scholarly journals Internal microbial zonation assists in the massive growth of marimo, a lake ball of Aegagropila linnaei in Lake Akan

2021 ◽  
Author(s):  
Ryosuke Nakai ◽  
Isamu Wakana ◽  
Hironori Niki
Keyword(s):  
Lake Sediments ◽  
Northern Hemisphere ◽  
Green Alga ◽  
Bacterial Communities ◽  
Layer Structure ◽  
Brackish Waters ◽  
Massive Growth ◽  
Sulphur Cycle ◽  
Sediment Particles

Marimo (lake ball) is an uncommon ball-like aggregation of the green alga, Aegagropila linnaei1. Although A. linnaei is broadly distributed in fresh and brackish waters in the northern hemisphere, marimo colonies are found only in particular habitats. The colonies have been gradually shrinking in recent years. Nevertheless, it is not clear how and why A. linnaei forms such massive spherical aggregations. Here, we report the bacterial microbiomes inside various sizes and aggregating structures of natural marimo collected from Lake Akan, Japan. We observed multi-layers composed of sediment particles only in the sizeable radial-type marimo with a >20 cm diameter, not in the tangled-type marimo. The deeper layers were enriched by Nitrospira, potential novel sulphur-oxidizing bacteria, and sulphate-reducing Desulfobacteraceae bacteria. The sulphur cycle-related bacteria are unique to Lake Akan due to sulphur deposits from the nearby volcanic mountains. Some of them were also recovered from lake sediments. Microorganisms of the multi-layers would form biofilms incorporating nearby sediment, which would function as microbial seals within large radial-type marimo. We propose that the layer structure provides habitats for diverse bacterial communities, promotes airtightness of the marimo, and finally contributes to the massive growth of the aggregation. These findings provide a clue to deciphering the massive growth of endangered marimo aggregates.

Comparison of phosphorus fraction in eutrophic lake sediments from the northern hemisphere

2019 ◽  
Vol 36 (2) ◽  
pp. 100-121
Author(s):  
Lidong Huang ◽  
Ruiyao Sheng ◽  
Zhenxuan Li ◽  
Daquan Sun ◽  
Ning Yan
Keyword(s):  
Lake Sediments ◽  
Northern Hemisphere ◽  
Eutrophic Lake ◽  
Phosphorus Fraction

scholarly journals First record of the freshwater green alga Scotinosphaera austriaca from the Baltic Sea

2018 ◽  
Vol 63 (2) ◽  
pp. 65-67
Author(s):  
Marek Klin ◽  
Zuzanna Kowalska ◽  
Filip Pniewski ◽  
Adam Latała
Keyword(s):  
Baltic Sea ◽  
Green Alga ◽  
Genetic Data ◽  
First Record ◽  
Morphological Characters ◽  
The Baltic Sea ◽  
Brackish Waters ◽  
Green Microalga ◽  
Taxonomic Affiliation ◽  
The Baltic

AbstractThe freshwater green microalga Scotinosphaera austriaca has been recorded from the brackish waters of the Gulf of Gdańsk (Baltic Sea). Morphological characters and genetic data were analyzed to confirm the taxonomic affiliation. This species bears features unusual in representatives of Ulvophyceae present in the Baltic Sea.

scholarly journals Bacterial communities in trace metal contaminated lake sediments are dominated by endospore-forming bacteria

2013 ◽  
Vol 76 (S1) ◽  
pp. 33-46 ◽  
Author(s):  
Loïc Sauvain ◽  
Matthieu Bueche ◽  
Thomas Junier ◽  
Matthieu Masson ◽  
Tina Wunderlin ◽  
...  
Keyword(s):  
Trace Metal ◽  
Lake Sediments ◽  
Bacterial Communities

scholarly journals Functional biogeography and host specificity of bacterial communities associated with the Marine Green Alga Ulva spp.

2018 ◽  
Vol 27 (8) ◽  
pp. 1952-1965 ◽  
Author(s):  
Alexandra J. Roth-Schulze ◽  
José Pintado ◽  
Enrique Zozaya-Valdés ◽  
Javier Cremades ◽  
Patricia Ruiz ◽  
...  
Keyword(s):  
Host Specificity ◽  
Green Alga ◽  
Bacterial Communities ◽  
Marine Green Alga

Alpha-Effect, Current and Kinetic Helicities for Magnetically Driven Turbulence, and Solar Dynamo

2000 ◽  
Vol 179 ◽  
pp. 387-388
Author(s):  
Gaetano Belvedere ◽  
V. V. Pipin ◽  
G. Rüdiger
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Convection Zone ◽  
Solar Surface ◽  
Momentum Transport ◽  
Angular Momentum Transport ◽  
Magnetic Buoyancy ◽  
Alpha Effect ◽  
Current Helicity

Extended AbstractRecent numerical simulations lead to the result that turbulence is much more magnetically driven than believed. In particular the role ofmagnetic buoyancyappears quite important for the generation ofα-effect and angular momentum transport (Brandenburg & Schmitt 1998). We present results obtained for a turbulence field driven by a (given) Lorentz force in a non-stratified but rotating convection zone. The main result confirms the numerical findings of Brandenburg & Schmitt that in the northern hemisphere theα-effect and the kinetic helicityℋkin= 〈u′ · rotu′〉 are positive (and negative in the northern hemisphere), this being just opposite to what occurs for the current helicityℋcurr= 〈j′ ·B′〉, which is negative in the northern hemisphere (and positive in the southern hemisphere). There has been an increasing number of papers presenting observations of current helicity at the solar surface, all showing that it isnegativein the northern hemisphere and positive in the southern hemisphere (see Rüdigeret al. 2000, also for a review).

The Hemispheric Sign Rule of Current Helicity during the Rising Phase of Cycle 23

2000 ◽  
Vol 179 ◽  
pp. 303-306
Author(s):  
S. D. Bao ◽  
G. X. Ai ◽  
H. Q. Zhang
Keyword(s):  
Solar Cycle ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Active Regions ◽  
Hemispheric Preference ◽  
Current Helicity

AbstractWe compute the signs of two different current helicity parameters (i.e., αbestandHc) for 87 active regions during the rise of cycle 23. The results indicate that 59% of the active regions in the northern hemisphere have negative αbestand 65% in the southern hemisphere have positive. This is consistent with that of the cycle 22. However, the helicity parameterHcshows a weaker opposite hemispheric preference in the new solar cycle. Possible reasons are discussed.

Status of “AGK4” Project

1978 ◽  
Vol 48 ◽  
pp. 527-533
Author(s):  
Chr. de Vegt
Keyword(s):  
Northern Hemisphere ◽  
Proper Motion ◽  
The Mean ◽  
Spectral Bandpass

The present accuracy limit for the majority of fainter stars on the northern hemisphere is set by the AGK2/3-catalogue, recently completely finished, but it should be noted that its epoch is much earlier (1960). Furtheron the AGK3-catalogue is a direct repetition of the AGK2, the plates have been taken with the same astrograph in a broad blue spectral bandpass and measured visually with the same equipment, therefore virtually an instrumental standard of 1930 is realized again. Figure 1 shows the mean errors of the AGK2/3 catalogue positions as a function of magnitude. The best accuracy for the AGK2/3 data is obtained for the stars of about ninth magnitude: 017 (AGK2) and 020 (AGK3) but decreases for the faint stars with mpg11 to 019 (AGK2) and Pg 027 (AGK3). Here the AGK3 data are even less accurate. With increasing distance to the catalogue epochs, the accuracy of positions decreases due to the proper motion errors. In the upper part of figure 2 the dependence of the AGK2/3 catalogue accuracy on time is shown for the faint stars separately and an averaged value.

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