Giliane Gessica Rasbold

• PhD in Environmental Science
• Professor (Assistant) at Western Kentucky University

The environmental history of the central Pantanal wetlands of western Brazil is inferred for the last 19 kyrs based on a multi-indicator paleolimnological analysis of a sediment core from Lake Negra. The core, dated by 14C and OSL, shows variations in the abundance, diversity, and preservation of sponge spicules and phytoliths through time, consist...

We tested the use of phytoliths and seeds as bioindicators in the paleoenvironmental reconstruction of fluvial islands and compared the results with those of facies and pollen analyses. The studied material was taken from a 215 cm core drilled in Mutum Island. The study included a) the quantification and identification of phytoliths and seeds, b) t...

Cerrado vegetation is associated with the semi-humid climate of the Central Brazil highlands. The presence of this vegetation in small and sparse areas in Paraná, Southern Brazil, can be associated with its past climate conditions. Paleoenvironmental changes of Cerrado vegetation in the Campo Mourão region (24º06’S - 52º23’W) are discussed in this...

Cyperaceae plants are significant indicators for wet environments in paleoenvironmental studies. The characterization of modern phytoliths in Cyperaceae plants is fundamental for the identification and the taxonomic correlation with the morphologies preserved in sediments. This study proposes to expand the characterization and quantification of Cyp...

There are few studies on paleoenvironmental reconstruction using phytoliths found in sedimentary deposits. Most of the research involving these siliceous structures has been performed based mainly on soil profiles. However, the preservation of phytoliths in sedimentary deposits, especially in peat bogs, is preferred because the presence of natural...

Building resilience to climate change in the Afrotropics hinges on accurately predicting the style and tempo of ecosystem responses. Paleoecological records offer valuable insights into vegetation dynamics, yet high-resolution data sets remain scarce in Africa. Here, we present a new radiocarbon-dated sediment core from Lake Tanganyika, capturing t...

Middle and Late Holocene sediments have not been extensively sampled in Lake Tanganyika, and much remains unknown about the response of the Rift Valley’s largest lake to major environmental shifts during the Holocene, including the termination of the African Humid Period (AHP). Here, we present an integrated study (sedimentology, mineralogy, and ge...

River avulsions drive important changes in the Pantanal wetlands, owing to their role in the hydro-sedimentology of the region. Although relevant to numerous ecosystem services, few studies have analyzed the influence of river avulsions on soil fertility in the Pantanal. Here, we use the largest ongoing avulsion in the Taquari River (Caronal region...

The lower Nhecolândia region, in the south of the Pantanal, contains thousands of shallow freshwater and saline-alkaline lakes isolated by sandy ridges. To understand the paleoenvironment, sediment cores from B02SR (freshwater) and 07SR (saline-alkaline) lakes were analyzed, employing a combination of ¹⁴C dating, microfossils, geochemical, elementa...

Sedimentological processes are underexplored in retro-arc basin segments of source-to-sink systems, particularly in the distal back-bulge depozone. The extant Pantanal Basin of Latin America is a large sub-tropical continental back-bulge for which the boundary conditions on riverine sedimentation (tectonics, climate, phytogeography) are reasonably...

Freshwater sponges (Porifera: Spongillida) are sessile invertebrates with skeletons composed of siliceous elements termed spicules. Sponge spicules (megascleres, microscleres, and gemmuloscleres) are characterized by widely varying sizes and shapes. These spicules are well-preserved in lacustrine, wetland, and riverine sediments and hold significan...

Dam installation on a deep hydrologically open lake provides the experimental framework necessary to study the influence of outlet engineering and changing base levels on limnogeological processes. Here, high-resolution seismic reflection profiles, sediment cores, and historical water level elevation datasets were employed to assess the recent depo...

Shell mounds, or middens, are artificial accumulations of food remains such as shells, sediments, artefacts and remains from daily life and funerary rituals, which were deposited in our study area by groups of Sambaquian fisher-hunter-gatherers. These mounds contain remains, which are representative of the fauna and flora at the time they were form...

In the southern highlands of the Upper Paraguay River watershed, hundreds of small and shallow ponds exist, but little is known about their origins or potential to record hydroclimate signals in their sediments. Here, we present a multi-proxy evidence that reveals details about the paleolimnological evolution of these shallow tropical lakes. The av...

Shellmounds, or middens, are artificial accumulations constituted by food remains, sediments, artifacts, and vestiges of daily life and funerary rituals, and built by groups of fishermen-hunter-gatherers. These archaeological sites contain groups of organisms representative of the fauna and flora existing at the time they were formed, enabling the...

Skeletal remains of freshwater sponges are important microfossils that may be preserved in the sediments of inland waters. Yet, much is still unknown about the sponge fauna of the Nearctic, which limits their use in paleoenvironmental reconstructions. Here, we report the first evidence of an extant freshwater sponge fauna in Jackson Lake, Grand Tet...

Studies of lake sediments are valuable for evaluating ancient climatic changes and anthropogenic disturbances in tropical ecosystems. The combination of paleolimnological and archeological datasets from a common timeframe can reveal the complex relationships among climate, vegetation, and human history. Little is known about human activities and th...

Wetland carbon storage is an important and environmentally sensitive ecosystem service. Carbon burial in the floodplain lakes of the Pantanal (tropical South America) appears to have varied during the late Quaternary, but several paleolimno-logical studies have recorded unusually high sediment organic carbon content from * 7.3 to 6.0 cal kyr BP in...

This study aimed to test the use of inland sponge spicules as proxy data for a Holocene paleoenvironmental reconstruction of the Trairí River valley, in the state of Rio Grande do Norte, in Northeast of Brazil. Spicules were recovered from sediments from two core samples obtained in the Fumo and Urtiga lakes, for depths of 0.60 m and 0.96 m, respec...

Os sambaquis são sítios de pescadores-caçadores-coletores que contém conjuntos da fauna e flora existentes à época em que se formaram. O sambaqui sob rocha Casa de Pedra (São Francisco do Sul), em Santa Catarina, foi estudado a partir de análises de fitólitos para interpretar aspectos do paleoambiente. Predominam gramíneas com presença de algumas á...

RESUMO: Os sambaquis são sítios de pescadores-caçadores-coletores que contém conjuntos da fauna e flora existentes à época em que se formaram. O sambaqui sob rocha Casa de Pedra (São Francisco do Sul), em Santa Catarina, foi estudado a partir de análises de fitólitos para interpretar aspectos do paleoambiente. Predominam gramíneas com presença de a...

Phytolith analysis has become a useful tool for paleoenvironmental studies. Phytoliths are produced by plants and are composed of biogenic silica, giving them higher resistance to diagenetic and oxidation processes that commonly occur in tropical sediments. Here, we analyzed the preserved phytolith assemblages in a sedimentary core recovered from a...

Analyses of sediment cores recovered from the Negra Lake (NL) provide a new perspective on the environmental history of the central Pantanal wetlands for the last 19,000 yrs. Stratigraphy and multiple proxies (sponge spicules and phytoliths) suggest six depositional units. Lithostratigraphic units of deglacial age suggested varied paleoenvironments...

Estudos paleoambientais desde ~50.000 anos na costa do Brasil e, em particular, no litoral do Espírito Santo, são ainda insuficientes para servir de base a reconstituições da dinâmica da vegetação, de oscilações do nível relativo do mar e de flutuações climáticas e respectivas influências sobre a ação humana milenar. Para obter essas informações, u...

A falta de planejamento adequado para a composição e estruturação da arborização urbana, acarreta inúmeros conflitos com os pedestres, equipamentos públicos e privados, que por sua vez elevam os custos com a manutenção destas áreas. Neste contexto é importante a realização de estudos que façam o levantamento da arborização municipal com a finalidad...

The research characterizes and quantifies the phytoliths in Chloris elata Desv., Chloris gayana Kunth, and Tripogon spicatus (Ness) Ekman (Chloridoideae). Phytolith extraction from root, stalk, leaf and panicle/spike was carried out by acid dissolution (HNO3 and H2SO4); after counting and identification, saddle (87.1% without similarity to other mo...

The Pantanal is the world's largest tropical wetland and a biodiversity hotspot, yet its response to Quaternary environmental change is unclear. To address this problem, sediment cores from shallow lakes connected to the Upper Paraguay River (PR) were analyzed and radiocarbon dated to track changes in sedimentary environments. Stratal relations, de...

Phytoliths can be considered the most durable terrestrial fossil records, constituting an important proxy indicator for paleoenvironmental and archeological studies. This study shows the Butia paraguayensis (Barb. Rodr.) L. H. Bailey (Arecaceae) phytoliths forms, typical specie from cerrado vegetation (Brazilian savanna), considered endangered, as...