Project Digitalisation of Ecological Monitoring (DEM)

Human activities, climate change, and transitions with regards to energy, food, and nature are leading to changes in the North Sea ecosystem. A healthy and resilient North Sea is of importance to all of us. To safeguard the ecological carrying capacity of the North Sea, insight into its changing ecosystem is essential. Monitoring is crucial in this respect. With the project Digitalisation of Ecological Monitoring (DEM), the Dutch government aims to make ecological monitoring more effective, sustainable, and easier to implement. This initiative is future-oriented and complements ongoing research and monitoring programmes.

Knowledge gap

Project DEM supports the (statutory) tasks of Rijkswaterstaat in reporting on the ecological status of the North Sea. The collected and processed data will support research and monitoring within the Monitoring and Research Programme for Nature Enhancement and Species Protection (MONS) and the Offshore Wind Ecological Programme (Wozep). In addition, the data will support Marine Strategy Framework Directive (MSFD) reports.

Project objectives

The aim of Project DEM is to innovate and digitalise ecological monitoring in the North Sea.
To achieve this, Project DEM will:

Develop monitoring buoys equipped with a wide range of sensors to generate a continuous time series of multiparameter measurements in the water column at four monitoring sites.
Develop a Data Management System (DMS) to process collected data autonomously and to monitor data quality, so that raw data can be made available as quickly as possible for ecosystem analyses and model validations.
Establish an expert group to provide scientific support with the development of the monitoring buoys and the DMS.
Innovate bird and marine mammal monitoring using image recognition through artificial intelligence.
Invest in innovative techniques for ecological monitoring at sea.

Rijkswaterstaat (RWS) Central Information Services (CIV) under the programme Information Services at Sea (IV op Zee), commissioned by the Ministry of Agriculture, Fisheries, Food Security and Nature (LVVN).

Project planning

Timeline of the DEM project from 2024 to 2028 with different phases and activities. In 2024 the phase ‘needs assessment’ begins From 2024 to 2025 runs the phase ‘defining development questions’. From 2025 onwards, research projects are initiated; this is the current phase, highlighted in green. Also in 2025: ‘preparation of tenders’, followed mid-2025 by the ‘tendering period’. In 2026 the ‘design and construction of buoys’ phase starts. From 2026 to 2028 the research phase runs. From 2027 onwards, monitoring intervals of the buoys are carried out, shown as a sequence of orange and yellow dots continuing until 2028. Each dot represents one month, with each year beginning and ending with a period of two consecutive months. In 2028 the evaluation takes place. The timeline shows that several activities partly overlap: needs analysis and development questions at the start, tenders and design in the middle, followed by research, monitoring and evaluation in the later years. — Project planning DEM

12/2023 Approved project mandate, assignment from LVVN to RWS: project in preparatory phase.
09/2024 Finalisation of requirements, monitoring methods, and project approach: project enters implementation phase.
10/2024 – 2025 Preparation and execution of European tender procedures,award and commissioning.
2026 Construction and commissioning of offshore monitoring buoys, commencement of research projects.
2027 – 2028 offshore monitoring and completion of research projects.

Timeline from 2025 to after 2035 with four trajectories. First trajectory: preparation starts around 2025 and runs until mid-2029. Second trajectory: implementation from about 2028 until after 2035, with no specified end. Third trajectory: DEM starts in 2025 and runs until mid-2028. After that, DEM is expected to continue uninterrupted until after 2035. Fourth trajectory: exploitation starts mid-2030 and also continues until after 2035. — DEM within Jerico 2025-2037

Monitoring buoys

Pairs of monitoring buoys will be deployed at four monitoring station in the Dutch North Sea. These buoys will generate continuous time series of multiparameter measurements. Each pair consists of a string buoy and an ecology buoy.

String buoy

A smaller buoy with sensors positioned at different depths. The string buoy measures parameters that provide insight into primary production and stratification (Chl-A, cDOM, CTD, DO, hyperspectral light, PAR, turbidity). In addition, underwater sound will be recorded using a Passive Acoustic Monitor (PAM) hydrophone, and fish tags will be received via a fish tag receiver.

Ecology buoy

A larger buoy with more electrical power and advanced sensors near the water surface. The ecology buoy measures abiotic factors (ADCP, Chl-A, cDOM, CTD, DO, LDPSA, turbidity). Primary production and the plankton community are also examined in detail using STAF and flow cytometry (FCM).

In addition, a simple weather station will be installed above the water, incident light (PAR) will be measured, and bird and bat tags will be received using a Motus Wildlife Tracking System.

Monitoring stations

Map of the Netherlands and the Dutch Continental Shelf (DCS) with measurement locations and connections. Several colored areas are shown: blue areas indicate existing wind farms, white areas indicate planned wind farms, and green areas indicate Natura 2000 protected areas. There are four yellow measurement locations with buoys: Terschelling 135, German Bight, Noordwijk 10 and Walcheren 20. Purple and yellow lines mark FerryBox routes. Three yellow routes represent the vessel Connector and are long, uninterrupted, and extend beyond the NCP. The purple routes represent the vessel Zirfaea. These are shorter, far more numerous, crisscrossing in many directions, remaining relatively close to the Dutch coast, mostly within the DCS, and together form roughly a capital ‘L’ rotated by 140 degrees. — Locations of DEM monitoring stations in the North Sea

Noordwijk (10 km offshore, 20 m depth): Rhine plume, historical dataset from CEFAS monitoring buoy.

Walcheren (20 km offshore, 20 m depth): Borssele wind farm.

German Bight (35 km offshore, 20 m depth): Oyster reef restoration.

Terschelling (135 km offshore, 48 m depth): Oyster grounds, wind energy search area, low oxygen concentrations near the bottom, ships equipped with FerryBoxes pass through, historical dataset from CEFAS monitoring buoy.

Data management

For the vast amount of data to be collected, an automated Data Management System (DMS) is being designed. Data will be made accessible in line with the FAIR principles (Findable, Accessible, Interoperable, and Reusable).

This will be achieved by testing data quality, adding metadata, and comply with national (AQUO) and international (SeaDataNet / EMODnet) data standards.

To convert raw data into usable data for ecosystem analyses and model validations, six phases are defined:

Acquisition,
Storage,
Technical data quality control,
Expert data quality control,
Standardisation,
Dissemination.

Scientific support from expert group

Group photo of ten adults posing together outdoors in front of a building with wooden slats. They stand on a terrace by the water, with green trees and an office building in the background. The sky is blue with light clouds and the sun is shining, giving a summer-like atmosphere. The group consists of six women and four men, dressed in smart casual clothing such as blouses, blazers, shirts and a T-shirt. They stand close together, some smiling at the camera, and form an expert group photographed for the DEM project. — From left to right: Mainah Folkers (RWS), Laura Dinkla (RWS/Aqitec), Ivo Wieling (RWS/Aqitec), Kees Borst (RWS), Sarah Rautenbach (Deltares), Anouk Blauw (Deltares), Arthur de Waard (RWS), Nicole Dijkman (RWS), Joris Diehl (RWS), Erik Hendriks (Deltares). Attending online: Jef Huisman (UvA) and Dick van Oevelen (NIOZ).

Project DEM has initiated an expert group to provide scientific support for the development of the monitoring buoys and the data management system. The expert group is a collaboration between Rijkswaterstaat (RWS) and research institutes, initially Deltares, the Royal Netherlands Institute for Sea Research (NIOZ), and the University of Amsterdam (UvA) have joined.

The group has expertise in the biological, chemical, and physical climate of the North Sea. In addition, the experts have spezialised knowledge of the operation and deployment of specific sensors.

The expert group will advise on:

Placement and settings of sensors on the monitoring buoys.
Sensor calibration and sensor validation.
Data quality control and validation.
Qunatifying primary production in carbon units.
Estimating chlorophyl-A concentration from fluorescence measurements with less frequent in situ water samples.
Deriving phytoplankton biovolume from imaging flow cytometer data.
Compliancy with the Joint European Research Infrastructure for Coastal Observations (JERICO-RI).

Bird and marine mammal monitoring using artificial intelligence

Currently, birds and marine mammals above the North Sea are monitored by human observations from aircraft as part of the Dutch national long term monitoring called Monitoring Waterstaatkundige Toestand des Lands (MWTL). However, due to the construction of wind farms, the flying altitude above the North Sea will be raised, making human observations increasingly challenging. Therefore, project DEM is investing in the development of a model that can autonomously identify and annotate birds.

Aerial photo of a blue sea surface with nine dark, flying birds visible. The flight direction is from bottom to top. Each bird is marked with a green square or rectangular frame with yellow corners, indicating automatic detection. The flying birds - black scoters (Melanitta nigra) -form roughly an equilateral triangle in the center of the image. — Detected and identified common scoters

This investment focuses on improving a model developed in the project Artificial Intelligence for recognising megafauna (seabirds and mammals) in and around offshore wind farms (AI-MEG) of Wageningen Marine Research (WMR). This will enable more bird species to be identified with greater reliability.

An additional focus will be placed on protected bird species such as the common guillemot. For this purpose, more aerial video footage will be collected covering the North Sea, with a finer grid in the coastal zone, in Natura2000 areas, and in wind energy search areas. Flights will be carried out in parallel wherever possible to compare human observations with automated image recognition, thereby preventing a trend break in bird monitoring. Ultimately, consideration will be given to how the new bird monitoring method can be implemented within MWTL at Rijkswaterstaat.

Investing in innovative techniques for water quality analysis and ecosystem monitoring

Project DEM intends to make financial and material contributions to the proposal for a Large-Scale Research Infrastructure (LSRI) called AQUASYS. Project AQUASYS is a collaboration between Naturalis, the Netherlands Institute of Ecology (NIOO-KNAW), NIOZ, Leiden University, the University of Twente, and the University of Amsterdam.

Project AQUASYS aims to develop innovative methods for water quality analysis and ecosystem monitoring. For Project DEM, the focus will be placed on:

Plankton imaging: advanced image recognition for the identification and quantification of plankton populations.
Vertical profiling: using sensors for water quality measurements in the water column.
Environmental DNA (eDNA): molecular techniques to monitor biodiversity and species composition in aquatic ecosystems.
Smart maintenance: intelligent maintenance systems for more efficient and sustainable management of sensors.

These technologies will be developed for broad applicability and a high technology readiness level (TRL). Project DEM will make a material contribution by making a test buoy available for research. This should enable future implementation within Rijkswaterstaat and contribute to more accurate and efficient ecological monitoring.