo en que la población se encontraba en Estado de Alarma debido a la crisis sanitaria provocada por la pandemia del COVID-19, concretamente del 15 al...

A recently published study analyzed the phylogenetic relationship between the genera Centrodinium and Alexandrium, confirming an earlier publication showing the genus Alexandrium as paraphyletic. This most recent manuscript retained the genus Alexandrium, introduced a new genus Episemicolon, resurrected two genera, Gessnerium and Protogonyaulax, an...

A recently published study analyzed the phylogenetic relationship between the genera Centrodinium and Alexandrium, confirming an earlier publication showing the genus Alexandrium as paraphyletic. This most recent manuscript retained the genus Alexandrium, introduced a new genus Episemicolon, resurrected two genera, Gessnerium and Protogonyaulax, an...

Human activities on land result in the high-level production of nutrients. When these nutrients reach coastal waters, they could drive the eutrophication process. Here we present the Land Uses Simplified Index (LUSI), an easy-to-use tool for assessing continental pressures on coastal waters. This assessment is done by indirectly estimating continen...

Changes in phytoplankton composition reveal relevant information about the re- sponse of aquatic systems to environmental drivers. Here, we propose the combined use of particle size measurements and pigment signatures to analyze the changes in the composition of phyto- plankton communities at a coastal location. Canonical correlation analysis (CCA)...

During summer, when oligotrophic conditions prevail offshore in the Mediterranean Sea, enhanced phytoplankton stripes are often observed in nearshore waters. In this study, we examine the cross-shore hydrographic variability and the associated microbial plankton communities in this zone. Detailed cross-shore underway sampling at 47 coastal sites sp...

Determining predictability in community turnover is a key ecological question. In the microbial world, seasonality has been reported for communities inhabiting temperate zones, but not much is known on seasonality for individual species. Specifically, we have a vague understanding on the amount of species displaying predictability during temporal c...

Dinoflagellate blooms are natural phenomena that often occur in coastal areas, which in addition to their large number of nutrient-rich sites are characterized by highly restricted hydrodynamics within bays, marinas, enclosed beaches, and harbors. In these areas, massive proliferations of dinoflagellates have harmful effects on humans and the ecosy...

Parasites are one of the ecologically most relevant groups of marine food webs, but their taxonomic and biological complexity hampers the assessment of their diversity and evolutionary trends. Moreover, the within-host processes that govern parasitoid infection, development and reproduction are often unknown. In this study, we describe a new specie...

Maximum likelihood phylogenetic tree inferred from the LSU rDNA phylogeny. Sequences of ciliates served as the outgroup. Sequence of Dinovorax pyriformis obtained in this study is indicated in bold and the shaded area encompasses Parviluciferaceae members. The bootstrap values (BS) and Bayesian posterior probabilities (BPP) are provided at each nod...

Zoospores of Dinovorax pyriformis being released through the germ-tube of the sporangium.

Two days time-lapse of infection development of Dinovorax pyriformis on the dinoflagellate Prorocentrum micans.

Location and date of isolation of Dinovorax pyriformis, Snorkelia sp. and Parvilucifera corolla strains, with a detail of strains used for morphological and ultrastructural observations presented, and the correspondence of genetic sequences obtained.

Bysmatrum subsalsum is a cosmopolitan dinoflagellate species that inhabits marine and transitional habitats. Despite its wide distribution, information on the morphological variability, phylogeny and ecology of B. subsalsum is scarce. In this study, we provide morphological and molecular data on B. subsalsum strains and wild cells from different lo...

Recent studies of marine protists have revealed parasites to be key components of marine communities. Here we describe a new species of the parasitoid genus Parvilucifera that was observed infecting the dinoflagellate Durinskia baltica in salt marshes of the Catalan coast (NW Mediterranean). In parallel, the same species was detected after the incu...

Marine environmental monitoring has tended to focus on site-specific methods of investigation. These traditional methods have low spatial and temporal resolution and are relatively labor intensive per unit area/time that they cover. To implement the Marine Strategy Framework Directive (MSFD), European Member States are required to improve marine mo...

Sequencing of rRNA gene polymerase chain reaction amplicons (rRNA tags) is the most common approach for investigating microbial diversity. The recent development of high-throughput sequencing (HTS) technologies has enabled the exploration of microbial biodiversity at an unprecedented scale, greatly expanding our knowledge on the microbiomes of mari...

Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is stron...

Parasites exert important top-down control of their host populations. The host-parasite system formed by Alexandrium minutum (Dinophyceae) and Parvilucifera sinerae (Perkinsozoa) offers an opportunity to advance our knowledge of parasitism in planktonic communities. In this study, DNA extracted from 73 clonal strains of P. sinerae, from 10 differen...

Workshop on Plankton resting stages: ecological, evolutionary and geological perspectives. Tvärminne Zoological Station, Finland. 5-8 October 2015. Planktonic microalgae inhabit freshwater, brackish water and seawater environments and play a key role as phototrophs in the aquatic systems. The life cycles of most microalgal species are complex, wit...

Planktonic microalgae inhabit freshwater, brackish water and seawater environments and play a key role as phototrophs in the aquatic systems. The life cycles of most microalgal species are complex, with stages characterized by radically different morphologies and highly diverse environmental interactions. The two most common life stages are plankto...

The innershelf is a transitional, highly variable and productive area being also relevant for the physical, chemical, and biological processes and the transport of nutrients, plankton, and sediment offshore. This region contains well differentiated ecosystems spatially structured as cross-shore gradients. In low energy environments such as many Med...

In what degree nearshore plankton communities constitute an independent and distinct assemblage from shelf assemblages is a challenging question. Obvious physical and chemical differences exist among both systems but, also, important exchange and interdependencies are depicted by physical forcing. Clues to answer this question can be inferred by an...

The DPSIR (drivers-pressures-state-impact-responses) framework is used to analyze the causal relationships between environmental and human systems and to report on environmental issues. The effective use of the DPSIR approach requires the accurate assessment of pressures. For coastal waters, although several methods have been evaluated, most of the...

We investigated the species-specific phosphorus (P) nutritional strategies in the microphytoplankton community in the Mahon estuary (Minorca, Western Mediterranean) in 2011, under two contrasting hydrographic scenarios. Estuarine flow, nutrient concentrations, phytoplankton community composition, and enzyme-labeled fluorescence (ELF) were measured...

The Water Framework Directive (WFD) mandates the use of biological quality element (BQE) phytoplankton to assess the ecological status of coastal and transitional water bodies (WB). Here, we present (i) a critique of the general ecological assumptions of the WFD, (ii) a review of the ecological features of coastal phytoplankton dynamics, (iii) seve...

Chapter available at => https://doi.org/10.1007/698_2015_392

The diversity and phylogeny of dinoflagellates belonging to the Gymnodiniales were studied during a 3-year period at several coastal stations along the Catalan coast (NW Mediterranean) by combining analyses of their morphological features with rDNA sequencing. This approach resulted in the detection of 59 different morphospecies, 13 of which were o...

The dynamics and consequences of host–parasite coevolution depend on the nature of host genotype-by-parasite genotype interactions (G × G) for host and parasite fitness. G × G with crossing reaction norms can yield cyclic dynamics of allele frequencies (“Red Queen” dynamics) while G × G where the variance among host genotypes differs between parasi...

Environmental 18S rRNA gene surveys of microbial eukaryotes have recently revealed the diversity of major parasitic agents in pelagic freshwater systems, consisting primarily of chytrid fungi. To date, only a few studies have reported the presence of chydrids in the marine environment and a limited number of marine chytrids have been properly ident...

Within the DEVOTES project, a catalogue of existing indicators of marine biodiversity and closely related topics such as non-indigenous species, food-webs, and seafloor integrity (EU Marine Strategy MSFD Descriptors 1, 2, 4, 6) has been established. Currently, the catalogue includes 557 entries with information on metadata ranging from indicator de...

The present study identified and quantified dinoflagellate cysts in surface sediments from three Mediterranean lagoons. Sediment samples were recovered from 11 stations in May 2009 at Cabras Lagoon, eight stations in May 2010 at Corru S'Ittiri Lagoon, and five stations in May 2011 at Santa Giusta Lagoon. Fifty-three dinoflagellate cyst morphotypes...

The order Gymnodiniales comprises unarmoured dinoflagellates. However, the lack of sequences hindered determining the phylogenetic positions and systematic relationships of several gymnodinioid taxa. In this study, a monophyletic clade was defined for the species Ceratoperidinium margalefii Loeblich III, Gyrodinium falcatum Kofoid & Swezy, three Co...

Although the diversity of dinoflagellates has been intensively studied in several locations in the Mediterranean Sea since the 1950s, it is only during the last two decades that the morphotype of the toxic unarmoured dinoflagellate Cochlodinium polykrikoides Margalef has been detected, coinciding with its apparent worldwide expansion in marine coas...

Parasitoids are a major top-down cause of mortality of coastal harmful algae, but the mechanisms and strategies they have evolved to efficiently infect ephemeral blooms are largely unknown. Here, we show that the generalist dinoflagellate parasitoid Parvilucifera sinerae (Perkinsozoa, Alveolata) is activated from dormancy, not only by Alexandrium m...

The study of the ecology and palaeoecology of dinoflagellates and their cysts has made momentous progress since they were first discovered and described. With the help of field studies, their ecological affinities have been established; in parallel, laboratory studies have facilitated progress on the understanding of their life cycle and enabled th...

The principal fatty acids from the lipid profiles of two autochthonous dinoflagellates (Alexandrium minutum and Karlodinium veneficum) and one raphidophyte (Heterosigma akashiwo) maintained in bubble column photobioreactors under outdoor culture conditions are described for the first time. The biomass production, lipid content and lipid productivit...

Knowledge of the specific life-cycle dynamics during harmful algal bloom (HAB) development is essential for understanding and forecasting the onset, evolution and future occurrence of these events. Life-cycle stages of the toxic dinoflagellate Alexandrium fundyense were monitored both in the water column and in the sediments from the onset to the d...

Life-cycle transitions play a key role in the bloom dynamics of many dinoflagellates. In this study, in situ excystment and encystment were monitored during recurrent Alexandrium minutum blooms in Arenys de Mar harbor (NW Mediterranean Sea) from October 2005 to May 2008. In addition, the dynamics of vegetative cells in the water column and resting...