Advanced search in Research products
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
Include:
The following results are related to European Marine Science. Are you interested to view more results? Visit OpenAIRE - Explore.
65 Research products, page 1 of 7

  • European Marine Science
  • Other research products
  • 2013-2022
  • CA
  • KR

10
arrow_drop_down
Relevance
arrow_drop_down
  • Open Access English
    Authors: 
    Lucey, Noelle M; Lombardi, Chiara; Florio, Maurizio; DeMarchi, Lucia; Nannini, Matteo; Rundle, Simon; Gambi, Maria Cristina; Calosi, Piero;
    Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
    Project: NSERC

    Ocean acidification (OA) is likely to exert selective pressure on natural populations. Our ability to predict which marine species will adapt to OA, and what underlies this adaptive potential, are of high conservation and resource management priority. Using a naturally low pH vent site in the Mediterranean Sea (Castello Aragonese, Ischia) mirroring projected future OA conditions, we carried out a reciprocal transplant experiment to investigate the relative importance of phenotypic plasticity and local adaptation in two populations of the sessile, calcifying polychaete /Simplaria /sp. (Annelida, Serpulidae, Spirorbinae): one residing in low pH and the other from a nearby ambient (i.e. high) pH site. We measured a suite of fitness related traits (i.e. survival, reproductive output, maturation, population growth) and tube growth rates in laboratory-bred F2 generation individuals from both populations reciprocally transplanted back into both ambient and low pH /in situ/ habitats. Both populations showed lower expression in all traits, but increased tube growth rates, when exposed to low pH compared to high pH conditions, regardless of their site of origin suggesting that local adaptation to low pH conditions has not occurred. We also found comparable levels of plasticity in the two populations investigated, suggesting no influence of long-term exposure to low pH on the ability of populations to adjust their phenotype. Despite high variation in trait values among sites and the relatively extreme conditions at sites close to the vents (pH < 7.36), response trends were consistent across traits. Hence, our data suggest that, for /Simplaria /and possibly other calcifiers, neither local adaptations nor sufficient phenotypic plasticity levels appear to suffice in order to compensate for the negative impacts of OA on long-term survival. Our work also underlines the utility of field experiments in natural environments subjected to high level of /p/CO_2 for elucidating the potential for adaptation to future scenarios of OA. The first dataset includes data on the fitness traits assessed after the reciprocal transplant experiment, the second includes seawater (pH), temperature, and time of measurement, taken hourly at the low pH site (S2), during the reciprocal transplant experiment. The water parameters were taken hourly, from June 17, 2015 to July 6, 2015.

  • Open Access English
    Authors: 
    Morris, K. J.; Herrera, S.; Gubili, C.; Tyler, P. A.; Rogers, A.; Hauton, C.;
    Project: EC | HERMIONE (226354)

    Despite being an abundant group of significant ecological importance the phylogenetic relationships of the Octocorallia remain poorly understood and very much understudied. We used 1132 bp of two mitochondrial protein-coding genes, nad2 and mtMutS (previously referred to as msh1), to construct a phylogeny for 161 octocoral specimens from the Atlantic, including both Isididae and non-Isididae species. We found that four clades were supported using a concatenated alignment. Two of these (A and B) were in general agreement with the of Holaxonia–Alcyoniina and Anthomastus–Corallium clades identified by previous work. The third and fourth clades represent a split of the Calcaxonia–Pennatulacea clade resulting in a clade containing the Pennatulacea and a small number of Isididae specimens and a second clade containing the remaining Calcaxonia. When individual genes were considered nad2 largely agreed with previous work with MtMutS also producing a fourth clade corresponding to a split of Isididae species from the Calcaxonia–Pennatulacea clade. It is expected these difference are a consequence of the inclusion of Isisdae species that have undergone a gene inversion in the mtMutS gene causing their separation in the MtMutS only tree. The fourth clade in the concatenated tree is also suspected to be a result of this gene inversion, as there were very few Isidiae species included in previous work tree and thus this separation would not be clearly resolved. A~larger phylogeny including both Isididae and non Isididae species is required to further resolve these clades.

  • Open Access English
    Authors: 
    Tonin, Joseph;
    Country: Canada

    Over the past few decades, terrestrially derived dissolved organic carbon (DOC) has been recognized as a fundamental driver of food web productivity in nutrient poor lakes. The mechanisms that underlie these effects remain poorly understood, particularly for higher trophic levels including zooplankton, benthic invertebrates, and fish. In a survey of eight lakes in northwestern Ontario, I determined consumer biomass and used stable isotopes of carbon, nitrogen, and hydrogen to investigate relationships between DOC and pathways of energy flow, resource and habitat availability, and consumer biomass. Using Bayesian stable isotope mixing models, I found that hypolimnetic phytoplankton were an important resource for zooplankton in low-DOC lakes. With increased DOC concentrations, light attenuation increased and chlorophyll a concentrations below the thermocline were reduced relative to epilimnetic concentrations. At higher DOC concentrations, zooplankton acquired proportionately more energy from low quality terrestrial sources. Zooplankton biomass also declined with increasing utilization of terrestrial sources (allochthony), suggesting that terrestrial organic matter suppresses zooplankton productivity through simultaneous limitations on habitat and resource availability and quality. Based on biomass, the dominant fish species across my study lakes was White Sucker (Catostomus commersonnii). Bayesian mixing models indicated that allochthony by White Suckers increased with DOC and that greater allochthony was related to lower White Sucker biomass measured as catch-per-unit-effort (bCPUE). Both White Sucker bCPUE and chironomid biomass were positively related to mean light irradiance, with the highest biomasses of fish and chironomids occurring in lakes with a higher proportion of their volume in the photic zone. White Sucker bCPUE was strongly and positively correlated with chironomid biomass, suggesting that DOC-mediated resource limitation may influence fish productivity via reduced prey availability.

  • Open Access French
    Authors: 
    Guéveneux-Julien, Cynthia;
    Publisher: Université de Montréal
    Country: Canada

    Les écosystèmes aquatiques contiennent environ 25% de la biodiversité globale et sont parmi les plus affectés par l’activité humaine. Cela est entre autres causé par la position de « receveur » des rivières, lacs et océans dans leur bassin versant. Les espèces aquatiques, en eau douce particulièrement, sont ainsi hautement à risque d’être affectées par l’activité humaine. La protection de ces espèces peut inclure la protection et la restauration de leurs habitats. Les modèles de qualité d’habitats (MQH) peuvent être utilisés afin de déterminer quels habitats protéger et restaurer. Les MQH définissent la relation entre un indice de qualité d’habitats (IQH, e.g. densité) et des conditions environnementales. Toutefois, la performance des MQH dépend de l’IQH sélectionné. Ici, notre objectif est de comparer des MQH basés sur deux IQH estimés pour des poissons en rivière : 1) la densité instantanée, échantillonnée en transect par plongée en apnée et 2) la densité cumulative, échantillonnée en point fixe par caméra-vidéo en stéréo. Au total, douze modèles ont été construits et nos analyses indiquent que les MQH basés sur la densité instantanée ont des capacités explicatives significativement supérieures. Les variables environnementales retenues pour expliquer la distribution de chaque espèce sont toutefois différentes. Cela semble être causé en partie par des différences inhérentes à l’échantillonnage (e.g. échelle spatiale). Ces résultats démontrent que la densité instantanée en tant qu’IQH produit des MQH aux capacités explicatives supérieures et que les deux IQH semblent donner des informations complémentaires sur les caractéristiques des habitats à protéger et à restaurer. Aquatic ecosystems contain approximately 25% of the global biodiversity and are among the most affected by human activity. This may be caused by the position of “receivers” rivers, lakes and oceans have in their watershed. Aquatic species, specially in freshwater, are thus at high risk of being affected by human activity. Assuring the survival of these species may include protecting and restoring their habitats. Habitat quality models (HQM) can be used to determine which habitats to protect and how to restore damaged habitats. HQM are relationships between habitat quality indices (HQI, e.g., density) and environmental conditions prevailing in those habitats. However, how well an HQM performs depends on the chosen HQI it is computed with. For this research, we compared HQM based on two HQI estimated for fish in a river : 1) instantaneous density, sampled by transect snorkeling survey and 2) cumulative density, sampled by fixed stereo-video recording. Analyses of twelve HQM show that, contrary to our hypothesis, HQM based on instantaneous density had higher explanatory capacities. However, environmental conditions selected by both types of HQM to explain a species’ distribution were different. This may in part be explained by inherent differences of the sampling methods (e.g., spatial scale). We conclude that instantaneous density as HQI produces HQM of higher explanatory capacities, yet both HQI may provide complementary information on the characteristics of habitats to protect and restore.

  • Open Access English
    Authors: 
    Gustafsson, Erik; Hagens, Mathilde; Sun, Xiaole; Reed, Daniel C.; Humborg, Christoph; Slomp, Caroline P.; Gustafsson, Bo G.;
    Project: EC | PHOXY (278364), NWO | Response of the Iron Biog... (2300182111)

    Enhanced release of alkalinity from the seafloor, principally driven by anaerobic degradation of organic matter under low-oxygen conditions and associated secondary redox reactions, can increase the carbon dioxide (CO2) buffering capacity of seawater and therefore oceanic CO2 uptake. The Baltic Sea has undergone severe changes in oxygenation state and total alkalinity (TA) over the past decades. The link between these concurrent changes has not yet been investigated in detail. A recent system-wide TA budget constructed for the past 50 years using BALTSEM, a coupled physical–biogeochemical model for the whole Baltic Sea area revealed an unknown TA source. Here we use BALTSEM in combination with observational data and one-dimensional reactive-transport modeling of sedimentary processes in the Fårö Deep, a deep Baltic Sea basin, to test whether sulfate (SO42-) reduction coupled to iron (Fe) sulfide burial can explain the missing TA source in the Baltic Proper. We calculated that this burial can account for up to 26 % of the missing source in this basin, with the remaining TA possibly originating from unknown river inputs or submarine groundwater discharge. We also show that temporal variability in the input of Fe to the sediments since the 1970s drives changes in sulfur (S) burial in the Fårö Deep, suggesting that Fe availability is the ultimate limiting factor for TA generation under anoxic conditions. The implementation of projected climate change and two nutrient load scenarios for the 21st century in BALTSEM shows that reducing nutrient loads will improve deep water oxygen conditions, but at the expense of lower surface water TA concentrations, CO2 buffering capacities and faster acidification. When these changes additionally lead to a decrease in Fe inputs to the sediment of the deep basins, anaerobic TA generation will be reduced even further, thus exacerbating acidification. This work highlights that Fe dynamics plays a key role in the release of TA from sediments where Fe sulfide formation is limited by Fe availability, as exemplified by the Baltic Sea. Moreover, it demonstrates that burial of Fe sulfides should be included in TA budgets of low-oxygen basins.

  • Open Access English
    Authors: 
    Fletcher, Tamara L.; Warden, Lisa; Sinninghe Damsté, Jaap S.; Brown, Kendrick J.; Rybczynski, Natalia; Gosse, John C.; Ballantyne, Ashley P.;
    Project: NSF | Collaborative Research: A... (1418421), EC | PACEMAKER (226600), NSERC , NWO | Perturbations of System E... (2300181601)

    The mid-Pliocene is a valuable time interval for investigating equilibrium climate at current atmospheric CO2 concentrations because atmospheric CO2 concentrations are thought to have been comparable to the current day and yet the climate and distribution of ecosystems were quite different. One intriguing, but not fully understood, feature of the early to mid-Pliocene climate is the amplified Arctic temperature response and its impact on Arctic ecosystems. Only the most recent models appear to correctly estimate the degree of warming in the Pliocene Arctic and validation of the currently proposed feedbacks is limited by scarce terrestrial records of climate and environment. Here we reconstruct the summer temperature and fire regime from a subfossil fen-peat deposit on west–central Ellesmere Island, Canada, that has been chronologically constrained using cosmogenic nuclide burial dating to 3.9+1.5/-0.5 Ma. The estimate for average mean summer temperature is 15.4±0.8 ∘C using specific bacterial membrane lipids, i.e., branched glycerol dialkyl glycerol tetraethers. This is above the proposed threshold that predicts a substantial increase in wildfire in the modern high latitudes. Macro-charcoal was present in all samples from this Pliocene section with notably higher charcoal concentration in the upper part of the sequence. This change in charcoal was synchronous with a change in vegetation that included an increase in abundance of fire-promoting Pinus and Picea. Paleo-vegetation reconstructions are consistent with warm summer temperatures, relatively low summer precipitation and an incidence of fire comparable to fire-adapted boreal forests of North America and central Siberia. To our knowledge, this site provides the northernmost evidence of fire during the Pliocene. It suggests that ecosystem productivity was greater than in the present day, providing fuel for wildfires, and that the climate was conducive to the ignition of fire during this period. The results reveal that interactions between paleo-vegetation and paleoclimate were mediated by fire in the High Arctic during the Pliocene, even though CO2 concentrations were similar to modern values.

  • Other research product . Other ORP type . 2021
    Open Access English
    Authors: 
    Bailey, Neal;
    Country: Canada

    Mercury is a potent toxicant whose concentration in the environment has increased markedly due to human activity. However, uncertainties exist on sources and sinks of mercury, including those associated with mineral dust, with the Sahara Desert being the largest aeolian dust source worldwide. To characterize mercury associated with Saharan dust export to the Atlantic Ocean, aeolian dust (>2.2 µm in size) and soil samples were collected from the Canary Islands and Cabo Verde, ~400 and 800 km off the west coast of Africa. The sources of the dust samples were determined by back-trajectory analysis, and mercury content was characterized via direct mercury analysis. Mercury concentrations differed significantly (p 70%) over the Atlantic Ocean, had a mean mercury concentration of 29.8±31.3 ng/g (w/w), or 1.40±1.34 pg/m3 (w/v); this result is in the lower end of the data reported for remote coastal locations on a w/v basis, but lower than any on a w/w basis. Saharan-origin dust, defined as dust with a back trajectory predominantly (>70%) over the Sahara Desert, had a higher mean mercury concentration of 72.8±7.43 ng/g, or 4.64±2.15 pg/m3. Concentrations of mercury in dust samples were found to increase as back trajectories passed over a larger extent of the western African land surface relative to the Atlantic Ocean water surface. Finally, particulate-bound mercury (PBM) concentrations measured at Cabo Verde were used to estimate the flux of particulate mercury to major dust-impacted regions of the Atlantic Ocean, an area comprising 21.3 million km2. The PBM flux to this region is estimated at 6.5±2.2 t/y if all dust originates from the Sahara, or 3.6±1.6 t/y if the dust is of mixed Saharan and Atlantic origins. These numbers represent only ~1% to 3% of the total mercury deposition to the region estimated by current global mercury models. Surface soil mercury concentrations measured in the Canary Islands further support minimal mercury inputs from Saharan dust. Our study thus suggests the current models may have considerably overestimated Saharan dust contribution to mercury deposition.

  • Restricted English
    Authors: 
    Rook, Natalie;
    Country: Canada

    The decline of species is a prominent issue that Canada is trying to mitigate through the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and the Species at Risk Act (SARA). One of the organisms currently listed under SARA is the Grass Pickerel (Esox americanus vermiculatus) due to population declines since the 1970’s. Grass Pickerel are found in the St. Lawrence River, but it is not a core habitat for the fish so there is little known about this population. Fish sampling occurred from 1989 to 1995 and 2005 to 2012 in the St. Lawrence River. The purpose of the study was to document young of the year (YOY) Muskellunge habitat. However, during the sampling Grass Pickerel were caught as well, which forms the basis of this study. Through statistical analysis the stability of the Grass Pickerel population was determined as well as habitat requirements and how other fish species impact Grass Pickerel. In spite of the small numbers caught, the population size has stayed consistent among the two time frames even though there were some changes to the environment such as the invasion of Round Goby. Habitat characteristics commonly associated with Grass Pickerel were submergent vegetation and muck substrate. This was most likely because Grass Pickerel use vegetation for spawning, stalking prey and protection. There was little relationship between Grass Pickerel and temperature as they are a warmwater fish species so despite an increase in temperature it was still in their optimal range. Grass Pickerel were rarely found with Northern Pike and there was a negative relation between the two species abundance, which was most likely caused by predatory interactions.

  • Open Access English
    Authors: 
    Lowles, Andrew;
    Country: Canada

    Environmental and physical conditions are considered primary drivers of fish community assemblages. The anthropogenic alteration of aquatic ecosystems is implicated as a primary threat to fisheries worldwide. In riverine ecosystems, river-wide barriers may alter natural fluvial processes and hinder fish movement through the system. In this study, I use data collected from two successive years (2008 and 2009) of intensive quantitative electrofishing Casselman and Marcogliese (2008, 2009) performed in different seasons (late fall and late summer) on the lower Ottawa and Mississippi River systems, Ontario, to investigate the effects of sampling season, distance from the river mouth, water temperature, conductivity, rank of velocity and dams on fish abundance, species richness and the Shannon-Weiner Index (SWI) as a measure of species diversity. Sampling in late summer, compared with late fall, resulted in greater species richness and diversity. Colder water temperature affected community composition, and species richness decreased upstream, while diversity did not change. In both seasons, the distance from the river mouth influenced fish community composition, whereas dams appeared to have no effect. This suggests that the continuous gradient model of the River Continuum Concept (RCC) would be applicable in these fragmented systems, which are not heavily altered by fractionation. To effectively manage cost and accuracy when collecting fish community data in large rivers, it is essential to sample strategically during seasons likely to maximize diversity and richness. Sampling intensively during warm water months in various river reaches would likely provide the most complete representation of fish assemblage.

  • Closed Access English
    Authors: 
    Bose, Aneesh;
    Country: Canada