Pub Date : 2023-01-01DOI: 10.1525/elementa.2023.00052
Zongbo Shi, Sonja Endres, Anna Rutgersson, Shams Al-Hajjaji, Selma Brynolf, Dennis Booge, Ida-Maja Hassellöv, Christos Kontovas, Rohan Kumar, Huan Liu, Christa Marandino, Volker Matthias, Jana Moldanová, Kent Salo, Maxim Sebe, Wen Yi, Mingxi Yang, Chao Zhang
Shipping is the cornerstone of international trade and thus a critical economic sector. However, ships predominantly use fossil fuels for propulsion and electricity generation, which emit greenhouse gases such as carbon dioxide and methane, and air pollutants such as particulate matter, sulfur oxides, nitrogen oxides, and volatile organic compounds. The availability of Automatic Information System (AIS) data has helped to improve the emission inventories of air pollutants from ship stacks. Recent laboratory, shipborne, satellite and modeling studies provided convincing evidence that ship-emitted air pollutants have significant impacts on atmospheric chemistry, clouds, and ocean biogeochemistry. The need to improve air quality to protect human health and to mitigate climate change has driven a series of regulations at international, national, and local levels, leading to rapid energy and technology transitions. This resulted in major changes in air emissions from shipping with implications on their environmental impacts, but observational studies remain limited. Growth in shipping in polar areas is expected to have distinct impacts on these pristine and sensitive environments. The transition to more sustainable shipping is also expected to cause further changes in fuels and technologies, and thus in air emissions. However, major uncertainties remain on how future shipping emissions may affect atmospheric composition, clouds, climate, and ocean biogeochemistry, under the rapidly changing policy (e.g., targeting decarbonization), socioeconomic, and climate contexts.
{"title":"Perspectives on shipping emissions and their impacts on the surface ocean and lower atmosphere: An environmental-social-economic dimension","authors":"Zongbo Shi, Sonja Endres, Anna Rutgersson, Shams Al-Hajjaji, Selma Brynolf, Dennis Booge, Ida-Maja Hassellöv, Christos Kontovas, Rohan Kumar, Huan Liu, Christa Marandino, Volker Matthias, Jana Moldanová, Kent Salo, Maxim Sebe, Wen Yi, Mingxi Yang, Chao Zhang","doi":"10.1525/elementa.2023.00052","DOIUrl":"https://doi.org/10.1525/elementa.2023.00052","url":null,"abstract":"Shipping is the cornerstone of international trade and thus a critical economic sector. However, ships predominantly use fossil fuels for propulsion and electricity generation, which emit greenhouse gases such as carbon dioxide and methane, and air pollutants such as particulate matter, sulfur oxides, nitrogen oxides, and volatile organic compounds. The availability of Automatic Information System (AIS) data has helped to improve the emission inventories of air pollutants from ship stacks. Recent laboratory, shipborne, satellite and modeling studies provided convincing evidence that ship-emitted air pollutants have significant impacts on atmospheric chemistry, clouds, and ocean biogeochemistry. The need to improve air quality to protect human health and to mitigate climate change has driven a series of regulations at international, national, and local levels, leading to rapid energy and technology transitions. This resulted in major changes in air emissions from shipping with implications on their environmental impacts, but observational studies remain limited. Growth in shipping in polar areas is expected to have distinct impacts on these pristine and sensitive environments. The transition to more sustainable shipping is also expected to cause further changes in fuels and technologies, and thus in air emissions. However, major uncertainties remain on how future shipping emissions may affect atmospheric composition, clouds, climate, and ocean biogeochemistry, under the rapidly changing policy (e.g., targeting decarbonization), socioeconomic, and climate contexts.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135058862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2020.00080
J. Laliberté, E. Rehm, B. Hamre, C. Goyens, D. Perovich, M. Babin
Deriving sea ice albedo from spaceborne platforms is of interest to model the propagation of the photosynthetically available radiation (PAR) through Arctic sea ice. We show here that use of the Moderate Resolution Imaging Spectroradiometer (MODIS) operational surface reflectance satellite product to derive albedo in the PAR spectral range is possible. To retrieve PAR albedo from the remote sensing surface reflectance, we trained a predictive model based on a principal component analysis with in situ and simulated data. The predictive model can be applied to first-year sea ice surfaces such as dry snow, melting snow, bare ice and melt ponds. Based on in situ measurements and the prescribed atmospheric correction uncertainty, the estimated PAR albedo had a mean absolute error of 0.057, a root mean square error of 0.074 and an R2 value of 0.91. As a demonstration, we retrieved PAR albedo on a 9-km2 area over late spring and early summer 2015 and 2016 at a coastal location in Baffin Bay, Canada. On-site measurements of PAR albedo, melt pond fraction and types of precipitation were used to examine the estimated PAR albedo time series. The results show a dynamic and realistic PAR albedo time series, although clouds remained the major obstacle to the method. This easy-to-implement model may be used for the partitioning of PAR in the Arctic Ocean and ultimately to better understand the dynamics of marine primary producers.
{"title":"A method to derive satellite PAR albedo time series over first-year sea ice in the Arctic Ocean","authors":"J. Laliberté, E. Rehm, B. Hamre, C. Goyens, D. Perovich, M. Babin","doi":"10.1525/elementa.2020.00080","DOIUrl":"https://doi.org/10.1525/elementa.2020.00080","url":null,"abstract":"Deriving sea ice albedo from spaceborne platforms is of interest to model the propagation of the photosynthetically available radiation (PAR) through Arctic sea ice. We show here that use of the Moderate Resolution Imaging Spectroradiometer (MODIS) operational surface reflectance satellite product to derive albedo in the PAR spectral range is possible. To retrieve PAR albedo from the remote sensing surface reflectance, we trained a predictive model based on a principal component analysis with in situ and simulated data. The predictive model can be applied to first-year sea ice surfaces such as dry snow, melting snow, bare ice and melt ponds. Based on in situ measurements and the prescribed atmospheric correction uncertainty, the estimated PAR albedo had a mean absolute error of 0.057, a root mean square error of 0.074 and an R2 value of 0.91. As a demonstration, we retrieved PAR albedo on a 9-km2 area over late spring and early summer 2015 and 2016 at a coastal location in Baffin Bay, Canada. On-site measurements of PAR albedo, melt pond fraction and types of precipitation were used to examine the estimated PAR albedo time series. The results show a dynamic and realistic PAR albedo time series, although clouds remained the major obstacle to the method. This easy-to-implement model may be used for the partitioning of PAR in the Arctic Ocean and ultimately to better understand the dynamics of marine primary producers.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66938583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.000116
M. Smith, Luisa von Albedyll, Ian A. Raphael, B. Lange, I. Matero, E. Salganik, M. Webster, M. Granskog, A. Fong, R. Lei, B. Light
During the Arctic melt season, relatively fresh meltwater layers can accumulate under sea ice as a result of snow and ice melt, far from terrestrial freshwater inputs. Such under-ice meltwater layers, sometimes referred to as under-ice melt ponds, have been suggested to play a role in the summer sea ice mass balance both by isolating the sea ice from saltier water below, and by driving formation of ‘false bottoms’ below the sea ice. Such layers form at the interface of the fresher under-ice layer and the colder, saltier seawater below. During the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) expedition in the Central Arctic, we observed the presence of under-ice meltwater layers and false bottoms throughout July 2020 at primarily first-year ice locations. Here, we examine the distribution, prevalence, and drivers of under-ice ponds and the resulting false bottoms during this period. The average thickness of observed false bottoms and freshwater equivalent of under-ice meltwater layers was 0.08 m, with false bottom ice comprised of 74–87% FYI melt and 13–26% snow melt. Additionally, we explore these results using a 1D model to understand the role of dynamic influences on decoupling the ice from the seawater below. The model comparison suggests that the ice-ocean friction velocity was likely exceptionally low, with implications for air-ice-ocean momentum transfer. Overall, the prevalence of false bottoms was similar to or higher than noted during other observational campaigns, indicating that these features may in fact be common in the Arctic during the melt season. These results have implications for the broader ice-ocean system, as under-ice meltwater layers and false bottoms provide a source of ice growth during the melt season, potentially reduce fluxes between the ice and the ocean, isolate sea ice primary producers from pelagic nutrient sources, and may alter light transmission to the ocean below.
{"title":"Quantifying false bottoms and under-ice meltwater layers beneath Arctic summer sea ice with fine-scale observations","authors":"M. Smith, Luisa von Albedyll, Ian A. Raphael, B. Lange, I. Matero, E. Salganik, M. Webster, M. Granskog, A. Fong, R. Lei, B. Light","doi":"10.1525/elementa.2021.000116","DOIUrl":"https://doi.org/10.1525/elementa.2021.000116","url":null,"abstract":"During the Arctic melt season, relatively fresh meltwater layers can accumulate under sea ice as a result of snow and ice melt, far from terrestrial freshwater inputs. Such under-ice meltwater layers, sometimes referred to as under-ice melt ponds, have been suggested to play a role in the summer sea ice mass balance both by isolating the sea ice from saltier water below, and by driving formation of ‘false bottoms’ below the sea ice. Such layers form at the interface of the fresher under-ice layer and the colder, saltier seawater below. During the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) expedition in the Central Arctic, we observed the presence of under-ice meltwater layers and false bottoms throughout July 2020 at primarily first-year ice locations. Here, we examine the distribution, prevalence, and drivers of under-ice ponds and the resulting false bottoms during this period. The average thickness of observed false bottoms and freshwater equivalent of under-ice meltwater layers was 0.08 m, with false bottom ice comprised of 74–87% FYI melt and 13–26% snow melt. Additionally, we explore these results using a 1D model to understand the role of dynamic influences on decoupling the ice from the seawater below. The model comparison suggests that the ice-ocean friction velocity was likely exceptionally low, with implications for air-ice-ocean momentum transfer. Overall, the prevalence of false bottoms was similar to or higher than noted during other observational campaigns, indicating that these features may in fact be common in the Arctic during the melt season. These results have implications for the broader ice-ocean system, as under-ice meltwater layers and false bottoms provide a source of ice growth during the melt season, potentially reduce fluxes between the ice and the ocean, isolate sea ice primary producers from pelagic nutrient sources, and may alter light transmission to the ocean below.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66940448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00018
Vinícius Amaral, P. Lam, O. Marchal, M. Roca-Martí, James Fox, N. Nelson
Particle cycling rates in marine systems are difficult to measure directly, but of great interest in understanding how carbon and other elements are distributed throughout the ocean. Here, rates of particle production, aggregation, disaggregation, sinking, remineralization, and transport mediated by zooplankton diel vertical migration were estimated from size-fractionated measurements of particulate organic carbon (POC) concentration collected during the NASA EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) cruise at Station P in summer 2018. POC data were combined with a particle cycling model using an inverse method. Our estimates of the total POC settling flux throughout the water column are consistent with those derived from thorium-234 disequilibrium and sediment traps. A budget for POC in two size fractions, small (1–51 µm) and large (> 51 µm), was produced for both the euphotic zone (0–100 m) and the upper mesopelagic zone (100–500 m). We estimated that POC export at the base of the euphotic zone was 2.2 ± 0.8 mmol m−2 d−1, and that both small and large particles contributed considerably to the total export flux along the water column. The model results indicated that throughout the upper 500 m, remineralization leads to a larger loss of small POC than does aggregation, whereas disaggregation results in a larger loss of large POC than does remineralization. Of the processes explicitly represented in the model, zooplankton diel vertical migration is a larger source of large POC to the upper mesopelagic zone than the convergence of large POC due to particle sinking. Positive model residuals reveal an even larger unidentified source of large POC in the upper mesopelagic zone. Overall, our posterior estimates of particle cycling rate constants do not deviate much from values reported in the literature, i.e., size-fractionated POC concentration data collected at Station P are largely consistent with prior estimates given their uncertainties. Our budget estimates should provide a useful framework for the interpretation of process-specific observations obtained by various research groups in EXPORTS. Applying our inverse method to other systems could provide insight into how different biogeochemical processes affect the cycling of POC in the upper water column.
{"title":"Particle cycling rates at Station P as estimated from the inversion of POC concentration data","authors":"Vinícius Amaral, P. Lam, O. Marchal, M. Roca-Martí, James Fox, N. Nelson","doi":"10.1525/elementa.2021.00018","DOIUrl":"https://doi.org/10.1525/elementa.2021.00018","url":null,"abstract":"Particle cycling rates in marine systems are difficult to measure directly, but of great interest in understanding how carbon and other elements are distributed throughout the ocean. Here, rates of particle production, aggregation, disaggregation, sinking, remineralization, and transport mediated by zooplankton diel vertical migration were estimated from size-fractionated measurements of particulate organic carbon (POC) concentration collected during the NASA EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) cruise at Station P in summer 2018. POC data were combined with a particle cycling model using an inverse method. Our estimates of the total POC settling flux throughout the water column are consistent with those derived from thorium-234 disequilibrium and sediment traps. A budget for POC in two size fractions, small (1–51 µm) and large (> 51 µm), was produced for both the euphotic zone (0–100 m) and the upper mesopelagic zone (100–500 m). We estimated that POC export at the base of the euphotic zone was 2.2 ± 0.8 mmol m−2 d−1, and that both small and large particles contributed considerably to the total export flux along the water column. The model results indicated that throughout the upper 500 m, remineralization leads to a larger loss of small POC than does aggregation, whereas disaggregation results in a larger loss of large POC than does remineralization. Of the processes explicitly represented in the model, zooplankton diel vertical migration is a larger source of large POC to the upper mesopelagic zone than the convergence of large POC due to particle sinking. Positive model residuals reveal an even larger unidentified source of large POC in the upper mesopelagic zone. Overall, our posterior estimates of particle cycling rate constants do not deviate much from values reported in the literature, i.e., size-fractionated POC concentration data collected at Station P are largely consistent with prior estimates given their uncertainties. Our budget estimates should provide a useful framework for the interpretation of process-specific observations obtained by various research groups in EXPORTS. Applying our inverse method to other systems could provide insight into how different biogeochemical processes affect the cycling of POC in the upper water column.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66940557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.000063
Shahid Uz Zaman, Md. Riad Sarkar Pavel, Rumana Islam Rani, F. Jeba, Md. Safiqul Islam, Md Firoz Khan, Ross Edwards, A. Salam
Atmospheric aerosols affect human health, alter cloud optical properties, influence the climate and radiative balance, and contribute to the cooling of the atmosphere. Aerosol climatology based on aerosol robotic network (AERONET) and ozone monitoring instrument (OMI) data from two locations (Urban Dhaka and coastal Bhola Island) over Bangladesh was conducted for 8 years (2012–2019), focusing on two characterization schemes. Four aerosol parameters, such as extinction angstrom exponent (EAE), absorption AE (AAE), single scattering albedo (SSA), and real refractive index (RRI), were exclusively discussed to determine the types of aerosol. In addition, the light absorption properties of aerosol were inspected tagging the association between size parameters similar to fine mode fraction (FMF), AE, and absorption parameters (SSA and AAE). Results of aerosol absorption optical depth (AAOD) were validated with the satellite-borne cloud–aerosol lidar and infrared pathfinder satellite observation (CALIPSO) aerosol subtype profiles. The overall average values of AAOD for Dhaka and Bhola were (0.110 ± 0.002) [0.106, 0.114] and (0.075 ± 0.001) [0.073, 0.078], respectively. The values derived by OMI were the similar (0.024 ± 0.001 [0.023, 0.025] for Dhaka, and 0.023 ± 0.001 [0.023, 0.024] for Bhola). Two types of aerosols were potentially identified, for example, biomass burning and urban/industrial types over Bangladesh with insignificant contribution from the dust aerosol. Black carbon (BC) was the prominent absorbing aerosol (45.9%–89.1%) in all seasons with negligible contributions from mixed BC and/or dust and dust alone. Correlations between FMF and SSA confirmed that BC was the dominant aerosol type over Dhaka and Bhola. CALIPSO’s vertical information was consistent with the AERONET column information. The results of aerosol parameters will have a substantial impact on the aerosol radiative forcing, and climate modeling as well as air quality management in Southeast Asia’s heavily polluted territories.
{"title":"Aerosol climatology characterization over Bangladesh using ground-based and remotely sensed satellite measurements","authors":"Shahid Uz Zaman, Md. Riad Sarkar Pavel, Rumana Islam Rani, F. Jeba, Md. Safiqul Islam, Md Firoz Khan, Ross Edwards, A. Salam","doi":"10.1525/elementa.2021.000063","DOIUrl":"https://doi.org/10.1525/elementa.2021.000063","url":null,"abstract":"Atmospheric aerosols affect human health, alter cloud optical properties, influence the climate and radiative balance, and contribute to the cooling of the atmosphere. Aerosol climatology based on aerosol robotic network (AERONET) and ozone monitoring instrument (OMI) data from two locations (Urban Dhaka and coastal Bhola Island) over Bangladesh was conducted for 8 years (2012–2019), focusing on two characterization schemes. Four aerosol parameters, such as extinction angstrom exponent (EAE), absorption AE (AAE), single scattering albedo (SSA), and real refractive index (RRI), were exclusively discussed to determine the types of aerosol. In addition, the light absorption properties of aerosol were inspected tagging the association between size parameters similar to fine mode fraction (FMF), AE, and absorption parameters (SSA and AAE). Results of aerosol absorption optical depth (AAOD) were validated with the satellite-borne cloud–aerosol lidar and infrared pathfinder satellite observation (CALIPSO) aerosol subtype profiles. The overall average values of AAOD for Dhaka and Bhola were (0.110 ± 0.002) [0.106, 0.114] and (0.075 ± 0.001) [0.073, 0.078], respectively. The values derived by OMI were the similar (0.024 ± 0.001 [0.023, 0.025] for Dhaka, and 0.023 ± 0.001 [0.023, 0.024] for Bhola). Two types of aerosols were potentially identified, for example, biomass burning and urban/industrial types over Bangladesh with insignificant contribution from the dust aerosol. Black carbon (BC) was the prominent absorbing aerosol (45.9%–89.1%) in all seasons with negligible contributions from mixed BC and/or dust and dust alone. Correlations between FMF and SSA confirmed that BC was the dominant aerosol type over Dhaka and Bhola. CALIPSO’s vertical information was consistent with the AERONET column information. The results of aerosol parameters will have a substantial impact on the aerosol radiative forcing, and climate modeling as well as air quality management in Southeast Asia’s heavily polluted territories.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66940708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00055
S. Gonzalez, J. Horne, S. Danielson, Lilian Lieber, Guzmán López
The use of stationary, active acoustics provides an effective approach to characterize and monitor temporal variability in the abundance and behavior of pelagic organisms, especially in seasonally ice-covered waters of high latitude marine ecosystems. However, point measurements from stationary echosounders are limited in their spatial coverage. A quantification of the spatial area represented by point measurements (i.e., representative range) is required to ensure effective biological characterization and monitoring. Here, concurrent mobile and stationary active acoustic data collected during summers of 2015 and 2017 are used to assess the representative range of fish and zooplankton density measurements from the Chukchi Ecosystem Observatory located at Hanna Shoal, Northeast Chukchi Sea. Six methods used to calculate representative ranges of backscatter means and variances resulted in representative ranges between approximately 0.3 and 86 km, depending on the year and calculation method. Such relatively large representative ranges reflect the tight bio-physical associations and large characteristic environmental length scales of the NE Chukchi Sea. Between years, up to 10-fold variations in representative ranges were attributed to interannual changes in water mass characteristics and associated species assemblages. Differences of 1–2 orders of magnitude in our calculated ranges among methods are attributed to differences in the rationale and associated assumptions of each approach. The choice of method and resulting representative range depends on monitoring goals: detection of change, mapping of spatial distributions, characterization of spatial variance, or interpolation of temporal variability over space. Our comparison of stationary acoustic to mobile surveys extends the understanding of spatiotemporal variability of marine organism distributions in the NE Chukchi Sea and informs cost-effective design of observing systems to monitor and predict impacts of environmental change.
{"title":"Representative range of acoustic point source measurements in the Chukchi Sea","authors":"S. Gonzalez, J. Horne, S. Danielson, Lilian Lieber, Guzmán López","doi":"10.1525/elementa.2021.00055","DOIUrl":"https://doi.org/10.1525/elementa.2021.00055","url":null,"abstract":"The use of stationary, active acoustics provides an effective approach to characterize and monitor temporal variability in the abundance and behavior of pelagic organisms, especially in seasonally ice-covered waters of high latitude marine ecosystems. However, point measurements from stationary echosounders are limited in their spatial coverage. A quantification of the spatial area represented by point measurements (i.e., representative range) is required to ensure effective biological characterization and monitoring. Here, concurrent mobile and stationary active acoustic data collected during summers of 2015 and 2017 are used to assess the representative range of fish and zooplankton density measurements from the Chukchi Ecosystem Observatory located at Hanna Shoal, Northeast Chukchi Sea. Six methods used to calculate representative ranges of backscatter means and variances resulted in representative ranges between approximately 0.3 and 86 km, depending on the year and calculation method. Such relatively large representative ranges reflect the tight bio-physical associations and large characteristic environmental length scales of the NE Chukchi Sea. Between years, up to 10-fold variations in representative ranges were attributed to interannual changes in water mass characteristics and associated species assemblages. Differences of 1–2 orders of magnitude in our calculated ranges among methods are attributed to differences in the rationale and associated assumptions of each approach. The choice of method and resulting representative range depends on monitoring goals: detection of change, mapping of spatial distributions, characterization of spatial variance, or interpolation of temporal variability over space. Our comparison of stationary acoustic to mobile surveys extends the understanding of spatiotemporal variability of marine organism distributions in the NE Chukchi Sea and informs cost-effective design of observing systems to monitor and predict impacts of environmental change.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66941261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00050
C. Paton‐Walsh, K. Emmerson, R. Garland, M. Keywood, J. Hoelzemann, N. Huneeus, R. Buchholz, R. Humphries, K. Altieri, J. Schmale, Steven R. Wilson, C. Labuschagne, Egide Kalisa, J. Fisher, N. Deutscher, P. V. van Zyl, J. Beukes, W. Joubert, Lynwill G. Martin, T. Mkololo, C. Barbosa, M. de Fátima Andrade, R. Schofield, M. Mallet, M. Harvey, P. Formenti, S. Piketh, G. Olivares
This commentary paper from the recently formed International Global Atmospheric Chemistry (IGAC) Southern Hemisphere Working Group outlines key issues in atmospheric composition research that particularly impact the Southern Hemisphere. In this article, we present a broad overview of many of the challenges for understanding atmospheric chemistry in the Southern Hemisphere, before focusing in on the most significant factors that differentiate it from the Northern Hemisphere. We present sections on the importance of biogenic emissions and fires in the Southern Hemisphere, showing that these emissions often dominate over anthropogenic emissions in many regions. We then describe how these and other factors influence air quality in different parts of the Southern Hemisphere. Finally, we describe the key role of the Southern Ocean in influencing atmospheric chemistry and conclude with a description of the aims and scope of the newly formed IGAC Southern Hemisphere Working Group.
{"title":"Key challenges for tropospheric chemistry in the Southern Hemisphere","authors":"C. Paton‐Walsh, K. Emmerson, R. Garland, M. Keywood, J. Hoelzemann, N. Huneeus, R. Buchholz, R. Humphries, K. Altieri, J. Schmale, Steven R. Wilson, C. Labuschagne, Egide Kalisa, J. Fisher, N. Deutscher, P. V. van Zyl, J. Beukes, W. Joubert, Lynwill G. Martin, T. Mkololo, C. Barbosa, M. de Fátima Andrade, R. Schofield, M. Mallet, M. Harvey, P. Formenti, S. Piketh, G. Olivares","doi":"10.1525/elementa.2021.00050","DOIUrl":"https://doi.org/10.1525/elementa.2021.00050","url":null,"abstract":"This commentary paper from the recently formed International Global Atmospheric Chemistry (IGAC) Southern Hemisphere Working Group outlines key issues in atmospheric composition research that particularly impact the Southern Hemisphere. In this article, we present a broad overview of many of the challenges for understanding atmospheric chemistry in the Southern Hemisphere, before focusing in on the most significant factors that differentiate it from the Northern Hemisphere. We present sections on the importance of biogenic emissions and fires in the Southern Hemisphere, showing that these emissions often dominate over anthropogenic emissions in many regions. We then describe how these and other factors influence air quality in different parts of the Southern Hemisphere. Finally, we describe the key role of the Southern Ocean in influencing atmospheric chemistry and conclude with a description of the aims and scope of the newly formed IGAC Southern Hemisphere Working Group.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66941668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00073
K. Gupta, A. Mukhopadhyay, D. Babb, D. Barber, J. Ehn
Through analysis of Canadian Ice Service ice charts, we have characterized the temporal and spatial variability of landfast sea ice (or fast ice) surrounding Hudson Bay and James Bay from 2000 to 2019. Over this 19-year period, we observed contrasting changes in fast-ice persistence between the western and eastern sides of Hudson Bay and James Bay. Fast ice in western Hudson Bay and James Bay trended towards later freeze-up and earlier break-up that resulted in a shortening of the fast-ice season at a rate of 6 days/decade. Contrastingly, eastern Hudson Bay and James Bay showcased relatively earlier freeze-up and delayed break-up, and an overall trend towards a longer fast-ice season at a rate of 8 days/decade. The general trend in air temperature followed a similar spatial pattern to the changing fast-ice persistence; however, the timing of fast-ice break-up did not have a strong relationship with the thawing-degree days during spring. Variations in fast-ice area showed latitudinal and meridional gradients, with greater fast-ice area in eastern Hudson Bay and James Bay compared to the west. Given the overall warming trend in the Arctic, observing areas of decreasing fast-ice persistence is unexpected; however, this study highlights the role of regional factors, such as coastal orientation and bathymetry, in controlling the stability, growth and decay of fast ice.
{"title":"Landfast sea ice in Hudson Bay and James Bay","authors":"K. Gupta, A. Mukhopadhyay, D. Babb, D. Barber, J. Ehn","doi":"10.1525/elementa.2021.00073","DOIUrl":"https://doi.org/10.1525/elementa.2021.00073","url":null,"abstract":"Through analysis of Canadian Ice Service ice charts, we have characterized the temporal and spatial variability of landfast sea ice (or fast ice) surrounding Hudson Bay and James Bay from 2000 to 2019. Over this 19-year period, we observed contrasting changes in fast-ice persistence between the western and eastern sides of Hudson Bay and James Bay. Fast ice in western Hudson Bay and James Bay trended towards later freeze-up and earlier break-up that resulted in a shortening of the fast-ice season at a rate of 6 days/decade. Contrastingly, eastern Hudson Bay and James Bay showcased relatively earlier freeze-up and delayed break-up, and an overall trend towards a longer fast-ice season at a rate of 8 days/decade. The general trend in air temperature followed a similar spatial pattern to the changing fast-ice persistence; however, the timing of fast-ice break-up did not have a strong relationship with the thawing-degree days during spring. Variations in fast-ice area showed latitudinal and meridional gradients, with greater fast-ice area in eastern Hudson Bay and James Bay compared to the west. Given the overall warming trend in the Arctic, observing areas of decreasing fast-ice persistence is unexpected; however, this study highlights the role of regional factors, such as coastal orientation and bathymetry, in controlling the stability, growth and decay of fast ice.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66942039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00096
S. Nagalingam, R. Seco, K. Musaev, Chhandak Basu, Saewung Kim, A. Guenther
We present foliar biogenic volatile organic compound (BVOC) emission data from 24-h heat-stressed tomato (Solanum lycopersicum) seedlings including speciated monoterpenes and sesquiterpenes and high time-resolution measurements of methyl salicylate and total monoterpenes. The median total monoterpene and total sesquiterpene emission rates at 30°C were 18.5 and 0.172 pmol m–2 s–1, respectively, which falls within the negligible emission category of previous studies. However, initial heat exposure (39°C or 42°C) increased the emissions of approximately half of the targeted compounds beyond what was predicted by current BVOC emission temperature response algorithms. The enhanced emissions were not always sustained for the entire duration of the heat stress and some plants exhibited a delayed monoterpene response, where emissions peaked toward the end of the heat treatment. Methyl salicylate, a known stress marker, responded differently to the heat stress than most of the other compounds. Heat stress increased methyl salicylate emissions in some plants (at least initially), but in others, emissions declined or did not change significantly. There was no significant correlation between the magnitude of gene expression and emission induction of monoterpenes or methyl salicylate. Furthermore, the emitted monoterpenes did not exhibit any apparent light-dependent behavior, which suggests that these monoterpene stress emissions mostly originated from light-independent foliar storage pools and not from increased de novo production. In contrast, methyl salicylate emissions appear to have contributions from both de novo synthesis and stored pools, as they showed both enzyme-controlled (i.e., light-dependent) and light-independent behaviors. Analyses of the foliar essential oils demonstrate that most of the emitted BVOCs were also present in stored pools. The pool sizes were generally large enough to sustain unstressed emission levels for days to months, and even years for some compounds. However, heat-induced emission enhancement can diminish the pool sizes of some BVOCs, which could decrease subsequent emissions.
{"title":"Impact of heat stress on foliar biogenic volatile organic compound emission and gene expression in tomato (Solanum lycopersicum) seedlings","authors":"S. Nagalingam, R. Seco, K. Musaev, Chhandak Basu, Saewung Kim, A. Guenther","doi":"10.1525/elementa.2021.00096","DOIUrl":"https://doi.org/10.1525/elementa.2021.00096","url":null,"abstract":"We present foliar biogenic volatile organic compound (BVOC) emission data from 24-h heat-stressed tomato (Solanum lycopersicum) seedlings including speciated monoterpenes and sesquiterpenes and high time-resolution measurements of methyl salicylate and total monoterpenes. The median total monoterpene and total sesquiterpene emission rates at 30°C were 18.5 and 0.172 pmol m–2 s–1, respectively, which falls within the negligible emission category of previous studies. However, initial heat exposure (39°C or 42°C) increased the emissions of approximately half of the targeted compounds beyond what was predicted by current BVOC emission temperature response algorithms. The enhanced emissions were not always sustained for the entire duration of the heat stress and some plants exhibited a delayed monoterpene response, where emissions peaked toward the end of the heat treatment. Methyl salicylate, a known stress marker, responded differently to the heat stress than most of the other compounds. Heat stress increased methyl salicylate emissions in some plants (at least initially), but in others, emissions declined or did not change significantly. There was no significant correlation between the magnitude of gene expression and emission induction of monoterpenes or methyl salicylate. Furthermore, the emitted monoterpenes did not exhibit any apparent light-dependent behavior, which suggests that these monoterpene stress emissions mostly originated from light-independent foliar storage pools and not from increased de novo production. In contrast, methyl salicylate emissions appear to have contributions from both de novo synthesis and stored pools, as they showed both enzyme-controlled (i.e., light-dependent) and light-independent behaviors. Analyses of the foliar essential oils demonstrate that most of the emitted BVOCs were also present in stored pools. The pool sizes were generally large enough to sustain unstressed emission levels for days to months, and even years for some compounds. However, heat-induced emission enhancement can diminish the pool sizes of some BVOCs, which could decrease subsequent emissions.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66942259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.1525/elementa.2021.00102
F. Chang, B. Cardinale
In plant communities, higher levels of taxonomic richness are often shown to be more efficient at utilization of limiting resources due to resource partitioning among taxa. While resource partitioning is also thought to be important in consumer communities, consumers also exhibit more complex interactions like omnivory. Omnivory is generally thought to reduce the effects of consumer richness on the consumption of prey resources; however, empirical tests of this prediction are rare. Here, we report the results of 2 complementary studies to test the hypothesis that omnivory reduces the positive effects of consumer taxonomic richness on prey resource consumption. First, we analyzed data from a dataset consisting of 1,100 freshwater lakes across the continental United States. We show that the relationship between consumer taxonomic richness and the summed biomass of resource prey (phytoplankton) is independent of the proportion of zooplankton (consumers) that are omnivores. However, consumption rates were not explicitly measured in this dataset so that we conducted in situ feeding experiments in 37 lakes near Ann Arbor, MI, USA, to measure omnivorous consumption (Omni) as the amount of smaller microzooplankton (<200 μm) consumed by larger nonherbivorous mesozooplankton. We also measured the amount of phytoplankton consumption (G) across a gradient of zooplankton taxonomic richness (zpSR). We showed that there was a positive association between zpSR and G, suggesting that G was increased by zooplankton diversity. However, the effects of zooplankton diversity on the G are not altered by the level of Omni among zooplankton. Although omnivory does not influence the effects of consumer diversity on prey consumption, we do not negate the impacts of omnivory on other ecosystem functions in aquatic systems. We attempt to address a question that is of general interest to the field of ecology, especially of aquatic ecology, because omnivory is known to be common in aquatic systems.
{"title":"Effects of consumer diversity on prey consumption are not influenced by omnivory","authors":"F. Chang, B. Cardinale","doi":"10.1525/elementa.2021.00102","DOIUrl":"https://doi.org/10.1525/elementa.2021.00102","url":null,"abstract":"In plant communities, higher levels of taxonomic richness are often shown to be more efficient at utilization of limiting resources due to resource partitioning among taxa. While resource partitioning is also thought to be important in consumer communities, consumers also exhibit more complex interactions like omnivory. Omnivory is generally thought to reduce the effects of consumer richness on the consumption of prey resources; however, empirical tests of this prediction are rare. Here, we report the results of 2 complementary studies to test the hypothesis that omnivory reduces the positive effects of consumer taxonomic richness on prey resource consumption. First, we analyzed data from a dataset consisting of 1,100 freshwater lakes across the continental United States. We show that the relationship between consumer taxonomic richness and the summed biomass of resource prey (phytoplankton) is independent of the proportion of zooplankton (consumers) that are omnivores. However, consumption rates were not explicitly measured in this dataset so that we conducted in situ feeding experiments in 37 lakes near Ann Arbor, MI, USA, to measure omnivorous consumption (Omni) as the amount of smaller microzooplankton (<200 μm) consumed by larger nonherbivorous mesozooplankton. We also measured the amount of phytoplankton consumption (G) across a gradient of zooplankton taxonomic richness (zpSR). We showed that there was a positive association between zpSR and G, suggesting that G was increased by zooplankton diversity. However, the effects of zooplankton diversity on the G are not altered by the level of Omni among zooplankton. Although omnivory does not influence the effects of consumer diversity on prey consumption, we do not negate the impacts of omnivory on other ecosystem functions in aquatic systems. We attempt to address a question that is of general interest to the field of ecology, especially of aquatic ecology, because omnivory is known to be common in aquatic systems.","PeriodicalId":54279,"journal":{"name":"Elementa-Science of the Anthropocene","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66942426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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