Coordenacao de Ciencias da Terra e Ecologia

Belém, Brazil

Coordenacao de Ciencias da Terra e Ecologia

Belém, Brazil
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Vasconcelos H.L.,Federal University of Uberlandia | Vilhena J.M.S.,National Institute of Amazonian Research | Facure K.G.,Federal University of Uberlandia | Albernaz A.L.K.M.,Coordenacao de Ciencias da Terra e Ecologia
Journal of Biogeography | Year: 2010

Aim To determine the effect and relative importance of geographic and local environmental factors on species richness and turnover of ant assemblages in floodplain forests across the Amazon basin. Location Twenty-six mature forest sites scattered along the entire extension of the Amazon River in Brazil. The study area encompassed nearly 18° of longitude and 3.5° of latitude. Methods Systematic collections of ants were performed at each site during the low-water season (i.e. when forests are not inundated) using three complementary sampling methods. We used variance partitioning techniques to assess the relative effects of the spatial (latitude and longitude) and environmental (rainfall, length of the dry season and flood height) variables on ant species richness and composition. Results There was a twofold variation in the number of species per site, which was largely explained by inter-site variations in rainfall seasonality and flooding intensity. In general, there were more species at sites located in the western part of the basin, where the dry season is less severe, or near the river estuary, where precipitation is also high and flooding is less intense. Ant community composition was also affected by environmental heterogeneity. For instance, some species only occurred at those sites less affected by the river's seasonal flooding, whereas others were mostly associated with the drier or wetter regions of the basin. In addition, the turnover of species increased significantly as geographic distances increased. Nevertheless, the rate of change was small given that many species had a broad distribution across the study area. Main conclusions Ant distribution patterns along the floodplain forests of the Amazon appear to be controlled to a relatively large extent by the current gradient in flooding intensity and - most importantly - in precipitation. Altered rainfall regimes resulting from global warming and land-use change thus have the potential to influence these patterns. © 2009 Blackwell Publishing Ltd.


Gross M.,Universalmuseum Joanneum | Piller W.E.,University of Graz | Ramos M.I.,Coordenacao de Ciencias da Terra e Ecologia | Douglas da Silva Paz Jackson J.,Federal University of Mato Grosso
Journal of South American Earth Sciences | Year: 2011

In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ18O and δ13C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake (" Lake Pebas" ) or any influx of marine waters can be excluded for that region during the Late Miocene. © 2011 Elsevier Ltd.


Gross M.,Universalmuseum Joanneum | Ramos M.I.F.,Coordenacao de Ciencias da Terra e Ecologia | Piller W.E.,University of Graz
Journal of Systematic Palaeontology | Year: 2015

A huge wetland (the ‘Pebas system’) covered western Amazonia during the Miocene, hosting a highly diverse and endemic aquatic fauna. One of the most contentious issues concerns the existence, potential pathways and effects of marine incursions on this ecosystem. Palaeontological evidences (body fossils) are rare. The finding of a new, presumably marine ostracod species (Pellucistoma curupira sp. nov.) in the upper middle Miocene Solimões Formation initiated a taxonomic, ecological and biogeographical review of the genus Pellucistoma. We demonstrate that this marine (sublittoral, euhaline), subtropical–tropical taxon is biogeographically confined to the Americas. The biogeographical distribution of Pellucistoma largely depends on geographical, thermal and osmotic barriers (e.g. land bridges, deep and/or cold waters, sea currents, salinity). We assume an Oligocene/early Miocene, Caribbean origin for Pellucistoma and outline the dispersal of hitherto known species up to the Holocene. Pellucistoma curupira sp. nov. is dwarfed in comparison to all other species of this genus and extremely thin-shelled. This is probably related to poorly oxygenated waters and, in particular, to strongly reduced salinity. The associated ostracod fauna (dominated by the eurypotent Cyprideis and a few, also stunted ostracods of possibly marine ancestry) supports this claim. Geochemical analyses (δ18O, δ13C) on co-occurring ostracod valves (Cyprideis spp.) yielded very light values, indicative of a freshwater setting. These observations point to a successful adaptation of P. curupira sp. nov. to freshwater conditions and therefore do not signify the presence of marine water. Pellucistoma curupira sp. nov. shows closest affinities to Caribbean species. We hypothesize that Pellucistoma reached northern South America (Llanos Basin) during marine incursions in the early Miocene. While larger animals of marine origin (e.g. fishes, dolphins, manatees) migrated actively into the Pebas wetland via fluvial connections, small biota (e.g. P. curupira sp. nov.) were phoretically freighted and developed freshwater tolerance over long timescales. http://zoobank.org/urn:lsid:zoobank.org:pub:886C6476-393D-4323-8C0E-06BB8BD02FD9 © The Trustees of the Natural History Museum, London 2015. All rights reserved.


Gross M.,Universalmuseum Joanneum | Ramos M.I.,Coordenacao de Ciencias da Terra e Ecologia | Caporaletti M.,University of Graz | Piller W.E.,University of Graz
Journal of South American Earth Sciences | Year: 2013

Western Amazonia's landscape and biota were shaped by an enormous wetland during the Miocene epoch. Among the most discussed topics of this ecosystem range the question on the transitory influx of marine waters. Inter alia the occurrence of typically brackish water associated ostracods is repeatedly consulted to infer elevated salinities or even marine ingressions. The taxonomical investigation of ostracod faunas derived from the upper part of the Solimões Formation (Eirunepé; W-Brazil) documents a moderately diverse assemblage (19 species). A wealth of freshwater ostracods (mainly Cytheridella, Penthesilenula) was found co-occurring with taxa (chiefly Cyprideis) usually related to marginal marine settings today. The observed faunal compositions as well as constantly very light δ18O- and δ13C-values obtained by measuring both, the freshwater and brackish water ostracod group, refer to entirely freshwater conditions. These results corroborate with previous sedimentological and palaeontological observations, which proposed a fluvial depositional system for this part of western Amazonia during the Late Miocene. We demonstrate that some endemic, " brackish" water ostracods (i.e., Cyprideis) have been effectively adapted to freshwater conditions. Thus, their occurrence is no univocal evidence for the influence of brackish or marine waters in western Amazonia during the Miocene. © 2012 Elsevier Ltd.


Ramos M.I.F.,Coordenacao de Ciencias da Terra e Ecologia | Coimbra J.C.,Federal University of Rio Grande do Sul | Bergue C.T.,University of the Rio dos Sinos Valley | Whatley R.C.,Aberystwyth University
Ameghiniana | Year: 2012

The present study is a further contribution to the systematic knowledge of the ostracods from the southern Brazilian continental shelf. Twelve species of Trachyleberididae are recorded, including the following six new taxa: Cativella ornelasae sp. nov., C. sudbrasilienis sp. nov. sp., Henryhowella inflata sp. nov., Henryhowella verrucosa sp. nov., Ambocythere venusta sp. nov. and Basslerites costata sp. nov. The other six species have been recorded in previous studies, either in shallow or bathyal depths in both Brazilian waters and adjacent areas. Most species recorded herein are distributed in the neritic zone, except three, i.e., Trachyleberis aorata, Ambocythere venusta sp. nov. and C. sudbrasilienis sp. nov. The first two species are eurybathic, while C. sudbrasilienis sp. nov. is restricted to the inner shelf.


PubMed | Coordenacao de Ciencias da Terra e Ecologia, University of Graz, Universalmuseum Joanneum and Federal University of Mato Grosso
Type: Journal Article | Journal: Journal of South American earth sciences | Year: 2015

In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunep (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimes Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light


PubMed | Coordenacao de Ciencias da Terra e Ecologia, Universalmuseum Joanneum and University of Graz
Type: Journal Article | Journal: Journal of systematic palaeontology | Year: 2016

A huge wetland (the Pebas system) covered western Amazonia during the Miocene, hosting a highly diverse and endemic aquatic fauna. One of the most contentious issues concerns the existence, potential pathways and effects of marine incursions on this ecosystem. Palaeontological evidences (body fossils) are rare. The finding of a new, presumably marine ostracod species (


Moraes-Santos H.,Coordenacao de Ciencias da Terra e Ecologia | Villanueva J.B.,Federal University of Acre | Toledo P.M.,National Institute for Space Research
Zoological Journal of the Linnean Society | Year: 2011

New specimens of gavialoids collected from the Pirabas Formation, Brazil, provide additional information about the evolutionary evolution of Gavialoidea during the late Oligocene-early Miocene. We describe a specimen that has a more gracile symphyseal mandible than any other South American gavialoid. This fossil represents an unusually diverse radiation of gavialoids that were probably ecologically differentiated from each other by size and dietary specialization. © 2011 The Linnean Society of London.


Griffiths N.,Royal Holloway, University of London | Muller W.,Royal Holloway, University of London | Johnson K.G.,Natural History Museum in London | Aguilera O.A.,Coordenacao de Ciencias da Terra e Ecologia
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2013

Early Miocene corals (Siderastrea conferta and Montastraea limbata) from the Paraguaná Peninsula, Venezuela and a modern coral (S. radians) from Bermuda were examined in order to quantitatively assess the effect of skeletal preservation on element/Ca proxies used for palaeo-environmental reconstructions. The biostratigraphic age (Burdigalian) of the corals was confirmed via Sr isotope stratigraphy to 16.5 ± 0.4. Ma. Light and scanning electron microscopy revealed the presence of aragonite and calcite cements in both fossil and modern corals, but brucite cements were found only in the modern coral. Cement distribution is very heterogeneous, resulting in zones of excellent preservation juxtaposed with less well preserved regions in both modern and fossil coral. Oil-filled pore spaces were noted in the fossil specimens. Targeted LA-ICPMS depth profile analyses showed significant differences in Sr/Ca, Mg/Ca, B/Ca, Ba/Ca and U/Ca in aragonite and calcite cements compared to primary skeletal aragonite. Increased Sr/Ca and decreased Mg/Ca ratios were found in aragonite cements compared to skeletal aragonite, whereas in calcite cements these trends were reversed. B/Ca ratios were lower in both aragonite and calcite cements compared to primary aragonite. Estimates of the effect of 1% contamination by aragonite cements on coral Sr/Ca, Mg/Ca, B/Ca and U/Ca palaeo-sea-surface-temperature reconstructions for the fossil corals produced anomalies of - 1.2. °C, - 0.2. °C, + 0.3. °C and - 0.1. °C respectively. Similar percentage calcite cement contamination produced temperature anomalies of + 1.7. °C, + 2.7. °C, + 0.3. °C and - 0.1. °C. Because of both highly elevated and depleted Ba/Ca signatures in aragonite and calcite cements respectively, care has to be exercised when reconstructing past flood or upwelling events from fossil corals. When using targeted spatially-resolved analysis, well-preserved early Miocene corals may overall yield reliable 'deep-time' palaeo-proxy information in much the same way as commonly utilised Holo/Pleistocene corals. © 2012.


Barros D.F.,Coordenacao de Ciencias da Terra e Ecologia | Albernaz A.L.M.,Coordenacao de Ciencias da Terra e Ecologia
Brazilian Journal of Biology | Year: 2014

Wetlands cover approximately 6% of the Earth´s surface. They are frequently found at the interface between terrestrial and aquatic ecosystems and are strongly dependent on the water cycle. For this reason, wetlands are extremely vulnerable to the effects of climate change. Mangroves and floodplain ecosystems are some of the most important environments for the Amazonian population, as a source of proteins and income, and are thus the types of wetlands chosen for this review. Some of the main consequences that can be predicted from climate change for wetlands are modifications in hydrological regimes, which can cause intense droughts or inundations. A possible reduction in rainfall can cause a decrease of the areas of mangroves and floodplains, with a consequent decline in their species numbers. Conversely, an increase in rainfall would probably cause the substitution of plant species, which would not be able to survive under new conditions for a long period. An elevation in water temperature on the floodplains would cause an increase in frequency and duration of hypoxic or anoxic episodes, which might further lead to a reduction in growth rates or the reproductive success of many species. In mangroves, an increase in water temperature would influence the sea level, causing losses of these environments through coastal erosion processes. Therefore, climate change will likely cause the loss of, or reduction in, Amazonian wetlands and will challenge the adaptability of species, composition and distribution, which will probably have consequences for the human population that depend on them. © 2014, Instituto Internacional de Ecologia. All rights reserved.

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