title: Hypoxia-related processes in the Baltic Sea.
abstract: Hypoxia, a growing worldwide problem, has been intermittently present in the modern Baltic Sea since its formation ca. 8000 cal. yr BP. However, both the spatial extent and intensity of hypoxia have increased with anthropogenic eutrophication due to nutrient inputs. Physical processes, which control stratification and the renewal of oxygen in bottom waters, are important constraints on the formation and maintenance of hypoxia. Climate controlled inflows of saline water from the North Sea through the Danish Straits is a critical controlling factor governing the spatial extent and duration of hypoxia. Hypoxia regulates the biogeochemical cycles of both phosphorus (P) and nitrogen (N) in the water column and sediments. Significant amounts of P are currently released from sediments, an order of magnitude larger than anthropogenic inputs. The Baltic Sea is unique for coastal marine ecosystems experiencing N losses in hypoxic waters below the halocline. Although benthic communities in the Baltic Sea are naturally constrained by salinity gradients, hypoxia has resulted in habitat loss over vast areas and the elimination of benthic fauna, and has severely disrupted benthic food webs. Nutrient load reductions are needed to reduce the extent, severity, and effects of hypoxia.
authors: GeoBiosphere Science Centre, Lund University, SE-223 62 Lund, Sweden. daniel.conley@geol.lu.se
authors: Daniel J
authors: DJ
authors: Conley
authors: Svante
authors: S
authors: Björck
authors: Erik
authors: E
authors: Bonsdorff
authors: Jacob
authors: J
authors: Carstensen
authors: Georgia
authors: G
authors: Destouni
authors: Bo G
authors: BG
authors: Gustafsson
authors: Susanna
authors: S
authors: Hietanen
authors: Marloes
authors: M
authors: Kortekaas
authors: Harri
authors: H
authors: Kuosa
authors: H E Markus
authors: HE
authors: Meier
authors: Baerbel
authors: B
authors: Müller-Karulis
authors: Kjell
authors: K
authors: Nordberg
authors: Alf
authors: A
authors: Norkko
authors: Gertrud
authors: G
authors: Nürnberg
authors: Heikki
authors: H
authors: Pitkänen
authors: Nancy N
authors: NN
authors: Rabalais
authors: Rutger
authors: R
authors: Rosenberg
authors: Oleg P
authors: OP
authors: Savchuk
authors: Caroline P
authors: CP
authors: Slomp
authors: Maren
authors: M
authors: Voss
authors: Fredrik
authors: F
authors: Wulff
authors: Lovisa
authors: L
authors: Zillén
mesh_terms: D000693:Anaerobiosis; D001454:Baltic States; D002980:Climate; D009792:Oceans and Seas; D010100:Oxygen / Q000032:analysis* / Q000378:metabolism*; D012623:Seawater / Q000737:chemistry*
chemical_list: D010100:Oxygen