Marine pollution; out of sight, out of mind

This blog is the first of two regarding the state of marine biodiversity.  In short, it is in a bad state due to overfishing, habitat destruction and degradation and climate change (which is likely to have an increasingly destructive impact).  In my first blog I will explore the ‘ultimate drivers’, the very root of the problem, of marine biodiversity loss and consider how these ultimate drivers differ from those affecting terrestrial (land) species.

It will be important to bear in mind 4 facts: 1) humans do not live in the ocean, 2) the ocean is very big and humans struggle to conceive of its full size, 3) a pollutant may have an effect a long way away from where the pollutant was released and 4) damage to the seas can be hard to see.  That humans do not live in the ocean has spared it of the habitat destruction which has occurred on land to make way for human settlements (with the exception of land reclaimation).  It also means that humans are less likely to notice damage to the marine environment and, as will be considered in my next blog, means that much of the oceans is not owned (unlike land).

For the rest of this blog I will consider pollution.  The problem with marine pollution is that it is so very easy to underestimate.  For one thing the sea is so huge it is easy for us to write it off as near-infinite with a near infinite ability to absorb and dilute whatever waste we discharge into it.  For example, according to a literature review of the dumping of munitions in marine environments, on 8 separate occasions, between 1945 and 1948, over 4,000 tonnes of munitions were dumped into the ocean http://www.mod.uk/NR/rdonlyres/77CEDBCA-813A-4A6C-8E59-16B9E260E27A/0/ic_munitions_seabed_rep.pdf, page 79.  As the report states, these munitions have significant harmful effects on marine species.

Whilst humans may once have been able to discharge sewage and fertiliser into the marine environment when human densities were low, this can no longer be done without consequence.  When biological waste (sewage or the run off from fertilisers) is discharged in high concentrations then it acts as a fertiliser for algae resulting in algal blooms.  The algae die, are decomposed by bacteria which use all of the oxygen leaving no oxygen for the other species.  The result is a DEAD ZONE.  Our oceans have dead zones because of our actions.

In mentioning agricultural run off I have hinted at another part of the problem.  Fertiliser which runs of a field into a river can have an effect tens or hundreds of miles away.  This distancing of cause and effect means that individuals do not appreciate the effects of their actions and are therefore not in a position to reduce the ecological damage of their actions.  This is where science comes in, to provide evidence that A causes B, to educate the person responsible for A in the hope they will change their actions.  Let me take another example from the Marine Conservation Society website, Chinese lanterns (http://www.mcsuk.org/what_we_do/Clean+seas+and+beaches/campaigns+and+policy/Don't+let+go+-+balloons+and+sky+lanterns).  Chinese lanterns are fire and forget joy, you light them, admire them as they rise and then forget about them as they are carried by the wind.  Yet, that you have forgotten about them does not mean that they have magically disappeared from the world.  A few months back I heard on the radio that the coast guards had asked members of the public to alert them if they were going to release lanterns as members of the public had been mistaking them for flares and alerting the coastguard.  More recently I stumbled across an article explaining the damage they can cause to marine wildlife when they fall to rest on the ocean as litter.  Animals, turtles especially, mistake them for food, eat them and die when the balloons block their digestive systems causing them to starve.

That concludes this blog, let me repeat my main point once more, pollution which affects the oceans can originate many miles away and have effects which humans do not notice.  It is the role of scientists to establish the sources of pollutants which cause harm in the marine environment so that polluters are no longer ignorant and are accountable.  From here, the damage we cause to the oceans can be reduced.  In my next blog I will consider the economics of overfishing.