Living Coast BSPC Group 15mar21

Regaining good ecological status incoastal areas – is that possible?Linda Kumblad & Emil RydinBaltic Sea Center, Stockholm UniversityLiving Coast – a full-scale remediation project(2011-2023)Achieve good status in coastal areas that:● are severely affected by eutrophication● have large extension of anoxic bottoms● have limited water exchangeBjörnöfjärden in Stockholm archipelago:● measures in catchment and bay● frequent monitoring (reference bay)● communication to stimulate actionIdentification of nutrient loadsto prioritize actions● Map land use and activities in the catchment● Measurements and calculations of nutrient transport● Anthropogenic and natural nutrient loads● Action potential and selection of measures● Both N and P important to reduce,... in this projectphosphorous (P) is often in focus.Measures to reduce nutrient inputConference center45 k P/yrAgriculture Small sewage systems38 kg P/yr 83 kg P/yrHorse keeping17 kg P/yrCatchment ca 15 km2Sediment600 kg P/yr Bay ca 1.5 km2Maximum depth 25 mSalinity ca 5 PSUSumming up the actions...., ca 70% P-reductionLoad prior actions: 840 kg P/år Load after actions: 240 kg P/årExternal: 240 kg P/yr (29%) External: 140 kg P/yr (58%)Internal: 600 kg P/yr (71%) Internal: 100 kg P/yr (42%)Background 7%Background 24%Agriculture 5%Agriculture 7%Horse keeping 2%Horse keeping 4%Private sewers 10%Private sewers 17%Conference center 5%Conference center 6%Internal load 42%Internal load 71%Phosphorus concentrationscut in half...● Less phytoplankton● Improved secchi depth● Benthic algae found deeper● Bottom water better oxygenated● Fish and benthos found deeper● Species composition of fish changingSummary & Conclusions● Improvements of enclosed coastal bays is possible● Reduce nutrient supply from land and sediment● Identify sources and prioritize actions● Holistic view and knowledge of the ecosystem● Time, patience and resourcesLEVA: Local engagement for water● SWAM support 20 pilot projects to strengthen the localremediation work for 2-3 years, 3.7 MEUR, 2018-2021● Create a new long-term approach● Implement more measures against eutrophicationStart-up meeting for Sweden ́s“remediation coordinators””Living bays” 2020-2027● Restoration of shallow wave‐protected bays● Case studies on effects on stressors● Identify concrete and cost-effective measures● Solid advice and recommendations for:– Local authorities– House owners– Communities– Boat clubs, etc.Thank you!linda.kumblad@su.seemil.rydin@su.sewww.balticsea2020.orgwww.levandekust.sewww.BalticSea2020.orgRydin et al. (2017) Environ. Sci. Technol.Rydin & Kumblad (2019) Est., Coast. Shelf Sci.Al-treatment reduced the P-release with 80%Nutrients cause algal bloom Aluminium (Al) bind phosphorus (P)Decomposition lead to anoxia Eutrophication ceaseAnoxia release phosphorus (P) The P cycle has been stopped