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I THOUGHT I’d dip into the animal file today and I discovered some interesting articles on life in the ocean. We know a lot about land-based creatures (although we can still find new species in New York City) and we know a lot about the animals that live at the ocean’s surface. We’re also beginning to discover amazing things about the life at the bottom of the world’s oceans. But what about the microscopic stuff and the life that lives in the rest of the ocean between the top and the bottom? We’re just beginning to delve into those regions.

Researchers at the University of British Columbia have recently found a link between inconspicuous “little brown balls,” the algae responsible for toxic red tides and one of the world’s biggest human killers.

The "brown balls" are microscopic algae called Chromera. The ocean is full of little brown and green balls that are often overlooked in favor of more glamorous organisms, but Chromera has proved more interesting than its flashier cousins.

Chromera lives inside corals where it photosynthesizes and provides oxygen for the coral, but it turns out that Chromera has some very unpleasant close relatives like the dinoflagellates – responsible for the "red tide" that kills so many fish worldwide. The other close relatives are things called apicomplexan parasites. Never heard of apicomplexan parasites? Probably not, but I bet you’ve heard of malaria. The researchers suspect Chromera may be a "missing link" between the two.

These microscopic organisms have a huge impact on humanity in very different ways. The same tool set used by dinoflagellates and Chromera to establish symbiosis with corals became an infection mechanism for apicomplexans like malaria to infect healthy human cells. Resolving their evolutionary origins not only settles a long-standing scientific debate but could ultimately provide crucial information for tackling diseases and environmental concerns.

And now for a little insight into the rest of the ocean (besides the top and bottom parts!).

If you're a snack-sized squid or octopus living in the ocean zone where the last bit of daylight gives way, having some control over your reflection is a matter of life and death. Most predators cruising 2,000 to 3,000 feet below the surface spot the silhouette of their prey against the light background above them, but others use searchlights mounted on their heads. Being transparent and a little bit reflective is a good defense against the silhouette-spotters, but it’s deadly against the “headlight fish.”

Transparency is the default state of both Japetella heathi, a bulbous, short-armed, 3-inch octopus, and Onychoteuthis banksii, a 5-inch squid found at these depths. Viewed from below against the light background, these animals are as invisible as they can be. Their eyes and guts, which are impossible to make clear, are instead reflective.

But when they’re hit with the blue light from a headlight fish, they turn on skin pigments, called chromatophores, and become red in the blink of an eye. When the light’s removed, they immediately revert to transparent. Researchers from Duke University used bright LED lights to observe this phenomenon.

Next, the researchers want to investigate the link between transparency and habitat depth for the octopus. Smaller young animals are found higher in the water column and have fewer chromatophores, so they are more reliant on transparency – which makes sense because there won't be predators using searchlights there. But the mature adults have a higher density of chromatophores making them potentially more opaque and they are found in deeper waters (below 2,500 feet) where bioluminescence becomes the dominant light source.

There’s an incredible amount to learn about our oceans. Cruise on over to The Deep website to learn more about it and many other topics. Enjoy!