Weather-driven ecology of planktonic diatoms in Lake Tovel (Trentino, Italy)

Hydrobiologia ◽  
2007 ◽  
Vol 578 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Monica Tolotti ◽  
Flavio Corradini ◽  
Adriano Boscaini ◽  
Damaso Calliari
Keyword(s):  
Planktonic Diatoms ◽  
Lake Tovel

Ultrastructure of Melosira resting cell rejuvenation

1984 ◽  
Vol 42 ◽  
pp. 734-735
Author(s):  
C. E. M. Bourne ◽  
L. Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Lake Michigan ◽  
Light And Electron Microscopy ◽  
Resting Cells ◽  
Planktonic Diatoms ◽  
Resting Cell ◽  
Vegetative Survival ◽  
Cytological Changes ◽  
Recent Attention ◽  
Freshwater Diatom

Much recent attention has been focused on vegetative survival forms of planktonic diatoms and other algae. There are several reports of extended vegetative survival of the freshwater diatom Melosira in lake sediments. In contrast to those diatoms which form a morphologically distinct resistant spore, Melosira is known to produce physiological resting cells that are indistinguishable in outward morphology from actively growing cells.We used both light and electron microscopy to document and elucidate the sequence of cytological changes during the transition from resting cells to actively growing cells in a population of Melosira granulata from Douglas Lake, Michigan sediments collected in mid-July of 1983.

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.

scholarly journals Dynamics of microalgal communities in the water-column/sediment interface of the inner shelf off Parana State, Southern Brazil

2004 ◽  
Vol 52 (3-4) ◽  
pp. 183-194 ◽  
Author(s):  
Ricardo Luiz Queiroz ◽  
Frederico Pereira Brandini ◽  
Franciane Maria Pellizzari
Keyword(s):  
Water Column ◽  
Cyanobacterial Bloom ◽  
Interface Layer ◽  
Benthic Diatoms ◽  
Southern Brazil ◽  
Planktonic Diatoms ◽  
Cell Densities ◽  
Sediment Interface ◽  
Microalgal Community

The composition and biomass of the microalgal community at the water-column/sediment interface on the continental shelf off Parana State (Brazil) were studied every 2 months during 1999. Samples for cell identification and determination of chlorophyll a were taken from the interface layer and at discrete depths up to 4 m above the sediment. Results showed a community mainly formed by benthic and planktonic diatoms >30 µm, benthic diatoms <30 µm and cyanobacteria. Cell densities were generally higher at the interface layer. Resuspension and sedimentation events seemed to be a paramount factor regulating the composition and biomass of these communities, and affected differently cells of different size classes. Cells >30 µm, which accounted for most of the pigment biomass, were resuspended from the interface after turbulent periods, and may take advantage of calm periods to stay and grow at the interface. Small benthic diatoms were more susceptible to wind-induced turbulence occurring in higher densities in the water column just above the water-sediment interface. A cyanobacterial bloom (Trichodesmiun) was observed at these bottom layers in the spring-summer periods.

Phytoplankton in the embayments of King George Island (Antarctic Peninsula): a review with emphasis on diatoms

Polar Record ◽  
2018 ◽  
Vol 54 (2) ◽  
pp. 158-175 ◽  
Author(s):  
Priscila Kienteca Lange ◽  
Ryszard Ligowski ◽  
Denise Rivera Tenenbaum
Keyword(s):  
Antarctic Peninsula ◽  
Early Summer ◽  
Western Antarctic Peninsula ◽  
King George Island ◽  
Accurate Identification ◽  
Phytoplankton Assemblages ◽  
Marine Food Web ◽  
Planktonic Diatoms ◽  
Local Material ◽  
Marine Food

ABSTRACTConsidering that phytoplankton assemblages are good bioindicators of environmental conditions, the sensitivity of the Western Antarctic Peninsula (WAP) to climate change, and the importance of some areas of its islands as Antarctic Specially Managed Areas, this work assembles published datasets on phytoplankton biodiversity and ecology in confined coastal areas (embayments) of King George Island, WAP. Over 33 years (1980–2013), 415 species from 122 genera have been identified to species level, being mostly diatoms (371 species), with 10 new species described with local material (6 diatoms, 4 cyanobacteria). The importance of diatoms was indicated by the frequent occurrence of Corethron pennatum, Pseudogomphonema kamtshaticum, and abundant benthic genera in the plankton (e.g. Navicula, Cocconeis). The increased contribution of dinoflagellates after 2010 suggests marked changes in the water column. Early-summer blooms differ between the bays' eastern and western shores, with terrestrial melting and wind-driven upwelling inducing the dominance of benthic species at eastern shores, whereas planktonic diatoms (Thalassiosira, Pseudo-nizschia, and Chaetoceros) are most abundant along western shores and central areas. The importance of an accurate identification of organisms that are becoming key ecological components of the region is discussed, as recent changes in the microflora may affect the entire marine food web.

scholarly journals Evaluation of Various Environmental Factors on the Nutrient Uptake Competition between Nori Laver and Planktonic Diatoms in Ariake Bay, Japan

2005 ◽  
Vol 14 (3) ◽  
pp. 411-427 ◽  
Author(s):  
Osamu Kawaguchi ◽  
Tamiji Yamamoto ◽  
Osamu Matsuda ◽  
Toshiya Hashimoto
Keyword(s):  
Environmental Factors ◽  
Nutrient Uptake ◽  
Ariake Bay ◽  
Planktonic Diatoms

scholarly journals The perforation of the frustules of planktonic diatoms Pseudosolenia calcar-avis and Proboscia alata (Bacillariophyceae)

2019 ◽  
Vol 2 ◽  
pp. 19-26
Author(s):  
Lyakh A.M.
Keyword(s):  
Surface Area ◽  
Geometric Modeling ◽  
Direct Determination ◽  
Entire Surface ◽  
Planktonic Diatoms ◽  
Centric Diatoms ◽  
Flow Through ◽  
Material Energy ◽  
The Relationship

Physiological and biophysical characteristics of microalgae should strongly depend on the surface area of the cover of organisms, as all the material-energy streams flow through the surface. However, to determine the relationship between the intensity of the flow of substances with the physiology of unicellular, it is necessary to take into account only the area of perforations, since the rest of the shell is impermeable for substances. The direct determination of the area of perforations on the entire surface of the microalgae is very difficult. Therefore, the indirect method of estimating the perforation area using geometric modeling of the perforation distribution (texture) on the surface was used in this study. The object of the research is two types of marine plankton diatoms with large cylindrical frustules. It was assumed that the frustules are covered with a regular triangular texture of the areola. This texture can be divided into regular hexagons, which allows us to estimate the number of areolas as the ratio of the surface area of the frustules to the area of one hexagon. The model takes into account that each areola is covered with a silicon plate perforated by a smaller pore. The multiplication of the number of areolas on the area of a given pore gives the value of the total area of perforations. Calculations showed that the perforation of the frustules of Proboscia alata was 4%, and Pseudosolenia calcar-avis – 6%. These are the first estimates of the perforation of the entire surface of the diatom frustules. The acquired data confirms the hypothesis that frustules of the most centric diatoms are covered by pores by about 5%, and the other surface is impervious to material flows.

Impact of climate change and industrialization on remote Lake Bolshoe Toko, Siberia 

2021 ◽  
Author(s):  
Boris K. Biskaborn ◽  
Biljana Narancic ◽  
Kathleen R. Stoof-Leichsenring ◽  
Lyudmila A. Pestryakova ◽  
Peter G. Appleby ◽  
...  
Keyword(s):  
Climate Change ◽  
Deep Water ◽  
Boreal Lakes ◽  
Sediment Geochemistry ◽  
Long Distance ◽  
Lake Ecosystems ◽  
Planktonic Diatoms ◽  
Recent Climate Change ◽  
Recent Climate ◽  
Remote Lake

&lt;p&gt;To test if recent climate change and pollution affected remote lake ecosystems without direct human influence, we used paleolimnological methods on lake sediments from a large, prestine, and deep lake in Yakutia, Russia. We compared diatoms and sediment-geochemistry from before and after the onset of industrialization in the mid-nineteenth century, at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko. We analyzed diatom species changes and geochemical changes including mercury concentrations. Chronologies were established using &lt;sup&gt;210&lt;/sup&gt;Pb and &lt;sup&gt;137&lt;/sup&gt;Cs revealing sedimentation rates between 0.018 and 0.033 cm y&lt;sup&gt;-1&lt;/sup&gt; at shallow- and deep-water sites, respectively. Increase in light planktonic diatoms (&lt;em&gt;Cyclotella&lt;/em&gt;) and decrease in heavily silicified euplanktonic &lt;em&gt;Aulacoseira&lt;/em&gt; through time at deep-water sites can be related to warming air temperatures and shorter periods of lake-ice cover, causing pronounced thermal stratification. Diatom beta diversity changed only significantly in shallow-water communities which can be related to the development of new habitats with macrophyte growth. Mercury concentrations increased by a factor of 1.6 as a result of atmospheric fallout. Increases in the chrysophyte &lt;em&gt;Mallomonas&lt;/em&gt; indicates a trend towards acidification. We conclude that also remote boreal lakes are susceptible to human-induced long-distance pollution and recent climate change.&lt;/p&gt;

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