Ocean acidification (OA) may be one of the most challenging things to communicate to the public. In principle, OA is quite simple--the ocean becomes acidic as more carbon dioxide (CO2) dissolves in seawater. However, chemistry is not always a strong suit for everyone, and the more complicated aspects of carbonate chemistry in seawater can be lost on even the most scientifically minded lay person. (Don't worry--Woods Hole Oceanographic Institute is here to help!)  I've been looking around for helpful resources that explain OA to the public--some are videos, some are blogs-- but in each case they provide a different take on exactly what OA is. Perhaps more important, they discuss OA effects on different ecosystems and livelihoods. Click the images, videos, or embedded URLs to dive into some of the science and hot topics in OA research

As a coral biologist, I'm concerned with how amore acidic ocean will lead to the dissolution of coral reef architecture--the coral and the myriad of calcifying invertebrates that reside on reefs, as well as the sand and limestone that form the foundation of reefs. However, a more acidic sea can also reduce the SPEED at which calcified organism build their skeletons. This is because, like all things, we are at a constant fight against degradation, breakdown, entropy. As an animal builds its skeleton it is also slowly losing parts of its skeleton to processes of erosion--some biological (boring animals like sponges and gastropods), others physical (wave action, abrasion, breaking off). So, in order for animals and reefs to GROW, there must be a positive balance where growth (accretion) exceeds loss (erosion). Therefore, OA reducing this positive balance reduces the net calcified growth of an organism and in essence, they may be smaller for longer and not build skeletons as quickly. Finally, once the animal is dead and ceases to grow all together, more acidic conditions can lead to fast dissolution of the calcified material all together.  

Watch the education video (left) to learn more about what ocean acidification is. On the right, you can watch a TED Talk by Dr. Rob Dunbar on the threat of OA and the challenge we must confront as we address rising carbon dioxide in the atmosphere (leading to warming) and in the ocean (causing seawater acidification).

Changing ocean chemistry can affect coral reefs, but it can also affect commercial crops like mussels, oysters, and clams. Many *human* coastal communities across the world depend on resources from the sea. Decreases in yield or quality of products (smaller oysters, let's say) will hurt these communities, and therefore OA is not solely a tropical reef problem, but a global problem with implications at virtually every scale of marine life. 

Finally, I saw this blog this week from Rice University describing ocean acidification (OA). It is pretty nice, showing both the chemical basis of OA and some of the impacts OA can have on biological organisms.
When Air Meets Water: Carbon Dioxide And Ocean Acidification

For those wanting to get more information, the US National Oceanic and Atmospheric Administration is a worldwide authority. You can view real data from ocean monitoring stations and learn everything about OA from chemistry to biological and socio-economic impacts of OA
Learn about Ocean Acidification and OA research at NOAA and the NOAA PMEL Carbon Program

 This week, for the first time gravitational waves were confirmed to exist, confirming one of Einstein's most famous theories (1916): the theory of general relativity. These gravitational waves are ripples in space time--a concept by itself that forcibly elicits a "whoa" from even the most intelligent among us.  This discovery has been acclaimed as perhaps the most influential discovery of the last century, but what does it really mean?? And why am I talking about this--it has nothing to do with coral reefs?!  Well, yes, it really has nothing to do with corals, but it concern science, and who doesn't love a groundbreaking scientific discovery!

First, hurray for science--and tax dollar funded science at that! The two laboratories in the United States that made this discovery are funded through the National Science Foundation (NSF), which also funds countless other research programs ranging from the origins of the cosmos to anthropogenic climate change.  As a taxpayer, we should all take pride in the fact that we supported this fascinating scientific breakthrough.  This project took vision, and the continued support from NSF and the federal government made this discovery possible.  Further, the USA did not go it alone on this project, but was joined with collaborating nations the world over. Together, an international consortia of scientists, engineers, technicians, and students from diverse disciplines made this advancement possible. Cheers to collaborations and to standing on the shoulders of giants!

So how was this discovery made? Two Laser Interferometer Gravitational-wave Observatory (LIGO) facilities in Louisiana and Washington (as a part of the LIGO Scientific Collaboration) detected the merging of  two black holes (each being 2-3x the mass of our sun).  This cosmic explosion set off ripples in the form of gravitational waves that permeated through the cosmos -- and scientists were able to detect this galactic groundswell with stunning clarity.  The astounding part of this, as if the fact that black holes are no longer a think of theory or science fiction, was that this event occurred over 1 billion years ago! I haven't seen estimates of how fast this wave was traveling, but this should give you an idea of how massive the universe truly is.

​Below, listen to the "chirp" from behind the curtain of a 1 billion year old gravitational wave! 

​The executive director of LIGO at the California Institute of Technology gave the best description of this: "It’s the first time the universe has spoken to us in gravitational waves." Such an amazing statement.  This finding blows open a whole new field of astronomy (gravitational astronomy) and provides an new perspective to Einstein's century old theory.  A fundamental beauty of this discovery is the strength of the scientific method: new observations were made, new testable hypotheses were generated, and the data we've collected now can reinforce or augment the theory of general relativity.  It is a blessing that we have an empirical system such as science to help us understand the cosmos and our place within it.  Personally, I can't wait for a Neal deGrasse Tyson, the Sir David Attenborough of the cosmos, to give a lecture or podcast on this. TED talk--I'm speaking to you!
​

I'm not a physicist! But I can certainly appreciate how amazing this discovery is and how exciting it is to be alive in these times.  With all the bad publicity humanity receives, it is nice to hear of people and nations working together. Further, this should help us all see how minimal we are in the universe.  Put frankly, the fusion of these black holes occurred just after eukaryotic cells evolved on Earth (2.0-1.8 bya)! Yet, here I am writing about it on a computer that itself is an impossibility to my parent's generation. 

In closing: Science moves in leaps and bounds.  After a century of research and theorizing, in one day scientists were able to confirm (1) black holes can largely be accepted as real and no longer theoretical, (2) we can measure gravitational waves--and they exist!  However this discovery would not have been possible had we not laid the groundwork for the LIGO facility in the 1980s and the continued support of its research--including recent upgrades approved during the last decade.

The message here is really that science takes time and hard work can pay off!  Perhaps more importantly for you, me, and John Q. Public to realize is that this transformative discovery would not have been possible without federal funding, tax payer dollars, and the vision of scientists and legislators to appropriate funds towards projects that can move humanity forward. In this, there is a message for addressing climate change, energy independence, and the myriad of other problems facing humanity.

Where will this discover take us? I don't think anyone could say--but it may be safe to say that this advancement may be a game changer for the fields of astronomy, physics, quantum mechanics, and I'm exited for the future! Need more info?! Check out these links and videos!

References:
http://www.sciencemag.org/news/2016/02/we-did-it-voices-gravitational-wave-press-conference
http://www.nbcnews.com/id/24032470#.VsLAQ5MrKRt
https://www.ligo.caltech.edu/news/ligo20160211
http://www.usatoday.com/story/opinion/2016/02/12/ligo-discovery-impossible-without-public-funding-gravitational-waves-column/80253446/
http://www.nature.com/news/gravitational-waves-a-three-minute-guide-1.19366
https://www.youtube.com/watch?time_continue=3&v=KpnOe9JPEdY

After a long divorce, the relationship between Cuba and the United States (U.S.) is entering a new chapter.  The U.S.-Cuba trade embargo of 1962 has had large impacts on the Cuban economy.  However, Cuba's isolation and attenuated coastal development and tourism has reduced human impacts on Cuban coral reefs.  Additionally, the Cuban government has advocated significant marine resource protection dating back to the 1990s.  This protection appears to have made a difference, and today many of the most pristine Caribbean coral reefs are found in Cuba.  

​As the United States and Cuba once again open a diplomatic dialogue, what will this mean for the state of Cuba's coral reefs?  Will a normalizing of relationships between these two countries lead to reef degradation from coastal development, tourism, and overfishing, turning Cuba into its northern neighbor, Miami (no offense Miami...)?  Personally, I've heard a lot of buzz about this topic with marine scientists concerned with coral reef conservation, as well as laypeople wanting to "see the reefs of the past before they are gone (again?)."  ​ 
 
​Well, some encouraging news... The New York Times ("Cuba and U.S. Agree to Work Together to Protect Marine Life") report that government agencies in the United States and Cuba will coordinate on coral reef conservation and the study of marine life in protected areas within the Florida Strait and the Gulf of Mexico.  The agencies will be tasked with compiling shared ecosystem properties, species compositions, endangered species abundance, etc., among reef systems to better understand what makes Cuban reefs "unique."  At a time when human impacts on reefs are substantial, the world could learn valuable lessons on reef conservation by studying Cuba and its management of marine resources.  While intergovernmental collaboration may seem like a small step, remember that the relationship between these two Cold War enemies is complex, and any sign of thawing (get it, Cold War... thawing) is a harbinger of progress.  Finally, it is important for the United States and Cuba to learn to work together--in science and in politics.  Because while politically the two countries may remain polarized, science and conservation may serve as common ground for cooperation.

Corals are amazing organisms that have prospered in the shallow, nutrient poor seas of the tropical and subtropical oceans.  These animals, along with their symbiont algae have built the massive calcified structures and architechture that defines the ecosystems that bare their names.  Coral reefs are presented with many challenges in the Anthropocene--the epoch of man--and as coral ecologists we study how the physiology and genetics of corals change in response to changing environmental conditions; how corals are affected by disease and pathogens; and how the 3D structural nature of reefs (that is, the "rugosity" or architectural complexity of the reef structure) change through time due to biological and physical processes. 

In the Monument, the Coral Health Team has explored numerous reefs, ranging in depth from 3 ft to 60 ft on the backreef and forereef of these remote islands and atolls. Over this range of depths and locations (windward, leeward), and weather conditions, the reefs can be strikingly different!  At each location we assess a variety of ecological and physiological metrics, including:  disease prevalence, coral bleaching percentages, coral benthic cover and species composition, and we collect water samples and coral samples to study the physiological ecology and genetic of the coral and their symbionts.  Finally, we collect hundreds of high resolution images along the reef to generate a 3D mosaic model of the reef substrate so that we can understand the structural complexity of these reefs, and the species present, at this point in time. Pretty cool stuff!

Want to learn more? Check out the NOAA RAMP Papahānaumokuākea Marine National Monument research blog to see some great photos of the Health Team in action, and learn about the cool research our team has been conducting.
 
                             Studying Coral Health In Papahānaumokuākea

We've been traversing the Papāhanaumokuākea Marine National Monument for over a week now--traveling from the Main Hawaiian Islands to French Frigate Shoals, Maro Reef, and now at Pearl and Hermes Atoll--and we've seen and learned so much.  With such a large undertaking into a remote place like the Northwestern Hawaiian Islands, we are constantly reminded that our first priority is safety and health.  During our first days of transit from O'ahu to French Frigate Shoals we spent a lot of time familiarizing ourselves with safety protocols and emergency procedures--as well as learning to navigate with our sea legs. That last part can take time....

One of the members of the Science Party here on the NOAA ship Hi'ialakai, Andy Collins, wrote up a great piece about life on the research vessel and the experiences of our first few days at sea. 
You can read his blog post below...

                                           First Two Days at Sea and Entry Into Papahānaumokuākea

The first stop on our trip was at French Frigate Shoals.  It took approximately 3 days of transit to reach the atoll from Pearl Harbor, O'ahu.  We arrived at French Frigate Shoals in the evening, and conditions appeared to be in our favor, but on the horizon we could see a building lightning storm and a harbinger for the conditions to come.  During the night a squall moved in and we awoke to 6+ foot seas and less than desirable conditions.  For a first day out, it was a wild experience.  The crew on board the Hi'ialakai is well trained and accustomed to launching boats in all sorts of weather conditions, so we were in good hands, but the wind, swell, and strong current conditions made our research difficult. Personally, I've never been on a small boat being lifted by a crane off a ship into the middle of the Pacific, so this was quite the experience.  A good day to dust off and get accustomed to life in the Monument!

Enough about the boat--what's under the water! We were lucky that on our first day (yes, the difficult day) we were visited by a grey reef shark and a school of ulua aukea (giant trevally)  at our first site. A real treat for the first day off the boat!  It is always a treat to see megafauna, especially when they are not accustomed to humans and subjected to fishing pressure.  Now, as coral scientists we can appreciate fish and the ecological role they play in coral reef ecosystems, but we're really jazzed about those invertebrate reef corals--but fish are cool, too. 

Our group of researchers--the Coral Health Team--are looking at coral disease prevalence and indications of coral "health" as it pertains to coral bleaching, pathogen infection, tissue loss or necrosis, and growth anomalies.  In my work, I am interested in the bleaching and physiology of corals under thermal stress.  We observed some corals to be pale and some bleaching, but this may be within the normal range for corals in this habitat.  This is especially pertinent because French Frigate Shoals is the most southern of the atolls we were visit, and this year a heatwave from El Nino is expected to cause severe bleaching in the Main Hawaiian Islands, with decreased severity in the Northwestern Hawaiian Islands.   

Our group of researchers--the Coral Health Team--are looking at coral disease prevalence and indications of coral "health" as it pertains to coral bleaching, pathogen infection, tissue loss or necrosis, and growth anomalies.  In my work, I am interested in the bleaching and physiology of corals under thermal stress.  We observed some corals to be pale and some bleaching, but this may be within the normal range for corals in this habitat.  This is especially pertinent because French Frigate Shoals is the most southern of the atolls we were visit, and this year a heatwave from El Niño is expected to cause severe bleaching in the Main Hawaiian Islands, with decreased severity in the Northwestern Hawaiian Islands. 

At French Frigate Shoals, some coral taxa not found in the rest of the Hawaiian archipelago can dominate select reefs. These corals, such as  the tabular (i.e., table form) Acropora cytherea, are in a general sense sensitive to heat stress relative to more robust corals in the genus Porites--you might have seen these corals before (see image above), they look may look like colorful boulders, branching fingers, or encrusting skirts. Indeed, we observed the dominant coral on most of these reefs (Porites lichen) to be quite yellow (nearly florescent in color!), while others, such as the encrusting Montipora corals and branching Acropora were much more pale. 

So what differentiates a "pale coral" from a "bleached coral?" That's difficult to say, because corals do go through cycles of dark and less-dark (or pale) pigmentation throughout the year.  Remember, coral paling is a common process observed in summer months,  but the large scale bleaching events observed since the 1980s as a consequence of climate change and ocean warming, well these are not natural events.  Rather, this is the extreme end of a natural response, where instead of recovering from paling, corals are pushed over their thermal thresholds for prolonged periods leading to widespread mortality and death. The ability to discern a naturally pale versus an acutely stressed and bleached coral often comes form knowing the ecology of the corals at the taxonomic level as well as the history of these corals in the habitats they are found.
 

As a scientist working in the Monument, we are concerned about coral bleaching, and whether this area which is has experienced relatively few widespread bleaching events in the past will begin to have more bleaching in the future as the oceans continue to warm.  Indeed, the first ever recorded bleaching event in the Northwestern Hawaiian Islands occurred in 2002, and since then two subsequent bleaching events have occurred. Hopefully, this year will not mark a fourth mass bleaching event.  For now, we must continue our expedition and data collection in the hopes that by the time we have ended our surveys we will have a better understanding of the physiology, ecology, and "health" of reef corals in the Papāhanaumokuākea Marine National Monument.

Today, I am leaving for a research expedition into the remote, near-pristine ecosystem of the Northwestern Hawaiian Islands and the Papahānaumokuākea Marine National Monument.  This is a truly special place, where coral reef ecosystems have flourished largely in the absence of human activity.  Beyond the ecology, this area holds immense cultural significance to the Native Hawaiian people, and it is a blessing to be able to visit this sacred place as a scientist.

The Northwestern Hawaiian Islands Marine National Monument was established in 2006 (later given the Hawaiian name of Papahānaumokuākea) and the ecosystem has been declared a World Heritage Site by the United Nations.  The Hawaiian name reflects the religion of Native Hawaiians: the earth mother goddess Papahānaumoku (or Papa) and sky father Wākea.  Papa is the mother of islands, and the Hawaiian version of the Earth Mother deity found in other indigenous cultures.  

The Monument encompasses nearly 140,000 square miles of habitat providing homes for over 7,000 species and millions of nesting seabirds, the endangered Hawaiian Monk Seals, sea turtles, sharks and giant travel, as well as many maritime heritage sites (whaling ships, World War II battles).  Culturally, these islands have an important place in Hawaiian cosmology and religious practices, particularly on the islands of Nihoa and Mokumanamana (translation: island of immense spiritual power).  On the island of Mokumanamana, there exists the largest density of sacred spiritual sites in the entire Hawaiian archipelago (source: papahanaumokuakea.gov).

Photos: map of Papahānaumokuākea Marine National Monument and a reef assemblage at French Frigate Shoals. Images: http://www.papahanaumokuakea.gov, James Watt

The Cultural Perspective
Prior to out departure the entire field team had the privilege to hear the Native Hawaiian perspective on the cultural importance of the Papahānaumokuākea Marine National Monument. (Disclaimer: I am not Native Hawaiian, but have immense respect for their culture, and I hope I am able to communicate the importance of this place accurately and with the appropriate reverence). 
 
The Hawaiian archipelago can be viewed as a landscape divided into realms of life and death. In the east, there is life--the rising sun and the flowing lava, the creation of new earth and beginning of new days.  In the west, there is a returning to the ‘aina (land), or death--the setting sun, and the sinking of islands below the waves they once stood so audaciously above. The Hawaiian Island chain can be viewed cosmologically as two opposite forces:  the Ao (light) and the Pō (creation and death).  The Monument represents the Ke Ala Polohiwa a Kāne--the pathway to the afterlife--from the light in the east and Main Hawaiian Islands, and all things returning to their origin in the west. In this way, the Monument is a connection for Native Hawaiians to the spirit realm, and a place where the Iwi (ancestors) form a connection with the aiana (land).  Therefore, all items have a spiritual essence, and nothing is without meaning and purpose.  This is an important point for us scientists:  our data may be important to us, but what we are studying is sacred and represents a tremendous cultural resource and legacy.  

Geology of Coral Reefs
The cultural perspective on the birth of the Hawaiian islands and is necessary to appreciate the unique nature of the Islands to indigenous peoples.  Additionally, this also compliments well with what we know of the geology of Hawai‘i and coral reef islands.

The Hawaiian Islands are formed from a hotspot--a leaky, weak point in the oceanic crust where magma and molten rock from the mantle can escape.  This forms submarine volcanoes that eventually break the surface of the ocean to form islands.  These volcanoes can rise to magnificent heights (i.e., Mauna Kea on Hawai‘i Island is >13,000 feet above sea level).  As the Pacific Plate of the oceanic crust moves to the west, the island chain moves with it, but the hotspot is stationary, creating new islands to the east. Therefore, Hawai‘i Island is the youngest of the Main Hawaiian Islands and the remote atoll Kure is the oldest in the Main/Northwestern Island chain. As the plate moves to the west, erosion breaks the islands apart and the weight of the islands on the oceanic crust causes a slow but persistent rate of subsidence. During subsidence, the island's coral reefs expand outward forming barrier reefs, lagoons and atolls. Eventually, the island falls completely below the surface of the sea and becomes a seamount and the shallow coral reef slowly subsides with it. This is quite the life history! And you can thank Charles Darwin for coming up with this theory (yeah, that Charles Darwin), although this was quite a contentious topic for nearly a century.  In this way, the islands can be viewed through the lens of Hawaiian culture as birth in the east, and in the west all things must returning to the elements from which they came. 
(You can learn more about Darwin's theory of coral atoll formation and reef subsidence, here.)

Photo: The geologic hotspot and the Hawaiian Archipelago.  Credit: Encyclopedia Brittanica

An Unique Opportunity
Traveling into the Papahānaumokuākea Marine National Monument is a special opportunity.  This is a hallowed place, and we are fortunate to visit it.  This perspective was eloquently described as traveling to the home of all your ancestors, or grandparents' home: It is your responsibility--your kuleana--to never arrive at the threshold empty handed, to respect everything you see and touch, and to leave the place better than when you arrived. As scientists, we are bringing the gift of our knowledge and training to sustain and protect, to learn from and properly manage, this amazing place.  

NM Hall, KLE Berry, L Rintoul, MO Hoogenboom (2015) Microplastic ingestion by scleractinian corals. 
Marine Biology 162:725-732

THE PLASTIC PLANET
What are the implications of this study?  Well, first off, very little is understood about the impacts of microplastics on marine organisms outside of vertebrates--and even then the effects are mostly noted postmortem.  Corals are very important organisms in the ocean, and they build massive structures critical to the culture and livelihoods of millions of people.  But this extends beyond reefs: plastic pollution is affecting ecosystems across the world, and not just by muddying up your vacation photos on a sandy beach (#bummer).  Plastic pollution is killing migratory birds, marine mammals, and the  breakdown of plastics releases toxic chemicals known to cause cancer.   Further, these compounds may enter the food chain and bioaccumulate with the potential to affect whole trophic systems, including humans.  

In less than 100 years, humanity's uninhibited use of  plastic has  led to the  contamination of nearly every corner of the earth with plastic garbage--including remote beaches and coastlines far from humans (such as those found in the Papahanaumokuekea Marine National Monument).  But how much plastic is REALLY entering the ocean, you ask?  Well science has an answer!  In 1975, it was estimated (back of the envelope perhaps...) that 0.1% of plastic made it into the ocean. Not bad! Well, don't get excited... that number is grossly underestimated.  In actuality, 15 - 40% of plastic from dumps, landfills, and litter enters the ocean each year, totaling 4 - 12 million metric tons of plastic ANNUALLY!  What's worse is that we still don't know where all this debris is ending up--only a fraction actually makes it back to shore.  The remainder may sink as it becomes fractured or colonized by biofoulers, begin a new and perpetual  journey as part of the ocean's plankton, or sink to the ocean floor creating submarine garbage dumps. Clearly, something needs to change...   

The implications of our plastic planet for the health and function of ecosystems and organisms is uncertain, but it doesn't take a rocket scientist (or a marine scientist) to see the potential (and realized) threat of plastic debris on marine ecosystems.  It is urgent for humanity to reverse our dependency on petroleum (i.e., climate change) and petroleum products (i.e., plastics) because we don't have another 100 years to waste.

A friend shared this TED Talk with me today and I had to pass it on.  In this animated TED Talk, educator Neosha Kashef describes how life in the sea requires animals to tolerate extreme pressures and how human divers are affected by these pressures.  She also discusses how rapid changes in pressure due to uncontrolled ascents can affect fish and humans. In the case of fish, this could be a fish caught on a line that is reeled to the surface; in the case of the diver, this could be a result of improper buoyancy or due to an emergency.  

First, let's talk physics.  Bowles Law describes the relationship of gas volume and pressure, stating that the volume of a gas is inversely proportionate to pressure.  At the surface, atmospheric pressure is the least and therefore gases will have their greatest volume.  As you descend into the ocean, gas in our lungs and tissues becomes compressed with increasing pressure.  With each ~10 m (or 33 ft) change in depth there is a +1 increase of the atmospheric pressure experienced at sea level (= 1 atmosphere or "atm",  equivalent to ~14 pounds per square inch).  This means divers at 30 m experience ~ 4 atm of pressure!  This may sound minor, but your body feels this pressure, and this explains the sensation behind needing to "pop" (or equalize) your ears when you dive under water or (as the inverse) when ascending on an airplane.  Now, the extreme of this....get ready: fish and animals in the deep sea, such as the bathypelagic (open ocean 1,000-4,000 m) experience > 100 atm of pressure! This is enough to crush a  submarine like a soda can! This pressure is even greater in the abyssopelagic and hadopelagic (4,000-11,000 m). 

For animals with swim bladders--an organ that contains air to maintain neutral buoyancy in many (but not all) fish--a rapid change in pressure will cause the swim bladder to expand, literally pushing its eyes from its head and stomach out its mouth (ala, the video above). It is not a pretty site... Unlike the rockfish living at 100+ m, humans are acclimated to life at 1 atm pressure. When we venture into the ocean for a snorkel or SCUBA dive, we can feel the pressure increase in our head and the must equalize ("pop our ears") to eliminate this pressure we feel.  This may sound strange to the aquatic greenhorn, but it is easy :)  In the SCUBA diver, however, equalizing is not the entire story because the diver is breathing compressed gas. This air--mostly nitrogen (~80%) and oxygen (~20%) just like air on land--becomes more and more compressed as you descend deeper.  However, the partial pressure of these gases, or relative proportions of these gases in solution (i.e., the "partial pressure"), remains the same since the system is confined--i.e., your SCUBA tank. But, as you move deeper this air within the tank becomes more and more compressed, therefore more dissolved gases are moving into your blood, lungs and tissues than would happen at the surface.  This will also drain your SCUBA tank faster since you are breathing a more compressed air in each breath.  Just ask any diver how long they can breathe on their tank at 1 m vs. 30 m? Spoiler: you can dive at 1m for almost an hour, but may only spend a few minutes at depths > 30m before having to return to shallow depths.

Now back to our fish/diver barotrauma....If a diver, or a fish, makes a rapid ascent the gas in its tissues will expand. This expanded gas volume causes the air in the fish's swim bladder and our lungs to expand.  This can lead to serious trauma.  In divers, the increased gas volume may lead to lung over expansion and the formation of embolisms in vessels (usually in the arteries) where air bubbles obstruct the flow of blood.  In order to prevent barotrauma divers always ascend at a slow rate to allow for gas to leave the blood and to prevent gas expansion in the body.  Also during deep dives it is recommended to have decompression stops at ~ 5 m to allow dissolved gases to be released from your lungs (and blood) before returning to the surface where pressure is the least.  In the absence of these safety procedures a diver is at risk of developing decompression sickness, or the BENDS.  The bends describes the condition where compressed gases in blood and tissues expands once external pressure is reduced, in this case, upon heading to the surface. This is one of many reasons why normal SCUBA diving are not advised to go below 40 - 50 m. 

But how is it that humans can get the bends but other marine mammals don't?  Well the complicated answer is, yeah, other animals CAN get the bends by performing repeated dives, for example, to avoid predators or to hunt (Read about research on this topic from the journal Science).  However, the bends in marine mammals may be rare since marine mammals are efficient divers, possessing special adaptations affording them protections from barotrauma. Check out the video below to learn more about whales and the bends! 

Pressure as it relates to animals and SCUBA divers
I have been a SCUBA diver for nearly two decades. As a young man snorkeling, SCUBA, and surfing were the activities that motivated me to pursue marine biology as a career.  Today, as a grad student I am still pursuing this elusive "career"--and yes, sometimes I do feel like Captain Ahab.  SCUBA diving is safe and fun, and I firmly believe it offers a profound opportunity to foster a respect and appreciation for the ocean. So now that I'm all inspired from the TED talk, I'd like to discuss some cool points about diving, pressure, and how this affects marine organisms and humans, "in the vein (or artery)" of the aforementioned video.  

As a final note, the reason why divers, fish or marine mammals are not at risk of barotrauma or the bends when surface diving at shallow depths is because the air in our lungs (or swim bladder) is at 1 atm pressure at the surface.  This air is compressed at depth (>1 atm) and expanded back to its original mass at 1 atm pressure upon returning to the surface. There are other issues that can arise from extreme surface diving, so no matter what the activity, be educated in the proper safety procedures for your water activity.

Now enough of the factoids--go LEARN TO DIVE!  This is something anyone can do.  Today, you can take diving education classes and earn a SCUBA diving certification in most cities around the world.  Learn more about SCUBA and dive safety at Divers Alert Network (DAN) and become certified to dive by taking classes through PADI or NAUI diving groups.

Aloha!
-C

This last weekend I was blessed with the opportunity to visit the remote town and National Historic Park/Community of Kalaupapa on the island of Moloka'i. Moloka'i is just east of O'ahu in the Maui Nui Island Complex (Maui, Lanai, Moloka'i, Kahoolawe). In fact, from O'ahu you can see Moloka'i on the eastern horizon--but the two islands are dramatically different. For instance, Moloka'i has a population of < 8,000 compared to O'ahu's ~1 million. 

The isolated community of Kalaupapa has a long history in Hawai'i, one that is both sacred and deep in emotional and cultural connection to the people of Hawai'i.  The history of Kalaupapa extends back to the ancient Hawaiians that lived in this community during a period prior to European contact.  However, Kalaupapa's role in Hawaiian history is most known beginning in the 19th century during the rule of the Hawaiian Monarch. In the late 1860s Hansen's Disease (leprocy) was introduced to the Hawaiian Islands. King Kamehameha V proclaimed that people with the disease were to be forcibly sent to Kalaupapa where they would spend the rest of their days in isolation away from the their families and their community.  Approximately  8,000 people died in Kalaupapa, most of which were Hawaiians. Alongside the afflicted were many members of the Catholic clergy that spent time in Kalaupapa serving and engaging with Hansen's Disease patients; some gave their lives to this cause.   While there is a cure for Hansen's Disease today, patients sent to Kalaupapa still live in the settlement today.  The community in Kalaupapa is very special, and thanks to the larger community of Moloka'i and the National Parks Service, the sacred past of Kalaupapa has been preserved as a part of the history and heritage of Hawai'i.  

While in Moloka'i, I had some time to explore and take in the beauty of this remote coastline.  The National Park Service has done an amazing job at serving this community and preserving its history, but there is always more work to be done.   One thing I noticed, and was quite surprised to find, was the marine debris that had washed up on beaches in Moloka'i, and I would like to bring attention to this in the hopes of starting a discussion on how to remediate this problem. 

Preserving the coastal lands and beaches is a full time job, and outside of the community marine debris can be found scattered across this beautiful coastline.  This may be a surprise to you considering Moloka'i has such a small population.  Despite this small local population and the remoteness of Kalaupapa, debris carried to the ocean from rivers, adrift from other neighboring islands, and abandoned/derelict fishing gear have found their way to this isolated place.  

I imagine the debris problem in Kalaupapa is exacerbated by two causes: (1) limited access to this area and therefore limited observation and removal of debris, and (2) the financial and logistical constraints with removing such waste from this remove stretch of the north shore of Moloka'i (i.e., there are no roads into Moloka'i: there is a donkey trail and a landing strip for single propeller planes).

It is my hope that non-governmental organizations will be able to coordinate efforts with the National Parks Service and the Kalaupapa community to establish an effective way to remediate marine debris in Kalaupapa.  However, marine debris is a a global problem, amplified by our use of plastics and non-degradable materials.

Over 8 million tons of marine debris enter our oceans each year.  However, it is important to remember that not all forms of marine debris are large--some are UV-degraded small pieces (micro plastics).  Microplastics are particularly hard to remove due to its small size, and these debris can have devastating impacts on marine life that eat them, such as turtles, birds, and fish.  

So how can you aid in stopping marine debris? First, no matter where you live don't litter! This trash will eventually find its way to a water way and the ocean. Second, if you see trash, pick it up! This is effective at beaches and more terrestrial habitats. And finally, we should all work to reduce our collective reliance on plastics and non-degradable products such as plastic bags, plastic water bottles, and the like.  Wherever you live, look for groups that participate in waterway/beach cleanups. These are great opportunities to learn about your local aquatic habitats and to make an impact in reducing trash on land and in the sea. Contact the Sierra Club, Surfrider Foundation, or the Ocean Conservancy to get involved.

You can learn more about marine debris from the EPA (Trash Free Waters Program) and from NOAA (Marine Debris Program), and efforts to tackle marine debris in Hawai'i (Sustainable Coastlines Hawai'i).

Matter of fact: The Ocean Conservancy has a marine debris petition up NOW to addressed to Secretary of State John Kerry (an advocate for marine conservationism).  Visit their site for more information...