Ecosystem Discussion

Coral reef ecosystems are some of the most diverse areas on our planet. The complex interactions that maintain the reefs are unknown elsewhere on our planet. Predation, competition, and various forms of symbiosis can all be found in the same place.  Furthermore, the kinds of symbiosis that exist are unparalleled terrestrially. The most obvious form of symbiosis comes from the zooxanthellae that live in many organisms, from corals to clams, from jellyfish to anemones. Their beautiful mutualism with thier hosts are some of the most colorful in the ocean.

Another form of symbiosis is the cleaning stations available on the reefs. Fish such as cleaner wrasses undulate their bodies for fish to come near so they can pick the ectoparasites from their scales. Cleaner shrimp also help to run these stations. Funny is that fish that would normally eat these crustaceans relax and just enjoy the cleaning without harming their detailers. 

 Another more common mutualism known to the public is the infamous clownfish-anemone relationship. Fish protect and clean the anemone, the anemone provides a safe haven for the fish.

Predation is probably one of the more common seen interaction of animals on the reef. But as I do my research on the crown of thorns starfish, the coral eating echinoderm, I've discovered a new predator of our poisonous friend.  Normally when on the GBR, it is not uncommon to see COTS munching down on some coral ledges, but what if coral started munching back? Well that's exactly what the anemone lookalike, pseudocorynactis does. The stony coral commonly lives in the crevices of reefs formed by other corals, a common favorite lounging spot of COTS. Though this coral is limited in its range in the Indian ocean, it has commonly been observed consuming COTS. Why this is not well documented could be due to its favoring of hard to find hiding spots. But one things for sure, if pseudocorynactis range were to increase, COTS might need to be on the look out!

[Left) Crown-of-thorns sea star Acanthaster planci eating coral; Middle) Corallimorpharian polyp attacks a crown-of-thorns sea star; Right) Paracorynactis hoplites ]

Killer clams

As I read my assignment for my marine ecology class, a chapter on coral reefs, I start to picture the Great Barrier before me. I was upset when the textbook referred to members of  Tridacna as "killer clams"...these things have honestly never aggresively killed anyone, they're not gonna jump up and attack you. Really. With the way science has progressed,  I figure nothing of such absurdity would even be published in a textbook.  Personally, I love the members of the genus Tridacna. They're gentle giants in my opinion, most unable to close their shell all the way. Their symbiosis with zooxanthellae produce some of the most gorgeous mantles I have ever seen. I love to stare at them for hours, mesmerized by their colors and patterns. Seeing my first blue lipped clam inspired me for life. Even though as a child I loved playing with garden snails (weird, I know), marine molluscs fascinate me on a whole other level. Their resilience, behavior, and diversity astound me. Most terrestrial mollusks are grazers. But with marine species, there's carnivores, omnivores, and herbivores. From the sea star-eatting triton snail to the suspension feeding clam, the diversity is amazing. From swimming slugs to floating snails and giant clams over a meter in length settled on the floor, their behaviors and morphology are unlike any other phylum of marine invertebrate. (The only others that come close are maybe are arthropods.) These will truly be my favorite creature to study and photograph while on the GBR, except for maybe the corals and other cnidarians.

Corals, damsels, and sea stars

First off, I am amazed at the ability of corals of the same species to spawn all at the same time. For animals with no brains, they never cease to amaze me in their behavior and lifestyles. As I read more about corals in my Marine Ecology class, I understand the importance of their relationship with their symbiotic algae, the zooxanthellae. Their coexistence is important in all aspects of both organisms, from nutrition, to protection, down to just plain appearance.  They really are connected creatures.

Damsels becoming more and more some of my favorite fish. from the way they aggregate to their colors and colonizations around reefs. I remember listening to a research presentation by Dr. Fuiman about mortality of damsel fish on patch reefs. The goal of his research was to determine which behavioral traits determine the survival and mortality after settlement of coral reef fish. His hypothesis focused on how escape performance of fish determines the survival of newly settled reef fish. In the end, the swimming behavior and the boldness of the fish determined their survival. I found all of it quite interesting and never thought about the behavior of such small fish, nevertheless how bold they were. 

With our essays in the works, I've decided to focus mine on the sea star, A. planci, or as we know them, the decimating crown of thorns starfish. Their abundance and negative effects on coral reefs is just horrible. I knew urchins could destroy entire kelp forests, but at least they have more predators. A. planci, with few predators past the larval stage, are much more nuisance than community neighbor. But more on their effects to come!

Discussion 3

As beautiful and fascinating as all the reef fish are, my favorite reef creatures are the invertebrates. Some of the simplest of the animals on this planet are one of the most complex living and beautiful organisms. Nudibranchs, top snails, anemones, and christmas tree worms are some of my favorites. As I stated in my previous blog, I love giant clams very much also. Another invertebrate I hope to see on our trip and actively identify are crinoids. Specifically the lovely, feather stars that perch themselves on corals for display!

Echinoderms, another interesting class of invertebrates that are exclusively marine, are some of the most fascinating, weird and destructive organisms on a reef. In California, urchins are known of their destruction of kelp forests but are luckily kept in check my otters. But on a reef, the crown of thorns starfish have few predators that stand a chance against their venomous spines. Luckily, there exists one effective predator against this decimater of reef systems, the Triton snail, largest of the gastropods! Though the spiny nemesis has its poison, this snail is immune to its venom and can tear the star to pieces with its radula. To see such a sport would be amazing but I highly doubt such a spectacle will occur.
Another notorious echinoderm is the sea cucumber, and by notorious, I mean for spilling its guts. This might actually be a sight possible while on the island, as they tend to spew their respiratory organs when threatened by pesky divers and other predators.

These are only some of the few invertebrates I hope to encounter while on the GBR. More species of interest to come!

My first post

This is my first blog post ever. Well to start off I am more than excited about this trip and with the way school is going, I wish it was already May. This will be my second trip to Australia, a once in a lifetime adventure that I get to return to. My first trip was amazing and what committed me to becoming a marine biologist. When you're out on the Great Barrier Reef, its like being in a whole other world. My experience went like this: the tide was low so we couldn't go over the reef but go around it, the water was terribly cold due to their winter weather, my legs were cramped and numb from kicking to stay. To this day, that was still the most amazing experience of my life...

 

To be honest, this is probably where I fell in love with giant clams. Mind you I have always had a deep love for molluscs, but giant clams were just amazing to see in the wild. I also have a crazy love of Cnidarians, so seeing all those lovely corals and anemones left me breathless. Note that all of these photos are taken with a Kodak water sport camera, I probably got the best underwater photos of all my friend who all bought fancy housing for their cameras before they left. The only down side was I had to keep swimming back down to take a photo, trying vigorously to not float up. I still can't figure out if that is a feather star or a Crinoid in my last picture attached to the coral...

This upcoming trip is the most amazing opportunity for me because it involves everything I love all in one course credited trip. I look forward to seeing the Reef again in a whole other environment, to swim over giant clams, chase butterfly fish, and take as many more photos as possible.  From the tiniest polyps to the largest of clams, this trip will be worth every second and cent.