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The results show that these measures in combination can reduce the phosphorus
loads below the loads of the year 1960. However, in the early 1960s, the lagoon
was already in a highly eutrophic state. It is very likely that for an efficient pro-
tection of the Baltic Sea and a significant improvement of coastal water quality,
additional measures in the coastal waters themselves have to be applied. Possible
additional measures are mussel farms, managed mussel beds and enlarged natural
mussel beds, algal farms, increased reed belts (supported by pile rows) and extended
submersed macrophyte areas and/or dredging of sediment and dumping on land.
With the mussel or algal harvest, the nutrients would be removed back to the land
and would end up as fertilizer in agriculture. The nutrient cycle would be closed.
The results indicate that a phosphorus load reduction has only limited effect on
the eutrophic state of the lagoon. The lagoon is much more sensitive to nitrogen
load reductions. We strongly support Conley et al. ( 2009 ) , who consider both nitro-
gen and phosphorus as controlling elements for coastal and marine eutrophication
and ask for measures which reduce the loads of both elements. Integrated manage-
ment should always take all nutrients into account and should not merely focus on
the needs of the open Baltic Sea. Our results show that coastal systems have their
own dynamics, are important sinks and transformators and also act as temporary
sources for nutrients. A detailed understanding of the behaviour of coastal systems
is imperative for management.
Acknowedgements This chapter is dedicated to Horst Behrendt, who died, much too early,
in December 2008. The work has been supported by the projects IKZM-Oder III (Federal
Ministry for Education and Research; 03F0403A & 03F0465A) and BONUS+ project AMBER
(Assessment and Modelling Baltic Ecosystem Response). Data have been kindly supplied by
the State Agency of Environment, Protection of Nature and Geology Mecklenburg-Vorpommern
(LUNG). Supercomputing power was provided by HLRN (Norddeutscher Verbund für Hoch- und
Höchstleistungsrechnen).
References
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Weißensee Verlag, Berlin
Behrendt H, Opitz D, Kolanek A, Korol R, Stronska M (2008) Changes of the nutrient loads of
the Odra River during the last century - their causes and consequences. Journal of Water Land
Development 12:127-144
Boesch D, Hecky R, O'Melia C, Schindler D, Seitzinger S (2006) Eutrophication of Swedish
seas. Swedish Environmental Protection Agency, Naturvårdsverket, Stockholm, Sweden, ISBN
91-620-5509-7
Conley DJ, Paerl HW, Howarth RW, Boesch DF, Seitzinger SP, Havens KE, Lancelot C, Likens
GE (2009) Controlling eutrophication: nitrogen and phosphorus. Science 323:1014-1015
Elmgren R, Larsson U (2001) Eutrophication in the Baltic Sea area. In: Bodungen B, Turner RK
(eds) Science and integrated coastal management. Dahlem University Press, Berlin, pp 15-35
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decades. Ambio 30:222-229
Helsinki Commission (Helcom) (2005) Airborne nitrogen loads to the Baltic Sea. Report, pp 24
HELCOM (2007) Baltic Sea action plan, www.helcom.fi/BSAP/ActionPlan/en_GB/ActionPlan/ .
Accessed 26 November 2010
 
 
 
 
 
 
 
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