Friday, March 6, 2015

The Amazing Sponges - Glue of the Reef



Orange Mycale armata sponge commonly found around Moku o Lo'e.
Photo taken by the Bishop Museum.



Sponges have been on our mind the past few weeks thanks to the newest visitor in the Jokiel lab, Dr. Janie Wulff from Florida State University.  After having the privilege to learn from her about her extensive sponge research, we decided to spruce up our own marine life post on sponges with the information we know now.
Sponge pore-bearing structure.
As mentioned in our previous sponge posts, they are quite fascinating creatures.  Belonging to the phylum, Porifera, they are named for their network of pores and channels through which they filter feed. As a defense, they possess spiny spicules that vary in shape but can be sharp and may help deliver the many toxins that sponges tend to produce.  The multicellular masses of sponge have the ability to morph and alter themselves due to unique cells that can transform to serve different purposes in the sponge anatomy.  These cells allow for quick healing of damaged tissue after being picked at by sponge-feeding fish.  Even fish that do not feed on sponges may approach eaten areas to pick at the newly exposed organisms that live in the sponge.  Many tiny critters seek protection in the small and deep pores of sponges.  However, these are just a few of the countless interactions sponges maintain with other marine organisms.


In addition to providing food and protection to numerous fish and invertebrates, they perform a number of services necessary for a coral reef to thrive.  Sponges help to stabilize coral colonies by growing through nooks and crannies at their base and affixing them to the reef creating additional support during times of increased wave action.  This also provides a barrier against organisms known for excavating into coral skeletons.  Sponges promote the reformation of corals following physical damage by gathering the leftover carbonate rubble from the broken skeletons and facilitating the reshaping of this carbonate through bioerosion, molding them back into the reef.

Orange Mycale sponge attacking a coral colony to the reef at Moku o Lo'e.
Photo taken by Mark Heckman

Despite their obvious plasticity in shape and size, and although they may look similar to each other, sponge species, like other marine animals, have variable growth rates and defenses particular to each environment in which they live which isolate them to specific marine ecosystems.  Dr. Janie Wulff tested habitat specificity of mangrove versus shallow reef sponges in Belize. Despite looking very similar at times, 78% of the sponge species  were only found in one location or the other, but not both suggesting a firm divide. By transplanting the most abundant sponge species in each habitat to the other habitat and observing interactions with spongivores and sponges naturally residing at each site, some interesting results came forward.  

Within 3 days of the experiment, 100% of all mangrove sponges transplanted to the shallow reef were consumed by predators.  The mangrove sponge species were unable to survive without protection from the mangrove roots. In turn, transplanted shallow reef sponges were quickly overgrown and out-competed by mangrove sponges due to their slower growth rates.  Mangrove trees are present in the shallow reef site normally, but less dense, allowing spongivores to access them easily and combat the rapid growth of the mangrove sponge species.  As a result, slowly growing reef sponges are not overtaken by the mangrove sponges in the shallow reef site.  It is clear that the sponge species in Belize, and probably on most tropical reefs have distinct characteristics allowing them to differentially thrive in specific habitats, which also boosts sponge diversity.

Photo taken by Candy Feller, Smithsonian Environmental Research Center
Tedani ignis, one of the mangrove sponges in Belize under study.
Photo taken by Candy Feller, Smithsonian Environmental Research Center 




In another study, mangrove sponges were removed from their native habitat and offered to grey angelfish and redband parrotfish for 12 days.  It was noted that the most quickly consumed sponges also had the fastest growth rates.  This suggests a possible relationship between growth rates and predator defense.  Perhaps for mangrove sponges in their protected habitat within the thick maze of mangrove roots,  faster growth rates are more important than slower growth and more complex chemical defenses against grazers, as are found in the open habitat shallow reef sponges.   However, more experimentation is required to look into this prospect.    




Unlike fish, invertebrates and corals, sponges are difficult to quantify and identify.  Thus, many scientists neglect to consider them in monitoring and assessment activities, giving us a lowered understanding of their importance.  In addition, past studies on interactions between sponges and reef fish have been questioned due to flawed scientific methods.  Dr. Janie Wulff is looking to use her own research to offset these weaknesses and provide a more realistic view of the role of sponges in reef ecology.  Her work has convinced many in the marine science community that routine surveying of sponges would prove valuable and should not be overlooked.  Healthy sponge populations are indicators of a thriving coral reef.  The poriferans have demonstrated their worth by cleaning the reef water (a basic sponge can filter up to 4 times its own volume every minute) and servicing the reefs in many other ways. In turn, we should do everything we can to ensure they remain there.

Sponges in Belize.  Photo taken by Florida State University.
 Written by Casey Ching and Mark Heckman

Bioerosion- The gradual removal or degradation of a material through action by an organism.

Wulff J (2005) Trade-offs in resistance to competitors and predators, and their effects on the diversity of tropical marine sponges. Journal of Animal Ecology. 74: 313-321. 
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2005.00925.x/epdf  Accessed 3-3-15. 

Wulff J (2006) Ecological interactions of marine sponges. Canadian Journal of Zoology. 84(2): 146-166.
 http://www.nrcresearchpress.com/doi/abs/10.1139/z06-019#.VPjasS4YmM6  Accessed 3-3-15.

Wulff J (2001) Assessing and monitoring coral reef sponges: why and how? Bulletin of Marine Science. 69(2): 831-846.
 http://www.ingentaconnect.com/content/umrsmas/bullmar/2001/00000069/00000002/art00046 Accessed 3-3-15.

Wulff J (1997) Parrotfish predation on cryptic sponges of Caribbean coral reefs. Marine Biology. 129(1): 41-52.
 http://link.springer.com/article/10.1007/s002270050144#page-1 Accessed 3-3-15. 

Friday, February 20, 2015

Cassiopea spp., the Upside-down Jellys




You may come across this unique cnidarian around Moku o Lo'e.  Cassiopea, also known as "upside-down sea jellies", are true to their name due to their unique nature of resting on the ocean floor with their bells face down and arms face up.  This positioning better exposes their undersides to allow their symbiotic alga  Symbiodinium spp. (zooxanthellae) harbored within their bodies to receive optimal exposure to sunlight, enhancing photosynthesis.







Upside-down jellies can be found throughout the Hawaiian islands in shallow lagoons on sand or mud bottoms or near mangrove patches. Like all of the cnidarians (the group that includes jellies, corals and sea anemones) they have special stinging cells, nematocysts,  in their tentacles allowing them to release toxic stings when threatened or to stun prey as needed.  When one jelly activates their nematocysts, it usually catalyzes the same response in surrounding jellies. As they are usually found grouped together, this can be a snorkeler's nightmare when one misplaced fin kick causes all the jellies to excrete mucus containing stinging cells in a chain reaction into surrounding water.  Obviously it is best to be the first snorkeler through the area!  Thankfully the sting is relatively mild, but still, when in the vicinity of upside-down jellies, it is in your best interests to be aware, proceed with caution, and be careful to leave them undisturbed.

Our local upside-down jellies were probably introduced to Hawaii around World War II. They most likely were released from various Navy or other ship's ballast water. With ships arriving here from around the world at that time, they could have come from virtually any ocean on the planet. Determining which species they are is surprisingly difficult. Almost all the Cassiopea worldwide look rather similar, and when they do vary in appearance, they do so across such a wide continuous range, that it is hard to say where one type lets off and another begins.

In Hawaii, scientists originally started by suggesting that we had a couple of different species, but uncertainty about the Cassiopea line led to them all being labeled as only one species, Cassiopea andromeda. Still, the high diversity of colors, shapes, and patterns among upside-down jellies in Hawaii sparked researchers to continue to question their classification.  The wide and beautiful range of appearances found near Moku o Lo'e are shown below.  




Photo credit - Casey Ching

Even two jellies with identical blue and white colorations, can be noticeably different in pattern and shape.  Such observations further supported the possibility that multiple species of Cassiopea may exist in the Hawaiian islands.  






Brenden Holland, Michael Dawson, Gerald Crow, and Dietrich Hofmann looked into phylogeography of the upside-down jellies on Oahu and observed two populations, one on the Windward side and one on the Leeward side.  They discovered these populations had variations in DNA as high as 20.3% - about what one might expect to find between two different species. When comparing the Hawaii jelly's genetics with those from around the world, the Cassiopea andromeda identified on the Leeward side has a genetic resemblance to those in the Red Sea and Atlantic Ocean. Less is known about the Cassiopea pinpointed on the Windward side, but genetic data supports connections to populations in or near Papua New Guinea. The authors referred to it as Cassiopea species #3. So it appears that there were two separate introductions of two types (species) of very similar looking Cassiopea jellies; a rare event among most organisms.  

Ever wonder where corals, sea jellies and anemones get their zooxanthellae from? They can be passed down from parent to offspring (vertical distribution) or they can get them from the surrounding environment (horizontal distribution). Not all zooxanthellae are quite the same, there are a number of different clades of zooxanthellae (genetically distinct populations - see below) that have different characteristics, which may make them better or worse partners for their host.

A number of studies have been done to determine which species of zooxanthellae naturally reside within each coral, jelly or anemone through vertical symbiont acquisition (transmittal from parent to offspring).  However when Dr. Ruth Gates collaborated with Michael Stat and Emily Morris to determine which zooxanthellae are obtained through horizontal symbiont acquisition (transmittal from the surrounding environment), for the local Cassiopea there were some surprises.  They found that some horizontally transmitted zooxanthellae formed a parasitic, rather than mutualistic, relationship. Signs of the parasitic relationship included diminished growth rates of the Cassiopea and an increase in densities of the invading zooxanthellae. In Hawaii, this could be attributed to Cassiopea themselves having invaded from somewhere else, they are just not set up for some of the Hawaiian varieties of zooxanthellae.  

Acropora cytherea shown above.


Likewise, species of zooxanthellae introduced by Cassiopea form uncommon relationships with other hosts as well.  At Papahanaumokuakea, an unusual symbiont was discovered on the stony coral, Acropora cytherea.  Upon further analysis, this symbiont was traced back to Cassiopea and its introduction to Hawaii's waters through ballast water discharge from ships.  

             
   


 Despite their invasion, we can't help but awe over their beautiful lacy patterns and diverse coloration.  On Moku o Lo'e, we're known to have particularly exquisite populations.  In the past, HIMB has been sought out to collect upside-down jellies from our waters for aquarium displays.  Currently, an impressive grouping of our jellies are exhibited in Monterey Bay Aquarium.     

Cassiopea on display at Monterey Bay Aquarium, possibly form the ones that were sent from HIMB.

Written by Casey Ching and Mark Heckman

Clade - A sorting of organisms that groups individual species together based on ancestral lineages.  It demonstrates common characteristics with recent ancestors and less shared characteristics with distant ancestors, showing the degree of relationship between species.

Monterey Bay Aquarium Animal Guide:

Holland B, Dawson M, Crow G, Hofmann D (2004) Global phylogeography of Cassiopea (Scyphozoa: Rhizostomeae): molecular evidence for cryptic species and multiple invasions of the Hawaiian Islands. Marine Biology. 145: 1119-1128.
http://www2.hawaii.edu/~trsnlab/image/papers/Holland_et_al_04.pdf  Accessed 2/12/15.

Stat M, Morris E, Gates R (2008) Functional diversity in coral-dinoflagellate symbiosis. PNAS. 105(27): 9256-9261.  

Stat M, Gates R (2007) Vectored introductions of marine endosymbiotic dinoflagellates into Hawaii. Biological Invasions. 10(4): 579-583. 

Wednesday, February 11, 2015

How Do You Do, from our new CEP Intern, Thomas Wood

Myself working on new teaching resources.
Photo taken by Casey Ching 
Hello everyone and it is a pleasure to meet you,

It may be obvious from the pictures, but I'm not from around here, so let me take a moment to introduce myself. I'm Thomas Wood, a new intern/volunteer here at HIMB through the Institute of Global Studies Programme for roughly the next 3 months. Hawaii is a 10 hour time difference and over 7,250 miles away from my home in jolly old England. Being an born, raised and a proud Englishman, experiencing Hawaii has always been a dream of mine, and I feel privileged to have the opportunity to be here on the island, let alone at this wonderful facility.

I spent four years at the University of Plymouth, studying and achieving a BSc (Hons) Geography, followed up with an MSc Applied Marine Science. I graduated in September 2014 and during my time studying for my MSc, I helped be a key part of the development of a local American Football Team, Torbay Trojans. Yes! It is a massively growing sport in the UK! I also had the opportunity to climb Mt Kilimanjaro for charity for the Meningitis Research Foundation as a nice side project.

Coral reef monitoring. Photo taken by Casey Ching
HIMB was a common talking point throughout my time at university in England, mainly due to the studies that have come out from this Institute. Therefore, I feel blessed to have the opportunity to be here and learning from some of the best names in the marine science field. I am still discovering what I want to do next, but undertaking a Ph.D. (hopefully in marine conservation) and then teaching at a university is definitely something which I have a keen interest in.

Hawaii and its beautiful culture, history and scenery is something I am enjoying, but I am also intrigued to experience Hawaii's marine culture and how it is conserved, stewarded, and will be kept by future generations. I hope to hone in on specific aspects that stimulate my own learning and that I can utilize in the future. During my time here, Mark, Casey and the volunteers, will entrust me to learn, experience and then lead educational tours of the Hawaii Institute of Marine Biology to a plethora of visitors and hopefully inspire future generations of marine scientists.

Still working hard on making the best resources
for future visitors and hopefully for you!
Photo taken by Casey Ching.
In my short time here, so far of just over 3 weeks, I have already helped with a couple tours, including assisting on a truly memorable cultural group from Le Fetuao Samoan Language Centre, followed by my first tour to a group of study abroad students from China. But wait, there's more! My Superbowl weekend was first spent aiding Leon with a brilliant Girl Scout Troop overnight, teaching them about night plankton and the different wavelengths of visible light to which plankton are variably attracted to. Don't fret though, the overnight ended in time so that I still managed to catch the game.

I am really grateful to everyone here for being so welcoming and giving me the opportunity to be a part of HIMB, surrounded by excellent staff, volunteers and faculty. I also would like to thank Dr David Adams at the Institute of Global Studies for also allowing me to do this once in a lifetime experience.

Have a brilliant weekend, and I look forward to hopefully seeing you all soon!

Aloha

Thomas

Friday, January 30, 2015

Eagle Project and Flatworms

Today's blog covers a couple of seemingly different topics but such is life here at HIMB. First off, we're always grateful to those willing to help us improve our island and its facilities!

Over the weekend, Eric Compton and his Scout Troop dedicated their time to installing gutters outside the Gates Wet Lab area.  Using donated materials from Hardware Hawaii and Home Depot, they constructed this mechanism for redirecting water from the lab, which frequently endures heavy rains and flooding.

                           
Photos taken by Leon Weaver

We need all the help we can get when it comes to preventing excess water from invading our research facilities!  Plus, this facility houses a state of the art research area where ocean acidification simulations can be set up and run to help understand changes on coral reefs. By cleaning up the outside, visitors are more likely to stop by and appreciate the cutting edge science inside. Check out Dr. Ruth Gates Lab facilities.

A few nights ago, Leon came across an amazing flatworm -  Pseudobiceros gratus!  This large (1.5") flatworm is characterized by its bold black or dark brown stripe down the middle of its back, distinct black ring and outline along its edges.  Leon witnessed it swimming through the water where it was suddenly seized by a glass anemone (Aiptasia sp.), but he was able to pry it out of the tentacles.

Pseudobiceros gratus flatworm. Leon Weaver image

Flatworms are often mistaken for nudibranchs, aka, sea slugs...

 Dendronotus fumata sea slug. Mark Heckman image

Nudibranchs which means,"naked gill," are in the snail family - they are essentially a shell-less snail, like land slugs. Like other sea snails, they have gills. In the case of the nudibranchs, they have a flower like plume of gills on the back of their body (as can be seen above). They also have two tentacles (rhinophores) up front to sense/smell the water. They glide along the bottom on their muscular foot and some even swim as needed.

The confusion comes when watching a similarly sized flatworm, often brightly colored, with two nuchal tentacles near the front end, gliding along or even swimming like a nudibranch mollusc. But it is not a mollusc - it is a flatworm - just a very large and impressive one.

The following video is a nice depiction of a flatworm swimming mid-water column:

  
Flatworm Video by Zoneku

However, as alike as flatworms and nudibranchs may appear, their relationship mostly ends with being in the Kingdom Animalia.  As human beings, we are programmed to link organisms with similar visual characteristics to other organisms with the same visual traits.  Thankfully, science helps us look more closely to better understand the world around us.

Aloha,
Casey

Friday, January 16, 2015

Entertaining video on CO2 rise and photosynthetic bacteria from SOEST

I learned about plants and photosynthesis in grade school (many many many many years ago). In college I learned about phyto-plankton - single celled plant plankton in the ocean (many many many years ago). Then I learned that the plankton in the ocean created (cycled) about 1/2 of the oxygen on the plante (many years ago).

The fact that photosynthetic bacteria are doing most of this work is slightly more recent and still very cool to me. Go microbes!

Check out this video from our parent department: SOEST at UH - This video was submitted into the Ocean180 Film Challenge. For more information on this, see: 

Aloha, Mark

Friday, January 2, 2015

Glass Anemones

In recent months, our water tables have started to succumb to an ever-frustrating anemone infestation.  Glass anemones, Aiptasia pulchella, found their way into our systems and large buildups occur if we do not remove them regularly.  They are known to be strongly disliked by aquarists because they sting corals and invertebrates in their closed environments.

When Aiptasia settle onto a substrate, they can easily come into contact with the other organisms nearby.  The anemones possess stinging cells called nematocysts that reside within the tentacles.  The nematocysts cause tissue damage to areas of the corals that they attack.  A few of ours have already fallen victim to their stings and were removed to other tanks to avoid further damage.

Aiptasia in our education water table
Taken by Casey Ching

Although we aren't happy about their presence in our tanks, these anemones, in their proper habitat are wonderful creatures and have many similarities to corals. Like reef building corals, their skin is largely transparent. The brown color comes from harboring algal zooxanthellae, a thin layer of symbiotic algae.  The zooxanthellae algae get a safe place to live and since they are able to photosynthesize, they take the waste products of the Aiptasia and produce extra sugars, fats and oxygen for the anemone.  This relationship is very similar to what happens in reef building corals, with one significant difference, corals are strongly dependent on this algae and will die without it, while Aiptasia do fine with or without.  

Because of this, Aiptasia are widely used on studies regarding zooxanthellae because they react similarly to reef building corals without the detrimental effects.  Dr. Ruth Gates worked in collaboration with UCLA to determine the effects of heat stress on Aiptasia pulchella and found that they reacted similarly to the reef building coral Pocillopora damicornis (lace coral) under the same conditions.  When exposed to raised temperature conditions, cells with the zooxanthellae attached to them would detach from within the anemone and be expelled producing the bleached look that is prominent among corals under stress.  We have both lace coral and Aiptasia in our tanks.

An example of bleached Aiptasia pulchella
Taken by AUS photography
 
To counteract the harm during bleaching events, HIMB researcher Robert Kinzie tested the adaptive bleaching hypothesis with multiple zooxanthellae-using organisms, one of which were Aiptasia.  He found supporting evidence that different types of zooxanthellae respond differently to various stressors and other types of zooxanthellae can be acquired from the environment once the original symbionts die off from the host.

Despite the bleaching events we've had in Kane'ohe Bay due to our recent temperature anomalies, studies have demonstrated that there's always the possibility of a recovery.  We may not like these Aiptasia in our tanks, but we appreciate the contributions they make to science.

Written by Casey Ching

References
Gates R, Baghdasarian G, Muscatine L (1992) Temperature stress causes host cell detachment in symbiotic cnidarians: Implications for coral bleaching. Biol Bull. 182:325-332.

Kinziee R, III, Takayama M, Santos S, Coffroth M (2001) The adaptive bleaching hypothesis: Experimental tests of critical assumptions. Biol Bull. 200:51-58.
http://www.biolbull.org/content/199/3/278.full.pdf. Accessed 12/24/14.

NOAA Ocean Service Education. Coral and zooxanthellae relationship. http://oceanservice.noaa.gov/education/kits/corals/media/supp_coral01b.html.  http://oceanservice.noaa.gov/education/kits/corals/coral02_zooxanthellae.html. http://oceanservice.noaa.gov/education/kits/corals/media/supp_coral02bc.html. Accessed 01/02/15.


Friday, December 19, 2014

Holiday Greetings and Year End Notes

It has been a great year thanks to all our staff, volunteers, students, teachers and visitors!

Every tour or lab we give is really an opportunity for all of us to learn from each other.  We learn history from those that have been here in the years before; stories of growing up in Kane'ohe and visiting the island in times gone by. Each student brings a new vision to our labs and tours. They find new animals we have not noticed in the plankton before, discover marine life behaviors we have never seen, and ask us questions that we can not answer, stretching our minds and keeping our brains in top shape.

Moku o Lo'e pulls the best from all of us.

Some statistics to think about,
In the past year our program hosted 4,722 visitors to Moku o Lo'e. We reached another 3,602 through community fairs and events and thousands more through this blog and other media outreach.
  
Visitors included 2,395 5th grade - college level students as well as 253 teachers in teacher workshops. 2,142 visitors were here as families or with community groups, and the program serviced an additional 414 VIPs, government or management related visitors.

Our volunteers contributed over 3,700 hours of their time and ran over 310 tours and programs mornings, afternoons and evenings, weekdays and weekends throughout the year. The students, children and adults whose lives they touched will not soon forget their visit to Moku o Lo'e.

In this time of giving, if you feel overwhelmed by all of the material buying and spending, think for a moment of those volunteer hours and be comforted. The true giving season is really all year long. And yes, our volunteers have asked if there are tours to help with over the holidays, it does not stop.

With Aloha,

Mark