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5 Handling Uncertainty and Sensitivity …
Table 5.8 Summary of assessments or calculations used as basis for classification in the seafloor.
Lag-time and restoration parameters
Main parameter
A: Strength of knowledge (function where it is used)
B: Belief that the value may deviate from the average assumption (Natural
variation of parameter)
C: Sensitivity of function to parameter (sensitivity index)
C threshold,sed
A Moderate strength of knowledge of function
B High
C High
Comments/recommendations:
Concentration of THC at which effects on faunal communities in sediment
cannot be detected in monitoring studies (Renaud et al. 2008). Species may
be more sensitive or less
C benchmark-max,sed A Moderate strength of knowledge of function
B High
C High
Comments/recommendations:
Value representing the maximum value at equilibrium. Based on data from
the MOD data base (North Sea)
20 years def value A Moderate strength of knowledge of function
B High
C High
Comments/recommendations:
Based on MOD data from North Sea, mostly sandy bottom, few sites have
data on restoration times after use of oil-based drilling muds
SF
A Moderate strength of knowledge of function
B High
C High (proportional)
Comments/recommendations:
Theoretical calculation of the leaching of THC from organic carbon,
simplified approach based on physical-chemical properties of THC bound to
organic carbon in sediments (resuspension and redistribution may vary
between substrates and is not included). The SF was introduced to the
function to modify the calculated restoration time
t lag (hard)
A Fixed value
B High
C High
Comments/recommendations:
Very little research available after oil spills affecting deep sea corals.
Comparable incident DHOS not yet restored
(continued)