One of the most serious problems caused by eutrophication of shallow lakes is the disappearance of submerged macrophytes and the switch to a turbid, phytoplankton-dominated state. The reduction of external nutrient loads often does not result in a change back to the macrophyte-dominated state because stabilising mechanisms that cause resilience may delay a response. Additional internal lake restoration measures may therefore be needed to decrease the concentration of total phosphorus and increase water clarity. The re-establishment of submerged macrophytes required for a long-term stability of clear water conditions, however, may still fail, or mass developments of tallgrowing species may cause nuisance for recreational use. Both cases are often not taken into account when restoration measures are planned in Germany, and existing schemes to reduce eutrophication consider the topic inadequately.Here we develop a step-by-step guideline to assess the chances of submerged macrophyte re-establishment in shallow lakes. We reviewed and rated the existing literature and case studies with special regard on (1) the impact of different internal lake restoration methods on the development of submerged macrophytes, (2) methods for the assessment of natural re-establishment, (3) requirements and methods for artificial support of submerged macrophyte development and (4) management options of macrophyte species diversity and abundance in Germany. This guideline is intended to help lake managers aiming to restore shallow lakes in Germany to critically asses and predict the potential development of submerged vegetation, taking into account the complex factors and interrelations that determine their occurrence, abundance and diversity.

In running waters, apart from structural degradation, nutrient input becomes increasingly important. To investigate the indicator values of as many species of submerged macrophytes as possible numerous samples of the sediment within macrophyte stands and the overlying water were taken in running waters throughout Bavaria, Germany. To develop the Trophic Index of Macrophytes (TIM), the concentrations of soluble reactive phosphorus of both the water body and the sediment pore water were used. Based on a weighted sum of the SRP-concentrations of the water body and the sediment pore water, indicator values were determined for a total of 49 species of submerged macrophytes. A detailed method is described on how and depending on which preconditions the trophic state of running waters can be determined by the TIM. An example of the TIM in the stream Rotbach is given. It shows that the TIM is a useful means to detect differences in the phosphorus loading of running waters.

Aquatic macrophytes can serve as useful indicators of water pollution along the littoral of lakes. In Bavaria, the submerged vegetation of about 100 lakes has been investigated by SCUBA diving over the past decade to evaluate the state of nutrient pollution. All lakes are marl lakes located in the northern calcareous alps and the prealpine region. The lakes differ in size, morphology, water residence time, nutrient loading, trophic status, recreational activities, and other characteristics. In all cases the entire shoreline of the lakes has been investigated. Among the investigated lakes are the three biggest Bavarian lakes, i.e. Lake Chiemsee, Lake Starnberg and Lake Ammersee. Mapping of the submerged vegetation occurred in four different depth zones, and variable shoreline sections. The length of each section was determined by the uniformity of the vegetation; as it changed, a new section was designated. Within each section and zone species were recorded and abundance of all observed macrophytes was estimated semi-quantitatively on a five-point scale. Nine different groups of macrophytes were recognised, including, in total, 45 different species of macrophytes. On the basis of this catalogue of indicator species, in combination with the abundance of the species, a 'macrophyte index' was devised, which ranges from 1 (unpolluted) to 5 (heavily polluted). Six groups of values of the macrophyte index, each represented by a different colour or grey-scale (in this publication), are presented to allow a clear illustration of the results. Important information for the successful restoration of lakes in Upper Bavaria has been obtained from the distribution patterns of the submerged vegetation. Many unknown waste water inflows or diffuse sources could be detected due to abrupt changes in the macrophyte index. Furthermore, the success of waste water removal by 'ring canalisation', resulting in a re-oligotrophication of many Bavarian lakes can be followed by changes in the macrophyte index.

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Zn-MnO 2 alkaline batteries were investigated in-situ at different stages of electric discharge by synchrotron tomography with monochromatic X-rays and by neutron tomography. The spatial distribution and the changes in the morphology of different components of a battery caused by the reduction of MnO 2 , the dissolution of Zn and the nucleation and growth of ZnO are investigated with high spatial resolution around several µm with X-rays. Neutron tomography is used to monitor the changes in the spatial distribution of hydrogen in the MnO 2 matrix and provides complementary information about the process.