Middle Holocene marine and land-tetrapod biodiversity recovered from Galeão shell mound, Guanabara Bay, Brazil

Author(s):  
Mariana Samor Lopes ◽  
Sandrine Grouard ◽  
Maria Dulce Gaspar ◽  
Elisamara Sabadini-Santos ◽  
Salvador Bailon ◽  
...  
Author(s):  
Ksenya V. Poleshchuk ◽  
Zinaida V. Pushina ◽  
Sergey R. Verkulich

The diatom analysis results of sediment samples from Dunderbukta area (Wedel Jarlsberg Land, West Svalbard) are presented in this paper. The diatom flora consists of four ecological groups, which ratio indicates three ecological zones. These zones show environmental changes of the area in early–middle Holocene that is demonstrating periods of regression and temperature trends.


GEOgraphia ◽  
2010 ◽  
Vol 8 (16) ◽  
Author(s):  
Miguel Ângelo Ribeiro

O objetivo que permeia a presente pesquisa é utilizar a Fortaleza de Santa Cruz, localizada no bairro de Jurujuba, em Niterói, construída em 1555, na entrada da barra da Baía de Guanabara, como foco de antílise, ressaltando a importância deste fixo social enquanto atração turística e de lazer, incluindo a cidade de Niterói no circuito destas atividades, complementares à cidade do Rio de Janeiro; além de abordar conceitos e categorias analíticas, oriundos das ciências sociais, principalmente provenientes da Geografia, pertinentes ao estudo das atividades em tela. Neste contexto, na dinâmica espacial da cidade de Niterói, o processo de mudança de função dos fixos sociais têm sido extraordinário. Residencias unifamiliares, prédios e até mesmo fortificações militares, verdadeiras monumentalidades, foram refuncionalizadas, passando por um processo de turistificação. Assim, a refuncionalização da respectiva Fortaleza em espaço cultural toma-se um importante atrativo da história, do patrimônio, da cultura, marcando no espaço urbano sua expressões e monumentalidade, criada pelo homem como símbolo de seus ideais, objetivos e atos, constituindo-se em um legado as gerações futuras, formando um elo entre passado, presente e futuro. Abstract This paper focuses on Santa Cruz Fortress, built in 1555 in Jurujuba (Niterói), to guard the entrance of Guanabara bay, and stresses its role as a towist attraction and leisure' area, as a social fix which links the city of Niterói to the complementary circuit of these activities in the city of Rio de Janeiro. The study uses important concepts and analytic categories fiom social sciences, particularly fiom Geography.In the spatial dynamic of the city of Niterói, change in functions of social fuces has been extraordinary. Single-family dwellings, buildings and even military installations have been re-functionalized, undergoing a process of touristification. In that way, the refunctionalization of the Fortress as a cultural space provides an important attraction in the domains of history, patrimony, and culture, providing the urban space with an expression of monumentality, created by man as a symbol of his ideals, aims and actions, a legacy to future generations forming a link between past, present and future.


2021 ◽  
Vol 41 (3) ◽  
Author(s):  
R. C. Cordeiro ◽  
D. D. dos Santos ◽  
R. E. Santelli ◽  
A. G. Figueiredo ◽  
L. S. Moreira ◽  
...  

2020 ◽  
Vol 11 (1) ◽  
pp. 230
Author(s):  
Hoil Lee ◽  
Jin-Young Lee ◽  
Seungwon Shin

We obtained a 15 m drill core from Deukryang Bay on the southwest coast of Korea, which is now an area of reclaimed land used for agriculture. We investigated changes in the depositional environment and hydrological climate responses to sea level changes using sedimentary facies, radiocarbon ages, grain-size analysis, total organic carbon (TOC), total sulfur (TS), and stable carbon isotopes (δ13C). Sediment deposition began at 12,000 cal yr BP and was divided into four stages based on changes from fluvial to intertidal environments related to Holocene marine transgression events. Stage 1 (>10,000 cal yr BP) is represented by fluvial sediments; Stage 2 (10,000–7080 cal yr BP) is represented by the deposition of mud facies in an intertidal zone in response to sea level rise; Stage 3 (7080–3300 cal yr BP) was a period of gradually descending sea level following the Holocene maximum sea level and is characterized by gradual changes in TOC, TS, and C/S ratios compared with the mud facies of Stage 2. Stage 4 (3300 to present) was deposited in a supratidal zone and contains low TS and an abundance of TOC. Based on our TS and C/S ratio results, the south coast of Korea was mainly affected by sea level rise between 7000 and 3000 cal yr BP, during the middle Holocene. At 3000 cal yr BP, sea level began to stabilize or gradually decrease. In addition, changes in δ13C values are clearly observed since ca. 5000 cal yr BP, in particular, large hydrological changes via freshwater input are confirmed in 4000–3000 cal yr BP. We consider these shifts in freshwater input indicators of an increased influence of El Niño and La Niña conditions, related to the weakening of the East Asian Summer Monsoon (EASM) and changes in sea surface temperature (SST) of the Western Pacific Ocean during the middle Holocene climatic optimum (between 7800 and 5000 cal yr BP). The cooling periods of SST in East Asia between 8400 and 6600 cal yr BP reported from the west coast of Korea are related closely to changes in vegetation (as evidenced by δ13C) from 7700 cal yrs BP to the present in the southwest coast of Korea. We interpret the freshwater input events at 4000–3000 cal yr BP to be related to changes in SST in response to the weakening of the EASM on the southwest coast of Korea. However, additional research is needed to study the southward migration effect of the westerly jet related to SST and atmospheric circulation controlling terrestrial climate in the middle Holocene.


2021 ◽  
pp. 1-8
Author(s):  
Thaísa Araújo ◽  
Helena Machado ◽  
Dimila Mothé ◽  
Leonardo dos Santos Avilla

Abstract Climatic and environmental changes, as well as human action, have been cited as potential causes for the extinction of megafauna in South America at the end of the Pleistocene. Among megamammals lineages with Holarctic origin, only horses and proboscideans went extinct in South America during this period. This study aims to understand how the spatial extent of habitats suitable for Equus neogeus and Notiomastodon platensis changed between the last glacial maximum (LGM) and the middle Holocene in order to determine the impact that climatic and environmental changes had on these taxa. We used species distribution modeling to estimate their potential extent on the continent and found that both species occupied arid and semiarid open lands during the LGM, mainly in the Pampean region of Argentina, southern and northeastern Brazil, and parts of the Andes. However, when climate conditions changed from dry and cold during the LGM to humid and warm during the middle Holocene, the areas suitable for these taxa were reduced dramatically. These results support the hypothesis that climatic changes were a driving cause of extinction of these megamammals in South America, although we cannot rule out the impact of human actions or other potential causes for their extinction.


Author(s):  
Marcelo C. L. Cohen ◽  
Paloma Maria Pinto Camargo ◽  
Luiz C. R. Pessenda ◽  
Flávio Lima Lorente ◽  
Adriana V. De Souza ◽  
...  
Keyword(s):  

2020 ◽  
Vol 35 ◽  
pp. 101143
Author(s):  
Michele Fernandes ◽  
Estefan Monteiro da Fonseca ◽  
Leonardo da Silva Lima ◽  
Susanna Eleonora Sichel ◽  
Jessica de Freitas Delgado ◽  
...  

2005 ◽  
Vol 32 (10) ◽  
pp. 1481-1500 ◽  
Author(s):  
Andrzej Weber ◽  
Hugh G. McKenzie ◽  
Roelf Beukens ◽  
Olga I. Goriunova

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