caa a22 4500 467885486 CHVBK 20180406152733.0 cr unu---uuuuu 170328e20061101xx s 000 0 eng 10.1007/s10021-006-0167-1 doi (NATIONALLICENCE)springer-10.1007/s10021-006-0167-1 Iron Constraints on Planktonic Primary Production in Oligotrophic Lakes [Elektronische Daten] [Tobias Vrede, Lars J. Tranvik] Phototrophic primary production is a fundamental ecosystem process, and it is ultimately constrained by access to limiting nutrients. Whereas most research on nutrient limitation of lacustrine phytoplankton has focused on phosphorus (P) and nitrogen (N) limitation, there is growing evidence that iron (Fe) limitation may be more common than previously acknowledged. Here we show that P was the nutrient that stimulated phytoplankton primary production most strongly in seven out of nine bioassay experiments with natural lake water from oligotrophic clearwater lakes. However, Fe put constraints on phytoplankton production in eight lakes. In one of these lakes, Fe was the nutrient that stimulated primary production most, and concurrent P and Fe limitation was observed in seven lakes. The effect of Fe addition increased with decreasing lake water concentrations of total phosphorus and dissolved organic matter. Possible mechanisms are low import rates and low bioavailability of Fe in the absence of organic chelators. The experimental results were used to predict the relative strength of Fe, N, and P limitation in 659 oligotrophic clearwater lakes (with total phosphorus ≤ 0.2 μM P and total organic carbon < 6 mg C l−1) from a national lake survey. Fe was predicted to have a positive effect in 88% of these lakes, and to be the nutrient with the strongest effect in 30% of the lakes. In conclusion, Fe, along with P and N, is an important factor constraining primary production in oligotrophic clearwater lakes, which is a common lake-type throughout the northern biomes. Springer Science+Business Media, Inc., 2006 phytoplankton nationallicence primary production nationallicence nutrient limitation nationallicence micronutrients nationallicence oligotrophic clearwater lakes nationallicence Vrede Tobias Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 20, SE-752 36, Uppsala, Sweden aut Tranvik Lars J. Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 20, SE-752 36, Uppsala, Sweden aut Ecosystems Springer-Verlag; www.springer-ny.com 9/7(2006-11-01), 1094-1105 1432-9840 9:7<1094 2006 9 10021 https://doi.org/10.1007/s10021-006-0167-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-006-0167-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Vrede Tobias Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 20, SE-752 36, Uppsala, Sweden aut NATIONALLICENCE 700 1- Tranvik Lars J. Limnology/Department of Ecology and Evolution, Evolutionary Biology Centre, Uppsala University, Norbyvägen 20, SE-752 36, Uppsala, Sweden aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/7(2006-11-01), 1094-1105 1432-9840 9:7<1094 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer