Draft:Oxygen depletion in the coastal waters of Denmark

Oxygen depletion in the Danish coastal waters occurs when large amounts of nitrogen and phosphorus accumulate in the ocean. In the summer and fall, this leads to algae blooms that cause oxygen depletion. In oxygen depletion, the concentration of oxygen in the ocean drops to such a low level that animals and plants can be harmed or die.

The excessive amount of nutrients in the coastal areas happens when rainfall and runoffs wash agricultural fertilizer into the Danish coastal areas. In the water, the nutrients feed the growing algae and the water at the bottom can be gradually depleted of oxygen. This process can cause eutrophication, an explosive growth of microorganisms, and create the so called ‘dead zones’. Oxygen depletion is intensified by rising sea temperatures, as oxygen is consumed faster in warmer water and warmer water cannot hold as much oxygen as colder water.

In Denmark, oxygen depletion is defined as situations where the oxygen concentration is <4mg/l and severe oxygen depletion when the concentration is <2mg/l.

In November 2023, an oxygen depletion report was released which made it clear that the level of oxygen depletion in Danish waters is at its highest in many years. This conclusion caused a stir in the debate about environmental legislation and where the responsibility for increased oxygen depletion should be placed.

Conclusions from the oxygen depletion report
Every year at the end of August, September, October, and November, DCE - the Danish Centre for Environment and Energy, Aarhus University, in collaboration with the Danish Environmental Protection Agency, publishes a report on the current state of oxygen levels in Danish waters. The purpose is to provide the public with a summary of where oxygen depletion has been measured and the effects it may cause.

The report reveals that oxygen depletion in the coastal Danish waters deteriorated significantly during September 2023, which makes it the second worst case of oxygen depletion for September since measurements began in the 1990s. The areas in the coastal waters of Denmark that are most affected by oxygen depletion are the Limfjord, Mariager Fjord, the southern Little Belt, the fjords of southeast Jutland, the South Funen Archipelago and the Fehmarn Belt. In many of these areas, the bottom water was anoxic and toxic hydrogen sulfide was released from the seabed. In these areas, a large part of the water volume was affected by predominantly severe oxygen depletion. Dead fish were observed in the Limfjord and the bacteria beggiatoa was observed on the seabed in several zones. In numerous areas, the situation was very critical, especially for bottom-dwelling animals, fish, and plants.

Ecological impacts
One of the biggest challenges in the aquatic environment is the continued inflow of nutrients, including nitrogen and phosphorus, partly in the form of agricultural runoff. The fact that agriculture accounts for over 60% of Denmark’s total land area, and that the agricultural land is located close to coasts and fjords make Denmark particularly vulnerable to nitrogen pollution. These conditions can be harmful to the marine environment.

Benthic animals and plants
The oxygen concentration in the seabed water is of vital importance for benthic plants, benthic animals, and bottom-dwelling fish. Low oxygen levels (4-6 mg l-1) stress the larval stage of some benthic animals and fish, as well as adults of particularly sensitive species. With moderate oxygen depletion (2-4 mg l-1), many fish and more mobile benthic animals move away from affected areas, and during extended periods of severe oxygen depletion (< 2 mg l-1) benthic animals and plants die. Even fish and mobile benthic animals can be exposed to oxygen depletion if wind and currents suddenly move oxygen-poor water from one area to another.

Eelgrass is primarily found in coastal waters as their growth dependents on light. The upright seabed vegetation acts as a stabilizer of the sediment by lowering wave action and by supplying oxygen to the bottom water through their growth.. Lower nutrient concentrations are expected to increase the potential for more benthic vegetation, as it will improve visibility and typically also improve oxygen conditions. Seabed vegetation can therefore indicate the state of the environment in relation to eutrophication. The depth limit of eelgrass is recognized by the European Commission as the biological element in Danish waters that can currently best describe the impact of nitrogen pollution based on a scientifically known causal mechanism.

Scientific consensus
Various environmental organizations and environmental research confirm the urgency and the need for political action. A Danish IPBES report from 2021 states that the overaccumulation of nutrients poses the single biggest threat to the Danish coastal marine environment, and that the Baltic Sea is experiencing massive issues with eutrophication and oxygen depletion. Similarly, the Ocean Institute agrees that nitrogen emissions are a serious threat the marine life, and that the primary contributor is fertilizer from agriculture, which reaches surface waters through runoff from fields.

Marine environmental legislation and regulation
Several intergovernmental organizations dictate the Danish maritime environmental legislation. The European Union is a major player when it comes to environmental legislation and regulation of the Danish coastal waters. In addition, the organizations HELCOM and OSPAR also have an involvement in the regulation of the Baltic Sea and the North-East Atlantic, respectively.

Water Framework Directive
The Water Framework Directive (2000/60/EC) (WFD) provides a comprehensive framework for the administrative structure of planning, implementing measures, and monitoring the aquatic environment. The WFD mandates member states to use their River Basin Management Plans (RBMPs) and Programmes of Measures (PoMs) to achieve good ecological and chemical status, and to prevent deterioration (2000/60/EC, article 4). The Water Planning Act (Lov om vandplanlægning 2013) implements the WFD in Danish legislation, with the aim of improving the Danish marine environment by producing an updated river basin management plan every sixth year.

Marine Strategy Framework Directive
The Marine Strategy Framework Directive (2008/56/EC) (MSFD) was adopted in 2008 as a supplement to the Water Framework Directive. It mandates member states to develop national marine strategies to maintain or achieve ‘good environmental status’. The Directive outlines 11 points to achieve “good environmental status,” including reducing eutrophication.

Nitrate Directive
The European concern to protect the marine environment from agricultural sources of nitrate pollution goes back even further. In 1991, the Nitrates Directive was introduced to prevent nitrate pollution from agriculture by promoting the use of good farming practices. The Nitrate Directive is an integral part of the overarching Water Framework Directive. In the period 1990-2000, nitrogen emissions were reduced by more than 40%, however, during the last 20 years, nitrogen emissions have not been reduced any further.

The political response to DCE’s oxygen depletion report September 2023
In response to the DCE's (the Danish Centre for Environment and Energy) oxygen depletion report from September 2023, the Danish Ministry of the Environment issued a press release in which Magnus Heunicke, Minister of the Environment, calls the situation "alarming" and calls for immediate action. Furthermore, both the importance and vulnerability of the Danish coastal waters are emphasized on the Danish Environmental Protection Agency's website. The agency also emphasizes that the Baltic Sea in particular is vulnerable to human activity, oxygen depletion and eutrophication due to limited water exchange, which can result in the accumulation of nutrients from the hinterland.

Denmark’s struggle for compliance
In 2014, Denmark was found guilty by the European Court of Justice of violating the Water Framework Directive. The judgement was based on the fact that Denmark had not published its river basin management plan for the period 2009-2015 and had not notified the plans to the European Commission in time. The river basin management plan was due on the 22nd of December 2009, but was not published and reported back to the Commission until the 30th of October 2014. This is not the only time Denmark has struggled to meet the requirements of the EU. In 2019, the Danish government once again requested the European Commission to postpone the deadline for improving the marine environment. Since the Water Framework Directive came into force in 2000, the deadline has been extended from 2009 to 2015 to 2021 and the current deadline stands at 2027.

In 2023, the Danish Ministry of Environment announced its latest river basin management plan. Although the government has plans to bring down the amount of nitrogen, mainly from agricultural sources, by 10.400 tons annually, experts in the field are skeptical when it comes to the timeline. According to the Water Framework Directive, the marine environment must be in good condition by the year 2027, which gives the government’s river basin management plan four years to fulfil. The skepticism is based on the fact that only five out of 109 coastal waters are considered to be in "good ecological status", which the EU requires for a member state to comply with the Water Framework Directive. Although many environmental organizations claim that Denmark does not comply with the Water Framework Directive, the Ministry of the Environment still believes that Denmark meets the requirements of the directive. However, the ministry states that the number of areas in "good ecological status" will continue to be five out of 109 in 2027 despite increased efforts to reach the target.

The latest criticism of the Danish government has come from Rigsrevisionen (the National Audit Office), which criticizes the government's management of the marine environment. The State Auditors have declared that Denmark is far from meeting the EU's 2027 requirements for the aquatic environment under the Water Framework Directive, which is the reason why they will examine the Ministry of Food, Agriculture and Fisheries' and the Ministry of the Environment's monitoring of nitrogen emissions and whether it has been sufficient.

The struggle of who to blame
Furthermore, marine environmental policy is characterized by the fact that stakeholders have different interests, which can end up hindering the implementation of environmental policy. While natural science points to agricultural activities as a major cause of the desolate seabed, the organization Bæredygtigt Landbrug (i.e. Sustainable Agriculture) claims that oxygen depletion in Danish coastal waters primarily results from wastewater originating from other Baltic and Nordic countries. Anna Bak Jäpelt, Head of Sustainability at the think tank Frej, believes that the Danish government has failed the farmers and the fishermen by not future-proofing the industries. She believes that the government should have done a better job of helping industries transition to become more sustainable.

Public reaction
In the wake of DCE's - the Danish Centre for Environment and Energy latest oxygen depletion reports for the summer of 2023, the public and the media's attention has intensified.

The public's frustration and sentiment has been expressed through the nationwide protest called "Danmark Holder Vejret". The protest was held at 12:00 on October the 29th, 2023, through local events, demos, and rallies. The purpose of the event was to show sympathy for marine life by holding your breath for 30 seconds. The purpose of the protest was also to raise awareness of the public's demand for environmental action against the government. The message was shared on social media under the #DanmarkHolderVejret

The protest has been launched on the initiative of the Danish Society for Nature Conservation (Danmarks Naturfredsningsforening), the Danish Sports Fishing Association (Danmarks Sportsfiskerforbund), the Danish Sports Diving Association (Dansk Sportsdykker Forbund), the Danish Sailing Union (Dansk Sejlunion) and the Danish Outdoor Council (Friluftsrådet).

A complain to the European Union
The Danish Society for Nature Conservation, Greenpeace, the Danish Council for Green Transition and the Danish Sports Fishing Federation have appealed to the EU concerning the fact that Denmark's nitrogen emissions have not declined over the last ten years and are not expected to decline sufficiently by 2027, the deadline for the EU Water Framework Directive. It is considered by the associations that the lack of reduction in the Danish discharge of nitrogen is in violation of the purpose of the Nitrates Directive (91/676/EEC), which aims to reduce water pollution caused or induced by nitrates (i.e. nitrogenous fertilizers). The Danish nitrogen plans are also considered to be in conflict with the Water Framework Directive (2000/60/EC), which aims to ensure a good aquatic environment by 2027.

The Great Danish Eelgrass Initiative
From 2024, citizens can get involved in the Danish marine environment, by participating in the Great Danish Eelgrass Initiative. The initiative is a new 3-year project based on a ‘big eelgrass day’, where citizens can help to plant eelgrass in the sea. The Ocean Institute is leading the project together with the University of Southern Denmark and has been awarded DKK 8.8 million in funding from the Nordea Foundation. The initiative is a scientific project that contributes to the collection of data on Denmark's eelgrass population via volunteers. In addition, it is a project that involves and mobilizes Danes in a concrete matter of planting eelgrass along the Danish coasts once a year and thus restoring parts of Denmark's marine environment. The first planting day of eelgrass is June 8, 2024, on World Ocean Day.

Focus on the marine environment in the Finance Act
On November 27, 2023, the Danish Finance Act for the year 2024 was passed. It includes funding for an emergency package to improve the aquatic environment and set aside lowland soils. The allocated amount is DKK 405 million, which is to be distributed over four years.