Posted by: Alison Cawood | August 11, 2009

SEAPLEX Day 10 Part 1

The SEAPLEX cruise is going well.  They are still in their intensive sampling phase, so everyone is tired, but other than that, they seem to be in good spirits.  They are having great weather today, with no ill effects from Tropical Storm Felicia.  They have seen a shark and some flying squid.

Our first post today is from Meg Rippy.  This is Meg’s second blog entry.

Meg writes:

Hello everyone. I thought I’d fill you all in on some of the truly awesome events that have occurred while filtering seawater for phytoplankton analysis on the night shift these past few days. For starters, the 3 a.m. CTD cast on August 5th brought up some bioluminescent organisms from 70 meters (about 230 feet) deep. Bioluminescent organisms produce flashes of light through chemical reactions involving enzymes from the luciferase family. These flashes are often blue in color and can be used to deter predators, find mates, or attract prey. The bioluminescent organisms we’ve collected may have been small phytoplankton because they were very small (only retained on filters with pore sizes of 8µm (0.000 3 inches) or less), and were found at the chlorophyll maximum (the water column depth with the highest concentrations of chlorophyll, the compound used by most phytoplankton and terrestrial plants for photosynthesis). Furthermore, it is likely that the bioluminescent organisms we found only produce luminescent displays when triggered by mechanical stimulation like predation or wave motion. The reason I say this is because I had no idea that there were bioluminescent organisms in the water I’d filtered until I folded the filters and wrapped them in tinfoil for pigment analysis. The act of folding the filters is what stimulated the phytoplankton on them to bioluminescence. The resulting flashes of blue were startling, and incredibly beautiful.

Our night time seawater filtering has also resulted in other really interesting finds. Just this morning I filtered some seawater from 210 meters (689 feet) deep and found what appears to be a small (~0.5mm or 0.02 inch) piece of blue-green plastic. This was a really exciting and yet horribly depressing find because it suggests that plastic can be present at depth in the ocean. There are several possible ways for plastic particles to get to depth. First, and perhaps most simply, it could sink. It could also be mixed down into the ocean by wind or other physical processes. Organisms that migrate from the surface to depth could also potentially transport plastics. At this point, however, we really don’t know which, if any, of these processes are important for the transport of plastics to depth in the gyre as it is difficult to say anything substantive from one plastic particle. It will be really interesting to see if any more plastic comes up in the CTD or in the bongo and mid-water trawls at later gyre stations.

Cheers to you all from the night shift,

Bongo-retrieve-8-8-09 (Large)SEAPLEX scientists retrieve the bongo nets after a tow in the North Pacific Gyre.

plasticbottles-8-10-09SEAPLEX researchers recover three plastic bottles covered with marine organisms, including large barnacles.



  1. what made you want to join, and be apart of this research.? brianna perez cvhs

    • I wanted to be part of it because it is an interesting environmental science question. People tend to forget that their actions influence the world around them. It is easier to look at human impacts in coastal areas or on land, but most people would never imagine that they could impact organisms in the middle of the ocean.

  2. Is it possible the plastic slowly sinks as the weight is increased by eggs and other organic matter?

    Those tiny plastic particles seem like they would be a nightmare for filter feeders. Do thouse usually pass through easily?

    • It is entirely possible that the organisms on the plastic will cause it to sink. Scientists have very little understanding of how the plastic is distributed with respect to depth, and this is one of the things that the SEAPLEX researchers are investigating. We also don’t know how the plastics impact filter feeders. Some work will be done after this cruise to examine the gut contents of the various organisms (of various feeding modes) in an attempt to tell if they are ingesting the plastics.


  3. According to, 70 percent of discarded plastic sinks to the bottom.

    In the North Sea, Dutch scientists have counted around 110 pieces of litter for every square kilometer of the sea floor, a staggering 600,000 tonnes in the North Sea alone.

    These plastics can smother the sea bottom and kill the marine life which is found there. With so many threats to the world oceans including pollution like the plastic getting stuck in this huge trash vortex, overfishing and climate change we urgently need to rescue marine biodiversity in the most effective way possible.

  4. Wow so that means you guys are following up on things even in the night thats did u find the phytoplankton if there extremley tiny is there this special equipment u use.if so what do u use to look and observe it?Also if there is much more plastics at the depth of the water what can the outcome of that be?

    • The phytoplankton are everywhere in the water! If you have ever been in the ocean, I bet that you have swallowed thousands of them. They are single cells, but some of them are large enough to be seen with the naked eye. We also use particle counters and microscopy to count the cells and to figure out what kind they are. We don’t know how much plastic there is deeper in the water column. If there is a high concentration, it could be eaten and moved around by the animals that live there. If it is at depth, there is also a greater chance that it is making it to the sea floor where it will impact that community.


  5. […] Weblogs Wetenschap The Great Garbage Patch onderzocht04-09-2009 om 13:29 door Carlos Op deze (plastic) flessen die in de Grote Oceaan dreven hebben zich zeepokken vastgezet. Afgelopen maand deed de Seaplex […]



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