26 
van Bernem - Marine Sensitivity Aspects 
Figure 5.1: Example of the sensitivity model used by the HK. Increasing sensitivity is marked by the col 
ors ’’green” to “magenta”. The scale on the left allows selecting different topics of the underlying data 
base (for example: different seasons, saltmarshes, seagras, aerial images). The bar on top offers i.a. the 
selection and focus of areas. 
Dealing with uncertainty 
With regard to the reasons mentioned above, there is no conclusive way to soundly define 
the usefulness of chemical dispersants in a particular environment with different temporal 
and spatial conditions. Appropriate scenarios for individual cases have to be evaluated dur 
ing a comparative analysis of the risks and benefits. 
A fundamental goal for oil spill response holds: minimize the ecological impacts of a spill 
(Lindstedt-Siva, 1991). The decision as to whether it is better to protect sensitive habitats - 
rather than to optimize cleanup, needs a specific methodology to optimize all possibilities of 
response into an integrated program. In this concern a “Net Environmental Benefit Analysis” 
NEBA, (Baker, 1995) based on an ecological risk assessment approach can serve as part of 
integrated precaution measures. 
By the way, aside of ecological and natural protection viewpoints, oceanographic and socio 
economic features as well as logistic considerations play an important role in defining a com 
prehensive NEBA study. Hence it needs an integrated approach of natural scientists, 
„coastal users“ like fishery and tourism managers as well as natural protection agencies, oil 
spill response operators and other stakeholders to establish extensive strategies for decision 
finding. 
The basic activities to establish an ecological risk assessment in the first instance can be 
summarized in three phases: problem formulation, analysis, and risk characterization (US 
EPA, 1992a). Within these phases quantitative as well as qualitative data may be used de 
pending on the state of knowledge about the systems involved. The uncertainty of data and 
methods has to be defined as far as possible before the resulting information can be incorpo 
rated into conceptual or mathematical models. Another key element as prerequisite to devel 
op decision strategies is the identification of clear and consistent endpoints related to the 
protection of resources. 
Applying these briefly depicted features to the environment at risk, the Wadden Sea, we can 
establish the following characteristic aspects to define the limits for a selection of possible 
scenarios which meet the basic question: