Nature values in oil combating and cleanup
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Photo Vastavalo, Jouko Langen
The effects of oil spills on the
nature of the Baltic Sea
Oil is threatening the nature of
the Baltic Sea
The Baltic Sea is a unique and sensitive ecosystem.
Its special characteristics such as low salinity, small
water volume, restricted connection to the ocean,
seasonality and the ice cover during winter make
it vulnerable to the effects of oil spills. Low-oxygen
conditions and the lack of oil-degrading microbes
cause the oil to remain in the ecosystem for a long
time. Indeed, the International Maritime Organisation IMO has designated the Baltic Sea as a Particularly Sensitive Sea Area (PSSA).
The amount of marine traffic, especially oil transport,
in the Baltic Sea has multiplied during the last few
decades. Even though increasing amounts of resources are allocated to maritime safety, smaller oil
spills occur regularly and it is estimated that larger,
over 500 tonne oil spills occur for example in the
Gulf of Finland on average every 39 years. When
the oil spills into the sea, it causes both immediate
and long-term adverse impacts on the environment.
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Amount of oil transported
(million tonnes)
180
160
140
120
100
80
60
40
20
0
Oil transport in the Gulf of Finland
during 2000-2012. (Source: Centre
for Maritime Studies).
Year
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The Baltic is a unique sea. The shallow water and scattered archipelago create the prerequisites for a diverse nature both above and under the water surface. For the same reasons,
maritime navigation on the area is challenging, which adds to the risk of an oil spill.
Photo: Image bank of the Environmental Administration, Riku Lumiaro
Several species in the Baltic Sea are living there at
the extremities of their area of occurrence, and their
genomes and ecologies can be very different from
that of their ocean or inland water relatives. As a result of an oil spill, some of the unique life forms adapted to the conditions of the Baltic Sea may be lost.
in the Gulf of Finland and the Archipelago Sea. This
geographical information is collected to a database
and map application developed by the project.
In the event of an oil spill, the map application data
can be combined, for instance, with oil spill drift predictions using the BORIS 2 system of the environmental administration, whereupon the information on
which areas are about to be contaminated and what
natural values exist on these areas can be quickly
acquired.
OILRISK attempts to decrease the detrimental effects
caused to nature by a possible oil spill. The project
studies oil sensitive endangered species and habitats
as well as gathers information of their occurrences
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Oil in nature
Oil affects the nature of the Baltic Sea in many ways both on the shores and below the surface. The effects of
oil depend on the amount of oil spilled, oil type, time of year, weather conditions and whether the oil remains at
sea or drifts to the shores.
Very light oils (kerosene, petrol/gasoline)
Light oils (diesel, light crude oils)
Highly volatile
Many toxic (soluble) compounds
Serious local effects to the water column and shoreline
Cleanup not necessary
Spread across the surface
Moderately volatile
Some toxic (soluble) compounds
May contaminate the shoreline
Cleanup very efficient
Medium oils (crude oils)
Heavy oils (heavy crude oils, heavy fuel oil)
Spread across the surface
One third evaporates within 24 hours
Shoreline contamination can be severe and long-term
Birds and mammals in danger
Efficient cleaning possible if conducted quickly
Also go under the surface
Almost no evaporation
Severe shoreline contamination
Great damage to birds and mammals
Contamination of sediments
Cleanup very difficult
Behaviour and effects on nature for various oil types (Source: Helle 2009).
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Seabirds are the most visible victims
Often the most visible victims of an oil spill are seabirds, who spend significant amounts of time on the
water surface or along the shoreline. Birds may alight
on oily water if the oil slick makes the water surface
appear calm. For birds, staining with oil is especially
dangerous. Even a coin-sized oil drop is enough to
break the water-resistant structure of the plumage,
whereupon the bird is in great danger of drowning
or dying from hypothermia. The oil-stained bird often
also tries to preen itself clean, whereupon it digests
oil. The consequences of this include liver and kidney
damages, anemia and weakened resistance towards
pathogens that can lead to delayed mortality.
The majority of damage to the birds can be avoided
with good planning. When the important resting and
nesting sites are known, the birds can be scared off
to prevent them from smothering with oil.
Even though the smothered birds often do get plenty
of public attention, it is important to remember that
oil causes serious problems also to other lifeforms.
Above all, oil spill response resources should be targeted to areas with species, whose significance to
the ecosystem is great or whose recovery from the
accident is uncertain, be they birds, plants, fish or, for
instance insects.
Cleaning of oiled bird is a laboured process. Although Finland is
exceptionally well prepared for cleaning and taking care of oiled birds
compared to other countries, all birds can never be rehabilitated.
Photo: Toni Jokinen, WWF
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Oil effects on the shore
Oil affects shore vegetation primarily by covering
the plants. An oil-covered plant does not receive the
sunlight it needs for photosynthesis and growing. In
addition, oil can block the stomata of the plant and
suffocate the plant. The toxic components of oil,
such as PAH compounds, can also diffuse through
the cell walls or the stomata of the plant and cause
cell damage and growth disorders.
When a major oil spill occurs, it is very probable that
there is not enough time or resources to recover all
the oil at sea, but at least a part of the oil reaches shore. On the shoreline, the oil affects both the
plants and the animals living in the shore and its surroundings.
Photos: Image bank of the Environmental Administration, Jouko Pirttijärvi
The harmfulness of the oil, both on the surface and below it, depends mostly on the geology of the shore. For
instance, open rocky shores are not very sensitive to oil, because they usually have very scarce vegetation,
the oil cannot penetrate into the rock and in addition, the waves can clean the shore by washing the oil back to
the sea. On sand and gravel shores and shores with vegetation on soft soil, oil may penetrate the sediments
of the beach and thus be stored there and influence the area for a long time. The oil sensitivity of the shore
zone is also influenced by many other factors such as the organisms living of the shore and the time of year.
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Even though the parts above ground level would
wither away, a perennial plant may still survive due to
its underground roots, if the oil has not penetrated the
ground surface. Annual plants usually wither away
completely when they are covered with oil, but they
might start growing again with the help of seeds in the
ground or spreading from nearby areas.
Of shore animals, the oil is most dangerous to those
species, whose habitat is small and located near the
waterline. The threatened beetle Aegialia arenaria,
classified as ‘vulnerable’ lives its entire life in the surroundings of sandy beaches or dunes. If the beach
becomes oiled, the poorly mobile beetle can hardly
escape. Even though the shore would later recover
and the food plants of the beetle would return, it is
unlikely that the rare species would return by migration, and the species will not likely occur on the area
anymore.
The threatened beetle Aegialia arenaria lives on the sandy beaches
of the Baltic Sea. Photo: Krister Hall
Mobile animals, such as many adult butterflies, birds
and mammals can move away from the oiled shore
and thereby avoid the danger caused by the oil. The
eggs, larvae and young of species that breed on the
shoreline are most sensitive to the effects of oil. If the
shore becomes oiled in the spring, a whole generation may be lost.
Predators usually move over large areas and can
thus avoid the oil. Oiled prey is however an easy victim that can attract the predators on the oily shore. In
this way oil can be transferred from e.g. oiled birds to
otters and sea eagles.
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Natural sandy beaches are particularly sensitive to the effects of oil. Many endangered species are dependent upon this habitat. The
valuable nature of the shore can also extend underwater. For example, a meadow of common eelgrass can be found on the sand
bottom. Painting: llmari Hakala/Sopiva Design
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Figures: Fiia Haavisto
Oil under the surface
destroyed, or disorders can be caused to the developing fry. Fully grown fish can in most cases avoid
oiling by swimming away from the contaminated
area. Because oil primarily influences the spawn and
fry, it may take several years until the effects of an oil
spill to the fish populations are fully shown.
The biological communities in the coastal waters
have often formed around one key species such
as bladder wrack, common eelgrass or blue mussel, and the disappearance of these species from
the area will create major changes to the entire
biological community. Similarly to on the shore,
when the oil reaches the bottom, it may suffocate or contaminate underwater plant
and animal communities. A layer of oil
on the surface of a plant or alga can
also cause waves to detach the individual from the bottom due to its
increased weight.
Oil spills have been show to have long-term adverse effects on
the European flounder, which lives near soft sea bottom, e.g. because poisonous compounds are accumulated in the bottom sediments. The fry of the European flounder and the turbot live their
first years in shallow waters on sand bottoms and are therefore
particularly vulnerable to oil. Photo: Janica Borg
In the case of invertebrates, it has
been noted that mobile herbivores such
as amphipods and isopods are the first to
disappear from an oiled area whereas shellfish
endure oiling slightly longer by closing their shell.
Invertebrates are an important food source for several fishes and changes in their species abundances
caused by oil contamination can e.g. weaken the
availability of food for fishes.
For fishes, especially the spawning and larval phases are very sensitive to the effects of oil due to the
great sensitivity to the toxic compounds in oil and the
great probability to be exposed to oil. If the spawning
areas are covered with oil, the eggs can be entirely
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A grey seal cub rests on the beach rocks in March. Photo: Mikko Toivola
Marine mammals, such as the grey seal and the Baltic ringed seal living along our coast, are at the top
of the food chain. The thick fat cover and fur of the
seals protect them from hypothermia if oiled. This is
why they are not as sensitive to the effects of oil as
for instance seabirds. Adult seals can often avoid the
oil by swimming away from it, but if they accidentally
swim into oil, their eyes or other sense organs may
become damaged. During winter-spring, seal pups
on rocky islets and ridged ice are in greatest danger of becoming stained with oil. The pups move less
and their thinner fat cover and soft fur do not offer
the same good protection when compared to adult
seals. In addition, the detrimental effects to plants,
invertebrates and fishes in the food chain below are
also reflected on seals of all ages.
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After an oil spill has occurred:
protecting natural values
It is important to react quickly in the case of an oil
spill. In a vessel accident leading to an oil spill, the
primary goal of the response authorities, after lifesaving, is to contain the spill and recover as much oil as
possible at the spill site. However, if the oil spreads
on the open sea towards the coast, valuable locations should be protected with oil booms and coastal
protection sheets. The booms can also be used to
direct the oil to areas that are easy to clean.
Especially in major accidents, there will be situations, where the booms are not enough to ensure
that everything is protected. In this case, the choice
has to be made concerning what areas are protected
first to minimize the harmful effects of oil.
The OILRISK project creates a map application to
make this work easier, in terms of natural values
of sites. On this page a sketch of the prioritisation
scheme used in the map application concerning protection of sites with high nature values can be seen.
In an actual decision-making situation, the rescue
officer can combine this map information with other
data, for instance data of economically and socially
important locations and the location of the oil spill
response resources, and decide upon the final order
of protecting.
The valuation of natural locations should take into
account their conservation value, legislative status,
exposure to oil, ability to recover as well as oil combating efficiency and cleanability. In the following
sections are some examples of terrestrial and marine habitat types that should primarily be protected
from oil.
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Valuable nature in need of
protection
Need for protection
highest
lowest
Painting: Ilmari Hakala/Sopiva Design
Prickly saltworth (Salsola kali)
Endangered species (EN), grows on sandy beaches, oil combating
easy with protective sheets. Photo: Terhi Ryttäri
Eelgrass meadow (Zostera marina)
Endangered habitat (EN), grows on sandy bottoms, underwater target hard to
protect . Photo: Metsähallitus
Common guillemot (Uria aalge)
Endangered species (EN), nests on rocky islets, booming success low due to
mobility of the birds. Photo: Petri Päivärinta
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Shoreline habitats to be protected
make them important nesting sites for several species of birds, such as the northern lapwing and the
common redshank. Especially during the migration
period, geese use sea shore meadows as resting
and grazing places. During the last few decades,
many sea shore meadows have overgrown as a result of e.g. the end of traditional use such as mowing
and grazing, as well as eutrophication causing increased growth of common reed. Sea shore meadows have decrease to one tenth of their amount in
the 1950s, and they have been classified as an extremely endangered habitat. The rich vegetation and
fine soil structure make the cleaning of this habitat
nearly impossible, so it is particularly important to
protect these sensitive and rare localities from oiling.
Natural sandy beaches and sea shore meadows are
examples of terrestrial habitat types that should be
primarily protected from oil contamination. A significant part of the localities of these endangered habitat types are also protected by the Finnish Nature
Conservation Act and EU’s Habitat Directive.
The special characteristics of sea shore meadows
include openness and rich, zoned vegetation, which
In addition to booms, the shores can also be protected with protection sheets. Also common reed
belts can prevent the oil from reaching the shore or
at least slow the oil down. In some cases, the reed
can be cut to protect the shore. When reed is utilised
in oil protection, the effects on species utilising the
reed should be taken into account. For example, a
rare sawfly Hylaeus pfankuchi nests in the plants;
when the reeds are cut, also the nesting places for
the sawfly are removed.
In the archipelago, there are patches of meadow-type vegetation
growing between the rocks on rocky and stony shores. Coastal
processes, such as tide, waves and ice movements keep the vegetation open. European centaury in its full glory.
Photo: Terhi Ryttäri
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Grazing helps to maintain the sea shore meadows open. Sandbottom shore meadow in the outer archipelago, Jurmo island.
Photo: Terhi Ryttäri
Endangered habitats in the OILRISK database
Coastal habitat types
Underwater habitat types
Sandy beaches
Dunes
Sea shore meadows
Wooded meadows and coastal herb-rich forests
Calcareous rock outcrops on seashores
Coastal vegetated moraine, stone and boulder shores
Eelgrass (Zostera marina) meadows
Vascular plant communities
Charophyte meadows
Bladder wrack (Fucus vesiculosus) communities
Flada and glo lakes
The database includes information on the representative localities of oil-sensitive and endangered habitats. In addition to habitat data, the
database also has information on e.g. localities of endangered species, nesting and resting places of water birds and the spawning areas of
the pike-perch and northern pike. As new data concerning oil-sensitive natural values is gathered, it can be updated into the database.
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Underwater nature can be protected
with booms
ows and charophyte meadows. Finland also has a
particular international responsibilty for protecting
these habitats because they have characteristics
unique to this area. Eelgrass meadows and charophyte meadows are sensitive to oil spills as they
grow on soft bottoms in shallow areas.
Underwater nature is hard or nearly impossible to
clean from oil afterwards. This is why preventing the
spreading of the oil to valuable underwater nature
targets with, for instance, booms, is the primary oil
combating method for underwater nature.
Suitable habitats for charophyte meadows include
flada lakes, i.e. shallow bays that have evolved from
the sea as a result of land uplift and that are connected to the sea waters by a channel. Flada lakes
are included in the habitats of the EU’s Habitat Directive, and fladas in a natural state with an area
of less than 10 hectares are
protected by the Water Act.
They are also rich in lifeforms and important living
environments for fish during
the larval phase.
Underwater habitats of our coast that have been
classified as endangered include eelgrass mead-
The rich underwater nature of fladas can be protected by setting booms to
the channel leading to the
flada.
A colorful and diverse world is hidden under the surface of the Baltic.
In this picture grow among others
eelgrass, red algae and blue mussels. Photo: Mats Westerbom
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Sheltered and rich in vegetation, fladas are a favourable environment for many fry and chicks. Photo: Johan Persson, Upplandsstiftelsen
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After an oil spill has occurred: cleanup
Shore cleaning requires a significant amount of workers. The voluntary oil spill response troops of WWF help the authorities to clean
the shore. Photo: Toni Jokinen, WWF
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After the oil spill has taken place, the oil combating
and protection activities are launched immediately if
the weather allows, and the combating at sea usually
last from a few days to a few weeks. The cleanup of
oil-contaminated areas is however a very laborious
process, which, in the worst case, can continue years
after the oil spill. Cleanup activities must be organised. The cleanup phase is not as urgent as the combating phase, and therefore time should be allocated
to careful planning. Poorly planned cleanup activities
can even cause more harm than good.
In addition to considering what is technically and economically most sensible, requirements set by natural
values should also be taken into account in the selection of cleanup methods. For instance for a public beach, the most efficient cleanup method can be
scraping the oiled layer of sand off using a loader.
The conservation of the habitat’s special features
should be taken into account in the case of natural
state sandy beaches. For example, it is forbidden
to destroy or purposefully interfere with a protected
species without specific exceptional permission. For
the endangered species, it is often better to recover
the loose oil carefully and leave some of the oil to be
degraded by nature. Often for delicate areas, the only
suitable method is manual cleaning.
This subspecies of thrift (Armeria maritima ssp. intemedia) is a
critically endangered plant found on sandy beaches of the Baltic
Sea. Removing the protected plant without permission - also from
an oil-contaminated beach - is forbidden by the Finnish Nature
Conservation Act. Photo: Kimmo Inki
The OILRISK project studies suitable and unsuitable
cleanup methods for sensitive areas. The map application also contains recommendations for these
methods. The application does not give recommendations on the cleanup order of areas, but it offers
recommendations on selecting the cleanup method
and planning movement during cleanup. In practice,
it is always recommended to contact the environmental authorities and nature experts when planning the
cleanup of sensitive areas.
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This brochure is a result of the cooperation between the OILRISK and NANNUT projects.
OILRISK – Applications of ecological knowledge
in managing oil spill risk - is a three-year project
(1.12.2009–30.11.2012), which creates a database
of oil-sensitive natural values and a map tool to
support oil recovery and cleanup work. The project
also assesses the costs of cleanup work. The project is funded by EU’s Central Baltic INTERREG IV
A Programme, the Centre for Economic Development, Transport and the Environment of Southwest
Finland, City of Porvoo, Eastern Uusimaa Regional
Emergency Services, City of Kotka, Regional Council of Päijät-Häme, University of Tartu and Centrum
Balticum Foundation’s Protection Fund for the Archipelago Sea.
NANNUT – Nature and Nurture of the Northern Baltic Sea - is also a three-year project that ends in
August 2012. The NANNUT project investigates underwater nature and creates tools that can be used
to take the underwater nature better into account in
planning and decision-making. The project is funded
by EU’s Central Baltic INTERREG IV A Programme,
the Centre for Economic Development, Transport
and the Environment of Southwest Finland, Game
and Fisheries Research Institute, Novia University
of Applied Sciences, Regional Council of Southwest
Finland, Cities of Kaarina, Kotka, Parainen and
Turku, Kemiönsaari, Raasepori, The Åland Government and the University of Stockholm.
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The sea campion grows naturally on gravel, stone or sand on
sea shores and in cracks of sea shore rocks. Photo: Image
bank of the Environmental Administration, Jouko Lehmuskallio
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Additional information:
OILRISK-project
www.merikotka.fi/oilrisk
Project Coordinator Miina Karjalainen
Kotka Maritime Research Centre
Heikinkatu 7
48100 Kotka
tel. +358 44 522 2843
e-mail: [email protected]
NANNUT-project
www.nannut.fi
Project Coordinator Sonja Jaari
Novia University of Applied Sciences/Aronia
Raaseporintie 9
10600 Tammisaari
tel. +358 (0) 447998422
e-mail: [email protected]
Situation awareness system for environmental emergency response BORIS 2
www.environment.fi > Finnish Environment Institute > Projects >
Projects in alphabetical order > Situation awareness system for
environmental emergency response (BORIS 2)
Environmental emergency response in Finland
www.environment.fi/oil
Voluntary oil spill response troops of WWF (in Finnish)
www.wwf.fi/oljyntorjunta
Information on endangered habitat types (in Finnish)
www.ymparisto.fi/luontotyyppienuhanalaisuus
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The contents of this publication represent the authors’ views and the Managing Authority cannot be held liable for the information published by the project
partners.
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