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SEA Currents Blog

SEA Currents: Corwith Cramer

April 09, 2019

A small boat sailed to the big mat of Sargassum

Jane Sheng, University of Washington


Above: Cecilia and Jane in the small boat, sampling a Sargassum mat. Below: SSV Corwith Cramer, alongside Sargassum mat, photo taken from the small boat.

Current Position
South Sargasso Sea

Course & Speed
110° at 4.6 knots

Sail Plan
a single-reefed Mains’l, Main Stays’l and Forestays’l

Wind SxE, Force 3, Sunny, Light scattered cloud coverage, cumulus, altostratus

Souls on board

Today we decided to approach another big mat of Sargassum and take some samples from it using our small boat. Mats of Sargassum are very rare to see.  For example, our Captain Jason has sailed this cruise track north six times while it’s the first time to really encounter such large mats of Sargassum with such consistency.

I proposed to jump on that small boat because I knew it would be a very rare and exciting experience, and it was truly of huge fun from start to the end! Getting on a small inflated boat can be scary at first, but it turned to be so exciting as it started to move fast in the waves. Our driver Grayson seemed to be so proficient in steering the small motor-driven boat. I enjoyed the excitement you might get from an amusement park during our way to the big mat, and in a minute we arrived there. We could tell that most of the Sargassum mat was made of Sargassum natans I, one of several unique morphological forms of Sargassum found throughout the Sargasso Sea and Tropical Atlantic.

Cecilia and I collected samples from the big mat. We will later examine genetic differences of Sargassum forms, including the dominant form of this special aggregation. In this Sargassum mat, we also sampled an endemic shrimp, Latreutes fucorm, which inhabits pelagic Sargassum. This shrimp has been shown to be susceptible to an isopod parasite which burrows beneath the shrimp’s carapace, and is clearly visible as a large lump in its shell.  During the processing of Sargassum later I found the rate of parasitism of the shrimp living in that mats appeared to be relatively high: 11 parasitized shrimp out of 51 shrimp in total. Encountering a mat of Sargassum provides a special set of data for our research projects.

It’s also sad to mention that we found a fair amount of plastic debris in this aggregation of Sargassum. For example, Cecilia picked put a big chunk of plastic that might be a part of a bucket, and we picked up a single-used spoon. Oh, I hate single-used utensils, and all the plastic trash that ends up into the ocean. I was also reminded of a video I saw about a sea turtle getting a part of straw in its nose; the miserable mourning it made when the straw was taken out was just heart-breaking. The plastic aggregating in the ocean is not just a legend.

We are glad that we took some great photos from the boat. Gabe, our MBC lab hand, took several good photos of the Cramer—she was incredibly small in the giant ocean. It’s crazy to think that over 30 people are living aboard the Cramer for one month, performing daily activities and science. I also took a photo of Gabe smiling with the big mat of Sargassum and Cramer behind him. As lab hand, Gabe is helping to collect Sargassum-associated mobile fauna while wielding a heavy dip net every day.

Though we are accompanied by the amazing views of the ocean, the sky and clouds, and sunrise and sunset through the journey, today is definitely a memorable day.

- Jane Sheng, University of Washington

Categories: Corwith Cramer,Marine Biodiversity & Conservation, • Topics: c285  study abroad  research • (3) Comments
Previous entry: A Squally Day    Next entry: First part soon to be over


#1. Posted by Michele Ahlman on April 12, 2019

Wow! How exciting! Hearing about the discovery of plastics is disturbing. Although we hear about the amount of plastic that finds its way into our oceans, I’m sure it is quite upsetting to see it for yourself.

Hi Sam! Can’t wait to read your blog post!!

#2. Posted by Amy Stephan on April 13, 2019

What a fantastic experience!  As I stared at your location squarely in the middle of the Atlantic, my landlubber brain unable to fathom the nothingness in which you must be immersed, there it was… a detailed connection to the ecosystem and your scientific attention and wonder. Thank you Jane!  Also thank you for placing Gabe in that post. Knowing him, he must have been having the time of his life, and imagining him with that shot of excitement and wonder made me extra happy.  Hope all of you are taking a ton of pictures of those creatures, their various bumps and creating strong useful proof of the scourge of plastics in our seas. 

Any chance you can say what day specifically will be your arrival in Bermuda?
Or in NYC? 

I will check back here for an answer.  Fair winds! Love you, Gabe!

#3. Posted by HAONAN PENG on April 17, 2019

Really an amazing trip! Much more exciting than coding every day! (o_o) Almost considering changing major haha!



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