Taking Sweden and the whole Baltic Sea region as examples, the study shows also that the reported Swedish loads of nitrogen and phosphorous to the Baltic Sea are significantly smaller than expected from strong correlations between a country’s nutrient loads and its population, area and economic activity (GDP per capita) within the Baltic Sea drainage basin (BSDB), which are found for all other Baltic Sea countries. Erroneous calculation of the nutrient loads from the relatively large Swedish unmonitored near-coastal areas can explain this significant difference between the reported and the expected nutrient loads from Sweden to the Baltic Sea.
The near-coastal areas that are left without systematic environmental monitoring may be small, but they extend along most of the coastlines and often have a large population proportion. For the whole BSDB, for instance, these areas cover 13% of the total area and 24% of the total population of the BSDB, according to an earlier study(2) by the same research group. For Sweden, the corresponding fractions are even larger: 55% of the Swedish population in the 20% unmonitored near-coastal catchment area of Sweden(2). The new study(1) shows that, with such a large population proportion, the concentrations of, for instance, nitrogen, phosphorous and organic pollutants in the water flow that are generated within these small near-coastal catchment areas may be much larger that in the systematically monitored main rivers. The mass load to the sea from a catchment area is the product of the area’s water flow to the sea and the mass concentration in that water flow. The latter may be large in near-coastal catchment areas, both due to a large population and due to increasing seawater intrusion into the near-coastal groundwater, which changes chemical conditions and may re-mobilise pollutants that were previously adsorbed on the solid particles of the groundwater system.
The unmonitored near-coastal catchment areas are not just forgotten when, for instance, the Swedish nutrient loads to the Baltic Sea are estimated. The data gaps are bridged with the help of computer model calculations. However, because the model results cannot be checked against representative field data for the unmonitored areas, they may be significantly wrong. A series of earlier and parallel, detailed process studies from the SU research group have shown: 1) that near-coastal catchment areas have particularly complex water flow conditions, which are not only possibly, but even probably erroneously estimated where some necessary data is missing(3-4); and 2) that the subsurface water systems (soil, groundwater, sediments) of catchment areas contain large legacies and long-term memories of the cumulative anthropogenic inputs of nutrients and pollutants in the catchments over at least the last decades(5-7), which can now be continuously transported to the sea, without detection, along the long coastlines of unmonitored near-coastal catchment areas. The new study(1) synthesizes main implications of these earlier and parallel studies and suggests a concrete, improved methodology for interpreting available field data and estimating the mass loading to the sea from unmonitored near-coastal catchment areas.
7 Destouni G., The subsurface water system role for surface and coastal water pollution, Ecohydrology & Hydrobiology, 7(2), 157-164, 2007.
Maria Sandqvist | alfa
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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