Criar Ciência

Antes de desenvolver o tema ―Criar ciência‖, propriamente dito, sinto a necessidade de definir alguns termos e de enquadrar alguns conceitos. Em primeiro lugar, este capítulo dedica-se às Ciências ditas Exatas e Naturais, sejam elas de caráter fundamental ou aplicado, podendo provavelmente grande parte do que aqui está escrito aplicar-se igualmente à Tecnologia. No entanto, será que os processos e conceitos ligados à criação da Ciência nestas áreas do conhecimento diferem dos que regem as Ciências Humanas e Sociais? Provavelmente não, mas cabe ao leitor responder a esta pergunta através dos textos aqui apresentados. Em segundo lugar, as próprias Ciências ditas Exatas e Naturais abrangem mundos tão diversos e distintos, tanto no que diz respeito às escalas abrangidas (espaciais ou temporais), como ao seu próprio estado de desenvolvimento, pelo que me é obviamente impossível abordar estas ciências no seu conjunto. Com estas palavras exemplifico perfeitamente, o dilema da maior parte dos cientistas: Como falar de um tema sabendo perfeitamente que o que se irá dizer, só se verifica para alguns casos específicos ou até mesmo para uma grande maioria, mas nunca para tudo e todos

Regional sea level change study based on estuarine sediment color and biogeochemistry - preliminary results

Coastal zones play a significant role in the regional development and have been an important area for human occupation through time. The study of estuarine sediments applied to sea level changes had always been of extreme importance, as it reflects the coastal line evolution, either by local, regional or global changes

An attempt to use color as a tool for high resolution correlations between estuarine sedimentary cores from Algarve (Portugal)

Nowadays, paleoenvironmental and climatological researches focus on studying shortterm climatic changes and one of the more sensitive environments for recording those short-term climatic variations are the high sedimentation rate of coastal regions. Accordingly, 4 estuaries from the Algarve region, south of Portugal, have been cored in order to study sedimentary and climatic variations during recent times (c.a. 5000 yrs). For this purpose, we applied sampling and analytical techniques from deep-sea studies, allowing the acquirement of almost continuous data profiles, as the color data obtained with the spectrophotometer Colortron

Correlation of estuarine sedimentary cores based on color analysis: an example from the Algarve region (Portugal)

Coastal zones play a significant role in the regional development and have been an important area for human occupation through time. The study of estuarine sediments applied to sea level changes had always been of extreme importance, as it reflects the coastal line evolution, either by local, regional or global changes

Is it possible to use "twin cores" as a unique sedimentary record? An experimental design based on sediment color

Sedimentary cores are widely used for studying Quaternary records. However, the amount of sediment that is available is proportional to the diameter of the core, which is rarely bigger than 15 cm. One way to obtain more sediment is to use two cores retrieved from almost the same location and use them as if they represent a unique sedimentary record. In the present work, an experimental design has been applied to verify if “twin cores” from an estuary can be considered as representing the same sedimentary record with twice the amount of sediment to study. Because sediment can be characterized based on its color, the variables used as replicates in the experimental design are the three Lab CIE colors acquired with a X-Rite Colortron spectrophotometer. Sediment cores were retrieved from the upper saltmarsh of Gilão River’s estuary, southern Portugal. Twin cores, with in between distances of 50 cm, 100 cm and 200 cm, from two different sites were analysed. Results from a nested ANOVA show that even for the closest twin cores (50 cm apart) there is at least one color variable that shows significant variations between the profiles of both cores. These results clearly show that “twin cores” cannot be used as a unique sedimentary record without any previous testing, at least in such transitional regions

Using Radium isotopes to evaluate the mixing timeline and relative age of waters in a leaky coastal lagoon

The Ria Formosa wetland system is classified as a leaky coastal lagoon and covers approximately 100 km2 of the South of Portugal, with roughly 50% being intertidal. Its hinterland is set in an arid region and on a coastal plain subject to intensive agriculture since the 50’s. In spite of high exchange coefficients with the coastal ocean (50 and 75% at neap and spring tides, respectively) and the annual total potential freshwater discharge from the hinterland a fraction of the daily tidal prism, worrying signs of eutrophication have been detected during the past couple of decades. These include fish- and clam-kill episodes, increased occurrence of nuisance algal blooms and substitution of native sea grass communities by macroalgae. Notwithstanding its critical importance for the evaluation of pollutant exposure period, the literature includes a wide range of estimates for the ‘residence time’ of waters within the lagoon (16 hours to 11 days, with an the apparent consensus falling within the 1-2 day interval) and this point is a clear obstacle for a correct environmental risk assessment, including management of the system. This lack of clarity is due in our view to two main factors: i) the lack of proper physical definition of the term ‘residence time’, with its consequent misuse and misapplication in context, a misconception that is unfortunately too common within the environmental community, and different concepts in the application of transport time scales ii) the geomorphological and hydraulic complexity of the system.. As part of ongoing research evaluating the role of Submarine Groundwater Discharge (SGD) as a loading vector for nutrients (especially Nitrate) into the lagoon, we use the radium quartet in combination with remote sensing and isotope mixing models to develop and discuss a mixing timeline for the system, We conclude that the average, whole-system residence time of waters within the lagoon is at least 4 days

Organic carbon accumulation in coastal zones since the last glacial maximum? A clue for varying atmospheric CO2 levels?

It is a generally accepted concept that the carbon storage within the principal earth surface reservoirs varies in a multitude of time scales. The shallow water continental margins belong to the most fertile areas in terms of organic carbon (OC) production and are also very effective carbon traps

Shore platforms as a proxy for sea level changes

Shore platforms show several morphological features that can be use as proxies for sea level changes. However, they are frequently difficult to date and form in tidal ranges that may overcome the relative mean sea level (rmsl) changes

Detection of speleothem growth bands with an open source geophysical software

Speleothem growth bands are commonly referred as one of the parameters that are used for paleoclimate reconstructions. Accordingly, this work presents a new tool for detecting these bands based on the gray-scale image of the speleothem using the Mirone open source geophysical software

Paleomagnetism in speleothems: influence of calcite growth dip on the natural remanent magnetization

Recent studies recognized speleothems as excellent recorders of the Earth’s magnetic field. However, some questions remain about the origin of the natural remanent magnetization and about the influence of the speleothem shape on the recorded magnetic directions.info:eu-repo/semantics/publishedVersio