Blog post by Jean-Olivier Irisson
Blog post by Jean-Olivier Irisson
Hey plankton hunters! We are bringing you another round of Fantastic Finds from the Plankton Portal. Citizen scientists continue to reel in new captures of some truly awesome plankton. Here are just a few neat finds, ID’s, and novel taxa:
Did you ever learn about marine butterflies in grade-school? Well good, because there is no such thing as a marine butterfly. This elegant-looking critter is a pteropod, a type of gastropod mollusk—in other words, a slug! These mollusks are highly adapted for life in the water-column, as you can see from the butterfly-like wings, (or “parapodia” to a malacologist). The pteropod wings are actually a highly-modified molluskan foot, i.e. the muscular and slime-secreting mass that slugs glide on. Evolution really did these slugs a favor, as I do not think anyone could say “ewww!” to such a beautiful animal.
Now this is a fantastic image. A close-up, finely-detailed capture of the head (nectosome) portion of a calycophoran siphonophore—so aptly referred to as a “rocket-ship sipho” here on the Plankton Portal. The two siphon-like features propelling this colonial critter are very apparent in this image. Maybe, in truth, siphon-ophore is a pretty apt name for this plankter as well.
Ctenophore: Thalassocalyce inconstans
Thalassocalyce inconstans is a predatory species of ctenophore, captured feeding in this frame. The body of the ctenophore is contracted and engorged about the anteroposterior (vertical) axis, giving it the appearance of an inflated, heart-shaped balloon. Within the fragile and transparent body, you can see the 8 condensed comb rows captured as an array of ragged segments crowning the aboral end. Fine mesenterial canals also appear as contoured markings that line the engorged body. Ctenophores are tactile predators, meaning all predatory behavior is triggered by physical, non-visual stimulus. Something in the water column bumped into this Thalasso and got it all riled up, providing ISIIS a great opportunity for this detailed capture of foraging behavior. If we had a hydrophone for this deployment, I am fairly certain a satisfied lip-smacking would be recorded in a few seconds.
Copepods: Families Eucalanidae and Metridinidae.
Copepods are abundant in these ISIIS data, and it is easy to forget what a broad diversity of these important crustaceans are classified on the site. Here we have two broadly identifiable PP copepods for sample. The image on the left shows a copepod belonging to the family Eucalinidae: it has a narrow, torpedo-shaped body and the anterior end of the head forms a pointed-triangle. We think this critter might be a Rhincalanus spp.—if you look close you might be able to make out a small rostrum-like appendage extending forward and tucked down from the head, as well as what may be lateral spination at the end of each mid-body segment (prosome). This guy’s cruising, antennas spread out and scanning the surroundings. On the right, we have a copepod belonging to the family Metridinidae, perfectly poised for the ISIIS cam. How do we guess this ID? At the end of this copepods lengthy tail (urosome), look closely at the paired fin-like feature (ferka). Along the outer edge, right before the separation of the individual ferka, can you make out a small, skirt-like protrusion? If so, just tell your buddies: “hmm, check out that lengthy urosome and ferka segmentation; it must be a Metrinidae species,” and blamo—you are a crustacean taxonomist!
Anthomedusae: Leukartia spp.
At first glance, you might be thinking “is this medusae sticking its tongue out at me?” Or maybe it is sporting a ten-gallon hat? While I couldn’t blame you for such outlandish assertions (I mean, who would write such silly things?), this odd anthomedusae is readily identified to genus by the conical appendage extending from the bell (“apical process”) and causing much confusion on the Plankton Portal. In this image we get a great view of many internal and external features of this Leukartia sp., including a crenulated (ragged) bell margin, a tall mouth (“manubrium”) in the center of the bell, and many long tentacles projected both downwards and in front of the bell.
Larvacean and mucous house
We find a good deal of larvaceans on the site, but this capture is a real beauty. Larvaceans are gelatinous plankton that filter-feed on detritus in the water column. You see the critter poking its head out, like the cap on a rolled-up toothpaste tube? That’s the larvacean, curled up in preparation to pump surrounding detritus through its elaborate mesh-like mucous house. For a critter that takes up residency in its own secretion, this guy is pretty adorable!
Now this is quite the fantastic find! Here we are looking at a large siphonophore projecting numerous tentacles across the frame. It is all-hands-on-deck for this colonial jelly, as it is putting on a mighty foraging display for us. The big guy is hungry—watch out, ISIIS.
There have been way too many great images to fit in this small serving of photogenic plankton. We look forward to serving up more fantastic finds in the future. Keep exploring, plankton hunters!
Hi Plankton Portal!
The Science Team is currently out in the field in the Straits of Florida, on the R/V Walton Smith, sampling with both ISIIS and MOCNESS (Multiple Opening Closing Net and Environmental Sampling System), on an 18-day cruise titled OSTRICH (Observations on Subtropical TRophodynamics of ICHthyoplankton).
The overall goal of this NSF-sponsored project is to quantify the patterns and consequences of the fine-scale to sub-mesoscale distributions of larval fishes, their prey, and their predators near and across a major western boundary current passing through the Straits of Florida. By sampling a series of water masses at very high resolution, this study addresses specific hypotheses concerning: i) the drivers of aggregations and patchiness, and ii) the biological consequences of predator-prey interactions at fine scales.
Sampling involves a novel combination of detailed in situ sampling of the horizontal and vertical distributions of plankton, targeted fine-scale net sampling, and analyses of individual-level recent daily larval growth to enable the identification of the biological and physical processes driving fine-scale plankton distributions.
Follow along on the ISIIS facebook page as we periodically post updates (via our terrible internet connection at sea!) and also check out this cool video made by one of our cruise participants, Chris Muiña:
Hey plankton hunters! This week we are showing off four exceptional zooplankton found by you, our keen-eyed and inquisitive citizen scientists. We are amazed at how many plankton species have been uncovered on the site and just how capable you all have been at discerning some truly tricky taxa from the varying forms and shapes captured by the ISIIS camera. We thank all of the citizen scientists for your participation on the Plankton Portal! These images found by our citizen scientists continue to excite and we are eager to discover what resides in the thousands of images yet to be seen by human eyes!
Annatiara affinis; Anthomedusa — #Medusa #morethanfourtentacles
This capture of an anthomedusa is definitely a prime example of how the images captured by ISIIS can be equal measures fine-resolution biological data and one-of-a-kind organismal artwork. This gelatinous organism is baring all for us in this frame and we get a clear view of not only the striations on the exterior of the bell (the exumbrella) unique to this species and the fully extended tentacles, but also the central gastric pouch (stomach) appearing as the dark mass within the bell and the internal network of radial canals where digested food is transported. I think I can also see this critter blushing as ISIIS takes the snapshot! This medusa shown here is relatively uncommon in the images provided for you from the Southern California Bight, and we couldn’t be happier that our fantastic and dedicated group of citizen scientists spotted this gelatinous beauty. Annatiara affinis is a hydromedusa like many of the #4tentacles and #morethanfourtentacle medusae found on the site. The unique (and photogenic) lines appearing along the exterior of the bell were very helpful in pinning down an ID for this critter. From what we have seen, this seems to be a rare image captured of Annatiara where the tentacles are fully extended from the margin of the bell, and we are extremely grateful that this lovely jelly was so at ease in front of the ISIIS cam.
Shrimp — #Shrimp
This is one of the largest shrimps I have seen on the portal and provides a great side-view of the crustacean anatomy. The orientation of this shrimp with the abdomen tucked under the carapace (upper shell) and the antenna trailing sharply away from the head indicates that it is moving rapidly towards its posterior (bottom left of image), using a swimming stroke known as the “cardioid escape reaction”—slapping the abdomen shut and quickly propelling the crustacean away from the perceived danger. This specific behavior played an important role in the field of neuroscience, in fact. When it was discovered, this behavioral response was the first example of a “command neuron mediated behavior”— meaning a specific behavioral pattern resulting from the stimulation of a single neuron. I wonder what stimulated this crustacean’s command neuron? Perhaps it is camera shy.
Arrow Worm / Chaetognath — #ArrowWorm
I’m curious if that dark blob may be some out-of-luck plankter soon to be nabbed by this voracious predator. I am especially fond of these in focus captures of chaetognaths. The dart-shaped body and the hydrodynamic taper of the paired lateral fins really show off the sleek and elegant body plan of these brutal invertebrate carnivores. The chaetognath body has a protective outer covering known as a cuticle, a tough but flexible non-mineral layer exterior to the epidermis. Chaetognaths are notoriously efficient predators and hunt other planktonic organisms using hooked grasping spines that flank the mouth. A hood arising from the neck region can be drawn over or away from the hunting spines, much like the action of sheathing and unsheathing a blade. Equipped with an armor of cuticle and sword-like spines these guys are definitely well suited for combat!
Physonect Siphonophore — #Sipho #Corncob
The siphonophores love to put on a good show for us here on the portal and this frame is truly exceptional. The shadowgraph imaging technique used by ISIIS lends itself to capturing in detail the elaborate gelatinous structures displayed by these colonial organisms. Siphonophores are comprised of many single animals, or zooids, which are highly specialized and coordinated in function. The zooids of a physonect siphonophore arise from a long stem at the end of which is a gas-filled float referred to as a pneumatophore. The pneumatophore is on display in this image here appearing as the dark, oval-shaped appendage on the upper left end of the main “body.” The portion that resembles a corn on the cob is referred to as the nectosome. The nectosome is composed of many swimming bells, or nectophores, each one of which is a single medusoid zooid. These nectophores display remarkable coordination among each other and the selective contraction of these zooids allows for the siphonophore to move and turn in any and all directions. Physonect siphonophores are predators and rely on long, branching tentacles for prey capture. The one whipping across the frame here is definitely on the prowl. Each tentacle arises from a single feeding polyp situated below the nectosome in a region called the siphosome. You can see the siphosomal region on this specimen as the narrowing, darkly filled feature curling upward from the base of the nectosome. They sure have a lot of ‘somes’ and ‘phores’ but we forgive their repetitive nomenclature because we are always glad to find some siphonophores.
We hope this has been a fun and informative look at a few of the many tremendous critters captured by ISIIS and found by the citizen scientists. If you come across an image you think is particularly cool on the portal then tag it with #FFF and we will check it out for use on the blog. As always, looking forward to the next Fantastic Find Fridays!
Hello everyone. We have a special “behavior” Fantastic Finds Friday (FFF) today! These frames were selected from your posts to illustrate the power of the human eye to detect rare and unusual phenomena. The frames selected here may not be the most beautiful you have seen so far, but the story behind them is fascinating and could not be told without the help of our citizen scientists.
Here is great shot of a larvacean (also known as an appendicularian) getting spooked by the movement of ISIIS. Larvaceans are known to escape from their mucous house if threatened by a predator. Unfortunately the house can’t be used again, and they will start secreting a new house once the threat is passed.
Arrow worms (chaetognath) are voracious predators capable of engulfing prey as big as their own body. In these images, you can see an arrow worm catching a larvacean and the other grasping what appears to be a copepod. Their mouths resemble a crown of spikes ready to impale any unlucky prey. Chaetognaths also prey on fish larvae.
These two medusae just snagged a larvacean house. Accident or deliberate attempt to feed on these poor guys? The long trailing tentacles act like a sticky fishing net that retracts to bring in the catch of the day.
These Solmaris seem to be reaching for something (one tentacle pointed opposite to the others). Solmaris have been seen feeding on other jellies – even large siphonophores! They swim with their tentacles forward to maximize the chances of catching a prey. they then move the item to their mouth with one tentacle (like an arm almost).
No, these are really two different frames! Amazing consistency in posture isn’t it? And look at these two tentacles reaching out – sensing their environment? Hoping to encounter a tasty prey item? If we detect enough of these organisms, we could try to investigate at which time or location they behave this way. This could be a really interesting project!
So if you see something interesting like these example or suspect some interaction is at play in one of the frame use the hashtag #behavior. Remember to mark frames you want considered for future Fantastic Finds Friday posts with #FFF. Thanks, and keep up the good work!
We are nearing the end of Friday, so apologies that this post is late! Hopefully it will be enjoyable for you weekend warriors! By the way, did you see that we are almost at 200,000 classifications?! I am so impressed by this amazing group of citizen scientists that make Zooniverse projects a success, particularly this one. THANK YOU.
We are going to use FFF to point out some amazing pictures that you guys have identified and called to our attention in the last week+, and also to clarify some confusion on a tricky category.
Cydippid ctenophore – #cydippid
This is a type of comb jelly, called a cydippid ctenophore. We think that this organism is Hormiphora californiensis or a relative. It has a egg shaped body with two tentacles, which are typically extended (for feeding), but also can be retracted into the sides of its body.
The relative of Hormophora californiensis is Pleurobrachia bachei, the sea gooseberry. Check out the following video of P. bachei feeding on some brine shrimp:
Here is another video of P. bachei from the Vancouver Aquarium:
For every easily classified cydippid ctenophore there is also other cydippids that are more difficult to classify by users. These ctenophores include Mertensia and Haeckelia beehleri, which are also cydippids but have their tentacles withdrawn. See below:
This is also a cydippid ctenophore – but it has its tentacles withdrawn.
To add some more complication to the matter, there are also some lobate ctenophores, like the one below, whose young have a cydippid-like phase.
Lobate ctenophore – #lobate
This is a beautiful shot of an adult lobate ctenophore, most likely the species Ocyropsis maculata. However, their young have this cydippid-like phrase. There has been one paper that published a drawing of the development of Ocyropsis. It was published in 1963. I had to email all around to get a copy, and when I receive it, I see that it’s in Chinese. Fortunately, they had great drawings that helped me.
If anyone can translate the Chinese, let us know! But otherwise, just look at the cool pictures. There are a couple different stages of lobate ctenophore development, and the cydippid stage is one of the earliest stages. We definitely see this stage in our images. See below:
Cydippid-phase of young Lobate Ctenophore
Officially, we want you to make this as a #lobate. BUT, we also know that these are incredibly confusing because these ctenophores have tentacles. So, we understand if you get these mixed up. In our data cleanup, we will end up checking the classifications of the small cydippids and lobates to make sure that they are classified correctly. Also, please know that if you do mix these classifications up, we will at least know that it’s a ctenophore! That’s more information than we had previously. So, anything is helpful.
THAT’S ALL FOLKS! Thanks for reading. Remember to tag images you want considered for Fantastic Finds Friday with the hashtag #FFF. And as always, thanks for classifying! We are currently at 191,968 classifications. So very close to 200,000!
Also known as Comb jellies or sea gooseberries. The name comes from the Greek Ctena (comb) and Phora (bearer). They first appeared more 500 million years ago!
These are plankton predators which can swim with the help of a several rows of cilia. Some catch their food with long fishing tentacles laden with sticky cells (colloblast) like the #Cydippids.
Others can engulf their meal directly like the #Lobates. They can consume anything from other ctenophores, copepods to fish larva. The weirdest of all is the #Cestida which body plan is totally flat, yet it has all the attributes the Ctenophore group!
One species (Mnemiopsis Leidyi) was accidentally introduced in the black sea via ship ballast water coming from the Atlantic Ocean. Result: local fisheries collapsed due to M. Leidyi appetite for fish larvae.
Here is an amazing Ctenophore video from our Plankton Chronicles colleagues. Shimmering waves of light, stalking their prey, ctenophores are on the move.
Plankton Chronicles Project by Christian Sardet, CNRS / Noe Sardet and Sharif Mirshak, Parafilms
See Plankton Chronicles interactive site: planktonchronicles.org
A big congratulations to Dr. Adam Greer, who defended his dissertation on Friday. The title of his dissertation is, “Fine-scale distributions of plankton and larval fishes: Implications for predator-prey interactions near coastal oceanographic features”
In our Ph.D. dissertation defenses, we give a 1-hr talk on our research (imagine trying to cram in 5+ years of work into 1 hour!) and then we have a closed-door session with our Ph.D. committee where we answer questions and ‘defend’ our research.
Adam did fabulously on Friday and successfully defended! He will be finishing the writing this month and then moving to on as a Post-doctoral researcher at the University of Georgia. Congratulations, Dr. Greer!
Hey plankton hunters! Welcome to our 3rd round of Fantastic Find Friday here at Plankton Portal. There have been so many awesome finds on the site and we picked 5 this week for you to check out. If you see something really neat on the portal than tag it with #FFF so we can check it out for use on the blog. Here we go!
Physonect Siphonophore— #Sipho #Corncob
This is a stunning capture of a physonect siphonophore who seems to be waving hello to ISIIS as she passes by. Like all siphonophores, this guy here is a colonial organism comprised of many individual animals or ‘zooids.’ Each zooid is specialized and distinct, but work together so closely that they more resemble a single organism than a colony of animals. On display here are the branching tentacles used for foraging and the swimming bells that resemble a corncob. This one is a stunner!
Lobate Ctenophore — #Lobate
This is a really neat capture of a lobate ctenophore (Ocyropsis maculata), showing off the feature that gives this guy his name. In this image you can see clearly the internal structure and the striated texture of his muscular, gelatinous body. Lobate ctenophores swim lobes forwards by beating the ciliated comb rows situated on the opposite (aboral) end. The one depicted here would be swimming towards us and to the left. I wonder if larvacean is on the menu?
Chaetognath — #Arrowworm
Looks like an arrow shot by some undersea archer, right? Arrow worms, or chaetognaths, are carnivorous marine worms belonging to the Phylum Chaetognatha. They are notoriously ferocious predators that hunt other plankton with the help of hooked ‘grasping spines’ that flank the mouth. Chaetognaths have fins for propulsion and steering—you can see all of them really well in this capture! While these fins superficially resemble those of a fish, they are not related evolutionary and are structurally very different.
Calycophoran Siphonophore — #Rocketship #Triangle
I bet NASA would get a lot more funding if they built space shuttles that looked like this! This beautiful capture of a siphonophore really looks to me like some sci-fi monster a (horrified) astronomer might see in a telescope! Don’t worry though, this guy is just a couple of cm’s long and probably couldn’t hurt you if he tried. Just like the physonect siphonophore above, this guy is a colonial organism and would therefore be more appropriately referred to as guys. The tail, or stem, on display here contains two developmental stages of siphonophore simultaneously—both the medusa and polyp stages. Unlike most cnidarians that alternate between these stages generationally, this guy chooses to have them coexist within the same colony. If you look closely you can see them bickering over who is the prettiest!
Calanoid Copepod — #Copepod
This copepod is making a heart with his antennae! Do you think he might be in love? There is some 13,000 species of copepod in the world and they are a crucial component of plankton communities and global ecology in general. It has been suggested that copepods may comprise the largest animal biomass on the planet! Many species of marine life, large and small, rely on these guys as their main food source, including whales and seabirds. Looks like this guy here is a lover not a fighter!
Looking forward to next time !
The underlying objective of this research project is centered on a small-scale front and its associated biological activity. A front is a meeting of two water masses, and oceanic fronts are generally broken up into several broad categories, depending on the physical environment and phenomenon that cause these water masses to converge. Oceanographers have been interested in fronts for a long time, because they tend to be areas of high productivity. The elevated productivity at fronts is a result of the converging water masses physically aggregating many marine organisms.
Small-scale fronts are, as the name suggests, smaller in spatial scale: they tend to occur on the order of tens of kilometers instead of hundreds to thousands of kilometers like some of the other major fronts. Small-scale fronts occur frequently, but have also been harder to describe because they are more ephemeral than large fronts.
We set out to study one particular small-scale front in the Southern California Bight (SCB, see map for study region) because it was in an area that has received long-term oceanographic investigation – it is always good to do studies where there is lots of baseline data. We were primarily interested in exploring what biota was out there and seeing if there was biological aggregation at the front. Indeed there was! We saw a large aggregation of our now favorite jellyfish, Solmaris rhodoloma, at the front and described it in a 2012 research paper. You don’t have to worry about reading it. It basically says what I just told you: we found a lot of Solmaris at this small-scale, salinity-driven front.
One of the interesting things about Solmaris is that they are part of a family of medusae that predate exclusively on other gelatinous zooplankton. They have been known to eat arrow worms and doliolids, but now, because of our images, we also think they are eating larvaceans and small siphonophores as well. So finding the large aggregation of Solmaris actually generated another research question for us: what’s going on with the rest of the gelatinous zooplankton at and around this front? What are the main processes driving their distribution? Is predation pressure from Solmaris affecting them in any way?
It turns out that the second question is much harder to answer than you would think. Not knowing exactly what Solmaris is eating, and how long they’ve been accumulating at the front makes it difficult for us to tell if they’re just happening upon a patch of prey or they have already eaten everything around them. One approach is to determine the movements and directions of the organisms, which is why we’re asking you to measure their orientation. We hope that knowing their orientation (and that of their potential prey) can help us model their movement patterns and “age” the Solmaris aggregation, so to speak. Of course, it’s possible that even with this data we will still not be able to determine how long Solmaris has been aggregating at the front. However, this kind of orientation information has never been acquired for jellyfish of this size and at this scale, so any data we gather will be new and interesting!
This is just one of many questions that Plankton Portal can help answer. The biological data contained within these images can bring us closer to a greater understanding of zooplankton ecology in general. Understanding the abundance, distribution and biomass (that’s where the size measurements come in) of this extremely understudied group of organisms – the small gelatinous zooplankton – can help us assess their broader impact in the marine food web, contribution to carbon cycling, and even help us learn how to identify hotspots of marine productivity in the future. This is how research grows and develops: it starts from a small, initial question (“hmm, I wonder if there is anything interesting at a small offshore front?”), which leads us to additional questions, and down the road, will hopefully help mankind appreciate and better protect its precious marine resources.
Thank you for your help and participation in Plankton Portal – you are contributing to a more knowledgeable future and hopefully one where we can better care for the sea around us.