Estate Living Magazine #liveyourbestlife - Issue 46 December 2019 | Page 41

C O M M U N I T Y
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.
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
L I V I N G
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?
Phytoplankton
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.
However, pollution also consists of pathogens, and here it becomes
really scary. We are seeing, for example, an increase in cases of
Forget the sharks – beware the flesh-eating lurgies
W
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.
Pollution