One Molecule to Find Them: Using eDNA to Quantify and Assess Marine Biodiversity at Offshore Wind Farms
(2025) BION03 20242Degree Projects in Biology
- Abstract
- The growing number of offshore wind farms being constructed in the North Sea raises important questions about their potential ecological impact on marine communities. Monitoring these effects requires tools that can accurately describe biodiversity, not just in terms of species presence, but also their relative abundance. Environmental DNA analysis is a promising approach for this purpose, but the quantitative application of this method remains challenging due to technical biases introduced during DNA amplification.
In this study, we estimated the amplification efficiencies of 16 commonly found fish species in the Danish North Sea and applied a statistical model to correct for these biases. Water samples were collected at various... (More) - The growing number of offshore wind farms being constructed in the North Sea raises important questions about their potential ecological impact on marine communities. Monitoring these effects requires tools that can accurately describe biodiversity, not just in terms of species presence, but also their relative abundance. Environmental DNA analysis is a promising approach for this purpose, but the quantitative application of this method remains challenging due to technical biases introduced during DNA amplification.
In this study, we estimated the amplification efficiencies of 16 commonly found fish species in the Danish North Sea and applied a statistical model to correct for these biases. Water samples were collected at various distances from the Horns Rev 2 offshore wind farm, from both hard (scour protection) and soft sediment habitats. Community differences were analysed using multivariate statistics.
Using the model to correct the metabarcoding reads improved the explanatory power of the analyses and clarified group differences. For example, herring and other clupeid species exhibited higher amplification efficiencies, whereas cod and wrasses showed lower efficiencies. Community composition differed between the interior and exterior of the wind farm, as well as between different types of substrates. Notably, sandeel occurrence increased near the turbines, while sand goby detection decreased. Despite being a native species, Atlantic cod were not detected in large numbers.
This study demonstrates that using a model to correct data improves its ecological value. This approach can improve biodiversity assessments at offshore wind farms, and it has potential applications in conservation monitoring and fisheries management. However, further development is required, including more extensive testing, to improve precision and expand its use in marine environments. (Less) - Popular Abstract
- CSI: North Sea – Amplifying whispers
Imagine a crime scene with just a trace of blood or a strand of hair – enough for forensic scientists to identify the perpetrator using DNA. The same principle applies to DNA left behind by organisms in an environment. By analysing it, we can identify which species were present at a site and use this to assess ecosystem health. However, to get a full picture, we also need information on abundance, age and size. While it is difficult to extract this information from DNA, this thesis explores how to estimate fish abundance using the DNA they leave in the environment.
Because DNA concentrations in nature are low and difficult to detect, we first multiply it using a process known as PCR, which many... (More) - CSI: North Sea – Amplifying whispers
Imagine a crime scene with just a trace of blood or a strand of hair – enough for forensic scientists to identify the perpetrator using DNA. The same principle applies to DNA left behind by organisms in an environment. By analysing it, we can identify which species were present at a site and use this to assess ecosystem health. However, to get a full picture, we also need information on abundance, age and size. While it is difficult to extract this information from DNA, this thesis explores how to estimate fish abundance using the DNA they leave in the environment.
Because DNA concentrations in nature are low and difficult to detect, we first multiply it using a process known as PCR, which many may be familiar with from the COVID-19 pandemic. Just as every person has a unique fingerprint, each species has a unique DNA sequence, that allows us to identify it. However, there is a catch: PCR is not perfect. Some species’ DNA multiplies more effectively than others, making it difficult to estimate the original DNA concentrations and thus the number of individuals. This is why we are working to understand how well the DNA of different species replicates.
We created mock samples with known fish species and DNA concentrations. With the help of some brilliant bioinformaticians, we determined how effectively the DNA of 16 native Danish North Sea fish species amplifies. This method allowed us to estimate their relative proportions at various sampling sites within the Horns Rev 2 offshore wind farm and explore two key questions:
1. Do fish species and their abundance differ inside and outside the wind farm?
2. Does the introduction of hard surfaces, like the concrete foundations, affect the fish species present and their abundance?
The answer to both is: Yes! We found clear differences in fish species and their abundance both inside and outside the wind farm. Their diversity and abundance were also affected by the concrete structures. Offshore wind farms can have a variety of environmental effects. Whether these are generally positive or negative remains to be seen. Some of the positive effects of wind farms that may have influenced diversity and species abundance at Horns Rev 2 include providing shelter from currents and predators, increasing food availability, and providing nursery grounds for young fish.
In conclusion, this method is suitable to making accurate abundance measurements and improving ecological value. It could also be used for conservation, fisheries management, and controlling invasive species in the future.
Master’s Degree Project in Biology 60 credits 2025
Department of Biology, Lund University
Advisor: Einar Eg Nielsen, Magnus Wulff Jacobsen, Johanna Sjöstedt and Sara Maggini
Lund University, Technical University of Denmark (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9212824
- author
- Berger, Helen
- supervisor
- organization
- course
- BION03 20242
- year
- 2025
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9212824
- date added to LUP
- 2025-09-19 09:40:01
- date last changed
- 2025-09-19 09:44:58
@misc{9212824,
abstract = {{The growing number of offshore wind farms being constructed in the North Sea raises important questions about their potential ecological impact on marine communities. Monitoring these effects requires tools that can accurately describe biodiversity, not just in terms of species presence, but also their relative abundance. Environmental DNA analysis is a promising approach for this purpose, but the quantitative application of this method remains challenging due to technical biases introduced during DNA amplification.
In this study, we estimated the amplification efficiencies of 16 commonly found fish species in the Danish North Sea and applied a statistical model to correct for these biases. Water samples were collected at various distances from the Horns Rev 2 offshore wind farm, from both hard (scour protection) and soft sediment habitats. Community differences were analysed using multivariate statistics.
Using the model to correct the metabarcoding reads improved the explanatory power of the analyses and clarified group differences. For example, herring and other clupeid species exhibited higher amplification efficiencies, whereas cod and wrasses showed lower efficiencies. Community composition differed between the interior and exterior of the wind farm, as well as between different types of substrates. Notably, sandeel occurrence increased near the turbines, while sand goby detection decreased. Despite being a native species, Atlantic cod were not detected in large numbers.
This study demonstrates that using a model to correct data improves its ecological value. This approach can improve biodiversity assessments at offshore wind farms, and it has potential applications in conservation monitoring and fisheries management. However, further development is required, including more extensive testing, to improve precision and expand its use in marine environments.}},
author = {{Berger, Helen}},
language = {{eng}},
note = {{Student Paper}},
title = {{One Molecule to Find Them: Using eDNA to Quantify and Assess Marine Biodiversity at Offshore Wind Farms}},
year = {{2025}},
}