There is a 5,000-mile-wide mass of brown seaweed known as sargassum, that floats in large masses moving through the Caribbean and will wash up on Florida beaches and reach other parts of the Gulf on its way towards Mexico. Is that a natural occurrence or the result of an environmental imbalance?

It is the latter. It is not natural but rather a consequence of an imbalance of life forms in the ocean overall. This makes this plant species proliferate too greatly and reach an extreme mass that can be deleterious to other ocean life forms. It is an out-of-control growth akin to seeing invasive terrestrial species like kudzu that can take over and choke out other healthy plants of all kinds and gravely alter an ecosystem for the worse. This is a direct consequence of the extraterrestrial manipulation of the environment for the worse. Anything like this, that might not be a primary intention but a secondary downside of their manipulations, they see as a kind of bonus to gain an additional benefit from altering something for the worse, and in large masses this can become more than an eyesore and a nuisance but a liability for wildlife and human safety and well-being.