Monday, June 18, 2012

Who's Who: Stephanie Nebel

Steph is in her third year as a PhD candidate of Geology at the University of Delaware. She is at the tail end of her project, currently writing the analyses and eventual conclusions of her dissertation.


Steph's dissertation is a continuation of her masters thesis, which was also conducted through UD. As a graduate student, she investigated the retreat rates and shoreline movement of Cedar Island, a barrier island in Virginia near the Delmarva Peninsula. By means of varying sediment supply, sea level rise, and storms, Cedar Island is retreating landward at rates much higher than other barrier islands on the eastern coast. Steph determined how quickly the island is retreating and the variation of this rate over time using topographic maps, satellite images, GPS data, and other sources. Recently (1994-2007), Cedar Island has retreated at a rate of -12 m/yr! She was also able to compare the historical retreat rates with the Atlantic hurricane record and find that an increase in storm frequency correlated with an increase in island erosion.  


Now, her dissertation work looks at a different, less historical aspect of Cedar Island's trend of retreat. Instead of focusing only on the surficial features of the barrier island, she took a closer look at the features on and beneath the ocean floor to determine the preservation potential of its associated inlets. The instrumentation used took data that extended to as much as 60 meters below the seafloor. As Cedar Island migrates, its inlets should as well, in theory. Using seismic profiling and sidescan sonar, two surveys were completed in 2009 and 2010. The data was analyzed and visualized in SonarWiz. Steph is currently looking within the seismic records for an upwards "U", channel-like features that indicate old, previously filled inlets. If the inlets were not preserved, they would have eroded away and not appear in the seismic profiles at all. Once she finishes evaluating the seismic material, she will move on to the data taken with the sidescan sonar.


Steph enjoys studying Cedar Island and the surrounding areas in Virginia because they remain mostly uninhabited by people. Therefore, the trends observed are virtually free of human influence- a breath of fresh air on a coastline where beach tourism is prevalent.

Additionally, Steph had the opportunity to spend two and a half weeks on the Ocean Exploration Trust's E/V Nautilus in 2010. As a data logger, her role was to monitor data as it came in. She will be returning to the Nautilus this August to train as a data manager.

Who's Who: Justin Walker

Justin Walker is a second-year masters student in Geology at the University of Delaware. He is currently at work processing data from his masters thesis project, an investigation into scallop distribution and size in the Mid-Atlantic Bight. The purposes of his project are to determine scallop distribution in this region and develop a new method of assessing this economically important marine organism. This small-scale stock assessment utilized an AUV to capture almost 254,000 images of the Atlantic seafloor. This collection technique replaced more common methods such as dredging, which are significantly detrimental to the ocean floor and its inhabitants. The images taken by the AUV were later analyzed and Justin is now working to process and visualize the scallop data.


Over 27 three hour missions on the F/V Christian and Alexa last summer, Justin and his research team took roughly 14,000 scallop-containing photographs with the AUV, amounting to approximately 18,000 scallops. Each image was 1.7m x 1.3m in span and was taken about two meters above the seafloor. Naturally, analyzing the images could not be efficiently completed by hand. Justin therefore used a custom computer program to count and size the scallops in each of the photos taken. The size of the scallops also amounts to its age. The shells of scallops, like trees, accumulate one ring each year of existence. A team of four, including Justin and three interns, completed the scallop counting.


Much of the statistical analysis that Justin is performing now is to observe the distribution of the scallops. Do scallop populations patch, or are they evenly distributed? Are more scallops likely to be found where other scallops reside? Justin hopes to answer these and other inquiries in the conclusions of his thesis. He notes that the scallops seem to follow a random distribution pattern based on the preliminary results. Using software like ArcMap and MatLab, the data was visualized in the form of various charts and images.


Additionally, Justin's project was extended to make comparisons between his scallop data and the data collected by the National Marine Fisheries Service (NMFS). As previously mentioned, dredging is the primary method for making annual stock assessments of scallop populations. In the areas of the Bight where NMFS had previously dredged, Justin deployed the AUV in the same transects. This was possible due to the dredge scars that are visible on the seafloor for sometimes several weeks after the initial data collection. By comparing amount of scallops photographed by the AUV by the scallops collected by the dredge, the efficiency of the dredge could be calculated. As one might assume, dredges are not completely efficient, as scallops can escape detainment. The AUV is assumed to be almost completely efficient unless the water is particularly cloudy or the camera lens is inhibited in some way. As expected, the dredge collections were about 55-60% less efficient than the photographic collections.


Justin is hard at work on his master's thesis, and we are all excited to see how his project culminates!

Who's Who: Carter DuVal

Carter DuVal is beginning his first year as a University of Delaware masters student of Oceanography. With an undergraduate degree in Archeology from St. Mary's College of California, Carter now hopes to hone in on his personal interest, underwater archeology, during his time as a graduate student and beyond.


As a prospective student, he assisted with the data collection for Justin Walker's masters thesis, which focused on the density and distribution of scallops in the Mid-Atlantic Bight, mentioned in an earlier entry. Shortly after, he spent 21 days on the Ocean Exploration Trust's E/V Nautilus as a navigator.


His masters thesis will focus on the sand ripples around Redbird Reef, an artificial reef 16 miles east of the Indian River Inlet in Delaware. This reef is made up of New York City "Redbird" subway cars, barges, tugs, and similar objects submerged from 1997 to 2010. These recycled cars and vessels make ideal materials for artificial reefs, as their structural cavities create a desirable environment for reef fish. Though the methodological specifics of the project are not yet complete, most of the principle aims have already been laid out. He hopes to investigate how associative currents and conditions affect the formation of sand ripples in Redbird reef, therefore analyzing the effect of the artificial objects on the adjacent geological environment.


A combination of a rotary sonar and an Acoustic Current Doppler Profiler (ACDP) will be the primary means of remote sensing. The sonar will take a 360-degree view of the sediment around the reef, and the ACDP will measure absolute current velocities. Data collection will occur for several months so that variation over time can be observed. A unique point of Carter's thesis is that he will be utilizing a fingerprint algorithm to process the sand ripple data. The algorithm was initially used to study ridges in fingerprints, but has recently been used by a UD doctoral student for the purpose of underwater geology. This analysis tool recognizes ripples in the ocean floor and yields orientation, wavelength, and spatial density.


Carter is excited to begin his research and combine his two interests of archeology and oceanography. With a first deployment date of approximately two months from now, much preparation is underway. 

Saturday, June 16, 2012

NEEMO 16- finale intern entry by Kaila Cappello

After the late night we had Wednesday, we were fortunately allowed to sleep in on Thursday and had our science team meeting at 1 pm. We discussed plans for the Deepworker dives to take place and planned our departure for the Lana Rose to be at 2 pm. This time, I went alone to the ship as the only one who knew how to deploy the Castaway and Sonde, and I was a little nervous that I might mess something up without help. When we got to the Lana Rose, I quickly hopped aboard and got the equipment ready before handing it off to the NUYTCO crew to mount them onto the subs and returning to the dock on the Latency.

                  When I returned to the science trailer, we waited around for a little while until the subs were to be deployed around 5 pm. When the dive started, we again  took notes as we saw targets of interest, and we scored the data and observation quality of the live feed we saw from Deepworker 6. About an hour into the flight, we lost connection with the sub and could no longer see or hear what was going on. An issue with the tether that kept us connected was identified, and the dive continued but without us being able to see anything. Since there was no more need for our support during the dive, we cleaned up the trailer a bit before heading to Sharkies for the night, a local bar and restaurant that draws a very unique motley of locals and tourists.

                  The next day we met at one of the condos of the Port Largo Villas to go over all of the video data of the dives. Similarly to what we did during the flights, we went over at least seven interesting parts of each flight video and scored the data and observation quality, as well as the science merit, and we assessed how much of each planned flight was completed.

                  After we finished up, we went over to the science trailer to gather and pack up all of the equipment and belongings that we brought and packed and labeled some sediment samples collected during one of the flights. After we got everything together, we relocated to the pool area for a barbecue for the science team and others involved in NEEMO 16. Afterwards, I was lucky enough to take part in an informal presentation by Dr. Paul Abell of NASA about the very real threat of asteroids and the importance in studying them and potentially traveling to one in the future. Listening to him speak made me incredibly envious of what he does for NASA and his incredible knowledge of space.

                  My week working with NASA unfortunately has come to an end, and I am unbelievably thankful that I got to be a part of this mission and be in the presence of such extraordinary people. I am both extremely thankful and jealous of the work that NASA, NOAA, and all of the other organizations and people involved in NEEMO do, and I hope that some of our paths will cross again in the future.

Saturday, June 9, 2012

The Transit of Venus and the Distance to the Sun | Wired Science |

Really cool step by step on an analysis of the recent transit of Venus. Bet Captain Cook wished he had that when he made his voyage.

Macworld How I name files on my Mac | Operating Systems | Working Mac

Interesting read. Dates in the file name I totally agree with and some meaningful description but I don't agree with using blank spaces and I prefer underscores to hyphens.

Dr. Art Trembanis
Associate Professor
109 Penny Hall
Department of Geological Sciences
The College of Earth, Ocean, and Environment
University of Delaware
Newark DE 19716
"We shall not cease from exploration. And the end of all our exploring will be to arrive where we started and know the place for the first time."
-T. S. Eliot, Little Gidding

"Il faut aller voir" -JYC

Exploring the oceans: 20,000 colleagues under the sea | The Economist

Love the lead picture that accompanies this article but where are all the other propeller type AUVs??

Friday, June 8, 2012

Cape Henlopen Shipwreck X -by Danielle Ferraro

On June 4th, 2012, a survey team conducted a side-scan sonar and ROV investigation of an unknown shipwreck off Cape Henlopen in Lewes, Delaware. The team consisted of CHSEL lab director Dr. Art Trembanis, ROV surveyor Jeff Snyder, state archeologist Craig Lukezic, graduate students Trevor Metz and Carter DuVal, and undergraduate intern Danielle Ferraro. This was the first time the wreck had been investigated in depth since its discovery in 2010. 

Using an EdgeTech 4125 600/1600 side-scan sonar, we were able to make several passes over the shipwreck site. Amazingly, the wreck was only 175 meters from the Lewes shoreline and five meters submerged. While it seems unlikely that the wreck had not been previously detected, it may have been covered in sediment and eventually exposed by strong wind-driven currents during a relatively recent storm.


Once we captured strong sonar data of the wreck, our research vessel was anchored and the VideoRay ROV was prepared for deployment. (Watch the deployment of the ROV here.) The ROV had a BlueView 900 130° multibeam bathymetry sonar as well as a video capture. The BlueView sonar enabled Jeff to establish a proper heading and provided us with a better look at the entirety of the wreck. It seemed that the ship had suffered damage in the presumed bow section. On the presumed stern side, some ribbing, a mast beam, and possibly a hatch may have still been intact, though no definite identification of features have been made thus far through the multibeam returns. The video taken by the ROV was streamed onto a topside computer for real time viewing. Much of the wreck was encrusted with mussels, and other invertebrates such as anemones colonized some sides. 


As the day progressed, the winds increased and caused the currents to pick up. It was increasingly difficult to control the ROV's movements in the turbulent shallow water. Despite this, much was learned about this unknown shipwreck. It seems likely that the ship was steel or iron, due to the hard sonar returns and large amount of wreck that was still structurally intact. Given the amount of time the ship was submerged based on the magnitude of invertebrate colonization, a wooden ship would have mostly deteriorated by this point. We will investigate further to try to identify the wreck by comparing our findings to state and local records. Stay tuned!