If implemented, the Baltic Deepwater Oxygenation (Box) project would require around 100 pumping stations built around the Baltic Sea to transport oxygen deep underwater to counteract the declining amounts of oxygen and prevent the growth of the dead zone.

CNN: Can oxygen pump breathe life into ocean 'dead zone?'

Attempts to reduce the waste being dumped into the Baltic have so far failed to stop the growth of the dead zone, now equivalent to around one and half times the size of Denmark.

CNN: Can oxygen pump breathe life into ocean 'dead zone?'

Farmers within a 1.8 mile (3km) protection zone of Cellardyke - where the infected dead swan was found - were ordered to move their birds inside.

BBC: Chicken roast dinner

When teachers guide students in gaining awareness that industrial agriculture writ large, for example, results in chemical runoff from nitrogen-based fertiliers in the Mississippi River that in turn creates a massive dead zone in the Gulf of Mexico so large that it is visible to the human eye through satellite distant imaging, students are able to grasp the basis for sustainable agriculture.

FORBES: Daniel Goleman on the Importance of Ecological Intelligence

Nancy Rabalais, who heads the Louisiana Universities Marine Consortium and has mapped the dead zone each year for nearly three decades, claims that the amount of nitrates flowing into the Gulf of Mexico has increased by up to 300% over that time.

ECONOMIST: Nutrient pollution

But it concludes that the oil is continuing to break up and disperse underneath the surface, making the emergency of a major oxygen-poor dead zone unlikely.

CNN: No signs of 'dead zone' in Gulf, feds say