The paleoecological evolution of a peat bog in the Campos region, Rio Grande do Sul State, Brazil, was determined based on an integrated study of stratigraphy, palynology, and geochronology. The peat bog is constituted of silty-clay material, with high levels of ash (residue on ignition) and organic matter content that was deposited on a sandy substrate. Palynological analysis show that grassland taxa dominated from the base of the core at the early deglacial (∼17.4 cal kyr B.P.) to the Present. Four pollen zones were identified: CCQ I Zone (3.20 m to 2.50 m), covering the deglaciation (Upper Pleistocene), corresponding to dry climate conditions; CCQ II Zone (2.50 m to 1.60 m, latest deglaciation and Early Holocene), associated with a slightly humid climate; CCQ III Zone (1.60 m to 0.50 m, mid to late Holocene), established under very humid climatic conditions; and CCQ IV Zone (0.50 m to 0.00 m, last ∼500 years), representative of a low-humidity period. The floristic composition of grassland communities observed throughout the drill core is very similar to that found in the region where the municipality of Cacequi is located, in which Poaceae, Asteraceae, Fabaceae, and Rubiaceae were identified as the most abundant families. Consequently, although in the last ∼17.4 cal kyr B.P. the humidity oscillated, the grassland vegetation remained predominant, although not being represented by the same families, as indicated by changes in the floristic composition among the four pollen zones. Palynological and geochronological data, when compared with other sectors of the Río de la Plata Grasslands, show a predominance of dry conditions over the studied interval. From the early deglacial until the Present, climatic fluctuations shaped the diversity of plant communities and affected the particularities of each sector of the Río de la Plata Grasslands, including the Campos region. High ash content was detected along the core, similar to what occurs with other peatlands already studied in Brazil. In the peat bog analyzed, Poaceae is the predominant family, being known as a major producer of biomineralized structures, which would explain the high ash content recorded.

This study aimed to quantify marine litter before and during the COVID pandemic found on urban touristic beaches closed to beachgoer access in northeastern Brazil. Litter identification and quantification was conducted during April, June, and August 2019, when 3583 items were sampled, and replicated during the same months in 2020, when access to the beaches studied was prohibited and a significant reduction in the amount of litter was found, 1812 items (49% decrease). Transects were used to monitor and classify litter according to its source, namely: autochthonous (litter that was locally discarded) and allochthonous (litter from other sites and sources). All beaches were classified as “very clean” and presented a smaller amount of litter during the beach closure period. The highest total marine litter reduction between the periods studied was 83%, while autochthonous litter in particular showed the most significant reduction, 88%. The comparison between the quantity and type of litter found in both periods showed greater specific anthropic pressure from beach users.

The fossil molluscan assemblages found on the shores of Mirim Lake, in southern Brazil and Uruguay, provide information about the environmental changes and geological evolution of that water body. The storm-generated shell deposits at Latinos Spit on the Brazilian shore are dominated by the estuarine bivalve Erodona mactroides, represented mostly by juveniles, and the gastropod Heleobia australis. Species previously unrecorded in this site include the marine gastropods Cylichnella bidentata, Buccinanops cochlidium and Pachycymbiola brasiliana, and the bivalves Tagelus plebeius, Ostrea puelchana, Crassostrea cf. praia, Mactra isabelleana, Anomalocardia flexuosa and Cyrtopleura costata. The two latter currently inhabit tropical areas to the north of Rio Grande do Sul, and their presence in Mirim Lake indicates average coastal water temperatures about 2–3 °C warmer than today. This condition promoted the precipitation of calcium carbonate from dissolved shells, thus cementing together sand and shells in the form of coquinas. The stratigraphic succession, OSL ages obtained in quartz sand from one coquina, radiocarbon dated shells, and δ13C and δ18O of five E. mactroides and five marine species indicate that Mirim Lake became a brackish lagoon around 7.6 ka ago, in response to the postglacial marine transgression (PMT), followed by fully marine conditions during the sea-level highstand of 6–5 ka BP. Marine influence was reduced after ∼4 ka BP as the result of sea-level fall and the closure of the connection with the ocean, related to the evolution of the sandy barrier that originated the modern shoreline. The environmental changes recorded in Mirim Lake help understand how coastal lagoons and their associated ecosystems respond to sea-level oscillations, which may be relevant to address future responses of these water bodies to the ongoing climate change.