Answer:
COWS: fertilizer runoff
phytoplankton: acid rain
fish eggs: fertilizer runoff
Step-by-step explanation:
Cows produce manure, this manure has a chemical called Stercobilin, when/if this chemical is separated from the feces, it can cause mass pollution, as it has been found that this chemical is what pollutes most of the rivers (as of 1932)
Phyto-plankton are responsible for most of the transfer of carbon dioxide from the atmosphere to the ocean. Carbon dioxide in the air can dissolve in rain water to form carbonic acid (H2CO3). Carbonic acid is a weak acid. It partially ionizes to form hydrogen ions. The hydrogen ions from carbonic acid giving natural rain water a slightly acid pH value of about 5.6
Although it seems unlikely, fish subsistence and farming causes a lot of pollution that is spread into the ocean and dispersed.
I hope this helped, sorry if any of my reasonings are wrong, I'm speaking from my prior knowledge to the aspect of pollution and my research on it in the past.