Actualistic Taphonomy of Freshwater Diatoms: Implications for the Interpretation of the Holocene Record in Pampean Shallow Lakes

Author(s):  
Gabriela S. Hassan ◽  
Claudio G. De Francesco ◽  
Marisel C. Díaz
Hydrobiologia ◽  
2017 ◽  
Vol 816 (1) ◽  
pp. 91-105 ◽  
Author(s):  
Ana Torremorell ◽  
María del Carmen Diéguez ◽  
Claudia Queimaliños ◽  
Irina Izaguirre ◽  
Horacio E. Zagarese

2017 ◽  
Vol 87 ◽  
pp. 99-111 ◽  
Author(s):  
Alessandro Amorosi ◽  
Luigi Bruno ◽  
Bruno Campo ◽  
Agnese Morelli ◽  
Veronica Rossi ◽  
...  

2021 ◽  
Author(s):  
Hugh Genoways

A survey of the archeological and paleontological literature allowed a compilation of Holocene records of mammals in Nebraska. This survey identified Holocene records from 338 sites in 62 of the 93 Nebraska counties. These counties were located throughout state, but there was a concentration of sites in southwestern Nebraska where there were 27 fossil sites in Frontier County and 22 in Harlan County. Fossils sites were underrepresented in the Sand Hills region. Records of fossil mammals covered the entire Holocene period from 13,000 years ago until AD 1850. A minimum of 57 species (with eight additional species potentially present) representing six orders of mammals were represented in the compilation—four species of Lagomorpha, four species of Soricomorpha, 17 species of Carnivora (with three additional species potentially present), one species of Perissodactyla, six species of Artiodactyla, and 25 species of Rodentia (with five additional species potentially present). The remains of bison were found at 276 sites, which was more than for any other species in the state. Additional species that formed the main portion of the diet of Native Americans were the next most abundant in the fossil record—deer, pronghorn, and wapiti. That these food species dominated in the Holocene record was to be expected because fossils were recovered primarily from archeological sites.


The Holocene ◽  
2012 ◽  
Vol 22 (12) ◽  
pp. 1461-1471 ◽  
Author(s):  
C Giraudi

The stratigraphic study of the Stagno di Maccarese, carried out on the sediments exposed in about 7 km of trenches excavated in an area of approximately 1.5 km2, has shown that in the course of the Holocene many environmental variations have taken place. The complex evolution of the marsh is demonstrated by the variations in water salinity and the presence of erosion surfaces and soils between the sediments. In the early Holocene, the area studied was an isolated marsh with water having variable salinity, and it was only about 6000 cal. yr BP that it was encompassed in the system of inner delta marshes. In the delta environment, the water of the marsh was oligohaline until about 9th–8th centuries bc, brackish from 9th–8th centuries bc to about 600 yr BP, and later oligohaline until the 19th century drainage. A number of environmental variations are connected with local phenomena, such as erosion of the beach ridges and Tiber floods, but the others can be correlated chronologically with climatic events recorded at regional and global scale. The millennial variations seem to be connected with changes in insolation, while abrupt variations can be correlated chronologically with the IRD events dated at 8200, 5900, 4200, 2800, 1400 and 500 cal. yr BP.


2006 ◽  
Vol 228 (1-4) ◽  
pp. 55-71 ◽  
Author(s):  
N. Nørgaard-Pedersen ◽  
W.E.N. Austin ◽  
J.A. Howe ◽  
T. Shimmield

2020 ◽  
Vol 96 (11) ◽  
Author(s):  
M R Schiaffino ◽  
P Huber ◽  
M Sagua ◽  
C A Sabio y García ◽  
M Reissig

ABSTRACT The aim of this work was to assess the temporal patterns in the community composition of phytoplankton (PCC) and bacterioplankton (BCC) in two interconnected and hypertrophic Pampean shallow lakes in Argentina. Factors shaping their community dynamics and community temporal covariations were also analysed. We performed 4 years of seasonal samplings (2012–2016) and communities were studied by the Utermöhl approach (PCC) and Illumina MiSeq sequencing (BCC). We found marked seasonal variations in both communities and inter-annual variations with decreasing microbial community similarities during the study. We also observed covariation in community-level dynamics among PCC and BCC within and between shallow lakes. The within-lake covariations remained positive and significant, while controlling for the effects of intrinsic (environmental) and extrinsic (temporal and meteorological) factors, suggesting a community coupling mediated by intrinsic biotic interactions. Algal-bacterial associations between different taxa of phytoplankton and bacterioplankton within each lake were also found. PCC was mainly explained by pure regional extrinsic (17–21%) and intrinsic environmental (8–9%) factors, while BCC was explained by environmental (8–10%) and biotic interactions with phytoplankton (7–8%). Our results reveal that the influence of extrinsic regional factors can be channeled to bacterioplankton through both environmental (i.e. water temperature) and phytoplankton effects.


Hydrobiologia ◽  
2019 ◽  
Vol 830 (1) ◽  
pp. 255-276 ◽  
Author(s):  
M. R. Schiaffino ◽  
N. Diovisalvi ◽  
D. Marfetán Molina ◽  
P. Fermani ◽  
C. Li Puma ◽  
...  

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