DAGA 2020 Hannover 
Monitoring and Assessment in Regard of Technical Sound Mitigation Developments 
— a Perspective from MarinEARS 
Carina Juretzek, Ben Schmidt, Maria Boethling 
Federal Maritime and Hydrographic Agency (BSH), 20359 Hamburg, E-Mail: Carina.Juretzek@bsh.de 
Introduction 
Underwater sound is incessantly generated in the global 
oceans by a variety of acoustic sources. Wind, waves, sea ice 
and sediment movements are only some of the natural 
processes which form the underwater soundscape. A wide 
range of additional sounds is produced by several marine 
species for different purposes such as communication and 
foraging. But also human maritime activities contribute to 
the ocean’s soundscape. Anthropogenic noise emissions may 
oe characterized inter alia according to their intensity, 
frequency content and signal duration. A distiction between 
continuous and impulsive noise is commonly made when 
decribing the noise emission of persistent sources such as 
shipping.versus the emission of impulsive sources such as 
generated by Sseismic sSurveys or at some Ooffshore 
construction sites. Due to the fact that many marine animals 
rely on sound for vital functions, there has been an increased 
awarenenss of scientists, law makers, governmental agencies 
and the public regarding potential impacts of anthropogenic 
underwater noise on the marine environment. 
The Federal Maritime and Hydrographic Agency (BSH) is 
the authority responsible for the approval of offshore wind 
energy projects in the German Exclusive Economic Zone 
(EEZ), for monitoring and assessment of related underwater 
noise effects on the marine environment and for the 
implementation and operation of the national noise registry 
covering the German waters in the North Sea and Baltic Sea. 
As technical and scientfic support for these tasks, the 
dedicated expert information system MarinEARS (Marine 
Explorer and Registry of Sound) was established in 2016 at 
BSH. MarinEARS provides the backbone of the national 
noise registry, serves BSH as scientific platform for 
monitoring and assessment of underwater noise effects, 
enables the E-Reporting of offshore wind farm (OWF) 
monitoring data in the context of approval procedures and 
offers publicly accessible information including the location, 
date and duration of underwater noise events as well as on 
he application of noise abatement systems. 
Here, we introduce the expert information system 
MarinEARS, unfold the extend of the comprehensive data 
oasis and present the content and range of products available 
for the public. Further, we outline its role and capacity for 
regulatory and scientific purposes on national and regional 
level. 
Monitoring of Underwater Noise 
The expert information system MarinEARS is in operational 
service since 2017 and provides BSH with the necessary 
scientific platform regarding underwater noise effects for 
conducting Environmental Impact Assessments (EIA) in the 
framework of approval procedures for offshore wind energy 
projects as well as for the estimation of cumulative impacts 
in Strategic Environmental Assessment (SEA) for Maritime 
Spatial Planning and the Site Development Plan for Offshore 
Wind Energy. Regarding the German EEZ of the North Sea 
and the Baltic Sea, a major source of impulsive 
anthropogenic sound is pile driving during the construction 
of offshore energy projects. As of 2019, 24 OWF“‘s have 
been successfully installed in the German EEZ. Importantly, 
the input of impulsive sound due to pile driving activities 
during OWF construction has to be technically mitigated, 
monitored and evaluated according to requirements of the 
BSH as responsible agency for the approval and monitoring 
of OWF‘s. 
In order to avoid a temporal threshold shift (TTS) in harbour 
porpoises as the key species due to pile driving activities [1], 
the compliance with a sound pressure level threshold 
criterion has been a requirement for all wind farm 
construction projects in the German EEZ approved by BSH 
since 2008. The relevant metrics for the evaluation of pile 
driving noise in this context are the sound exposure level 
(SEL) 
T2 2 
SEL = 10 log4o = Pa [dB re 1 uPaZs] (1) 
Tosr, Do 
and the zero-to-peak sound pressure level (Lynx) 
Lppk = 20 1o0g40 ra [dBre1uPa] (2) 
0 
where T; and T-‚, indicate the start and end of the evaluated 
time span respectively, To is commonly defined as 1 s and po 
is defined as 1 uPa. The impulsive noise emissions from pile 
driving at a measuring distance of 750 m to the piling 
location must not exceed the dual threshold criterion given 
by 
a non-frequency weighted SELos of 160 dB re 1 
uWPa’s, 
a zero-to-peak sound pressure level L,.„x of 190 dB 
re 1 uPa. 
Here, the SELos describes the sound exposure level, 
exceeded by 5% of the total number of measurements. 
Since 2011, the application of technical noise abatement 
systems has been mandatory at offshore construction sites in 
the German EEZ. The compliance with the threshold criteria 
is rigorously monitored according to the measuring 
instructions of BSH [2] and international measuring 
standards [3]. The monitoring data and corresponding 
technical data on noise abatement systems are delivered to 
BSH via the E-Reporting portal of MarinEARS, where they 
are subject to a comprehensive internal quality assurance 
before they are made available for further assessments. 
Underwater noise data can be further processed with 
TS