• Question: How much percentage of the underwater wildlife have been affected by pollution?

    Asked by anon-278692 to Alistair on 2 Feb 2021.
    • Photo: Alistair Young

      Alistair Young answered on 2 Feb 2021:

      All the life in the river has been impacted in some way as the pollution changes the environment – for example fertiliser in run-off from a farm will add nitrogen to the water, encouraging algae to grow which chokes off other plant forms and adds shade… so the invertebrates and mini-bugs struggle to survive… and fish and other creatures which feed on the invertebrates also suffer… so on up the food chain

Comments

  • Photo: Alec

    Alec commented on :

    A good question. As Alistair says, wildlife in rivers (and lakes) has probably suffered much more than the marine environment because rivers tend to be nearer to sources of pollution. But the marine environment is also badly affected – although the vast size of the oceans often means chemical pollution is broken down and dispersed to low levels more easily than it is in rivers or lakes. However, as you’ll probably know, plastic pollution is very widespread and is likely to cause problems throughout the food chain as it breaks down into microplastics and is ingested by some of the smallest underwater organisms: zooplankton (often babies or larvae of crustaceans, fish, and cephalopods). It’s even been found at the greatest depths of the ocean – so it seems there are few places that this kind of pollution has not reached.

    Although plastic pollution has got a lot of attention, however, it is still a relatively minor environmental issue compared to climate change, ocean acidification, and global warming. There are also other types of pollution such as chemical pollution from ships, land, and rivers. In particular, chemicals called Polychlorinated biphenyls (PCBs) are worrying scientists as these may reduce the fertility and health of marine mammals (and of their babies).

    There’s also other forms of pollution we don’t think about as much. For example, sound pollution from ships and SONAR used by military warships and submarines. Shipping noise is making it harder for marine mammals to communicate underwater with each other, and may be disrupting whale migrations. SONAR is even more dangerous, as this extremely loud sound pollution has been linked with whale strandings – it is thought that the loud and sudden noise generated by warships using SONAR causes dolphins and whales to panic and rush to the surface if they were at great depths. This can cause ‘the bends’ or decompression sickness in whales and dolphins and often leaves them injured and disorientated. Then unfortunately they often strand or beach themselves on shore.

    So there’s lots of forms of pollution and almost all species will be affected by it. But some much more than others – some will be able to cope, some will not. So it’s up to us to try to limit the pollution we create and help as much underwater wildlife as possible to cope with the pollution we’ve already created.