Merry Mud Making

Had lots fun on Friday collecting lots of sediment samples for Dave Hawkins' thesis.  It was warm most of the day until the sun got low...then we sang some carols to keep us warm.  It was great to get out on the water.

Holiday Grab Sampling

Got to do some fieldwork on Croatan and Pamlico sounds today.  It was a bit chilly but nice on the steel blue and cold, quiet water. And it was another scenic sunset from the UNC CSI.

Our First Boat Trip from the New UNC CSI Campus

How else would we enjoy our spring break!?

With a nice, sunny and, most importantly, low-wind-speed day, Reide and I decided to head into the Albemarle Sound to check on the state of some equipment and recover a deployed acoustic bat sensor. Our new post-doc Brad Pickens came along on the adventure.

Although a cool ride out, the seas were calm and the trip was fast! We found our equipment to be in good shape (despite a little guano). Reide disconnected the bat monitoring equipment, and we all worked to get it safely aboard our vessel. Then, J.P. donned a thick wet suit and braved the cold water in the effort to recover a water quality monitor deployed last year. Unfortunately, he was unsuccessful in locating the device without scuba equipment.

Nevertheless, it was a productive and fun trip, and it was awesome to finally have our first boat trip from the new UNC CSI campus!

J.P.

All good things...

Again, it has been too long since I last posted.  We have continued to be very busy in the field and laboratory, trying to collect as much data before the end of our time here.  Speaking of that…today was our last day in the field…so all samples have been collected for this field season.

 

I wanted to highlight a couple things that we have done since I last posted.  One of the exciting finds was a "river" of water coming out from the bottom of the Marr Glacier in the backyard behind Palmer Station.  It was flowing at a fairly high rate for several days.  The water was literally pouring out of the glacier and cascading down the rock face, cascading into the surface water.  We sampled the water directly from the glacier and as it fell into the surface water.  This is essentially one of the end-members we are trying to quantify entering the coastal ocean in this area. We were really excited to have the opportunity to get samples directly from this freshwater source as it entered the ocean.

 

As we were sampling, the glacier several hundred meters from us began to calve in several places.  I was able to catch a few of the events on camera, although a video would have been better.  You can see a large chunk of ice falling from the glacier in the center of the picture.  Incredible to watch these events occur…the amount of ice entering the ocean through these calving events is pretty impressive.  We have watched these events occur throughout our stay here.  The most impressive event occurred during our last time-series event…an extremely large calving created a 6-foot wave that hit the shoreline that we were working on.  Amazing, but no pictures…we were too busy trying to protect our equipment!

 

Finally, I was lucky enough top be a part of a live broadcast into several classrooms in Northeast NC.  David Sybert and John McCord (both at UNC CSI) arranged the broadcast and did a great job putting everything together.  You can watch it here…

 

http://www.ustream.tv/channel/unc-coastal-studies-institute

 

It was a really cool experience and I hope you have some time to check it out.

 

We start cleaning up all our gear and packing everything away tomorrow.  We will board the RV Gould on Sunday and start our trek home.  I am looking forward to getting back home…excited by all that I have experienced since arriving in Antarctica!

Following the Tide

Science has continued and a fast pace since I last wrote.  We only have a bout 1.5 weeks left to complete our fieldwork, but I think we are on track to complete most of the tasks we came down to do.

 

One of those tasks was to try and evaluate how groundwater discharge along the coast changes with tides.  The plan...we want to measure all the chemical tracers (mentioned in earlier blogs) in the surface water and groundwater every two hours over a 36 hour time period, while imaging the subsurface using resistivity.

 

Lets start with the tide…crazy thing down here.  The tides change from diurnal (1 high tide and 1 low tide in a lunar day, 24 hours and 50n minutes) to semi-diurnal (2 high tides and 2 low tides in a lunar day)…within the same month…not many places switch between the two cycles.  As the tide changes, so does the interaction of the surface water and groundwaters.  As the tide rises, surface water tends to move into the sediments.  In contrast, as the tide drops, groundwater is more likely to discharge into surface water.  This back and forth movement of the water is often referred to as tidal pumping.   We wanted to evaluate whether this process was occurring here and the possible changes in water chemistry during the process.

 

So, the site we chose is one of the few areas around here that actually has a sandy beach.  Most of the coast is very rocky.  This area was recently exposed due to the retreating glacier, so it offers a great opportunity to study a type of landform that is likely to be exposed more and more as the glaciers continue to retreat.  The area is know as Point 8 around here, named by the Navy during early surveys of the area (see the first picture, setting up the site).

 

Again, we collected surface water directly with a pump and groundwater using a drive point sampler (a pvc pipe we worked into the sediment about 30 cm). From these we can evaluate changes in the tracers and nutrients as the tide changes.   We also measured the resistivity of the subsurface.  This is a method that allows us to evaluate the difference between saltwater and freshwater  beneath the ground.  Doing this over the course of the tidal cycle provides direct evidence of subsurface mixing and discharge of water.  Included is a single image of one of the resistivity measurements.  The light blue colors are saltier water and the warm colors are fresher water.  The left side of the image in the water…the last 6 meters of the cable is submerged.  The right side of the image (when this was collected) is not submerged at all.  Again, just to give you a sense of the sort of data we are reviewing to provide information of the subsurface.

 

Time-series work can be quite exhausting.  Our crew was awake for about 48 hours when it was all said and done, preparing, running experiments, breaking down and cleaning up.  But the data looks really great.  Being out on the "ice" and away from station for that long was also quite interesting.  The glacier was calving (large ice chunks breaking off) all around us.  On large calving event actually created a small local tsunami about 7 ft high.  Impressive in its power…creating havoc on some of our equipment.  Also, there were times when we had to deal with the locals…penguins and seals.  That was exciting at times as well.  But, some of the images that mother nature provided us are better than any data we could have ever collected.  The last image is a picture I took at about 5am.  The sky never gets dark, but this is equivalent to a sunrise over the glacier…magnificent.

 

What a great experience…all around!