ISIIS in the field: OSTRICH cruise in progress

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).

OSTRICH logo

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.

postdoc ad sample images

Sample ISIIS images showing diversity of plankton from multiple coastal sites (including the Southern California Bight!)

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:

 

 

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From the citizen scientists: #FFF

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.

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[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.

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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.

51d1bdbb3ae74008a401f2ed[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.

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[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)

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[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

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Fantastic Find Friday: Back to Basics

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

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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

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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

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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

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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

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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!

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!

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Larval fish
http://talk.planktonportal.org/#/subjects/APK00015nq

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

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Liriope tetraphylla (#Medusae #4tentacles) with Arrow worm
http://talk.planktonportal.org/#/subjects/APK0000q5x

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.

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Sphaeronectes koellikeri – #rocketship #thimble
http://talk.planktonportal.org/#/subjects/APK00002cl

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!

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Radiolarian colony – #radiolarian #colony
http://talk.planktonportal.org/#/subjects/APK00003kq

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!