Betsy Petrick: Shipwreck! June 29, 2019


NOAA Teacher at Sea

Betsy Petrick

Aboard R/V Point Sur

June 24 – July 3, 2019

Mission: Microbial Stowaways: Exploring Shipwreck Microbiomes in the deep Gulf of Mexico

Geographic Area: Gulf of Mexico

Date: June 29 , 2019

Science Log

I sat with the marine archaeologists and chief scientist and the operators of the ROV in a control room bolted to the back deck of the Point Sur.  Inside were at least 12 video monitors showing views from the ROV in color and infra-red, a sonar scanner, various mapping tools to track the location of the ROV and the ship, and controls for all the equipment on the ROV including cameras, lights, the sampling tray and robotic arms.  For a while we stared at the silty sea floor seeing nothing more than a few shrimp and rockfish and sea cucumbers. Every once in a while the ROV would kick up a cloud of silt and we would watch it swirl across the screen looking much like images of the cosmos.  

sonar of shipwreck
A sonar image shows the shape of the shipwreck on the seafloor. The sonar helps guide the ROV over the ship at a safe operating distance.

Suddenly a ghostly vertical shape appeared ahead, covered in part by a white lacey growth.  The closer we moved the more clear it became – this was the bow of the shipwreck we were looking for!  It stood out on the seafloor like a lone bedraggled sentinel in a watery desert. The ROV hovered around it.  We could see white branching coral called Lophilia, anemones, a long-legged Arrow crab and other species of marine life.  The ROV moved along what we thought was the length of the shipwreck. An anchor lay on its side with one hooked arm lifted and around it we began to see other things: white ceramic plates, a ceramic whiskey jug, some metal rods with a loop on one end that most likely came from the rigging.  

Bow of the Ship
This is the bow of the ship. All that is left is a large beam sticking up off the seafloor. It is covered in life.

The ROV passed over and around the artifacts, trying to see them closely, but at the same time we could not pick up or even move the silt away to see what else lay buried there.  With each new pass over the wreck more things were seen: a copper bell, some ceramic cups with blue decoration. We were not treasure seekers out to plunder. A good archaeologist doesn’t take artifacts out of context without good reason and permission.  Melanie Damour, the marine archaeologist for the expedition likens a shipwreck to a crime scene. Each clue tells the investigator a part of the story of what happened. If a clue is taken away, it becomes harder to piece the story together. Our expedition is to map and photograph the wreck, so we won’t disturb anything we see.  

Fish in and around artifacts
Fish make their home around the anchor of the shipwreck and other artifacts

Finally, the controlled mapping of the shipwreck began.  This is called photogrammetry. The plan was to do three passes lengthwise ten meters apart, and then repeated transects across the whole ship.  From these combined overlapping images, the archaeologists will make a 3-D map of the wreck. Hours later, mapping complete, the ROV returned to the ship.

Personal Log

By evening, a squall had found us, rain fell for a short while, the wind whipped the waves up, the ship pitched and rolled in an uncomfortable way, and to say the least, I lost my newfound sea legs and my cookies.  You don’t want to know the rest. 

waterspout
Every day there are amazing things to see. Here a waterspout has formed between a storm cloud and the sea.


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