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221 Research products, page 1 of 23

  • European Marine Science
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  • Research software . 2023
    Open Access English
    Authors: 
    Hassell, David; Gregory, Jonathan; Bartholomew, Sadie L.;
    Publisher: Zenodo
    Project: EC | IS-ENES3 (824084), EC | Couplet (786427), EC | IS-ENES2 (312979), UKRI | Addressing the Grand Chal... (NE/R000727/1), EC | SEACHANGE (247220)

    {"references": ["Hassell, D., Gregory, J., Blower, J., Lawrence, B. N., and Taylor, K. E.: A data model of the Climate and Forecast metadata conventions (CF-1.6) with a software implementation (cf-python v2.1), Geosci. Model Dev., 10, 4619\u20134646, https://doi.org/10.5194/gmd-10-4619-2017, 2017.", "Hassell et al., (2020). cfdm: A Python reference implementation of the CF data model. Journal of Open Source Software, 5(54), 2717, https://doi.org/10.21105/joss.02717"]} A CF-compliant Earth Science data analysis library Version 3.14.0 is the first to use Dask.

  • Open Access English
    Authors: 
    Hassell, David; Bartholomew, Sadie L.;
    Publisher: Zenodo
    Project: EC | IS-ENES3 (824084), UKRI | Addressing the Grand Chal... (NE/R000727/1), EC | IS-ENES2 (312979), EC | Couplet (786427), EC | SEACHANGE (247220)

    A Python reference implementation of the CF data model.

  • Open Access English
    Authors: 
    Romero-Alvarez, Johana; Lupaşcu, Aurelia; Lowe, Douglas; Badia, Alba; Acher-Nicholls, Scott; Dorling, Steve R.; Reeves, Claire E.; Butler, Tim;
    Project: EC | ASIBIA (616938)

    Tropospheric ozone (O3) concentrations depend on a combination of hemispheric, regional, and local-scale processes. Estimates of how much O3 is produced locally vs. transported from further afield are essential in air quality management and regulatory policies. Here, a tagged-ozone mechanism within the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is used to quantify the contributions to surface O3 in the UK from anthropogenic nitrogen oxide (NOx) emissions from inside and outside the UK during May–August 2015. The contribution of the different source regions to three regulatory O3 metrics is also examined. It is shown that model simulations predict the concentration and spatial distribution of surface O3 with a domain-wide mean bias of −3.7 ppbv. Anthropogenic NOx emissions from the UK and Europe account for 13 % and 16 %, respectively, of the monthly mean surface O3 in the UK, as the majority (71 %) of O3 originates from the hemispheric background. Hemispheric O3 contributes the most to concentrations in the north and the west of the UK with peaks in May, whereas European and UK contributions are most significant in the east, south-east, and London, i.e. the UK's most populated areas, intensifying towards June and July. Moreover, O3 from European sources is generally transported to the UK rather than produced in situ. It is demonstrated that more stringent emission controls over continental Europe, particularly in western Europe, would be necessary to improve the health-related metric MDA8 O3 above 50 and 60 ppbv. Emission controls over larger areas, such as the Northern Hemisphere, are instead required to lessen the impacts on ecosystems as quantified by the AOT40 metric.

  • Open Access English
    Authors: 
    McLean, Dianne L.; Ferreira, Luciana C.; Benthuysen, Jessica A.; Miller, Karen J.; Schlappy, Marie-Lise; Ajemian, Matthew J.; Berry, Oliver; Birchenough, Silvana N. R.; Bond, Todd; Boschetti, Fabio; +36 more
    Country: United Kingdom

    This research was supported by the National Decommissioning Research Initiative (NDRI Australia). We acknowledge the time contribution of all co-authors and additionally via research undertaken through the UKRI INSITE Programme including projects ANChor, CHASANS (NE/T010886/1), EcoConnect, EcoSTAR (NE/T010614/1), FuECoMMS (NE/T010800/1), MAPS, NSERC. DMP was supported through The Marine Alliance for Science and Technology for Scotland (MASTS) funded by the Scottish Funding Council and contributing institutions. SNRB and KH (Cefas) were funded by Cefas and the UK INSITE North Sea programme. Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure. Publisher PDF Peer reviewed

  • Open Access English
    Authors: 
    Marwan, Norbert;
    Publisher: Zenodo
    Project: EC | MIONIÑO (796220), EC | EARTHSEQUENCING (617462), UKRI | Dynamics of the Oligocene... (NE/L007452/1), EC | TiPES (820970)

    The data file `CENOGRID_Loess_20.txt` contains the astronomically tuned deep-sea benthic foraminifer carbon (������C) and oxygen (�������O) isotope reference records uniformly covering the entire Cenozoic. The first column is the tuned age in Ma, the second column the ������C, and the third column the �������O record. The original calculations were performed using the CRP Toolbox for MATLAB. In order to avoid installing the toolbox and for better performance, the functions for calculating RP and RQA were here reimplemented, providing identical result. To reproduce the RPs in Fig. 2, use the script `perform_rp.m`, for reproducing the determinism values and upper confidence bounds, use the script `perform_rqa.m`. {"references": ["T. Westerhold, N. Marwan, et al: An astronomically dated record of Earth's climate and its predictability over the last 66 million years, Science, 369(6509), 1383\u20131387 (2020)"]}

  • Open Access English
    Authors: 
    Healy, Susan D.; Patton, B. Wren;
    Country: United Kingdom

    But fish cognitive ecology did not begin in rivers and streams. Rather, one of the starting points for work on fish cognitive ecology was work done on the use of visual cues by homing pigeons. Prior to working with fish, Victoria Braithwaite helped to establish that homing pigeons rely not just on magnetic and olfactory cues but also on visual cues for successful return to their home loft. Simple, elegant experiments on homing established Victoria's ability to develop experimental manipulations to examine the role of visual cues in navigation by fish in familiar areas. This work formed the basis of a rich seam of work whereby a fish's ecology was used to propose hypotheses and predictions as to preferred cue use, and then cognitive abilities in a variety of fish species, from model systems (Atlantic salmon and sticklebacks) to the Panamanian Brachyraphis episcopi. Cognitive ecology in fish led to substantial work on fish pain and welfare, but was never left behind, with some of Victoria's last work addressed to determining the neural instantiation of cognitive variation. Publisher PDF Peer reviewed

  • Open Access English
    Authors: 
    Iyer, Ram Balam;
    Publisher: eScholarship, University of California
    Country: United States

    Time and energy are finite resources in any environment, and how and when organisms use their available resources to survive and reproduce is the crux of life history theory (Gadgil and Bossert 1970; Balon 1975; Stearns 1976). The different survival strategies used by animals are often shaped by their environment in addition to their biology (Winemiller and Rose 1992), which allows for exploration into biological variability when environmental factors are known. For this reason, the Line Islands in the Central Pacific provide an ideal location to perform observational studies due to their unique productivity gradient and fish assemblage structures across the island chain (Sandin et al. 2008; DeMartini et al. 2008; Fox et al. 2018; Zgliczynski et al. 2019). Many of the world’s coral reefs are in remote regions that lack monitoring programs or even local populations, so conducting ecological surveys on fish communities in these regions can require extensive amounts of time, energy, resources and people. The inherent variability an environment exerts on the many factors that contribute to growth over a lifetime make it difficult to generate a directly proportional formula that calculates age. A novel age estimation method was developed that utilizes in-situ visual census data to estimate the age of fishes, and as a case study, several fish were chosen as representative species to explore its capabilities. Through this process, new ecological information and insight can be gained about the age structures of fish populations both between and throughout the Line Islands.

  • Open Access English
    Authors: 
    Labare, Michaela Faith;
    Publisher: eScholarship, University of California
    Country: United States

    Understanding fish diversity patterns is critical for fisheries management amidst overfishing and climate change. Fish egg surveys have been used to characterize pelagic spawning fish communities, estimate biomass, and track population trends in response to perturbations. Environmental DNA (eDNA) metabarcoding has been implemented to rapidly and non-invasively survey marine ecosystems. To understand the efficacy of eDNA metabarcoding for assessing pelagic spawning fish community composition, concurrent eDNA metabarcoding and fish egg DNA barcoding off Scripps Institution of Oceanography’s Pier (La Jolla, CA) were conducted. Both methods revealed seasonal patterns in agreement with previous fish and fish egg surveys. Species richness was highest in late spring and summer. The presence and spawning of commercially important species and species of conservation concern were detected. Both methods showed overlap for pelagic spawning fishes for broadcast spawners, schooling fish, and locally abundant species. Some actively spawning species were not co-detected with eDNA, likely due to different sampling strategies, taxonomic biases, and abiotic/biotic factors influencing eDNA transport, shedding, and degradation. We identified key advantages and disadvantages of each method. Fish egg barcoding provided information on spawning trends but did not detect taxa with alternate reproduction strategies. Metabarcoding eDNA detected species not found in fish egg sampling, including demersal and viviparous bony fishes, non-spawning adults, Chondrichthyan, and Mammalian species, but missed abundant pelagic fish eggs. This study demonstrates that DNA barcoding of fish eggs and eDNA metabarcoding work best in tandem as each method identified unique fish taxa and provided complementary ecological and biological insight.

  • Open Access English
    Authors: 
    Cohen, Rebecca Emily;
    Publisher: eScholarship, University of California
    Country: United States

    The western North Atlantic is a dynamic region characterized by the Gulf Stream western boundary current and inhabited by a diverse host of odontocete, or toothed whale, top predators. Their habitats are highly exploited by commercial fisheries, shipping, marine energy extraction, and naval exercises, subjecting them to a variety of potentially harmful interactions. Many of these species remain poorly understood due to the difficulties of observing them in the pelagic environment. Their habitat utilization and the impacts of anthropogenic activities are not well known. Over the past decade, passive acoustic data has become increasingly utilized for the study of a wide variety of marine animals, and offers several advantages over traditional line-transect visual survey methods. Passive acoustic devices can be deployed at offshore monitoring sites for long periods of time, enabling detection of even rare and cryptic species across seasons and sea states, and without altering animal behaviors. Here we utilized a large passive acoustic data set collected across a latitudinal habitat gradient in the western North Atlantic to address fundamental knowledge gaps in odontocete ecology. I approached the problem of discriminating between species based on spectral and temporal features of echolocation clicks by using machine learning to identify novel click types, and then matching these click types to species using spatiotemporal correlates. I was able to identify novel click types associated with short-beaked common dolphins, Risso’s dolphins, and short-finned pilot whales in this way. Next I characterized temporal patterns in presence and activity for ten different species across our monitoring sites at three different temporal scales: seasonal, lunar, and diel. I observed spatiotemporal separation of apparent competitors, and complex behavioral patterns modulated by interactions between the seasonal, lunar, and diel cycles. Finally I investigated the relationships between species presence and oceanographic covariates to predict habitat suitability across the region, and explored niche partitioning between potentially competitive species. The insights gained here significantly advance our understanding of toothed whale ecology in this region, and can be used for more effective population assessments and management in the face of anthropogenic threats and climate change.

  • Open Access English
    Authors: 
    Berta, Veronica Zsazsa;
    Publisher: eScholarship, University of California
    Country: United States

    Amines were measured by aerosol mass spectrometry (AMS) and Fourier Transform Infrared (FTIR) spectroscopy during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) cruises. Both AMS non-refractory (NR) amine ion fragments comprising the AMS CxHyNz family and FTIR non-volatile (NV) amine measured as primary (C-NH2) amine groups typically had greater concentrations in continental air masses than marine air masses. Secondary continental sources of AMS NR amine fragments were identified by consistent correlations to AMS NR nitrate, AMS NR m/z 44, IC non-sea salt potassium, and radon for most air masses. FTIR NV amine group mass concentrations for particles with diameters <1 μm showed large contributions from a primary marine source that was identified by significant correlations with measurements of wind speed, chlorophyll a, seawater dimethylsulfide (DMS), AMS NR chloride, and ion chromatography (IC) sea salt as well as FTIR NV alcohol groups in both marine and continental air masses. FTIR NV amine group mass concentrations in <0.18 μm and <0.5 μm particle samples in marine air masses likely have a biogenic secondary source associated with strong correlations to FTIR NV acid groups, which are not present for <1 μm particle samples. The average seasonal contribution of AMS NR amine fragments and FTIR NV amine groups ranged from 27% primary marine amine and 73% secondary continental amine during Early Spring to 53% primary amine and 47% secondary continental amine during Winter. These results demonstrate that AMS NR and FTIR NV amine measurements are complementary and can be used together to investigate the variety and sources of amines in the marine environment.

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.
221 Research products, page 1 of 23
  • Research software . 2023
    Open Access English
    Authors: 
    Hassell, David; Gregory, Jonathan; Bartholomew, Sadie L.;
    Publisher: Zenodo
    Project: EC | IS-ENES3 (824084), EC | Couplet (786427), EC | IS-ENES2 (312979), UKRI | Addressing the Grand Chal... (NE/R000727/1), EC | SEACHANGE (247220)

    {"references": ["Hassell, D., Gregory, J., Blower, J., Lawrence, B. N., and Taylor, K. E.: A data model of the Climate and Forecast metadata conventions (CF-1.6) with a software implementation (cf-python v2.1), Geosci. Model Dev., 10, 4619\u20134646, https://doi.org/10.5194/gmd-10-4619-2017, 2017.", "Hassell et al., (2020). cfdm: A Python reference implementation of the CF data model. Journal of Open Source Software, 5(54), 2717, https://doi.org/10.21105/joss.02717"]} A CF-compliant Earth Science data analysis library Version 3.14.0 is the first to use Dask.

  • Open Access English
    Authors: 
    Hassell, David; Bartholomew, Sadie L.;
    Publisher: Zenodo
    Project: EC | IS-ENES3 (824084), UKRI | Addressing the Grand Chal... (NE/R000727/1), EC | IS-ENES2 (312979), EC | Couplet (786427), EC | SEACHANGE (247220)

    A Python reference implementation of the CF data model.

  • Open Access English
    Authors: 
    Romero-Alvarez, Johana; Lupaşcu, Aurelia; Lowe, Douglas; Badia, Alba; Acher-Nicholls, Scott; Dorling, Steve R.; Reeves, Claire E.; Butler, Tim;
    Project: EC | ASIBIA (616938)

    Tropospheric ozone (O3) concentrations depend on a combination of hemispheric, regional, and local-scale processes. Estimates of how much O3 is produced locally vs. transported from further afield are essential in air quality management and regulatory policies. Here, a tagged-ozone mechanism within the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is used to quantify the contributions to surface O3 in the UK from anthropogenic nitrogen oxide (NOx) emissions from inside and outside the UK during May–August 2015. The contribution of the different source regions to three regulatory O3 metrics is also examined. It is shown that model simulations predict the concentration and spatial distribution of surface O3 with a domain-wide mean bias of −3.7 ppbv. Anthropogenic NOx emissions from the UK and Europe account for 13 % and 16 %, respectively, of the monthly mean surface O3 in the UK, as the majority (71 %) of O3 originates from the hemispheric background. Hemispheric O3 contributes the most to concentrations in the north and the west of the UK with peaks in May, whereas European and UK contributions are most significant in the east, south-east, and London, i.e. the UK's most populated areas, intensifying towards June and July. Moreover, O3 from European sources is generally transported to the UK rather than produced in situ. It is demonstrated that more stringent emission controls over continental Europe, particularly in western Europe, would be necessary to improve the health-related metric MDA8 O3 above 50 and 60 ppbv. Emission controls over larger areas, such as the Northern Hemisphere, are instead required to lessen the impacts on ecosystems as quantified by the AOT40 metric.

  • Open Access English
    Authors: 
    McLean, Dianne L.; Ferreira, Luciana C.; Benthuysen, Jessica A.; Miller, Karen J.; Schlappy, Marie-Lise; Ajemian, Matthew J.; Berry, Oliver; Birchenough, Silvana N. R.; Bond, Todd; Boschetti, Fabio; +36 more
    Country: United Kingdom

    This research was supported by the National Decommissioning Research Initiative (NDRI Australia). We acknowledge the time contribution of all co-authors and additionally via research undertaken through the UKRI INSITE Programme including projects ANChor, CHASANS (NE/T010886/1), EcoConnect, EcoSTAR (NE/T010614/1), FuECoMMS (NE/T010800/1), MAPS, NSERC. DMP was supported through The Marine Alliance for Science and Technology for Scotland (MASTS) funded by the Scottish Funding Council and contributing institutions. SNRB and KH (Cefas) were funded by Cefas and the UK INSITE North Sea programme. Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure. Publisher PDF Peer reviewed

  • Open Access English
    Authors: 
    Marwan, Norbert;
    Publisher: Zenodo
    Project: EC | MIONIÑO (796220), EC | EARTHSEQUENCING (617462), UKRI | Dynamics of the Oligocene... (NE/L007452/1), EC | TiPES (820970)

    The data file `CENOGRID_Loess_20.txt` contains the astronomically tuned deep-sea benthic foraminifer carbon (������C) and oxygen (�������O) isotope reference records uniformly covering the entire Cenozoic. The first column is the tuned age in Ma, the second column the ������C, and the third column the �������O record. The original calculations were performed using the CRP Toolbox for MATLAB. In order to avoid installing the toolbox and for better performance, the functions for calculating RP and RQA were here reimplemented, providing identical result. To reproduce the RPs in Fig. 2, use the script `perform_rp.m`, for reproducing the determinism values and upper confidence bounds, use the script `perform_rqa.m`. {"references": ["T. Westerhold, N. Marwan, et al: An astronomically dated record of Earth's climate and its predictability over the last 66 million years, Science, 369(6509), 1383\u20131387 (2020)"]}

  • Open Access English
    Authors: 
    Healy, Susan D.; Patton, B. Wren;
    Country: United Kingdom

    But fish cognitive ecology did not begin in rivers and streams. Rather, one of the starting points for work on fish cognitive ecology was work done on the use of visual cues by homing pigeons. Prior to working with fish, Victoria Braithwaite helped to establish that homing pigeons rely not just on magnetic and olfactory cues but also on visual cues for successful return to their home loft. Simple, elegant experiments on homing established Victoria's ability to develop experimental manipulations to examine the role of visual cues in navigation by fish in familiar areas. This work formed the basis of a rich seam of work whereby a fish's ecology was used to propose hypotheses and predictions as to preferred cue use, and then cognitive abilities in a variety of fish species, from model systems (Atlantic salmon and sticklebacks) to the Panamanian Brachyraphis episcopi. Cognitive ecology in fish led to substantial work on fish pain and welfare, but was never left behind, with some of Victoria's last work addressed to determining the neural instantiation of cognitive variation. Publisher PDF Peer reviewed

  • Open Access English
    Authors: 
    Iyer, Ram Balam;
    Publisher: eScholarship, University of California
    Country: United States

    Time and energy are finite resources in any environment, and how and when organisms use their available resources to survive and reproduce is the crux of life history theory (Gadgil and Bossert 1970; Balon 1975; Stearns 1976). The different survival strategies used by animals are often shaped by their environment in addition to their biology (Winemiller and Rose 1992), which allows for exploration into biological variability when environmental factors are known. For this reason, the Line Islands in the Central Pacific provide an ideal location to perform observational studies due to their unique productivity gradient and fish assemblage structures across the island chain (Sandin et al. 2008; DeMartini et al. 2008; Fox et al. 2018; Zgliczynski et al. 2019). Many of the world’s coral reefs are in remote regions that lack monitoring programs or even local populations, so conducting ecological surveys on fish communities in these regions can require extensive amounts of time, energy, resources and people. The inherent variability an environment exerts on the many factors that contribute to growth over a lifetime make it difficult to generate a directly proportional formula that calculates age. A novel age estimation method was developed that utilizes in-situ visual census data to estimate the age of fishes, and as a case study, several fish were chosen as representative species to explore its capabilities. Through this process, new ecological information and insight can be gained about the age structures of fish populations both between and throughout the Line Islands.

  • Open Access English
    Authors: 
    Labare, Michaela Faith;
    Publisher: eScholarship, University of California
    Country: United States

    Understanding fish diversity patterns is critical for fisheries management amidst overfishing and climate change. Fish egg surveys have been used to characterize pelagic spawning fish communities, estimate biomass, and track population trends in response to perturbations. Environmental DNA (eDNA) metabarcoding has been implemented to rapidly and non-invasively survey marine ecosystems. To understand the efficacy of eDNA metabarcoding for assessing pelagic spawning fish community composition, concurrent eDNA metabarcoding and fish egg DNA barcoding off Scripps Institution of Oceanography’s Pier (La Jolla, CA) were conducted. Both methods revealed seasonal patterns in agreement with previous fish and fish egg surveys. Species richness was highest in late spring and summer. The presence and spawning of commercially important species and species of conservation concern were detected. Both methods showed overlap for pelagic spawning fishes for broadcast spawners, schooling fish, and locally abundant species. Some actively spawning species were not co-detected with eDNA, likely due to different sampling strategies, taxonomic biases, and abiotic/biotic factors influencing eDNA transport, shedding, and degradation. We identified key advantages and disadvantages of each method. Fish egg barcoding provided information on spawning trends but did not detect taxa with alternate reproduction strategies. Metabarcoding eDNA detected species not found in fish egg sampling, including demersal and viviparous bony fishes, non-spawning adults, Chondrichthyan, and Mammalian species, but missed abundant pelagic fish eggs. This study demonstrates that DNA barcoding of fish eggs and eDNA metabarcoding work best in tandem as each method identified unique fish taxa and provided complementary ecological and biological insight.

  • Open Access English
    Authors: 
    Cohen, Rebecca Emily;
    Publisher: eScholarship, University of California
    Country: United States

    The western North Atlantic is a dynamic region characterized by the Gulf Stream western boundary current and inhabited by a diverse host of odontocete, or toothed whale, top predators. Their habitats are highly exploited by commercial fisheries, shipping, marine energy extraction, and naval exercises, subjecting them to a variety of potentially harmful interactions. Many of these species remain poorly understood due to the difficulties of observing them in the pelagic environment. Their habitat utilization and the impacts of anthropogenic activities are not well known. Over the past decade, passive acoustic data has become increasingly utilized for the study of a wide variety of marine animals, and offers several advantages over traditional line-transect visual survey methods. Passive acoustic devices can be deployed at offshore monitoring sites for long periods of time, enabling detection of even rare and cryptic species across seasons and sea states, and without altering animal behaviors. Here we utilized a large passive acoustic data set collected across a latitudinal habitat gradient in the western North Atlantic to address fundamental knowledge gaps in odontocete ecology. I approached the problem of discriminating between species based on spectral and temporal features of echolocation clicks by using machine learning to identify novel click types, and then matching these click types to species using spatiotemporal correlates. I was able to identify novel click types associated with short-beaked common dolphins, Risso’s dolphins, and short-finned pilot whales in this way. Next I characterized temporal patterns in presence and activity for ten different species across our monitoring sites at three different temporal scales: seasonal, lunar, and diel. I observed spatiotemporal separation of apparent competitors, and complex behavioral patterns modulated by interactions between the seasonal, lunar, and diel cycles. Finally I investigated the relationships between species presence and oceanographic covariates to predict habitat suitability across the region, and explored niche partitioning between potentially competitive species. The insights gained here significantly advance our understanding of toothed whale ecology in this region, and can be used for more effective population assessments and management in the face of anthropogenic threats and climate change.

  • Open Access English
    Authors: 
    Berta, Veronica Zsazsa;
    Publisher: eScholarship, University of California
    Country: United States

    Amines were measured by aerosol mass spectrometry (AMS) and Fourier Transform Infrared (FTIR) spectroscopy during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) cruises. Both AMS non-refractory (NR) amine ion fragments comprising the AMS CxHyNz family and FTIR non-volatile (NV) amine measured as primary (C-NH2) amine groups typically had greater concentrations in continental air masses than marine air masses. Secondary continental sources of AMS NR amine fragments were identified by consistent correlations to AMS NR nitrate, AMS NR m/z 44, IC non-sea salt potassium, and radon for most air masses. FTIR NV amine group mass concentrations for particles with diameters <1 μm showed large contributions from a primary marine source that was identified by significant correlations with measurements of wind speed, chlorophyll a, seawater dimethylsulfide (DMS), AMS NR chloride, and ion chromatography (IC) sea salt as well as FTIR NV alcohol groups in both marine and continental air masses. FTIR NV amine group mass concentrations in <0.18 μm and <0.5 μm particle samples in marine air masses likely have a biogenic secondary source associated with strong correlations to FTIR NV acid groups, which are not present for <1 μm particle samples. The average seasonal contribution of AMS NR amine fragments and FTIR NV amine groups ranged from 27% primary marine amine and 73% secondary continental amine during Early Spring to 53% primary amine and 47% secondary continental amine during Winter. These results demonstrate that AMS NR and FTIR NV amine measurements are complementary and can be used together to investigate the variety and sources of amines in the marine environment.