Holocene Environmental Variability in the Arctic Gateway

2014 ◽  
pp. 37-42 ◽  
Author(s):  
Robert F. Spielhagen ◽  
Juliane Müller ◽  
Axel Wagner ◽  
Kirstin Werner ◽  
Gerrit Lohmann ◽  
...  
Keyword(s):  
Environmental Variability ◽  
The Arctic

scholarly journals Microbial Abundance and Enzyme Activity Patterns: Response to Changing Environmental Characteristics along a Transect in Kongsfjorden (Svalbard Islands)

2020 ◽  
Vol 8 (10) ◽  
pp. 824
Author(s):  
Gabriella Caruso ◽  
Alice Madonia ◽  
Simone Bonamano ◽  
Stefano Miserocchi ◽  
Federico Giglio ◽  
...  
Keyword(s):  
Bacterial Abundance ◽  
Environmental Variability ◽  
Heterotrophic Bacteria ◽  
Inorganic Compounds ◽  
Activity Patterns ◽  
The Arctic ◽  
Microbial Abundance ◽  
Ice Melting ◽  
Svalbard Archipelago ◽  
Chl A

Svalbard archipelago is experiencing the effects of climate changes (i.e., glaciers’ thickness reduction and glacier front retreat), but how ice melting affects water biogeochemistry is still unknown. Microbial communities often act as environmental sentinels, modulating their distribution and activity in response to environmental variability. To assess microbial response to climate warming, within the ARctic: present Climatic change and pAst extreme events (ARCA) project, a survey was carried out along a transect in Konsfjorden from off-shore stations towards the Kronebreen glacier. Total bacterial abundance and the fraction of actively respiring cells (labelled by cyanotetrazolium chloride, CTC), cultivable heterotrophic bacterial abundance, and extracellular enzymatic activities (leucine aminopeptidase (LAP), beta-glucosidase (GLU), and alkaline phosphatase (AP)) were measured. In addition, water temperature, salinity, dissolved oxygen, turbidity, total suspended matter (TSM), particulate and chromophoric dissolved organic matter (CDOM), chlorophyll-a (Chl-a), and inorganic compounds were determined, in order to evaluate whether variations in microbial abundance and metabolism were related with changes in environmental variables. Colder waters at surface (3.5–5 m) depths and increased turbidity, TSM, and inorganic compounds found at some hydrological stations close to the glacier were signals of ice melting. CDOM absorption slope values (275–295 nm) varied from 0.0077 to 0.0109 nm−1, and total bacterial cell count and cultivable heterotrophic bacterial abundance were in the order of 106 cells/mL and 103 colony forming units/mL, respectively. Enzymatic rates <1.78, 1.25, and 0.25 nmol/L/h were recorded for AP, LAP, and GLU, respectively. Inorganic compounds, TSM, and turbidity correlated inversely with temperature; AP was significantly related with CDOM absorption spectra and heterotrophic bacteria (r = 0.59, 0.71, p < 0.05); and LAP with Chl-a, Particulate Organic Carbon (POC) and Particulate Organic Nitrogen (PON) (0.97, 0.780, 0.734, p < 0.01), suggesting that fresh material from ice melting stimulated the metabolism of the cultivable fraction.

scholarly journals Atmospheric composition and thermodynamic retrievals from the ARIES airborne TIR-FTS system – Part 2: Validation and results from aircraft campaigns

2014 ◽  
Vol 7 (12) ◽  
pp. 4401-4416 ◽  
Author(s):  
G. Allen ◽  
S. M. Illingworth ◽  
S. J. O'Shea ◽  
S. Newman ◽  
A. Vance ◽  
...  
Keyword(s):  
Evaluation System ◽  
Environmental Variability ◽  
Trace Gases ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Trace Gas ◽  
Atmospheric Measurements ◽  
Validation Experiment ◽  
Process Studies ◽  
The Uk

Abstract. This study validates trace gas and thermodynamic retrievals from nadir infrared spectroscopic measurements recorded by the UK Met Office Airborne Research Interferometer Evaluation System (ARIES) – a thermal infrared, Fourier transform spectrometer (TIR-FTS) on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Trace-gas-concentration and thermodynamic profiles have been retrieved and validated for this study throughout the troposphere and planetary boundary layer (PBL) over a range of environmental variability using data from aircraft campaigns over and around London, the US Gulf Coast, and the Arctic Circle during the Clear air for London (ClearfLo), Joint Airborne IASI (Infrared Atmospheric Sounding Interferometer) Validation Experiment (JAIVEx), and Measurements, process studies, and Modelling (MAMM) aircraft campaigns, respectively. Vertically resolved retrievals of temperature and water vapour (H2O), and partial-column retrievals of methane (CH4), carbon monoxide (CO), and ozone (O3) (over both land and sea) were compared to corresponding measurements from high-precision in situ analysers and dropsondes operated on the FAAM aircraft. Average degrees of freedom for signal (DOFS) over a 0–9 km column range were found to be 4.97, 3.11, 0.91, 1.10, and 1.62 for temperature, H2O, CH4, CO, and O3, respectively, when retrieved on 10 vertical levels. Partial-column mean biases (and bias standard error) between the surface and ~ 9 km, when averaged across all flight campaigns, were found to be −0.7(±0.3) K, −479(±56) ppm, −11(±2) ppb, −3.3(±1.0) ppb, and +3.5(±1.0) ppb, respectively, whilst the typical a posteriori (total) uncertainties for individually retrieved profiles were 0.4, 9.5, 5.0, 21.2, and 15.0 %, respectively. Averaging kernels (AKs) derived for progressively lower altitudes show improving sensitivity to lower atmospheric layers when flying at lower altitudes. Temperature and H2O display significant vertically resolved sensitivity throughout the column, whilst trace gases are usefully retrieved only as partial-column quantities, with maximal sensitivity for trace gases other than H2O within a layer 1 and 2 km below the aircraft. This study demonstrates the valuable atmospheric composition information content that can be obtained by ARIES nadir TIR remote sensing for atmospheric process studies.

Bioeconomic analysis accounting for environmental effects in data-poor fisheries: The Northern Labrador Arctic Charr

2021 ◽  
Author(s):  
Melina Kourantidou ◽  
Di Jin ◽  
Andrew R Solow
Keyword(s):  
Climate Variability ◽  
Environmental Variability ◽  
Arctic Charr ◽  
Fishing Effort ◽  
The Arctic ◽  
Optimal Harvesting ◽  
Equilibrium Conditions ◽  
Complex Interactions ◽  
Optimal Harvest ◽  
Data Deficient

Fisheries managers call for more nuanced understandings of complex interactions between exploitation and environmental variability, especially in data poor settings. We develop a bioeconomic model for the Arctic Charr out of Nain, Northern Labrador, incorporating climate variability into growth. We derive parameters necessary for the bioeconomic analysis through optimization and identify optimal equilibrium conditions for the model with and without climate variability. Accounting for variability results in a slightly higher optimal harvest, fishing effort and stock. We find an optimal effort of 591 fishing weeks and harvest of 156,920kg for 2014, suggesting that both were below optimal. We further find that increased temperature leads to higher optimal effort and net benefits at steady state. Despite numerous uncertainties, data and knowledge gaps limiting the accuracy of our estimates, this is the first effort to identify the equilibrium harvesting conditions for this, currently uneconomic, yet socially and culturally important fishery. The methodology can be applicable to other data-deficient fisheries with similar challenges and unknowns, to advance the understanding of socially optimal harvesting and interactions with environmental variability.

scholarly journals Multidecadal dynamics of the Arctic copepod Limnocalanus macrurus in relation to environmental variability in the Baltic Sea

2019 ◽  
Vol 76 (7) ◽  
pp. 2427-2436 ◽  
Author(s):  
Heli Einberg ◽  
Riina Klais ◽  
Gunta Rubene ◽  
Georgs Kornilovs ◽  
Ivars Putnis ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Water Temperature ◽  
Environmental Variability ◽  
The Arctic ◽  
The Baltic Sea ◽  
Bottom Water Temperature ◽  
Limnocalanus Macrurus ◽  
The Baltic ◽  
Winter Severity

Abstract The Arctic Limnocalanus macrurus is a prominent representative of large copepods which performs several essential functions in freshwater and marine ecosystems. Being a cold stenotherm species, its distribution is primarily confined to deeper water layers. Based on the long-term observations from one of the largest spatially confined natural populations of this species in the Baltic Sea, we detected profound long-term variability of L. macrurus during 1958–2016: high abundances before the 1980s, then nearly disappearance in the 1990s and recovery in the 2000s. The main environmental parameters explaining the interannual variability of L. macrurus in spring were herring spawning stock biomass in preceding year, winter severity, and bottom water temperature in preceding summer. The effect of winter severity and water temperature was also non-linear. The sliding window correlation analysis pointed to a non-stationary relationship between the abundance of L. macrurus and the key variables. Given the observed pronounced seasonality in the population structure of L. macrurus (young stages dominated in the beginning of the year and only adults were left in the population in summer and autumn) we identified the dynamics of key environmental variables to understand this species under different ecosystem configurations and different combinations of drivers of change.

scholarly journals The Little Auk Alle alle: an ecological indicator of a changing Arctic and a model organism

Polar Biology ◽  
2021 ◽  
Author(s):  
Katarzyna Wojczulanis-Jakubas ◽  
Dariusz Jakubas ◽  
Lech Stempniewicz
Keyword(s):  
Parental Care ◽  
Large Scale ◽  
Environmental Variability ◽  
Large Population ◽  
Model Organism ◽  
Terrestrial Ecosystems ◽  
The Arctic ◽  
Ecological Indicator ◽  
Little Auk ◽  
Alle Alle

AbstractThe Little Auk Alle alle is a small planktivorous auk breeding colonially in the High Arctic. Owing to its large population size and bi-environmental lifestyle, resulting in the large-scale transport of matter from sea to land, the Little Auk is one of the most important components of the marine and terrestrial ecosystems in the Arctic. As a result of globalization, which facilitates access to remote areas of the Earth, a growing number of studies is being dedicated to this endemic Arctic seabird. Research has focussed primarily on the importance of the Little Auk as an ecological indicator reacting to the climatic and oceanological changes that are particularly evident in the Arctic as a result of Arctic amplification (warming is more rapid in the Arctic than in any other region on Earth). Importantly, the species is also used as a model to investigate matter and energy flow through the ecosystem, mate choice, parental care and biological rhythms. Here, we review the natural history of the Little Auk, highlighting studies with the potential to provide answers to universal questions regarding the response of seabirds to climate variability and avian reproductive behaviour, e.g. threshold of foraging flexibility in response to environmental variability, carry-over effects between the breeding and non-breeding periods, the reasons for the transition from bi- to uni-parental care, parental coordination mechanisms.

scholarly journals Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

2013 ◽  
Vol 10 (9) ◽  
pp. 5911-5929 ◽  
Author(s):  
H. Link ◽  
G. Chaillou ◽  
A. Forest ◽  
D. Piepenburg ◽  
P. Archambault
Keyword(s):  
Environmental Variability ◽  
Environmental Parameters ◽  
The Arctic ◽  
Sediment Surface ◽  
Benthic Fluxes ◽  
Short Term ◽  
Chl A ◽  
Water Oxygen ◽  
The Impact

Abstract. The effects of climate change on Arctic marine ecosystems and their biogeochemical cycles are difficult to predict given the complex physical, biological and chemical interactions among the ecosystem components. We studied benthic biogeochemical fluxes in the Arctic and the influence of short-term (seasonal to annual), long-term (annual to decadal) and other environmental variability on their spatial distribution to provide a baseline for estimates of the impact of future changes. In summer 2009, we measured fluxes of dissolved oxygen, nitrate, nitrite, ammonia, soluble reactive phosphate and silicic acid at the sediment–water interface at eight sites in the southeastern Beaufort Sea at water depths from 45 to 580 m. The spatial pattern of the measured benthic boundary fluxes was heterogeneous. Multivariate analysis of flux data showed that no single or reduced combination of fluxes could explain the majority of spatial variation, indicating that oxygen flux is not representative of other nutrient sink–source dynamics. We tested the influence of eight environmental parameters on single benthic fluxes. Short-term environmental parameters (sinking flux of particulate organic carbon above the bottom, sediment surface Chl a) were most important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters (porosity, surface manganese and iron concentration, bottom water oxygen concentrations) together with δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes. Variation in pigments at the sediment surface was most important to explain variation in fluxes of silicic acid. In a model including all fluxes synchronously, the overall spatial distribution could be best explained (57%) by the combination of sediment Chl a, phaeopigments, δ13Corg, surficial manganese and bottom water oxygen concentration. We conclude that it is necessary to consider long-term environmental variability along with rapidly ongoing environmental changes to predict the flux of oxygen and nutrients across Arctic sediments even at short timescales. Our results contribute to improve ecological models predicting the impact of climate change on the functioning of marine ecosystems.

scholarly journals Multivariate benthic ecosystem functioning in the Arctic – benthic fluxes explained by environmental parameters in the southeastern Beaufort Sea

2012 ◽  
Vol 9 (11) ◽  
pp. 16933-16976 ◽  
Author(s):  
H. Link ◽  
G. Chaillou ◽  
A. Forest ◽  
D. Piepenburg ◽  
P. Archambault
Keyword(s):  
Spatial Variation ◽  
Bottom Water ◽  
Environmental Variability ◽  
Environmental Parameters ◽  
The Arctic ◽  
Benthic Fluxes ◽  
Short Term ◽  
Water Oxygen ◽  
The Impact

Abstract. The effects of climate change on Arctic marine ecosystems and their biogeochemical cycles are difficult to predict given the complex physical, biological and chemical interactions among the ecosystem components. To predict the impact of future changes on benthic biogeochemical fluxes in the Arctic, it is important to understand the influence of short-term (seasonal to annual), long-term (annual to decadal) and other environmental variability on their spatial distribution. In summer 2009, we measured fluxes of dissolved oxygen, nitrate, nitrite, ammonia, soluble reactive phosphate and silicic acid at the sediment-water interface at eight sites in the southeastern Beaufort Sea at water depths from 45 to 580 m to address the following question and hypotheses using a statistical approach: (1) What is the spatial variation of benthic boundary fluxes (sink and source)? (2) The classical proxy of benthic activity, oxygen flux, does not determine overall spatial variation in fluxes. (3) A different combination of environmental conditions that vary either on a long-term (decadal) or short-term (seasonal to annual) scale determine each single flux. And (4) A combination of environmental conditions varying on the short and long-term scale drive the overall spatial variation in benthic boundary fluxes. The spatial pattern of the measured benthic boundary fluxes was heterogeneous. Multivariate analysis of flux data showed that no single or reduced combination of fluxes could explain the majority of spatial variation. We tested the influence of eight environmental parameters: sinking flux of particulate organic carbon above the bottom, sediment surface Chl a (both short-term), porosity, surface manganese and iron concentration, bottom water oxygen concentrations (all long-term), phaeopigments (intermediate-term influence) and Δ13Corg (terrestrial influence) on benthic fluxes. Short-term environmental parameters were most important for explaining oxygen, ammonium and nitrate fluxes. Long-term parameters together with Δ13Corg signature explained most of the spatial variation in phosphate, nitrate and nitrite fluxes. Sediment pigments and Δ13Corg levels in surficial sediments were most important to explain fluxes of silicic acid. The overall spatial distribution of fluxes could be best explained (57%) by the combination of sediment Chla, phaeopigments, Δ13Corg, surficial manganese and bottom water oxygen concentration. We conclude that it is necessary to consider long-term environmental variability in the prediction of the impact of ongoing short-term environmental changes on the flux of oxygen and nutrients in Arctic sediments. Our results contribute to improve ecological models predicting the impact if climate change on the functioning of marine ecosystems.

scholarly journals Atmospheric composition and thermodynamic retrievals from the ARIES airborne TIR-FTS system – Part 2: Validation and results from aircraft campaigns

2014 ◽  
Vol 7 (4) ◽  
pp. 3397-3441 ◽  
Author(s):  
G. Allen ◽  
S. M. Illingworth ◽  
S. J. O'Shea ◽  
S. Newman ◽  
A. Vance ◽  
...  
Keyword(s):  
Evaluation System ◽  
Degrees Of Freedom ◽  
Environmental Variability ◽  
Gulf Coast ◽  
Trace Gases ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Trace Gas ◽  
Atmospheric Measurements ◽  
The Uk

Abstract. This study validates trace gas and thermodynamic retrievals from nadir infrared spectroscopic measurements recorded by the UK Met Office Airborne Research Interferometer Evaluation System (ARIES) – a Thermal InfraRed Fourier Transform Spectrometer (TIR-FTS) on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Trace-gas-concentration and thermodynamic profiles have been retrieved and validated for this study throughout the troposphere and planetary boundary layer over a range of environmental variability using data from aircraft campaigns over and around London, the US Gulf Coast, and the Arctic Circle during the ClearfLo, JAIVEX, and MAMM aircraft campaigns, respectively. Vertically-resolved retrievals of temperature and water vapour (H2O), and partial-column retrievals of methane (CH4), carbon monoxide (CO), and ozone (O3), over both land and sea, were compared to corresponding measurements from high-precision in-situ analysers and dropsondes operated on the FAAM aircraft. Average Degrees of Freedom for Signal (DOFS) over a 0–9 km column range were found to be 4.97, 3.11, 0.91, 1.10, and 1.62 for temperature, H2O, CH4, CO, and O3, respectively, when retrieved on 10 vertical levels. Partial column mean biases (and 1σ bias) averaged across all flight campaigns were −0.4 (±1.9)%, −6.0 (±13.1)%, −0.6 (±2.1)%, −3.0(±18.4)%, and +4.7 (±24.9)%, respectively, while the typical total a posteriori errors for individually retrieved profiles were 0.4%, 9.5%, 5.0%, 21.2%, and 15.0%, respectively. Averaging kernels derived for progressively lower altitudes show improving sensitivity to lower atmospheric layers when flying at lower altitudes. Temperature and H2O display significant vertically resolved sensitivity throughout the column, whilst trace gases are usefully retrieved only as partial column quantities, with maximal sensitivity for trace gases other than H2O within a layer 1 km and 2 km below the aircraft. This study demonstrates the valuable atmospheric composition information content that can be obtained by ARIES nadir TIR remote sensing for atmospheric process studies.

The Arctic Climate System

2005 ◽  
Author(s):  
Mark C. Serreze ◽  
Roger G. Barry
Keyword(s):  
Climate System ◽  
Arctic Climate ◽  
The Arctic
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