BSEP116B Biodiversity in the Baltic Sea - Helcom

100
Oil turnover (millions of tonnes)
Number of detected oil spills
300
250
200
150
100
50
900
800
700
600
500
400
300
200
100
Oil spills
The turnover in oil terminals around the Baltic Sea
has increased steadily during recent years (Figure
6.2.2). Together with the expected increase in
maritime traffic, this means that the risk of a major
oil accident in the area is on the rise. Despite an
increasing preparedness of HELCOM Contracting
Parties, any major oil spill would have severe
impacts in both offshore as well as coastal areas.
The major oil accident of the ship “Prestige” on the
Atlantic coast of Spain in 2002 caused significant
short-term reduction in phytoplankton and zooplankton
biomass (Mendes et al. 2005), reduced
abundance and species richness of littoral invertebrates
(ICES 2007b), and decreased fish reproduction
(Dominguez & Saborido-Rey 2005). It killed or
harmed about 200 000 birds (Zuberogoitia et al.
2006), caused strandings of marine mammals and
0
1997 2000 2001 2002 2003 2004 2005 2006 2007
Figure 6.2.2. Total oil turnover in major Baltic terminals handling
>3 million tonnes (Mt) per year. The line represents the number of
reported accidents for the same time period.
0
1988
1989
Oil turnover
1990
1991
1992
1993
1994
1995
1996
oil spills
1997
1998
1999
Shipping accidents
Figure 6.2.3. Number of illegal oil spills detected by airborne
monitoring 1988–2007. The number of flight hours is shown by the
black line. Based on HELCOM aerial surveillance data.
2000
flight hours
2001
2002
2003
2004
2005
2006
2007
160
140
120
100
80
60
40
20
0
6000
5000
4000
3000
2000
1000
0
Reported shipping accidents
Number of flight hours
turtles (López et al. 2005) and significant egg and
adult mortality of peregrine falcons (Zuberogoitia
et al. 2006). In the Baltic, cascading ecosystem
effects of oil, from phytoplankton to higher trophic
levels, are poorly known, but expected to be
harmful owing to decreased food availability and
increased bioaccumulation of toxic chemicals.
In spite of the dramatically increasing oil transportation,
most oil spills detected in the Baltic are
small illegal or accidental spills (HELCOM 2008b).
However, the cumulative effects of such smaller
spills also have direct harmful impacts. Oiled birds
and mammals suffer from hypothermia or intoxication,
which are particularly lethal to the avian
fauna. Annually, an estimated 100 000–500 000
ducks, guillemots and other bird species die owing
to small oil spills in the Baltic Sea (BirdLife International
2007). Encouragingly, such smaller oil spills
seem to have decreased during recent years, possibly
due to better enforcement (Figure 6.2.3).
Other effects of shipping, including
physical impacts
In addition to oil and nutrient pollution, heavy
shipping has a number of other negative impacts
on marine biodiversity, especially in shallow areas.
Ship-generated water movements reform the
coastal zone (Soomere 2005), circulate nutrients in
the water column thus enhancing eutrophication
(Lindholm et al. 2001), and change species composition
in rock pools (Östman & Rönnberg 1991).
Even structural changes and declines in coastal fish
communities may be linked to increased shipping
through coastal erosion, increased sedimentation
and eutrophication (Rajasilta et al. 1999).
Maritime traffic is also a significant producer of
marine litter, even though the amount of litter is
smaller in the Baltic Sea than in some other parts
of the world (HELCOM 2007e). Ship hulls, as well
as ballast water and sediments, transport alien
organisms to the Baltic Sea (see Chapter 6.7, Alien
species) and anti-fouling chemicals used on ship
hulls cause acute effects on organisms, especially
at lower trophic levels of the food web (see
Chapter 6.6, Hazardous substances).
Although maritime traffic considerably increases
noise both underwater and above the surface, it
has not been found to cause acute harm to marine