Ask an Explorer

Questions were sent to the science party during this expedition. Selected questions and answers are offered below.

Question from: The Slatterys

What is in the Trimix that you dive with?

Answer from: Marc Slattery, Chief Scientist/Principal Investigator, Cayman Islands Twilight Zone 2007

Trimix contains three gases: oxygen, nitrogen, and helium. The first two gases are part of the normal air we all breathe, and scuba divers breathe the same air under pressure. Unfortunately, oxygen and nitrogen can cause various medical problems when breathed at depth, including narcotic effects and, potentially, toxicity. So to lower the concentration of these gases, deep divers add helium, an inert gas. The result is a mixture that is safe to breathe as deep as 300 feet, which is where we will be working.

Question from: The students at Mountain Brook High School

Have the explorers done any dives yet? If so, what have they found?

Answer from: Marc Slattery, Chief Scientist, Twilight Zone 2007

Two members of Team Twilight Zone started diving about four days ago; they've completed 12 dives on the shallow reefs near our study site. These surveys will help us identify the connectivity between deep and shallow communities. For more information on this, see our first Web log!

Question from: Kim

What is "pharmacognosy," the term that is mentioned (elsewhere) on the Ocean Explorer Web site? I can't find the word anywhere.

Answer from: Marc Slattery, Chief Scientist

Pharmacognosy literally translates as "drug knowledge." The study of pharmacognosy is the study of natural products for drug discovery. One of the biotechnology goals of this project is to evaluate the organisms we collect from the Twilight Zone for biomedical activity. This work is conducted at our home campuses — the University of Mississippi, University of New Hampshire, and University of Alabama — and at the National Center for Natural Products Research. These marine natural products might one day become an important cure for cancer, malaria, or an infectious microbial disease.

Question from: Christy, West Virginia

What are the biggest obstacles to preserving these deep-reef habitats? Would they be damaged by proposed plans to sink carbon dioxide into deep-ocean troughs in an effort to slow global warming?

Answer from: Marc Slattery, Chief Scientist

Currently, the most obvious impact to deep reefs is commercial trawl fishing and/or anchoring, which can destroy the habitat. I personally feel that the lack of information on deep-reef communities is a danger since many of the reefs are not even mapped, thus they can't be managed and preserved. Clearly, further research will highlight the species present, and their potential responses to future environmental change. Carbon dioxide infusion has the potential to cause ocean acidification, which has been shown to be problematic for those species that lay down calcium carbonate (e.g., corals, gorgonians, and mollusks — all important members of deep reef communities).

Question from: Alex, Oxford, Mississippi

Your images of the different sponges look just like corals. What's the difference between a sponge and a coral?

Answer from: March Slattery, Chief Scientist

Both are way cool groups of invertebrates (animals without backbones)!!! But sponges and corals are very different groups of marine invertebrates. Sponges are an older group that are based on cellular organization, while corals are based on a tissue-level organization. Both can harbor symbiotic algae, but corals have turned this symbiosis into an art form that results in dramatic energetic resources for calcium-carbonate deposition and, subsequently, the stony coral reefs of the tropical nearshore marine environments. However, we are learning more each day about the importance of the associated sponge communities.

Question from: Richard

Is identifying a sponge difficult? Do things like different growth forms help or hinder an identification? How many different types are there?

Answer from: Beth Hines, Educator-at-Sea, with Deborah Gochfeld, Senior Scientist, and Cristina Diaz, Research Associate

Hey, Rick — thanks for the question! From my observations, identifying sponges is fairly difficult. They have to be sectioned and looked at under a microscope to identify what type spicules they have, if any, and in what arrangement. Researchers also look to see whether the spicules are arranged in a "skeleton proper" arrangement, or if the sponge has incorporated sand grains or other items (like foreign spicules).

Different growth forms do, indeed, make a sponge difficult to identify in the ocean. The divers on this team are working at many different depths, and sponges that grow small on the shallow reef grow much larger on the wall in the Twilight Zone . . . much, much larger in some cases. One elephant ear sponge was seen at a deep depth that was as big as the boat we were on!

Our resident sponge expert, Cristina Diaz, says that more than 5,000 sponges have been described, but she and other sponge taxonomists agree that there are, at the very least, around 10,000 species out there. This leaves a huge number of sponges yet to be discovered and studied.

Question from: Merritt, Mountain Brook High School

Will the divers bring samples up from the depths of the Twilight Zone? If so, what kind of organisms will be collected? What kinds of experiments will the team do to analyze their samples?

Answer from: Beth Hines, Educator-at-Sea

Great question, Merritt (marine-scientist-in-training)! The divers have already brought up more than 100 sponge samples and several coral samples. Some samples have been from the deeper depths, and they often look much different from the ones found at shallow depths. They can be much larger, or a different color, or release more mucus. or even smell different. (Not necessarily good, just different!)

The scientists are keeping a voucher sample to verify taxonomy, a tiny sample for molecular analysis to be included in the Census of Marine Life (global database of marine life), and an archived sample for future molecular work. The main part of the sample will be used to measure for possible pharmaceutical activity.

In order to bring samples back to the United States, the scientists have to fill out lots of forms and permits and follow the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) guidelines. Even so, they are almost always stopped in Customs and questioned about the weird things they are carrying with them.

Question from: Sarah

This exploration looks cool! I read in the Mission Plan that some shallow-water fish and coral are taking refuge in deep reefs due to, I suppose, some environmental factors. Are y'all looking to investigate the environmental factors or to check on the adaptability of the shallow reef fish and coral? Also, if they're adapting, should we worry about the environmental factors, or are we watching evolution in progress?

Answer from: Beth Hines, Educator-at-Sea; Marc Slattery, Chief Scientist

Awesome questions! According to the researchers, the connectivity of reef systems is the focus. Some corals grow in shallows only, some in deep only, some in both. The question is: Do the deep corals "seed" the shallow corals, or are the shallow corals releasing propagules ("seeds") to the deep corals? And, certainly, some environmental factors will have an influence, as will other factors (such as the amount of food available). You have gotten to the heart of the research.

Question from: Mare

As you stated on your Web site, the Cayman Islands sponges appear to be healthy, but I'm wondering if you noticed a decline or increase in species diversity among the sponges or other organisms during your current project.

Answer from: Beth Hines, Educator-at-Sea; Marc Slattery, Chief Scientist

This is the first year that this team has studied this site, and they are finding amazing diversity among sponges and corals here. It is certainly among the most diverse sites within the Caribbean. Next year, when the team returns to this site, they will be exploring the very question you posed: Has the diversity of sponges and corals increased, decreased, or remained the same? This data will provide information about whether these sites are pristine, or whether they are impacted by human and/or environmental factors. This information will be transferred to local environmental management teams for ecosystem monitoring.

Question from: Lexi, Lacordaire Academy, New Jersey

What kinds of corals grow near the Cayman Islands? How do shallow-water and deep-water corals differ, aside from the fact that deep water corals have adapted to the lack of light?

Answer from: Beth Hines, Educator-at Sea; Marc Slattery, Principal Investigator; Michael Lesser, Research Professor

Thanks for the terrific questions. First of all, there are about 80 species of corals in the Caribbean, compared to at least 10 times that many in the Pacific. Of course, the Pacific Ocean is much closer to the center of coral biodiversity, which includes Indonesia, Papua New Guinea, and the Philippines.

Deep corals are found in less abundance and distribution than shallow corals. Deep corals differ from shallow corals in morphology (body shape) and sometimes in color. Some corals have a symbiotic algae living within their cells. The algae photosynthesizes to make food for the coral, and the coral provides raw materials for photosynthesis, as well as protection. Deep-water photosynthetic corals have less sunlight to photosynthesize so they increase their surface area by growing bigger and broader in order to capture more sunlight. The algae, called zooxanthellae, have more cholorphyll in deep-water corals, which is also an effort to catch more sunlight. This makes the coral look more brown (not green!) because zooxanthellae have several other pigments in addition to chlorophyll.

Question from: Linda

I was wondering how much algae coverage you see on and around the corals at these sites? Does the algae coverage vary with depth?

Answer from: Beth Hines, Educator-at Sea; Michael Lesser, Research Professor

Qualitatively, down to 100 feet (ft), there is about as much algae coverage as is found in shallower depths above 100 ft. But because there is less coral cover, there is proportionally more algal cover. The algae are growing fine at 200 ft under very low light conditions. The predominant species is Lobophora sp.

Question from: Andy (age 6) and Annabel (age 8), Birmingham, Alabama

These pictures and sounds and videos are really cool. We love the ocean and the plants and animals that live in it and we want to learn more. How old do you have to be to do this type of research and how old do you have to be to do scuba diving? Is it difficult for the human body to do scuba diving? Thanks a lot and keep up the great work guys!

Answer from: Beth Hines, Educator-at Sea

Andy and Annabel — We are so glad that you have enjoyed following the expedition. Diving and seeing the plants and animals has been an awesome experience. Children can scuba dive with their parents when they are about 8 to 10 years old and can be certified to dive at around 10 to 12 years old. Scuba divers have to follow lots of rules in order to dive safely and stay healthy. It is a safe sport if the rules are followed.

To be a marine researcher, you will have to go to school for a long time. These investigators all have PhDs in science. After they graduated from high school, they went to college for many years. Today, they study the plants and animals in the ocean and learn how they interact with the environment. Careers in science are very exciting . . . but scientists do work very hard.

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