Microplastic retention by marine vegetated canopies: simulations with seagrass meadows in a hydraulic flume

Marine canopies formed by seagrass and other coastal vegetated ecosystems could act as sinks of microplastics for being efficient particle traps. Here we investigated for the first time the occurrence of microplastic retention by marine canopies in a hydraulic flume under unidirectional flow velocities from 2 to 30 cm s-1. We used as model canopy-forming species the seagrass Zostera marina with four canopy shoot density (0, 50, 100, 200 shoots m-2), and we used as microplastic particles industrial pristine pellets with specific densities from 0.90 to 1.34 g cm-3 (polypropylene PP; polystyrene PS; polyamide 6 PA; and polyethylene terephthalate PET). Overall, microplastics particles transported with the flow were retained in the seagrass canopies but not in bare sand. While seagrass canopies retained floating microplastics (PP) only at low velocities (<12 cm s-1) due to a barrier created by the canopy touching the water surface, the retention of sinking particles (PS, PA, PET) occurred across a wider range of flow velocities. Our simulations revealed that less dense sinking particles (PS) might escape from the canopy at high velocities, while denser sinking particles can be trapped in scouring areas created by erosive processes around the eelgrass shoots. Our results show that marine canopies might act as potential barriers or sinks for microplastics at certain bio-physical conditions, with the probability of retention generally increasing with the seagrass shoot density and polymer specific density and decreasing with the flow velocity. We conclude that seagrass meadows, and other aquatic canopy-forming ecosystems, should be prioritized habitats in assessment of microplastic exposure and impact on coastal areas since they may accumulate high concentration of microplastic particles that could affect associated fauna.FCT: UIDB/04326/2020/ SFRH/BPD/119344/2016info:eu-repo/semantics/publishedVersio

Coastal ecosystem engineers and their impact on sediment dynamics: Eelgrass–bivalve interactions under wave exposure

Habitat forming ecosystem engineers play critical roles in structuring coastal seascapes. Many ecosystem engineers, such as seagrasses and epifaunal bivalves, are known to have positive effects on sediment stability and increase coastal protection and ecosystem resilience. Others, such as bioturbating infaunal bivalves, may instead destabilize sediment. However, despite the common co-occurrence of seagrasses and bivalves in coastal seascapes, little is known of their combined effects on sediment dynamics. Here, we used wave flumes to compare sediment dynamics in monospecific and multispecific treatments of eelgrass, Zostera marina, and associated bivalves (infaunal Limecola balthica, infaunal Cerastoderma edule, epifaunal Magellana gigas) under a range of wave exposures. Eelgrass reduced bedload erosion rates by 25–50%, with digital elevation models indicating that eelgrass affected the sediment micro-bathymetry by decreasing surface roughness and ripple sizes. Effects of bivalves on sediment mobilization were species-specific; L. balthica reduced erosion by 25%, C. edule increased erosion by 40%, while M. gigas had little effect. Importantly, eelgrass modified the impacts of bivalves: the destabilizing effects of C. edule vanished in the presence of eelgrass, while we found positive additive effects of eelgrass and L. balthica on sediment stabilization and potential for mutual anchoring. Such interspecific interactions are likely relevant for habitat patch emergence and resilience to extreme wave conditions. In light of future climate scenarios where increasing storm frequency and wave exposure threaten coastal ecosystems, our results add a mechanistic understanding of sediment dynamics and interactions between ecosystem engineers, with relevance for management and conservation.publishedVersio

Assessing Tolerance to the Hydrodynamic Exposure of Posidonia oceanica Seedlings Anchored to Rocky Substrates

Among a suite of abiotic and biotic factors, the hydrodynamic regime strongly influences the success of seagrass recruitment through sexual propagules. Uprooting of propagules by drag forces exerted by currents and waves is one of the main causes for the failed establishment and the consequent recruitment. Substrate type and stability play a key role in determining the success of colonization through sexual propagules, as seedling establishment probabilities proved to be significantly higher on rocky bottoms than on unstable unconsolidated substrates. In this research, the current and wave flow intensity that Posidonia oceanica seedlings anchored to rocky substrates can withstand before uprooting were evaluated and the influence of substrate complexity on seedling anchorage success and anchorage strength was investigated. P. oceanica seedlings withstood the current velocity of 70 cm s–1 and increased orbital flow velocities up to 25 cm s–1. Seedling adhesion strength ranged from 3.92 to 29.42 N. Results of the present study corroborate the hypothesis that substrate complexity at scales relevant to the size of propagules is a crucial feature for P. oceanica seedling establishment. The intensity of unidirectional and oscillatory flow that seedlings can withstand without being dislodged assessed in this study support the hypothesis that P. oceanica sexual propagules, once adhered to a consolidated substrate, are able to tolerate high hydrodynamic stress. The results of the present study contribute to re-evaluation of the habitat requirements of P. oceanica, assessing the range of hydrodynamic conditions that this species can tolerate during the early stages of its life history

Severe shifts of Zostera marina epifauna: comparative study between 1997 and 2018 on the Swedish Skagerrak coast

The interaction between bottom-up and top-down processes in coastal ecosystems has been scarcely studied so far. Temporal changes in trophic interactions of Zostera marina along the Swedish west coast are relatively well studied, with the exception of epifaunal communities. Epifauna was used as a model study to explore resource (bottom-up) or predator (top-down) regulated in a vegetated ecosystem. We conducted a 21-year comparative study (1997 and 2018) using epifauna of 19 Zostera marina meadows along the Swedish Skagerrak coast. Large changes were observed in the composition of small (0.2–1 mm) and large (> 1 mm) epifauna. In the small-sized epifauna, the nematode Southernia zosterae and harpacticoids showed an increase of 90% and a decrease of 50% of their abundances, respectively. In the large-sized epifauna, the polychaete Platynereis dumerilii and chironomid larvae were absent in 1997 but thrived in 2018 (> 2000 ind. m−2 ). Mesoherbivores (Idoteids and gammarids) were locally very abundant in 1997 but disappeared in 2018. An 83% decline of mytilids settling in Zostera marina leaves was observed. Our results showed that epifauna is predominantly top-down regulated. An in tegrative framework of the study area is outlined to shed light on the causes and consequences of the en vironmental shifts reported in Zostera meadows from the northern Skagerrak area throughout the last three decades.info:eu-repo/semantics/publishedVersio

Restaurering av ålegrasenger: En praktisk veileder utviklet for Oslo kommune

Prosjektleder Kristina Øie KvileÅlegrasenger er marine undervannsenger som finnes på grunne bløtbunnsområder langs Norskekysten, inkludert i Oslofjorden. De utgjør en viktig naturtype som huser et rikt biologisk mangfold og produserer en rekke økosystemtjenester. Klimaetaten i Oslo kommune ønsket en utredning av kunnskapsgrunnlaget og kartlegging av muligheter for restaurering eller reintroduksjon av ålegrasenger, og hvordan det vil påvirke karbonopptak og klimatilpasning i Oslofjorden. I tillegg ønsket de en praktisk veileder om reintroduksjon og restaurering av ålegras. Denne veilederen inneholder en detaljert steg-for-steg beskrivelse av hvordan restaurering kan gjennomføres i praksis, og dekker i) valg av område for restaurering, ii) planting og iii) overvåking. Kunnskap om ålegrasenger og deres rolle for karbonopptak og klimatilpasning er presentert i en egen rapport (Kvile et al. 2022).publishedVersio

Effects of palmitoylethanolamide in cocaine-induced behaviours

Aims. Cocaine addiction is a chronically relapsing disorder characterized by the compulsion to seek and take the drug. Previous investigations have demonstrated that several drugs of abuse, as cocaine, can alter the levels of lipid-based signalling molecules such as the N-acylethanolamines (NAEs). In addition, NAEs levels in the brain are sensitive to cocaine self-administration and extinction training. In this context, this study aimed to investigate the effect of repeated and acute palmitoylethanolamide (PEA), an endogenous NAE, on the behavioural effects of cocaine using mouse models of conditioned reward and psychomotor activation. Methods. Using male C57BL/6J mice, the ability of repeated PEA injections (1 or 10 mg/kg i.p) to modulate the development of a conditioned place preference (CPP) and behavioural sensitization (BS) induced by cocaine (20 mg/kg i.p.) was evaluated. In addition, the expression of cocaine-induced CPP and BS after acute PEA administration was also studied. Results. PEA (1 and 10 mg/kg i.p) significantly reduced the development of cocaine-induced BS, but did not modify the acquisition of cocaine-induced CPP. Furthermore, both doses of PEA were able to reduce the expression of BS and CPP. Conclusions. Altogether, these findings show that exogenous administration of PEA attenuated psychomotor activation and impaired the expression of CPP induced by cocaine. Our results may be relevant in order to understand the role of NAEs in the development and treatment of cocaine addiction.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. PSI2013-44901-P, AP2010-2044, FPU13/04819, CD12/0045

High seasonal variability in sediment carbon stocks of cold‐temperate seagrass meadows

Seagrass meadows have a high ability to capture and store atmospheric CO2 in the plant biomass and underlying sediment and thereby function as efficient carbon sinks. The seagrass Zostera marina is a common species in the temperate Northern Hemisphere, a region with strong seasonal variations in climate. How seasonality affects carbon storage capacity in seagrass meadows is largely unknown, and therefore, in this study, we aimed to assess variations in sedimentary total organic carbon (TOC) content over a 1‐year cycle in seagrass meadows on the Swedish west coast. The TOC was measured in two Z. marina sites, one wave exposed and one sheltered, and at two depths (1.5 and 4 m) within each site, every second month from August 2015 to June 2016. We found a strong seasonal variation in carbon density, with a peak in early summer (June), and that the TOC was negatively correlated to the net community production of the meadows, presumably related to organic matter degradation. There was seasonal variation in TOC content at all sediment sections, indicating that the carbon content down to 30 cm is unstable on a seasonal scale and therefore likely not a long‐term carbon sink. The yearly mean carbon stocks were substantially higher in the sheltered meadow (3,965 and 3,465 g m−2) compared to the exposed one (2,712 and 1,054 g m−2) with similar seasonal variation. Due to the large intra‐annual variability in TOC content, seasonal variation should be considered in carbon stock assessments and management for cold‐temperate seagrass meadows.info:eu-repo/semantics/publishedVersio

Wave energy and the upper depth limit distribution of Posidonia oceanica

Abstract It is widely accepted that light availability sets the lower limit of seagrass bathymetric distribution, while the upper limit depends on the level of disturbance by currents and waves. The establishment of light requirements for seagrass growth has been a major focus of research in marine ecology, and different quantitative models provide predictions for seagrass lower depth limits. In contrast, the influence of energy levels on the establishment, growth, and maintenance of seagrasses has received less attention, and to date there are no quantitative models predicting the evolution of seagrasses as a function of hydrodynamics at a large scale level. Hence, it is not possible to predict either the upper depth limit of the distribution of seagrasses or the effects that different energy regimes will have on these limits. The aim of this work is to provide a comprehensible methodology for obtaining quantitative knowledge and predictive capacity for estimating the upper depth limit of seagrasses as a response to wave energy dissipated on the seafloor. The methodology has been applied using wave data from 1958 to 2001 in order to obtain the mean wave climate in deep water seaward from an open sandy beach in the Balearic Islands, western Mediterranean Sea where the seagrass Posidonia oceanica forms an extensive meadow. Mean wave conditions were propagated to the shore using a two-dimensional parabolic model over the detailed bathymetry. The resulting hydrodynamics were correlated with bottom type and the distribution of P. oceanica. Results showed a predicted near-bottom orbital velocity of between 38 and 42 cm s -1 as a determinant of the upper depth limit of P. oceanica. This work shows the importance of interdisciplinary effort in ecological modeling and, in particular, the need for hydrodynamical studies to elucidate the distribution of seagrasses in shallow depths. Moreover, the use of predictive models would permit evaluation of the effects of coastal activities (construction of ports, artificial reefs, beach nutrientinput, dredging) on benthic ecosystems

Potensial for restaurering og reintroduksjon av ålegrasenger i Oslofjorden, og mulighetene dette kan gi for klimatilpasning, karbonopptak og lagring

Prosjektleder Kristina Øie KvileÅlegrasenger er en viktig naturtype som huser et rikt biologisk mangfold og bidrar med en rekke økosystemtjenester, inkludert opptak og lagring av CO2. Klimaetaten i Oslo kommune ønsket en utredning av kunnskapsgrunnlaget og kartlegging av muligheter for restaurering eller reintroduksjon av ålegrasenger i sine sjøområder, og hvordan dette vil påvirke karbonopptak og klimatilpasning i Oslofjorden. I denne rapporten presenteres gjeldende kunnskap om ålegrasenger og deres økosystemtjenester og rolle for karbonopptak og klimatilpasning. Trusler mot ålegrasenger og hvordan restaurering av ålegrasenger kan motvirke de negative trendene, er også vurdert, med fokus på kystområdene innenfor Oslo kommunes grenser. Relevante lover og regler i forbindelse med restaurering blir også diskutert. I oktober 2021 gjennomførte NIVA en befaring for å undersøke relevante områder for restaurering, som er presentert i denne rapporten. En detaljert beskrivelse av hvordan restaurering kan gjennomføres presenteres i en egen rapport.publishedVersio

VISTAS GENERALES [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201