Not Only Toxic but Repellent: What Can Organisms’ Responses Tell Us about Contamination and What Are the Ecological Consequences When They Flee from an Environment?

The APC was funded by the Spanish Ministry of Science and Innovation. C.V.M.A. received the Ramón y Cajal contract (RYC-2017-22324) from the Spanish Ministry of Science and Innovation. This study was performed within the framework of the projects: MultiCecotox project (i-COOP2019 program from CSIC: #COOPB20444) and BrEStress project (PID2019-105868RA-I00) and CaPETHaS project (Explora call: #CGL2017-92160-EXP)—both funded by the Spanish Ministry of Science and Innovation).The ability of aquatic organisms to sense the surrounding environment chemically and interpret such signals correctly is crucial for their ecological niche and survival. Although it is an oversimplification of the ecological interactions, we could consider that a significant part of the decisions taken by organisms are, to some extent, chemically driven. Accordingly, chemical contamination might interfere in the way organisms behave and interact with the environment. Just as any environmental factor, contamination can make a habitat less attractive or even unsuitable to accommodate life, conditioning to some degree the decision of organisms to stay in, or move from, an ecosystem. If we consider that contamination is not always spatially homogeneous and that many organisms can avoid it, the ability of contaminants to repel organisms should also be of concern. Thus, in this critical review, we have discussed the dual role of contamination: toxicity (disruption of the physiological and behavioral homeostasis) vs. repellency (contamination-driven changes in spatial distribution/habitat selection). The discussion is centered on methodologies (forced exposure against non-forced multi-compartmented exposure systems) and conceptual improvements (individual stress due to the toxic effects caused by a continuous exposure against contamination-driven spatial distribution). Finally, we propose an approach in which Stress and Landscape Ecology could be integrated with each other to improve our understanding of the threat contaminants represent to aquatic ecosystems.Spanish Ministry of Science and Innovation (RYC-2017-22324), (PID2019-105868RA-I00), (#CGL2017-92160-EXP)CSIC: #COOPB2044

Effects and Risk Assessment of the Polycyclic Musk Compounds Galaxolide (R) and Tonalide (R) on Marine Microalgae, Invertebrates, and Fish

The current research investigated the potential environmental risk of the polycyclic musk compounds, Galaxolide (R) (HHCB) and Tonalide (R) (AHTN), in the marine environments. These substances are lipophilic, bioaccumulated, and potentially biomagnified in aquatic organisms. To understand the toxicity of HHCB and AHTN, acute toxicity tests were performed by exposing marine microalgae (Phaeodactylum tricornutum, Tretraselmis chuii, and Isochrysis galbana), crustaceans (Artemia franciscana), echinoderms (Paracentrotus lividus), bivalves (Mytilus galloprovincialis), fish (Sparus aurata), and a candidate freshwater microalga (Raphidocelis subcapitata) to environmentally relevant concentrations (0.005-5 mu g/L) following standardized protocols (US EPA, Environment Canada and OECD). P. tricornutum and I. galbana were sensitive to both substances and for P. tricornutum exposed to HHCB and AHTN, the IC10 values (the inhibition concentration at which 10% microalgae growth inhibition was observed) were 0.127 and 0.002 mu g/L, respectively, while IC10 values calculated for I. galbana were 5.22 mu g/L (a little higher than the highest concentration) and 0.328 mu g/L, for HHCB and AHTN, respectively. Significant (p < 0.01) concentration dependent responses were measured in P. lividus and M. galloprovincialis larvae developments, as well as S. aurata mortality tested with HHCB. The effect of HHCB on P. lividus larvae development was the most sensitive endpoint recorded, producing an EC50 value (the effect concentration at which 50% effect was observed) of 4.063 mu g/L. Considering the risk quotients both substances seem to represent high environmental risk to P. tricornutum and M. galloprovincialis in marine environments

Sigmatropic rearrangements in 5-allyloxytetrazoles

Mechanisms of thermal isomerization of allyl tetrazolyl ethers derived from the carbocyclic allylic alcohols cyclohex-2-enol and 3-methylcyclohex-2-enol and from the natural terpene alcohol nerol were investigated. In the process of the syntheses of the three 1-aryl-5-allyloxytetrazoles, their rapid isomerization to the corresponding 1-aryl-4-allyltetrazol-5-ones occurred. The experiments showed that the imidates rearrange exclusively through a [3,3¢]-sigmatropic migration of the allylic system from O to N, with inversion. Mechanistic proposals are based on product analysis and extensive quantum chemical calculations at the DFT(B3LYP) and MP2 levels, on O-allyl and N-allyl isomers and on putative transition state structures for [1,3¢]- and [3,3¢]-sigmatropic migrations. The experimental observations could be only explained on the basis of the MP2/6-31G(d,p) calculations that favoured the [3,3¢]-sigmatropic migrations, yielding lower energies both for the transition states and for the final isomerization products

Efectos de la salinidad sobre el crecimiento, la fluorescencia de clorofila y el drift de la microalga bentónica Cylindrotheca closterium

Trabajo presentado en el XVII Iberian Symposium on Marine Biology Studies, celebrado en San Sebastián del 11 a 14 de septiembre de 2012.En el presente trabajo se evaluó el efecto de la salinidad sobre el crecimiento poblacional, la fluorescencia de clorofila y el drift (desplazamiento pasivo en la corriente de agua) de Cylindrotheca closterium. C. closterium es una microalga bentónica que habita zonas estuarinas formando parte del microfitobentos. Entre los factores de estrés que pueden afectar a la especie C. closterium se encuentran los cambios de salinidad. En una primera fase, estos efectos se evaluaron en base al crecimiento poblacional en ensayos de toxicidad estándar realizados en matraz. Las células de C. closterium fueron expuestas a diferentes salinidades, que variaron de 37 (control) hasta 5, durante 72 h, bajo condiciones controladas temperatura y luz constante. El drift y la fluorescencia de clorofila se midieron simultáneamente como marcadores de exposición al estrés. Para ello se diseñó y construyó un sistema de flujo continuo (Figura 1) que permitiera examinar la capacidad de C. closterium de evitar los efectos de la salinidad mediante el drift. El sistema estaba compuesto de 3 compartimentos interconectados de 35 mL cada uno. Los dos compartimentos iniciales fueron usados para reducir la turbulencia del agua y evitar el arrastre de las microalgas colocadas en el tercer compartimento. Un flujo de agua constante de 480±15 mL min-1 era generado mediante una bomba contenida en un recipiente donde era recogida el agua una vez salía del sistema, creando así un circuito cerrado y continuo. La entrada de agua de la bomba fue cubierta con un filtro de 5 µm de luz de malla para evitar que las microalgas que realizaban drift retornaran al sistema. El circuito contenía 500 mL de agua de mar filtrada a la que se añadió medio f/2 y silicatos. Seis horas antes del inicio del ensayo se colocaban las microalgas, con una concentración de 104 células mL-1, en el tercer compartimento del sistema para garantizar que estas decantaran en el fondo. A continuación el sistema era puesto en marcha durante 12 h y en oscuridad para evitar el crecimiento de la población de microalgas. Se realizaron ensayos a diferentes salinidades (37, 30, 24, 19, 15, 12 y 9) que fueron repetidos cuatro veces en el tiempo. El número de células que hizo drift fue determinado en función de la fluorescencia de clorofila de modo que ambas respuestas, drift y reducción en la fluorescencia de clorofila fueron integradas en una misma medida. Los datos de inhibición de crecimiento indican que la salinidad que causa una reducción en la población del 50% (ES50) fue de 19±4; por otro lado la ES50 calculada a partir del sistema de drift integrando la fuga y la fluorescencia de clorofila fue de 15±3. Los resultados del estudio mostraron que un descenso de la salinidad provoca una disminución en el crecimiento de C. closterium, además produce una disminución en la fluorescencia de clorofila y desencadena la respuesta de drift.Peer Reviewe

Not Only Toxic but Repellent: What Can Organisms’ Responses Tell Us about Contamination and What Are the Ecological Consequences When They Flee from an Environment?

The ability of aquatic organisms to sense the surrounding environment chemically and interpret such signals correctly is crucial for their ecological niche and survival. Although it is an oversimplification of the ecological interactions, we could consider that a significant part of the decisions taken by organisms are, to some extent, chemically driven. Accordingly, chemical contamination might interfere in the way organisms behave and interact with the environment. Just as any environmental factor, contamination can make a habitat less attractive or even unsuitable to accommodate life, conditioning to some degree the decision of organisms to stay in, or move from, an ecosystem. If we consider that contamination is not always spatially homogeneous and that many organisms can avoid it, the ability of contaminants to repel organisms should also be of concern. Thus, in this critical review, we have discussed the dual role of contamination: toxicity (disruption of the physiological and behavioral homeostasis) vs. repellency (contamination-driven changes in spatial distribution/habitat selection). The discussion is centered on methodologies (forced exposure against non-forced multi-compartmented exposure systems) and conceptual improvements (individual stress due to the toxic effects caused by a continuous exposure against contamination-driven spatial distribution). Finally, we propose an approach in which Stress and Landscape Ecology could be integrated with each other to improve our understanding of the threat contaminants represent to aquatic ecosystems.Versión del edito

Cold atoms in space: community workshop summary and proposed road-map

We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies

Cold atoms in space: community workshop summary and proposed road-map

We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies