From the citizen scientists: #FFF

Posted on November 29, 2013 by jessicaluo

This week, we asked one of our top volunteers, Zuzana, a very lovely lady from the Czech Republic, to pick her favorite images for a special Fantastic Finds Friday (FFF) post. She went way above and beyond — did research on her own, wrote up information and background — and we are very pleased to present to you this week’s #FFF post.

Hello everyone. My name is Zuzana, also known as the user Yshish. I was asked by Jessica of the scientist team to put together my favorite pictures from this amazing Plankton Portal and write a short FFF post about them. So here they are:

*The first of my most favorite finds for the last week is definitely this beauty – Aegina citrea.

[http://talk.planktonportal.org/#/subjects/APK0006f6z]

This image of Aegina citrea was captured at a depth of 43.42 m and at temperature of 13.55°C.

Aegina citrea

Aegina is one of the jellyfish belonging to the Narcomedusae Order, like its more familiar relative Solmaris.

Members of this order do not normally have a polyp stage. The medusa has a dome-shaped bell with thin sides. The tentacles are attached above the lobed margin of the bell with a gastric pouch typically found above each. There are no bulbs on the tentacles and no radial canals. Narcomedusa are mostly inhabitants of the open ocean and deep waters.

A. citrea is a very rare species in the Plankton Portal images but if you were lucky to get an image with it, mark it as a 4tentacles medusa and start a discussion with using #Aegina tag.

An additional note: Narcomedusa ‘babies’ are very interesting, and act as parasites on other jellies after exiting the mother! Check out this link:

CreatureCast – Narcomedusae from Casey Dunn.

* The second find I chose for this post is my favorite species: ‘Thalasso’ – Thalassocalyce inconstans.

This is a compilation of three separate Plankton Portal images. The Thalasso on the top right was caught while feeding! You can see him opening his ‘mouth’ widely to catch something tasty in the water!

Thalassocalyce inconstans, which we have nicknamed ‘thalasso’ on the Portal, belongs to the phylum Ctenophora – the comb jellies. The Order Thalassocalycida contains only one known species first described in 1978 [Madin and Harbison 1978]. They are closely related to the other ctenophore Orders such as Lobata, Cydippida and Cestidae.

They have an extremely fragile body that can reach 15 cm in width and is shortened in the oral-aboral direction. Thalassocalyce have short comb-rows on the surface furthest from the mouth, originating from near the aboral pole. They capture prey by movements of the bell as you can see in the pictures.

To me they look like an opened umbrella with a beautiful distinct linear drawing engraved on it. Their look is simply beautiful!

Also I can’t forget to mention that I’m fascinated by their bioluminescent abilities. The wavelength of the emitted light from Thalassocalyce is 491 nm (SHD Haddock & JF Case 1999).

* The third fantastic find is this beautiful ‘Corncob Sipho’ – Physonect siphonophore – Forskalia genus.

[http://talk.planktonportal.org/#/subjects/APK00029a8]

Physonect siphonophore

The Siphonophores are an order of the Hydrozoa, a class of marine invertebrates belonging to the phylum Cnidaria which include coral and ‘jellyfish.’ Although a siphonophore appears to be a single organism, each specimen is actually a colony composed of many individual animals. Most colonies are long, thin, transparent organisms that float in the open ocean.

All of the zooids of a physonect colony are arranged on a long stem. This stem has a gas filled float known as a pneumatophore at one end. That’s the funny ‘nose’ we are used to seeing and are typical of the Physonectae family of siphonophores.

Just behind the pneumatophore are the nectophores. These are powerful medusae specialized for moving the colony through the water. They contract in coordination, propelling the entire colony forward, backwards, and in turns. The region of the colony containing the nectophores is called the nectosome.

Just behind the nectosome is the siphosome, which has all of the remaining zooids of the colony. These include feeding polyps capture food with their single, long tentacle, providing nourishment for the entire colony. [http://www.siphonophores.org/SiphPlan.php]
Siphonophores catch prey by putting out their long tentacles and waiting for something to bump into them.

Here is a nice schematic of a physonect siphonophore which could help you understand these awesome creatures:

Physonect siphonophore diagram – Casey Dunn

* My fourth pick is another Siphonophore, this fascinating ‘Thimble Rocket-ship’ – one of the Sphaeronectes genera captured here in a stunning feeding display.

[http://talk.planktonportal.org/#/subjects/APK0005o03]

You can see that he’s able to cover all the space around himself with his branching tail. It looks almost like a spiderweb to me. In this position he’s waiting for other plankton swimming around to catch and eat.

As I mentioned above, Sphaeronectes is a genus of the Siphonophorae order.

Most siphonophores capture their prey by trapping it with special side branches (termed tentilla) which originate from the tentacle of each gastrozooid. During feeding, the tentilla and the tentacles are extended into the water to form a large transparent net. The prey is first ensnared by the terminal filament and its entangling cnidae (stinging cells). The terminal filament then contracts, bringing the prey into the cnidoband, which contains many stinging cells. (Mackie and Marx 1988; Mackie 1999). [Siphonophora (Cnidaria: Hydrozoa) of Canadian Pacific Waters. Gillian M. Mapstone,Mary N. Arai]

* My final favorite find is this fish – probably a Clupeid (Herring)

[http://talk.planktonportal.org/#/subjects/APK0004ajk]

Clupeidae is the family of the herrings, shads, sardines, hilsa and menhadens. It includes many of the most important food fishes in the world. Clupeids typically feed on plankton, and range from 2 to 75 centimetres in length. After hatching, the larvae are planktonic and live among other plankton until they metamorphose and grow into adults. The adults typically live in large shoals in the coastal oceans.

The larvae are 5 to 6 millimetres long at hatching and have a small yolk sac for nourishment that is absorbed by the time the larva reaches 10 millimetres. Only the eyes are well pigmented while it is a larva. The rest of the body is nearly transparent, virtually invisible under water and in natural lighting conditions.

The larvae are very slender and can easily be distinguished from all other young fish of their range by the location of the vent, which lies close to the base of the tail and is an opening for excretion of eggs and sperm. But distinguishing clupeids from other types of larval fish at this stage requires expertise and close examination. ISIIS images are of a high enough resolution to allow experts to determine the taxa of larval fish captured in the data!

I hope the article wasn’t too boring for you and that you have enjoyed reading it as much as I’ve enjoyed writing it. And do not forget, if you think you’ve found something really neat on the Portal use hashtag #FFF in the discussion boards. I can’t wait to see what else will be found next! Big thanks to Ben Grassian for the consultations!

-Zuzana

Arrow worms: voracious plankton predators

Posted on November 21, 2013 by agreer35

You may think orcas or great white sharks are the most voracious predators in the oceans, but based on their abundance and ability to consume a wide range of prey items, chaetognaths (a.k.a. “arrow worms”) give those big animals a run for their money. Large predators like sharks are extremely rare, but scoop up a bucket of seawater almost anywhere in the world and you are likely to find a few chaetognaths (if you have a microscope handy). Chaetognaths are transparent worms that often remain motionless in the water column, apparently relying on the element of surprise to capture a wide variety of plankton, including copepods, appendicularians, small fish larvae, and smaller chaetognaths. Chaetognaths are thought to be generalist feeders because their stomach contents often reflect the community captured by plankton nets. They use a mass of chitinous hooks around their mouths to capture prey – which gives them their name (“chaetognath” translates from Latin to mean “hairy jaw”) and a notoriously menacing appearance.

Chaetognaths are often straight in the ISIIS images but can also swim rapidly for short distances. The camera typically cannot resolve the tiny chitinous hooks on the chaetognath’s mouth.

Chaetognaths comprise about 100 species that are all typically 1-2 cm long. They are most abundant along the coasts, with some species being so sensitive to salinity that oceanographers can identify discrete water masses based solely on the community of chaetognath species. Similar to many other types of zooplankton, chaetognaths are hermaphrodites, first being male then changing into female as they get larger. Fertilized eggs can be attached to vegetation or encased in a gelatinous web. Eggs then hatch into juvenile chaetognaths, and thus they have no larval stage. This is called direct development because there is no process of metamorphosis.

A clear image of the chaetognath’s mouth on the cover of Current Biology.

The chaetognath’s body is streamlined and adapted to feeding with minimal visual input. The have sensory cilia that can detect small vibrations in the water that tell the chaetognaths that prey is within striking distance. With a quick flick of its tail, the chaetognath surges forward to capture the prey in its chitinous hooks used for grasping. It then transfers the prey to its mouth where it is swallowed whole. Some deeper water chaetognaths (>700 m deep) can even use bioluminescence to create a cloud of light that scientists think can be used to escape predation (Haddock and Case 1994).

The most handsome chaetognath found by our citizen scientists!

References:

Haddock SHD and Case JF (1994) A bioluminescent chaetognath. Nature 367:225

Johnson WS and Allen DM (2005) Zooplankton of the Atlantic and Gulf coasts: A guide to the identification and ecology. Johns Hopkins University Press, Baltimore, MD

Lalli CM and Parsons TR (1997) Biological oceanography an introduction. Elsevier Butterworth-Heinemann, Burlington, MA

Jellyfish blooms, Norway and Periphylla

Posted on November 19, 2013 by jessicaluo

Today’s post comes from a new blog started by Andrea Bozman from the University of Nordland, Bodø, Norway. She is a Ph.D student studying the Helmet Jellyfish, Periphylla periphylla. From Andrea’s blog, www.smackofscience.com, she weighs in on the question of whether jellyfish blooms are increasing. In Norway and in many other areas of the world, people are worried that menace jellyfish might be eating all the young fish, devastating vital fisheries. And increasing jellyfish blooms only make matters worse. Is this the case? Actually, the jury is still out — some scientists are saying that jellyfish blooms are natural and just a part of a global cycle, while others say that jellyfish are increasing due to human-caused degradation of the marine environment. This kind of debate is healthy in science, and the conversation worth following.

Here chimes in Andrea.

Andrea Bozman from The University of Nordland, Bodø, Norway

Revenge of the blobs

Jellies have made a name for themselves in the news, without much effort on their part. Numerous stories linking jellies with negative events are reported world over. In tropical locations this is normally associated with stingers, those jellies that can prove fatal upon contact. Here in Norway, we are not exposed to such angry jellies, but their less hurtful relatives can have economic consequences for industries such as aquaculture and fisheries. In 2011 an influx of jellies in Kaldfjorden sunk a salmon net cage, resulting in an approximate 30 tonne loss of fish. However, the presence of jellies is not a new problem for Norwegian waters. We have our own contender that is rather happy up here – Periphylla periphylla.

Periphylla periphylla, a coronate jellyfish capable of living at depths of 200 – 2000 m. Photo credit: Erling Svensen/savethehighseas.org

The jelly juxtapose

Interactions between fish and jellyfish are not always a bad thing. Some jellies are known to eat fish, others are eaten by fish, and still others provide protection for young fish. Instead of assuming negative connotations on the easiest target – the soft-bodied blobs floating around in our seas – we need to conduct thorough studies on the systems. The increase in reports of jellies may be a compounded effect of media interest rather than an increase in actual jelly numbers. Jelly blooms are nothing new. Well preserved blooms have been found in the fossil record. That said, a change in the location and numbers of some jellies is a fact. And Periphylla in Norway is a prime example.

Yet like jelly blooms, the Periphylla story is also complex. Periphylla is one of the most globally distributed jellies and has always been in Norway. Why numbers are increasing in some areas is unclear. The occurrences may be new or may be part of a cycle. Periphylla is long lived and it may take years for an individual to reach the adult stage. The recent increased numbers in some fjords may have been years in the making. Our knowledge of jellies needs to grow as jellies are likely both misunderstood and underestimated players in the fjords.

Check out the whole blogpost at: http://smackofscience.com/2013/11/15/the-good-the-bad-and-the-jelly/

Thanks for continuing to help out with Plankton Portal! Help from volunteers like you contribute to our understanding of the life histories, distributions and behavior of jellyfish. This information is crucial to have to better understand how jellyfish blooms happen and whether they are increasing globally.

Fantastic Find Friday: Back to Basics

Posted on November 15, 2013 by bgrassian

Welcome to this week’s edition of Fantastic Finds found by our dedicated and keen-eyed community of citizen scientists here on the Plankton Portal. As the weeks pass we are continually surprised by the sheer number of exciting and unique finds on the site. There is rarely a dull moment here on the portal and we greatly appreciate our many users for their continued input and insight. We have selected 5 stellar frames from a large collection of truly exceptional finds. If you stumble upon an image you think is special select finish, click discuss, and tag it with #FFF for recognition on the Friday posts. And off we go!

Salp; Ritteriella retracta – #Salp

We are out of the gate running this week with this awe-inspiring, in-focus capture of a Salp. What a lucky guy; most Salps don’t get the 5-minutes of fame they deserve! It reminds me of some organic, underwater vacuum cleaner, which is not a far stretch given the foraging method these guys employ. Salps are pelagic (open ocean) Tunicates that pump surrounding water through their tubular bodies, filtering out tasty organic matter with internal feeding structures, which are clearly visible here. Yum!

We’d like to give a big ‘shout out’ to Elena Guerrero of Instituto de Ciencias Del Mar, Barcelona, Spain for the species-level ID.

Also, many thanks to user Yshish for this one which is perhaps my favorite find thus far on the site. Since my work focuses on ctenophores, this may be a blasphemous statement. I hope this assertion acts as incentive for the ctenophores to step up their game!

Pleurobrachia bachei – #Cydippid #Ctenophore

This species of ctenophore is as classic a morphology as you can find within this phylum. You can clearly see the eight ctene, or comb rows with the two on either side giving us an exceptional visual of their ciliated, hair-like structure. These comb rows are used both for feeding and for locomotion. If you look closely, you can also see the tentacle sheaths running internally towards the center oral canal, or ‘stomodaeum.’ The tentacles are extended here for foraging, but can be retracted into the body via the tentacle sheaths. This is one of the larger cydippid ctenophores I have seen on the site and is a stellar capture!

Siphonophore; Family Prayidae – #Rocketship #Thimble #Siphonophore #Behavior

This capture of a prayine Siphonophore is a truly special find. It seems ISIIS was at the right place at the right time as we captured this siphonophore in the process of asexually budding individual clonal copies of itself, also known as Zooids. Siphonophores are colonial organisms composed of many specialized zooids, or single animals that together comprise the colonial animal, referred to as a zoon. These individual zooids bud off from the stem of the siphonophore, which is the phenomenon on display here! I am personally very glad that our species cannot reproduce asexually—could you imagine if that bully who teased you in middle school could make multiple clonal copies of him/herself? I don’t think I would have survived all of those wedgies!

Cestid Ctenophore – #Cestida #Ctenophore

Yet another really neat capture of the ribbon-like Cestid Ctenophore. Although it may not appear like the cydippid ctenophore above, they both share many characteristics. You can see here the comb rows along the top (oral) side of the organism, on the right side of the guy captured in this frame. Like the cydippid ctenophores, these comb rows are used for both locomotion and foraging. The stomodaeum, or oral canal is also visible here, seen as the apparent crease along the oral-aboral axis in the mid-section of the organism. When it comes to locomotion, the Cestid ctenophores have a trick up their sleeve, able to move through the water column via undulation of their body. This is what we are witnessing in this capture here. Either that or this guy is dancing for the ISIIS camera.

Post-Flexion Larval Fish – #Fish

Another really great find of one of the rarest organisms in this data set—fish larva, or ichthyoplankton! The taxonomic ID for this guy is either an Engraulid (anchovy) or a Clupeid (sardine). This one here is quite big, and is a post-flexion larval fish. Larval fish pass through three substages, if they are lucky enough to survive during this extremely vulnerable period: preflexion, flexion, and postflexion. These stages are in reference to the orientation and flexibility of the notochord, the rigid axial support that predates the formation of the vertebral column developmentally in chordate species. Pre-flexion larval fish have a notochord that is incapable of movement required for locomotion and foraging. Larval fish in this preliminary substage rely on a yolk sack provided for them in their early ontogeny. Flexion, or the development of flexibility of the notochord occurs at roughly the same time the yolk sack is depleted. This is a ‘critical period’ where the larval fish must find food within a short period of time, or the ichthyoplankton will not survive! Thus, the temporal and spatial distribution of ichthyoplankton in the water column is a crucial determinant of their survival. This guy is very lucky for having survived to this stage! Let’s all give him a round of applause.

We hope this was an informative and fun view into some of the many awesome critters found by ISIIS and our citizen scientists. Until next time!

Plankton Portal

A Zooniverse project blog

Monthly Archives: November 2013

From the citizen scientists: #FFF

Arrow worms: voracious plankton predators

Jellyfish blooms, Norway and Periphylla

Fantastic Find Friday: Back to Basics