profundal zone
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Palaios ◽  
2020 ◽  
Vol 35 (8) ◽  
pp. 317-326
Author(s):  
KATARÍNA HOLCOVÁ ◽  
VLADIMÍR SUCHÁNEK ◽  
ZUZANA HEŘMANOVÁ ◽  
DANIEL VONDRÁK

ABSTRACT Microbioerosion structures are a common sign of microbial activity known mainly from marine environments and calcareous substrates, or from pollen records. However, the same phenomenon has been overlooked in animal fossils preserved in lake sediments. We studied 430 fragments of chitinous microfossils from three central European glacial lakes and detected microboring structures in approximately 10%. The microfossils belong to two size groups: (1) spherical objects with lengths ranging from 50 to 300 μm that are probably microturbelarian (Turbellaria: Rhabdocoela) cocoons, and (2) larger remnants (up to 2 mm long) of caddisfly (Insecta: Trichoptera) frontoclypeal apotomes. Four microbioerosion morphotypes were distinguished: (1) small holes (< 0.6 μm) oriented perpendicular to microfossil walls, likely produced by bacteria or fungi; (2) simple meandering tunnels and; (3) asterisk-like tunnel structures produced by fungi and/or fungus-like organisms; and (4) abrasions caused by biofilms. The maximum diameter of the simple holes and both tunnel structures depended on host-microfossil size: a higher diversity of microbioerosions was found on larger chitinous fragments. We propose that the good preservation of microfossils in the studied sediment samples might be due to rapid transport to the anoxic profundal zone or by rapid burial in anoxic sediments.


Hydrobiologia ◽  
2020 ◽  
Vol 847 (21) ◽  
pp. 4425-4446 ◽  
Author(s):  
Marc Beutel ◽  
Byran Fuhrmann ◽  
Goldamer Herbon ◽  
Alex Chow ◽  
Sarah Brower ◽  
...  

Author(s):  
Katarzyna Kowalczewska-Madura ◽  
Renata Dondajewska ◽  
Ryszard Gołdyn ◽  
Joanna Rosińska ◽  
Stanisław Podsiadłowski

The urban Swarzędzkie Lake, into which sewage had been diverted many years ago, was still characterised by low ecological status. Three restoration methods were used in order to improve the water quality, i.e. aeration of the waters overlying the bottom sediments, inactivation of phosphorus in the water column with iron sulphate and magnesium chloride and biomanipulation with pike stocking. The aim of the research was to define seasonal and spatial changes of phosphorus internal loading from bottom sediments and to compare this with previous years. We also considered changes in the process of P release when the restoration treatments were limited after 3 yr from 3 methods to 1 method. The highest phosphorus release from bottom sediments was found in the profundal zone, where in summer periods it would reach up to 29.2 mgP m−2 day−1. The lowest P release was observed in the littoral zone, down to a depth of 3 m, where it did not exceed 10.0 mgP m−2 day−1. 31% of the whole load of P released from the bottom sediments was originated from this zone. The research showed an increase of phosphorus release in the first years of restoration treatment and a systematic decrease at all stations in the following years.


2016 ◽  
Vol 16 (1) ◽  
pp. 15-26 ◽  
Author(s):  
Izabela Bojakowska

AbstractIn 2010-2013, 528 samples of surface sediments were collected from the profundal zone of lakes to determine concentrations of phosphorus, Al, Ca, Fe, K, Mn, Na and S, as well as trace elements (As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sn, Sr, Ti, V and Zn) using the ICP-OES method. Additionally, Hg concentration (by the TMA method) and organic carbon concentration (using the coulometric titration method) were also determined. Phosphorus concentration was found to range from 0.005 to 1.925% (0.109% on average). High phosphorus concentrations in sediments were reported in lakes located within and around urban areas, in lakes on which recreation centres and leisure facilities are situated, and in lakes adjoining special protection areas of birds. The phosphorus concentration in sediments shows a clear correlation with the contents of Al, Fe, Mn, S and TOC, which indicates the presence of phosphorus in both organic and inorganic forms. It also correlates with the contents of most of the trace elements examined for this study, including Zn, Hg and Pb. A certain regional variability was found; water sediments of lakes in the Masurian and Pomeranian lakelands, located in the area covered by the Pomeranian phase ice sheet, are characterised by a slightly higher phosphorus concentration compared with those from the Greater Poland Lakeland situated in the area of the Poznań phase glaciation.


2012 ◽  
Vol 12 (4) ◽  
pp. 207-212 ◽  
Author(s):  
Daniel Szymański ◽  
Julita Dunalska ◽  
Michał Łopata ◽  
Izabela Bigaj ◽  
Rafał Zieliński

AbstractThe aim of this study was to determine the chemical composition of Lake Widryńskie bottom sediments (max. depth. 27.0 m, area 123.9 ha). The sampling of bottom sediments was conducted once, on 16 August 2010. Sampling was made in 10 specific areas. Among the 10 samples, 4 samples were taken from the littoral and sublittoral zones, while the rest were taken from the profundal zone. The dominant component of the sediments was silica and calcium carbonates were subdominant. Based on the survey, it was determined that silica occurred in greater numbers in littoral sediments, while in sublittoral sediments there was increased participation in the chemical composition of organic matter. The elements that build a capacity complex were a small percentage of the dry weight of sediment. Sediment from the vicinity of inflows contains higher amounts of silica, which confirmed the impact of the catchment on the chemical composition of sediments.


2008 ◽  
Vol 11 (4) ◽  
pp. 368-376 ◽  
Author(s):  
Maureen G. Walsh ◽  
Robert O'Gorman ◽  
Theodore Strang ◽  
William H. Edwards ◽  
Lars G. Rudstam

Biologia ◽  
2006 ◽  
Vol 61 (18) ◽  
Author(s):  
Jolana Tátosová ◽  
Evžen Stuchlík

AbstractThe profundal community of L’adové pleso (an oligotrophic high mountain seepage lake at an altitude of 2,057 m with a max. depth of 18 m and an ice-cover period from October–July) was studied from December 2000–October 2001. Chironomidae, the most significant part of the studied community, are represented by four taxa and dominated by Micropsectra radialis Goetghebuer, 1939 and Pseudodiamesa nivosa (Goethgebuer, 1928). These two species showed a 1-year life cycle. The total densities of chironomids varied from 0 to 5,927 ind. m−2; no chironomids, or very low densities, were found during the winter/spring period, probably due to low oxygen concentrations in the medial part of the lake. These low oxygen concentrations probably caused the relocation of larvae from the medial part of the sedimentary area at the same time.


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