Nutrient limitation of bacterioplankton and phytoplankton in humic lakes in northern Sweden

• Published in: Freshwater Biology
• Main Authors: Jansson, Mats, Bergström, Ann‐Kristin, Drakare, Stina, Blomqvist, Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Northern Sweden
• Online Access: http://dx.doi.org/10.1046/j.1365-2427.2001.00703.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1365-2427.2001.00703.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2427.2001.00703.x

1. Two small humic lakes in northern Sweden with concentrations of dissolved organic carbon (DOC) between 15 and 20 mg L –1 were fertilized with inorganic phosphorus (P) and inorganic nitrogen (N), respectively. A third lake was unfertilized and served as a control. In addition to this lake fertilization experiment, data from different regional surveys were used to assess the role of different limiting factors. 2. The P fertilization had no effects on bacterioplankton or phytoplankton, while phytoplankton were significantly stimulated by N fertilization. Inorganic nutrient limitation of bacterioplankton was a function of DOC concentration in water of the investigated region and nutrient‐limited bacteria were found only in lakes with DOC concentrations less than around 15 mg L –1 3. The fertilization experiments demonstrated that the DOC‐rich experimental lakes contained a bioavailable pool of P that was not utilized to its full potential under natural conditions. The overall mobilization of energy (bacterioplankton plus phytoplankton) in the experimental lakes was restricted by lack of inorganic N.