The longThe long waveswaves::HistoryHistory ofof eutrophicationeutrophication

in Tin Tööööllöönlahtinlahti BayBayoverover the 20ththe 20th centurycentury

Simo LaakkonenSimo LaakkonenUniversityUniversity of Helsinkiof Helsinki

QuestionsQuestions

FromFrom macromacro (Ollikainen) to(Ollikainen) to micromicro (Laakkonen)(Laakkonen)FromFrom aa conceptualconceptual studystudy of theof the BalticBaltic SeaSea iningeneral to ageneral to a locallocal casecase studystudy ofof longlong--termtermdevelopmentdevelopmentWhenWhen eutrophicationeutrophication startedstarted in the BSR?in the BSR?WhenWhen eutrophicationeutrophication waswas recognizedrecognized as aas aproblemproblem??WhatWhat waswas donedone toto mitigatemitigate eutrophicationeutrophication??

Oxygen saturationat different samplingsites in the summer1908 (Bergman 1908)

Environmentalcommunication inHelsinki in autumn 1908:

All the main dailynewspapers in Helsinkiinformed their readers ofBergman’s studies.

BergmanBergman’’ss conclusionsconclusions

TheThe reasonreason for thefor the exceptionalexceptional massmass occurrencesoccurrences ofofalgaealgae in thein the innerinner baybay areaarea isis causedcaused aboveabove allall bybydischargesdischarges ofof nitrogennitrogen fromfrom thethe gasgas factoryfactory in cityin citycentrecentreHowHow toto improveimprove thethe situationsituation in Tin Tööööllöönlahtinlahti BayBay??DifferentDifferent proposalsproposals in 1908in 1908--1910: a)1910: a) removalremoval of theof the gasgasfactoryfactory b)b) diggingdigging aa channelchannel betweenbetween thethe seasea and theand thebaybay c)c) enlargementenlargement of theof the waterwater volumevolume of theof the baybay d)d)fillingfilling upup thethe baybay completelycompletely e)e) treatmenttreatment ofof wastewaterwastewaterdischargesdischarges andand removalremoval ofof dischargesdischarges to theto the openopen seaseaareaarea

In 1915-1920 a research programme on the water pollution:- City of Helsinki: funding, hygienic studies- University of Helsinki: botany, zoology- Finnish Institute for Marine Research : hydrography- Polytechnic Institute: chemistry=> White paper on water protection in 1926

The pollution of thesea areaclassified byplankton speciesVälikangas 1926

Phytoplankton of the Töölönlahti Bay (e.g.Oscillatoria agardhii filaments)Ilmari Välikangas, 1926

AA studystudy ofof bottombottom nutrientsnutrients ininTTööööllöönlahtinlahti BayBay in 1936in 1936

AA quatationquatation fromfrom aa studystudy mademade byby thethe StateStateAgriculturalAgricultural LaboratoryLaboratory::

””TheThe bottombottom sedimentsediment of the Tof the Tööööllöönlahtinlahti BayBaywaswas studiedstudied inin depthdepth of 4,7of 4,7 metresmetres. The. The bottombottomsludgesludge wouldwould bebe excellentexcellent toptop soilsoil in ain a fieldfield inintermsterms ofof nutrientnutrient contentscontents..””

A new study was made in 1936 including a study on the bottom fauna of theinner bays by docent of applied limnology H. Järnefelt and professor ofzoology I. Välikangas.

A quotation of the sediment study of the inner bay area:

”General impression: black bottom sludge, very strong smell of hydrogensulphide.” ”Bottom fauna: 0 ”

HowHow toto improveimprove thethe situationsituation in thein theTTööööllöönlahtinlahti BayBay??

Ilmari VIlmari VäälikangaslikangasEnsimmEnsimmääinen,inen, professorprofessor ofofzoologyzoology, made the, made the followingfollowingproposalproposal in 1936:in 1936:

FirstlyFirstly, the, the intrusionintrusion ofof pollutedpollutedwaterwater to theto the baysbays shouldshould bebepreventedprevented..SecondlySecondly,, cleanclean waterwater shouldshould bebepumpedpumped into theinto the baybay viaviafountainsfountains inin orderorder toto aerateaerate thethebaybay andand ’’exhaustexhaust”” thethe massivemassivenutrientnutrient reservesreserves foundfound in thein thebottombottom sedimentssediments..

1936: ”Fish kill and stench”

New fish kill in Töölönlahti Bay 1938

According to a fishery researcher the reason for thefish kill was ”excessive fertilization”.

ProtectionProtection measuresmeasures inin latelate 1930s1930s

MostMost partpart of theof the municipalmunicipal andand industrialindustrial wastewaterwastewaterloadload into the Tinto the Tööööllöönlahtinlahti BayBay waswas removedremoved inin latelate1930s1930sCollectorCollector sewerssewers andand pumpingpumping stationsstations werewere builtbuilt totoremoveremove thethe loadload to theto the easterneastern and western side of theand western side of thecitycityTwoTwo largelarge activatedactivated sludgesludge WWTPsWWTPs werewere builtbuilt inin latelate1930s1930sAlsoAlso otherother thingsthings helpedhelped toto improveimprove thethe situationsituation

WAR:

The first bombings made by Soviet air forces inDecember 1939. The Winter War started when theUSSR attacked Finland.

World War Two decreased production andconsumption ->

Less discharges to water bodies, too.

Polluted

Moderately polluted

Slightly disturbed

Random biological studies: A small-scale study on plankton, Halme & Hurme 1952

TTööööllöönlahtinlahti BayBay in 1950sin 1950s

DueDue toto protectionprotection measuresmeasures andand warwar thethe statestate of theof thebaybay waswas stabilizedstabilized. No. No moremore fishfish killskills tooktook placeplace in thein thepostpost--warwar periodperiod andand massivemassive planktonplankton bloomsblooms werewereoverover..YetYet, the, the problemsproblems werewere notnot overover:: ””GreatGreat amountamount ofofnutrientnutrient saltssalts areare washedwashed into the Tinto the Tööööllöönlahtinlahti BayBay fromfromlandland andand fromfrom thethe bottombottom sedimentssediments.. NotableNotable amountsamountsofof algaealgae emergeemerge alreadyalready inin MayMay: The: The waterwater becomesbecomesbrightbright greengreen andand stillstill in Augustin August waterwater isis eyeeye--catchingcatchinggreengreen..””

TTööööllöönlahtinlahti BayBay sincesince 1960s1960s

•• TheThe statestate of theof the baybay hashas improvedimprovedsincesince 1950s and 1960s1950s and 1960s

•• AA umberumber ofof plansplans toto improveimprove thethe statestateof theof the baybay inin postpost--warwar periodperiod:: nonenone ofofthemthem waswas realisedrealised

•• StudiesStudies werewere restartedrestarted in 1990s,in 1990s,intensiveintensive monitoringmonitoring in 2002in 2002 -->>measuresmeasures in 2005in 2005

HS 22.8.2004

PumpingPumping ofof seasea waterwater into Tinto Tööööllöönlahtinlahti baybay waswasstartedstarted in 2005: thein 2005: the ””channelchannel”” plannedplanned in 1908in 1908waswas finallyfinally builtbuilt

ConclusionsConclusions

InIn citiescities studiesstudies onon euthrophicationeuthrophication for afor a centurycenturyTTööööllöönlahtinlahti BayBay waswas hypereutrophichypereutrophic beforebefore WW II andWW II andconsiderablyconsiderably eutrophiceutrophic in 1960s and 1970s andin 1960s and 1970s and todaytodaymoderatelymoderately eutrophicheutrophichTheThe improvementimprovement hashas happenedhappened mainlymainly becausebecause ofofprotectionprotection measuresmeasures, i.e., i.e. decreasedecrease inin externalexternal loadload thatthathashas takentaken nearlynearly 100100 yearsyearsInternalInternal loadload stillstill aa problemproblemHowHow thisthis situationsituation reflectsreflects thethe situationsituation in the BS?in the BS?