In which DCist interviews area scientists, researchers, and academics on topics pertaining to natural and scientific interests. As Thomas Dolby would say: science!

Carole Baldwin, a Smithsonian Institute research zoologist, is the curator of fishes at the National Museum of National History's newly opened Sant Ocean Hall. Baldwin spent 14 weeks in 1998–99 filming a 3-D IMAX documentary on marine life at the Galapagos Islands. A systematic ichthyologist, Dr. Baldwin has discovered new species in Belize, Tobago, Cook Islands, Australia, El Salvador and the Galapagos Islands. Much of her research centers on deep-sea fish and its genealogical relationship with coral reef.

DCist: An exhibit in the Sant Ocean Hall mentions a mass extinction event near the end of the Permian era that killed 95 percent of ocean life. How did the 5% survive? Does all ocean life today descend from those five-percenters?
 
Carole Baldwin: Global mass extinction events don’t wipe the slate clean. In other words, not everything dies: there are “winners” and “losers.” Paleobiologists do know that some of the species that survived the Permian extinction were widespread, suggesting that they had adapted to varied conditions. That adaptability may have helped them survive the upheaval. Survivors of mass extinctions are all that’s left to give rise to new species, so, yes, all ocean life today descended from that 5% that survived the Permian extinction!

DCist: Throughout parts of the exhibit are jars packed with krill. What percent of the ocean's biomass does krill account for? The ocean is chock full of this stuff.

CB: I’ve never seen a figure that estimates the percent biomass that krill accounts for worldwide. However, to give you an idea of how large it can be regionally, in one study of krill biomass in the Southern Ocean, krill (along with their eggs and larvae) constituted over 60% of the average total zooplankton biomass. They can occur in huge swarms, hundreds to thousands of meters long with ten thousand or more individuals per cubic meter of water.

DCist: Krill even migrate from deeper water to shallower water throughout the day so that more kinds of species have an opportunity to eat them.

CB: Regarding vertical migration of krill, one study suggests that the reason for their going up and down is a bit different from the usual—the “usual” involving organisms that live in midwater depths (200-1000 m) migrating upwards at night to feed in the more food-rich surface zone and then moving back down at dawn. Krill feed on phytoplankton, which only lives in the surface zone, but with a gut full of food, they sink! While digesting food that’s in the gut, they make their way back to the surface to feed again. They may do this several times a day.

DCist: Could today's ocean survive if something were to threaten or kill off krill?

CB: Nobody knows, but history –e.g., mass extinctions – suggests that other species would evolve to fill the krill’s niche. It’s worth noting that krill are being threatened. Krill’s furcilia larval stage eats algae on the under side of sea ice. Declining sea ice and global temperature change may harm krill populations, which could have an impact on many polar animals. Krill are also commercially fished, but the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has established maximum catch quotas.

DCist: Does the ocean's total biomass change with global warming? Is it possible to tell how today's biomass rates with the ocean's biomass at points in the distant past?

CB: It would be hard to isolate the impacts of global warming on ocean biomass because there are so many other factors affecting biomass (e.g., over fishing, pollution, habitat degradation). I don’t know the answer to the second part of the question (I have sent it to a paleobiologist on our staff), but clearly the biomass today would greatly exceed that following, let’s say, one of the mass extinction events.

DCist: The Dunkleosteus terrelli has no teeth but rather parts of his skull, like his jaw, that appear to be sharp. Did teeth evolve in the ocean?

CB: Yes. Although some organisms that lack jaws have tooth-like structures, what we consider to be true teeth evolved in association with the evolution of true jaws. The armored fishes, such as Dunkleosteus, didn’t have true jaws. The first vertebrates with true jaws were cartilaginous (e.g., sharks) and bony fishes.

DCist: What is the rarest living creature on display at Sant?

CB: We only have one display of living organisms in the exhibit – the Indo-Pacific coral-reef tank. In that tank, the rarest living creature is the mandarin fish. Not that mandarin fishes themselves are rare (although they are over fished because of the commercial aquarium industry); the reason that our mandarin fish are rare is that they are the first captive-bred mandarin fish on display in the world. A graduate student at the Florida Institute of Technology, Matthew Wittenrich, developed the technology to breed mandarin fish in captivity, and he provided several of his specimens for our exhibit. To get them here, he had to put the bags containing the seawater and fish in his checked luggage: airport security (the “no liquids” rule) would not allow him to hand-carry the fish on the plane!

All of the other specimens on exhibit are preserved specimens, some dry (e.g., sea stars, corals, fossils) and some wet (e.g., fishes, some crabs, worms, sea cucumbers). The “wet” specimens are typically kept in alcohol in the Smithsonian’s archival collections, but fire-code regulations wouldn’t allow more than 10 gallons of alcohol in the exhibit. The liquid the specimens are in for this exhibit is called Novec, and it’s produced by the 3M corporation. This fluid has not been tested as a preservative for specimens over long periods of time (the exhibit will be up 25-30 years), so the entire exhibit is something of an experiment!

There are numerous rare preserved specimens on exhibit, including a coelacanth (a “living fossil” fish), a red sea star from the deep ocean (Narcissia ahearnae), a small anglerfish (Linophryne arborifera), hydrothermal-vent animals, and dozens of fossil specimens.

DCist: Three scientists just won the Nobel Prize in chemistry for isolating the green fluorescent protein in crystal jellyfish. What sort of applications can research on this fluorescent protein contribute to?

CB: For molecular biologists, the ability to track the fate of individual cells by observing a glowing protein within them has huge implications. Particularly in the medical field. Some examples (as listed by the Nobel Prize jury and other sources) include tracking the fate of nerve cells damaged in Alzheimer’s patients, observing how organs function, tracking the spread of disease, and analyzing the response of infected cells to treatment.