Fantastic Finds Friday #FFF – Cydippid edition

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 These ctenophores include Mertensia and Haeckelia beehleri, which are also cydippids but have their tentacles withdrawn.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This is also a cydippid ctenophore – but it has its tentacles withdrawn.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.


Chiu SY (1963) The metamorphosis of the ctenophore Ocyropsis crystallina from Amoy. Acta Zoologica Sinica 15:10-16

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!

Drifter science!!

Here is a very funny educational video from the Carthe group (University of Miami). How physical oceanographers study and track currents and why it is important.

Very useful data if you want to know where our precious plankton is going! Just watch! funny and instructive.

Video credit: Laura Bracken (CARTHE), Patrick Rynne (Waterlust) and Fiona Graham (Waterlust), Sharon Chinchilla (CARTHE) and Jennah Caster (Waterlust)

Ctenophore, a soft bodied but voracious predator

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!


A little Beroida

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.


Cydippid showing its deadly tentacles

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!


Lobate ctenophore ready to engulf anything in its path.


Cestida the weirdest of all. it body is flat and shaped like a ribbon

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:

Congratulations to Dr. Adam Greer!

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”

FirstSlideIn 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!

What’s the goal of this research project?

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.


Sampling region in the Southern California Bight (SCB)

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.

Solmaris rhodoloma aggregation

Solmaris rhodoloma aggregation

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.

Fantastic Finds Fridays: Week 2! #FFF

We are at the end of week 2 and we pulled out some of the best finds from this past week. As a reminder, every Friday we will post a selection of Fantastic Finds. If you think you have found something really great on Plankton Portal then tag #FFF and we will check it out for use on the blog. Thanks for tagging your favorites this week!


Larval fish

Larval fish are actually considered part of the plankton, as fish in their early life stages will drift along in the oceanic environment. Because larval fish are relatively poor swimmers, they are under high predation pressure and more than 99% of baby fish that hatch from eggs will not make it! It’s a tough life. You might not know it from this site, but studying larval fish is a major component of our lab. Dr. Cowen has spent his career studying larval fish, their distributions, dispersal and population connectivity. In this particular study, we did not sample very many larval fish so we did not include it as one of the categories. However, we are incredibly interested whenever we see one so definitely tag the fish in the forum when you see any! #Larval #fish


Liriope tetraphylla (#Medusae #4tentacles) with Arrow worm

This is one of my favorite pictures from this week because what you see Liriope tetraphylla actually eating the arrow worm! Here one of his tentacles has brought up the arrow worm into the gastric peduncle (that’s the long thin appendage in the middle of the umbrella that looks like a handle). He appears to be holding the arrow worm in place while he eats his dinner. As far as I know, the only scientific study of what Liriope eats is from a paper by Larry Madin in 1988, published in the Bulletin of Marine Science, where he found that Liriope eats larvaceans, crustacean larvae, heteropods and juvenile fish. No one has reported that Liriope also eats arrow worms … until now.


Sphaeronectes koellikeri – #rocketship #thimble

This beautiful creature falls within the broad group of jellyfish-relatives called the Siphonophores. Here you see this animal in a stunning feeding display. Though these guys are small and relatively inconspicuous, other siphonophores can get up to hundreds of feet long, and as a group are considered the deadliest predators in the ocean.  One fun fact: these rocketship siphonophores grow from the base of the stem towards the tail end. So the tail end of the stem is one of the oldest parts of the body. Sometimes you’ll even see small rocketships budding from the tail!


Radiolarian colony – #radiolarian #colony

We know that you’ve been frustrated by those small fuzzy round objects that invite classification but really aren’t supposed to be classified. Those are protists, a diverse group of eukaryotic microorganisms. One type of protist is the radiolarian, which are known for their glass-like exoskeleton, or “tests.” They are incredibly important in marine science because their tests are made of silica, which are preserved in marine sediments after they die and sink to the bottom of the ocean, and provide a record for paleo-oceanographic conditions, such as temperature, water circulation, and overall climate.

Radiolarians also form colonies. Colonial radiolarians are interesting because first, little is known about them, despite their abundance in the open ocean, and secondly, they are hosts to symbiotic algae that are modest but significant primary producers in the ocean. It has also been suggested that we are vastly underestimating the abundance of radiolarian colonies. Since primary production (photosynthesis, the conversion of sun energy into carbon) is the basis upon which all ocean life can exist, it’s incredibly important to understand who all the different primary producers are and how many of them are out there!


That’s all, folks. Thanks for reading, thanks for classifying, and remember: mark your favorites with #FFF for next week’s Fantastic Finds Friday!

Why do we need Citizen Science?

In many fields of science, new technology is leading to unprecedented data production. This, in turn, requires extensive analysis with minimal sub-sampling to detect as much detail as possible. In biological oceanography, imaging systems have become more useful with increasing computer speed and storage capabilities, and image data address some of the fundamental problems with traditional sampling methods that are destructive to fragile organisms (i.e., jellyfish and marine snow). On a given tow with our system, the In Situ Ichthyoplankton Imaging System (ISIIS), we produce approximately 400,000 images in 7 hours with many different species across a range of sizes present in each image (500 μm to 13 cm). This is an incredible amount of information that would take years for one person to fully analyze. When we are out at sea, we typically sample for WEEKS and come back to land with millions of images. Computer algorithms can perform basic tasks of extracting specimens that look similar, but human brains are extremely adept at interpreting an organism in 3D and providing context in the image data that a computer cannot. The amazing abilities of people to recognize patterns that computer algorithms may see as unimportant cannot be underestimated.

Shrimp photograph taken from under a microscope

Shrimp photograph taken from under a microscope (photo credit: Cedric Guigand)

Another reason we are using Citizen Science is so that you, the citizen scientist, can participate in the process of discovery. After all, most oceanographic research is funded at least in part by taxpayer money, and these novel plankton images combined with Citizen Science are a great way to engage those who fund the research. We think it is far more effective to cultivate interest in science through the discovery process itself, rather than the production of jargon-filled reports and papers only understood by other oceanographers (don’t worry, those will come later). In addition, this online format provides an opportunity for us to educate people about life in the oceans, potentially inspiring the next generation of ocean scientists. With Citizen Science, there is the potential for new discoveries arising from simply allowing many people to look at the images.

This larva of a deep water shrimp was captured in the Gulf Stream near South Florida (Photo credit: Cedric Guigand)

This larva of a deep water shrimp was captured in the Gulf Stream near South Florida (photo credit: Cedric Guigand)

We believe our research with ISIIS is particularly applicable to Citizen Science and the process of discovery because this new imaging technology provides a huge amount of data and a unique glimpse into ocean life. I have spent the last 5 years of my graduate school career at the University of Miami examining hundreds of thousands of plankton images, and every time I flip through the images, I always have the feeling that I could see something that no human has ever seen before. I try to instill this sense of wonder and hope for discovery in all people that work with the images, because when you see something interesting, like an elaborate siphonophore or a dense patch of copepods, you are likely the first person to see that species in its natural environment. When we get enough eyes on these images and discussions facilitated through the Plankton Portal website, the sky’s the limit for the discoveries that can be made with Citizen Science!

Amazing Plankton Videos

Hi all! we wanted to share this website, called Plankton Chronicles, with you. It is an amazing collection of plankton related mini videos. You’ll get to see some color videos of your favorite plankton. Who knows? it may also help you in your classification effort. Enjoy!


The Plankton Chronicles series was created by Christian Sardet (CNRS), Sharif Mirshak and Noé Sardet (Parafilms) in the context of the Tara Oceans Expedition and the Marine Station of Villefranche sur Mer (CNRS / UPMC). The series has received financial support from CNRS (INSB / INEE), IBISA, UPMC and the Ville de Nice.

Why do the images look the way they do?

As you may know by now, the In Situ Ichthyoplankton Imaging system (ISIIS) is the instrument we used to obtain the images of plankton for Plankton Portal.  It captures images as it travels through the water column.  The idea behind this imaging system was to film a large volume of water in order to detect and image relatively rare zooplankton, like larval fish and small jellies.

So why are the images are black and white, very contrasted and almost like a line drawing? Our challenge in designing this instrument was to be able to employ macro-photography at a fast speed, obtain a large depth of field (large volume sampled), while minimizing motion blur. After researching for a few months we settled on an imaging technique that could answer our demands: Shadow imaging or focus shadowgraphy!

Gary setlles

a) prehistoric shadowgraphy, b) sunlight shadowgram of a martini glass, c) “focused” shadowgram of a common firecracker explosion, d) “Edgerton” shadowgram of the firing of an AK-47 assault rifle
Gary S. Settles

This technique is actually not new and was used extensively for the study of shockwaves as well as ballistic. The idea is to cast a shadow onto a sensor or film instead of trying to directly record the imaged object. Let me explain: since most plankton are small and quite transparent, imaging using a traditional camera must rely on ambient sunlight. In this scenario, you won’t see much because the organisms blend into the surrounding water. Imaging a shadow cast by ISIIS reveals their distinct shape and location. It’s like looking at the shadows at the bottom of a swimming pool created by the sun going through the water! In this case, we do not use the ambient sunlight, but create our own light beam using a blue LED light and a set of mirror and lenses. The light is collimated, meaning that the light beam travels in a tight, parallel direction like that of a laser thus ensuring that even over long distances, we can create a very good shadow. We then use a specific set of lenses aligned with the camera to capture this shadowgraph image. Since the light beam is directed toward the camera sensor, it allows for very high speed imaging and avoids motion blur when moving through the water. Lastly, we invert the images for aesthetic purposes on the site, and voila! Now you have a beautiful set of black and white images of plankton for the world to see!

isiis optics

This schematic shows the optical alignment inside ISIIS. A bean of light is collimated by a large lens and the refocused after going through the water. The camera records the shadows casted by the plankton as the moves behind the ship

So for all the people who asked about why some of the ctenophores (like lobates, beroids, and cydippids) were so ‘overexposed,’ now you know. These animals are dense and not very transparent, thus casting a hard shadow onto the lens. Instead of appearing black as a typical shadow, we have inverted the image and now they appear white.

lobate ex

Lobate ctenophore