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The 2011 Philippine Biodiversity Expedition 

May 27, 2011

Like…totally tubular!

Most of the critters I’m working with during this expedition are so tiny that you need a microscope to examine them…sometimes even just to locate them!   There are lots of exceptions, however, and one of them involves a very cool critter called a chaetopterid worm that I encountered the other day. Since it was fairly big and impressive (colleagues actually stopped by to gawk at it in awe) and because these are such creepy-cool worms, I thought I’d share.
seagrass-basura
While working in a sandy seagrass area the other day, I dug up a large parchment (which is sand stuck together with mucus) tube about an inch in diameter that was sticking up out of the sandy sea bottom.
tube
Typically this type of tube houses a fanworm (a sabellid) with delicate fan-shaped radioles stretched into a sort of funnel-shaped plume like this:
sabellastarte
In sabellid fanworms each radiole has tiny hair-like structures called cirri used to filter small particles of food from the water to be carried to the mouth.   So considering the tube’s appearance, I was expecting a nice fat fanworm to emerge as I eagerly cut into my tube back at the lab, kind of like I was unwrapping some sort of creepy worm shaped gift.  This tube, however, was shaped more like a “U” buried under the sand and so I suspected that it might house something a bit different. And it did…a very large chaetopterid worm!
chaetopterid-whole-body
Chaetopterids are very specialized polychaetes (marine bristleworms) that live their lives confined in tubes. These worms have 3 distinct body regions: the head/anterior region is large and equipped with bristles and a set of palps used for sensory.  The middle of the body is made up of the darkened gut and highly modified lobes that pump back and forth like big flaps to provide a steady water current used in feeding.
ant-chaetop2
The tail/posterior region is more “normal-worm-looking”, meaning long with foot appendages called parapodia carrying bristles on either side of the body.

http://youtu.be/1rIZaPXP9YM

These worms feed using mucus nets which they string across the inside of their tubes to trap food particles by pumping water through their tubes to filter food onto the net.   Once it’s full of food they eat the whole deal and then proceed to make a new net. Other critters, such as smaller worms and crabs, often live alongside chaetopterids in their tubes as commensal animals which score free food scraps and shelter while living there.

Another cool thing about these worms is that even though they live rather clandestine lives hidden in tubes, they produce bioluminescence (they emit light!). What in the world they are doing with this light-producing capability?  Well, we don’t know for certain.  Studies have shown that when a chaetopterid is disturbed, it shoots a wave of glowing particles from its tube.  One idea is that this light surge alerts prospective predators that “I don’t taste particularly good”, or maybe the light bursts are used to freak out and evict some of the free-loading critters out their tubes if it starts getting too crowded in there.

Many polychaetes and other invertebrates emit light when disturbed, either for warning/predator avoidance or for communication with potential mates.   The yellow bands shown here on a nereid “pileworm” may be bioluminescent areas of the body used for signaling.
nereid-yellow-banding
Polychaete worm behavior and physiology is as extremely diverse as their morphology.  For such “sleeper” creatures that are unfamiliar to most regular folks, polychaete worms actually have alot going on!


Filed under: Academy,Diving,Philippines,Piotrowski,Shallow Water,Uncategorized — cpiotrowski @ 4:39 am

May 8, 2011

Rubble with a Cause

While other Shallow Water researchers are busily gathering sea urchins, sieving sediment for sand dollars, spotting vibrant and cryptic miniature sea slugs, stalking elusive reef fish, and gardening the reef to harvest symbiotic barnacles, I….as odd as this is going to sound….am collecting rocks.

A tub of.....rocks???

A tub of.....rocks???

Not just any rocks, mind you….. specifically coral rubble rocks. Coral rubble consists of fragments of hermatypic (reef-forming) coral which, over time and during storms, have broken from the reef and rest on the seafloor, providing habitat and surface area for the settlement of new recruits.  I collect these coral rubble fragments in search of polychaete worms.

When diving on a coral reef, several fairly obvious species of polychaetes can be observed. Polychaetes are a highly diverse (about 10,000 known species) group of segmented marine “bristle worms” distantly related to earthworms and which occur in all habitats of all marine ecosystems.  Polychaete worms vary in size from a couple of millimeters up to 2 meters in length.  These organisms serve as an important food source for birds, fish and other invertebrates, function in symbiotic relationships with various other reef organisms, and may even bio-engineer reef environments.

Examples of polychaetes you may have encountered in photos or on reefs include the “Christmas tree worms” and “feather duster worms”. These two types of sedentary polychaetes can be easily observed living in tubes deeply buried within large sections of live coral.  Many other polychaetes are free-living and do not form permanent tubes.

Spirobranchus gaymardi, "christmas tree worms", on coral
Spirobranchus gigantea complex cf. gaymardi, “christmas tree worms”, on live coral
Sabellastarte indica "feather-duster worm"

Sabellastarte indica, "feather-duster worm"

We are strongly against destructive sampling activities that would adversely affect the reef, so I don’t collect these worms burrowed in live coral. Many of these are common species, anyhow, and are quite well-studied (although others may benefit from taxonomic revision or DNA comparisons with other populations).

However…let me tell you….the really interesting stuff is in the rocks! As I dive, I typically head for the “dead” looking section of the reef.  You know, the area you might pass over accidentally on your way to the cool-looking colorful stuff but would certainly not intentionally photograph because it’s all basically one greyish color and has little interesting macro-fauna living associated with it.
This is my hunting grounds.

Searching for worms under coral rubble

Searching for worms under coral rubble

I carefully turn over all the most interesting-looking rocks and coral rubble in the immediate area. Sometimes I get lucky and there might be an obvious larger animal sheltering under the rubble, using it for cover from daylight as it waits to forage at night. Other times, there may be a nice fat worm tube stuck to the underside of the rubble…that one’s a keeper.

Most of the time, though, I just select a few rocks that I think look particularly promising, bag them up in whirlpacks and add them to my collecting bag. My rock collection helps keep me stay neutrally buoyant as my tank grows lighter at the end of the dive, but if I go overboard on collecting heavy stuff our Dive Safety Officer, Elliot Jessup, is often around with a lift bag (similar to an orange partly-deflated balloon) to help me slowly transport my rubble to the surface.

Using a lift bag makes carrying rubble easy

Using a lift bag makes carrying rubble easy

Collecting rubble may seem like sort of a weird activity, and perhaps folks don’t get quite as worked up about admiring my catch of rocks at the end of a dive as they might, say, a cool new fish. However, after the rubble sits in the tub next to my microscope for a few hours, it becomes apparent that these chunks of rubble abound with tiny yet fascinating cryptic organisms. In most cases, animals that live within rubble remain hidden for part or all of their lives, and thus are less likely to have been studied yet by humans. We can learn a great deal about the true biodiversity of a coral reef from closely examining its rubble communities.

Each batch of rubble and all animals from it is labeled with data

Each batch of rubble and all animals from it is labeled with data

Small organisms use the crevices and spaces within rubble rocks for a hard surface to attach to or for a refuge that is safely hidden from large predators. Miniature food webs occur within a chunk of rubble.  Algae is fed upon by grazers, who may in turn be fed upon by small predators.  Many organisms live within rubble crevices for much of their reproductive lives, releasing gametes or buds into the water column from these safe confines during their reproductive periods (more about this in a future posting).

Syllidae, a small but striking worm from the rubble

Syllidae, a small but striking worm from the rubble

Eunice, another resident of rubble

Eunice, another resident of rubble

Communities of organisms inhabiting coral rubble have been used in scientific studies for measuring diversity, productivity, and general reef health. Some organisms living in these communities assist in the breakdown of the rubble itself, permitting the release of calcium carbonate into the water for use in building new reef structure.

Dorvilleidae, another worm from rubble

Dorvilleidae, another worm from rubble

For me, examining coral rubble is an excellent way to sample for the small and cryptic “sleeper” critters  (such as polychaete worms) which live hidden lives buried deep within the reef ecosystem, quietly providing critical services to the community.

Once I have my samples, I can return the rubble back to the seafloor to be colonized again.


Filed under: Academy,Diving,Philippines,Piotrowski,Shallow Water — cpiotrowski @ 4:16 pm

May 2, 2011

First week of the Expedition

After a nice long redeye across the Pacific Ocean we touched down just after sunrise on Luzon, the largest of the more than 7,000 islands that make up the Republic of the Philippines.

Arriving in Manila

Arriving in Manila

Our team of seven researchers spent two full days in Manila dealing with logistics, picking up last minute supplies for our work at the field site in Mabini/Anilao, and interacting with local officials and scientists.  Walking and driving around this modern bustling city it was easy to comprehend that more than 11 million people live within Metro Manila.  With so many autos on the roads (and the associated traffic gridlock) the government has instituted a coding system in which cars with certain license tag numbers may not drive on particular days of the week.

Jeepneys, brightly painted military-style jeeps commonly used as mass transit (a tradition held over from the post-war period) and the tricycle taxis made for a very colorful excursion through the city to our destinations.

Jeepney on the streets of Manila

Jeepney on the streets of Manila

We “divided to conquer” with half of us heading off to meet with government officials to confirm permits and the other half setting off to organize the 46 large boxes of field supplies that we’d shipped to the Philippines National Museum from San Francisco (which somehow now seems like a galaxy far far away).

Philippines National Museum

Philippines National Museum

Loads of supplies!

Loads of supplies!

Visiting museums is always fascinating…but it’s even more interesting for museum workers to learn how other collections are curated. We met with the Curators of Crustaceans, Sponges, Fish, and best of all…Polychaetes (marine bristleworms have their own department here).  We also had the opportunity to meet with the new Director of the National Museum, who expressed his full support for this expedition and future collaborations between our institutions.  We do hope to be back!

meeting with curators and Director

Meeting with Curators and Director

Once everything was squared away in Manila it was finally time to head out to the field.  We piled ourselves and our equipment into three tightly-packed vehicles and headed south through lush farmland and lovely countryside towards Mabini.

Our first view of the ocean was exhilarating…now THIS was what we had come to explore!  We arrived at the field site and got settled in right away, everyone working to load our supplies down the steeply sloping property using a series of stairways.  One of our outrigger dive boats was on-hand at the shoreline when we arrived to complete the idyllic view from the field site.

one of our dive boats

One of our dive boats

It didn’t take us very long to get underwater….just a quick lunch and a dive briefing and soon-after we plunged into the waters just offshore to test out our brand new Oceanic gear.  I was amazed by how diverse the reef appeared right off the resort area!

We were even more amazed over the next few days as we explored several dive sites in the region.  Beautifully colored walls of corals, feather stars, huge vase sponges, pipefish, sea snakes, lionfish seemingly under every ledge, huge mantis shrimp scuttling furiously to reach their burrows, and vibrant nudibranchs just about everywhere you look (at least more than I’ve seen before on one dive).  And so many species still to be described!

Anemone fish

Anemone fish

Night diving is an entirely unique experience since different animals are active at night than during the day.  We spent some time “muck diving” the other night in an area near a sulfur springs with a mixture of sand, gravel, and mud.  As you might imagine, muck diving can be quite fruitful for someone who studies worms.  Sure enough, two fireworm species resulted from this dive.

Most species of fireworm remain hidden under coral rubble or rock during the day but can be found crawling across the sand at night in search of food. While many fireworms are “slow” carnivores that feed on sedentary animals such as corals, anemones, and sponges…the fireworms we’ve encountered so far are in the genus Chloeia and are actually thought to feed on carrion.

the fireworm Chloeia fusca

The fireworm Chloeia fusca

Fireworms can present a bit of a challenge to work with, as their bodies are equipped with long, very brittle bristles that lodge themselves in your fingers if you touch them and will remain embedded there for days producing severe  irritation.  Studies suggest that the bristles of at least some fireworm species may be filled with a mild neurotoxin that enhances this irritation.

We get around this by not handling them, obviously.  Forceps or a nearby rock are always handy!

We found a second species in the genus Chloeia during the same night dive.

another fireworm Chloeia flava

Another fireworm species Chloeia parva

Stay tuned for more images and news from the field over the coming weeks.  We’ve just gotten started!


Filed under: Piotrowski,Shallow Water — cpiotrowski @ 4:51 am

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