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Summer is around the corner, and you’re probably thinking about heading to your favourite coastal holiday spot. It’s a great opportunity to gaze out to sea and contemplate – nothing! But, perhaps it’s also a good time to think about the sea. We can’t imagine a world without it, and it is so big, we can’t imagine it ever changing, or being vulnerable. But it is. And it is time to think about it.
Floating in the lifeless infinity of outer space is one single planet that’s blue in colour. That tiny planet is called Earth – but we call it home. Think of it in the same way you think of your house or apartment, the estate on which you live, and the city and country in which they are situated. Because, like those little comfort zones, Earth is finite and precious. And vulnerable.
The earth is blue because it consists mostly of water, and it is the only place in the known universe where water exists in solid, liquid and vapour forms. And it is this water that makes life as we know it possible. We humans and many other life forms, including plants, are totally dependent on fresh water for our survival, but less than 2% of all water on Earth is fresh – and most of it is tied up in permanent ice at the polar regions and on high mountains.
Size does count, but …
You have often heard it said that the extensive terrestrial forests are the lungs of the Earth, which is true. In a sense. Forests are important, as are the giant trees within them, but they pale into insignificance in comparison with the sea for oxygen generation and carbon sequestration. You see, most of the oxygen we breathe comes from the top ten metres of the ocean where gazillions of teensy weensy plants, a.k.a. phytoplankton, live. So, while we are – rightly – alarmed by fires in the Amazon, we ought to be incensed, outraged and terrified by the destruction of our ocean ecosystems, for we are more dependent on them than even the greatest forest on Earth.
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Understanding ocean water quality
The water on our planet has existed since its birth out of a chaotic fireball of molten rock and gas. There is no more or less water on Earth today than there was when the dinosaurs roamed free, or even long before that – before the continents were formed from the breakup of Gondwanaland. All water on the entire planet is connected in a single hydrological cycle. No new water is created, and no old water is destroyed, for water is a flux that moves perpetually in time and space. It merely changes form from saline to fresh, and back to saline, in a rhythm as old at the solar system. The volume remains unchanged, but the quality fluctuates wildly.
Ocean water contains many dissolved minerals, including – obviously – salt, but another crucial mineral is calcium carbonate, which is the fundamental building block of all biological life. It forms the bones of land animals and the shells of sea creatures, and, because it is alkaline, its presence defines the chemistry of the ocean. So, while fresh water is mildly acidic, the ocean is mildly alkaline, which is why acidification of the oceans is such an important issue. Even a slight change in the alkalinity of the sea means that corals die, sea creatures can’t form shells, and all life forms armoured with these protective elements can no longer survive. Acidification is caused by elevated levels of carbon dioxide and sulphur dioxide, both of which are produced by burning fossil fuels, and form part of the process of acid rain.
Are we running out of water?
Our need for fresh water has outstripped supply at the global level. But this doesn’t mean we’ve run out of water, just that we have run to the finite limits of fresh water that is not trapped in glaciers and icecaps.
This is because of population growth and demand for food and employment. Some countries are more acutely affected than others, but globally we are in trouble. This is a problem for some very obvious, and some not-so-obvious reasons. Obviously, actually running out of fresh water in any one place is a disaster – ask any resident of Cape Town or Makhanda (formerly Grahamstown). But, even if we still have enough water to use, less water means a loss of dilution. Stated simply, everything we ever put into any sewer on land eventually ends up in a river where it gets diluted. Reduced dilution capacity means that more pollution is passed onto the oceans, for all rivers eventually flow into the sea.
Pollution
Pollution is complex. Rivers accumulate stuff, so everything ever dumped into them eventually makes its way into the top ten metres of the ocean, where oxygen is generated, and where carbon is removed. Pollution contains many things, including nutrients, mostly from sewerage and agricultural run-off. One would think nutrients are a good thing, but too much nutrient can cause toxic red tides, which are increasing in frequency and size, and also –frighteningly – extending their range into places that have never experienced them before.
Forget the sharks – beware the flesh-eating lurgies
However, pollution also consists of pathogens, and here it becomes really scary. We are seeing, for example, an increase in cases of flesh-eating bacteria (Vibrio vulnificus), which is often associated with the presence of sewerage outfall. In Durban in 2014, Dr Peter Breedt of Hillcrest became infected while paddling in the ocean. Intense medical intervention saved his life, but it was touch and go. Not so lucky was eight-year-old Liam Flannagan, who lost his life in 2018 to this pathogen. And it’s not just in the oceans. In 2017, Johannes Smit from Vanderbijlpark was infected while fishing in the Vaal River, and in 2019 Madeleine Carelse, also from Vanderbijlpark, ended up fighting for her life. This risk is becoming more prevalent, because of increased pollution in the oceans, but also because of increasing seawater temperatures creating ideal conditions for rapid growth.
Demon plastic
Plastic is so useful, but we are learning that it is a double-edged sword. Our rivers are choked with the stuff. The Emfuleni crisis was caused by plastic blocking thousands of kilometres of sewer, creating an impenetrable plug that caught everything flowing through it, eventually bursting to the surface as a constant flow of raw sewerage into the nearest river – the Vaal. We are disgusted by these images – and rightly so – but this is not the real issue underpinning plastics. All rivers end up in the ocean, and so, too, does plastic.
Remember the top ten metres of the ocean is inhabited by phytoplankton that synthesise energy from the sun. Just below that layer is a second, slightly darker, one where plants cannot live – but animals can. Trillions of teeny little beasties collectively known as zooplankton populate this darker zone, quietly munching on the phytoplankton. And this is where plastic changes the game at planetary level.
All plastic eventually breaks up into tiny particles known as microplastics. The little zooplankton animals ingest the microplastics along with the phytoplankton, which changes the density of their faecal pellets. Now that may not seem important, but this constant shower of tiny faecal pellets from the zooplankton transfers energy from the sun into the darkest depths of the oceans, in trenches that are deeper than Mount Everest is high. But, because the microplastics change the density of these faecal pellets, they float rather than sink. This single fact alters the transfer of energy at a planetary scale. This is just one of the many reasons why plastics are bad for human survival on Earth.
So, what can each of us do about this?
Understand the interconnectedness of sea and land through the flow of fresh water from rivers. Remember, anything that is improperly discarded – even in Gauteng – will end up in the sea. Eventually.
On a personal level, deal with plastics by demanding of your retail supply chain a change in packaging. Don’t buy personal care products with microbeads, and apply the five Rs to plastic – preferably refusing it and reducing your use of it, or at least reusing and/or repurposing it and, as a last resort, recycling it.
Very importantly, never discard unused medication down the toilet, as this cannot be removed by the wastewater treatment plants and leads to the evolution of drug-resistant pathogens.
At an estate or developer level, plan to, at the very least, enable residents to lighten their impact on our rivers and oceans. Even better, design and manage estates to encourage responsible use of resources, and demand responsible and sustainable practices from all service providers. Create a culture in which residents are aware of how much their actions impact on the environment – even thousands of kilometres from the front gate.
Not all doom and gloom
Don’t cancel your end-of-year holiday on the coast, but be aware of pathogens such as Vibrio vulnificus – they are much scarier than sharks. Keep children away from stagnant fresh water on the upper portions of the beach in the same way you would discourage them from swimming in strong currents; treat any infection with disinfectant early, and seek medical advice if the infection persists.
But enjoy the sea, for it is a manifestation of the only blue planet in the entire known universe. That’s a very big place indeed, so we are truly special.
