Closed Saltwater Ecosphere: Caribbean Ecosystem in a Jar

[00:00:12]Hello there. Today we're looking at this jar. To  make it a bit more exciting we'll actually fill it. But what happened in between, and why? Well,  for my master's degree I was following a course on the southern Caribbean island of Curacao -  shout out to all my Caribbean viewers. I knew I had to make an ecosphere from the ecosystem I saw  underwater and so I did, minus the corals and fish and all large organisms of course. I was there for  quite a while but I wanted to collect my materials at the latest possible moment, right before flying  back, not letting it all sit in the heat for days.

[00:00:52]This meant I had to collect it while snorkeling  and unfortunately I do not have any footage of that. I have these clips of me and some friends  collecting some sand and putting it in bottles.

[00:01:03]It'll have to do I guess. This is what I took with  me in the plane. Of course you cannot take this with you without the proper permits, so I did get  the proper permits. Customs was not amused though, and they took all the bottles and the jar and  went into their little room for 20 minutes or so, probably shaking it up a bit and sticking who  knows what in there to test for dissolved - um... forbidden substances - or something, I don't  know... Eventually I got it back though. Right, assembly time. In this jar. I attempted  to film this, and I guess succeeded, except that you can't see it very well.  I decided to shake the bottles to get the sand out as well. Normally I wouldn't shake  them this violently but I figured I couldn't really do more harm to the contents than had  already been done by their unexpected journey.

[00:02:10]I sorted all the water and rubble, a.k.a. rocks  with stuff on them, in two buckets. One that smelled okay, to be used for the ecosystem, and  one that smelled really bad, to be thrown away.

[00:02:24]Look, here we have a piece of rubble with a large  single-selled algae on it. A Caulerpa serrulata.

[00:02:31]Pretty neat. In the end I didn't throw the smelly  stuff away but chucked it all in a smaller jar, to see what would happen if you make a closed  ecosystem with mostly dead and rotten materials.

[00:02:45]So that's both of our Caribbean jars filled.  They're more cloudy than saltwater jars usually are, and I'm afraid that might be a sign that  there's already quite some dead material in there, but we'll just have to wait and see. I can't  really bring it all back... The Caulerpa is getting buried in sediment so I'll have to  gently shake everything clean when the dust settles. A day later the jars cleared up pretty  nicely, but were still a bit hazy. This algae is called Dictyota. It's easily recognizable by the  Y-shaped tips. Unfortunately it doesn't look like it's in great shape. We do have some animal life  in here. Here we have some kind of crustacean, it kind of looks like a tiny lobster. On the right  side of the screen you can see a copepod swimming up. Here's a better angle. I wonder if it'll stay  this small or if we can see it grow. A week later the water is still a bit hazy, which is slightly  concerning, but let's see what we have in this jar after a week. You can see some of the algae  growing on the rock in the center of the jar as well as on the foreground. More interestingly, and  weirdly, though is this this yellowish brownish slimy organism. I've tried figuring out what  it is, I really have, but I don't have a clue at all. I'm not even sure if it's an animal, or a  fungus, or a protist, or something else entirely.

[00:04:24]It reminded me somewhat of terrestrial slime  molds so I thought it just might be a marine slime mold. But I found no marine slime molds  that look similar. That doesn't rule out this possibility of course. Maybe it's some sort of  strange colonial animal, or a fungus. I really have no clue. I've never seen it move but I  think it moves very slowly. I've seen it a few times on different locations on the glass and  in different shapes. Maybe there's more than one, or maybe it can split up into several beings. It's  interesting that such creatures appear when you take some water and let it sit for a while. I of  course looked at the water and sediment closely while I was there - even in jars - and a bunch of  tiny critters became visible that you wouldn't see otherwise, but this organism I never saw there  and I've studied the underwater world carefully, and for quite a length of time. Fascinating. This  is a bit of a sad sight: a big old dead worm. This one most likely died during the trip already.  I tried to wash out all the dead material while putting this jar together but due to the geometry  of the rocks I probably missed some. I hope this much decaying organic matter won't cause too  many problems for the ecosystem. Here, next to another dead worm, we have the Caulerpa. Did  I already mention that the entire thing is only one cell? How cool is that?! It's still looking  okay and I really hope it survives, because it's the only algae and primary producer for this  ecosystem that still looks somewhat healthy, and something has to provide oxygen. Luckily not  all is doom and gloom for the worm population, and luckily I didn't wash too hard, because  there, in between the rocks, you can indeed see a worm moving about. And it is not alone. Under  this piece of Dictyota you can see another worm, quite a large one. At least I'm pretty sure it's  one individual and not two smaller ones. This, just like the other one and the dead ones, is  a Polychaete, commonly known as a bristle worm.

[00:06:40]There are many many Polychaetes, and getting to  the species level would for me be, at this point, just pointless guessing. But I do think they're  probably in the subclass of Aciculata. The more you know... This is the other jar, the one  I filled with the smelly and dead stuff, and what do you know, it looks way worse. There  seems to be this sort of dark tint to the water.

[00:07:08]There's a black residue, both on the substrate  and all the pieces of rubble. The black color in the upper part of the sediment is probably  the result of sulfate reducing bacteria, which, as the name suggests, reduce sulfate to hydrogen  sulfide. This hydrogen sulfide reacts with metal ions forming metal sulfides, which are insoluble  - insol - insoluble - creating the dark color.

[00:07:36]There, a bit of biochemistry to brighten up your  day! There's more going on though. Near the top of the water surface we have these slimy gelatinous  blobs, which have the same dark tint as the water.

[00:07:51]I don't actually know what it is, but I'm assuming  it has something to do with the large amount of dead material in the jar. Maybe it's some sort of  protein buildup, or a bofilm in an unusual shape.

[00:08:04]It could also be some sort of fungal growth.  It's actually kind of pretty in a way. I've never seen anything like it though. This smaller  jar is also home to this alien looking life form, which I think is actually the same organism we  saw in the bigger jar, just a bit more compact, and looking less like pulled apart molten cheese.  This one looks like one elongated blob with some threads coming out of the top. I feel like if you  know what this is, it's very obvious, but I don't, so... Now this is interesting. Sorry for the  shaky footage by the way. Here we have a boomerang looking shape with something looking like a  lightning bolt coming out of it. I'm not totally sure but I think the boomerang is a small ribbon  worm, and sticking out of it is its proboscis.

[00:08:59]The proboscis is an organ it uses for hunting,  which can be fully inside or outside the body, and sometimes even contain a toxic barb. Pretty  cool. Two weeks later, apart from some algae growing on the glass, I noticed something.  That one creature has split up, or multiplied, or more of them were showing themselves. Anyway,  now there's a few of them. I have all this footage of these weird alien looking life forms, but  since I don't know what they are, and there's only so many ways I can convey that fact, I've  run out of intelligent things to say about these.

[00:09:39]But they're really strange huh? Please someone  help me out here. Unfortunately at this point the Caulerpa isn't looking so great. If it dies,  the burden of producing food and oxygen will fall on the single-selled algae that are present in  this jar. So that is the Caribbean ecosphere, or ecospheres really. This project didn't exactly  go as I had planned, with some cool algae and a bunch of tiny interesting crustaceans comprising  the stars of the ecosystem. Unfortunately a lot of the material didn't survive the journey. I  guess being shaken around, going from 30° C to just a few degrees above freezing, high in the  air, and arriving in the Dutch winter climate, while being inspected by customs, is not ideal.  Nonetheless, every jar is interesting in its own right, and there is no shortage of fascinating  stuff going on in these jars. Together we will follow the events happening in this jar.  That's it for now, thanks and bye-bye!