Abstract Ice-free areas of Antarctica represent an important study region that helps us understand how human activity affects plant communities and soil properties. The goal of this study was to determine the changes in plant composition and soil properties around a whale bone skeleton (WB) near Ferraz Station, King George Island, Antarctica from 1972 to 2020 (48 years). The WB was assembled in 1972 by Jacques-Yves Cousteau and his team. It is located in a large moss field and visited by many tourists. We studied the plant composition and development based on historical and recent photographs and phytosociological studies from 1986 to 2020. The soil was sampled in February 2009 to determine general properties. The results showed that human activity surrounding the WB directly affected the plant community composition and soil properties. The Syntrichia cushions were positively affected by the calcium deposits from bone dissolution. The principal component analysis revealed that mineralization of the bones increased soil nutrient assembly. A strong phosphatization process was observed in the WB area, similar to that in ornithogenic soils. The WB on the marine terrace enhanced soil fertility and changed the plant community.

Abstract Southern giant petrels (Macronectes giganteus) are found in the Antarctic. They build their nests with rock fragments, disturbing large areas during incubation and chick feeding periods; however, their impact on vegetation is unknown. Thus, we aimed to evaluate the effect of Petrel nests and associated breeding activities on the diversity and structure of cryptogam communities of Stinker Point, Elephant Island. We selected 13 nests in February and March 2012 and continue the monitoring in 2018. The area of direct influence of breeding activities was photographed to calculate plant community coverage. The results demonstrated that species richness, community coverage and composition, and beta diversity showed significant differences between active and inactive nests. The linear mixed-effect models revealed that the positive effect of nest area mainly caused variation in community coverage, but had a negative effect on beta diversity. Sphaerophorus globosus (lichen) grew around the inactive nests, sometimes forming a ring up to 1 m in diameter. This ring was then surrounded by the Chorisodontium acyphyllum moss colonized by S. globosus, and a final ring of Sanionia uncinata, colonized by the same lichen. Recently constructed nests are generally surrounded by Prasiola crispa and Sanionia uncinata carpets.

RESUMO Este estudo avaliou a memória de reconhecimento e os níveis de danos no DNA (sangue e hipocampo) em ratos Wistar jovens desnutridos. O experimento foi conduzido ao longo de 14 semanas com os animais divididos em grupo controle (GC, n=8) e grupo desnutrido (GD, n=12) que foi submetido a restrição calórica. O estado nutricional para desnutrição foi definido pelo Índice de Massa Corporal (IMC) de ≤0,45g/cm2 e pela pesagem dos órgãos/tecido (fígado, baço, intestino, gordura peritoneal, rim e encéfalo). O Teste de Reconhecimento de Objeto Novo avaliou a memória de reconhecimento e o Ensaio Cometa avaliou os níveis de danos no DNA. O teste t de Student, ANOVA de duas vias e a análise de correlação de Pearson foram usados e o nível de significância foi de p<0,05. O GD apresentou um menor IMC e menores pesos dos órgãos/tecido que o GC (p<0,001). Em relação à memória de curto prazo, a taxa de reconhecimento foi maior no GD (p<0,05), apenas após 4 semanas. Em relação à memória de longo prazo, novamente a taxa de reconhecimento foi maior no GD em comparação ao GC, depois de 4 semanas (p<0,001) e depois de 14 semanas (p<0,01). O GD apresentou diminuição dos níveis de danos no DNA no sangue (p<0,01) e aumento nos níveis de danos no DNA no hipocampo (p<0,01). Concluiu-se neste estudo que a desnutrição pela restrição calórica não causou prejuízo na memória de reconhecimento, porém induziu danos no DNA no hipocampo.

ABSTRACT This study evaluated the recognition memory and the levels of DNA damage (blood and hippocampus) in undernourished young Wistar rats. The experiment was conducted along 14-week with rodents divided in control group (CG, n=8) and undernourished group (UG, n=12) which was submitted to caloric restriction. Nutritional status for undernutrition was defined by Body Mass Index (BMI) ≤0.45g/cm2 and by weighting the organs/tissue (liver, spleen, intestine, peritoneal fat, kidney and encephalon). The Novel Object Recognition Test assessed recognition memory and the Comet Assay evaluated the levels of DNA damage. Student t test, 2-way ANOVA and Pearson's correlation analysis were used and the significance level was of p<0.05. The UG showed lower BMI and organ/tissue weights than CG (p<0.001). In short-term memory, the recognition rate was higher in the UG (p<0.05), only after 4 weeks. In the long-term memory, again recognition rate was higher in the UG than the CG, after 4 weeks (p<0.001) and 14 weeks (p<0.01). The UG showed decreased levels of DNA damage in the blood (p<0.01) and increased levels in the hippocampus (p<0.01). We concluded in this study that the undernutrition by caloric restriction did not cause impairment in recognition memory, however induced DNA damage in the hippocampus.