08/10/02 - Sargassum overload & the "Franken-net"
After we sent last night's message, we continued to put out the Neuston Net over the side of the ship. The Neuston Net has floats across the top of a five-foot by eight-foot rectangular metal frame. Weights are attached to the bottom. The net tapers to an opening of about two feet in diameter. A Neuston Net is roughly 25 feet long and is designed to catch the materials that float along the surface of the sea.
A great variety of life is found around mats of sargassum. Over the past few days we have had empty nets, so last night we were excited to see sargassum floating on the surface. After sunset we started the Neuston Net, and it pulled through some mats of sargassum. Boy, did we get more than we expected! When the net came up, there was sargassum attached to the frame and the cabling , and the net was bulging. The net was so heavy that when we tried to lift it onto the boat, it started to tear. The more we struggled to get the frame and net on board, the bigger the holes became. We finally tied the frame to the boat and used an additional winch to raise the back end of the net onto the deck. We dumped the sargassum out and started to look through it. We found lots of interesting fish, crabs, and shrimp, but the quantity of sargassum was overwhelming! We measured 260 gallons of this material, which probably weighed about 4 pounds per gallon.
We would like to find out some equivalents to this incredible sargassum catch. What weighs the same amount as this haul? What takes up the same amount of space? Can you help us visualize this quantity of sargassum? Please respond by using the "Ask a Question" link on our Web site.
This morning , we arrived at the Lophelia Banks. The sea is still too rough to use the submersible, but we have put out the Otter Trawl. We could try to gather sargassum (if we really needed to!) because the holes in the Neuston Net were sewn up overnight. We now call this net "Franken-net" due to all its stitching.
One Otter Trawl came up with chunks of black plastic. We puzzled over what this might be until we realized that one of the floats along the top had imploded due to the water pressure at that depth. We have since replaced the plastic floats with metal floats! Some of todays catch data is posted from this trawl.
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