These bada$$ carbons are “isotopes”, sort of like fraternal twins (or triplets/quadruplets) where one is blazing their own path.  One of the twins is your regular Joe Shmoe who follows the rules and does everything by the book.  These are the ones shown in the periodic table.  The other twin in each set has the same number of protons as its boring twin, but it doesn’t follow the rules about how many neutrons they are supposed to have. They’re greedy little thieves. So, they are technically the same element, but they end up weighing different.  For instance, Carbon-13 has his regular six protons like its brother, but it has a whopping seven neutrons because it just haaaad to go and be extra cool. 

Almost every element has some number of isotopes/twins, except weird ones like Thulium and Holmium – but who even are those guys? Now, the wrong-number-of-neutrons outlaw twin can either be “stable” or “unstable”.  It’s like the difference between the cool guy in class and the guy who is so “cool” that he ends up expelled from school.  The stable ones are functional in society – in this case meaning they occur in nature without a problem.  The unstable ones are completely dysfunctional and over time try to turn back into their more stable twins by shedding neutrons.  It’s kind of like they just went too neutron-crazy, got a little wild, and now they’re all bloated and not having a good time. 

Knowing about these different carbons is important because stable isotopes can help reveal food webs.  Naturally occurring carbon consists of both the normal carbon and its bad boy twin.  We have a method that allows us to measure the ratio between the outlaw and the normal (we call this ratio the isotopic ratio). By measuring the carbon isotopic ratio of an animal, we can answer questions like what did this animal eat, what level consumer are they, and even what kind of eater are they (suspension feeder, predator, etc). This is especially important in my work because I want to understand how carbon from land makes it into the deep-sea food web. When I drop a big hunk of land carbon in the form of an alligator or a wood log (wood fall), I first measure the ratio of good boy to bad boy carbon in that particular hunk of food.  I also collect samples of the sediments around where I drop the food and measure the ratio of carbons in that sample too.  Then, after letting the food stay on the bottom of the ocean for a while, I can take animals directly off of it and take similar animals far away from the it.  When I measure the ratio of carbons in these animals, I can compare them to the ratio of the two food sources I measured and can understand which food source the animals are using.

The reason this all works is because of the saying “you are what you eat.”  Turns out that is actually true!  We know how much the good boy to bad boy carbon ratio should change from a food item to its consumer. This is especially helpful as we begin moving up the food web, because we can start to see who is eating whom – and this is something not yet well understood in the deep sea.

The post You are what you eat! Using bad boy carbons to understand food webs first appeared on Deep Sea News.

Off the Angolan African coast, these researchers document one whale shark and three ray carcasses at 1200 meters on the seafloor.  This is the first time any of these have been documented as deep-sea food falls and only recently have living whale sharks even been documented off Angola.

Despite one of the carcasses being covered in 54 eelpouts, a considerable amount of flesh still existed on the carcasses.

[in prior studies] When presented with elasmobranch and tuna bait on a baited camera trap, scavengers clearly preferred tuna and only consumed the elasmobranch once the tuna was gone…Repeated experiments in this region using [bony] fish as bait showed a 10-fold increase in scavenging rates compared to that when elasmobranch was used.

So why in a food desert like the deep sea would fresh meat not be consumed quickly?  Apparently, elasmobranch, i.e. shark and ray, flesh is bit unpalatable and tough to chew.  The tough, sand-paper-skin may prove a formidable barrier to scavenger jaws.  The high ammonia content of elasmobranch flesh may also be, to say the least, unappetizing.  The carcasses may also smell like death and deter other scavenging elasmobranchs.

Other uncharacterized chemicals that are found in rotting elasmobranch flesh (necromones) have been proven to strongly deter shark scavenging and invoke an alarm response, even among different species of elasmobranch. If this phenomenon extends to deep-sea scavenging elasmobranchs, it can be assumed that the Portugese dogfish, Centroscymnus coelolepis, would have been deterred from scavenging the elasmobranch carcasses. This will have severely hindered utilization of the carcasses by other species, since C. coelolepis is the dominant scavenger off the Angola margin.

Yet despite the smell of death and urine, a dead elasmobranch still provides an essential snack in the deep sea.  The researchers estimate that these elasmobranchs represent 4% of the total amount food that sinks to the seafloor off Angola in the form of marine snow.

Higgs, N., Gates, A., & Jones, D. (2014). Fish Food in the Deep Sea: Revisiting the Role of Large Food-Falls PLoS ONE, 9 (5) DOI: 10.1371/journal.pone.0096016

The post Dead Elasmobranchs on the Seafloor are Not as Appetizing as One Might Assume first appeared on Deep Sea News.

Keep this basic fact in mind as you consider that carbon production on land and in the oceans is radically shifting as our climate changes.  At least one study indicates that the global production of phytoplankton, the basis of the ocean’s food chain, is declining.  But the global pattern is more complex than that. The equatorial Pacific experienced overall declines of ∼50% over the last decade while polar regions experienced comparable increases. Clearly, we need a more complete understanding of the consequences of current and forthcoming climate change as it impacts the ocean’s food supply.

Research on both the species and habitats on land have provided us with some evidence of what might occur in the oceans.  As food increases, you expect there to be more life.  Animals should be more abundant and larger in size.  As food decreases, you should expect the opposite.  Yet, we do not know if energy is equitable distributed.  Do all species get equally larger and more abundant? Some species may be able to monopolize the food.  For example, prior research, mine included, suggests that certain sizes, especially the medium sizes, dominate the energy demand.   However whether this remains constant at both high and low food availabilities is unknown.

Food webs are also predicted to become more complex with increased energy. High food availability at the base of the food chain allows more energy to reach the top.  Thus more energy supports a greater diversity of top predators.  However, the differences in the body sizes of the prey and predators can turn this simple relationship on its head.

Increases in the number of different species might occur with increased food this is referred to as the species-energy rule.   More energy allows species to have a higher abundance.  This larger population is buffered against random detrimental events and less likely to go locally extinct.  Thereby more species would occur in the local community.  Alternatively, additional energy may elevate rare kinds of food, allowing rare species eating these rare foods to exist.  And given more energy, diversity may increase because those top predators are being supported.  These are just three of nearly a dozen different hypotheses relating food availability to biodiversity.  But lots of food may also lead to an alternative outcome where a superior competitor consumes all the food. Thus diversity may actually not change or even decline with more food.

I could spend the rest of this post writing about all the different theories and ways that a community of organisms could be impacted by changes in food.  However, it would remain just that, theory.  What we lack, especially for the oceans, is real data.  But studying the impacts of changing energy on a real community of species is difficult if not impossible.  One, we often lack knowledge of the total amount and source of energy in a habitat.  Two, it can be impossible trying to experimentally manipulate it.  How would you easily change the amount of food available in a forest?

This is where the wood fall project comes into the play. In 2006, Jim Barry (Monterey Bay Aquarium Research, MBARI) and I (when I was a MBARI postdoctoral fellow with Jim) chunked 36 logs into the deep to begin the examination of wood fall communities. The wood varied in size from 1.4 to 45.4 pounds.  The species that occur on the wood fall are completely reliant on the wood for food.  Indeed, wood falls are like little energetic islands.  They represent carbon availability 100-1000x greater than the surrounding deep-sea mud.  Wood falls are an oasis in a food desert.   With wood falls we know exactly where the energy originates and we can control the total amount of energy available to the community. In addition, we are able to track the flow of energy through the wood fall food web chemically using the unique carbon signature of the wood itself.

Wood falls are the best model system for understanding exactly how life is influenced by changes in energy. Wood falls are a window into how the oceans will respond to climate change.

We have just started analyzing the retrieved logs and our first paper is now in review!  The next step is to build the food web and look for the unique chemical thumbprint. These analyses cost anywhere from $10-$20 per sample and for an accurate assessment, we need dozens of individuals from the multitudes of species on the wood fall.

This important project opens a direct window into our ocean’s response to climate change. We need your help to make it happen. We’re a third of the way to our funding goal $4,000, but if we don’t make our goal by March 7^th, we don’t receive a penny of the funds. Please support our project with a donation today.  

https://experiment.com/projects/wood-is-it-what-s-for-dinner

The post Wood falls are an oasis in a food desert first appeared on Deep Sea News.

Meet The Hawaiian Petrel (or ʻUaʻu or Pterodroma sandwichensis) a bird species endemic to the Hawaiian Islands but with an appetite causing it to dine on squids, fish, and crustaceans from around the Pacific.  A single individual may take off on a 10,000 kilometer (>6,000 mile) trip just to feed.  Similar to those midnight runs to Krispy Kreme in the city hours away, when I was more youthful and my metabolism higher.  And much like my waste reveals that love of Krispy Kreme, Hawaiian Petrels so to show their diet.  The chemistry of the Hawaiian Petrel’s tissues, much like any animal’s, tells the story of this biologically and geographically diverse diet.

Both carbon and nitrogen can exist in a number of different isotopic forms with relatively lighter and heavier weights.  For example, most carbon is present as ¹²C, with approximately 1% being the heavier ¹³C.  The ratio of these isotopes is altered by both biological and geological processes.   For carbon, differences between ¹²C and ¹³C indicate different food sources based on different primary producers, i.e. plankton verses bacteria verses algae.  Nitrogen isotopes can tell us where a animal sets in the food chain, i.e. its trophic position.  Organism are much more likely to excrete, or urinate, the lighter  ¹⁴N than ¹⁵N.  Thus an animal’s tissues accumulate ¹⁵N which is passed along to predators.  Higher up the food chain the higher the ¹⁵N.

A  peek at the carbon and nitrogen ratios of Hawaiian Petrels in their collagen one can learn something about their feeding habits.  By examining both modern Hawaiian Petrels from recent collections and ancient Hawaiian Petrels from fossils, we might understand if dietary shifts have occurred through time?  Did the late 80’s/early 90’s fad of the Atkins diet impact Hawaiian Petrels?

Anne Wiley and colleagues discovered something astonishing when they examined 250 specimens spanning the last 4,000 years.  For 3,500 years everything was static.  The distint populations of Hawaiian Petrels on the different Hawaiian Island had a diverse set of diets from a diverse set of areas.  Birds on Hawaii and Lanai fed slightly higher on the trophic totem pole than those from Maui and Oahu. However, more recently, especially since 1950, something radical has taken place.  Despite the island they call home, all Hawaiian Petrels now feed on a very similar food source. In the last 100 years nitrogen ratios have declined by 1.8 parts per thousand.

Why the decline? Most likely industrial fishing.  Declines in trophic postion, decreasing nitrogen ratios have been seen in other birds as fishing pressure increases and fish prey decrease. As more predatory fish have declined, Hawaiian Petrels are forced to feed lower down the food web.

Anne E. Wiley, Peggy H. Ostrom, Andreanna J. Welch, Robert C. Fleischer, Hasand Gandhi, John R. Southon, Thomas W. Stafford, Jr., Jay F. Penniman, Darcy Hu, Fern P. Duvall, and Helen F. James Millennial-scale isotope records from a wide-ranging predator show evidence of recent human impact to oceanic food webs PNAS 2013 ; published ahead of print May 13, 2013, doi:10.1073/pnas.1300213110

The post An overfishing story told by bird collagen first appeared on Deep Sea News.

But the food not so delightful,


But since we’ve got no place to go,


Let It Marine Snow! Let It Marine Snow! Let It Marine Snow!

In the late 1960’s, two marine biologists, Howard Sanders and Robert Hessler, made a shocking find–the biodiversity of the deep-sea floor is astoundingly high. In an area the size of a coffee table over 300 species can coexist, a number that rivals tropical rainforests and coral reefs. Yet these findings also raised a paradox. High diversity is typically associated with physically complex habitats, like forests and reefs, plentiful with food that allow for a variety of niches. In the food poor, homogenous mud flats of the deep sea, how can so many species coexist? The answer is snow.

The lack of light in the deep oceans precludes photosynthesis. Thus, primary production of carbon, the base of a food web, is virtually absent. Deep-sea organisms are reliant upon a trickle of falling material from the productive shallow oceans overhead. This material is largely a low quality and low quantity mixture of decaying bodies and feces degraded further by bacteria on its decent into the deep. Roughly 2-5% of the total carbon on the ocean’s surface falls to the deep seafloor, the equivalent of roughly 2-3 tablespoons from a 5-pound bag of sugar. This sinking material, marine snow, falls as a dusting on the ocean bottom. But like a light snow in your yard does not form an even layer and Buffalo receives more snow than Miami, marine snow too is denser in some spots whether an area the size of coffee table or an entire ocean.

In this marine snow medley lays the answer for our deep-sea paradox.

In the 1970’s, Howard Sanders, Fred Grassle, and Paul Snelgrove proposed instead of the deep-sea floor being a homogenous wasteland, it was comprised of a variety of patches each with a unique set of organisms, i.e. the patch-mosaic hypothesis. The deep-sea floor is essentially a patchwork quilt of different small habitats. I began this year by publishing a study addressing how heterogeneity in marine snow of distances of just a few yards can lead to completely different communities of organisms. At the end of this year, just today in fact, I with coauthors show this same pattern over several thousands of kilometers.

In 2006, Jim Barry and I during my tenure at the Monterey Bay Aquarium Research Institute sampled a 3203-meter deep site off the Monterey Bay. We collected with the robotic arm of a remotely operated vehicle 44 sediment cores over approximately 400 yards. Each core we sieved and removed the small invertebrates living in the sediment, from worms to crustaceans to molluscs plus much more. Equally important, we measured the carbon content, of the sediment as an indicator of marine snowfall. Largely, we found that invertebrate communities in cores taken adjacent to each other were just as likely to be similar as dissimilar to one another. Indeed, cores adjacent to one another were just 3% more likely to share common species than cores taken 350 meters apart! Why would communities right next to one another be so different? Differences in marine snow accumulation. Invertebrate communities receiving comparable marine snowfall were more similar.

Today in the Proceedings of the Royal Society with collaborators Allen Hurlbert and James Stegen from the University of North Carolina, I unravel the paradox of the deep a little further. Given the difficulty of conducting deep-sea work, patterns of diversity of entire oceans are rare. In 2008, John Allen, working previously with Howard Sanders, published an amazing dataset of deep-sea bivalves taken form 270 sites across the Atlantic Ocean. We combined this dataset with data on bivalve sizes and genetic relatedness with multiple datasets on the environment, including annual marine snow accumulation. We found that the availability of both chemical, i.e. marine snow, and thermal, i.e. temperature, energy explained differences in compositions of bivalves communities across the Atlantic Ocean. Interestingly, and in contrast to current thinking (including my own!) that invertebrates with planktotrophic larvae should be able to disperse everywhere, we also detected the importance of dispersal ability in explaining community differences. In other words, some of what determines where a bivalve is located in the Atlantic is determined by its dispersal ability and the amount of energy it requires.

But we went one step further and developed a simulation. We constructed virtual bivalves allowing them to evolve traits, fill environmental niches, and disperse across a virtual Atlantic Ocean. This is a computationally complex and demanding operation and required a cluster of computers at UNC to run. In each simulation, we could control the dispersal ability and food requirements for the bivalves. For each simulation, we would then compare the patterns that emerged with those in our real Atlantic bivalves communities. This would allow us to determine the exact level of dispersal ability and food requirements of bivalves to produce changes in community compositions across the Atlantic. From our simulations, we found that 95% of bivalves could disperse 749 km from their natal site. We also found that 5% of bivalve juveniles would not be able to persist in habitats that deviated from their optimum habitat more than 2.1 grams of carbon per meter squared per year. That translates to about 1 teaspoon over a dining room table over the course of an entire year! Bivalves are extremely sensitive to the amount food available.

Overall, these studies illustrate that the deep-sea floor is like your Grandma’s quilt presenting a variety of patches of material. These patches, driven by differences in marine snow, whether occurring over inches or miles, provide unique habitats that allow a variety of different animals to coexist. And much like humans prefer different amounts of snow (give me warm weather or give me death!), deep-sea species are uniquely adapted to differences in marine snow.

Craig R. McClain, James C. Stegen, and Allen H. Hurlbert Dispersal, environmental niches and oceanic-scale turnover in deep-sea bivalves Proceedings of the Royal Society B: Biological Sciences published online before print December 21, 2011, doi:10.1098/rspb.2011.2166

UPDATE 1:
Also take a look at the great write ups by Wired and IO9. Love the titles! The Bounty of Species in a Single Scoop of Seafloor Mud and The Ocean Floor is Like a Rainforest Where Feces and Dead Animals Rain From the Sky

UPDATE 2: I was asked for a legend to the animals above.  Hopefully this helps. As for the species, I could give you the actual species names but perhaps that would not be helpful to readers.  Instead I will give you the general groupings that may be more informative.

So in this orientation above from left to right

Row 1 bivalve, polychaete, ophiuroid, polychaete, bivalve, cumacean, amphipod

Row 2 cumacean, anemone, aplacophoran, bivalve, cumacean, bivalve, aplacophoran

Row 3 polychaete, bivalve, cumacean, bivalve, big polychaete, amphipod, 2 oligochaetes

Row 4 scaphopod, bivalve, aplacophoran, long polychaete, cumacean, amphipod, bivalve

Row 5 bivalve, polychaete, aplacophoran, amphipod, bivalve, amphipod, polychaete

Row 6 ostracod, polychaete with tube, bivalve, anemone, polychaete, amphipod, polychaete, bivalve

Row 7 polychaete, gastropod, amphipod, caprellid shrimp, scaphopod, bivalve, polychaete, cumacean

Echinoderms

ophiuroid http://en.wikipedia.org/wiki/Brittle_star

 Molluscs

bivalve http://en.wikipedia.org/wiki/Bivalve

aplacophora http://en.wikipedia.org/wiki/Aplacophora

scaphopod http://en.wikipedia.org/wiki/Scaphopod

gastropod http://en.wikipedia.org/wiki/Gastropod

 Annelids

polychaete http://en.wikipedia.org/wiki/Polychaete

oligochaete http://en.wikipedia.org/wiki/Oligochaete

Crustaceans

cumacean http://en.wikipedia.org/wiki/Cumacean

amphipod http://en.wikipedia.org/wiki/Amphipod

ostracod http://en.wikipedia.org/wiki/Ostracod

caprellid http://en.wikipedia.org/wiki/Skeleton_shrimp

Cnidarian

anemone http://en.wikipedia.org/wiki/Sea_anemone

The post Let It Snow, Let It Snow, Let It Snow first appeared on Deep Sea News.

You are pretty, and I like you. Haeckel liked you too, so did Gaudi. Obviously, they appreciated the little things in life. While you still make appearances now and again in modern life, let’s face it: being microscopic and aquatic, recognition is an up-current battle, and you can’t swim.

Perhaps obscurity suits you? Trees, after all, are also beautiful, and we tend to cut them down. Perhaps your fame as a pool filterer is enough for you. Forgive me diatoms, but you can do better. You should do better.

Humans should know who to thank for producing 20% of their oxygen [Kroger and Poulsen, 2008]. Heck, without you and your heavy frustules to help bury carbon, there might never have been enough oxygen for placental mammals grow larger than shrews in the first place [Falkowski et al., 2005]! That’s right diatoms: no you, no us.

Being key to our past, you may also be key to our future. You see, we’re kind of sort of a little bit addicted to oil. Oil, as you know, comes from phytoplankton fat, and you are phytoplankton. Do your Bear Grylls-like survival skills in the face of toxicity (Brand et al., 1986), acidity (Warner, 1971), and unsurpassed ability for resource utilization (Boyd et al. 2007; Cullen 2006) make you the ultimate carbon-neutral source of oil? How will we know unless more people know enough about you to take an interest?

I like you diatoms, you are pretty. I have a lot to thank you for. You seem pretty happy with the fame you have, but I think it would help us out if you could try a little harder to get just a little bit more famous. Go on dancing with the stars, or Oprah. Something like that. Here, at least, is one person who would be very appreciative of your efforts.

Your admirer,
-Danny

For more reading see…

Kroger, N. and Poulsen, N. 2008. Diatoms—From Cell Wall Biogenesis to Nanotechnology. Annu. Rev. Genet. 2008. 42:83–107

Falkowski, P. F. et al., 2005. The Rise of Oxygen over the Past 205 Million Years and the Evolution of Large Placental Mammals. Science 309, 2202

Brand, L. E., W. G. Sunda, and R. R. L. Guillard. 1986. Reduction of Marine-Phytoplankton Reproduction Rates by Copper and Cadmium. Journal of Experimental Marine Biology and Ecology 96: 225-250.

Boyd, P. W. and others 2007. Mesoscale iron enrichment experiments 1993-2005: Synthesis and future directions. Science 315: 612-617.

Cullen, J. T. 2006. On the nonlinear relationship between dissolved cadmium and phosphate in the modern global ocean: Could chronic iron limitation of phytoplankton growth cause the kink? Limnology and Oceanography 51: 1369-1380.

Warner, R. W. 1971. Distribution of Biota in a Stream Polluted by Acid Mine-Drainage. The Ohio Journal of Science 71(4): 202.

The post Scientist In Residence: Danny Richter on the To Humble Diatom first appeared on Deep Sea News.

Spreading plate boundaries…meh.  What I do like is new research basically stating, and I am paraphrasing here, that spreading plate boundaries can suck it.

Let me explain. Over 30 miles away from these fancy spreading plate boundaries, the furthest distance ever documented, magma is rising below the seafloor surface.   However, this magma is stopped when it reaches the barrier of thick mud that covers the seafloor.  The magma forms a large horizontal sheet, a sill.  Think of that irritating girl your best friend dated long ago.  She wasn’t enough to break your friendship but she sure did intrude.  You and your friend are the mud and she is the magma. Welcome to the concept of intrusive volcanism.  “O’ pardon me.”

Unlike your best friend’s former girl, the sills are hot.  But like your former best friends girl, they produce 10 times as much carbon dioxide and methane gas.  This occurs because the sill heats the overlying mud and thermally alters it.  These rising gases can spawn biologically activity like hydrothermal vents, but all very far from the spreading center where vents were previously thought to be concentrated..

More importantly, typically deep-sea mud is thought to store carbon, i.e. sequester carbon.  But this research suggest  these magma intrusion could potentially release significant amounts of carbon from the sediment.

*Go Butler

Lizarralde, D., Soule, S., Seewald, J., & Proskurowski, G. (2010). Carbon release by off-axis magmatism in a young sedimented spreading centre Nature Geoscience DOI: 10.1038/NGEO1006

The post I Like Sills But Not A Fan Of The Popular Or My Friend’s Ex first appeared on Deep Sea News.

A new paper by Boyce, Lewis, and Worm from Dalhousie University, provides clear evidence of decreasing phytoplankton biomass over the last century. The researchers used a blended dataset of ~450,000 measurements of chlorophyll consisting of field measurements of chlorophyll concentration in the water and water transparency taken between 1899 and 2008. Statistical analyses were conducted to ensure that the two types of measurements were comparable. The researchers found that for eight out of ten ocean regions, phytoplankton biomass decreased. Greater decreases were observed with increasing distance from land. On the continental shelf phytoplankton biomass actually increased since 1990 likely due to the intensifying of nutrient input, i.e. eutrophication, from land runoff. The researchers find the overall decreases in phytoplankton biomass to be correlated with sea-surface temperatures in the eight regions.

Why this paper is cool? A recent suite of studies based on either chlorophyll concentrations measured with satellites or field chlorophyll measurements indicate that major changes have and are occurring to ocean phytoplankton. These studies have produced mixed findings on the exact nature of this change. In part this reflects the lack of long-term time series, satellite imagery for the oceans only goes back to the 1970’s, or the often regional focus of field studies. This paper represents one of the few that is both global in scope and provides such a long-term historical view. The findings of this paper are not only consistent with these previous studies but help to reconcile observed differences in phytoplankton trends among the varying oceans.

Boyce, D., Lewis, M., & Worm, B. (2010). Global phytoplankton decline over the past century Nature, 466 (7306), 591-596 DOI: 10.1038/nature09268

In Proceedings of the National Academy of Science, Sharp et al use Thorium-230 dating of corals used in temple construction on a Polynesian island to examine the development of architectural elements. These formal temples, marae, consisted for a formal court, upright slabs representing deities, and elevated altar or ahu. Depending on the importance and wealth of the chief, marae size and complexity could vary.   As shrines and temples typically reflect a rise in society complexity and formation of early states, dating the emergence and elaboration of temples provides insights into the development of culture. The authors found on the island of Mo’orea that temple architecture developed quickly over a mere 140 years and predated European arrival. Key architectural elements like coral veneers were superceded by cut and dressed coral blocks and followed by the innovation of multitier stepped ahu.

Why this paper is cool? Ceremonies at the marae required human sacrifice to the war god ‘Oro. Corals, chemistry, radioactivity, ritual killings, war gods, development of society complexity and ornamentation…this study has everything. Coincidentally these are also the same things that characterize one of Kevin Z.’s parties

Sharp, W., Kahn, J., Polito, C., & Kirch, P. (2010). Rapid evolution of ritual architecture in central Polynesia indicated by precise 230Th/U coral dating Proceedings of the National Academy of Sciences, 107 (30), 13234-13239 DOI: 10.1073/pnas.1005063107

A majority of deep-sea systems are food limited and reliant on carbon produced at the ocean’s surface sinking to the seafloor. Much attention is given to how the amount of food available dictates the number of species. Much less attention is given to how the amount of food can determine what species are in a locality. A comprehensive study on the small organisms living in muddy ooze of the deep Gulf of Mexico addresses this question. Sampling from depth of 200 to 3700 meters throughout the Gulf, Chih-Lin Wei and colleagues quantified nearly 1,000 species. The distribution of species in the Gulf is significantly correlated with export particulate organic carbon (POC) flux from the ocean’s surface. In fact, POC and depth explained over 70% of the variation in composition of ecological communities. Communities east and west of the Mississippi River, suggesting the potential importance of the submarine canyon, changes in currents, or sediment and organic input are also important in determining Gulf of Mexico biodiversity.

Why this study is cool? This is the study I wish I would have done and the paper I wish I would have written.  The study represents one of the most comprehensive deep-sea surveys to date. At least 5 cores were taken at each of the 51 stations throughout the Gulf. But the paper goes beyond just describing pattern and moves toward the processes that determine deep-sea biodiversity.

Wei, C., Rowe, G., Hubbard, G., Scheltema, A., Wilson, G., Petrescu, I., Foster, J., Wicksten, M., Chen, M., Davenport, R., Soliman, Y., & Wang, Y. (2010). Bathymetric zonation of deep-sea macrofauna in relation to export of surface phytoplankton production Marine Ecology Progress Series, 399, 1-14 DOI: 10.3354/meps08388

The post The Tide Pool: Loss of Phytoplankton, War Gods and Corals, and Gulf of Mexico Biodiversity first appeared on Deep Sea News.

To trace the pathway of autotrophically-derived carbon CO₂, the carbon substrate of photosynthesis, was labeled with a radioactive isotope (¹⁴C in sodium carbonate). The fate of heterotrophic carbon was tracked by feeding the anemones brine shrimp (Artemia sp.) raised on algae incubated with the same radio-labeled CO₂ source.  In what is referred to as a Pulse-Chase experiment, the anemone was pulsed with radio-label in the seawater for 12 hours in the light and 12 hours in the dark. During the “chase” period the anemone is removed from the radio-labeled environment. At this time, the products of photosynthesis make their way from the Zooxanthellae into the tissues of the anemone.

Finally, you make an Anemone Slushie!  The recipe is as follows:

Ingredients

• 1 dash acid to evolve off the unassimilated inorganic carbon
• 1 experimental anemone
• 1 centrifuge
• 1 coffee bean grinder or blender

Place experimental anemone in coffee bean grinder or blender for 30-60 seconds at medium speed. Pour mixture into a vessel, place in centrifuge (don’t forget to balance!) and spin for 5 minutes, ensuring all algal cells are at the bottom of vessel. Pour top portion containing anemone tissue slurry into a new vessel and discard algal portion. Add a dash of acid to remove unassimilated inorganic carbon. Voila! You have yourself a delicious Anemone Slushie, a tasty family treat.

What Bachar and colleagues did was to trace the fate of carbon in the lipid portion of the Anemone Slushie in addition to the whole tissue (i.e. animal) portion of the Slushie. What they found was interesting:

“The radioactivity levels of both the lipids and the total tissue of the sea anemones that were fed labeled autotrophic or heterotrophic carbon show that for the autotrophic anemones, the fastest change occurred in the lipid tissue, while for the heterotrophic anemones, it took place in the entire tissue.” (see Fig. 2 from the paper below)

As the authors claim in their abstract, this study is the first that differentiates between the fate of autotrophic- and heterotrophic-derived carbon in a mixotrophic organism. It suggests that autotrophic-derived carbon is converted to lipids, potentially as a quick and dirty energy source for metabolism and respiration, while heterotrophic-derived carbon is dispersed throughout the body, possibly for structural purposes (i.e. cell membranes, growth).

Autotrophic carbon, derived from carbon dioxide, is a short chain molecule so it makes sense that this would be used as an immediate energetic source since it can be easily converted into molecules like pyruvate and acetate which can ease right in to the metabolic cycles. On other hand, heterotrophic carbon is typically longer chain, like fatty acids and sugars, which need to be broken down into smaller parts to be used for metabolism. These might be more appropriate carbon sources for structural components which are typically longer-chain carbon compounds like collagen and phospholipids.

Though scientists have known about algal-cnidarian symbioses for a long time, it has taken decades of work to just figure out the what and how. Bachar and colleagues’ paper gives us the where and some further insight in some more of the how. It is still unclear “why” though and the “how” in an evolutionary sense. Symbiosis is a field still very ripe for exploration. All the studies ever done on host-symbiont phylogenies, carbon translocation, physiological ecology are just the tip of the iceberg. Autotrophic symbioses are everywhere and occur in many animal phyla from cnidarians to nematodes to molluscs.

BACHAR, A., ACHITUV, Y., PASTERNAK, Z., & DUBINSKY, Z. (2007). Autotrophy versus heterotrophy: The origin of carbon determines its fate in a symbiotic sea anemone Journal of Experimental Marine Biology and Ecology, 349 (2), 295-298 DOI: 10.1016/j.jembe.2007.05.030

This post was modified from an August, 2007, post at The Other 95%.

The post Determining the Fate of Carbon in a Mixotrophic Anemone first appeared on Deep Sea News.

“Whales, like any animal or plant on the planet, are made out of a lot of carbon,” he said.

“And when you kill and remove a whale from the ocean, that’s removing carbon from this storage system and possibly sending it into the atmosphere.”

He pointed out that, particularly in the early days of whaling, the animals were a source of lamp oil, which was burned, releasing the carbon directly into the air.

“And this marine system is unique because when whales die [naturally], their bodies sink, so they take that carbon down to the bottom of the ocean.

“If they die where it’s deep enough, it will be [stored] out of the atmosphere perhaps for hundreds of years.”

Pershing’s solution is to offer a trading scheme similar to carbon credit trading. Whaling nations can receive good carbon karma for not whaling or whaling less. I haven’t seen the talk nor read a paper on this so do not feel qualified to opine on this matter. The troubling aspect to me is the general idea sinking things to the deep-sea is a great way to solve problems. Out of sight, out of mind right?

What happens to a whale after it sinks to the seafloor? Let’s review!

Figure 1: Whale Death Cycle. Some images from If Its Hip, Its Here, Craig Smith (U. Hawaii) and MBARI.

But, let a wee bit closer look at those bones, looks like some fuzzy stuff on them.

Figure 2: Osedax, only discovered in 2004, now has more than a dozen species described. Figure from Vrijenhoek et al. 2009 in BMC Biology (open access).

BOO YA!! Bone-eating zombie worms from hell in your eyez!! All your precious carbon, locked away in the forbidden depths of the abyss, still gets recycled. I don’t know how long it takes, but eventually, some point in time, some of that carbon will get released back into shallower waters through gametes broadcast upwards or upwelling of currents. Some will get buried, but in millions of years as the plates shift and subducted, what was once laying on the seafloor will be crushed and melted come out of a volcano. Should we be worried? Probably not, but I bet his calculations don’t take into account release of carbon through decomposition on the seafloor. Not mention that the release of the lipids from whale bone creates a sort of mini-seep around the skeleton which generates methane, another greenhouse gas.

The real problem with whaling is the destruction of this important habitat – the Whale Fall habitat. Every whale removed from the ocean is an ecosystem LOST to a unique and diverse community in the deep sea. A stepping stone connecting disparate populations LOST. A novel metabolic pathway or potential new drug discovery LOST. An important undiscovered species that may hold a key insight into the evolution of its group LOST. In 2009, Japan harvested 680 whales – 680 rare, long-lived, nutrient-recycling ecosystems LOST. Won’t someone think of the poor, little bone-eating worms and all the other unique animals that rely on whale carcasses for their home?

(Hat tip to a crazy drunken Irishmen for the inspiration.)

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