Recent Discovery of Giant Shipworm Kuphus polythalamia's Unique Feeding Strategy

Kuphus polythalamia is a type of bivalve called a "shipworm" (although K. polythalamia is not a worm, nor does it live on a ship).  It is a member of the family Teredinidae. Shipworms are elongate, and have rasp-like shells for burrowing into wood. Kuphus polythalamia is unusual because of its large size.  It can reach up to five feet long and grow to almost two and a half inches in diameter.

Kuphus polythalamia  has been known of for a long time, due to the frequent discovery of their elephant tusk-like shells since the 1700s. However, the animal itself was usually long since dead and decomposed and had never been studied. Since its shells were usually dragged up in nets by fishermen, it was hard for scientists to pinpoint the exact habitat where it lived. By chance, a documentary filmed in the Phillipines showed it burrowed into the sediment of a lagoon. A team of scientists launched an expedition to that location, and brought back specimens.

They found that, unlike other shipworms, which feed on wood, which they are able to digest because of symbiotic bacteria that produce digestive enzymes to break down the wood (allowing the bacteria, in return, to obtain organic carbon from their shipworm host), Kuphus polythalamia does not eat wood.  Its digestive organs have shrunk, and it spends most of its time encased in its closed up shell, without taking in any wood.  Instead, it relies on a chemotrophic feeding strategy, meaning that it metabolises chemicals instead of sunlight (autotrophs) or organic matter (heterotrophs). Most shipworms are heterotrophic.

The way this works for Kuphus polythalamia is that it has bacteria, which live in its gills, and  metabolize sulfur. In doing this, the bacteria create organic carbon, which Kuphus polythalamia feeds on.  This is the different from the usual shipworm mutualistic symbiotic relationship.  Kuphus polythalamia's symbiotic partner bacteria do not rely on it for food.  Instead, they provide it with food by breaking down sulfur based environmental compounds that come from rotting wood in the area.  (The lagoon where Kuphus polythalamia was found had been used as a log storage pond.)

It has been hypothesized that the way this trait evolved was that Kuphus polythalamia's ancestors fed on wood, specifically wet, rotting wood, which released sulfur. They shared the enviroment with chemotrophic bacteria, and somehow, the chemotrophic bacteria got stuck in their gills. Instead of dying, the bacteria thrived, and as a byproduct of their chemosynthesis, they manufactured organic carbon, which is benificial for shipworms. This feature allowed these individuals to survive better than those without the bacteria, and for them to exploit new habitats, such as the muddy bottom of a lagoon. Eventually, they evolved into a seperate species, Kuphus polythalamia.

SOURCES:

Kuphus polythalamia: Marine Biologists Study Giant Mud-Dwelling Shipworm for First Time, Science News (April 18 2017.) Published online at    http://www.sci-news.com/biology/kuphus-polythalamia-giant-mud-dwelling-shipworm-04789.html?fbclid=IwAR3fxZweBBuujpO6eO3emt3xxHqrLv3UtBP_nfTLPibCF04NhBn_oTDmis8

Kish, Stacy W., Science Fiction Horror Wriggles Into Reality with Discovery of Giant Sulfur-Powered Shipworm (April 17 2017.)  Published online at https://healthcare.utah.edu/publicaffairs/news/2017/04/shipworm.php?fbclid=IwAR2ZHz1Ugxpz05o5Kxv0SwF_HRYYoCe0USWL3t_FvB66SbEGGN7MV1HsSH4

Daniel L. Distel, Marvin A. Altamia, et al, Discovery of Chemoautotrophic Symbiosis in the Giant Shipworm Kuphus polythalamia (Bivalvia: Teredinidae) Extends Wooden-Steps Theory, Proceedings of the National Academy of Sciences Apr 2017, 201620470.  Published online at https://www.pnas.org/content/early/2017/04/13/1620470114.full

West Indian Fighting Conchs

The West Indian Fighting Conch is the animal I picked for my project this week.  My mom had a conch shell on her desk when I was little, and I was curious about it, so I decided to learn more about conchs.

Taxonomy:
Kingdom Animalia
Phylum Mollusca
Class Gastropoda
Family Strombidae
Genus Strombus
Species pugilis.

Common name: West Indian Fighting Conch.

The West Indian Fighting Conch's maximum length is approximately 110 millimeters, though the average length is more like 90 mm.   Its range stretches from Florida across the Caribbean and all the way down to Brazil. It lives in the intertidal zone and in shallow water up to 10m generally.

It is dioecious, meaning individuals are either male or female.  Another word for this is gonochoric.  West Indian Fighting Conchs have external fertilization.

The conch starts off as a fertilized egg, which divides and becomes a meroplanktonic trochophore larva. Later it moves on to the veliger larval stage. It eventually settles down and start growing its shell. It spends this time burrowed under the sand to avoid predators.  After about four years, the conch is an adult.  It emerges from under the sand, and the cycle continues.

West Indian Fighting Conchs are herbivores, feeding on algae and other plants.
One of their predators is Octopus maya or the Mexican Four-Eyed Octopus. It has neurotoxins which can paralyze its prey, while it drills into the conch's shell.
Another predator is Homo sapiens, who usually cook their prey.  In the Florida Keys, conch fritters are a common dish.

Cool facts:

Key West calls itself "the Conch Republic" and has a conch depicted on its flag.

The reason they are called "fighting conchs" is because if you pick one up, it will jab at you with its sharp, sickle shaped operculum!

Human hunting of conchs is likely driving them to evolve to be smaller so they are less attractive prey.  This is an interesting article about it: humans affect conch evolution article.

HHMI Biointeractive Lab on Sorting Seashells.

The HHMI Lab on Sorting (i.e. classifying) Seashells was really interesting and fun.  Here is the worksheet I did as part of my assignment:

Model of a Chiton

Chitons are marine mollusks in the Class Polyplacophora.  They live in the intertidal and subtidal zones.  They all have eight armored plates on their dorsal side for protection from predators.  They can roll up into a ball when disturbed, like pill bugs do.  Their armored plates are surrounded by a soft girdle.  They have a muscular foot that they use for locomtion.

Chitons have gills for respiration which are located on their ventral side, underneath the mantle (a layer of tissue between the shell and the visceral mass), and surrounding the foot.  They have a mouth, which contains the radula, a raspy organ that they use to scrape the algae that they eat off of rocks.  They also have an anus.  They have a heart and an aorta.  Their nervous system includes a nerve ring that surrounds the mouth.  They have  primitive eyes that are part of their shell and see only pixellated images.

They are dioecious, i.e., individuals are either male or female.  The chiton's trochophore larvae  are lecithotrophic, which means "feeding on yolk". They do not go through a veliger larval stage.  Instead, they feed on their egg yolk,  growing bigger over time. They eventually fully absorb the yolk, and become adults.

One medium sized tropical species, Acanthopleura granulata, commonly known as the West Indian Fuzzy Chiton, lives in an area that stretches from Southern Florida to Panama, in the Carribean Sea. It has spines on its girdle that give it a fuzzy look, and perhaps deter predators.   It inhabits the intertidal zone, where it eats algae.

One adaptation it has is a rhythymic pattern of movement that allows it to withstand storms and rough seas.

Hamilton (1903), for example, observed a rhythmic movement of the girdle of Acanthopleura in phase with the wave period. The girdle was brought flush and tight against the substratum with each approaching wave and then was raised during the backwash. 

Peter W. Glynn, On the Ecology of the Caribbean Chitons Acanthopleura granulata Gmelin and Chiton tuberculatus Linne: Density, Mortality, Feeding, Reproduction, and Growth, SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY NUMBER 66, SMITHSONIAN INSTITUTION PRESS,  (Washington D.C., 1970), at p.5.

Another adaptation it has is the ability to tolerate a lot of sun and exposure without drying out.  (See Glynn at p. 18.)  They also exhibit "homing." that is, they move at night to feed, but return to the same area during their less active daytime hours.  (Glynn at p.7)

Their primary predators are sea stars, crabs and other crustaceans, rats, and birds.

I built a model of a chiton using aluminum tape and a large rubber band.  The plates slide to allow it to roll up.

Here is a video that shows me unrolling it.  It didn't work as smoothly as I would have liked.

Flatworms, Nematodes, Annelids and Bristle Worms

This assignment was to create a project showing the 3 types of worms we learned about: Platyhelminthes (flat worms), Nematodes (round worms) and Annelids (segmented worms) (including Polychaetes, or Bristle Worms.

All three types of marine worms have bilateral symmetry and triploblasty (three cell layers: endoderm, mesoderm and ectoderm.)

I created models of each using Tinkercad Software.

This is the flatworm, or platyhelminthes:

Flatworms have a flat body plan, a simple brain called a ganglia at their head end, eyespots that can sense light and dark,  and nerve chords that tell their muscles how to move.  They have only one opening at the end of their pharynx (a tube connecting the gut to the sole opening in their digestive tract, which serves as both mouth and anus.)  The gut spreads throughout the body.

This is a round worm, or nematode:

Round worms have a round cross section.  Thir bodies are smooth and not segmented.  They have two openings in their digestive tract, i.e. a separate mouth and anus.  

This is a segmented worm, or annelid.  It is from Class Polychaeta (a bristleworm).

Annelids have round segmented bodies.  They have well developed digestive, nervous and circulatory systems. They breathe through their skin.

The creature that I modelled is a Polychaete, or "Bristle worm."  It is an annelid that has stiff hairs or setae attached to its body by paddle-like structures called parapodia.

Here is a video of me explaining the models:

Cladogram worksheet

Sorry for the bad handwriting.  This is why I normally type assignments up...  Just in case, I will retype the answers below...

1. Multicellularity.

2. Scyphozoa and cubozoa.  They are on their own branch.

3. No, only scleractinians.  Because calcium carbonate production appears at the scleractinia branch.

4. Rhopalium.

5. Anthozoa.  The polyp body form as an adult is what separates class anthozoa, so all the orders within anthozoa have it.

6. Tissues. Nematocysts.

Scyphozoans and Cubozoans Compared, Using 3D Models

For this project, I created 3D models of a True Jellyfish (scyphozoan) and a Box Jellyfish (cubozoan) using Tinkercad software.

The True Jellyfish (Scyphozoan) has a medusa body plan.  It has a round bell, tentacles attached at the margin or edge of the bell, and oral arms attached further in surrounding the mouth.  It's gonads are the ring shaped structures in my model. It also has rhopalia, which are sense organs that can detect light and dark,  and up versus down.

The Box Jellyfish, or Cubozoan, has a somewhat different anatomy.  Its bell is square when viewed from top or bottom. Its tentacles are attached to the corners of the square by structures called pedalia.  There can be one tentacle, or many, attached to each pedalium.  Cubozoans also have sense organs called rhopalia, but theirs are more advanced than those of scyphozoans.  They have some rhopalia which actually look like an eye, though others are more simple.  In addition to light and dark and up/down, they can distinguish colors, although they do not seem to see white well.  They avoid things that are red.

Here is a video of me explaining the models:

Scleractinia 3D Model

This is a 3D model of scleractinia (hard coral) which I built using Tinkercad software.  Scleractina produce calcium carbonate skeletons, which is what coral reefs are built out of.  

Anatomical features are labelled in the first two images.  One polyp is shown with a cutaway of part of the corallite so the polyp and septa are more visible.

My model is an example of a scleractinia colony, showing two polyps.  Each polyp in an individual organism, but they live together in a colony.  

Corallites are the calcium carbonate skeletons that each polyp creates.  Each corallite has separate walls.  Inside the corallite there are ridges called septa.  Each septum is sandwiched between two layers of mesentery tissue, which secrete the calcium carbonate that forms the skeleton of the coral.

Polyps are joined together by a layer of living tissue called the the coenosarc, which covers the coenosteum (skeletal tissue which connects the corallites).

Here is a video of me showing the model in 3D:

Mushroom Corals: A Dichotomous Key for 3 Main Genera

1.
 A: If oral disk is smooth------------------------------------------------------Discosoma
 B: if oral disk is not smooth-------------------------------------------------2

2
A: If oral disk is covered with rounded, bumpy tentacles---------------Ricordea

B: If tentacles are not round, and there are many pseudotentacles------Rhodactis

Zooxanthellae/Coral Symbiosis

This diagram shows a section of a polyp, with zooxanthellae, and shows their symbiotic relationship. The coral will only grow in sunlit areas, so the zooxanthellae can photosynthesize. The coral provides protection with its tentacles, and carbon dioxide, a waste product for the polyp, but vital to the zooxanthellae for photosynthesis. The zooxanthellae, in return, give the coral oxygen, necessary for animal life, and nutrients, giving the coral nourishment when it cannot find prey.

Symbiosis and Anemones

1
  In the illustation below, you can see the anemone Adamsia sp. attached to the shell inhabited by the hermit crab Pagurus bernhardus. This is a mutualistic symbiotic relationship, as both parties benefit. The anemone gains the ability to move around, and find different prey options, instead of being stuck in one place, and the hermit crab gets protection from predators.

2

  A Lybia tesselata, or boxer crab, is shown in the illustration below holding the anemone Triactis producta in its claws. It appears to be a mutualistic relationship, as the anemone is only found with the boxer crab, but how the anemone benefits is unknown. Perhaps, as in the case above, it benefits from being carried to new sources of food by the crab.  On the other hand, the benefit to the crab is obvious, since its claws are far too small to be used for defense. So it instead keeps two smaller anemones, trimming them down to the right size, as "boxing gloves" for protection.

3
  The anemone below is  Anthopleura elegantissima, or aggregate anemone. At first glance it does not look like a symbiotic relationship is taking place, after all it is just a green sea anemone. However, the green coloration is caused by dinoflagellates and other phytoplankton, which release oxygen for the anemone. In return, the anemone grows in the photic zone so the algae have enough sunlight, and provides carbon dioxide, both of which are necessary for photosynthesis.

4
  A Stenorhynchus seticornis, or arrow crab, is commonly found living on Lebrunia neglecta (which also has a mutualistic relationship with algae), and this would seem to indicate some type of mutual relationship. This is not the case however. The arrow crab lives in the anemone's tentacles for protection, but does nothing for the anemone in return. This is called a commensalistic relationship, a type of symbiosis in which one member benefits, but neither aids or harms the other.

Marine Zoology Homework2: Contrast Porifera and Cnidarians

Differences Between Porifera and Cnidaria:

1. Porifera do not have specialized tissues.  Cnidaria do.

2. Porifera are sessile as adults.  Cnidaria vary.  Some are sessile as adults (e.g. anemones, corals), but some are planktonic as adults (e.g. jellyfish).

3. Porifera have hard skeletal elements called spicules.  Although corals build a hard exoskeleton, cnidaria do not have spicules.

4.  Cnidaria have powerful stinging cells called nematocysts.  Porifera do not.

5.  Cnidaria have tentacles.  Porifera do not.

6.  Porifera are asymmetrical.   Cnidaria have radial symmetry.

7.  Porifera have pores called ostia through which they take in water (and plankton), and an opening called an osculum through which filtered water is expelled.  Cnidaria do not have these structures.  They have a single opening that acts as both mouth and anus.

8.  Almost all sponges are filter feeders.  All cnidaria are predators.

9.  Porifera do not have any sort of a nervous system.  Cnidaria have a primitive response system.

10.  Their larvae are different.  Porifera have lavrae with long flagella.  Cnidarians have larvae with shorter cillia.

Marine Zoology: Invertebrates I Homework: Build a model of a sponge

For my Marine Zoology class homework, I had to build a model of a sponge.

I chose to build a 3D digital model using Tinkercad.  I had to label the various parts of the model.

Here are some screen shots of the model, and one that I altered to add labels,

Here is a video of me explaining the model.

.

Plankton Race: Marine Bio 101 Homework, Week 4, Part 2

For Marine Biology, I had to design a plankton which had adaptations for buoyancy and drag that we discussed in class and get it to take as long as possible to sink to the bottom of a tank of water.

The water had to be 12 inches deep.

The plankton could not be bigger than 3 inches long on its longest side.  Mine was about 2.5 inches long on its longest body side. 

The body was a sponge, which was a flat body plan.  The sponge had air pockets, an adaptation for buoyancy which some real plankton have.  It also had spikes made of bamboo skewers (another adaptation which increases buoyancy).

To test the design, you hold it in the water so it is just sumberged, then let go.  (You don't just drop it into the water.) 

It floated.

So I attached some flagella-like structures made of fishing line and beads.  I also added some screws to the sponge with a rubber band to give it some mass. 

It went straight to the bottom in less than 2 seconds. 

Next, I removed some beads and made the flagella shorter.  I figured that would cut down the drag a bit.

That helped it to sink somewhat slower. It took approximately 3 seconds.

It still needed something. 

Next, I attached a cloth parachute to it (a drag increasing adaptation, similar to the body plan of jellyfish). 

That slowed it down, but not enough.

I added streamers (less than 3 inches long) (also to increase drag.)  And then a second set of streamers.

Now it just sank.  Fast.

I cut the streamers shorter.  That helped a little bit, but not enough.

So next I added some vaseline to the bottom of the sponge to mimic lipid or fat pockets that some real plankton have.  This increased the buoyancy enough that my plankton slowly sank to the bottom of the tank. 

At this point, my parents helped me by timing it and shooting video.  Unfortunately, my mom's camera did something really weird, and it lost the audio of me explaining the project, so I am typing this up instead. 

It wouldn't download either, showing up as only a still photo, but it ran on mom's camera.  She used another camera to video the video so I could upload it.  Sorry if the video quality is not the best, but you can pretty much make out my dad's phone that he used as a timer. 

I did several tests of the final plankton.  The best time I had was 10.2 seconds, and the next best was 9.7 seconds. 

Marine Biology Homework: Plankton Project

My homework this week was to do a project on plankton.  I had to select 5 phytoplankton and 5 zooplankton and give the domain and kingdom each is classified under, and for the zooplankton, note whether the organism is holoplankton (remains plankton for its entire life) or meroplankton (is plankton for only part (the larval stage) of its life cycle.)

Here are the phytoplankton:

First, we have an organism called Stephanopyxis palmeriana, a Chain Forming Centric Diatom.  It is in the Domain Eukaryota, and Kingdom Chromista.

Next, we have Ceratium fusus, Ceratium tripos and Ceratium macroceros, which are Dinoflagellates, in Domain Eukaryota and Kingdom Protista:

These are Scyphosphaera apsteinii, which are Coccolithophores.  They are in Domain Eukaryota and Kingdom Protista:

This is Eucampia zodiacus.  It is a Chain Forming Centric Diatom (which forms spirals) and is in Domain Eukarota, Kingdom Protista:

This is a Centric Diatom, Rhizosolenia robusta.  It is in Domain Eukaryota, Kingdom Protista:

This is Pleurosigma sp., a Pennate Diatom, from Domain Eukaryota, Kingdom Protista.

The following organisms are zooplankton.

First, we have a Paddleworm, Tomopteris helgoandica, which is holoplankton from Domain Eukaryota, Kingdom Animalia:

Next we have Ophiothrix fragilis, the Common Brittlestar, which is meroplankton.  It is in Domain Eukaryota, Kingdom Animalia.

This is the Porcelain Crab, Pisida longicornis.  It is in Domain Eukayota, Kingdom Animalia.

This is the Sea Angel, Clione limacina.  It is holoplankton in Domain Eukaryota, Kingdom Animalia.

This is Acartia Clausi, a type of Copepod.  It is holoplankton in Domain Eukaryota, Kingdom Animalia.

Marine Biology Homework, Week 3: Marine Zonation

My assignment this week was to do a project which shows the location of the following marine zones: supratidal, intertidal, subtidal, benthic, pelagic, neritic, oceanic, photic, and aphotic.

I decided to do a three dimensional model of the zones on the computer, uising Tinkercad, which is shown below in screen captures.

The next part of the assignment was to identify an organism that lives in each of the above zonal habitats and to describe one adaptation it has for doing so:

SUPRATIDAL ZONE: Whelks inhabit the supratidal zone to a limited extent.  One adaptation they have is for coping with the scarcity of food there.  They have  a toxin called purpurin, which they inject into barnacles to cause them to open their shells.

INTERTIDAL ZONE: Several species of barnacle inhabit the intertidal zone. They have evolved an outer shell that can close while the tide is out, protecting the vulnerable crustacean within, or open when the tide is in allowing its legs to emerge for filter feeding.

SUBTIDAL ZONE: Sea anemones are firmly attatched to the seabed to avoid being swept away by waves and currents, they are filter feeders which allows them to take advantage of nutrients that are swept into the subtidal zone.

NERITIC ZONE:  The nautilus traps pockets of air in its shell to assist with bouyancy, and several species of fish use countershading to avoid predators.

OCEANIC ZONE: Dolphins have a streamlined body plan, allowing them to travel long distances through the water quickly.

PELAGIC ZONE:  The leatherback sea turtle travels long distances across the Pacific and Atlantic Oceans..They are adapted to this by eating jellyfish, a common group of pelagic organisms, in addition to having huge flippers to propel themselves through the water.

BENTHIC ZONE: Flounders have a sideways flattened body plan with one of the eyes migrating to the other side of its head during adolescence. This allows them to lie flat on trhe seafloor and cover their bodies with sand, both hiding them from predators and concealing them from prey.

PHOTIC ZONE:  Phytoplankton are adapted to  survive in the photic zone by using the available sunlight to engage in photosynthesis and make food.

APHOTIC ZONE:  Dragonfish have bioluminescent red patches under their eyes. the dragonfish can see the red light, but since no red light reaches the aphotic zone, the eyes of its prey are not adapted to see the color red. This can be used to illuminate the darkness for hunting, as well as to locate other members of their species for mating.