title: Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs.
abstract: Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.
authors.affiliation: Department of Environmental Science and Analytical Chemistry, Stockholm University, 106 91, Stockholm, Sweden, agnes.karlson@aces.su.se.
authors.forename: Agnes M L
authors.initials: AM
authors.lastname: Karlson
authors.forename: Jon
authors.initials: J
authors.lastname: Duberg
authors.forename: Nisha H
authors.initials: NH
authors.lastname: Motwani
authors.forename: Hedvig
authors.initials: H
authors.lastname: Hogfors
authors.forename: Isabell
authors.initials: I
authors.lastname: Klawonn
authors.forename: Helle
authors.initials: H
authors.lastname: Ploug
authors.forename: Jennie
authors.initials: J
authors.lastname: Barthel Svedén
authors.forename: Andrius
authors.initials: A
authors.lastname: Garbaras
authors.forename: Brita
authors.initials: B
authors.lastname: Sundelin
authors.forename: Susanna
authors.initials: S
authors.lastname: Hajdu
authors.forename: Ulf
authors.initials: U
authors.lastname: Larsson
authors.forename: Ragnar
authors.initials: R
authors.lastname: Elmgren
authors.forename: Elena
authors.initials: E
authors.lastname: Gorokhova
mesh_terms: D000818:Animals; D000458:Cyanobacteria / Q000378:metabolism*; D005399:Fishes; D009586:Nitrogen Fixation / Q000502:physiology*