Future Trends in Nutrient Export to the Coastal Waters of South America: Implications for Occurrence of Eutrophication

We analyze future trends in nutrient export to the coastal waters of South America, with a special focus on the causes of nutrient export and their potential effects. Nutrient Export from Watersheds (NEWS) model results for South America are presented, including trends in human activities and the associated river export of nutrients for the period 1970–2050. For 25 areas in coastal waters of South America where eutrophication or hypoxia has been observed, we investigate how these relate to NEWS model output. For selected watersheds we discuss the causes of increased nutrient loadings of rivers and future trends as projected by the NEWS model

Nutrients Export by Rivers to the Coastal Waters of Africa: Past and Future trends

We analyze past and future trends in nitrogen (N), phosphorus (P), and carbon (C) export by rivers to the coastal waters of Africa as calculated by the Global Nutrient Export to WaterShed (NEWS) models for the period 1970–2050. Between 1970 and 2000 the total nutrient export by African rivers increased by 10–80%. For future years (2000–2050) we calculate an increase in the total loads of dissolved forms of N and P, but decreasing trends for dissolved organic C and particulate forms of N and P. There are large regions that deviate from these pan-African trends. We explore the regional patterns and the underlying processes, in particular for the Nile, Zaire, Niger, and Zambezi. In the future, anthropogenic sources may, in large parts of Africa, become larger contributors to riverine nutrient loads than natural source

Een toekomst vol verrassingen

In de milieukunde bestuderen we milieuproblemen graag van begin tot eind: de onderliggende oorzaken, daaruit volgende milieudruk en veranderingen in het milieusysteem, de effecten op ecosystemen en maatschappij, en de mogelijke oplossingen. Natuurlijke ecosystemen reageren niet altijd zoals we verwachten. Onze conservatieve modellen zijn niet in staat om de reacties van gevoelige soorten op milieudruk in kaart te brengen. Projecten als de natuurkalender illustreren de onverwachte effecten van klimaatverandering. We voorspellen geen toekomst, maar verkennen verschillende mogelijke ontwikkelingen, op zoek naar oplossingen voor problemen die voor ons liggen op de natuur in onze achtertui

Millennium Ecosystem Assessment Scenario drivers (1970-2050): Climate and hydrological alterations

This study was carried out to support and enhance a series of global studies assessing contemporary and future changes in nutrient export from watersheds (Global Nutrient Export from Watersheds (NEWS)). Because hydrography is one of the most important drivers in nutrient transport, it was essential to establish how climatic changes and direct human activities (primarily irrigation and reservoir operations) affect the hydrological cycle. Contemporary and future hydrography was established by applying a modified version of a global water balance and transport model (WBMplus) driven by present and future climate forcing, as described in the Millennium Ecosystem Assessment scenarios (1970-2050). WBMplus represents a major upgrade to previous WBM implementations by incorporating irrigational water uptake and reservoir operations in a single modeling framework. Contemporary simulations were carried out by using both observed climate forcings from the Climate Research Unit of East Anglia (CRU) data sets and from Global Circulation Model (GCM) simulations that are comparable to the future simulations from the same GCM forcings. Future trends in three key human activities (land use, irrigation, and reservoirs operation for hydropower) were taken from the Integrated Model to Assess the Global Environment (IMAGE). The reservoir operation required establishing a realistic distribution of future reservoirs since the IMAGE model provided only the hydropower potentials for the different future scenarios

Latitudinal and Altitudinal Distribution of Carbon Dioxide, Halocarbons, Nitrous Oxide, Methane, Carbon Monoxide and Hydroxyl in the Atmosphere

Due to human activities, atmospheric concentrations of several gases have been increasing during the past century. Some of these gases are so-called greenhouse gases and play an important role in the earth's climate. Increasing concentrations of greenhouse gases may ultimately result in global climate change. In order to investigate regional effects of the enhanced greenhouse effect, 1- to 3-dimensional computer simulation models are being developed. For the calculation of radiative transfer through the atmosphere, these models require basic information with regard to the latitudinal and/or altitudinal distribution of greenhouse gases in the atmosphere. The purpose of this study is to give an overview of the spatial variations of atmospheric greenhouse gas concentrations. Data from several measurement programs are used to obtain first order estimates of latitudinal and height profiles of carbon dioxide (CO2), several halocarbons (CFC-11, CFC-12, CFC-113, HCFC-22, CH3CCl3 and CCl4), nitrous oxide (N2O) and methane (CH4). Also carbon monoxide (CO) and hydroxyl (OH) are considered because these gases may influence CH4 concentrations. An attempt is made to explain the observed gradients qualitatively. If possible, some conclusions are drawn with regard to the preindustrial and future distributions of the gases. The results show that the present concentrations of all greenhouse gases at the earth's surface are higher in the northern than in the southern hemisphere. The main reason for this may be the fact that most emissions of these gases originate from the northern hemisphere. The profiles with height differ for the gases. In case the main sink is located in the stratosphere (for instance for CFCs and N2O), a steep gradient with height is observed above the tropopause

An analysis of the environmental pressure exerted by the eucalyptus-based Kraft pulp industry in Thailand

The study reported here focuses on the environmental pressure exerted by large-scale eucalyptus-based kraft pulp industry in Thailand. The objective of this study was to identify the most important sources of greenhouse gases, acidifying and eutrophying compounds and tropospheric ozone precursors, human toxicity compounds and solid waste associated with the kraft pulp industry. To this end, we performed an environmental systems analysis of the kraft pulp industry system in which we distinguished between two subsystems: the eucalyptus forestry subsystem and the kraft pulp production subsystem. The results indicate that the environmental pressure is caused by the kraft pulp production subsystem rather than by the eucalyptus forestry one. The chemical recovery unit was found to be the most important source of carbon dioxide (CO2) and sulfur dioxide (SO2) and responsible for more than one-half of the emissions of greenhouse gases and acidifying compounds from eucalyptus-based kraft pulp production in Thailand. Biomass combustion in the energy gene ration unit is an important source of nitrogen oxide (NOx) and carbon monoxide (CO) which in turn are responsible for over 50% of the emissions of tropospheric ozone precursors. About 73% of the eutrophication is caused by biological aerobic wastewater treatment emitting phosphorus (P). With respect to the eucalyptus forestry, only fertilizer use in eucalyptus plantations is a relevant source of pollution through the emission of nitrous oxide (N2O) and phosphate (PO4 3-)

Understanding nutrient loading and sources in the Bay of Bengal Large Marine Ecosystem

Inputs of nitrogen, phosphorous and dissolved silica from watersheds draining into the Bay of Bengal Large Marine Ecosystem are calculated for the present day and predictions made for 2030 and 2050 are presented. The major sources are identified and the Indicator of Coastal Eutrophication (ICEP) is calculated

From Tags to Topic Maps: Using Marked-up Hebrew Text to Discover Linguistic Patterns

The paper discusses a series of related techniques that prepare and transform raw linguistic data for advanced processing in order to unveil hidden grammatical patterns. It identifies XML as a suitable mark-up language to build an exploitable data bank of multi-dimensional data in the Hebrew text of the Old Testament. This concept is illustrated by tagging a transcription of Gen. 1:1-2:3 and manipulating this data bank. Transferring the data into a three-dimensional array allows advanced processing of the data in order to either confirm existing knowledge or to mine for new, yet undiscovered, linguistic features. Visualisation is discussed as a technique that enhances interaction between the human researcher and the computerised technologies supporting this process of knowledge creation. The empirical study is a small experiment that illustrates the viability and usefulness of the proposed expert devices as well as the benefits of applying information system techniques to linguistic databases

Assessing seasonal nitrogen export to large tropical lakes

Rivers are exporting increasing amounts of nitrogen (N) to lakes, which is leading to eutrophication. However, the seasonality apparent in nutrient loading, especially in tropical areas, is thus far only partially understood. This study aims to better understand the seasonality and the sources of dissolved inorganic nitrogen (DIN) inputs from sub-basins to tropical lakes. We integrated existing approaches into a seasonal model that accounts for seasonality in human activities, meteorology and hydrology, and we applied the model to the sub-basins of a representative tropical lake: Lake Tana, Ethiopia. The model quantifies the river export of DIN by season, source and sub-basin and also accounts for open defecation to land as a diffuse source of N in rivers. Seasonality parameters were calibrated, and model outputs were validated against measured nitrogen loads in the main river outlets. The calibrated model showed good agreement with the measured nitrogen loads at the outflow of the main rivers. The model distinguishes four seasons: rainy (July–September), post-rainy (October–December), dry (January–March) and pre-rainy (April–June). The river export of DIN to Lake Tana was about 9 kton in 2017 and showed spatial and temporal variability: It was highest in the rainy and lowest in the dry seasons. Diffuse sources from agriculture were important contributors of DIN to rivers in 2017, and animal manure was the dominant source in all seasons. Our seasonal sub-basins and rivers model provides opportunities to identify the main nutrient sources to the lake and to formulate effective water quality management options. An example is nutrient application level that correspond to the crop needs in the sub-basins. Furthermore, our model can be used to analyse future trends and serves as an example for other large tropical lakes experiencing eutrophication.</p