Mangroves, Mud, and More

September 2nd, 2014 by David Lagomasino

Mangrove forests

Flying over the Colombian Andes from Medellin to Nuqui in a small, 20 passenger propeller plane, five scientists peer out the window to look at the bosque (Spanish word for forest) covering the mountains below for as far as they could see. I was one of those scientists. Dotted throughout the forest, I can see indigenous communities thriving in small clearings with smoke billowing from small fire pits. Then, out of nowhere, the mountains drop off, the Pacific Ocean appears, and the plane banks hard to starboard. Finally! My first glimpse and the reason why I was making a trip out to Pacific coast of Colombia: mangroves.

My first trip to Colombia and I get to see some of the most pristine mangroves in the world. Why am I so excited about mangroves? There is something about the smell of the swamp, the harsh conditions, the incredible resilience of the trees, and the complex hydrology that draws me in. Mangrove is the general term used for a group of salt-tolerant tropical hardwood trees. Large communities of mangroves form unique forested ecosystems unlike any other forest found in tropical, temperate, and boreal climates. Though they only cover 0.1% of the earth’s surface, mangrove forests remove more carbon per unit area than any other terrestrial forest, which in turn, may be extremely important with respect to climate change and increasing CO2 concentrations. Most of that carbon from mangroves is sequestered by the thick layers of organic-rich soil that have been deposited and, most importantly, remains in these environments. Mangroves also provide a number of ecosystems services that can add up to billions of dollars in economic value per year. Some services are obvious like fishing, shrimping, timber and other raw resources. Other services are much harder to value but are still extremely important such as coastal protection, cultivating biodiversity, and cultural services. Despite their economic value or maybe because of it, mangrove forests are disappearing faster than any other tropical environment, including terrestrial forest and coral reef ecosystems, because of deforestation, coastal development and other human manipulations.

My trip was part of Vulnerability Assessment of Mangrove Forests in the Americas, a project funded by NASA’s Land Cover and Land Use Change Program and led by Dr. Marc Simard from NASA Jet Propulsion Laboratory (JPL). The project was designed to identify changes to mangrove forest ecosystems through time and space, and to understand how human activities coupled with land use/ land cover (LU/LC) change have altered mangrove environments. Researchers from NASA JPL, NASA Goddard Space Flight Center, Louisiana State University (LSU), and Indiana University (IU) have visited six sites over the course of the three year study to collect detailed mangrove and socio-economic data. This data is instrumental for developing regional models that can be adapted for diverse communities to assess mangrove vulnerability to human and climate drivers.

Our trip to Nuqui, Colombia was an effort to collect field data in pristine mangrove forests along the Pacific coast of the Americas, a location in which scientists know very little about the extent, height, and condition of the mangroves. The field data, which included tree height and tree thickness, will be used to help calibrate and validate or, in other words, make adjustments to and verify our mangrove structure and biomass models developed using a combination of remote sensing techniques. These remote sensing models use a series of mathematical relationships to estimate such things as tree height, biomass productivity, and carbon sequestration. The other collaborators on the project from LSU collected soil cores while IU initiated a locally-lead program to conduct socio-economic surveys. Fifty centimeter soil cores were collected at each of the sites to determine the amount of carbon found in the ground, which is the largest reservoir for carbon in these ecosystems. Socio-economic activity and demographic information collected from detailed surveys will help us to understand the relationship between the human environment and the changes to the mangrove forests.

Figure 1

(Top left) Skype meeting between NASA JPL interns and researchers from MarViva about remote sensing of mangroves. (Top right) Team America reading about the “Plan de Manejo Manglar.” (Center) Mangrove presentation to the community leaders of Nuqui. (Bottom left) “Mangrove 101″ with Edward Castañeda, from LSU. (Bottom right) Team America preparing for meeting with community leaders.

Before any scientific trip to another country, there is a ton of planning and connecting with local agencies to help ensure that you don’t run into any complications. Shortly after our arrival in Nuqui, Colombia, we checked into our hotel and began working on a presentation to show to the local leaders from several small pueblos that comprise the coastal region of the municipality of Nuqui. The presentation was to let the communities know; 1) why we were there, 2) why we are interested in mangroves, and 3) how our research will help the local communities.

The first two points were fairly straightforward. We had preliminary maps from the area which showed us that some very tall, 20-30 meter mangroves were growing in the region. We were there to “groundtruth,” or check out how accurate our modeled tree height estimates were and collect new data to develop better models. Very few studies have investigated mangroves along the Pacific coast and Nuqui was the perfect location to find intact forest ecosystems. Moreover, the coastal communities of Nuqui are dependent on many of the ecosystem services provided by the mangrove forests which include timber/ raw materials, fisheries, coastal protection, and water purification. We tend to forget that we are also part of the ecosystem, and that our actions will have a direct impact on changing the landscape. Nuqui has realized this and has carried out a “Plan de Manejo de Manglar (Mangrove Management Plan)” in the area of Tribugá. The plan includes three “zonas”: de uso sostenible (sustainable use), recuperación (restoration), and preservación (preservation). Mangroves are a necessary part of the coastal Colombian life and rooted deeply into their culture, so much that even the Vice-President of Nuqui, Enrique Murillo-Palacios, was moved to sing about his appreciation for those beloved trees during a dinner we had been invited to.

Mangroves Figure 2

(Top left) Walking home after a long field day in the rain. (Center) Marc Simard, from NASA JPL, measuring tree height. (Top right) Marc Simard showing Hector, from MarViva, how to use the inclinometer. (Bottom left) Cutting soil cores with MarViva and the Vice-President of Nuqui, Enrique. (Bottom right) David Lagomasino, from NASA GSFC, measuring tree diameter above the mangrove prop roots.

We addressed the third objective of our meeting, to show how our research will help the local communities, by working with local community members and local Nonprofits in the field. In addition, we also shared data between groups; some data we collected and other data that MarViva had been previously collecting. Over the course of the field campaign, a handful of local community members and two researchers from MarViva came with us out in the field to collect data. All the groups had their own area of expertise. The locals knew the layout of the land; where the shoals were along the river, where the tallest mangroves were, and a detailed background of the area. MarViva had permanent plots set up at various mangrove sites in the area of Tribugá. And Team America (inside joke: name for the US collaborators of the project) had the expertise in remote sensing, spatial statistics, and mangrove physiology.

While we were out in the field, we showed the locals how to measure tree height using inclinometers, measure tree thickness using diameter tape, and how to collect soil cores. Simple geometry has been integrated into the inclinometer and diameter tape. The inclinometer can estimate tree height by measuring the angles to the base and top of the tree from a set distance from the tree. Two triangles can then be drawn from these measurements using geometric techniques and, voila!: tree height. Old-school surveyors did this all by hand, but nowadays there are fancy inclinometers that integrate all the measurements in a single device with one output… tree height. The diameter tape also integrates geometry by using the relationship between the circumference and diameter of a circle. Collecting soil core tends to be a little more rudimentary, but one must consider a few technical issues first, such as soil compaction and suction, before just hammering a PVC pipe into the ground. From the soil cores we can obtain information about the rate of deposition, the amount of biomass, and the concentration of carbon in the ground. Getting muddy from field work can be one of the best parts of a project. Plus it’s always fun to parkour across a jungle-gym of mangrove prop roots.

Mangroves Figure 3

(Top left) Run-in with a pod of Humpback Whales during our initial site visit. (Top right) Asher Williams and Edward Castañeda, from LSU, learning about a new species of mangroves we had never seen before. (Bottom left) Always, always take a picture of your field book. (Center) Asher admiring one of the only black mangroves (Aviecennia germinans) we came across at our field sites. (Bottom right) Fruit from a mangrove tree.

Edward Castañeda, from LSU, gave an impromptu “Mangrove 101” course to local volunteers while we were taking a break in the field. Professor Castañeda discussed the various physical adaptations that mangroves have developed to cope with the harsh saline environments and remove the high concentrations of salts in the water. Some mangroves can thrive in water with salinities above 90 parts per thousand. That’s almost three times the salt concentrations found in the oceans! There are three main mechanisms that mangroves have developed to allow them to live in salt water: salt exclusion, salt excretion, and shedding. Salt exclusion occurs at the roots where thin membranes prevent salt from entering into the xylem. The excretion technique removes excess salts using glands found in the leaf. You can actually taste and see the salt on the undersides of some leaves. Lastly, some mangrove species can store excess salts in glands from “sacrificial leaves” that fall to the ground, removing the accumulated salts from their system.

Mangroves Figure 4

(Left) Always know where your lines of egress are. (Top) Transportation out of Nuqui. (Right) Marc Simard, from JPL, admiring the mangroves while on a boat ride to our next site. (Bottom) Almost lunch time in town of Tribugá.

After a week of working with the local communities and long days of fieldwork, there were mixed feelings about leaving. Sure, we wanted to get back to hot showers and air conditioning, but being able to see the sites, that we primarily research remotely, we began to formulate more and more questions. What makes the mangroves so big? How does the hydrology influence mangrove communities and tree growth? How deep are the mangrove soils? How far inland to the mangroves extend? Though we may not have an answer for these questions now, it is through collaborations with local agencies and educating local communities that can help us to eventually address research gaps. Town members from Nuqui learned about mangroves and their importance to carbon cycling and MarViva learned about new techniques to survey their field sites. Team America learned much more than we bargained for. Not only did we collect lots of field data for our remote sensing biomass and socio-economic models, but we learned a lot about the culture of Nuqui and how truly important mangroves are in their/our lives.

I stare out into the forest from my perch atop a mangrove prop root, surveying the near-impenetrable entanglement of the forests’ footing. In the distance, calls of “Árbol H6, DAB 4.5, Altura 12 metros” are muffled by the rain. Then I remember that I climbed up here to measure the thickness of the tree… but first, let me take a #selfie.

David Lagomasino

“If there are no mangrove forests, then the sea will have no meaning. It is like having a tree with no roots, for the mangroves are the roots of the sea.”
-Thai Fisherman (Trang Province)

NASA in Alaska 2014: Preparing for the Trip North

September 2nd, 2014 by George Hale

A new NASA airborne campaign known as ARISE, or the Arctic Radiation – IceBridge Sea and Ice Experiment, will take measurements intended to help researchers better understand the role that clouds play in Arctic warming as sea ice conditions change. From Sep. 3 to Oct. 3, researchers flying aboard NASA’s C-130 research aircraft will measure incoming and reflected sunlight, thermal infrared radiation, ice surface elevation and various cloud properties to gain a better understanding of changes to the Arctic climate.

C-130 in hangar

NASA’s C-130 research aircraft sitting in the hangar at Wallops Flight Facility as it is being prepared for the ARISE field campaign. Credit: NASA / Christy Hansen

For the past few weeks, aircraft technicians and instrument experts have been preparing the C-130 for its upcoming trip to the Arctic. A large part of this process was installing and testing the scientific gear that the ARISE team will use to collect data on clouds and ice.

  • Ice Land, Vegetation and Ice Sensor (LVIS) – LVIS is a laser altimeter used to measure ice surface elevation. Data from this instrument can tell researchers about surface conditions below the plane.
  • Broadband Radiometer (BBR) and Solar Spectral Flux Radiometer (SSFR) – These instruments measure the strength of incoming and outgoing sunlight and thermal radiation.
  • Spectrometer for Sky-Scanning, Sun Tracking Atmospheric Research (4STAR) – 4STAR studies aerosol and cloud properties by measuring sunlight as it passes through the atmosphere.
  • Probes – The C-130 is also equipped with probes to measure properties like cloud water content and droplet size to better understand Arctic clouds.
Instrument equipment inside C-130

Land, Vegetation and Ice Sensor (LVIS) instrument and control racks aboard the NASA C-130 research aircraft seen during instrument integration at Wallops Flight Facility in Virginia. LVIS is a laser altimeter that will be used to measure land and sea ice elevation during NASA’s ARISE campaign.
Credit: NASA / David Rabine

Once the instruments are installed and tested on the ground, the ARISE team carried out a pair of check flights – one to make sure the C-130 is flying in peak condition and one to verify that the mission’s various instruments are working properly.

C-130 flying a check flight

A view of NASA’s C-130 research aircraft seen from the T-34 chase plane during the ARISE engineering check flight on August 24, 2014.
Credit: NASA / Dennis Rieke and Mark Russell

For the next few weeks, the ARISE team will fly out of Eielson Air Force Base, Alaska, to collect data on Arctic ice and clouds.

Hurricane and Severe Storm Sentinel (HS3) 2014: Time for a new target: HS3 turns focus to the Bay of Campeche

August 31st, 2014 by Mary Morris

Since I last posted, AV-6 flew a successful mission over Cristobal. Meanwhile, AV-1 is still stuck in California until crews can figure out the electrical issues that are affecting the aircraft. Those of us on the AV-1 instrument teams, which includes the team I’m on, are starting to get pretty jealous of AV-6’s ability to actually fly. One of the most frustrating parts of being on an instrument team is waiting around until both your aircraft is available to fly and there is a good target for your aircraft to fly over. When we do get to fly, every instrument team has to staff the Global Hawk Operations Center, or GHOC. Thanks to multiple shifts of researchers and pilots, we can fly the UAVs for long lengths of time—all from the comfort of our desks! In the GHOC, researchers don headsets and monitor our instruments to make sure they are working properly; which is less flashy than it sounds. However, I still cannot wait to be a part of a flight. I’m staying patient and thinking positively about getting AV-1 here at Wallops.

On Thursday, August 28th, I was able to watch AV-6 take off from Wallops Flight Facility. The black plane that you can see in the linked video is flown as an added safety precaution as it follows the UAVs during take off to make sure no other aircraft crosses its path. The photo below shows what Cristobal looked like shortly after take off around 7 pm from the Geostationary Operational Environmental Satellite (GOES):

Slightly after AV-6 (green aircraft icon) took off from Wallops Flight Facility on August 28, 2014, Hurricane Cristobal was located just off the East coast of North America. This image is a combination of GOES visible imagery and a Google map for reference.

Slightly after AV-6 (green aircraft icon) took off from Wallops Flight Facility on August 28, 2014, Hurricane Cristobal was located just off the East coast of North America. This image is a combination of GOES visible imagery and a Google map for reference.

One of the challenges for mission scientists during this flight was that Cristobal was moving rapidly. Throughout the night, forecasters and scientists were altering the flight plans to account for the fast motion of the storm as well as commercial air traffic in the region, in order to get the best possible coverage of Cristobal. Overall, the flight was a success and the mission’s objectives were achieved.

While I was tracking AV-6 on the way home from Cristobal, I had fun looking at the imagery that was taken from a camera on the bottom of the aircraft. Below is a photo captured on the way home from Cristobal on August 29th:

Imagery from AV-6 on the way home from sampling Cristobal; Sunlight reflects off the Atlantic Ocean and clouds cast shadows onto the sea surface

Imagery from AV-6 on the way home from sampling Cristobal; Sunlight reflects off the Atlantic Ocean and clouds cast shadows onto the sea surface

After the excitement of Hurricane Cristobal, forecasters and scientists are looking for the next storm to target. The National Hurricane Center has given a tropical wave over the northwestern Caribbean a 60% chance of tropical cyclone formation over the next 5 days. This system will likely be AV-6’s next target in the Bay of Campeche on Tuesday, September 2nd. If you would like to follow along with the flight you can track AV-6 on this page.

Hurricane and Severe Storm Sentinel (HS3) 2014: Hurricane and Severe Storm Sentinel (HS3): the 2014 Season Begins

August 28th, 2014 by Mary Morris

Welcome to the HS3 blog! My name is Mary Morris and I am a graduate student studying atmospheric science at the University of Michigan. Over the next few weeks I will be posting about my experiences while I participate in the HS3 mission at NASA Wallops Flight Facility.

HS3 is a mission designed to investigate the processes that control hurricane formation and intensification. In order to collect observations of hurricanes we have two unmanned aerial vehicles (UAVs) outfitted with meteorological instruments that we can fly for long distances to reach hurricanes and storms forming in the Atlantic Ocean basin. On one of those UAVs, AV-1, is an instrument called the Hurricane Imaging Radiometer, or HIRad. My graduate research is currently focused on extracting surface wind speed and rain observations from HIRad data, so participating in the collection of HIRad data is an exciting opportunity. While the HIRad team has been here at Wallops since August 25th, we are still awaiting AV-1’s arrival. Until then, HS3 scientists will be relying solely on the other UAV, AV-6, to investigate hurricanes.

AV-6 arrives at the Wallops Flight Facility on August 27, 2014

AV-6 arrives at the Wallops Flight Facility on August 27, 2014

Wallops Flight Facility (WFF) welcomed AV-6 back from Armstrong Flight Research Center (AFRC) on August 27th. On the way to WFF, AV-6 was able to get a good set of observations of Hurricane Cristobal. In order to collect data on the storm’s environment, AV-6 uses three types of instruments. First, dropsondes are—you guessed it—dropped from AV-6 to gather information about air temperature, dewpoint, atmospheric pressure, and winds. Dropsondes are similar to weather balloons. The Scanning High-resolution Interferometer Sounder, or S-HIS, is used to gather information about air temperature and water vapor. And finally, the Cloud Physics Lidar, or CPL, is used to gather information about clouds and aerosols in the atmosphere. All of these observations are helpful for analyzing the environment of a hurricane.

Since the UAVs can fly long distances, we are going to get a good second look at Cristobal later tonight and tomorrow. HS3 scientists are particularly interested in observing Cristobal as it interacts with a frontal zone. As Cristobal interacts with the frontal zone, it will lose the characteristics that make it a tropical cyclone and gain characteristics that will make Cristobal an extratropical cyclone. In short, the differences between these two types of cyclones have to do with where the cyclones get their energy. With the NOAA Hurricane Hunters collecting data on Cristobal from the beginning, and with HS3 following up on Cristobal tonight, atmospheric scientists will have lots of observations that document Cristobal’s life cycle. These observations will then help scientists as they continue to research the processes that underlie hurricane formation and intensification.

Ship-Aircraft Bio-Optical Research (SABOR): Video “Games” for Science

August 19th, 2014 by Carlos Carrizo, The City College of New York

The R/V Endeavor returned from sea on Aug. 6, concluding the fieldwork component of the 2014 SABOR experiment.

As mentioned in the previous blog (“A Vast Ocean Teeming with Life”) ending this cruise is not an easy thing to do. Especially if you experienced the majesty of the crystalline blue water in the open ocean as well as the magnificence of the wildlife surrounding it for the very first time. I am currently coursing my third year as a PhD student in the Electrical Engineering Department of The City College of New York (CCNY). I work as a research assistant for a small department in the Optical Remote Sensing Lab called Coastal and Oceanic waters group. We may look like a group of cool guys going out for fishing (as it seems on the left side of the picture), however, we are a team who works hand to hand together (depicted on the right side of the picture … why does the right side always seem right?)

"Cool guys” aka Coastal and Oceanic waters group, members of the ORS Lab at The City College of New York (CCNY). Courtesy of Lynne Butler

“Cool guys” aka Coastal and Oceanic waters group, members of the ORS Lab at The City College of New York (CCNY). Courtesy of Lynne Butler

My research consists of using polarization properties developed as the light field propagates through the water body and use this information to characterize and retrieve water constituents and inherent optical properties (also called IOP’s) from polarimetric measurements. The basic idea is that as light propagates through the water it experiences significant attenuation due to absorption by water and suspended/dissolved matter as well as scattering by water and suspended particulates. These effects, both absorption and scattering, result in signal degradation of the radiance captured by sensors in our instruments. The additional information obtained when using polarization properties of underwater light propagation can provide a better understanding of this propagation and methods for improving image quality and increase underwater visibility … wait! (at this point you may be asking yourself).

So how can this have a real contribution to the goals and objectives pursuit by the SABOR (Ship-Aircraft Bio-Optical Research Campaign) cruise? Well, the answer could be very simple. The ocean is too big and in-situ measurements are too expensive to cover the entire water mass on Earth. Having this in mind, it is very clear that we need to adopt another cost-effective approach and that is the reason why we use satellite observations to account for many changes that take place in the ocean and coastal waters. Satellites provide very useful information when properly calibrated. As you may already know, sensors deteriorate over time and satellites go out of commission. However, polarization features are preserved even when the sensors may have experienced normal degradation and knowledge of this features can contribute in the development of future technologies to be used in satellites when more accurate and reliable information is to be acquired. Some living and manmade objects in water have partially polarized surfaces, whose properties can be advantageous in the context of target camouflage or, conversely, for easier detection. Such is the case for underwater polarimetric images taken to detect harmful algal blooms (red tides) or to assess the health of marine life and coral reefs which are of significant scientific and technical interest.

The main challenge faced by these images is that of improving (increasing) the visibility for ecosystems near and beyond the mesophotic depth zone. Data collected in the form of images, videos and radiance was acquired using a green-band full-Stokes polarimetric video camera and measurements of each Stokes vector components were collected as a function of the Sun’s azimuth angles. These measurements are then compared with satellite observations and model using a radiative transfer code for the atmosphere-ocean system combined with the simple imaging algorithm. The main purpose of this task is to validate satellite observations and develop algorithms that improve and correct these observations when needed.

But seriously… Are you playing video games? Courtesy of Lynne Butler and Ivona Cetinic

But seriously… Are you playing video games? Courtesy of Lynne Butler and Ivona Cetinic

It always looks like I am playing video games but in order to have very accurate information it is advisable to position the instrument at a certain orientation with respect to the Sun’s azimuth angle. The instrument depicted here is called Polarimeter and as Robert Foster suggested in his blog it has a very boring name, so we are still in search of a cool code name after someone suggested (unsuccessfully, and I am glad for this) to call this instrument Carlos. A real issue came across when they were thinking to put Carlos in the water … an idea that I didn’t share. The polarimeter, let’s forget about Carlos for a moment, is a set of Hyperspectral Radiance sensors with polarizers oriented in the vertical, horizontal and 45° from a reference axis. This sensors can capture light coming from any point in the water body thanks to a combination of a step motor which can be programed to stop in any sequence of angles in the range of 0 – 360° (from vertically up to vertically down) and a pair of thrusters (or propellers) which can rotate in the azimuthal direction (both clockwise and counter-clockwise). This scenario allows for vitually a 3-D range of hyperspectral measurements. Pretty cool, huh? The set of bouys at each corner allows us to have a very stable system and prevent the instrument from going very deep down in the case that cables and safety line get cut.

When things go like they do in the left image, we always have to do  the right thing. Courtesy of crew members and Ivona Cetinic

When things go like they do in the left image, we always have to do the right thing. Courtesy of crew members and Ivona Cetinic

Very far from what most of us have probably experienced in a cruise or fishing trip, the ocean is not always calm. In our twenty plus days in the ship, we came across a system which was playing very rough against the R/V Endeavor. Fortunately for us, this cruise was under the supervision of very talented and experienced people. I am not talking only about the captain, but also his outstanding crew members, chief scientist and marine technician. Although we have some minor difficulties (… you should know by now that sea water and electronics will never be good friends) we fixed them as soon as the storm was gone. It is not that Robert and I are playing as firefighters rescuing a dispaired kitten from a tall tree.

I want to end my vision of this field campaign with a summary of the awesome marine wildlife that somehow approach to us to say hello, some species more shy than others, to this group of scientists which were part of NASA-SABOR. As depicted in the picture (left-to-right and top-to-bottom), one of the first appearences was that of a seagull. It doesn’t look that shy since it preferred posing for us on top of the Polarimetric Lidar (owned and operated by scientist from NRL). Very intelligent creature this particular one, the others were just swimming in the waters and preparing to be a snack for a hungry shark as depicted in the image in the top center. Another interesting character which showed up near the surface was previously mentioned by Matthew Brown from Oregon State University in the previous blog post and it was a species of blueish salp with very long tentacles. The next creature is a very friendly dolphin which pretended racing us so we could take very amazing pictures. Dolphins always so adorable, appearing in pods and jumping out of the water around the research vessel or just posing underwater in front of the polarimeter! The last living character was a very shy sperm whale. Always keeping the distance but letting us know it was present leaping out of the water at most 300 feet from the ship!

Wildlife in action. Courtesy of crew members, Courtney Kearney and Ivona Cetinic

Wildlife in action. Courtesy of crew members, Courtney Kearney and Ivona Cetinic

These past three weeks in the R/V Endeavor had been very amazing although intense. Waking up and knowing that you are far from home, your friends and family may sound questionable but understanding that you are in front of one the most wonderful and powerful sources of life is a priceless experience not all of us can witness. That is why I am writting this blog and I hope you have enjoyed reading all our blogs and could have a taste of what is like being in the sea for three weeks!

Notes from the Field