Oceans in Crisis - Ocean Worlds: The Story of Seas on Earth and Other Planets - page 170

and ichthyosaurs and plesiosaurs before them. But in each case the
transition to the sea was slow, via a progression of species that became
successively better at paddling close to shore, to briefly swimming out
a safe distance, to eventually cutting ties with land altogether. And in
each case the final step did not mean attaining an easy and utter
dominance. It simply meant sharing that ecospace, more or less
successfully, both with earlier marine pioneers and with the lineages
that had stayed true to the sea throughout—the sharks and large
predatory fish.
In the Jurassic, for instance, the ichthyosaurs and plesiosaurs (many
species of both) shared the position of top predator with the sharks
and with fish such as the enormous Leedsichthys , over 15 metres long.
There is usually some kind of coexistence here, if an uneasy one,
among neighbouring tyrants. We humans have broken that power
structure of contemporary marine predators. What is left is the small
fry—that we are, too, harvesting as we fish down the food chain. For
the oceans, it has been a unique form of reshaping—and one whose
effects can only be compounded as we reshape the physical and
chemical structure of the ocean. That process, as we shall see, has only
just begun, and is so far mostly invisible to the casual glance—in
temperate climes at least. But there's no way to avoid litter.
Litter
In 1997, Charles Moore sailed from Hawaii to Long Beach, California.
It is a beautiful, calm stretch of ocean. The voyage took him a week—a
week that should have been idyllic. His idyll was spoilt, though, by
litter. There was not an hour in that week-long voyage when he did
not see, bobbing in the sea, a bottle or a piece of plastic. Just how
much litter was there in that stretch of sea, he wondered?
Moore returned, having persuaded some marine scientists to go
with him. This time they trailed behind them a net that was designed