The Sulfur Seeps of Maug

We woke today to squalls covering Maug, a group of three islands that form the rim of a submerged caldera of an ancient volcano.  There are no known eruptions since the discovery of Maug in 1522 but the NOAA Vents program has been exploring the Mariana Trench area for submerged volcanic activity.  The caldera is about 1.5 miles wide and averages 600 feet deep with a twin-peaked lava dome that rises in the center to within 60 feet of the surface.  Our dive sites are located both inside and outside of the caldera with one hopefully planned for the lava dome area.  

The most spectacular site of the day was on the inside edge of the north island.  We dropped into an area that had 100% coral cover for as far as the eye could see.  The coral, Plate and Pillar Coral (Porites rus), extended from the top of the reef slope at 20 feet to at least 100 feet deep (after which we couldn't see the bottom).  As we followed the slope around a bend, we came to an area that looked like a land slide of orange mud and was completely devoid of coral.  As we got closer, we noticed that there were little bubbles coming up from the mud and when I put my hand down, it was hot to the touch.  We had found sulfur seeps!  We took time trying to snap pictures of the bubbling mud and one of our scientists even went barefoot, just to wiggle her toes in the sand.  Too soon it was time to go back to the surface for more rain squalls and a trip back to the ship.  We will be at Maug for the next two days and I'm looking forward to what else it has in store.

I hope your night is going well.  Here are a few pictures to keep you going ...

Take care,

Cristi

Plate and Pillar Coral


Purple Queen Fish and a Cleaner Wrasse


Entering mud slide area

The bubbles are sulfur coming from submerged volcanic activity


One of our scientists refusing to come up from the dive and into yet another rain storm

Uracus and the Steves

Our dive sites today were at Farallon de Pajaros (Birds Rock) or Uracus; the northern-most island in the Marianas Archipelago that covers less than a square mile and is slightly south of Iwo Jima, Japan.  Like the other islands that we've visited since leaving Saipan, Uracus is an active volcano being caused by the Philippine Sea tectonic plate moving onto the Pacific plate.  It's most recent eruption was in 1943 but the island is still mostly devoid of plants, so there is nothing to prevent runoff of soil and rocks into the water.  We noticed the effects of this immediately upon starting our dives.  Visibility was very limited, especially within the top 20' feet of the surface.  We would descend through a murky cloud of green that would open up to slightly clearer water at 40-50 feet depth.  One of the sites was so murky that a team who was working within feet of a transect line - watching the line - looked up to check on the other divers and were not able to find the line when they looked back down.  They finally had to surface, swim back to the float marking the start of the line and try again.  The underwater sites left a bit to be desired, probably because of the large amount of sedimentation from the land. All of the dive sites were covered in black sand and large boulders without much coral or algae.  

However there were highlights to this island.  On our second dive we were visited by a large school of Spade Fish.  This is probably the best fish that I've seen so far on this trip.  They were between 1 and 1.5 feet in diameter, taller than they were long, and extremely curious.  After I returned to the ship, I was informed that they are named Steve - all of them.  So the school of Steves checked us out for a little bit while we were working and one stayed with us for the rest of the dive.  It was great and more than a bit distracting while trying to work.  I kept wanting to watch what Steve was doing instead of collecting data.

Meet Steve...

...and his friends

I am off to bed for now.

I hope you have a wonderful evening,

Cristi

More time at Pagan

Pagan's North Volcano

Good morning,

We are at Pagan for our third and final day.  After this we move on to Asuncion Island.  There is nothing much to report for now.  Diving has still been good and the weather is holding.  We woke up to another glassy day without as much as a whitecap in sight.  I love those mornings.  The sun was rising over the volcano which made for a wonderful backdrop while prepping dive gear.  I am hoping that we will get to go on island this afternoon, but I'm not sure.  We have three of the Team Leads on our boat and they tend to be less adventurous than the rest of us.  Who knows, maybe they will be up for a swim and beach landing over lunch.

I better be going for now.  We have our morning meeting in just a few minutes.

Take care and have a wonderful day,

Cristi

Our Boat

Pagan Island

Pagan at sunrise

Today we moved on to Pagan Island; two volcanoes joined by a narrow strip of land with one that is still smoking from an earthquake a few months ago.  The island is ~ 18 square miles in total area and is the fourth largest in the Northern Marianas Chain.  It was inhabited in historic times, however a 1981 eruption forced all inhabitants to evacuate and no one has returned.  There are still a few buildings remaining and wild cows and pigs that were left behind.  The above-water landscape is amazing with sea cliffs, black sand beaches, coconut palms, and ironwood trees with a bare cinder cone in the background.  The underwater portion is less than spectacular.  I was surprised but our first dive site was covered almost entirely in a type of bacterial mat that normally only forms when there are too many nutrients in the water.  I am curious to see if this is the case, possibly from recent volcanic activity?  I’ll have to ask the oceanographers after they analyze their water samples for nutrients.  The water is also very warm, 84, so that may have something to do with it.  The second and third dives were boulders in black sand with more coral colonies perched on them.  The highlight was seeing the tow team twice underwater.  It is becoming quite familiar to hear the distinctive whir of their engines as they are now making a habit of including our dive sites in their surveys for data consistency.  Most of the time when we hear that whir we stop working and start watching for the tow line so that we are not surprised when they come past.  When I am not paying attention, I have often felt someone grab the back of my SCUBA tank and start towing me along with them.  But this time I was watching and I was able to take my first towing lesson.  As Ben went past, he motioned to me to take the towboard as he hung on to a trailing line behind it.  Molly, my dive buddy had grabbed on to trailing line on the other board.  I loved skimming above the bottom, much faster than I could swim.  I had to remind myself that I had work to be doing and eventually Molly and I went back to our work.  I think I’ll be watching for the tow team more often.

The Tow Team

I hope you have a wonderful day,

Cristi

Sarigan

All of Sarigan

We had an incredible visit to Sarigan today, the first volcanic, uninhabited island north of Saipan that we've visited so far. This is a tiny island with one side composed of steep cliffs with black sand and boulders underwater.  The north west side of the island looked like a tropical paradise with a small beach and covered by coconut palms.  The dive site on the NW side was amazing.  It was a labyrinth of columns and ridges with incredible coral and fish life.  I was wondering if I could cancel the survey due to insufficient concentration.  At all three dive sites I noticed far more fish than in Saipan or any of the other inhabited islands that we've visited. Even the boulders were beautiful in their own way but the high wave energy of the area and hard bottom seems to prevent many corals from colonizing there.  This was a wonderful introduction to the Northern Marianas islands.

I hope you are doing well and enjoying the day,

Cristi

This is one of our small boats next to the cliffs.

Our first shark siting since Wake.  The area from Guam to Saipan is mostly fished out.

We were surveying between these columns and ridges.  You can see our transect tape in the middle of the picture.

This was the biggest beach we found on Sarigan.

Seeing Small Things

As a member of the Benthic Team, I document what I see along the bottom every 6 inches for a total of 150' at each dive site. This means that I spend most of my time with my head between coral heads and algae, so I miss a lot of the cool fish and what not that may be swimming past me. But one benefit of looking that closely at the bottom is that I get to see a lot of the small things that I would otherwise overlook. 

One such creature is the nudibranch. Literally its name means 'Naked Gills' which is appropriate because it breathes through a set of bushy external appendages on its back, sort of like wearing your lungs on your back. Nudibranchs, also sometimes called sea slugs, are a group of shell-less snails that live in all oceans of the world and at almost every depth. They are often very colorful but are easily overlooked because they are usually less than an inch long. They tend to be carnivorous, feeding on sponges, anemones, or other sea slugs and the 'horns' that you see at the front are actually sensory organs used for touch, taste and smell. They defend themselves either by blending into the algae or coral around them or by using bright colors to indicate that they are poisonous. I particularly like them because they're very photogenic and patient for the camera. These are what I've found so far on this trip.

Have a wonderful evening,
Cristi

The Blue Grotto, Saipan

After over a month at sea and 50 dives, we came into the port of Saipan. We had 3 days on land and we needed to work for at least 2 of them. So you may wonder what did we do on our day off? Go diving of course. Yep - I find this rather amusing myself, but Friday morning bright and early at 6am I was prepping dive gear. Eight of us piled into a minivan and made our way to a dive site called the Blue Grotto. When you drive up, you can't tell that you are near the water. From the parking lot, it looks like you are on top of a set of sea cliffs and a good hike inland from the coast. So we geared up next to the van and made our way down a staircase that opened up into a vertical tube with 100' cliffs, a pool of saltwater at the bottom (complete with crashing waves) and a rock in the middle of the pool. The trick is to clamber out onto the rock so that you can jump off the far side into 30' deep water. And like the little crabs that scurry back into the water when they are spooked, we all tumbled off the rock on the far side, more or less gracefully. From there you drop down to about 40' deep and you can see that the tube is fed by 3 massive tunnels leading out to the open water at the base of the sea cliffs. The tunnels themselves are ~ 40' high and 70' wide and are the real highlight of the area. Once out in the open we found a wave-scoured area with numerous fish, fan and wire corals. All of these have been sparse so far around other islands in this archipelago so it was a treat. We even found Nemo.

I am off to prep more dive gear for now. We are back at work around Saipan.
I hope you have a wonderful day,
Cristi