Sunday, January 24, 2010

Saudi Arabia: Science at Sea

Dr. Randi Rotjan, Saudi Arabia Expedition

For the past 10 days, I (+ 8 colleagues) have been onboard the R/V Dream Island, diving and working everyday around the clock in order to answer questions about fish-coral interactions (and other things) in the Red Sea. To give you a glimpse of the on-boat experience, I'm thrilled to have some video footage to include (shot and narrated by Nancy Berumen). This first short clip shows Michael and I in prep for a dive (hydrating and getting gear together), with a reef in the background (our boat is anchored to the reef). Check out the changes in surface coloration - you can see the reef from the surface:

By day, we were working mostly underwater doing transects, collecting samples, capturing images, recording behavioral observations, etc. By night, we had to work up our samples, enter our data, download our images, and prepare for the next day's dives (3-5 dives per day!). However, space was limited, and we turned our dive benches into lab benches. Using headlamps for light, luggage for seating, and dive gear surrounding us as ambiance, we worked around the clock to make sure that all the work was done properly (again, video by Nancy and Mike Berumen):

So, what's it like underwater? What are we doing, exactly? As I've previously mentioned, there are many different scientific objectives on this boat, and I've already given you all of the details on the Finding Nemo project. As always, I was working on fish-coral interactions, trying to figure out which fish eat corals, why fish eat corals, and what that means for the corals. I'll spare you the gory details, but this basically involves (among other things) having a pretty good handle on coral taxonomy. The Red Sea hosts some unusual corals, so I spent a lot of time studying! Here's a glimpse of some of my favorite Red Sea coral critters:

One of these, (middle row, R) Cynarina lacrymalis, is my new favorite coral. It's only a single polyp and very rare, but it's extremely distinctive and very beautiful. I also love Mycedium umbra (middle row, L), Galaxea (top row, middle) and Astreopora (bottom row, middle with the gratuitous Chromodoris quadricolor nudibranch for fun). I won't bore you with all of the taxonomic details, but it's clear that the Red Sea hosts a high diversity of corals, and it's a challenge to be able to identify them all quickly underwater!

We measure the corals along a transect (see the measuring tape above), and from these coral counts and measurements we get a sense of the benthic cover and coral health (among other things) at a site. But of course, to measure them, we first need to know who they are.

Gerrit and Mae topside, identifying corals

In addition to coral identification, we often need to measure something more closely - see this coral above? It has some scars on it (likely made by a fish that was eating the coral), and some dead patches. Using a ruler, we can estimate the amount of living tissue. And, though we're pretty good with our coral identifications, sometimes we have to use photographs to help us - immediately after a dive, we compare our notes and photographs with taxonomic guides to confirm what we've seen.

We also need to keep our samples organized. Underwater, things are collected and carefully recorded onto underwater paper. Then immediately on boat (often still in a wetsuit!), samples are placed into tubes, labeled, categorized, and properly stored. Without constant vigilance, samples would get lost, disorganized, mislabeled... and all of that work underwater would be lost. Data are also immediately transcribed onto a computer and data sheets stored for reference.

Finally, naturalists at heart, we try to identify things outside of our research areas that are new to us. For example, I saw a lot of new (to me) bivalves on this trip. The first time I saw Pedum spondyloideum (the coral scallop - below left), I immediately checked our references to determine its identity. Needless to say, we had a staring contest - but I blinked first. See all of the eyes? They are red, and line the mantle. These scallops are extremely interesting - they are embedded within corals and are thought to feed on plankton. Similarly, I had never seen Spondylus mafrisrubri before (the Red Sea thorny oyster, which is actually another scallop, below right), so it was great fun to add these creatures (and more!) to my repertoire.

Being a naturalist is an important part of being a field biologist. Knowing how to identify species, where they are commonly found, and who they are related to is essential to really knowing an ecosystem. After all, without taxonomic knowledge, it's hard to get perspective on ecology. Many of you are probably naturalists as well - many hobbies are born of naturalist tendencies (birding, gardening, fishing, etc). Still, coral reef ecosystems are among the most complex and diverse on earth - so it's not always simple (but don't get discouraged).

So, for me, science at sea is a mix of taxonomic identification, ecological categorization, collecting samples and behavioral observations. Above all, organization is the key to a successful trip. My time at sea is basically at an end for now (more on that next post), so I'll take my 10 days worth of data, samples, and impressions and will begin the terrestrial task of trying to understand all that I've seen. It will take several months to unravel all of these observations, but in the end, we will (hopefully) have answered some of our questions, discovered new ones along the way, and have a better understanding of coral reefs in the Red Sea. As for science at sea, it's been fantastic. But now, land ho! It's time to head to shore.


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