State of the Gulf of Finland in 2004

(1)

ISO FIMR

MERI

Report Series of

the Finnish Institute of Marine Research

STATE OF THE GULF OF FINLAND IN 2004 Hannu Haahti & Pentti Kangas (Editors)

No. 55 2006

(2)

(3)

MERI - Report Series of the Finnish Institute of Marine Research No. 55, 2006

STATE OF THE GULF OF FINLAND IN 2004

Hannu Haahti & Pentti Kangas (Editors)

(4)

MERI — Report Series of the Finnish Institute of Marine Research No. 55, 2006 Cover photo by Ilkka Lastumäki.

Publisher:

Finnish Institute of Marine Research P.O. Box 2

FI-00561 Helsinki, Finland Tel: + 358 9 613 941 Fax: + 358 9 323 2970 e-mail: surname@fimr.fi

Julkaisija:

Merentutkimuslaitos PL 2

00561 Helsinki Puh: 09-613 941

Telekopio: 09-323 2970 e-mail: sukunimi@fimr.fi

Copies of this Report Series may be obtained from the library of the Finnish Institute of Marine Research.

Available at: http://www.fimr.fi/en/itamerikanta/itamerentila.html

Tämän raporttisarjan numeroita voi tilata Merentutkimuslaitoksen kirjastosta.

ISSN 1238-5328 ISBN 951-53-2839-X

Dark Oy, Vantaa 2006

(5)

CONTENTS

ABSTRACT 3

INTRODUCTION 4

THE ICE SEASON 2003/2004 4

NUTRIENT LOADING 5

HYDROGRAPHY AND OXYGEN CONDITIONS 6

NUTRIENTS 7

MACROZOOBENTHOS 11

PHYTOPLANKTON 13

The vernal period 14

The late-summer period 14

INVASIVE SPECIES 17

FISHING 18

HARMFUL SUBSTANCES 19

Dioxins 19

Sediments 19

Fish 20

Heavy metals in Baltic herring 22

OIL POLLUTION 23

REFERENCES 25

(6)

(7)

STATE OF THE GULF OF FINLAND IN 2004

Hannu Haahti' & Pentti Kangas5 (Editors)

Pekka Alenius', Alexander Antsulevich2, Svetlana Basova3, Nadezhda ^A.Berezina4, Heli Haapasaari5, Andreas Jaanus?, Kalervo Jolmas, Pirkko Kauppila5, Seppo Knuuttilaa, Markku Korhonen5, Jonne Kotta', Ari Laine', Mirja Leivuori', Urmas Lips6, Larissa F. Litvinchuk4, Alexey A. Maximov4,

Alf Norkko', Marina I. Orlova4, Heikki Peltonen5, Jukka Pönni7, Mika Raateoja', Johanna Räsänen5, Simo Salo5, Jouni Vainio', Jenni Vepsäläinen5 & Matti Verta5

' Finnish Institute of Marine Research (FIMR), P.O. Box 2, FI-00561 Helsinki, Finland

2 St. Petersbug State Univ., Depart. of Hydrobiology and Ichthyology, 16 line, 29, 199178, St. Petersburg, Russia

3 NW Administr. of Roshydromet (NW Roshydromet), 23rd line 2a, Vasily Island, 199026, St. Petersburg, Russia

4 Zoological Institute, Russian Academy of Sciences, University Embankment 1, 199034, St. Petersburg, Russia

5 Finnish Environment Institute (SYKE), P.O. Box 140, FI-00251 Helsinki, Finland

6 Estonian Marine Institute (EMI), 10a Mäealuse Street, Tallinn, 12618, Estonia

Finnish Game and Fisheries Research Institute (FGFRI), P.O. Box 2, FI-00791, Helsinki, Finland

ABSTRACT

In the eastern part of the Gulf of Finland the freezing started in mid-December 2003 — approximately two weeks later than usual. In the western and the middle parts of the Gulf of Finland the freezing started at the turn of the year, the average time.

In early March a period of cold weather set in and more new ice formed rapidly. The greatest ice cover of the Baltic Sea — 152 000 km2 — was reached on the 11th of March. When classified by the extent of the ice cover, the ice season 2003/04 of the Baltic Sea was average.

In 2004 the salinity and density stratifications were normal for a part of the year. In the summer there was a clear halocline in the middle of the gulf at a depth of 60 m. Oxygen conditions were poor below the halocline in summer. In the autumn vertical mixing was rather strong, resulting in better oxygen conditions at greater depths. Salinity was rather high, as in 2003, at mid to bottom depths in the central gulf in comparison with the last 10 years.

After some storm events in late December 2003, the water mass from Helsinki eastward was mixed throughout. Phosphate concentrations were, due to effective mixing, unusually high in the surface layer east of Helsinki and varied between 0.71 and 1.42 µcoo1/1 in the whole Gulf of Finland at the beginning of the year 2004.

The state of sea bottoms in 2004 was mostly very poor. The monitoring stations of the open sea generally showed deep water oxygen values below 3 mg/1 and in the deep parts of the western Gulf hydrogen sulphide was measured from near-bottom samples. Oxygen concentrations of the local deeps along the archipelago waters of the northern coast were exceptionally low as well. The poor oxygen conditions were reflected as an almost total absence of zoobenthos both in the open Gulf and along the northern coast. In the shallow easternmost Gulf (Neva Estuary) oxygen conditions were relatively good and benthic fauna was also found there.

The algal biomasses in late summer were clearly higher than the average during the latest decade. The algal community was dominated by mixed communities of the cyanophytes Nodularia spumigena, Anabaena sp., and Aphanizomenon flos-aquae. The dinoflagellate Heterocapsa triquetra was also common. Although the cyanobacterial biomasses were moderately high as early as in late July, surface accumulations at their widest extent were observed only in early August due to the lack of sufficiently long calm periods.

(8)

4 Hannu Haahti & Pentti Kangas (Editors) MERI No. 55, 2006

Herring and sprat are the most abundant species in the Gulf of Finland and they constitute the majority of catches. Herring catches were 30 000-50 000 tons during 1980-2002. However, the catches collapsed in 2003 to c. 10 000 tons and further down to c. 7000 tons in 2004. This collapse was not due to decrease in fishing e.g. because of fisheries management or market factors, but merely due to decrease in fish abundance within the Gulf of Finland.

The number of detected oil spills continued decreasing in 2004 and the number of oil spill detections was smaller than ever, even though the number of flight hours increased and Finland has intensified surveillance by utilising satellites in oil spill detection. Most of the detected oil spills are located along the shipping routes outside costal states' territorial waters.

Key words: Gulf of Finland, hydrography, nutrients, macrozoobenthos, plankton blooms, invasive species, fishing, dioxine, heavy metals, oil, sea ice

INTRODUCTION

This report is a part of the Estonian—Finnish—Russian cooperation concerning the Gulf of Finland. It has been compiled of the research and monitoring results of collaborating institutes. Results which were available at the time of compiling this report were used. For some parameters more time is required for analysing and checking the results. The aim of this report has been to serve the public with fresh information on the state of the Gulf of Finland.

The report will also be found at the website of the Finnish Institute of Marine Research (www.fimr.fi).

THE ICE SEASON 2003/2004

In the eastern part of the Gulf of Finland, in the Bay of Vyborg and off St. Petersburg freezing started in mid-December 2003 — approximately two weeks later than usual. In the western and the middle parts of the Gulf of Finland the freezing started at the turn of the year — at the average time. During December the amount of ice increased slowly and there was only thin fast ice and new ice in the archipelago. In the beginning of January 2004 the weather was cold and new ice was formed along the coast. In mid- January the ice reached Motshnyj in the eastern part of the Gulf of Finland. The end of January was mild and windy. The ice was rafted in the Gulf of Finland. At the same time a brash ice formed at the ice edge.

In early February there were short periods of cold weather during which the ice thickened and new ice was formed in the Gulf of Finland. There was ice from the east to the longitude of Hanko. The end of February was mild and the ice started receding so the ice edge in the Gulf of Finland shifted to the Porkkala—Kalbådagrund—Narva line. At the same time ridges formed in the ice field.

At the beginning of March a period of cold weather set in and more new ice formed rapidly. The greatest ice cover of the whole Baltic Sea — 152 000 km2 — was reached on the 11th of March. When classified by the extent of the ice cover, the ice season 2003/04 of the Baltic Sea was average (Fig. 1).

The Bay of Bothnia, Archipelago Sea and the Gulf of Finland were then totally covered by ice.

In mid-March the weather got milder and the ice receded rapidly. In the beginning of April there was a wide lead in the Gulf of Finland from the inlet of Vyborg Bay to Kalbådagrund and from there to the west the sea was open except for the archipelago.

The ice broke up at the average time: in the western Gulf of Finland after mid-April and in the eastern Gulf of Finland in late April.

The duration of the ice season 2003/2004 was average in the middle parts of the Gulf of Finland. In the eastern Gulf of Finland it was approximately two weeks shorter than average.

(9)

State of the Gulf of Finland in 2004 5

The largest ice cover in the Baltic Sea 1990 - 2004

420000

360000 —

300000 —

240000 — E

180000 —

Average 1990-1999 127 500 k 120000 —

60000 —'

0

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Winter

Fig. 1. The widest ice cover in the whole Baltic Sea during 1990-2004. (Source: FIMR, Jouni Vainio.)

NUTRIENT LOADING

The annual average of the waterborne total phosphorus input entering the Gulf of Finland amounted to 6 800 t and total nitrogen input to 127 000 t over the period 2001-2003. The atmospheric deposition of nitrogen was about 12 000 tin the year 2001 and 10 000 tin 2002 (Fig. 2). The total inputs of both N and P were somewhat higher than in 2000 (6 400 t of total P and 120 000 t of total N). The increase is due to higher inputs from Russia. The total P load from Estonia was equal to that in 2000, and total N load was12 % higher. In Finland the total nutrient loads of both N and P decreased significantly, about 42 % for N and 44 % for P. This is mainly due to the extremely low riverine runoff during the period 2001-2003.

The reasons behind those different trends of nutrient loads from three countries is difficult to explain satisfactorily. The total inflow decreased during the period 2001-2003 in the whole catchment area of the Baltic Sea from more than 16 000 in 2000 to less than 11 000 m3/s in 2003. The N and P fluxes vary considerably from year to year depending mainly on hydrological conditions. During periods of high runoff nutrients are abundantly leached from soil, which increases the loads originating from diffuse sources and natural leaching. In addition to that, riverine nutrient load consists of discharges from sources such as industry, municipal waste water treatment plants and scattered dwellings within a river's catchment area. Quantified input data from all these mentioned sources both in the river catchment as well as from direct discharges into the Gulf of Finland is a prerequisite to interpret long-term data on loads and to evaluate the environmental status and related changes in the open sea and coastal waters.

Since 1980 there has been a reduction of approximately 40 % in the levels of total nitrogen emissions from the HELCOM Contracting Parties. On the other hand, deposition levels have only declined by roughly 15 % during the same time period (HELCOM, 2005). This is due to the fact that the deposition of nitrogen into the Baltic Sea is highly dependent on meteorological conditions, which change from year to year. As a result, reductions in nitrogen emissions do not necessarily lead to corresponding reductions in deposition. However, the atmospheric deposition of nitrogen into the Gulf of Finland

(10)

FINLAND ESTONIA LOADING OF NUTRIENTS TO THE GULF OF FINLAND FROM THE LATE 1980s TO 2002

PHOSHORUS [ton/year]

10000

Late 1992-94 1995 1997-98 2000 2001-03 1980s

NITROGEN [tor/year]

(t—IMI l~ ~ Late 1992- 1995 1997- 2000 2001- 1980s 94 98 03

FINLAND

l I

I

I1-4-1 1--11—"m*

Late 1992- 1995 1997- 2000 2001- 1980s 94 98 03

ESTONIA

nan1-1 I

140000 120000 100000 80000 60000 40000 20000 0

RUSSIA

~

I I

Late 1992- 1995 1997- 2000 2001- Late 1992- 1995 1997- 2000 2001- Late 1992- 1995 1997- 2000 2001- 1980s 94 98 03 1980s 94 98 03 1980s 94 98 03

ATMOSPHERIC NITROGEN [tort/year]

I MI

Late 1992- 1995 1997- 2000 2001 2002 1980s 94 98

140000 120000 100000 80000 60000 40000 20000 0 8000

6000

4000

2000

0

RUSSIA

~

seems to the follow more closely the overall pattern of nitrogen emissions in the Contracting Parties.

The deposition has until the year 2002 decreased by 50 % compared to the level in late 1980s.

Fig. 2. Trends of nutrient loading into the Gulf of Finland from late 1980s to 2003. (Origin of data:

HELCOM, EMEP, SYKE.)

HYDROGRAPHY AND OXYGEN CONDITIONS

In 2004 salinity and density stratifications were normal for a part of the year. In the summer there was a clear halocline in the middle of the gulf at a depth of 60 m. Oxygen conditions were poor below the halocline in summer (Fig. 4). In the autumn vertical mixing was rather strong resulting in better oxygen conditions at greater depths. Just in the beginning of 2004 the oxygen content was over 4 m1/1 near to the bottom even below 100 m depths. The salinity was rather high, as in 2003, at mid to bottom depths in the central gulf (LL7, Fig. 3) in comparison to the last 10 years.

In the northern coastal areas of the gulf the oxygen conditions of the bottom water were low but not alarming. The surface of the sediments, however, were oxygen-free at most of the studied localities.

(11)

D~ Tallinn

Kotka Helsinki _{f D}

. • %Klarnila bay Huovari

•LL3A

• •LL6A LL7

Turku

o•,aQ ~/

I-ran - 0

XXvi

Hanko area

Kotka

D

area

0

Deep water area

St. Petersburg

Near-bottom oxygen levels in summer 2004

Source: FIMR, SYKE

• • •

29°00'

28°00' 30°00'

• •

•

23°00'

22°00' 24°00' 25°00'

ml /I

oe

26°00' 27°00'

•

Longitude (°)

Fig. 3. Sampling sites.

In 2004 the sea surface temperature was normal up to May. In early May the surface temperature was higher than the average but in June and July the temperature was lower than the average. The maximum temperature in the sea surface occurred in early August. In the autumn the temperature was at an average level.

Fig. 4. Near-bottom oxygen levels of the Gulf of Finland in late summer 2004. (Source: FIMR, SYKE, EMI, NW Hydromet.)

NUTRIENTS

After some storm events in late December 2003, the water mass from Helsinki eastward was mixed throughout. Phosphate concentrations were, due to effective mixing, unusually high in the surface layer east of Helsinki and varied between 0.71 and 1.42 µmol/1 in the whole Gulf of Finland (Haahti &

Kangas 2004) at the beginning of year 2004. The nitrate concentration was at the same time at the lowest level since 1994 (January measurements, Fig. 5). In the end of April almost all nitrate was totally depleted in the surface waters but phosphate was still available, on the average 0.55 µmol/l. The increase of salinity and phosphate in the bottom layer together with rapid oxygen decrease indicate that some of the deep waters from the northern Baltic deeps have been transported into the Gulf of Finland.

In the summer nearly all phosphates and nitrates were consumed in the surface layer as usual. At the end of the year 2004 nutrient concentrations were at quite normal levels.

Nutrient concentrations of different coastal areas are given in Figs. 6-8.

(12)

NH4 —PO4 LL7 surface

NO3

—1

— 0.8

= 0.6

— 0.4

— 0.2 10

8 6 4 2

0

O

O i

(o C

—3

O (o C

~ O

i C (o

—3

O O

C C

02 — PO4—NO3 NH4 LL7 bottom

14 12 10 8 6 4

I I I I I

�

•

07 C O) o) co co

(o co (o (o (o (o (o

—3 —3 —) —3 —3 —3 —3

O

C

—co 3

2 7\

0

(f)

O

C

~ co

O O

C

CO

—3

co

C

(o —3

Fig. 5. Nutrient concentrations of surface and near-bottom water in the middle of the open Gulf of Finland. (Source: FIMR, Hannu Haahti.)

(13)

oxygen PO4-P NH4-N N023-N

Huovari, near-bottom

co ö

N N

ö ö ö ö ö ö N co 0 co co N

v v LO LO co co ~ • CO CO co rn o 0 rn rn rn 0) rn co 0) 0) 0) rn co rn co co 0) co co 0) 0) 0) 0) co 0) 0) co co co N

Huovari, surface water ^oxygen

20 N023-N

NH4-N

18 PO4-P

16 14

!!!

12 10

8

6

2

-

. i.

—

/

IL. 4

~

d'

^st LO LO CO CO ~ n co co co 0) O O N N M CO V V

L

\

1_

^,

0) 0) d) 0) 0) m 0) 0) O O 0) 0) O O O O O O O O O O

O O O O O O O O O O O O N N N N N N N N N N

20 18 16 14 12 10

0

Fig. 6. Nutrient concentrations of surface and near-bottom water at Huovari, easternmost Finnish coastal waters. (Source: SYKE, Pirkko Kauppila.)

(14)

1.60 1.40 1.20 1.00 0.80 0.60 0.40

4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 0.00 0.20

0.00

- PO4 NH4 NO2+NO3 Tallinn Bay, coast, surface during year 2004

14.00 12.00 10.00 8.00 6.00--- 4.00 2.00 0.00 2.50

2.00 1.50 1.00 0.50

PO4 NH4 NO2+NO3

Narva Bay, surface during year 2004

v 71- ~

0 0 0

~ >+ c Q 2 m ~

ö ö ö ö ö - ~ N U 0 O

Narva Bay, bottom during year 2004

9 ö ^{ö ö ö ö}

N ~

2 n -' Q u) • 0 0

Q

02 NH4 NO2+NO3 - PO4 12.00

10.00 8.00 6.00 4.00 2.00 0.00

Fig. 7. Nutrients and Oxygen variation in the southern coast of the Gulf of Finland during 2004.

(Source: EMI.)

(15)

Deep 16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 - 0.00

water area in the Russian side of the Gulf of Finland surface

❑ PO4 pmol/I

■ NO3 pmol/I ONH4 pmol/I

1990 1996 2000 2001 2002 2003 2004

Deep water area in the Russian side of the Gulf of Finland near bottom

16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 0.00

1990 1996 2000 2001 2002 2003 2004

❑ PO4 pmol/I

■ NO3 pmol/I

❑ NH4 pmol/I 02 nn I/I

Fig. 8. Mean nutrient concentrations of surface and near-bottom water of the Russian deep water area.

(Source: NW Hydromet, Svetlana Basova.)

MACROZOOBENTHOS

Results from macrozoobenthic monitoring of the coastal basins and open sea areas of the Gulf of Finland indicate an advanced state of degradation of macrofaunal communities (Fig. 9). Of the total 57 sites sampled, 40 sites (70%) were entirely devoid of macrofaunal life and a further 11 sites east of Hanko had very reduced faunal communities. Thus approximately 90% of all the sampled sites in the central and northern parts of the Gulf of Finland were severely degraded.

As in 2003, macrofaunal communities in the coastal region were most severely degraded in the eastern deep basins of Kotka and Hamina, while conditions were slightly better in the west (Fig. 9). Outside the actual Gulf of Finland, west of Hanko peninsula in the Archipelago Sea, healthy macrofaunal communities were more prevalent (Fig. 9). The degradation of macrofaunal communities in the Gulf of Finland is obviously due to recurring periodic hypoxia, which precludes the recovery and development of healthy communities. Despite the advanced state of degradation it should be borne in mind that many

(16)

Occurrence of macrozoobenthos in the Gulf of Finland 2004

RN Muikku Aug 2 -16 SYKE RN Aranda May 25 - 31 FIMR Estonian Marine Institute May - Aug

• no animals

• scantily p moderately

• abundantly

7 05

O

0

•

• • — O

• ® •

O • : ~

• ~•

o

0

S

. •

0

of sites sampled are deeper basins, which are particularly prone to the accumulation of organic material that exacerbates the formation of hypoxia.

Monitoring data from the central and western GoF show that macrozoobenthos is very poor also in the deeper open sea area (Fig. 10). The abundant community that prevailed in the middle of the 1990s has declined due to poor oxygen conditions. The few amphipods (Monoporeia affinis) that could still be found at LL6a in 2003, where absent in 2004. This was due to the re-establishment of stratification after salt-water inflows. These conditions still prevail, preventing macrofaunal recovery.

Macrozoobenthos in the deeper sea areas of the southern Gulf of Finland resembled the situation in 2003. There were practically no macrozoobenthos below 80 m depth except for a few sites characterised by better oxygen conditions. The state of macrozoobenthos along the southern coast is better as compared to the northern coast of the Gulf of Finland. In the shallower areas macrobenthic biomasses were moderate indicating stable and good water quality in the area.

Fig. 9. State of macrozoobenthos in the GoF in 2004. (Data from FIMR, SYKE and the Estonian Marine Institute).

The main features of modern state of macrozoobenthos of the eastern Gulf of Finland were formed in 2003 after the disappearance of bottom animals in deep-water areas because of advection of oxygen- depleted waters from the Baltic Sea Proper. In 2004 macrozoobenthos was practically absent over the most part of area of the gulf (Fig. 10). In areas not affected by oxygen depletion and with abundant bottom fauna, the introduced species (polychaete Marenzelleria viridis and oligochaete Tubificoides pseudogaster) new to the Gulf of Finland within the last 10 years began to play a significant role in the

benthos.

The low animal biomasses in the easternmost Gulf of Finland are seen at Fig. 11.

(17)

::•::•r: r., ~~.~.,.~.,.,.~.,.

o ❖ o. ❖ o•.,;

,

.:.•.•.•,•.•,•.; 1..A...

7

Fig. 10. Macrozoobenthos trends at a deep open sea station in GoF; LL 6a. (Data from FIMR).

Fig. 11. The distribution of bottom areas devoid of macrofauna (biomass less than 0.01 gWW/m2) and strongly impoverished macrozoobenthic communities (0.01-1 gWW/m2) in the open areas of the eastern Gulf of Finland in 2004. (Source: Zoological Institute, St. Petersburg, Alexey Maksimov.)

PHYTOPLANKTON

The year 2004 was distinctive at least due to extremely high, if not recordbreaking springtime and summertime phosphate levels in the surface layers of the Gulf of Finland. Phosphate was not exhausted from the surface mixed layer after the vernal bloom, but only in mid-July. This phenomenon had its starting point in January—February 2003 when there were several inflow events of saline, oxygen-rich water through the Danish Straits into the Baltic Sea. These events pushed the anoxic and nutrient-rich waters of the deep basins of the Central Baltic Proper northwards to the Gulf of Finland. The strong storm events in November--December 2003 mixed the waters of the Gulf of Finland, and significant amounts of phosphate rose up to the surface layer. The extremely high phosphate levels observed in the

(18)

surface water masses in the Gulf of Finland all the way to the summer 2004 enabled the high growth potential of cyanobacteria.

The vernal period

The wintertime algal community was dominated by the dinoflagellate Scrippsiella hangoei, which formed relatively high biomasses in the ice-covered Gulf of Finland between mid-February and mid- March. This species dominated also the vernal bloom period. The spring bloom was an average one in terms of its duration and magnitude, as compared to the latest decade, although it commenced and declined somewhat earlier than usual (Fig. 12).

25 - 20 - 15 - 10 - 5 - 0

•

01 02 03 04 05 CIF 07 08 09 10 11 12

Fig. 12. Annual variation of chlorophyll a (mg m-3) in the Western Gulf of Finland. The green curve represents the average for the years 1992-2003, and the red dots the measurements made in 2004.

(Image: FIMR/Alg@line.)

The late-summer period

The algal biomasses in the late summer were significantly higher than the average during the latest decade (Fig. 12). The algal community was dominated by mixed communities of the cyanophytes Nodularia spurnigena, Anabaena sp., and Aphanizomenon flos-aquae. The dinoflagellate Heterocapsa triquetra was also common. Although the cyanobacterial biomasses were moderately high already in late July, the surface accumulations at their widest were observed only in early August due to the lack of long enough calm periods. Thus, the more prominent cyanobacterial blooms were observed in early August, that is somewhat later than typically observed (Fig. 13).

(19)

~.w ge,ntwYhnusliros /`f Ilanfonhning,lreltutel /EN% Finnish Inslituta of Marino Rosemch

fiu.l.

SYK f:

Risk for blue-green algal blooms

very high high moderate low

0,6

■ 1998-2003 0,5 — ■ 2004 0,4 —

0,3 — 0,2 — 0,1 — 0

Week 24 25 26 27

1^{..- .. I}^I 28 29 30

T I

31 32 33 34 35

June I July I August

Fig. 13. The relative index describing the timing of cyanobacterial bloom observations for 2004 and for 1998-2003. (Image: SYKE/Monitoring of algal blooms.)

In July, limited surface accumulations consisting mainly of Aphanizomenon were observed throughout the Finnish side of the Gulf of Finland, but the most consistent occurrences were formed in the eastern Gulf of Finland (Fig. 14).

Forecast for summer 2004

(variable weather) . . 15* E

68 N

54' N

no surface algae -• increasing intensity

1111111111111111 - 1111111111

ei pinteleväå -• meärä kasvaa

Fig. 14. Left: Cyanobacterial bloom forecast for summer 2004. (Source: FIMR and SYKE).

Right: A satellite compilation image from the 7th

July to 12th August, 2004. (Image: Jenni Vepsäläinen, SYKE.) The scale refers to chlorophyll a concentration.

(20)

.4

^~^{4,6 ,0}

0

IT-pdated on 26th July 2004 by Finnish Institute of Marine Research

60.5-

60.0-

St. Petersburg

59.5-

The toxic species Nodularia increased its numbers towards the end of the month as the water temperature rose. The calm and warm weather type occurring in early August increased the water temperature and allowed surface accumulations to emerge at their fullest. Extensive surface accumulations took place all around in the Gulf of Finland. The maximum coverage of the surface accumulations was reached from the 5t11 to the 8th of August (Fig. 15). Shortly afterwards the blooms were dispersed by the winds.

• No visible plankton aggregates

• Visible plankton aggregates O Clearly 4is ble bloom

• Dense and large vise Worn

~

Fig. 15. The cyanobacterial surface blooms in the Gulf of Finland were at their widest in late July — early August 2004. (Image: FIMR/Alg@line.)

The areal coverage did not give real justice to the actually high cyanobacterial biomasses in the Gulf of Finland because of the lack of long enough calm periods. In consequence, the day-to-day variation in the occurrence of surface accumulations was high. The summer chlorophyll a concentrations of the Gulf of Finland were high in 2004. The highest values were measured in the northern and eastern coasts of the Gulf (Fig. 16).

23 24 25 26 27 28 29 30

Fig. 16. Chlorophyll a isopleth for the Gulf of Finland. The image is based on the Finnish, Estonian, and Russian monitoring data east of 23*E for July—August 2004.

(21)

INVASIVE SPECIES

The northern coasts of the Gulf of Finland. The situation with the benthic polychaete Marenzelleria cf viridis has remained mostly unchanged. The species has been present for more than 10 years and it is currently common in all coastal waters. However, the abundance of the species is relatively low compared to high densities found in other Baltic Sea areas (e.g. Gulf of Bothnia and Gulf of Riga).

The zebra mussel Dreissena polymorpha has continued to strengthen its population in the Finnish eastern archipelago areas but no further spread to the west has been observed. In 2004, successful larval recruitment and settlement was observed at several sites in the Loviisa and Pernaja archipelago.

Zebra mussel seems to especially favour the area affected by cooling waters from the power plant in Loviisa where it forms dense communities on rocks and attached on bladder wrack Fucus vesiculosus.

In this area, adult communities with densities and biomass values up to 28000 individuals and 9.8 kg wet weight per m2, respectively, have been observed.

The number of observations of the Chinese mitten crab Eriocheir sinensis started to decline in Finnish coastal waters, indicating a ceasing of the invasion that occurred in 2002-2003. Single individuals were still occasionally caught in fishing nets but their number remains unclear as this species is not actively monitored.

The southern Gulf of Finland. The abundances of Marenzelleria neglecta have declined to a great extent. The species was not found in the deeper sites of the GOF and its abundances were low at river estuaries. Dreissena polymorpha has not extended its distribution area.

The eastern Gulf of Finland. Three crustacean species, new for Baltic Sea were recorded in 2004. The benthic Ponto-Caspian cumacean Stenocuma graciloides was firstly found in open part of the eastern Gulf of Finland (Antsulevich, unpubl.). Occurrences of the Ponto-Caspian isopod Jaera sarsi is reported from several shallow water localities of the eastern Gulf of Finland (Orlova & al., unpubl.), interestingly this invasion was predicted previously (Nikolaev, 1979). Carnivorous cladoceran Evadne anonyx was discovered as a relatively common contributor to summer zooplankton, that means it has been a cryptic species for several preceding years (Litvinchuk, unpubl.).

Earlier reported from the southern Baltic Sea, the Ponto-Caspian amphipod Chaetogammarus warpachowskyi was first found in the inner Neva Estuary in August and September 2004. The Baikalian amphipod Gmelinoides fasciatus was recorded in coastal zone of Luga Bay; at present this site is the westernmost location of its distribution area in the Gulf of Finland. In different parts of littoral zone the Neva estuary G. fasciatus and the other invasive amphipod Pontogammarus robustoides constituted a major part (more than 40%) in total zoobenthic biomass, reaching 24.8 and 13.2 gWW m-2, respectively (Berezina, in prep.).

The zebra mussel Dreissena polymorpha is still the most abundant invasive species along the northern shore in the eastern Gulf of Finland. Here it dominates in communities at mixed and hard bottoms until 7-8 m in depth, contributing more than 90% of total macrozoobenthos biomass; maximum biomass registered in 2004 reached 3315 g WWm 2. As single adult individual of another invasive freshwater Ponto-Azov dreissenid, D. rostriformis bugensis was found in Vyborg Bay in September 2004 (Orlova

& Kovaltchouk, unpubl.).

In 2004 rather dense populations (biomass up to 20 g WWm2) of Marenzelleria neglecta (formerly M.

viridis) were found on sand and clay bottoms at depth 20-30 m. At some sites M. neglecta became the dominant species forming 70-90% of the total macrozoobenthos biomass. In the deep-water area the gradual expansion of invasive North Sea oligochaeta Tubifccoides pseudogaster has been accompanied by the drastic decline of the native Monoporeia affinis population.

(22)

❑ Estonia

Russia (USSR) El Finland

50

10 - 60

FISHING

Herring and sprat are the most abundant species in the Gulf of Finland and they constitute the majority of catches. Herring catches were 30 000-50 000 tons during 1980-2002 (Fig. 17). However, the catches collapsed in 2003 to c. 10 000 tons and further down to c. 7 000 tons in 2004. This collapse was not due to decrease in fishing e.g. because of fisheries management or market factors, but merely due to the decrease in fish abundance within the Gulf of Finland.

In the Baltic Sea, there has been a considerable decrease in weights-at-age of herring and sprat since the beginning of 1980s. Obviously, a comparable decrease in herring weights-at-age has not occurred in any other herring population (Fig. 11). The changes in average herring weights have been larger in the Gulf of Finland than in the other basins of the Baltic Sea. At present the weights-at-age are at the lowest observed level since the beginning of systematic sampling of commercial herring catches age composition, which started in the 1970s. Although the Gulf of Finland herring is considered to be a part of the Baltic Main Basin stock e.g. in international fish stock assessment and management, there are differences in average weights-at-age between the basins. There has been a slight recovery in herring weights-at-age in the Baltic Main Basin during the last few years, but such a recovery has not occurred in the Gulf of Finland.

0 1 1

O N 't CO CO 0 CO CO CO CO CO 0) O) O) 0) 0) 0) 0)

r r r r r r

III 1 1 1 ., I 1

N d' CO CO O N ei'

00) 0) 0) 0 0 0 0) 0) O) 0) 0 0 0

N— r r r N N N

Fig. 17. The herring catches in the Gulf of Finland during 1980-2004.

(Sources: SYKE, Heikki Peltonen and FGFRI, Jukka Pönni.)

(23)

140

60 40 20 -

I I I i I I I I I

O N cp CO CO O N d (C) CO C) N ~

CO CO CO CO CO O O 0) 0) 0) O O O 0) 0) 0) 0) 0) D7 0) 0) O) O O O O N N N 0

- 6 - 8 10 120 -

100 80

Year

Fig. 18. The average herring weights-at-age (ages 2, 4, 6, 8 and 10) in the catches during 1980-2004 in the Gulf of Finland. (Source: FGFRI, Jukka Pönni and SYKE, Heikki Peltonen.)

HARMFUL SUBSTANCES

Dioxins

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs, dioxins) consist of 210 congeners with one to eight chlorines. Those 17 of them having lateral 2,3,7,8 positions being substituted with chlorine are considered to be of toxicological importance and may cause severe impacts on the ecosystem and on human health. Dioxins were never produced intentionally, but they are minor impurities in several chlorinated chemicals (e.g. PCBs, chlorophenols, chlorophenoxy acids, hexachlorophene), and are also easily produced by burning, if chlorine is present. Municipal waste incineration in poorly controlled conditions is a notorious source of PCDD/Fs and also metal industries are an important source. Pulp bleaching with chlorine gas also produces PCDD/Fs.

The Baltic Sea region is one of the areas most contaminated by persistent organic pollutants (POPs) including PCDD/Fs. The high load of dioxins in Baltic fish has lead to recommendations of restrictions on the use of contaminated fish for human consumption.

Sediments

Verta & al. (2005) compiled recent results of surveys of PCDD/Fs in Baltic Sea sediments from Finland, Sweden and Denmark and merged those with data from earlier published work in the Baltic.

Regional distribution in concentration levels, differences in congener patterns, and temporal changes in sediment profiles were examined. One of the main objectives was to study if any major point sources for different PCDD/F congeners could be identified on a regional scale and based on sediment records.

The survey confirmed the impact of chlorophenol production (Ky-5) at Kymijoki river to the total dioxin levels in sediments in the Gulf of Finland and especially near Kymijoki river estuary (Fig. 19, TEQ). Signatures of one other point (MVC production at Sköldvik) could also be discerned (Isosaari 2004). However, the findings did not support that any of the known point sources would significantly influence those congeners that are most abundant in Baltic herring and salmon. Instead, regional distributions in the Baltic Sea indicate that atmospheric deposition may act as a major source for those

(24)

Before 1995 After 1995

20 Hannu Haahti & Pentti Kangas (Editors) MERI No. 55, 2006 congeners and especially for 2,3,4,7,8-PeCDF (Fig. 19). There was no indication of any major dioxin load from St. Petersburg area (Fig. 19). There were clear indications of declines in sediment levels in some areas, but generally the levels of highly chlorinated PCDD/Fs on the northern coast of the Gulf of Finland were still high as compared with other areas of the Baltic Sea. Major areas with data gaps cover the south-eastern and eastern coastal regions of the Baltic Proper and the southern Gulf of Finland.

Fig. 19. Toxic equivalent of dioxins (I-TEQ) and the concentration of 23478-PeCDF in Baltic Sea surface sediment. (Source: Verta & al. 2005.)

Fish

Dioxins have been measured from the muscle of Baltic herring and Northern pike in Finnish sea areas as part of the monitoring activities of contaminants. The latest results are from Baltic herring in the year 2002.

The concentrations of PCDD/Fs in Baltic herring ranged from 0.5 to 2.8 pg/g fw calculated as ITEQ (Fig. 20). The analyses were made from fish muscle homogenates (30-50 specimens of age from three to five years). No significant differences of concentrations between study areas could be found. The concentrations in the Bothnian Bay (Oulu) were slightly higher than in other areas as also reported in other studies (e.g. Hallikainen & al. 2004). A probable degreasing trend in Kotka region could be observed. Note that analysis of fish muscle gives lower fat percentage and lower dioxin concentrations on fresh weight basis when compared to analyses from whole fish fillet.

(25)

5 4.5 4 3.5

PCDD/Fs / BALTIC HERRING

❑ Kotka

• Turku

❑ Oulu

• 3 rn å 2.5

1 0.5 0

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Fig. 20. Concentrations of PCDD/Fs (pg/g ITEQ fw = 10-12 g for one muscle g fresh weight international toxic equivalent) in Baltic herring muscle in the coastal sea areas of Kotka, Turku and Oulu from year

1993 to 2002.(Source: Hallikainen & al. 2004.)

PCDD/Fs PIKE 0 Kotka

• Kotka*

0 Pori

❑Oulu

,

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Fig. 21. Concentrations of PCDD/Fs (pg/g ITEQ fw) in pike in the coastal areas of Kotka, Pori and Oulu and near Kotka* in Ahvenkoskenlahti bay from year 1992 to 2001. (Source: Hallikainen & al. 2004.)

The PCDD/Fs concentrations in pike ranged from 0.11 to 0.82 pg/g I1LQ fw (Fig. 21). For the analyses have been used fish muscle homogenates, made from 3-5 specimens. Lowest concentrations were been found in Oulu followed by Pori. Highest concentrations were in the Kotka Ahvenkoskenlahti bay at the estuary of the Kymijoki river. As for Baltic herring a slightly decreasing trend could be observed in the Kotka region and may be true in the Pori region as well.

1 0.9 0.8 0.7 rn 0.6 å 0.5

0.3 0.2 0.1 0

(26)

Hanko area 0,045

0,040 Hg mg kg-' w.w.

0,035 0,030 0,025 0,020 0,015 0,010 0,005

0,000 ~ ~

d) 0 ~- N CO d' CC) CD N-CO 0) 0 r N CO d• CC) CO N-CO 0) 0 r N CO d' h 0o 00 00 co c0 00 00 c0 c0 00 a) O) O) 0) O) O) O) O) 6) O) 0 0 0 O O 6) O) O) O) 6) O) O) O) O) O) O) O) O) O) 0) 6) O) O) O) 6) O) 0 0 0 O O r r ... r r r r r r r r r r r .- r r N N N N N

i

Kotka area

Hg mg kg'' w.w.

6) 0 r N Cr) d' LC) CO ~ CO 6) O r N CO d' CC) Co ^I,^{- 00 0) O}^rN CO d' I,- 00 00 CO CO CO 00 CO CO CO 00 0) 0) O) O) O) 0) O) O) O) O) O O O O O O) O) O) O) O) CD O) O) O) O) O) O) O) O) CA 0) O) O) 0) O) O) O O O O O r r r r r c- r r r r r r r r r r r r r r r N N N N N

0,080 0,070 0,060 0,050 0,040 0,030 0,020 0,010 0,000

Heavy metals in Baltic herring

In the Hanko area the mean mercury content in herring muscles has increased during the last two years.

Noticeable is that in those years also the highest variability between the individual muscles (standard deviation 0,0014 and 0,0017 respectively) was noticed. In 2004 the highest measured mercury concentration since 1979 in that sea area were found. In the Kotka area mercury tripled from 2002 to 2003, while it decreased to half of that in 2004. The mercury content was nearly at the same level in the other sea areas of Finland as in the Kotka area in 2004 (Fig. 22).

Cadmium concentrations have been measured from individual herring livers since 1998 at FIMR. In the Hanko area cadmium trend is quite stable, showing slight increase or decrease in concentrations depending on the monitoring year. In the Kotka area variable cadmium contents are measured in Baltic herring livers (Fig. 23). In 2002 a high variability in cadmium content in two year old herrings was evident in the Kotka area, which was noticeable in 2003 in three year old herrings as well. In 2004 the variability between individual herring livers decreased, but concentrations in the Kotka area were slightly higher than in the Hanko area.

Fig. 22. Trends of average mercury concentrations in Baltic herring muscle.

(Source: FIMR, Mirja Leivuori.)

(27)

ZOOZ Ä Z eNlo>i X Maximum

Mean - Minimum

COOZ OiueH

i

6666 0)ue11 000Z oiueH ZOOZ O>lueH

86610)jueH

O 2,50

2,00

1,50

1,00

0,50

0,00

6661 e>110>1 000Z AZ e>r0>{

O

£OOZ A£ e>40>i 1700Z e)go>{

120 -z/

100

80

60 Y

40 -

G3

,j11 __r

104

42

20

,

:_

1996 1997 1998 1999 2000 2001 2002 2003 2004

Fig. 24. Oil spills detected by aerial surveillance in 1997-2004 in the Finnish response region.

Source: SYKE, Heli Haapasaari.)

~

(28)

The new terminals established during the last few years have been build to suit large tankers. For example the maximum ship size for the Primorsk oil terminal is 307 metres long, with 15 metres draught and 150 000 dwt. Due to bigger tanker sizes the number of laden tankers has not increased as rabidly as the amount of annually transported oil has — but as the ship sizes increase, also the risk of very large accidents increases.

Fig. 25. Location of the detected oil spills in 2003.

(Source: SYKE, Heli Haapasaari and Finnish Frontier Guard.)

The overall maritime traffic is increasing rapidly. The amount of oil transported through the Gulf of Finland has also increased dramatically during the last decade; from 1995 to 2004 from 20 tonnes annually to 104 million tonnes annually. The amount of oil transported in the Gulf of Finland may be close to 200 million tons annually as early as 2010, if the planned constructions of new terminals and enlargements of capacities of existing terminals will be accomplished in Russia (Fig. 26).

OIL TRANSPORTATION IN THE GULF OF FINLAND THROUGH MAIN OIL PORTS Oil transportation in years 1995-2003 and estimated development 2004-2005 and 2010 225

200 175 150 c 125 100 75 50 25

0

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 by year 2010 0 Batareynaja ■ Porvoo 0 Primorsk m St.Petersburg ❑Tallinn 0 Vysotsk 0 Others (smaller oil ports)

Fig. 26. Oil transportation in the Gulf of Finland through main oil ports. (Source: SYKE, Heli Haapasaari.)

(29)

REFERENCES

Haahti, H. & Kangas, P. (Ed.) 2004: State of the Gulf of Finland in 2003. — Meri — Report Series of the Finnish Institute of Marine Research 51: 1-20.

Hallikainen, A., Kiviranta, H., Isosaari, P., Vartiainen, T., Parmanne, R. & Vuorinen, P.J. 2004.

Kotimaisen järvi- ja merikalan dioksiinien, furaanien, dioksiinien kaltaisten PCB-yhdisteiden ja polybromattujen difenyylieettereiden pitoisuudet, EU-KALAT. — Elintarvikeviraston julkaisuja 1/2004. Elintarvikevirasto. (In Finnish)

Helsinki Commission 2005: Airborne nitrogen loads to the Baltic Sea. — Helcom Environmental Focal Point Information (EFPI). — 24 p.

Isosaari, P. 2004: Polychlorinated dDibenzo-p-dioxin and dibenzofuran contamination of sediments and photochemical decontamination of soils. — Publication of the National Public Health Institute.

A 11/2004. Kuopio, Finland.

Nikolaev, I.I. 1979: Ecological consequences of unintentional anthropogenic distribution of aquatic fauna and flora. [Posledstvija nepredvidennogo antropogennogo rasselenija vodnoi fauny I flory].

In: Ecological prognistication, Moskow: 76-93. (In Russian)

Verta, M., Salo, S., Korhonen, M., Assmuth, T., Kiviranta, H., Koistinen, J., Ruokojärvi., Isosaari, P., Bergqvist, P-A., Tysklind, M., Cato, I., Vikelsoe, J. & Larsen, M.M. Dioxin concentrations in sediments of Baltic Sea — A survey of existing data. (2005, Chemosphere, Submitted).

(30)

(31)

(32)

m

10I 1r401

~~i~

:~niG~►~~~u~+~r:r~►

1 a

~~

FIMR

Merentutkimuslaitos

Erik Palménin aukio 1, PL 2, 00561 Helsinki puh. (09) 613 941 faksi (09) 323 2970 etunimi.sukunimi@fimr.fi

www.merentutkimuslaitos.fi

Havsforskningsinstitutet

Erik Palméns plats 1, PB 2, 00561 Helsingfors telefon (09) 613 941 fax (09) 323 2970 fornamn.efternamn@fimr.fi

www.havsforskningsinstitutet.fi

Finnish Institute of Marine Research Erik Palménin aukio 1, PO Box 2, Fl-00561 Helsinki, Finland

tel. +358 (0)9 613 941 fax +358 (0)9 323 2970 firstname.lastname@fimr.fi

www.fimr.fi

ISSN 1238-5328 ISBN 951-53-2839-X