Naked Science Forum

Life Sciences => Marine Science => Topic started by: katieHaylor on 19/04/2018 08:41:59

Title: Are underwater explosions harmful to marine life?
Post by: katieHaylor on 19/04/2018 08:41:59
Donald says:

I know a stick of dynamite will stun and kill a lot of underwater life when it detonates. The superpowers exploded nuclear weapons in the oceans. What was the kill/stun radius and did anybody document it?

What do you think?
Title: Re: Are underwater explosions harmful to marine life?
Post by: chris on 03/06/2018 09:49:32
Anyone know how to go about calculating this? The energy is going to dissipate as a sphere-shaped function in the water, I would think...
Title: Re: Are underwater explosions harmful to marine life?
Post by: alancalverd on 03/06/2018 23:17:29
Not sure about the numbers, but sub-kiloton depth charges were suggested for antisubmarine warfare. The kill radius has to be limited because the surface ship can only depart the drop point at around 40 kt, so you are unlikely to be more than a mile away when the bomb explodes. You could drop a larger charge from an aircraft, but you lose accuracy at 200 kt,so there's an element of "swings and roundabouts".

Nuclear torpedoes have been manufactured with yields of around 10 kt and a target range of about 8 miles, but the greater probability of a hit or proximal detonation means that in fact the kill radius needn't be as large as a depth charge.

As we know from surface bombs, the destructive radius varies with the square root of the energy yield, which is why few bombs have ever been made with more than 10 megaton yield - there's a better chance of destroying most targets with two small rather than one large bomb.

Anyway, you are going to end up with a lot of inedible fish sauce and some very grumpy whales.
Title: Re: Are underwater explosions harmful to marine life?
Post by: Colin2B on 04/06/2018 07:48:27
The underwater nuclear tests were more interested in damage to ships and submarines and Iím not aware of any results for the effects on marine life.
There has been quite a bit of research on effects of underwater charges in naval demolition  training areas where the interest is in the damage to all forms of sea life and in particular the risk to divers.
If I remember correctly the underwater the damage appears to vary with the cube root of yield compared to the square root @alancalverd mentions for air. Although the effect is of an expanding sphere there is a greater effect from relected pressure waves than in air, particularly from surface reflections. Interestingly fish with swim bladders are more likely to be killed than those without.
Title: Re: Are underwater explosions harmful to marine life?
Post by: RjMaan on 24/06/2018 08:40:43
Yes, absolutely. Underwater explosion is very dangerous for the marine life. It can also disturb the marine ecosystem if the explosion is on large scale.