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A 700-year paleoecological record of boreal ecosystem responses to climatic variation from Alaska.

https://arctichealth.org/en/permalink/ahliterature85780
Source
Ecology. 2008 Mar;89(3):729-43
Publication Type
Article
Date
Mar-2008
Author
Tinner Willy
Bigler Christian
Gedye Sharon
Gregory-Eaves Irene
Jones Richard T
Kaltenrieder Petra
Krähenbühl Urs
Hu Feng Sheng
Author Affiliation
Institute of Plant Sciences and Oeschger Center for Climate Change Research, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland. willy.tinner@ips.unibe.ch
Source
Ecology. 2008 Mar;89(3):729-43
Date
Mar-2008
Language
English
Publication Type
Article
Keywords
Alaska
Climate
Diatoms
Ecosystem
Fires
Forestry
Fossils
Geologic sediments
Greenhouse Effect
Ice Cover
Plant Physiology
Pollen
Time Factors
Trees
Abstract
Recent observations and model simulations have highlighted the sensitivity of the forest-tundra ecotone to climatic forcing. In contrast, paleoecological studies have not provided evidence of tree-line fluctuations in response to Holocene climatic changes in Alaska, suggesting that the forest-tundra boundary in certain areas may be relatively stable at multicentennial to millennial time scales. We conducted a multiproxy study of sediment cores from an Alaskan lake near the altitudinal limits of key boreal-forest species. Paleoecological data were compared with independent climatic reconstructions to assess ecosystem responses of the forest tundra boundary to Little Ice Age (LIA) climatic fluctuations. Pollen, diatom, charcoal, macrofossil, and magnetic analyses provide the first continuous record of vegetation fire-climate interactions at decadal to centennial time scales during the past 700 years from southern Alaska. Boreal-forest diebacks characterized by declines of Picea mariana, P. glauca, and tree Betula occurred during the LIA (AD 1500-1800), whereas shrubs (Alnus viridis, Betula glandulosa/nana) and herbaceous taxa (Epilobium, Aconitum) expanded. Marked increases in charcoal abundance and changes in magnetic properties suggest increases in fire importance and soil erosion during the same period. In addition, the conspicuous reduction or disappearance of certain aquatic (e.g., Isoetes, Nuphar, Pediastrum) and wetland (Sphagnum) plants and major shifts in diatom assemblages suggest pronounced lake-level fluctuations and rapid ecosystem reorganization in response to LIA climatic deterioration. Our results imply that temperature shifts of 1-2 degrees C, when accompanied by major changes in moisture balance, can greatly alter high-altitudinal terrestrial, wetland, and aquatic ecosystems, including conversion between boreal-forest tree line and tundra. The climatic and ecosystem variations in our study area appear to be coherent with changes in solar irradiance, suggesting that changes in solar activity contributed to the environmental instability of the past 700 years.
PubMed ID
18459336 View in PubMed
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Alder, Nitrogen, and Lake Ecology: Terrestrial-Aquatic Linkages in the Postglacial History of Lone Spruce Pond, Southwestern Alaska.

https://arctichealth.org/en/permalink/ahliterature284914
Source
PLoS One. 2017;12(1):e0169106
Publication Type
Article
Date
2017
Author
Bianca B Perren
Yarrow Axford
Darrell S Kaufman
Source
PLoS One. 2017;12(1):e0169106
Date
2017
Language
English
Publication Type
Article
Keywords
Alaska
Alnus - growth & development - metabolism
Animals
Biota
Climate
Climate change
Diatoms - physiology
Ecosystem
Geologic Sediments - chemistry
Lakes - chemistry
Nitrogen - metabolism
Picea - growth & development - metabolism
Ponds - chemistry
Soil
Abstract
Diatoms, combined with a multiproxy study of lake sediments (organic matter, N, d15N, d13C, biogenic silica, grain size, Cladocera and chironomids, Alnus pollen) from Lone Spruce Pond, Alaska detail the late-glacial to Holocene history of the lake and its response to regional climate and landscape change over the last 14.5 cal ka BP. We show that the immigration of alder (Alnus viridis) in the early Holocene marks the rise of available reactive nitrogen (Nr) in the lake as well as the establishment of a primarily planktonic diatom community. The later establishment of diatom Discostella stelligera is coupled to a rise of sedimentary d15N, indicating diminished competition for this nutrient. This terrestrial-aquatic linkage demonstrates how profoundly vegetation may affect soil geochemistry, lake development, and lake ecology over millennial timescales. Furthermore, the response of the diatom community to strengthened stratification and N levels in the past confirms the sensitivity of planktonic diatom communities to changing thermal and nutrient regimes. These past ecosystem dynamics serve as an analogue for the nature of threshold-type ecological responses to current climate change and atmospheric nitrogen (Nr) deposition, but also for the larger changes we should anticipate under future climate, pollution, and vegetation succession scenarios in high-latitude and high-elevation regions.
Notes
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PubMed ID
28076393 View in PubMed
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[Algo-bacterial communities of the Kulunda steppe (Altai region, Russia) soda lakes].

https://arctichealth.org/en/permalink/ahliterature262610
Source
Mikrobiologiia. 2015 Jan-Feb;84(1):107-19
Publication Type
Article
Author
O S Samylina
F V Sapozhnikov
O Iu Gainanova
A V Riabova
M A Nikitin
D Iu Sorokin
Source
Mikrobiologiia. 2015 Jan-Feb;84(1):107-19
Language
Russian
Publication Type
Article
Keywords
Chlorophyta - classification - genetics - ultrastructure
Cyanobacteria - classification - genetics - ultrastructure
DNA, Algal - analysis - genetics
DNA, Bacterial - analysis - genetics
Diatoms - classification - genetics - ultrastructure
Grassland
Lakes - chemistry - microbiology
Molecular Typing
Phylogeny
RNA, Ribosomal, 16S - genetics
RNA, Ribosomal, 18S - genetics
Salinity
Siberia
Water Microbiology
Abstract
The composition and macroscopic structure of the floating oxygenic phototrophic communities from Kulunda steppe soda lakes (Petukhovskoe sodovoe, Tanatara VI, and Gorchiny 3) was described based on the data of the 2011 and 2012 expeditions (Winogradsky Institute of Microbiology). The algo-bacterial community with a green alga Ctenocladus circinnatus as an edificator was the typical one. Filamentous Geitlerinema sp. and Nodosilinea sp. were the dominant cyanobacteria. Apart from C. circinnatus, the algological component of the community contained unicellular green algae Dunaliella viridis and cf. Chlorella minutissima, as well as diatoms (Anomeoneis sphaerophora, Brchysira brebissonii, Brachysira zellensis, Mastogloia pusilla var. subcapitata, Nitzschia amphibia, Nitzschia communis, and Nitzschia sp.1). The latter have not been previously identified in the lakes under study. In all lakes, a considerable increase in salinity was found to result in changes in the composition and macroscopic structure of algo-bacterial communities.
PubMed ID
25916153 View in PubMed
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Annual Cycle of Freshwater Diatoms in the High Arctic Revealed by Multiparameter Fluorescent Staining.

https://arctichealth.org/en/permalink/ahliterature311425
Source
Microb Ecol. 2020 Oct; 80(3):559-572
Publication Type
Journal Article
Date
Oct-2020
Author
Eva Hejduková
Josef Elster
Linda Nedbalová
Author Affiliation
Department of Ecology, Faculty of Science, Charles University, Vinicná 7, 128 44, Prague 2, Czech Republic. eva.hejdukova@natur.cuni.cz.
Source
Microb Ecol. 2020 Oct; 80(3):559-572
Date
Oct-2020
Language
English
Publication Type
Journal Article
Keywords
Arctic Regions
Diatoms - physiology
Fresh Water
Life History Traits
Seasons
Staining and Labeling
Svalbard
Abstract
Diatoms (Bacillariophyceae) are important primary producers in a wide range of hydro-terrestrial habitats in polar regions that are characterized by many extreme environmental conditions. Nevertheless, how they survive periods of drought and/or freeze remains unknown. A general strategy of microorganisms to overcome adverse conditions is dormancy, but morphologically distinct diatom resting stages are rare. This study aimed to evaluate the annual cycle of freshwater diatoms in the High Arctic (Central Spitsbergen) and provide an insight into their physiological cell status variability. The diversity and viability of diatom cells were studied in samples collected five times at four study sites, tracing the key events for survival (summer vegetative season, autumn dry-freezing, winter freezing, spring melting, summer vegetative season [again]). For viability evaluation, a multiparameter fluorescent staining was used in combination with light microscopy and allowed to reveal the physiological status at a single-cell level. The proportions of the cell categories were seasonally and locality dependent. The results suggested that a significant portion of vegetative cells survive winter and provide an inoculum for the following vegetative season. The ice thickness significantly influenced spring survival. The thicker the ice layer was, the more dead cells and fewer other stages were observed. The influence of the average week max-min temperature differences in autumn and winter was not proven.
PubMed ID
32488483 View in PubMed
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Assessing mining impacts: The influence of background geochemical conditions on diatom and macroinvertebrate communities in subarctic streams.

https://arctichealth.org/en/permalink/ahliterature304294
Source
J Environ Manage. 2021 Jan 15; 278(Pt 2):111532
Publication Type
Journal Article
Date
Jan-15-2021
Author
Heikki Mykrä
Minna Kuoppala
Vesa Nykänen
Katri Tolonen
Jarno Turunen
Annika Vilmi
Satu Maaria Karjalainen
Author Affiliation
Finnish Environment Institute, Freshwater Centre, P.O. Box 413, FI-90014, Oulu, Finland. Electronic address: Heikki.mykra@ymparisto.fi.
Source
J Environ Manage. 2021 Jan 15; 278(Pt 2):111532
Date
Jan-15-2021
Language
English
Publication Type
Journal Article
Keywords
Animals
Biota
Diatoms
Ecosystem
Environmental monitoring
Invertebrates
Mining
Abstract
Mining has changed landscapes locally in northern Fennoscandia and there is an increasing pressure for exploitation of the remaining mineral deposits of the region. Mineral deposits, even if unmined, can strongly influence stream water chemistry, stream biological communities and the ability of organisms to tolerate stressors. Using data sampled from six mining areas with three active (gold and chrome), two closed (gold) and one planned mine (phosphate), we examined how mineral deposits and mining influence water chemistry and diatom and macroinvertebrate communities in subarctic streams in Finnish Lapland. We supplemented the data by additional samples compiled from databases and further assessed how variation in background geological conditions influences bioassessments of the impacts arising from mining. We found that water specific conductivity was elevated in our study streams draining through catchments with a high mineral potential. Mining effects were mainly seen as increased concentration of nitrogen. Influence of mineral deposits was detected in composition of diatom and macroinvertebrate communities, but communities in streams in areas with a high mineral potential were as diverse as those in streams in areas with a low mineral potential. Mining impacts were better detected for diatoms using a reference condition based on sites with a high than low mineral potential, while for macroinvertebrates, the responses were generally less evident, likely because of only minor effects of mining on water chemistry. Community composition and frequencies of occurrence of macroinvertebrate taxa were, however, highly similar between mine-influenced streams and reference streams with a high potential for minerals indicating that the communities are strongly structured by the natural influence of mineral deposits. Incorporating geochemistry into the reference condition would likely improve bioassessments of both taxonomic groups. Replicated monitoring in potentially impacted sites and reference sites would be the most efficient framework for detecting environmental impacts in streams draining through mineral-rich catchments.
PubMed ID
33130404 View in PubMed
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Atlantic walrus signal latitudinal differences in the long-term decline of sea ice-derived carbon to benthic fauna in the Canadian Arctic.

https://arctichealth.org/en/permalink/ahliterature303981
Source
Proc Biol Sci. 2020 12 09; 287(1940):20202126
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
12-09-2020
Author
David J Yurkowski
Thomas A Brown
Paul J Blanchfield
Steven H Ferguson
Author Affiliation
Fisheries and Oceans Canada, Winnipeg, Manitoba, R3T 2N6, Canada.
Source
Proc Biol Sci. 2020 12 09; 287(1940):20202126
Date
12-09-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Arctic Regions
Canada
Carbon
Climate change
Diatoms
Ecosystem
Food chain
Ice Cover
Phytoplankton
Walruses
Abstract
Climate change is altering the biogeochemical and physical characteristics of the Arctic marine environment, which impacts sea ice algal and phytoplankton bloom dynamics and the vertical transport of these carbon sources to benthic communities. Little is known about whether the contribution of sea ice-derived carbon to benthic fauna and nitrogen cycling has changed over multiple decades in concert with receding sea ice. We combined compound-specific stable isotope analysis of amino acids with highly branched isoprenoid diatom lipid biomarkers using archived (1982-2016) tissue of benthivorous Atlantic walrus to examine temporal trends of sea ice-derived carbon, nitrogen isotope baseline and trophic position of Atlantic walrus at high- and mid-latitudes in the Canadian Arctic. Associated with an 18% sea ice decline in the mid-Arctic, sea ice-derived carbon contribution to Atlantic walrus decreased by 75% suggesting a strong decoupling of sea ice-benthic habitats. By contrast, a nearly exclusive amount of sea ice-derived carbon was maintained in high-Arctic Atlantic walrus (98% in 1996 and 89% in 2006) despite a similar percentage in sea ice reduction. Nitrogen isotope baseline or the trophic position of Atlantic walrus did not change over time at either location. These findings indicate latitudinal differences in the restructuring of carbon energy sources used by Atlantic walrus and their benthic prey, and in turn a change in Arctic marine ecosystem functioning between sea ice-pelagic-benthic habitats.
PubMed ID
33290685 View in PubMed
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Biotransfer of ß-N-methylamino-L-alanine (BMAA) in a eutrophicated freshwater lake.

https://arctichealth.org/en/permalink/ahliterature270850
Source
Mar Drugs. 2015 Mar;13(3):1185-201
Publication Type
Article
Date
Mar-2015
Author
Sandra Lage
Heléne Annadotter
Ulla Rasmussen
Sara Rydberg
Source
Mar Drugs. 2015 Mar;13(3):1185-201
Date
Mar-2015
Language
English
Publication Type
Article
Keywords
Age Factors
Amino Acids, Diamino - analysis - isolation & purification
Animals
Cyanobacteria - metabolism
Diatoms - metabolism
Dinoflagellida - metabolism
Fishes - metabolism
Food chain
Lakes
Neurotoxins - analysis - isolation & purification
Risk factors
Sweden
Abstract
ß-N-Methylamino-L-alanine (BMAA), a neurotoxic non-protein amino acid, plays a significant role as an environmental risk factor in neurodegenerative diseases, such as amyotrophic lateral sclerosis. BMAA producers occur globally, colonizing almost all habitats and represent species from distinct phytoplanktonic groups, i.e., cyanobacteria, diatoms, and dinoflagellates. Bioaccumulation of BMAA in invertebrate and vertebrate organisms has also been registered around the globe. In the Baltic Sea, BMAA has been detected in several commercial fish species, raising the question of the bioaccumulation of BMAA in Swedish limnic systems. Here we find the presence of BMAA in water samples from Lake Finjasjön and identify its bioaccumulation patterns in both plankti-benthivorous and piscivorous fish, according to fish species, total weight, gender, and season of collection. For the first time, a large number of fish individuals were used in order to draw conclusions on BMAA bioaccumulation in a closed ecological community based on a statistical approach. We may, therefore, conclude that feeding patterns (plankti-benthivorous) and increased age of fish may lead to a higher tissue concentration of BMAA.
Notes
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PubMed ID
25738330 View in PubMed
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Source
Science. 2002 Aug 30;297(5586):1494-6
Publication Type
Article
Date
Aug-30-2002
Author
Kaiser Jocelyn
Source
Science. 2002 Aug 30;297(5586):1494-6
Date
Aug-30-2002
Language
English
Publication Type
Article
Keywords
Algae
Antarctic Regions
Cold Climate
Diatoms
Ecosystem
Evolution
Geologic sediments
Greenhouse Effect
Humans
Ice
Time
Notes
Erratum In: Science 2002 Sep 20;297(5589):1996
PubMed ID
12202815 View in PubMed
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Change of volatile components in six microalgae with different growth phases.

https://arctichealth.org/en/permalink/ahliterature283641
Source
J Sci Food Agric. 2017 Feb;97(3):761-769
Publication Type
Article
Date
Feb-2017
Author
Lv Zhou
Jiao Chen
Jilin Xu
Yan Li
Chengxu Zhou
Xiaojun Yan
Source
J Sci Food Agric. 2017 Feb;97(3):761-769
Date
Feb-2017
Language
English
Publication Type
Article
Keywords
Cell Cycle
China
Chlorophyta - chemistry - growth & development - metabolism
Chrysophyta - chemistry - growth & development - metabolism
Databases, Chemical
Diatoms - chemistry - growth & development - metabolism
Discriminant Analysis
Gas Chromatography-Mass Spectrometry
Microalgae - chemistry - growth & development - metabolism
Multivariate Analysis
Principal Component Analysis
Solid Phase Microextraction
Species Specificity
Volatile Organic Compounds - analysis - chemistry - metabolism
Volatilization
Abstract
Head space solid-phase microextraction-gas chromatography-mass spectrometry has been applied to analyze the volatile components of six marine microalgae (Thalassiosira weissflogii, Nitzschia closterium, Chaetoceros calcitrans, Platymonas helgolandica, Nannochloropsis spp. and Dicrateria inornata) from Bacillariophyta, Chlorophyta and Chrysophyta, respectively, in different growth phases.
All volatile compounds were identified by database searching in the NIST08 Mass Spectral Library and analyzed by principal component analysis with SIMCA-P software (Umetrics, Umea, Sweden). The results clearly revealed that the volatile components of the six microalgae were significantly different in the exponential, stationary and declining phases. Aldehydes, alkanes, some esters and dimethyl sulfide significantly changed in different growth phases.
This is the first report on the comprehensive characteristics of volatile components in different microalgae and in different growth phases. The results may provide reference data for studies on the flavor of cultivated aquatic organism, odor formation in nature water, choice of feeding period and microalgae species selection for the artificial rearing of marine organisms. © 2016 Society of Chemical Industry.
PubMed ID
27166980 View in PubMed
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Changing nutrient cycling in Lake Baikal, the world's oldest lake.

https://arctichealth.org/en/permalink/ahliterature304400
Source
Proc Natl Acad Sci U S A. 2020 11 03; 117(44):27211-27217
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
11-03-2020
Author
George E A Swann
Virginia N Panizzo
Sebastiano Piccolroaz
Vanessa Pashley
Matthew S A Horstwood
Sarah Roberts
Elena Vologina
Natalia Piotrowska
Michael Sturm
Andre Zhdanov
Nikolay Granin
Charlotte Norman
Suzanne McGowan
Anson W Mackay
Author Affiliation
School of Geography, University of Nottingham, Nottingham NG7 2RD, United Kingdom; george.swann@nottingham.ac.uk virginia.panizzo@nottingham.ac.uk.
Source
Proc Natl Acad Sci U S A. 2020 11 03; 117(44):27211-27217
Date
11-03-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Climate change
Diatoms
Ecosystem
Environmental Science - methods
Fresh Water - chemistry
Geologic sediments
Ice Cover
Lakes - analysis - chemistry
Nutrients - analysis
Russia
Siberia
Abstract
Lake Baikal, lying in a rift zone in southeastern Siberia, is the world's oldest, deepest, and most voluminous lake that began to form over 30 million years ago. Cited as the "most outstanding example of a freshwater ecosystem" and designated a World Heritage Site in 1996 due to its high level of endemicity, the lake and its ecosystem have become increasingly threatened by both climate change and anthropogenic disturbance. Here, we present a record of nutrient cycling in the lake, derived from the silicon isotope composition of diatoms, which dominate aquatic primary productivity. Using historical records from the region, we assess the extent to which natural and anthropogenic factors have altered biogeochemical cycling in the lake over the last 2,000 y. We show that rates of nutrient supply from deep waters to the photic zone have dramatically increased since the mid-19th century in response to changing wind dynamics, reduced ice cover, and their associated impact on limnological processes in the lake. With stressors linked to untreated sewage and catchment development also now impacting the near-shore region of Lake Baikal, the resilience of the lake's highly endemic ecosystem to ongoing and future disturbance is increasingly uncertain.
PubMed ID
33077588 View in PubMed
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64 records – page 1 of 7.