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Ecology / Conservation posts

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  • May 19, 2017
  • 10:21 PM
  • 61 views

The warmer the dangerouser, at least if you are a caterpillar

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Scientist all over the world agree that species diversity is higher at the tropics than at polar regions, i.e., the closer you get to the equator, more species you will find. But apart from making food … Continue reading →... Read more »

Roslin, T., Hardwick, B., Novotny, V., Petry, W., Andrew, N., Asmus, A., Barrio, I., Basset, Y., Boesing, A., Bonebrake, T.... (2017) Higher predation risk for insect prey at low latitudes and elevations. Science, 356(6339), 742-744. DOI: 10.1126/science.aaj1631  

  • May 19, 2017
  • 07:00 AM
  • 64 views

Friday Fellow: Common Stinkhorn

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Today things are getting sort of pornographic again. Some time ago I introduced a plant whose flowers resemble a woman’s vulva, the asian pigeonwing, and now is time to look at something of the other sex. … Continue reading →... Read more »

  • May 16, 2017
  • 10:15 AM
  • 94 views

Fatal Attraction: Praying Mantises (A Guest Post)

by Miss Behavior in The Scorpion and the Frog

By Britta Bibbo We all know the character: an incredibly beautiful woman that seduces the rough-and-tumble action hero, only for him to later find himself chained up over a lava pit with sharks in it! …Or something like that. A “femme fatal” is the idea of a beautiful woman who leads men to their demise. None are more perfect for this role than the female praying mantis. Praying mantis females practice the art of deception through sexual cannibalism. It’s exactly how it sounds: the male is attracted to the female and tries to make some babies, but instead ends up being devoured. Sexual cannibalism hardly seems like a good strategy for keeping the mantis population up, but some argue it’s merely females taking advantage of every scrap of food they can find… even if it’s a loving male. False garden mantis (Pseudomantis albofimbriata). Image by Donald Hobern from Wikimedia Commons.When male mantises encounter a female in the wild they only have one thing on the brain, while a female may be more interested in self-preservation. If she hasn’t encountered food for a few days she will be VERY hungry and not all that interested in mating; in many species of mantises it is known that female mantises will eat males, even while having sex! So how do female mantises attract males? For most insects, females are able to attract males with pheromones, chemicals released from an individual that affect other individuals of the same species. For instance, females can emit pheromones that will be telling of their age, reproductive status, and body condition. Males are able to detect pheromones from great distances and these pheromones play a role in allowing a male to determine how attractive a female could be. Before any sexy time can begin, females have to show that they are open to male advances. Showing a male you’ve never met before that you’re interested can be a difficult task- so females typically emit pheromones that are known as honest signals. These signals accurately convey female interest in mating, as well as her reproductive status, age, and body condition. Because the majority of females are being honest, males don’t have to think twice about their mate’s intentions. This is where female deception comes into play. If a female takes advantage of the lack of male wariness, she could end up with an easy meal. This deception by the females is what scientists know as the Femme Fatale hypothesis. This hypothesis explains that female mantises are naturally selected to deceive male mantises, and exploit them as food. This idea hasn’t had much backing evidence until Dr. Kate Barry of Macquarie University in Sydney, Australia sought to test this hypothesis with the false garden mantis (Pseudomantis albofimbriata). After considering the test subjects and how the mantises communicate, Kate expected one of three possible outcomes: 1. There will be no pattern between female hunger and male attraction (if female false garden mantises are not femme fatales and false garden mantis pheromones do not communicate feeding-related information). 2. The well-fed females will attract the most males, while hungry females will attract the fewest males (if female false garden mantises are not femme fatales and females are always honest about their quality and willingness to mate). 3. The hungriest females will attract the most males, while well-fed females will still attract some males (if female false garden mantises are femme fatales and females are dishonest about their quality and willingness to mate when they are hungry). To test her expectations, Kate gathered juvenile mantises that were close to their adult forms to have many male and female mantises that have no previous mating experience. Once the mantises were adults, females were given different feeding regimens to have a range of hunger. Categories included Good (well-fed), Medium (slightly less fed), Poor (hungry), and Very Poor (very, very hungry). Adult mantises were housed in a circular cage that separated each female individually around the edge, while the males were kept in the center. Diagram of cage experiment was conducted in. Image by Britta Bibbo.To allow the males to smell the female pheromones, researchers separated males by special walls that the males could not see through, but could still detect the pheromones given off by a female. The number of males on a female’s side of the cage was used to measure how attractive her pheromones were to the males. The results of this study concluded that pheromones produced by the females that were very hungry were the most attractive to males. Through deception, the hungriest females are seen as sexier than well-fed, healthy females that are willing to mate! This result is surprising; normally females that are well-fed are seen as “sexier” because they have more nutrients available to them, making them more fertile. Hungry females have fewer nutrients available to them, making them less fertile, and therefore not as “sexy”. These hungry female mantises are advertising themselves as well-fed, fertile, and ready to rock when really, they’re not. Simply put, these results show that males are being catfished, and then consumed. Whether hungry females are actively trying to deceive males or if it’s just coincidental still needs to be looked into, but for now, be thankful for a partner who will see you as more than just a piece of meat! Literature Cited:Barry, K. (2014). Sexual deception in a cannibalistic mating system? Testing the Femme Fatale hypothesis Proceedings of the Royal Society B: Biological Sciences, 282 (1800), 20141428-20141428 DOI: 10.1098/rspb.2014.1428 ... Read more »

  • May 12, 2017
  • 07:00 AM
  • 134 views

Friday Fellow: Spreading Earthmoss

by Piter Boll in Earthling Nature

by Piter Kehoma Boll If you still think mosses are uninteresting lifeforms, perhaps you will change your mind after knowing the spreading earthmoss, Physcomitrella patens. Found in temperate regions of the world, except for South America, but more commonly recorded in … Continue reading →... Read more »

Cove, D. (2005) The Moss Physcomitrella patens. Annual Review of Genetics, 39(1), 339-358. DOI: 10.1146/annurev.genet.39.073003.110214  

  • May 11, 2017
  • 09:26 AM
  • 148 views

Land snails on islands: fascinating diversity, worrying vulnerability

by Piter Boll in Earthling Nature

by Piter Kehoma Boll The class Gastropoda, which includes snails and slugs, is only beaten by the insects in number of species worldwide, having currently about 80 thousand described species. Among those, about 24 thousand live on land, where they are … Continue reading →... Read more »

  • April 28, 2017
  • 07:00 AM
  • 175 views

Friday Fellow: Hooker’s Lips

by Piter Boll in Earthling Nature

by Piter Kehoma Boll We are always fascinated by plants that have some peculiar shape that resemble something else. And certainly one of them is the species I’m introducing today, Psychotria elata, also known as hooker’s lips or hot lips. Found … Continue reading →... Read more »

  • April 27, 2017
  • 08:49 AM
  • 223 views

Code Orange for the Bengal Tiger!

by Jente Ottenburghs in Evolutionary Stories

Genetic study highlights challenging conservation of the Bengal Tiger in India.... Read more »

  • April 21, 2017
  • 07:00 AM
  • 126 views

Friday Fellow: Crystalline crestfoot

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Even in the smallest pools or ponds of freshwater lost in a field, the diversity of lifeforms is amazing. Sadly, these environments are one of the most damaged of all ecosystems on earth and we probably … Continue reading →... Read more »

  • April 14, 2017
  • 07:00 AM
  • 73 views

Friday Fellow: Crawling Spider Alga

by Piter Boll in Earthling Nature

by Piter Kehoma Boll The world of unicelular creatures includes fascinating species, some of which were already presented here. And today one more is coming, the marine phytoplanctonic amoeboid protist Chlorarachnion reptans, which again is a species without a common name, … Continue reading →... Read more »

  • April 11, 2017
  • 10:22 AM
  • 351 views

Risking Limb for Life? (A Guest Post)

by Miss Behavior in The Scorpion and the Frog

By Matthew Whitley Imagine you are walking alone in parking lot, when suddenly somebody grabs you by the arm and flashes a knife, demanding your money. Do you A) scream for help, B) try to wrestle the knife away, or C) remove your arm from your shoulder and make a break for it? Disarming your assailant may seem preferable to dis-arming yourself, but for a lizard option C is a likely response. A lizard tail left behind. Image by Metatron at Wikimedia Commons.You likely have heard before that many lizards can break off their tail when trying to make an escape. This ability is called caudal autotomy; autotomy meaning the ability to shed a limb, and caudal simply being a fancy word for tail. Of course, losing a limb is no simple procedure, and lizards possess many specialized features to make caudal autotomy possible. There are two main kinds of caudal autotomy in lizards: intervertebral and intravertebral. Intervertebral refers to when the tail breaks between vertebrae, and is considered the simpler and more primitive form. Intravertebral, on the other hand, involves some more complex features. The word intravertebral refers to fracture planes found in the middle of each vertebra in the middle of the lizard’s tail. At these fracture planes, the bone can easily snap in half. This snapping of bone is performed by the lizard itself—when its tail is caught, muscles surrounding the bone just above where its tail is held squeeze tight until the bone breaks. After the bone breaks, the rest of the tail follows: the skin stretches and breaks, muscles detach, any remaining tissue divides, and—POP—the tail falls off! After snapping your arm off to run from an attacker, you would probably just bleed out in your retreat, but lizards have that covered. In their tails, lizards have sphincters (rings of muscle) along their arteries—vessels that normally carry blood to the tail. When the tail is detached, these sphincters tighten to prevent blood from gushing out. Additionally, their veins, which normally bring blood back from the tail, have valves that prevent blood from flowing backwards, similar to the valves in your heart. And while the lizard makes its escape, the dislocated tail jerks and twitches, which distracts the lizard’s assailant. The tail owes its spastic actions to fast, glycolytic muscles, a variety of muscle that can act quickly and with a lot of force, but wears out quickly. After our reptilian friend has made its daring escape, it has a new problem—it has no tail. A lizard without its tail is at a disadvantage, just as you would be without your arm. Lizards rely on their tails for several functions, including movement, nutrient storage, and social and sexual behaviors. Fortunately, lizards that exercise caudal autotomy can actually re-grow their tails, a process which itself is highly complex. In lieu of a lengthy explanation of another amazing phenomenon, I’ll share this tidbit: to regain lost nutrients and help recover, some lizards have been known to go back and eat their lost tail! So when you tear off your arm to escape a mugger, don’t forget to return to the scene of the crime to self-cannibalize…or maybe just buy some pepper spray beforehand. Here you can see that the lizard is caught by the tail, pops it off and runs away, and the tail is left twitching.Works CitedBateman, P., & Fleming, P. (2009). To cut a long tail short: a review of lizard caudal autotomy studies carried out over the last 20 years Journal of Zoology, 277 (1), 1-14 DOI: 10.1111/j.1469-7998.2008.00484.xClause, A., & Capaldi, E. (2006). Caudal autotomy and regeneration in lizards Journal of Experimental Zoology Part A: Comparative Experimental Biology, 305A (12), 965-973 DOI: 10.1002/jez.a.346Gilbert, E., Payne, S., & Vickaryous, M. (2013). The Anatomy and Histology of Caudal Autotomy and Regeneration in Lizards Physiological and Biochemical Zoology, 86 (6), 631-644 DOI: 10.1086/673889 ... Read more »

Clause, A., & Capaldi, E. (2006) Caudal autotomy and regeneration in lizards. Journal of Experimental Zoology Part A: Comparative Experimental Biology, 305A(12), 965-973. DOI: 10.1002/jez.a.346  

Gilbert, E., Payne, S., & Vickaryous, M. (2013) The Anatomy and Histology of Caudal Autotomy and Regeneration in Lizards. Physiological and Biochemical Zoology, 86(6), 631-644. DOI: 10.1086/673889  

  • April 7, 2017
  • 07:00 AM
  • 78 views

Friday Fellow: Amphibian chytrid fungus

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Today I’m bringing you a species that is probably one of the most terrible ones to exist today, the amphibian chytrid fungus, Batrachochytrium dendrobatidis, also known simply as Bd. The amphibian chytrid fungus, as its name says, is … Continue reading →... Read more »

  • April 4, 2017
  • 06:00 PM
  • 191 views

New rice fights off drought

by adam phillips in It Ain't Magic

Researchers have created drought resistant transgenic rice using a gene from a small Eurasian flowering plant.... Read more »

  • March 31, 2017
  • 10:16 AM
  • 237 views

The Snail That Only Lives in a Hole inside Another Hole under a Sea Urchin

by Elizabeth Preston in Inkfish



If you think house hunting is hard, consider the plight of this snail. It lives only in tide pools in southern Japan. Within those tide pools, it only lives in holes carved out of rock—specifically, holes dug by sea urchins. But it can only move into one of those holes after the hole-digging urchin has moved out. When a second, differently shaped sea urchin moves into the hole, it leaves a gap between its spiny body and the wall of the burrow. It's this nook that the snail snuggles into.

... Read more »

  • March 28, 2017
  • 04:48 PM
  • 289 views

Bottlenose Dolphins: The Ultimate Sea Bully? (A Guest Post)

by Miss Behavior in The Scorpion and the Frog

By Kayla FullerImagine this situation: you’ve brought your favorite lunch to work. Everyone is jealous of your food, continuously eyeing it up. A few coworkers, who have brought in disappointing lunches in comparison, approach and demand that you hand it over. After you refuse, they beat you until your body lies lifeless and they take your lunch anyway. Woah, woah, woah… that took a dramatic turn! Photo of a harbour porpoise, taken by AVampireTear (Wikimedia Commons)But for harbour porpoises in the northeastern Atlantic, this fight for food has become a reality, and bottlenose dolphins are the suspected culprit. In 1996, Harry M. Ross (SAC Veterinary Services, U.K.) and Ben Wilson (University of Aberdeen, U.K.) documented fractured rib cages, damaged internal organs and joint dislocations of deceased harbour porpoises in the northeastern Atlantic. Why would bottlenose dolphins be causing such damage? Who could ever associate such a cute and cuddly creature with a horrific crime like this? Photo of a bottlenose dolphin, taken by NASA (Wikimedia Commons)Researchers Jérôme Spitz, Yann Rousseau, and Vincent Ridoux with the Center for Research on Marine Mammals: Institute for Coastal and Environmental Research at the University of La Rochelle in France become the judge and jury in this trial. Jérôme, Yann, and Vincent obtained 29 harbour porpoises and 25 bottlenose dolphins that had been beached and died in the Bay of Biscay (between Spain, France, and England). At the time of the study, more harbour porpoises were being found dead in the bay than in previous years. They hypothesized that bottlenose dolphins and harbour porpoises may have had similar enough diets to cause competition and violence between the two species. Photo of a harbour porpoise that received injuries thought to be from abottlenose dolphin before death (circled), from Ross and Wilson (1996)The researchers’ goal was to analyze stomach contents to directly see what each mammal was eating at the time of their death. To do this, Jérôme, Yann, and Vincent removed the stomachs from the harbour porpoise bodies and weighed them with all contents included. After weighing stomach casings separately, they calculated total weight inside of the animals’ stomachs. Then, they washed stomach contents through a filter to separate out larger matter. Now, if you have a weak stomach, this probably wouldn’t be the job for you. Jérôme, Yann, and Vincent separated food items within the stomachs into identifiable categories. It could sometimes be difficult to recognize whole animals in a stomach due to breakdown, so methods like pairing dismantled eyes or counting fish bones was necessary to identify them! This same process was repeated for bottlenose dolphin carcasses. From there, the scientists compared specimens for prey presence, abundance, mass, and size to see if there was overlap between diets of the harbour porpoises and bottlenose dolphins.So what did they find? More food mass, a greater number of species, and a more diverse size range of prey was found in the stomachs of bottlenose dolphins in comparison to harbour porpoises. Although bottlenose dolphins have a habitat that includes more deep-ocean areas while harbor porpoises inhabit coastal surroundings, certain prey species were eaten by both. Since bottlenose dolphins are bigger and hunt in larger groups, they would logically be more dominant in a face-off over a common prey item. Why are they fighting more over the same foods? This shift could be a result of humans harvesting species from the ocean that are diet items for bottlenose dolphins. It could also be a result of warming ocean temperatures that could be changing the dwelling places of available food for bottlenose dolphins. This would explain why more habour porpoises are being attacked by these marine tyrants moving into shallower waters. Poor porpoises, all they want to do is eat their lunch in peace. Who knows, maybe in the next few million years, we’ll see highly evolved harbour porpoises covered in spikes to ward off the dolphins. That’ll teach those bullies! References:Ross, H., & Wilson, B. (1996). Violent Interactions between Bottlenose Dolphins and Harbour Porpoises Proceedings of the Royal Society B: Biological Sciences, 263 (1368), 283-286 DOI: 10.1098/rspb.1996.0043 Spitz, J., Rousseau, Y., & Ridoux, V. (2006). Diet overlap between harbour porpoise and bottlenose dolphin: An argument in favour of interference competition for food? Estuarine, Coastal and Shelf Science, 70 (1-2), 259-270 DOI: 10.1016/j.ecss.2006.04.020 ... Read more »

  • March 24, 2017
  • 07:00 AM
  • 227 views

Friday Fellow: Divergent Dinobryon

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Let’s return once more to the troublesome and neglected protists. This time I’m bringing you another tiny but beautiful alga, more precisely a golden alga. Its name is Dinobryon divergens and as usual there is no common … Continue reading →... Read more »

  • March 21, 2017
  • 10:04 AM
  • 351 views

The Weirdest Animals on Earth: 12 Amazing Facts About Platypuses

by Miss Behavior in The Scorpion and the Frog

What IS that? A photo by Stefan Kraft at Wikimedia Commons.1. Platypuses are so strange, that when British scientists first encountered one, they thought it was a joke: A Governor of New South Wales, Australia, sent a platypus pelt and sketch to British scientists in 1798. Even in their first published scientific description of the species, biologists thought that this duck-beaked, beaver-bodied, web-footed specimen may be some Frankenstein-like creation stitched together as a hoax. But this is only the beginning of their oddities…2. Platypuses are egg-laying mammals. Mammals are animals that have a backbone, are warm-blooded, and females produce milk for their young. Most females that nurse their young also carry their developing babies in their bodies and give birth to live young… But platypuses don’t play by those rules. Platypuses are monotremes, egg-laying mammals that include the platypus and four species of echidna. Most female mammals have two functional ovaries, but female platypuses, like most female birds, only have a functional left ovary. Once a year, a female platypus may produce a clutch of two or three small, leathery eggs (similar to reptile eggs), that develop in her uterus for 28 days. Because female platypuses don’t even have a vagina, when the eggs are ready, she lays them through her cloaca, an opening that serves for reproduction, peeing and pooping. (In fact, monotreme comes from the Greek for “one hole”). She then curls around them and incubates them for another 10 days until they hatch. 3. Platypuses sweat milk! Not only do female platypuses not have vaginas, they don’t have nipples either! Instead, lactating mothers ooze milk from pores in their skin, which pools in grooves on their bellies so the babies can lap it up. …And they’re not even embarrassed about it! 4. Adult platypuses are toothless. Baby platypuses (that is the actual technical term for them, by the way… not “puggles”, which would be way more fun) are born with teeth but they lose them around the time that they leave the breeding burrow. In their place are rigid-edged keratinized pads that they use as grinding plates. When they catch their prey (worms, bugs, shrimp, and even crayfish), they store it in their cheek pouches and carry it to the surface, where they use gravel to crush it in their toothless maw.5. The platypus “duck bill” is a sensory organ used to detect electric fields. Muscles and neurons use electrical impulses to function, and these impulses can be detected by electroreceptors. Although common in shark and ray species, electroreception is rare in mammals, only having been discovered in monotremes and the Guiana dolphin. Platypuses have rows of around 40,000 electroreceptors on their highly sensitive bill, which they wave back and forth in the water, much like a hammerhead shark, to determine the location of their prey. It’s a good thing this sense is so sensitive, since they close their eyes, nose and ears every time they dive. 6. Platypuses don’t use their tails like beavers do. Whereas beavers use their large, flat, leathery tails for swimming and slapping the water to send signals, platypuses don’t use their tails for any of that. Platypuses have large, flat tails for storing fat in case of a food shortage. Unlike beaver tails, platypus tails are covered in fur, which the mothers use to snuggle with their incubating eggs.A platypus ankle spur. Photo by E.Lonnon at Wikimedia Commons.7. Male platypuses have venomous ankle spurs. Their venom is strong enough to kill small animals and to create excruciating pain in humans. Since only males have it and they produce more venom during the breeding season, we think its main function may be to compete for mates and breeding territories.8. Platypuses are knuckle-walkers with a reptilian gait. Although they are well-built for swimming with their webbed feet and legs on the sides of their bodies, these traits make it quite awkward to get around on dry land. To walk, they pull in their webbing and walk on their knuckles, exposing their claws. Like reptiles and salamanders, platypuses flex their spines from side-to-side, supported by their sprawling legs. 9. Platypuses have unusually low body temperatures. As unusual as they are, platypuses are still mammals, which are defined, in part, by their ability to generate most of their own body heat with their metabolism. Platypuses do this as well, but whereas most mammals maintain body temperatures between 37-40 degrees C (99-104 degrees F), platypuses are happy with a body temperature of 32 degrees C (90 degrees F). This lower metabolism reduces the amount of calories they need to eat.10. They have no stomach. Stomachs are specialized protein-digesting chambers of digestive tracts that contain protein-digesting enzymes and acids to activate them. Not all animals have them, but most carnivores do. The most common exceptions to this rule are fish… and platypuses. Why? We don’t know for sure, but many of these animals consume diets high in calcium carbonate, which is a natural antacid. If their own diet would constantly neutralize their stomach acid, then the stomach really isn’t going to do them any good anyway.11. They have 10 sex chromosomes! Most mammals have two sex chromosomes, one from each parent. An individual that has two X chromosomes is usually female and an individual that has one X and one Y chromosome is usually male. Thus, female mammals pass along an X chromosome to each offspring and males can pass along an X or a Y. But platypuses are not content to be normal in any way…They have 10 sex chromosomes: 5 from mom and 5 from dad. All 5 chromosomes from mom are Xs, whereas a male sperm either contains 5 Xs or 5 Ys. Birds also have two sex chromosomes, but in birds, individuals with two of the same type are usually male and individuals with different chromosomes are usually female. Their system is called ZW, where the mammalian system is XY. The platypus X chromosome is more similar than the X chromosome of other mammals to the bird Z chromosome.12. The platypus genome is as much of a hodgepodge as its body. Only 80% of the platypus’ genes are like other mammals. Some of their genes have only previously been found in birds, reptiles, fish, or amphibians.To learn about more weird animals, go here.References: ... Read more »

Scheich, H., Langner, G., Tidemann, C., Coles, R., & Guppy, A. (1986) Electroreception and electrolocation in platypus. Nature, 319(6052), 401-402. DOI: 10.1038/319401a0  

Warren, W., Hillier, L., Marshall Graves, J., Birney, E., Ponting, C., Grützner, F., Belov, K., Miller, W., Clarke, L., Chinwalla, A.... (2008) Genome analysis of the platypus reveals unique signatures of evolution. Nature, 453(7192), 175-183. DOI: 10.1038/nature06936  

  • March 17, 2017
  • 07:00 AM
  • 303 views

Friday Fellow: Pliable Brachionus

by Piter Boll in Earthling Nature

by Piter Kehoma Boll Charles Darwin had already noticed that small animals, such as those found in zooplankton, are widely distributed around the world, even those that are found in small ponds of freshwater. This seemed to go against the … Continue reading →... Read more »

  • March 11, 2017
  • 04:45 PM
  • 312 views

Badass females are unpopular among praying mantids

by Piter Boll in Earthling Nature

by Piter Kehoma Boll One of the most iconic representations of praying mantids is that of a female eating the male after (or during) sex, an unpleasant scenario that starts with a beheading before the poor male even finishes his … Continue reading →... Read more »

  • February 24, 2017
  • 06:18 PM
  • 363 views

Symbiote Separation: Coral Bleaching and Climate Change

by Melissa Chernick in Science Storiented

It’s been a while since I’ve broken down some studies for you, so I took on a big one.I’m sure you’ve heard of coral bleaching. What is it? Why does it happen? Why does it matter? To start off, you need to know a little bit more about the individuals that make up a head (fan, whip, etc.): the polyp. Coral polyps look like tiny plants but are actually tiny animals (less than ½ an inch in diameter). They produce calcium carbonate to create a protective shell or skeleton that, when thousands are living together, make up what you see as a single coral head. Really, only the outer-most layer of a coral head is actually alive (yes, they build their houses on top of the skeletons of their ancestors). Lots of individual corals make up a reef. Polyps have stinging cells (nematocysts) on their tentacles that capture any prey that swims a little too close. But a polyp does not live alone inside of its skeleton-house; it is actually in a symbiotic relationship with dinoflagellates (a.k.a. marine algae) called zooxanthellae (zo-o-zan-THELL-ee). Zooxanthellae live inside the tissues of the coral and photosynthesize, passing some of the energy they make to the polyp. They get a place to live and the polyp gets some energy, it’s a win-win. And, it is the zooxanthellae that give the corals much of their color.When the coral gets stressed, it expels the zooxanthellae, causing them to turn completely white. Not dead, but very stressed and more likely to die. This is coral bleaching.All sorts of things can stress a coral and cause them to eject their zooxanthellae: temperature, light, tides, salinity, or nutrients. A polyp as cemented itself in its skeleton-house so it isn’t able to relocate when conditions change. Coral reefs are one of the most diverse ecosystmes on the planet, definitely in the oceans. Coral is serves as both food and/or shelter for many other species, up to ¼ of all ocean species. And their location means they protect shorelines too. That is a lot of responsibility.Now let’s look at those stressors. Remember middle school chemistry? Yeah, me neither. Here’s a little refresher: water reacts with carbon dioxide to make carbonic acid (H2O + CO2 = H2CO3). Rising atmospheric carbon dioxide (yes, we’re talking climate change here) both increases surface water temperature and water more acidic. That’s two stressors, y’all. And more than 30 percent of human emitted CO2 gets taken up by the oceans. A paper published by Anthony et al. (2008) in PNAS did a nice experiment looking at what happens to coral when the ocean acidifies and/or warms. They collected three of the most important “framework builders” in Heron Reef in the Indo-Pacific and transferred them to lab aquaria: Porolithon onkodes (common crustose coralline algae [CCA] species), Acropora intermedia (a fast growing, branching species), and Porites lobata (a massive species). Next, they used a custom-built CO2 dosing (bubbling) and temperature control system to test different acidification and temperature regimes that simulate doubling and 3- to 4-fold CO2 level increases as projected by the Intergovernmental Panel on Climate Change (IPCC). Then, they waited, they watched, and they took pictures for 8 weeks. From these digital images, they measured the amount of color and reduction in luminance of the corals. They also measured net rates of photosynthesis, respiration, and rates of calcification. They found that increased CO2 (i.e., acidification) led to 40-50 percent bleaching in the Porolithon and A. intermedia. For both of these species, the effect of increased CO2 on bleaching was stronger than the effect of temperature. Porites was less sensitive to increased CO2 alone, but was most sensitive in both stressors. High temperature amplified the bleaching by 10-20 percent in Porolithon and Acropora and 50 percent in Porites. In Porolithon, increased CO2 lead to a severe decline in productivity and calcification that was exacerbated by warming. Acropora’s productivity actually maximized with intermediate increases in CO2, but dropped at higher levels. Porites's productivity dropped with high CO2 but not like that of the Acropora. These species had similar calcification responses to each other, each much less than Porolithon. Overall, the authors proposed that CO2 induces bleaching through its impact on photoprotective mechanisms. Porolithon was the most sensitive to acidification, which is concerning because it is a primary reef-builder and serves as a settlement cue for invertebrate larvae (including other corals).A very recent study by Perry and Morgan (2017) in Scientific Reports zoomed out to look at corals at a large scale. They looked at magnitude of changes that followed the El Niño/Southern Oscillation (ENSO)-induced Sea Surface Temperature (SST) warming anomaly that affected the central Indian Ocean region in mid-2016, sort of a natural experiment. The ENOS-induced SST warming was above the NOAA “bleaching threshold,” defined as the point where SST is 1°C warmer than the highest monthly mean temperature. To do this they went to reefs in the southern Maldivian atoll of Gaafu Dhaalu, ran transects (basically, a line along which you measure stuff), and collected data on coral mortality, substrate composition, reef rugosity (a measure of complexity), and gross carbonate production and erosion. Then they determined carbonate budgets for the 3-dimensional surface of the reefs (there are equations…I won’t go into it…you’re welcome). They found extensive coral mortality over 70 percent. This was mostly driven by branching and tabular Acropora species (remember them from the last study?), which declined by an average of 91 percent! All of this coral death resulted in a decline in the net carbonate budgets. This decline reflected both reduced coral carbonate production and increased erosion by parrotfish as they graze on the algal film that grows on coral rock. Pre-coral bleaching, carbonate production was dominated by branching, corymbose and tabular species of Acropora; post-bleaching production by non-Acropora increased, with massive and sub-massive taxa (e.g., Porites species) more than doubling. Together, carbonate budgets were reduced by an average of 157 percent! All of this equates to a rapid loss in coral cover, growth potential, and structural complexity. The overall impact of the carbonate budget was profound and has major ecological implications. These habitats have gone from a state of strong growth potential to one of net framework erosion and breakdown; basically, the reefs are eroding faster than they are growing. And it may take 10-15 years for a full recovery, depending on the frequency of similar anomalies.So what’s the take-away from all of this? Corals are sensitive to their environment, but not all species of corals respond equally. Climate change is a huge factor in health and recovery of coral reefs, and steps need to be taken soon if we want to keep these little guys and the phenomenal habitats that they create. Here are the studies:... Read more »

  • February 21, 2017
  • 09:02 AM
  • 401 views

Who Can Swim Further: A Race to the Depths and Back (A Guest Post)

by Miss Behavior in The Scorpion and the Frog

By Jefferson LeThe blue whale (Balaenoptera musculus) is the largest mammal on the planet. Image byNMFS Northeast Fisheries Science Center (NOAA) available at Wikimedia Commons.Helloooooo! My name is Bailey and I am a 25 meter long blue whale, the largest living mammal on Earth! My friend Finley, a 21 meter long fin whale comes in second for largest in size. We had an interesting adventure recently where we were followed by humans. While Finley and I were foraging for food, I overheard the humans talking about investigating our diving behavior when we hunt and not hunt. With that, I will tell you what these foreigners did to investigate our behavior and also what happens when we dive. A chart of whales of different sizes. Image by Smithsonian Institute.To record our dives, the humans travelled to Mexican waters to attach recorders onto our mid-backs using a crossbow. Now, it didn’t hurt much due to my thick blubber. These devices recorded depth of how far we dived, time of dives, and our location. These recorders eventually came off between 5 to 13 hours later. Finley and I were not the only test subjects. Other members of our species were also tagged. After all the data on the devices were collected, the humans finally left our waters and did statistical analyses on our diving behavior. The fin whale (Balaenoptera physalus) rarely exposes its fluke when it prepares to diveto the abyss. Image by Aqqa Rosing-Asvid at Wikimedia Commons.Now, before we talk about what the humans found, I want to share with you the whale secret to a great dive. In case that you ever find yourself in the ocean or your local pool, you can try it! The nose for Finley and I are called blowholes, which are found on top of our heads. This tract is separated from our digestive tract so we do not have to worry about having food go down our blowhole. When I am about to dive, instead of gulping in lots of oxygen, I exhale out as much as I can. This causes my lungs to collapse and flexible walls in my chest allow even more compression. Also, tiny structures in my lungs called alveoli collapse which halts any gas exchange. All of the decrease in lung space decreases buoyancy so I can descend down to the depths. As I descend, my heart rate lessens to reduce energy used during the dive. The oxygen that I had obtained before the dive is stored in my blood and muscle tissue. Since the deep depths are really cold, blood flow is temporarily halted at the thinner areas of my body, like flippers, and some organs to keep the main body going. When I ascend back up, I gradually increase space in my lungs and my alveoli regain full function to allow gas exchange. If you were to ascend too quickly, you could get shallow water blackout or even worse, the “bends” (where nitrogen bubbles in your blood) and I heard it is painful. After ascending is complete, I can release my blowhole open and take in fresh oxygen again. I was secretly told what the results to the humans’ experiments were. They found out that fin and blue whales dove deeper when hunting on shallow dives when not hunting. It makes sense! Why spend so much energy diving when not hunting? Also, they noted that our lunge feeding frequency was different. Lunge feeding is where we propel ourselves towards our prey with our mouth open and grab as much food as we can into our mouth. Blue whales lunged about 2.5 times more than fin whales! That’s a point for the blue! However, the record dive depth came from a fin whale. Hmm… I wonder if Finley broke that record. Did you find my secret and what the humans found interesting? I surely did. I never thought about how I dive and how I behave as it is practically in my blood! Well, the next time you are at a deep pool, try those secrets I spilled to you. It might be fun! Then again, you might be thinking, how does a whale communicate with a human and understand scientific data? That is a secret you may never know… Literature Cited:Croll DA, Acevedo-Gutiérrez A, Tershy BR, & Urbán-Ramírez J (2001). The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores? Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, 129 (4), 797-809 PMID: 11440866Hill, R. W., G. A., Wyse, M. Anderson. (2008). Animal Physiology. 2:641-660 ... Read more »

Croll DA, Acevedo-Gutiérrez A, Tershy BR, & Urbán-Ramírez J. (2001) The diving behavior of blue and fin whales: is dive duration shorter than expected based on oxygen stores?. Comparative biochemistry and physiology. Part A, Molecular , 129(4), 797-809. PMID: 11440866  

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