scholarly journals Carbon evasion/accumulation ratio in boreal lakes is linked to nitrogen

2013 ◽  
Vol 27 (2) ◽  
pp. 363-374 ◽  
Author(s):  
Pirkko Kortelainen ◽  
Miitta Rantakari ◽  
Hannu Pajunen ◽  
Jari T. Huttunen ◽  
Tuija Mattsson ◽  
...  
Keyword(s):  
Boreal Lakes ◽  
Accumulation Ratio

scholarly journals Effects of climate change and industrialization on Lake Bolshoe Toko, eastern Siberia

2021 ◽  
Vol 65 (3) ◽  
pp. 335-352
Author(s):  
Boris K. Biskaborn ◽  
Biljana Narancic ◽  
Kathleen R. Stoof-Leichsenring ◽  
Lyudmila A. Pestryakova ◽  
Peter G. Appleby ◽  
...  
Keyword(s):  
Climate Change ◽  
Nineteenth Century ◽  
Deep Water ◽  
Boreal Lakes ◽  
Lake Ecosystem ◽  
Intermediate Water ◽  
Eastern Siberia ◽  
Natural Ecosystems ◽  
Planktonic Diatoms ◽  
Recent Climate

AbstractIndustrialization in the Northern Hemisphere has led to warming and pollution of natural ecosystems. We used paleolimnological methods to explore whether recent climate change and/or pollution had affected a very remote lake ecosystem, i.e. one without nearby direct human influence. We compared sediment samples that date from before and after the onset of industrialization in the mid-nineteenth century, from four short cores taken at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko, eastern Siberia. We analyzed diatom assemblage changes, including diversity estimates, in all four cores and geochemical changes (mercury, nitrogen, organic carbon) from one core taken at an intermediate water depth. Chronologies for two cores were established using 210Pb and 137Cs. Sedimentation rates were 0.018 and 0.033 cm year−1 at the shallow- and deep-water sites, respectively. We discovered an increase in light planktonic diatoms (Cyclotella) and a decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites, related to more recent warmer air temperatures and shorter periods of lake-ice cover, which led to pronounced thermal stratification. Diatom beta diversity in shallow-water communities changed significantly because of the development of new habitats associated with macrophyte growth. Mercury concentrations increased by a factor of 1.6 since the mid-nineteenth century as a result of atmospheric fallout. Recent increases in the chrysophyte Mallomonas in all cores suggested an acidification trend. We conclude that even remote boreal lakes are susceptible to the effects of climate change and human-induced pollution.

Altitude controls carbon dioxide in boreal lakes

Eos ◽  
2012 ◽  
Vol 93 (38) ◽  
pp. 372-372
Author(s):  
Atreyee Bhattacharya
Keyword(s):  
Carbon Dioxide ◽  
Boreal Lakes

Evaluating the integrity of C and O isotopes in sub-fossil wood from boreal lakes

2012 ◽  
Vol 348-349 ◽  
pp. 21-31 ◽  
Author(s):  
Martine M. Savard ◽  
Christian Bégin ◽  
Joëlle Marion ◽  
Dominique Arseneault ◽  
Yves Bégin
Keyword(s):  
Fossil Wood ◽  
Boreal Lakes ◽  
O Isotopes ◽  
C And O Isotopes

Occurrence and toxicity of cyanobacterial blooms dominated by Anabaena lemmermannii P. Richter and Aphanizomenon spp. in boreal lakes in 2003

2005 ◽  
Vol 117 ◽  
pp. 315-328 ◽  
Author(s):  
Liisa Lepistö ◽  
Jarkko Rapala ◽  
Christina Lyra ◽  
Katri A. Berg ◽  
Kirsti Erkomaa ◽  
...  
Keyword(s):  
Boreal Lakes ◽  
Cyanobacterial Blooms

THE PHYSIOLOGY OF HOST-PARASITE RELATIONS: IX. FURTHER OBSERVATIONS ON THE ACCUMULATION OF RADIOACTIVE SUBSTANCES AT RUST INFECTIONS

1961 ◽  
Vol 39 (6) ◽  
pp. 1393-1407 ◽  
Author(s):  
Michael Shaw
Keyword(s):  
Specific Activity ◽  
Dry Weight ◽  
Insoluble Fraction ◽  
Pentose Phosphate ◽  
Accumulation Ratio ◽  
X Ray ◽  
Specific Activities ◽  
Leaf Segments ◽  
Wheat Leaves ◽  
Host Parasite

Wang (Can. J. Botany, 38, 635–642 (1960)) concluded that the accumulation of radioactivity observed on radioautographs at infection sites on rusted leaves fed with C14-labelled substances was 'apparent' rather than real. The ‘accumulation ratio’ is defined as the ratio of the specific activities (c.p.m./mg dry weight of intact tissue) of rust-infected to uninfected areas of infected leaves. Theoretical considerations relating to the radioautography of leaves labelled with C14 and to the measurement of ‘accumulation ratios’ by extraction of C14-labelled substances from rusted and uninfected segments of infected leaves, as well as experimental data, show that Wang's conclusion is not generally applicable.Experimentally, it was shown using polymethacrylate C14 sources that differences in distance between sources and X-ray film of the order of 100 μ had no effect on the intensity of autoradiographs. Rust-infected leaves, fed with radioactive glucose, were radiographed between X-ray plates. Localization of radioactivity at infection sites was observed on both ‘dorsal’ and ‘ventral’ radiographs, indicating a real accumulation per unit area. Ventral were more radioactive than dorsal surfaces. The main development of the fungus occurred on the former. Radioautography revealed that C14 from glucose-1-C14, glucose-6-C14, and uniformly labelled glucose fed to excised wheat leaves became localized at 10-day-old rust infections in 2 hours. ‘Accumulation ratios’ calculated from the specific activity of leaf segments remained close to 1.0 for at least 6 hours after introduction of the tracer, but increased to more than 2 after 24 hours. When ‘accumulation ratios’ were calculated from the specific activities of individual pustules (excised with a punch 1 mm in diameter) and interpustular disks, values greater than 1 were observed in 2 hours, thus confirming the results of autoradiography. Differences between the ‘accumulation ratios’ observed with glucose-6-C14 and glucose-1-C14 were consistent with an increased role of the pentose phosphate pathway at infection sites. Incorporation of C14 from uniformly labelled glucose into the alcohol-insoluble fraction of rusted leaf segments was 2.5-fold that in uninfected segments in 6 hours and 3.65-fold in 24 hours. The humin formed during hydrochloric acid hydrolysis accounted for approximately 50% of the activity of the alcohol-insoluble material. The ‘accumulation ratio’ for the alcohol-soluble material was only 1.56 after 24 hours.All the results support the view (Shaw and Samborski, Can. J. Botany, 34, 389–405 (1956)) that there is a quantitative, metabolically dependent accumulation of C14 from radioactive glucose at vigorous rust infections. The relative roles of fungus and host in this process are discussed briefly.

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