Microbialites

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Pavilion Lake Noises

Posted on July 7th, 2010 by Chris Hadfield

In the name of science we have invaded cottage country. The quiet cabins along Pavilion Lake have every bed filled, and there’s a tractor-trailer in the parking lot with NASA painted on it. Instead of fishing boats we have floating science platforms, torpedo-shaped robots, and 1-person submarines.

While digging into the world’s geological history we’re making an unusual racket in a peaceful place, and this is what I hear:

  • My roommate’s alarm clock is set to Stayin’ Alive by the Bee Gees. It seems a brutal sentiment at 06:45.
  • My bunkbed mattress creaks so loudly that I only roll over when I really have to.
  • Breakfast is a hubbub of voices, 50 scientists and researchers from all over, discussing Cheerio flavours and side-scanning sonar.
  • Many small fans cooling too many laptops creates a steady low hum in every room.
  • The technician’s voice is calm and steady as he reads me the submarine pre-launch checklist.
  • The thrusters on my submarine whir and whine, like a sputtering dentist’s drill.
  • Radio voices are too loud and urgent to be natural at the bottom of the lake. My own voice sounds alien down there.

The loons calling on the lake are haunting and perfect, and will reclaim the mountain silence as soon as we are gone.

Chris Hadfield

Colonel, Astronaut, submarine pilot

Exploring the Herms: Bekah Shepard

Posted on July 6th, 2010 by Bekah Shepard

Magical! Driving a sub through the “herms” of Pavilion Lake is absolutely magical! Imagine this: a snow of particulates streaks around the dome. A yellow light permeates the water column as it filters through the planktonic cloud and bounces through the Chara. Microbialites rise up from the bottom like castles shrouded in a mist of microalgae. The natural world is like poetry to an observational scientist, and a dive in the herms is high art. Of course, to someone who studies the shapes and forms of microbialites (like I do), a dive in the herms is also like candy! Microbialites cover up to 90 percent of the lake bottom, and exhibit a variety of different shapes in a space of only a few meters. For a microbialite scientist – Yum!

View from the pilot's seat.

Today I was lucky enough to pilot such a dive to the herms. The herms are an area near the center of Pavilion Lake. Their name is a bit of a misnomer – in fact, it is more of a nickname that stuck! Herms is short for bioherms, which refers to a build up of biological organisms, usually into a mound that rises above the surrounding sea or lake floor. Our Pavilion herms are mounds, but they are probably just sediment mounds that are covered in lots of microbialites, rather than being mounds build up exclusively by microbialites. Nevertheless, they remain a favorite area of the PLRP scientific team, because of the small area, dense ecology, and interesting geochemical and limnological environment.

My mission was to completely circumnavigate two of the herms that we had not mapped in previous years. Navigating the subs through an area of such dense mounds and interesting features has been challenging in the past. The topography can make communication between the surface and subs problematic, and our maps have not always been as accurate as they are now. However, as our research has continued, our knowledge of the area has improved, our communications infrastructure has grown by leaps and bounds, and I daresay, some of us are even getting better at flying these subs! I am proud to say that the circumnavigation went smoothly and we were able to fill in some missing areas in our maps of the herms!

Exploring the herms at 40 feet.

Improving our maps also means raising more questions; such is the nature of exploration, and this dive was no exception. Although many of the morphological trends that I observed were similar to those I have noticed before (adding strength to some of our hypotheses), new subtleties leapt into view. Why, for example, do many of the microbialites along the bottom of the mounds look roughed-up, slightly broken, whitish, and all together kind of crummy? Does it have to do with fluctuating sediment levels at the bases of the mounds? Perhaps. That leads me to questions of how precisely sediment is transported around the mounds: what is the source of the sediment? How often do large sediment flows come down from the surrounding walls? Are the microbialites buried and exposed regularly or does it happen on a timescale of decades or centuries!? For each answer there are new questions, and for each new question there are a handful of associated questions.

Returning to the surface to see a smiling Susan Winnitoy, guiding me back to the barge.

The abundance of new questions is thrilling, and is what keeps bringing us back here. I often find myself chatting with people who are surprised that we haven’t uncovered all of the details of microbialite formation, development, and growth – after all, we have been studying Pavilion Lake for a number of years. Yet that is the appeal of studying microbialites! Microbialite mounds are subject to nearly countless variables – biological, chemical, and physical processes that change through time. Untangling each of those influences is a process – a process that is being helped along by the phenomenal amount of data that we are collecting with the DeepWorker subs, with the GAVIA AUVs, and with our team of SCUBA divers. So, do we understand everything about microbialite formation yet? Nope. Not by far. But with dives like my magical one through the herms, we are getting ever closer! The microbialites of Pavilion Lake have a story to tell, and through our exploration we are listening to the telling.

- Bekah

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Happy Canada Day! This blog rocks!

Posted on July 1st, 2010 by Mary Beth Wilhelm

Hello from Pavilion Lake and happy Canada Day!! My name is Mary Beth and I am one of the more junior members of the PLRP team. I am half way through my undergrad at Cornell University in New York and am an intern at NASA Ames Research Center in California.

I just arrived back to land a half hour ago after being out on the lake for over 6 hours! And while it was a lot of fun to be outside, I had to pull out my jacket that I only use during the winter in New York. It has been a very busy day as the PLRP team conducts a full suite of submersible, autonomous underwater vehicle, and SCUBA dive operations.

I had two major jobs today. The first was keeping a log of all of the science notes that sub pilots called up to the surface while following the sub in a boat that is equipped with walkie-talkies capable of communicating with the pilot while he was underwater. Astronaut Mike Gernhardt was piloting one of the subs today, conducting an extended 5 hour dive around the south basin. It was exciting to listen to all of Mike’s observations and discoveries in real time!

My second job today was taking rock samples for my own summer research project. I am investigating the role of rocks in the formation and morphology of microbialites. We think that microorganisms may prefer to start forming microbialites on solid surface substrates, like rocks, and our team has observed many microbialites throughout the lake that have formed on top of both really big and small rocks. Pilot Margarita imaged rock slides of interests in the DeepWorker subs on Monday, and after reviewing the data with the science team, we decided to revisit a few of these slides with divers to collect rocks to study. So, today I had pro divers Mike D. and Gary take a few rock samples every 10 ft. from a rock slide in the central basin that went from about 80 feet below the surface all the way up to the shore.

After collecting these samples, I will analyze them in our outdoor wet lab, recording basic physical observations and measurements, and looking for trends in the data that will help us understand how factors like size of the rock and depth may affect microbialite growth. Hopefully my observations will help elucidate factors that control microbialite growth on rocks and even give us more clues to how microbialites are first formed.

-MB

Boy meets microbialite

Posted on June 30th, 2010 by Tyler Mackey

Today was my first research dive of the 2010 PLRP season, starting a project on microbialite morphology. I am a geology graduate student from UC-Davis and, while I’m not a true microbiologist, my thesis work is focused on the potential signatures that their communities can leave in the rock record.

Side view of the MOUS showing vertically oriented growth structures (note lasers are 10cm apart)

Growth processes in the Pavilion Lake microbialites may give insight into the significance of ancient microbial carbonates. I’m particularly excited to join the PLRP crew because of the wide range of microbialite morphologies that are present here. In the course of the next two weeks, I will be diving on one particularly large microbialite, affectionately dubbed the MOUS (microbialite of unusual size). The carbonate structure is apparently templating a boulder from a rockslide. While today was mostly an exploratory dive to photograph and survey the structure, I will mostly be investigating the relationship among light regime, microbialite morphology, and invertebrate grazers.

Above the MOUS with blocks of microbialite

Locating the MOUS underwater was our first task of the day. We dropped down near its recorded location and then followed the lake bottom down along a landmark rockslide until we reached 85 feet. From previous dive records, we knew that the top of the structure was at 87 feet, so we swam parallel to shore until we intersected it. The visibility in Pavilion Lake is great (particularly as I’ve done most of my training off of Northern CA) so it was pretty easy to spot.

Sediment deposit with surrounding growth on the top of the MOUS

While my dive buddy, Mike Delaney, worked putting in a temporary transect line to help us more reliably locate the structure (particularly during night dives), I photographed some of the major regions. Large blocks have spalled off the side of the structure throughout its growth, forming an incipient conglomerate of sorts at its base. I’d love to see this in the rock record!

Mike Delaney installing temporary transect line

One of the aspects of modern analogues that really fascinates me is time-averaging. What we see here on the surface of the lake is a geological instant, and over time the current growth surface will be incorporated into the microbialite subsurface. What would this look like? Outside of this project, one of my broader research questions is determining what sort of paeleoenvironmental record might be left in a microbialite, and how that signature is altered with preservation, or lack thereof.

I’m excited to learn more about the interactions between these microbialite structures and their surrounding environment as the field season progresses. There is always room for the unexpected in fieldwork, and I look forward to seeing what future dives will uncover in the lives of these microbial communities.

-Tyler

Editor’s note: Tyler’s boyish good looks have earned him the affectionate nickname “Boy” among the science team – resulting in the title of the blog entry.

Ask a Scientist: Are scientists looking for similar lakes around the world that might have these microbialite structures?

Posted on June 27th, 2010 by Margarita Marinova

Question from Astrobiology Magazine regarding other microbialite supporting lakes around the world. Answered by Dr. Margarita Marinova. To ask your question, visit www.astrobio.net and search for the Pavilion Lake Research Project, or click this link: www.tinyurl.com/askplrp.

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Meet Allyson: Acting Principal Investigator for 2010

Posted on June 9th, 2010 by Allyson Brady

As the 2010 PLRP field season draws nearer, we are all busy with plans and preparations. This summer will be a bit different for me as our fearless leader Darlene will be on maternity leave and I will be stepping into the role of acting Principal Investigator (PI). A daunting task, but I know I have the support of an amazing team of people and we’re all working towards having a fun, safe and successful field season.

Allyson in final preparation for a DeepWorker flight

Looking back over the last 5 years that I have been involved in PLRP I am in awe of what we’ve accomplished and how much we’ve grown. Last year we successfully mapped additional regions of the lake using the DeepWorker submersibles and re-visited areas of interest identified in 2008 for more detailed imaging and observations. We were also very successful in classifying a great deal of our DW imaging data while in the field. This was a huge accomplishment and the entire team worked very hard to make this happen, we hope to have a repeat this year. Examination of the 2009 data has helped us to identify more regions that show interesting trends that we will be exploring in this upcoming field season.

Flight planning for 2010 is going ahead full-steam! We are very pleased to continue with our astronaut training program this year and welcome Chris Hadfield and the Stan Love to the PLRP gang. I can’t wait to see their reaction to viewing this remarkable lake and the microbialites for the first time.

As always, there are a number of fundamental science questions that we are working towards answering through the exploration of this beautiful lake, not only with DW but with SCUBA and GAVIA as well. We will continue to examine questions regarding the role of biology and physical parameters in carbonate precipitation including: What are the dominant surface microbial and viral communities? Does grazing by macroorganisms affect microbialite morphology? What is the role of algae? How do depth and slope affect morphology? And many more… I’m looking forward to partaking in some great science and exploration activities this summer.

The field season is nearly upon us so stay tuned for more updates!

~ Allyson

Tracking submarines on the go!

Posted on July 15th, 2009 by Matthew Deans

For the past 10 days we have been making real time maps of all of the sub operations at Pavilion Lake. To do this, we have written some software to generate KML files to load into Google Earth. The Intelligent Robotics Group at NASA Ames has a lot of experience with ground data systems for NASA missions like the MER rovers, robotic earth analog field tests like the Robotic Recon test in northern Arizona in June, disaster response applications, and the Gigapan camera system, we were able to put together a set of tools to support sub tracking and mapping using a lot of existing software. We call the collection of tools and processes the “Surface Data System.”

Pavilion Lake 2009 Data Map

Pavilion Lake 2009 Data Map

We started with importing overlays of the bedrock geology from British Columbia Geological Survey (BCGS), as well as sonar bathymetry and sonar backscatter maps that show depth of the lake and structure of the bottom. These provide context for flight planning and for setting expectations for what we will find during the flights. In real time during the submarine flights, we get sub position every 5 seconds from the navigation computer on the chase boat. We use that to track the sub by periodically writing out updated KML files and automatically refreshing them in Google Earth as network links. A submarine icon shows the current location of the sub, and a compass rose shows bearings to indicate which way to go to reach the next waypoint. Google Earth also provides lots of measurement tools, annotation tools, and other built-in functions that we can use to annotate and analyze the map. All of this information is saved to a shared filesystem so that everyone at the camp has access to all of the same map data.

We have established an operations role on the support vessels which we call the “Science Stenographer”. That person’s job is to listen in on the voice loop and transcribe any significant observations in real time. Observations worth calling up to the surface immediately appear on the map as icons that you can click on to read the date, time, lat/long, and what was said.

My reflection in the monitor showing the stenography program

My reflection in the monitor showing the stenography program

In addition, the submarines are recording video continuously. The video recorder also has an “event” button that can mark the timestamp of a significant event on the video. In post-processing, we cross-correlate the timestamps to get position, and put a preview image and compressed video clip into the map as well.

These maps have been very useful for operations, for post-flight analysis, and for planning the next set of activities. After the flights are over, the science back room immediately has the flight track as-flown and georeferenced notes from the pilots. After some video post-processing (which takes some time simply due to the quantity of data: over 25 GB of video from each flight) the video clips and video stills are georeferenced and in the map. This information has been used to modify or create flight plans in real time. As an example, one morning Margarita identified interesting sampling locations during her flight. The post-flight map was immediately used to create a second flight plan to send Ricky to those locations for sample collection that same afternoon. It has also been interesting to see all of the flights and notes and images on one map simultaneously. The team realized before the end of the field season that there were areas of the lake that had not been covered and could plan accordingly.

Georeferenced notes attached to the flight tracks in Google Earth

Georeferenced notes attached to the flight tracks in Google Earth

Without this real time information procesing and integration, it would have been too late to go back and investigate those areas during the field season. Those flight plans would have to wait for another year. In a field setting with a lot of logistics overhead and a short duration for field work, understanding the big picture of operations quickly is a big time saver.

Georeferenced tree image in Pavilion Lake

Georeferenced tree image in Pavilion Lake

After the field season is over, the map data will be used by the team to analyse and correlate information from across the lake and across different flights to support their research, and to plan next year’s activities. All of the observations and information gathered this year bring up new questions and new hypotheses, and there is always more to study in this lake.

The images in this post show a few different views of map screens. There is also a

KMZ file that you can download and open in Google Earth to see one of our flight plans and watch the time lapse animated flight track for the actual submarine positions flight as it was flown that day. Try setting the playback speed to the minimum for best results. Enjoy!

- Matt

DOWNLOAD THE KMZ FILE

What Did You Do On Your Summer Vacation?

Posted on July 14th, 2009 by Bree and Jen

This is a question that we ask our students on the first day of school in September. Boy, we have some interesting things to share on our first day of school. This summer, we travelled together to the Pavilion Lake Research Project to learn about the science that is being done here and how it can be incorporated into the classroom. During the year Bree and I are both immersed in the classroom, and most of the time we are teaching science. Today we have found ourselves writing a blog which neither of us have done before. We seem to be entertaining the people around us with our different ideas of how best to compose one of these, and we will find out if we get a gold star later. The crew here have been very welcoming and happy to share about what they do here. In fact, our first night here we were allowed to get inside one of the DeepWorker submersibles which are used during the scientist flight missions (we were still on dry land, but still very cool). Part of us being here at Pavilion Lake was to integrate teachers into the different activities that go on here, and integrate us they did.

From left, Bree Riddell, Ricky Arnold and Jen Stonehouse

From left, Bree Riddell, Ricky Arnold and Jen Stonehouse

So we are sure you are wondering what we were were able to do at the lake. Unfortunately we were not allowed to drive the subs but we had many other cool opportunities to be part of the team. We sat in on science meetings, pilot meetings, classified data from the submersibles, talked to scientists and astronauts, observed the launches of the submersibles and helped record data from the flights as a science stenographer. One of things that we did was classify the images returned from the underwater flights. During the flights images of what the pilots see is recorded on camera. The pilots see very cool things when on their mission – microbialites. After the mission this data then has to be classified. We looked at images to identified what was in the image – microbialites, algae, rocks, sediment, trash – oh my! This is something that can easily be transferred to the classroom. We classify every day just like the scientists (just on a different level). As the team here classifies these images for science and further understanding, students can also classify these images in the process of learning how to do science. Trust us (or read the rest of these blogs if you don’t), microbialites are very interesting!

How did we do with our first blog? Did we get a gold star?

-Jen and Bree

Why do the microbialites have different shapes?

Posted on July 10th, 2009 by Dawn Sumner
Different microbialites have different shapes.  Why?  How do we even answer this question?  One approach is to look at the building blocks of microbialites – the legos that stack together to make the structures.  Some microbialites have little tufts on them that make the surface rough.  These tufts are composed of the mineral calcite, which is intermixed with long, hair-like bacteria that come in two colors, pink and green.  The calcite makes the microbialite a rock, and the bacteria shape the tufts.  They are all lined up, pointing upward into the water like spiked hair.
These tufts are one of the building blocks for the microbialites.  How many there are, how they are arranged, and how fast they grow help shape the microbialites.  Lots of closely spaced tufts growing quickly create rough surfaces on the microbialites.  If the tufts grow slowly and there is lots of calcite, they only form small bumps.  If they are absent, the microbialites are smooth.  These smooth microbialites might need a different building block to form, one we haven’t identified yet.
The bacteria that form the tufts are photosynthetic – they use light to grow.  The tops of microbialites get more light than the sides do.  We can measure this, and it’s true in Pavilion Lake.  If tufts grow faster with more light and there is more light at the tops of the microbialites, we can predict that the tops might grow more quickly than the sides.  We haven’t measured this because the microbialites grow very slowly, and growth rates are very hard to measure.  However, the shapes of the microbialites suggest that they mostly grow upward.  Many of them have ridges on their sides pointing up or “chimneys” on top.  Thus, our prediction is consistent with the data we have so far.
Do we now understand why different microbialites have different shapes?  Nope!  The tuft building blocks that we’ve been analyzing should all behave about the same on near-by microbialites.  But the near-by microbialites aren’t all the same shape!  Maybe some of the differences are due to differences in growth rate, but I think there are probably more building blocks that we haven’t described yet.  To make a lego boat, you need different blocks than you do to make a lego submersible.  To make a dome-shaped microbialite, you might need different blocks than you do to make an “artichoke-shaped” microbialite.  We still have a lot to learn.

Different microbialites have different shapes.  Why?  How do we even answer this question? One approach is to look at the building blocks of microbialites – the legos that stack together to make the structures.  Some microbialites have little tufts on them that make the surface rough.  These tufts are composed of the mineral calcite, which is intermixed with long, hair-like bacteria that come in two colors, pink and green.  The calcite makes the microbialite a rock, and the bacteria shape the tufts.  They are all lined up, pointing upward into the water like spiked hair.

Close-up depiction of smooth and rough microbialite surfaces

Close-up depiction of smooth and rough microbialite surfaces

These tufts are one of the building blocks for the microbialites.  How many there are, how they are arranged, and how fast they grow help shape the microbialites.  Lots of closely spaced tufts growing quickly create rough surfaces on the microbialites.  If the tufts grow slowly and there is lots of calcite, they only form small bumps.  If they are absent, the microbialites are smooth.  These smooth microbialites might need a different building block to form, one we haven’t identified yet.

Smooth Microbialite Surface

Smooth Microbialite Surface

The bacteria that form the tufts are photosynthetic – they use light to grow.  The tops of microbialites get more light than the sides do.  We can measure this, and it’s true in Pavilion Lake.  If tufts grow faster with more light and there is more light at the tops of the microbialites, we can predict that the tops might grow more quickly than the sides.  We haven’t measured this because the microbialites grow very slowly, and growth rates are very hard to measure.  However, the shapes of the microbialites suggest that they mostly grow upward.  Many of them have ridges on their sides pointing up or “chimneys” on top.  Thus, our prediction is consistent with the data we have so far.

Closeup image of Microbialite

Closeup image of Microbialite

Do we now understand why different microbialites have different shapes?  Nope!  We still have a lot to learn, and many of the questions surrounding microbialite formation remain unanswered. The tuft building blocks that we’ve been analyzing should all behave about the same on near-by microbialites.  But the near-by microbialites aren’t all the same shape! Maybe some of the differences are due to differences in growth rate, but I think there are probably more building blocks that we haven’t described yet.  One thing to think about before I finish: To make a lego boat, you need different blocks than you do to make a lego submersible.  To make a dome-shaped microbialite, you might need different blocks than you do to make an “artichoke-shaped” microbialite.  This kind of thinking might help us solve one of the big mysteries of Pavilion Lake!

-Dawn

At Home in the Herms

Posted on July 9th, 2009 by Bekah Shepard

If you want to make a bunch of Pavilion scientists excited, just mention “the herms”. I just did my second submersible flight through the herms and it was spectacular! Let me give you a little background, so that you can understand why the flight was such a treat:

A bioherm is a mound constructed by biological organisms. A classic example is a patch reef: a decimeter to meter scale mound that is built by corals, sponges, and other reef animals. You may not think of a mound of organisms as being very sturdy, but just as your body is capable of making hard bones, other organisms such as corals also make hard skeletons. When those skeletons start to pile up, you get a bioherm – a biological mound!

So, what in the world does this have to do with microbialites. Remember that microbialites are “organosedimentary structures”, meaning they are built up of minerals that are influenced by organisms. “Whoa!” I hear you cry, “Does that mean that a microbialite is a bioherm? Well, a single microbialite is not usually defined as a bioherm, but if you pile up enough microbialites, you do end up with a mound that is constructed by organisms! By that definition there are some places in Pavilion Lake where we observe large piles of microbialites that can be defined of bioherms.

Thinking about microbialite bioherms is something that some of us geologists do quite frequently. Long before the organisms that build coral reefs evolved, big bioherms and reef structures still existed. Rather than being built by corals, sponges, or even shells, the ancient bioherms and reefs were built out of microbialites! Can you imagine SCUBA diving or piloting a submersible around ancient microbialite bioherms and reefs! Boy, I wish I had a time machine. Since I don’t have a time machine, I do the next best thing. Can you guess what that is? Yup, I come here and study the microbialites in Pavilion Lake. The details we learn about the microbialites in Pavilion Lake will help us to understand the fossil record of ancient microbialite reefs. That will help us to understand how life evolved on early Earth! Crazy cool stuff!

Ok, back to the Pavilion Lake herms. Here is where we are going to get really confusing! The “herms” are not actually bioherms, hence the lack of the “bio”. The herms are an area of sediment mounds at the southern end of the central basin of the lake. Now I know you are screaming, “but if they aren’t bioherms, which are so cool, why are you crazy scientists so excited about them!” It turns out that even though the herms are just sediment mounds, they are covered by some of the most interesting microbialites in the lake. There are a lot of different microbialite morphologies crammed into a very small space. If you start at the bottom of any given herm, you can often see several distinct morphotypes just by looking up two meters of slope. Likewise, if you move around a herm several meters, you often can see changes in morphotype or surface texture. Those are rapid changes! I’m sure you are asking yourself why the microbialites would be changing that rapidly, and that is one of our big research questions this year! It may be that the mounds are a place of significant environmental variability. In other words, there may be interesting water flow patterns, light conditions, variations in sedimentation, etc. that are unique to the herms. Any of these variables may be influencing the morphology of the microbialites! In short, the herms are a really complicated place, and if you haven’t figured it out yet, the scientists as Pavilion Lake love to study really complicated and interested places!

-Bekah