71 research outputs found
Debarya glyptosperma (De Bary) Wittrock 1872 (Zygnemataceae, Chlorophyta) as a possible airborne alga : a contribution to its palaeoeocological interpretation
This paper reports the fi nding of Debarya glyptosperma zygospores in xeric grasslands far from the natural habitat of algal species. This fact suggests that this species is an airborne alga and this has not been reported before. What is more the discoidal shape of the zygospores may dispose this taxon among the Zygnemataceae family towards air dispersion. This new information may assist in assessing it as an indicator of limnic conditions. However, the simple discovery of Debarya without any accompanying algal taxa and/or other water plants should not be conclusively interpreted as proof of the existence of water bodies because the zygospores might originate from distant transport
Exploring extreme brightness variations in blue supergiant MACHO 80.7443.1718: Evidence for companion-driven enhanced mass loss
Evolution of massive stars is dominated by interactions within binary
systems. Therefore, it is necessary to investigate all forms of interaction in
binary systems that may affect the evolution of the components. One of such
`laboratories' is the massive eccentric binary system MACHO80.7443.1718
(ExtEV). We examine whether the light variability of the ExtEV can be explained
by a wind-wind collision (WWC) binary system model. We conducted an analysis of
broadband multi-color photometry of ExtEV, time-series space photometry from
TESS, ground-based Johnson photometry, and time-series spectroscopy. We
fitted an analytical model of light variations to the TESS light curve of
ExtEV. We rule out the possibility of the presence of a disk around the primary
component. We also argue that the non-linear wave-breaking scenario is not
consistent with the observations of ExtEV. We refine the orbital parameters of
ExtEV and find evidence for the presence of a tertiary component. Using
evolutionary models we demonstrate that the primary component's mass is between
25 and 45M. We successfully reproduce light curve of ExtEV with our
model, showing that the dominant processes shaping its light curve are
atmospheric eclipse and light scattered in the WWC cone. We also estimate the
primary's mass-loss rate due to stellar wind for M. ExtEV is not an extreme eccentric
ellipsoidal variable, but an exceptional WWC binary system. The mass loss rate
we derived exceeds theoretical predictions by up to two orders of magnitude.
This implies that the wind in the system is likely enhanced by tidal
interactions, rotation, and possibly also tidally excited oscillations. ExtEV
represents a rare evolutionary phase of a binary system that may help to
understand the role of a companion-driven enhanced mass loss in the evolution
of massive binary systems.Comment: Submitted to Astronomy&Astrophysics, 23 pages, 15 figures, 9 table
Kettle-hole peatlands as carbon hot spots : Unveiling controls of carbon accumulation rates during the last two millennia
Funding Information: We would like to thank the anonymous reviewers for their comments that helped us to improve the manuscript. The research was funded by the National Science Centre (Poland), grant 2015/17/B/ST10/01656.Peer reviewe
Neodymium isotopes in peat reveal past local environmental disturbances
Funding The Stawek profile radiocarbon dating and investigation and neodymium measurements were financed by the National Science Centre, Poland, grants no. 2019/03/X/ST10/00849 and 2020/39/D/ST10/00641. The Głęboczek profile radiocarbon dating and investigation were financed by the National Science Centre, Poland, grant no. 2015/17/B/ST10/01656.Peer reviewedPublisher PD
Znaczenie wspólnych badań historycznych i paleoekologicznych nad wpływem człowieka na środowisko. Przykład ze stanowiska Kazanie we wschodniej Wielkopolsce
The aim of the article is to present the potential of interdisciplinary research on the human impact on the environment in the past on the example of a site in Greater Poland (Wielkopolska). It uses high-resolution palaeoecological analyses of peat archives from the Kazanie peat bog as well as archaeological and historical materials reflecting the settlement and economic activity of the inhabitants of Pobiedziska and surrounding villages throughout last 1200 years.Celem artykułu jest przedstawienie potencjału interdyscyplinarnych badań nad wpływem człowieka na środowisko w przeszłości na przykładzie Wielkopolski. Zostaną w nim wykorzystane wysokorozdzielcze analizy paleoekologiczne źródeł przyrodniczych wydobytych z torfowiska Kazanie oraz materiały archeologiczne i historyczne obrazujące osadnictwo i aktywność gospodarczą mieszkańców Pobiedzisk i okolicznych wsi w ciągu ostatnich 1200 lat
Znaczenie wysokorozdzielczych wielowskaźnikowych (multi-proxy) badań paleoekologicznych dla geografii historycznej i historii gospodarczej
The article presents the importance of palaeoecology for the study of economic history, historical geography and environmental history. The text introduces the methodological possibilities of palaeoecology. We pay attention to the unused potential of high resolution palaeoecology. By using natural archives (sediments of lakes and peatlands), we are able to trace the history of changes in nature. We can reconstruct history and better understand the changes in Poland’s ecosystems and its economic development.Artykuł prezentuje znaczenie paleoekologii dla badań historii gospodarczej, geografii historycznej i historii środowiskowej. Praca przybliża możliwości metodyczne paleoekologii. Zwracamy uwagę na niewykorzystany dotąd potencjał wysokorozdzielczej paleoekologii. Wykorzystując naturalne archiwa (osady jezior i torfowisk), jesteśmy w stanie prześledzić historię przemian przyrody, możemy zrekonstruować historię i lepiej zrozumieć zmiany ekosystemów Polski oraz jej rozwój ekonomiczny
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