Examinando por Autor "Olabarria, Celia"

Mostrando 1 - 7 de 7

Are clam-seagrass interactions affected by heatwaves during emersion?
(Elsevier, 2023-04) Román, Marta; Gilbert, Franck; Viejo, Rosa M.; Román, Salvador; Troncoso, Jesús S.; Vázquez, Elsa; Olabarria, Celia
The increased frequency of heatwaves expected in the context of global warming will affect socio-ecological systems such as shellfish beds at intertidal seagrass meadows. A mesocosm experiment was performed to assess the effects of a simulated atmospheric heatwave during low tide on the bioturbation indicators and growth of the commercial juvenile native Ruditapes decussatus and the introduced clam R. philippinarum, and on their interactions with the seagrass Zostera noltei. Under the heatwave, heat dissipation at 5 cm depth was significantly greater in the sediments below Z. noltei than below bare sand, the photosynthetic efficiency (Fv/Fm) of Z. noltei decreased and the clams tended to grow less. Furthermore, after the heatwave clams below bare sand tended to burrow deeper than those below Z. noltei, indicating that seagrass provided a refuge for clams. Ruditapes philippinarum grew less, and did not burrow as deeply as R. decussatus, which may imply greater vulnerability to desiccation and heat at low tide. The particle displacement coefficient (PDC) of R. philippinarum indicated lower bioturbation values in Z. noltei than in bare sand and was a suitable bioturbation indicator for juvenile Ruditapes spp. clams. In Z. noltei coexisting with R. philippinarum, the Fv/Fm values were higher than without clams after a recovery period, which may be linked to the assimilation of phosphate excreted by the clams and suggests a facilitative interaction. No such interaction was observed with R. deccusatus, probably because of its deeper burrowing depth. The findings suggest reciprocal facilitative interactions between R. philippinarum and Z. noltei and the potential contribution of Z. noltei to the sustainability of clams under global warming scenarios, which may support management actions aimed at enhancing the coexistence between shellfishing activities and seagrass conservation.
Coexistence of a native and an invasive mussel species across an environmental gradient: Do interactions matter?
(Elsevier, 2024-11) Olabarria, Celia; Viejo, Rosa M.; Vázquez, Elsa
Introductions of invasive species are increasing worldwide, potentially threatening biodiversity. Although invasive species often displace native species by outcompeting them, coexistence between native and non-native species is common in diverse communities. A field experiment investigated the interactions between the native mussel Mytilus galloprovincialis and the invasive black pygmy mussel Xenostrobus securis across an environmental salinity gradient in the Ria de Vigo (NW Spain). The salinity gradient strongly affected the physiological responses of both mussel species as well as the competitive interactions between the two species. Mytilus galloprovincialis had a stronger effect on the invader than vice versa. The competition with M. galloprovincialis and the release from predation in certain estuarine areas may in part explain the dynamics of the invader population in the Ría de Vigo. Furthermore, results suggest that the invader may contribute positively to ecosystem functioning by increasing bentho-pelagic coupling, water-column clearance, and biodeposition of organic material in the innermost parts of estuaries, where it reaches large abundances. These areas are likely to promote and maintain the supply of propagules to the outermost parts, as well as favouring secondary spread along the Galician coast.
Context-dependent resilience of intertidal seagrass and venerid clams after hyposalinity stress
(Inter-Research Science Publisher, 2024-02-22) Román, Marta; Vázquez, Elsa; Viejo, Rosa M; Woodin, Sarah A.; Whetey, David S.; Román, Salvador; Weidberg, Nicolás; Troncoso, Jesús S.; Méndez, María M.; Olabarria, Celia
Reduced salinity in estuarine areas can negatively affect intertidal seagrass meadows where clams are harvested. However, legacy effects of hyposalinity on seagrasses and infaunal clams and on their interactions have seldom been studied. Legacy effects were examined in the intertidal seagrass Zostera noltei and juveniles of the clams Venerupis corrugata, Ruditapes decussatus and R. philippinarum. Low-salinity stress was applied to mesocosms that included assemblages of seagrass and the 3 clam species that were subsequently transplanted to 2 shellfish beds characterized by different environmental conditions (i.e. seawater temperature, salinity and nutrient concentration). After 2 mo, the morphological and biochemical traits of Z. noltei and the growth and mortality of the clams were measured. Past hyposalinity stress increased clam mortality and decreased Z. noltei leaf length. The native V. corrugata was the most vulnerable to past hyposalinity, whereas the introduced clam R. philippinarum was the most resilient. The presence of clams was associated with greater nitrogen content and biomass of the above-ground parts of Z. noltei. Survival of the clams after past hyposalinity stress was greater below Z. noltei than below bare sediment, indicating persistent positive interactions following the harsh environmental conditions and during low-salinity periods in the field. At the colder and more nutrient-rich site, positive interactions were more frequent and Z. noltei performed better. This supported the influence of abiotic conditions on the recovery process. Nonetheless, enhanced survival of clams below Z. noltei indicates that Z. noltei could favour the sustainability of these shellfisheries after exposure to extreme rainfall events.
Differential responses of trailing-edge populations of a foundation alga to thermal stress
(Taylor & Francis, 2021-03-29) García, Ana G.; Olabarria, Celia; Álvarez-Losada, Óscar; Viejo, Rosa M.
Populations within the same species range edge may experience contrasting local conditions and exhibit diverse levels of environmental tolerance. This heterogeneity within a range boundary has seldom been considered in studies forecasting the impact of anthropogenic habitat alteration and climate change on species distributions. Moreover, any ecological prediction under changing environmental conditions requires a good understanding of the combined responses of organisms to multiple stressors, in particular the effects on key life cycle stages of species. The intertidal seaweed Fucus serratus is a dominant species on northern Atlantic shores and whose southern limit is in the NW Iberian Peninsula. We examined how early developmental stages of southern-edge populations of this foundation alga responded to the combined effects of environmental stressors, including salinity and aerial and seawater temperature. Four populations from two different areas of the NW Iberian coast were considered: two populations from open shores on the northern coast and two populations from the western rias on the Atlantic coast. The study findings revealed inter-population variability in the response to heat stress, with greater survival of germlings from the northern populations than those from western rias. Environmental conditions are still more benign within western rias, under the influence of strong summer upwelling events. The results also suggest the key role of aerial thermal stress in determining the southern limit of distribution of the target species. The future of these heterogeneous edge populations from NW Iberian Peninsula depends on trends in climate change and the ability of populations to cope with these. Environmental changes may already be occurring at rates that exceed the plastic and adaptive potential of edge populations in N Spain, while the future of western rias as climate refugia for this and other foundation alga is also uncertain.
Effects of warming on biological interactions between clams and the seagrass Zostera noltei: A case study using open top chambers
(Elsevier, 2022-10) Román, Salvador; Vázquez, Elsa; Román, Marta; Viejo, Rosa M.; Woodin, Sarah A.; Whetey, David S.; Troncoso, Jesús S.; Olabarria, Celia
Bivalves and seagrasses can interact through diverse environmentally-modulated mechanisms. To assess the effects of climate warming on bivalve-seagrass interactions, we carried out a pioneering field experiment in which open top chambers (OTCs) were used to increase air and sediment temperature in a shellfish bed in NW Spain during two consecutive spring tides (16 days of exposure to OTCs). The temperature increase produced by OTCs was significant, as observed in the daily maximum and mean temperature and in degree hours, although the difference was greater in air and at the sediment surface (up to 8 °C and 3 °C, respectively) than at 5 cm depth (up to 1 °C). Warming was less acute in boxes with the seagrass Zostera noltei, which acted as a thermal buffer, reducing the mean temperature by 1 °C at the sediment surface in OTC boxes and control boxes (without OTCs). Although the short-term increase in temperature did not greatly affect physiological responses of Z. noltei, the carbohydrate reserves and nutrient content increased in the presence of clams. Growth of the native clam Ruditapes decussatus was significantly slower in OTC boxes with bare sediment, and the seagrass thus buffered the negative effect of warming on growth. The presence of Z. noltei may save clams from having to spend energy to burrow deeper to encounter cooler conditions, leaving more energy available for growth. Conversely, growth of the introduced clam R. philippinarum did not differ between habitats or treatments. Our findings confirm a two-way facilitative interaction that may be particularly important in relation to the resilience of both species in the current context of global warming.
Removal of an established invader can change gross primary production of native macroalgae and alter carbon flow in intertidal rock pools
(Public Library of Science, 2019-12-03) Rossi, Francesca; Viejo, Rosa M.; Duarte, Linney; Vaz-Pinto, Fátima; Gestoso, Ignacio; Olabarria, Celia
The impact of invasive species on recipient communities can vary with environmental context and across levels of biological complexity. We investigated how an established invasive seaweed species affected the biomass, eco-physiology, carbon and nitrogen storage capacity of native seaweeds at sites with a different environmental setting due to a persistent upwelling in northern Spain. We removed the invasive Japanese wireweed Sargassum muticum from intertidal rock pools once every month during a one-year period and used an in-situ stable isotope pulse-chase labeling to estimate gross primary production (GPP), nitrogen uptake rate, 13C-carbon and 15N-nitrogen storage capacities. Following the addition of 13C-enriched bicarbonate and 15N-enriched nitrate to the seawater in the rock pools during the period of the low tide, we sampled macroalgal thalli at incoming tide to determine label uptake rate. After four days, we sampled macroalgal assemblages to determine both label storage capacity and biomass. After one year of removal there was no change in the macroalgal assemblage. However, both the GPP and 13C-carbon storage capacity were higher in the turf-forming Corallina spp. and, sometimes, in the canopy-forming Bifurcaria bifurcata. Nitrogen uptake rate followed similar, but more variable results. Although S. muticum inhibited carbon storage capacity of native species, the assemblage-level 13C-carbon storage was similar in the S. muticum—removed and control rock pools because the presence of the invasive species compensated for the functional loss of native species, particularly at sites where it was most abundant. No obvious effects were observed in relation to the environmental setting. Overall, the effect of the invasive S. muticum on carbon flow appeared to be mediated both by the effects on resource-use efficiency of native species and by its own biomass. Integrating physiological and assemblage-level responses can provide a broad understanding of how invasive species affect recipient communities and ecosystem functioning.
The stress response of the seagrass Zostera noltei and three commercial clam species to low salinity associated with heavy rainfall
(Oxford University Press, 2024-03) Román, Salvador; Vázquez, Elsa; Román, Marta; Viejo, Rosa M.; Weidberg, Nicolás; Troncoso, Jesús S.; Woodin, Sarah A.; Whetey, David S.; Olabarria, Celia
The maintenance of stocks of estuarine species strongly depends on the ability of the species to cope with environmental stress. In NW Spain, commercial clam beds, which are usually co-occupied by the seagrass Zostera noltei, are often exposed to reduced salinity caused by intense rainfalls. Our goals were to evaluate the effects of low salinity events on both juvenile clams and Z. noltei, including their interactions. A mesocosm experiment was performed to simulate three salinity decreases (35–35, 25–10, and 20–5), and several indicators of clam and seagrass performance were measured after 3 and 6 days of exposure and again after a recovery period of 4 days. No differences were observed in the non-native clam Ruditapes philippinarum, while oxygen consumption, clearance rate and growth decreased significantly in the native clams R. decussatus and Venerupis corrugata in response to low salinity stress. Zostera noltei indicators did not vary in response to low salinity exposure, except the sucrose content, which decreased. Moreover, the seagrass buffered juvenile clams from salinity fluctuations in the short term, although the interactions were weak. The species-specific sensitivity to low salinity should be a major concern in future management plans for the shellfish beds in the context of climate change.