Reduced diversity and productivity of diatoms and other protists during the Early Holocene in the subarctic North Pacific

2020 ◽  
Author(s):  
Heike H. Zimmermann ◽  
Stefan Kruse ◽  
Kathleen R. Stoof-Leichsenring ◽  
Luise Schulte ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Green Algae ◽  
Taxonomic Diversity ◽  
Taxonomic Composition ◽  
Shotgun Sequencing ◽  
Early Holocene ◽  
The Past ◽  
Subarctic North Pacific ◽  
Morphological Differences ◽  
Marine Protists

<p>Marine protists are a phylogenetically diverse group of single-celled eukaryotes that respond sensitively to changes in environmental conditions. Yet, our understanding how long-term climate variability has shaped the taxonomic composition is mostly unknown, especially of non-biomineralizing groups, such as green algae, since traditional micropaleontological studies are limited to the analysis of microfossil remains with often hardly discernable morphological differences between species (e.g. diatoms). Here we present a sedimentary ancient DNA (<em>sed</em>aDNA) record of the marine sediment core SO201-2-12KL, which was retrieved from the eastern continental slope of Kamchatka at 2173 m water depth (N 53.992660°, E 162.375830°) and covers the past 19.9 thousand years. We applied <em>sed</em>aDNA metabarcoding to 63 samples using a diatom-specific, short plastid marker that is part of the <em>rbcL</em> gene. Additionally, we used metagenomic shotgun sequencing on a subset of 26 samples to investigate the overall taxonomic composition of protists. Metagenomic shotgun sequencing revealed a variety of unicellular plankton groups mostly from green algae (especially <em>Bathycoccus</em>) and diatoms. At 11.1 cal kyr BP only single sequences assigned to green algae, diatoms and coccolithophorids could be detected. Metabarcoding showed strong variability in the richness of diatom sequence variants, which was highest during Heinrich Stadial 1 and the Younger Dryas. From about 11.4 cal kyr BP diatom taxonomic diversity strongly decreased until about 10.7 cal kyr BP. This was associated with highest taxonomic and phylogenetic turnover recorded over the past 19.9 cal kyr. Concomitant with this we recorded sequences assigned to <em>Skeletonema</em> <em>subsalsum</em>, a coastal diatom associated with low salinities or freshwater. Tentatively, as we wait for the confirmation by further sequencing, we suggest that the reduced protist diversity during the Early Holocene resulted from sea surface freshening, which led to a strengthened vertical stratification which could have reduced past productivity due to limited nutrient supply from deeper waters to the photic zone.</p>

Assessment of small water bodies Sergiev Posad district on the taxonomic diversity of green, blue-green and diatom algae

2021 ◽  
pp. 18-32
Author(s):  
Alexander Viacheslavovich Gorbunov ◽  
Oleg Viacheslavovich Gorbunov ◽  
Nikita Il’ich Kochetkov ◽  
Dmitry Lvovich Nikiforov-Nikishin
Keyword(s):  
Species Diversity ◽  
Green Algae ◽  
Water Environment ◽  
Taxonomic Diversity ◽  
Systematic Position ◽  
Taxonomic Composition ◽  
Algal Flora ◽  
Frequency Of Occurrence ◽  
Large Species ◽  
Blue Green Algae

The purpose of the study was to determine the degree of saprobity of the artificial extension of the Vytravki riverbed (left tributary of the Dubna river) in the Sergiev Posad district of the Moscow region, based on the taxonomic composition of the pelagial and littoral algal flora. For this purpose, the systematic position of algae was determined using a number of domestic and foreign sources, as well as using the electronic database AlgaeBase. The most attention was paid to common indicator types, according to the literature data. Algological samples were taken in accordance with generally accepted methods; the main part of the samples was processed immediately after collection on site, the rest of the material was fixed with a formalin solution and Prat medium for detailed study in laboratory conditions under a microscope. According to the results of the study of hydrobiological samples, the composition of algal flora in the summer-autumn period was determined. There is a large species diversity of algae, represented by most of the divisions characteristic of the Central part of Russia. The green, diatomaceous, and blue-green algae divisions were the most represented. Maximum species diversity was observed for the genera Scenedesmus (9 species) and Pediastrum (10 species). Diatoms are the second group in terms of frequency of occurrence of species that live both in standing water and in rheophilic conditions. Blue-green algae were represented by pelagic forms, with a small frequency of occurrence. Among them, the genera Anabaena (5 species) and Microcystis (3 species) are notable for their high species diversity. The algal flora of the pond was marked divisions, dinophyceae and kropotova, typical for oligotrophic and distrophic reservoirs, indicating a high quality water environment. The established hydrochemical parameters of the reservoir were normal and were similar to the reservoirs of Central Russia at the end of the growing season, which were not exposed to anthropogenic impact.

scholarly journals Establishment of a cryopreserved biobank for the Culture Collection of Freshwater Microalgae (CCMA-UFSCar), São Paulo, Brazil

2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Leticia Piton Tessarolli ◽  
John Godfrey Day ◽  
Armando Augusto Henriques Vieira
Keyword(s):  
Green Algae ◽  
Biological Materials ◽  
Culture Collection ◽  
Freshwater Microalgae ◽  
The Past ◽  
The Stability ◽  
Taxonomic Groups ◽  
And Training ◽  
Term Maintenance

Abstract The Culture Collection of Freshwater Microalgae (CCMA-UFSCar, Coleção de Culturas de Microalgas de Água-Doce), based at the Universidade Federal de São Carlos, plays an important role in underpinning Brazilian microalgal research, providing biological materials, substrates and training personnel for a large proportion of the past and current projects in this area. However, recent efforts to expand the culture catalogue/holdings have reached a ceiling because of the logistical practicality of maintaining actively growing cultures. In order to reduce the costs associated with the maintenance regime of cultures, efforts were initiated on the establishment of a cryopreserved biobank for long term maintenance of cultures, thus minimizing the efforts associated with handling of material, as successfully frozen cultures, in theory, could be maintained effectively indefinitely, with the advantage of the stability of cells characteristics. Initial tests were performed on 93 strains including exemplar taxa across the different taxonomic groups in the collection catalogue. The highest levels of success were achieved for the smaller taxa, such as the small green algae; while for the larger and more complex organisms limited to no success was obtained. For the strains tested, over 70% had positive good levels of post-thaw viability and regenerated phenotypically normal cultures.

scholarly journals Fire hazard modulation by long-term dynamics in land cover and dominant forest type in eastern and central Europe

2020 ◽  
Vol 17 (5) ◽  
pp. 1213-1230 ◽  
Author(s):  
Angelica Feurdean ◽  
Boris Vannière ◽  
Walter Finsinger ◽  
Dan Warren ◽  
Simon C. Connor ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Biomass Burning ◽  
Forest Type ◽  
Fire Hazard ◽  
Fire Regimes ◽  
Early Holocene ◽  
Tree Cover ◽  
The Past

Abstract. Wildfire occurrence is influenced by climate, vegetation and human activities. A key challenge for understanding the risk of fires is quantifying the mediating effect of vegetation on fire regimes. Here, we explore the relative importance of Holocene land cover, land use, dominant functional forest type, and climate dynamics on biomass burning in temperate and boreo-nemoral regions of central and eastern Europe over the past 12 kyr. We used an extensive data set of Holocene pollen and sedimentary charcoal records, in combination with climate simulations and statistical modelling. Biomass burning was highest during the early Holocene and lowest during the mid-Holocene in all three ecoregions (Atlantic, continental and boreo-nemoral) but was more spatially variable over the past 3–4 kyr. Although climate explained a significant variance in biomass burning during the early Holocene, tree cover was consistently the highest predictor of past biomass burning over the past 8 kyr. In temperate forests, biomass burning was high at ∼45 % tree cover and decreased to a minimum at between 60 % and 70 % tree cover. In needleleaf-dominated forests, biomass burning was highest at ∼ 60 %–65 % tree cover and steeply declined at >65 % tree cover. Biomass burning also increased when arable lands and grasslands reached ∼ 15 %–20 %, although this relationship was variable depending on land use practice via ignition sources, fuel type and quantities. Higher tree cover reduced the amount of solar radiation reaching the forest floor and could provide moister, more wind-protected microclimates underneath canopies, thereby decreasing fuel flammability. Tree cover at which biomass burning increased appears to be driven by warmer and drier summer conditions during the early Holocene and by increasing human influence on land cover during the late Holocene. We suggest that long-term fire hazard may be effectively reduced through land cover management, given that land cover has controlled fire regimes under the dynamic climates of the Holocene.

scholarly journals Fire risk modulation by long-term dynamics in land cover and dominant forest type in Eastern and Central Europe

2019 ◽  
Author(s):  
Angelica Feurdean ◽  
Boris Vannière ◽  
Walter Finsinger ◽  
Dan Warren ◽  
Simon C. Connor ◽  
...  
Keyword(s):  
Land Cover ◽  
Fire Regime ◽  
Forest Type ◽  
Full Range ◽  
Fire Risk ◽  
Early Holocene ◽  
Tree Cover ◽  
Data Set ◽  
The Past

Abstract. Wildfire occurrence is influenced by climate, vegetation and human activities. A key challenge for understanding fire-climate-vegetation interactions is to quantify the effect vegetation has in mediating fire regime. Here, we explore the relative importance of Holocene land cover and dominant functional forest type, and climate dynamics on biomass burned in temperate and boreo-nemoral regions of Central and Eastern Europe over the past 12 ka BP years. We used an extensive data set of Holocene pollen and sedimentary charcoal records, in combination with climate simulations and novel statistical modelling. Biomass burned was highest during the early Holocene and lowest during the mid Holocene in all three ecoregions, but diverged more markedly over the past 3–4 ka BP. Although the climate was an important driver of fire hazard during the warm and dry early Holocene, tree cover was consistently the strongest predictor of past biomass burning. In temperate forests, biomass burned was high at ~ 45 % tree cover and decreased strongly towards 60 % tree cover. In needleleaf dominated forests, biomass burned was highest at ~ 60–65 % tree cover and abruptly declined at > 65 % tree cover. Biomass burned also increased when arable lands and grasslands reached ~ 15–20 %, although this relationship was highly dynamic depending on land use intensity throughout ignition and fuel type and availability. Our observations cover the full range of Holocene climate variability and land cover changes and illustrates that percentages of land cover is a key predictor of the probability of fire occurrence over timescales of centuries to millennia. We suggest that long-term fire risk may be effectively reduced through land cover management, given that land cover has controlled fire regimes under the dynamic climates of the Holocene.

Enabling Community Well-being Self-Monitoring in the Context of Mining: The Naskapi Nation of Kawawachikamach

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Robert Klinck ◽  
Ben Bradshaw ◽  
Ruby Sandy ◽  
Silas Nabinacaboo ◽  
Mannie Mameanskum ◽  
...  
Keyword(s):  
Indigenous Peoples ◽  
Well Being ◽  
Aboriginal Community ◽  
Self Monitoring ◽  
Community Engaged Research ◽  
The Past ◽  
Mineral Development ◽  
Iron Deposits ◽  
Term Monitoring

The Naskapi Nation of Kawawachikamach is an Aboriginal community located in northern Quebec near the Labrador Border. Given the region’s rich iron deposits, the Naskapi Nation has considerable experience with major mineral development, first in the 1950s to the 1980s, and again in the past decade as companies implement plans for further extraction. This has raised concerns regarding a range of environmental and socio-economic impacts that may be caused by renewed development. These concerns have led to an interest among the Naskapi to develop a means to track community well-being over time using indicators of their own design. Exemplifying community-engaged research, this paper describes the beginning development of such a tool in fall 2012—the creation of a baseline of community well-being against which mining-induced change can be identified. Its development owes much to the remarkable and sustained contribution of many key members of the Naskapi Nation. If on-going surveying is completed based on the chosen indicators, the Nation will be better positioned to recognize shifts in its well-being and to communicate these shifts to its partners. In addition, long-term monitoring will allow the Naskapi Nation to contribute to more universal understanding of the impacts of mining for Indigenous peoples.

Courting the Youth Vote in 2008: The Obama Effect

2009 ◽  
Vol 5 ◽  
Author(s):  
Lindsey C Bohl
Keyword(s):  
Presidential Elections ◽  
Voter Registration ◽  
The Internet ◽  
The Past ◽  
Several Variables ◽  
High Turnout ◽  
Short And Long Term ◽  
Use Of The Internet ◽  
Youth Vote

This paper examines a few of the numerous factors that may have led to increased youth turnout in 2008 Election. First, theories of voter behavior and turnout are related to courting the youth vote. Several variables that are perceived to affect youth turnout such as party polarization, perceived candidate difference, voter registration, effective campaigning and mobilization, and use of the Internet, are examined. Over the past 40 years, presidential elections have failed to engage the majority of young citizens (ages 18-29) to the point that they became inclined to participate. This trend began to reverse starting in 2000 Election and the youth turnout reached its peak in 2008. While both short and long-term factors played a significant role in recent elections, high turnout among youth voters in 2008 can be largely attributed to the Obama candidacy and campaign, which mobilized young citizens in unprecedented ways.

Impact of FII’s and FDI’s on Indian Stock Market

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Global Economy ◽  
Short Term ◽  
Earnings Growth ◽  
The Past ◽  
Bull Market ◽  
Indian Stock Market

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

2019 ◽  
Vol 20 (3) ◽  
pp. 251-264 ◽  
Author(s):  
Yinlu Feng ◽  
Zifei Yin ◽  
Daniel Zhang ◽  
Arun Srivastava ◽  
Chen Ling
Keyword(s):  
Chinese Medicine ◽  
Cell Therapy ◽  
Future Research ◽  
The Past ◽  
Promising Strategy ◽  
Wide Range ◽  
New Directions ◽  
Gene And Cell Therapy ◽  
Proteins And Peptides

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

Organizational Reforms as Routines

2017 ◽  
Author(s):  
Nils Brunsson
Keyword(s):  
Long Term Effects ◽  
The Past ◽  
Limited Experience

This chapter argues that organizational reforms are driven by problems to be addressed, by solutions to be applied, and by forgetfulness. The greater the supply of any of these factors, the more likely it is that reforms will occur. Without problems, reforms are difficult to justify; without solutions they cannot be formulated; and without forgetfulness there is a risk that people will be discouraged by the fact that similar reforms have been tried and have failed in the past. In contemporary large organizations, problems tend to be easily found. Those interested in selling solutions often try to supply problems as well — problems that can be solved by their solutions. Forgetfulness can be promoted by the use of consultants with limited experience of the implementation and long-term effects of reforms. Reforms are also self-referential; they tend to cause new reforms. Thus, reforms can be considered as routines: they are likely to be repeated over and over again.

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