TY  - JOUR
A1  - Musolff, Andreas
A1  - Selle, Benny
A1  - Buttner, Olaf
A1  - Opitz, Michael
A1  - Tittel, Jörg
T1  - Unexpected release of phosphate and organic carbon to streams linked to declining nitrogen depositions
JF  - Global change biology
N2  - Reductions in emissions have successfully led to a regional decline in atmospheric nitrogen depositions over the past 20 years. By analyzing long-term data from 110 mountainous streams draining into German drinking water reservoirs, nitrate concentrations indeed declined in the majority of catchments. Furthermore, our meta-analysis indicates that the declining nitrate levels are linked to the release of dissolved iron to streams likely due to a reductive dissolution of iron(III) minerals in riparian wetland soils. This dissolution process mobilized adsorbed compounds, such as phosphate, dissolved organic carbon and arsenic, resulting in concentration increases in the streams and higher inputs to receiving drinking water reservoirs. Reductive mobilization was most significant in catchments with stream nitrate concentrations < 6 mg L-1. Here, nitrate, as a competing electron acceptor, was too low in concentration to inhibit microbial iron(III) reduction. Consequently, observed trends were strongest in forested catchments, where nitrate concentrations were unaffected by agricultural and urban sources and which were therefore sensitive to reductions of atmospheric nitrogen depositions. We conclude that there is strong evidence that the decline in nitrogen deposition toward pre-industrial conditions lowers the redox buffer in riparian soils, destabilizing formerly fixed problematic compounds, and results in serious implications for water quality.
KW  - atmospheric deposition
KW  - carbon cycle
KW  - nitrogen biogeochemistry
KW  - organic matter
KW  - riparian zone
KW  - streamwater chemistry
Y1  - 2017
U6  - https://doi.org/10.1111/gcb.13498
SN  - 1354-1013
SN  - 1365-2486
VL  - 23
SP  - 1891
EP  - 1901
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Wölfl, S.
A1  - Tittel, Jörg
A1  - Zippel, Barbara
A1  - Kringel, R.
T1  - Occurrence of an algal mass development in an acidic (pH 2.5), iron and aluminium-rich coal mining pond
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Bissinger, Vera
A1  - Jander, Jörn
A1  - Tittel, Jörg
T1  - A new medium free of organic carbon to cultivate organisms from extremely acidic mining lakes (pH 2.7)
N2  - An algal culture medium was developed which reflects the extreme chemical conditions of acidic mining lakes (pH 2.7, high concentrations of iron and sulfate) and remains stable without addition of organic carbon sources. It enables controlled experiments e.g. on the heterotrophic potential of pigmented flagellates in the laboratory. Various plankton organisms isolated from acidic lakes were successfully cultivated in this medium. The growth rates of an Chlamydomonas- isolate from acidic mining lakes were assessed by measuring cell densities under pure autotrophic and heterotrophic conditions (with glucose as organic C-source) and showed values of 0.74 and 0.40, respectively.
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Tittel, Jörg
A1  - Weithoff, Guntram
A1  - Bissinger, Vera
A1  - Gaedke, Ursula
T1  - Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Bissinger, Vera
A1  - Tittel, Jörg
T1  - Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 3) mining lakes in Germany
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Klapper, H.
A1  - Boehrer, Bertram
A1  - Packroff, G.
A1  - Schultze, M.
A1  - Tittel, Jörg
A1  - Wendt-Potthoff, Katrin
T1  - Bergbaufolgegewässer
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Stottmeister, Ulrich
A1  - Weißbrodt, Erika
A1  - Tittel, Jörg
T1  - Von der Altlast zum See : natürliche Selbstreinigung
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Koschorreck, Matthias
A1  - Frömmichen, René
A1  - Herzsprung, Peter
A1  - Tittel, Jörg
A1  - Wendt-Potthoff, Katrin
T1  - Function of straw for in situ remediation of acidic mining lakes
Y1  - 2002
SN  - 0049-6979
ER  - 
TY  - JOUR
A1  - Koschorreck, Matthias
A1  - Tittel, Jörg
T1  - Benthic photosynthesis in an acidic mining lake (pH 2.6).
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Tittel, Jörg
A1  - Bissinger, Vera
A1  - Zippel, Barbara
A1  - Gaedke, Ursula
A1  - Bell, Elanor M.
A1  - Lorke, Andreas
A1  - Kamjunke, Norbert
T1  - Mixotrophs combine resource use to outcompete specialists: Implications for aquatic food webs
N2  - The majority of species can be grouped into those relying solely on photosynthesis (phototrophy) or those relying solely on the assimilation of organic substances (heterotrophy) to meet their requirements for energy and carbon. However, a special life history trait exists in which organisms combine both phototrophy and heterotrophy. Such 'mixotrophy' is a widespread phenomenon in aquatic habitats and is observed in many protozoan and metazoan organisms. The strategy requires investment in both photosynthetic and heterotrophic cellular apparatus, but the benefits must outweigh these costs. In accordance with the mechanistic resource competition theory, laboratory experiments revealed that pigmented mixotrophs combined light and prey as substitutable resources. Thereby, they reduced prey abundance below the critical food concentration of competing specialist grazers [Rothhaupt, K. O. (1996) Ecology 77, 716-724]. Here, we demonstrate for the first time the important consequences of this strategy for an aquatic community. In the illuminated surface strata of a lake, mixotrophs reduced prey abundance so steeply that grazers from higher trophic levels, consuming both the mixotrophs and their prey, could not persist. Thus, the mixotrophs escaped from both competition and grazing, and remained dominant. Furthermore, the mixotrophs structured the prey abundance along the vertical light gradient creating low densities near the surface and a pronounced maximum of their algal prey at depth. Such deep algal accumulations are typical features of nutrient poor aquatic habitats, previously explained by resource availability. We hypothesize instead that the mixotrophic grazing strategy is responsible for deep algal accumulations in many aquatic environments.
Y1  - 2003
UR  - www.pnas.org/cgi/doi/10.1073/pnas.2130696100
ER  -