Rodrigo Almeda

University of Las Palmas de Gran Canaria | ULPGC · Department of Biology

Microplastics (MPs) overlap in size with phytoplankton and can be ingested by zooplankton, transferring them to higher trophic levels. Copepods are the most abundant metazoans among zooplankton and the main link between primary producers and higher trophic levels. Ingestion of MPs has been investigated in the laboratory, but we still know little ab...

Metamorphosis is a critical process in the life cycle of most marine benthic invertebrates, determining their transition from plankton to benthos. It affects dispersal and settlement and therefore decisively influences the dynamics of marine invertebrate populations. An extended period of metamorphic competence is an adaptive feature of numerous in...

Major oil spills can impose a significant environmental hazard on the marine ecosystem, and a promising mitigation measure is in-situ oil burning (ISB). However, our knowledge of the impact of the burned residues and soot deposition on the marine ecosystem is still limited. We investigated the effects of burned oil residue and soot deposition on th...

Over the past decade, microplastic research on ingestion and impacts in marine biota has received significant attention. Zooplankton has become a subject of interest due to their crucial role in marine food webs. This review focuses on trends in nano-and microplastics (NMPs) ingestion studies in marine zooplankton. Four groups of organisms were con...

Microplastics (MPs) have emerged as an important research topic due to their ubiquity in the environment and their potentially harmful effects on aquatic biota. However, our knowledge of the abundance and characteristics of the smaller fraction of MPs (<300 μm) in marine waters remains limited. This study aims to compare two different filter pump d...

As plastic debris breaks down in environments, it forms micro(nano) plastics that threaten organisms across ecosystems. These tiny particles are potentially harmful due to industrial additives ingested by organisms. Given the growing concern related to micro(nano) plastics, this study compared the toxicity of leachate from tire wear particles (TWPs...

The progressive establishment of gas platforms and increasing petroleum accidents pose a threat to zooplankton communities and thus to pelagic ecosystems. This study is the first to compare the impacts of gas-condensate and crude oil on copepod assemblages. We conducted microcosm experiments simulating slick scenarios at five different concentratio...

Tire wear particles (TWP) stand out as a major contributor to microplastic pollution, yet their environmental impact remains inadequately understood. This study delves into the cocktail effects of TWP leachates, employing molecular, cellular, and organismal assessments on diverse biological models. Extracted in artificial seawater and analyzed for...

Microplastics (MPs) are ubiquitous pollutants of increasing concern in aquatic systems. However, little is still known about the impacts of weathered MPs on plankton at the community level after long-term exposure. In this study, we investigated the effects of weathered MPs on the structure and dynamics of a Baltic Sea planktonic community during c...

Microplastics (MPs) have emerged as an important research topic due to their ubiquity in the environment and their potentially harmful effects on aquatic biota. However, our knowledge of the abundance and characteristics of the smaller fraction of MPs (<300 µm) in marine waters remains limited. This study aims to compare two different filter pump d...

With thousands of tons of Tyre Wear Particles (TWP) entering the aquatic environment every year, TWP are considered a major contributor to microplastic pollution. TWP leach organic compounds and metals in water, potentially affecting the marine food web. However, little is known about the toxicity of TWP leachates on marine copepods, a major food w...

Particles from tires are a major fraction of microplastic pollution. They contain a wide range of chemical additives that can leach into the water and be harmful to aquatic organisms. In this study, we investigated the acute toxicity of tire particle leachates in early life stages of three keystone echinoderm species (Paracentrotus lividus, Arbacia...

In this study, we investigated the concentration, distribution, and characteristics of neustonic MPs in the Canary Islands, with a particular focus on the island leeward zones, where a high accumulation of floating marine microplastics is expected. Samples were collected with a manta net at 15 different sites from Alegranza to La Gomera during the...

Plastics contain various types and amounts of additives that can leach into the water column when entering aquatic ecosystems. Some leached plastic additives are hazardous to marine biota at environmentally relevant concentrations. Disparate methodological approaches have been adopted for toxicity testing of plastic leachates, making comparison dif...

Microplastics (MPs) are ubiquitous pollutants in the ocean, and there is a general concern about their persistence and potential effects on marine ecosystems. We still know little about the smaller size-fraction of marine MPs (MPs <300 μm), which are not collected with standard nets for MPs monitoring (e.g., Manta net). This study aims to determine...

The entry of microplastics (MPs) into marine food webs is a major environmental concern. We investigated how the behavior of planktonic copepods influences the risk of MPs to enter marine food webs by applying a trait-based approach and by combining experiments (bottle incubations and video observations) with biogeographical analyses. We aimed to e...

Tyre wear particles (TWP) are some of the dominant sources of microplastics in the aquatic environment. Once TWP enter aquatic systems, they can leach certain plastic additives that can be potentially toxic to biota. However, little is known about the impact of TWP lixiviates on marine phytoplankton, the base of marine food webs. This study aims to...

Arctic sea ice has alarmingly high concentrations of microplastics (MPs). Additionally, sea ice reduction in the Arctic is opening new opportunities for the oil and maritime industries, which could increase oil pollution in the region. Yet knowledge of the effects of co-exposure to MPs and crude oil on Arctic zooplankton is lacking. We tested the i...

Microplastics (MPs) are contaminants of emerging concern in the Arctic, but knowledge of their potential effects on Arctic plankton food webs remains scarce. We experimentally investigated the ingestion and effects of MPs (20 μm polyethylene spheres) on the arctic copepods Calanus finmarchicus, C. glacialis and C. hyperboreus. These species dominat...

Microplastics (MPs) are polluting the Arctic, but our understanding of their abundance, distribution, and sources is limited. This study quantified MPs down to 10 μm in marine waters of the most populated region in Greenland. A new plastic-free pump-filter system was used to collect MPs from surface waters in the fjord Nuup Kangerlua close to Nuuk....

Diatoms contribute nearly half of the marine primary production. These microalgae differ from other phytoplankton groups in having a silicified cell wall, which is the strongest known biological material relative to its density. While it has been suggested that a siliceous wall may have evolved as a mechanical protection against grazing, empirical...

It is well known that mussels are exposed to microplastics but ingestion and potential effects on mussel larvae are not well understood. We quantified ingestion and egestion of 100 nm and 2 μm polystyrene beads in blue mussel larvae after 4 h exposure and 16 h depuration using different plastic-to-microalgae ratios. Effects on growth and developmen...

Our traditional view of the interactions between marine organisms is conceptualized as food webs where species interact with one another mainly via direct consumption. However, recent research suggests that understudied non-consumptive interactions, such as behaviourally mediated indirect interactions (BMIIs), can influence marine ecosystems as muc...

Size at maturity in ectotherms commonly declines with warming. This near‐universal phenomenon, formalised as the temperature‐size rule, has been observed in over 80% of tested species, from bacteria to fish. The proximate cause has been attributed to the greater temperature dependence of development rate than growth rate, causing individuals to dev...

Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encounte...

The ubiquitous, biogenic trace gas dimethylsulfide (DMS) represents the largest natural source of atmospheric sulfur. Given DMS involvement in cloud formation and climate, understanding and parameterizing the oceanic DMS source and cycling processes is a necessary challenge. We report DMS cycling rates from microzooplankton dilution grazing experim...

The ecological consequences of “sit-and-wait” (ambushing) vs. “searching” (active feeding) foraging strategies are not well-understood in marine plankton food webs. We determined the maximum clearance rates of ambush and active feeders to evaluate the trade-off between foraging gain and predation risk associated with the main foraging strategies in...

Planktonic copepods have sexual dimorphism that can lead to differences in starvation tolerance between genders. Additionally, mating may be energetically costly and thus reduce starvation tolerance. We investigated the influence of sexual dimorphism and mating on starvation tolerance of copepods with different feeding behaviours: Oithona nana (amb...

After oil spills and dispersant applications the formation of red tides or harmful algal blooms (HABs) has been observed, which can cause additional negative impacts in areas affected by oil spills. However, the link between oil spills and HABs is still unknown. Here, we present experimental evidence that demonstrates a connection between oil spill...

Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behavior. Upon encounter...

Marine free living copepods can survive harsh periods and cope with seasonal fluctuations in environmental conditions using resting eggs (embryonic dormancy). Laboratory experiments show that temperature is the common driver for resting egg production. Hence, we hypothesize (i) that seasonal temperature variation, rather than variation in food abun...

Planktonic copepods have sexually dimorphic behaviors, which can cause differences in feeding efficiency between genders. Copepod feeding rates have been studied extensively but most studies have focused only on females. In this study, we experimentally quantified feeding rates of males and females in copepods with different feeding behavior: ambus...

Predation is an important source of mortality in zooplankton but factors governing predation risk in marine food webs are still not well understood. Here, we examine the role of zooplankton behavior in determining predation risk. We first quantified motility of copepods with different feeding behaviors (ambush feeding, cruising, and feeding-current...

Zooplankton exhibit different small-scale motile behaviors related to feeding and mating activities. These different motile behaviors may result in different levels of predation risk, which may partially determine the structure of planktonic communities. Here, we experimentally determined predation mortality associated with (1) feeding activity (am...

Toxic effects of petroleum to marine zooplankton have been generally investigated using dissolved petroleum hydrocarbons and in the absence of sunlight. In this study, we determined the influence of natural ultraviolet B (UVB) radiation on the lethal and sublethal toxicity of dispersed crude oil to naupliar stages of the planktonic copepods Acartia...

We investigated and quantified defecation rates of crude oil by 3 species of marine planktonic copepods (Temora turbinata, Acartia tonsa, and Parvocalanus crassirostris) and a natural copepod assemblage after exposure to mechanically or chemically dispersed crude oil. Between 88 and 100% of the analyzed fecal pellets from three species of copepods...

Although planktonic protozoans are likely to interact with dispersed crude oil after a spill, protozoan-mediated processes affecting crude oil pollution in the sea are still not well known. Here, we present the first evidence of ingestion and defecation of physically or chemically dispersed crude oil droplets (1-86 μm in diameter) by heterotrophic...

The metabolic carbon requirements and excretion rates of three major zooplankton groups in the Southern Ocean were studied in February 2009. The research was conducted in the framework of the ATOS research project as part of the Spanish contribution to the International Polar Year. The objective was to ascertain the possible consequences of the pre...

Planktonic copepods play a key function in marine ecosystems, however, little is known about the effects of dispersants and chemically dispersed crude oil on these important planktonic organisms. We examined the potential for the copepods Acartia tonsa, Temora turbinata and Parvocalanus crassirostris to ingest crude oil droplets and determined the...