You know that feeling when you’re held under by a double overhead set, scrambling to get your head above water and out of the break zone… This claustrophobic, oxygen-starved panic is being forced upon countless species of fish, corals, crabs and everything else found living below the waterline. This is the dead zone – and it’s killing us.
Article by Sean Kelly
What is an ocean dead zone?
The name ‘dead zone’ itself paints a pretty accurate picture on what’s going on below the surface. Ocean dead zones, or hypoxia, are low-oxygen areas that ultimately result from bacteria decomposing nitrogen-fuelled algal blooms that have sunk to the ocean floor. As the algae drifts down to the sandy floor below, it is consumed by bacteria and as they multiply they strip the ocean of its oxygen. You may be thinking ‘uh, that doesn’t sound too bad’ but the truth is, these underwater wastelands are actually far worse than we realise.
What’s so bad about a dead zone?
One of the world’s largest dead zones can be found in the Gulf of Mexico where its suffocating grip on marine life encompasses a staggering 22000 km2. To illustrate how big an area that is, the total area of Gauteng is 18178km2. But it’s no City of Gold. Where dead zones occur, most marine life either dies or if they are as the saying goes ‘lucky fish’ they may be able to swim to safety. Habitats that would normally be teeming with life become, essentially, biological deserts.
Industrial Agriculture: one of the largest contributing factors to ocean dead zones
Out of sight out of mind – we often forget that what we do on land always effects the ocean. One of the greatest impacts on dead zones is industrial animal agriculture, for example. To your average gardener, a little bit of manure or fertilizer is a good thing as it forms a part of the nutrient cycle required to keep the grass green. This advantageous view of animal waste, however, falls apart when industrial farming systems are brought into the picture.
How does commercial farming on land effect the life aquatic?
For the majority of animals that have the misfortune of finding themselves on large industrial farms, their food sources are often pumped full of antibiotics and hormones to fast track their growth. These chemicals, through natural bodily functions, leave our furry friends on the farm and end up in our waterways and ocean harming local marine life. In some cases these chemicals, such as oestrogen, are causing certain fish species to change sex. As scary as transgender fish may sound, the real horror story stems from the totally absurd amount of animal excrement that is making its way into the ocean.
The scale on which these large industrial farms produce animal waste creates nitrogen shocks to the environment. Logically, most of us are aware that littering could eventually pollute the ocean, yet we chose to remain ignorant about the threats, such as dead zones, that are strangling our seas. When it rains, a toxic soup of chemicals made from a mix of pesticides, fertilizers and animal waste leaves the farms and enters our water ways as runoff.
What are the consequences?
This polluted stream sets off on its cyclic journey to the ocean where it is unceremoniously dumped. The consequence? Disease outbreaks as well as damaging algal blooms. According to the Food and Agricultural Organization, animal agriculture produces more greenhouse gas emissions than all trains, cars, boats, motor bikes and planes combined. As a principal driver of global warming, animal agriculture and its resultant air pollution is negatively impacting our beloved oceans in two major ways, beyond dead zones.
Increase in global ocean temperatures
Firstly, along with other sources it has brought about an increase in global ocean temperatures resulting in widespread coral bleaching and subsequent mass coral die offs. The majority of us, as the wave fueled junkies we are, have had an experience with a reef or two in our time. Surpassing their ability to help crank out some of the gnarliest waves, these reefs form an integral part of the oceans ecosystem. These rain forests of the sea are biodiversity hotspots, serving as the oceans ‘petrol stations’. Without coral, it would not be possible to support the overwhelming amount of life that exists within this liquid realm.
The second problem, ocean acidification, is so severe in some parts of the ocean that it’s preventing shellfish from developing their namesake – shells. The ocean water is so acidic that it is dissolving these species shells’ faster than they can naturally be created.
The water is our home – keep it alive
The pressures being placed on the ocean by humankind are unprecedented. As if the evil brought about by overfishing is not bad enough, humankind through our own doing are now changing the very fabric of our oceans.
Some of us have been lucky enough to know what it’s like to be in the presence of truly beautiful marine life whilst surfing. Whether it be dolphins carving through a glassy set less than ten metres away, or maybe, it’s as simple as a tiny anonymous fish flopping onto your board while it searches for its school.
Humans might not instinctively associate the ocean with home. But I like to think that surfers are not like most humans. When we surf, we are home. Without the water and the life existing below our boards, we are just not the same. So as representatives of the blue planet we need to educate ourselves and start taking notice of what the majority are dead to, the truth.
About The Author: Sean Kelly is a lifetime surfer and conservationist with an academic background in both Environmental Science and Environmental Management from Rhodes University, South Africa.
*Lead Black&White Image: Namibia © Nikolai Hof / Shotbru
*All Other Images © Greg Ewing