When you live near the coast in the open water and ...

at the same time the phytoplankton are decomposing, you have two choices you stay and die due to suffocation or you flee to somewhere with higher oxygen levels. That's the situation the animals and plants are facing on the bottom of the ocean floor when the high winds drives the water to the shores to create tides, which causes upwelling.The problem is that some slow/stationary animals like sea cucumbers, crabs, and sponges cannot escape this harmful event, so they end up dying in the end leaving a depressing zone of dead animals that couldn't do anything about this sticky situation.

While this may be natural, these low-oxygen(hypoxia) zones are increasing in size. Some scientists say this may be related to global warming as the three main oceans are absorbing the CO2 and other greenhouse emissions. This may upset the ecosystem and cause some of the species of crustaceans and fishes to decline in population. We're hoping this doesn't spread to the open ocean, where sharks, dolphins, and whales are living in along with the other marine creatures.