#coral symbiont

[linddzz]

The reddest goddamn M. cavernosa I've ever seen like bro what are you doin what the fuck are your zooxanthellae doin?? Look at that hot fuckin hint of fluorescence around the polyp mouths babygirl calm DOWN

[mindblowingscience]

Vibrio bacteria, named for their vibrating swimming motion, span approximately 150 known species. Most Vibrio live in brackish or salt water, either swimming free or living as pathogens or symbionts in fish, crustaceans, mollusks, and corals. Because Vibrio thrives at relatively high temperatures, outbreaks in marine animals are expected to become ever more frequent under global warming. For example, over the past few decades, Vibrio have been implicated in the 'bleaching' of subtropical and tropical corals around the world. Now, researchers from Spain and Turkey have shown that Vibrio bacteria also play a role in outbreaks of mortality of an unrelated sessile marine organism, the dark stinging sponge (Sarcotragus foetidus). The results are published in Frontiers in Microbiology. "Here we show that pathogenic Vibrio bacteria were abundant in diseased individuals of the dark stinging sponge, during a deadly outbreak first observed in late 2021 in the Aegean Sea," said Dr. Manuel Maldonado, a senior scientist at the Spanish National Research Council (CEAB-CSIC) and a co-author of the study.

Continue Reading.

[coralmorphologic]

A Tale of Two Corals (in the Anthropocene): The past summer’s record hot temperatures were devastating to South Florida’s reefs, wiping out a significant percentage of critically important staghorn corals (Acropora cervicornis aka ACER). Staghorn is a keystone species, and the primary coral grown by restoration practitioners in the Caribbean. They grow fast, but can die a lot faster. 

In 2009 we discovered a unique strain of staghorn coral that had naturally recruited to one of the breakwaters on nearby Fisher Island. Since 2020 we’ve been helping NOAA cultivate fragments of this urban ACER on an experimental nursery adjacent to the Camera. 

In conjunction with University of Miami’s Rescue a Reef program we’ve been using the CCC site to test the resilience of staghorn corals they grow offshore. Like other FL restoration orgs, Rescue a Reef saw many of their outplanted ACER die this past summer. Finding strains that can withstand future heat stress is critical for long term success in restoring our reefs. 

As seen in this 7 month timelapse, a fragment of urban ACER (we’ve dubbed the ‘Ventura’ strain) not only didn’t bleach, but grew at a significant rate. The 2nd staghorn, one of the offshore strains, began strong, but quickly bleached, died, and then was eroded away by parrotfish.  

In early August, UM transported fragments of the ‘Ventura’ strain offshore where the water was cooler for safekeeping. While the ‘Ventura’ strain has proven successful in the nearshore environment, it is important to see how it fares in deeper water before amplifying it for restoration purposes. We are pleased to hear from Rescue a Reef that it is thriving in its new environment! Preliminary analysis of the ‘Ventura’ strain shows it is hosting Durusdinium glynni zooxanthellae, a symbiont known to provide massive corals with thermal tolerance. However, its presence in Caribbean staghorn corals is previously undocumented. Could ACER ‘Ventura’ help restore Miami’s inshore and offshore reefs? Can it confer resilient genetics to future offspring by spawning it in a lab? These are some of the exciting questions we seek to answer in the future!

[wtfearth123]

Did you know that Feather Starfish can regenerate their arms if they lose them? They can also detach their arms voluntarily to escape predators. Some feather starfish even host symbiotic animals like shrimps and crabs. They are amazing creatures that can swim, feed, and breathe with their arms.

Feather starfish are fascinating marine animals that belong to the class Crinoidea, which also includes sea lilies. They are not actually starfish, but they are related to them as they are both echinoderms. Feather starfish have a central body with many arms that are used for swimming, feeding, and respiration. They are usually found in tropical and subtropical waters, where they attach themselves to rocks, corals, or other surfaces. Feather starfish are also known as crinoids or comatulids.

Feather starfish are one of the oldest & most primitive species on earth. Their origins date back to the Ordovician Period, which began more than 488 million years ago. They can have as many as 200 arms, which branch numerous times and result in feathery pinnules. These arms can be of various colors, such as green, red or yellow. They can regenerate their arms if they lose them due to injury or predation. They can also detach their arms voluntarily to escape predators or to reproduce asexually.

Feather starfish host symbiotic animals like shrimps and crabs, which live among their arms and provide protection and cleaning services. Some feather starfish even have specialized structures called cirri that act as claws to hold their symbionts. They feed on planktonic particles that they capture with their tube feet and mucus on their arms. They then move the food along their arms to their mouth, which is located on the upper side of their body.

Feather starfish are amazing creatures that add beauty and diversity to the coral reefs. They are also important indicators of the health of the marine ecosystem, as they are sensitive to environmental changes. I hope you enjoyed reading about this wonderful & beautiful creature. 😊🙏

[o-craven-canto]

Increasing complexity in evolution

Over the history of life there have been many occasions in which new complex systems developed from earlier, simpler ones, leading to explosion in diversity as the new system fills niches that it can exploit better than the old. Some examples are the formation of the first prokaryotic cells from looser collections of genes and membranes, the origin of eukaryotic cells from prokaryotic ancestors, the development of sexual reproduction, the origin of multicellular animals and plants, and the appearance of animal colonies or societies and of complex symbiotic relations.

There are two main types of such complexity transitions, which can be labelled "egalitarian" and "fraternal".

Egalitarian transitions involve the union and cooperation of entities with different origins and abilities. Examples are the combination of self-replicating genes into the coherent genomes of the earliest cells; bacteria and archaea coming together to form eukaryotic cells with mitochondria and sometimes chloroplasts; the origin of societies with non-kin members; mutualist symbiosis between different species, as in lichens; and possibly the union of partners in sexual reproduction.

The defining trait of an egalitarian transition is that the different units are genetically diverse, and therefore must all reproduce on their own: if they didn't all pass on their genes, they wouldn't stay part of the relationship. Even today, in our cells, mitochondria replicate independently of the nucleus. That also means the different units are in competition with each other.

Sure, in the long term cooperation may be best for all: the main driver of egalitarian transitions is cooperation between elements with different "skills", such as the photosynthesis of algae and the talent for nutrient mining of fungi in lichens. But evolution doesn't really do "long term". If an element can replicate itself more by mooching off the others, the mooching variant will become more numerous than the self-effacing variant.

Therefore, the way these transitions occur is by enforcing mutual dependence, for example by enclosure and by synchronized reproduction. When proto-genes were first enclosed by proto-membranes to form proto-cells, they were all in the same boat: any cheater mutant would quickly destroy itself by destroying its own sustainance. Parasites often become beneficial symbionts when they cannot easily jump to a new host, and viruses may become less deadly over time.

The interdependence can be enforced further by exchanging genes: mitochondria and chloroplasts turned over many essential genes to the nucleus of their host cell, and though they can reproduce on their own, they cannot survive for long. Also, mitochondria are only ever passed by the mother's eggs, not by the father's sperm, preventing the zygote from becoming a battleground (in algae, mitochondria always come from one parent, and chloroplasts from the other).

When all goes well, the result of an egalitarian transition is a cell or a society, or a small ecosystem built from cooperating interdependent parts that function as a whole.

In fraternal transitions, in contrast, the units all share the same origin and nature. Examples are the evolution of clonal colonies (e.g. of trees or coral polyps), eusocial colonies (think ants, bees, or naked mole rats), and the origin of animals, plants, and fungi with multicellular bodies. The main benefit here is not complementary skills, but economy of scale: when mole rats dig for tubers, they gain more by sharing the rare but abundant finds than by each digging on their own (and going hungry most of the time).

One major difference from the other type is that all the members of the greater unit are genetically identical, or nearly so: therefore, they do not all need to reproduce (from the POV of my genes, it makes no difference at all whether I or my identical twin have children: any gene I have, they will pass on just as well). Indeed, the disposability of most elements is a selling point of this kind of transition.

But you know who cannot say the same? Cheater mutants -- cancer, if you will. Any cancerous mutation, by virtue of being new, cannot count on being transmitted by other units, and benefits from replicating itself on expense of other genes. The uniform terrain will give it plenty of fertile soil.

An excellent way to put a stop to that is to limit reproduction to few units: think of the egg and sperm cells of animals, or ant queens. First of all, these segregated reproductive units can be kept in conditions that favor a low mutation rate, for example slow metabolism and protection from light. Most importantly, they put a bottleneck through which all mutations must pass: if a cancerous mutation occurs in (say) digestive tissue, that's regrettable, but it won't be passed down to the offspring; but if it happens in the germinal line, well, the new offspring will be entirely composed of cancerous cells, and the bad mutation once again destroys itself. Reproductive segregation resets genetic uniformity in each generation.

Genetic uniformity does not mean morphological or functional uniformity: thanks to contextual gene activation, the cells in your brain, bones, liver, and heart all have the exact same genes, but very different structures and functions. When all goes well, fraternal transitions may end with the constituent units specializing for different functions, taking on some of the advantage of the egalitarian transition, while still keeping genetic diversity as low as possible.

And that's how you go from bacteria to humanity, more or less.

[rjzimmerman]

Excerpt from this EcoWatch story:

After a devastating and hot 2023 summer, the Florida Keys coral restoration community made sure to be prepped for this year’s heat. 

The Florida Keys National Marine Sanctuary (FKNMS) is home to the largest coral barrier reef in the continental United States. In recent years, however, the Florida Reef Tract has suffered a “death of 1,000 cuts” – from water quality issues, pollution and disease. In 2023, a historic marine heat wave caused Florida’s corals to bleach weeks early. 

Bleaching doesn’t always lead to coral death, but it can if conditions don’t improve quickly. “The coral is essentially starving until temperatures lower and symbionts recolonize” within coral tissues, a FKNMS Mission: Iconic Reefs (MIR) fact sheet said. The fact sheet was emailed to EcoWatch during the 2023 heat crisis. Additionally, heat stress makes corals more susceptible to diseases. 

Last year, to beat the heat, coral restoration practitioners took emergency measures and moved what corals they could from their in situ nurseries to land-based holding tanks or deeper water. Many corals were lost, but many were saved, too. Each genetic strain is critical to restoration efforts, so each piece matters. 

“Last year we were caught a bit by surprise and had to react quickly,” said MIR co-lead Jennifer Moore, “but we learned a great deal and are much more prepared this year.”

Florida Institute of Oceanography’s Keys Marine Laboratory (KML) served as a land-based triage station in 2023 for thousands of corals coming in bleached and hot from the scorched ocean. Hosted by the University of South Florida, the scientific research field station held over 5,000 corals in their 60 raceways during the heat crisis. In October and November, once temperatures had dropped and the corals had been checked for general wellness, most of these were returned to the ocean.

This year, as temperatures climb and alarms sound for corals around the world, KML has led the effort to prepare proactively within FKNMS. Using emergency funding, they bolstered the quality of their facilities with additional pop-up shade tents, backup pumps, circulation pumps, spare tank chillers, a new emergency generator, and remote alarms for their seawater systems. This will allow any corals that need to be housed to receive more consistent care at KML. The lab also purchased coral food and cleaning supplies in advance – to be prepared for anything.

KML also hosted a preparedness workshop on site to review seawater systems capabilities and limitations in emergent situations. 

[dan-asd]

Sketch of some vase plants from Deglonia!

They are very similar to animals, but have adapted to house photosynthetic algae in their skin cells. Some common ancestral traits: -They create calcium and iron rich shells around their bodies. -Retracting into their shells to protect their soft body parts. -They have radial symmetry, with many "leaf-tentacles" surrounding an simple pit-gut, that functions like an jar carnivore plant in many species. -Red-orange algae are their original symbionts. The Vase-Plant-Corals (Looking for better name) can vary greatly in individual size and collective colony size, having a few big individuals or lots of centimeter-long individuals together.

[xfang-is-deadx]

I wish I could go on a date to an aquarium but I'd probably end up getting too wrapped up in talking about coral symbionts or something and forget that I need to be doing something romantic

[living-dead-guyy]

what is the stuff on the guys who draw the petroglyphs back

does he have coral or plants or is he just bumpy? Either way very swag

The Snailiens engage in a symbiotic relationship known as mutualism with various organisms. Among these symbionts are species like Feather-Grass Coral, Proboscis Barnacles, and Diamond Barnacles, which I'll elaborate on in a future post. This relationship is advantageous for the Snailiens as the symbiotic organisms consume parasites and dead skin, ensuring the Snailiens' cleanliness and health. In return, the symbionts receive shelter and food, creating a mutually beneficial arrangement :)

[garbage-empress]

It was only a matter of time before I introduced actual nudibranchs to my tank - these two cute little Berghia!

Not all sea slugs are actually nudibranchs, and a lot of people call herbivorous sacoglossans "lettuce nudibranchs," even though they're technically not. All nudibranchs are carnivores, and most are specialized predators that only will eat live prey of a small number of species. They're really cool but most aren't ethical to keep in an aquarium because you can't meet their food requirements. (Doesn't stop dumb or disreputable online vendors from selling "spanish dancer" nudibranchs as algae eaters though.)

Berghia are the exception because they only eat a pest anemone genus called Aiptasia. Aiptasia is essentially ubiquitous and reproduces quickly, so as long as aiptasia is readily available, the Berghia don't starve. Berghia actually can steal the stinging cells out of Aiptasia and use them for defense against predators. They also can steal the Aiptasia's photosynthetic symbionts and eat some of the sugars they synthesize for like a week. My initial plan when I was looking into saltwater aquariums at the beginning of the year was to actually just grow Aiptasia and Berghia, but at the time that seemed daunting and having a tank full of Aiptasia would mean that anything else I put in there risked getting stung to death by the anemones, including coral. Fortunately/unfortunately, my general tank has slowly gotten a decent aiptasia infestation. Which literally from a singular anemone months ago. I'm now setting up a separate little tank to grow Aiptasia in also in case they run out in my main tank. So now I've come full circle.

[102765314]

Marine "Rainforest" - Coral Reefs

Credit: Shaun Low

Introduction

I am Crystal, on a journey to explore mysterious and magical tropical ecology. The theme of my blog is about coral reefs. I choose this because people always say they are important; they are dying now; we must save them. This raises my curiosity to know more about coral reefs. In the exploration of coral reefs, I will share and divide my findings into five entries as follows:

First entry

formation of coral reefs

growing environments

Second entry

Diverse shapes and types of corals

Factors affecting the conformations of corals

Third entry

Feeding behaviour of corals

Reproduction mechanisms

Fourth entry

Ecological relationship between coral reefs and other marine creatures (describe using examples)

Fifth entry

Significance of coral reefs in tropical marine ecosystem

Now, you roughly know what I am going to say about coral reefs. So, let us move on to the first entry.

Coral reefs - Animals or plants?

Credit: Created using Canva

When you dive into the ocean, you are surprised by the beautiful and gorgeous scene at the seabed - the colourful coral reefs. When first looking at corals, you will immediately think they are beautiful plants. Yes, they look very similar to plants but are actually animals. Corals are coelenterates (Goreau, Goreau & Goreau 1979). The phylum's name comes from the Greek words koilos (hollow) and enteron (gut), so corals are hollow guts because their main and long body cavity is the digestive tract (Goreau, Goreau & Goreau 1979).

From corals to coral reefs

Corals are simple and multicellular animals. But how do they grow into the extensive coral reefs we usually find in the ocean? The living, carbonate coral reef system is established from the symbiotic relationship between the reef-building corals and plant-like dinoflagellates (Hoegh-Guldberg 2011). Dinoflagellates are unicellular organism that lives inside the gastrodermal cells of reef-building corals in the order Sclerantinia in the Class Anthozoa and the Phylum Cnidaria (Hoegh-Guldberg 2011). Dinoflagellates are called plant-like because they can perform the unique skill of plants - photosynthesis. In the corals’ gastrodermal cells, dinoflagellates provide a lot of energy from photosynthesis to the coral host (Hoegh-Guldberg 2011). In return, the corals feed dinoflagellates with the metabolized inorganic nutrients, which their quantity is very low in the clear tropical and subtropical marine water (Muscatine et al. 2005).

Credit: Kudela lab group

Credit: Pernice et al.

Fastidious coral reefs

Coral reefs are very picky to the growing environments. They only like ocean water that is sunlit, clear and warm (Goreau, Goreau & Goreau 1979). In addition, they only grow in shallow marine sites at a depth below 100 m and in regions within 30˚ north or south of the equator (Hoegh-Guldberg 2011) because their photosynthetic symbiont requires abundant sunlight. They need clear ocean water because the turbidity can inhibit light penetration (Hoegh-Guldberg 2011). The ocean temperature should be stable and warm (Kleypas et al. 1999). For instance, the ocean temperature cannot fall below 18˚C in places with winter (Kleypas et al. 1999). The growing sites should also contain splendid carbonate ions, which are critical to the calcification of corals (Hoegh-Guldberg 2011). Collectively, coral reefs mainly thrive in shallow equatorial coastal regions because these areas are typically sunlit, warm and supersaturated with carbonate ions.

Credit: Created using Canva

Now, you have an idea of how coral reefs form and what types of environments they like. I have found a nice video that briefly introduces coral reefs. Feel free to watch it if you are interested ^^

Credit: National Geographic

References

Goreau, TF, Goreau, NI & Goreau, TJ 1979, ‘Corals and coral reefs’, Scientific American, vol. 241, no. 2, pp.124-137.

Hoegh-Guldberg, O 1999, ‘Climate change, coral bleaching and the future of the world's coral reefs’, Marine and freshwater research, vol. 50, no. 8, pp. 839-866.

Hoegh-Guldberg, O 2011, ‘Coral reef ecosystems and anthropogenic climate change’, Regional Environmental Change, vol. 11, pp. 215-227.

Kleypas, JA, Buddemeier, RW, Archer, D, Gattuso, JP, Langdon, C & Opdyke, BN 1999, ‘Geochemical consequences of increased atmospheric carbon dioxide on coral reefs’, Science, vol. 284, no. 5411, pp. 118-120.

Muscatine, L, Goiran, C, Lynton, L, Jaubert, J, Cuif, JP & Allemand, D 2005, ‘Stable isotopes (δ13C and δ15N) of organic matrix from coral skeleton’, Proceedings of the National Academy of Sciences, vol. 102, no. 5, pp. 1525-1530.

Reaka-Kudla, ML 1997, ‘The global biodiversity of coral reefs: a comparison with rain forests’, in ML Reaka-Kudla, DE Wilson & EO Wilson (eds),  Biodiversity II: Understanding and Protecting Our Biological Resources, pp. 83-108.

Images or videos from external sources:

Kudela lab group - http://oceandatacenter.ucsc.edu/PhytoGallery/dinos%20vs%20diatoms.html

National Geographic - https://youtu.be/ZiULxLLP32s

Pernice et al. - https://www.nature.com/articles/ismej2011196#Fig1

Shaun Low - https://unsplash.com/photos/v8Un2Roo1Ak

[linddzz]

Tell me about corals magic man

oh man this ask keeps sitting here and I keep starting to write stuff out, forgetting it, then never finishing. So since I am still processing tons of coral pics from a recent field work excursion about coral (and have a day off to just CHILL at home before regular work again) this is as good a time as any. CORAL. IT'S IMPORTANT I GUESS BUT WHAT THE FUCK IS THAT? PLANT?? ANIMAL??? OVERAMBITIOUS ROCK??? Yes. kind of. Technically just an animal is correct. Corals are animals, but they are fucking weird animals. Weird in the way that only marine invertebrates can get. I love them because they're freaks. Let me show you.

Corals are a cnidarian, which puts them in the same category as anemones and jellyfish, and when you look at an individual coral polyp you can instantly see the relationship. They are colonial animals with massive structures formed out of polyps that are all clones of each other, and all building a support structure to form the whole, called the colony. An especially cute metaphor I've heard is that each coral polyp has it's own little nook like a room in the massive home they all work to build. A layer of tissue connects polyps to each other over the colony, allowing them to share nutrients and such over the entire structure like little marine communists. These polyps can range widely in size, and they can either be distinctly separate or all fused together, only distinguished by separate mouths. Numbers can also range from millions to a couple species that will have one or polyp mouths max. Polyps can extend out or retract into their little nook, called the calyx, and extend more when the coral is capturing prey from the water.

Lookit those cute little polyps, these guys make their own cubby for themselves!

Don't worry about what I just said about capturing prey and feeding, look at those cute little guys. Some of them are out and some are retracted, showing the little bump where they live.

Fused polyps like on brain corals don't extend exactly, but feeder tentacles will come out from that delineation between the ridge and oral groove. It's actually called an oral groove! Those tentacles are full of the same stinging cells jellyfish and anemones have! One biologist referred to brain corals as a wall of mouths! Ive seen them using those tentacles to slowly drag struggling little shrimps and larval fish towards a slowly opening mouth amongst that wall of mouths! It's like living in a place where at night, the walls open mouths and drag you into them with unthinking stinging strings! Sometimes they just spit out digestive strings to digest stuff outside of their body, like other coral that got too close and needs to check itself! Isn't that great!

A lot of people are surprised to hear "mouths" and "feeding" with corals and yup, corals are animals and therefore they eat! Each polyp has a mouth and tentacles and will extend them to capture prey, mostly zooplankton but also some plant material. Because they're fucking weird though, many species also gain energy via photosynthesis with the help of a symbiotic dinoflagellate called the zooxanthellae or symbiodinium. It's this algae like symbiont that actually gives coral most of their colors. These colors can range from psychadelic to just brown, with regular old browns and greens and yellows being the most common colors (especially in the Caribbean). A bleached coral is still alive, but due to stress has lost their zooxanthellae. They can survive and recover, but in this state they are highly stressed, prone to disease, and can starve slowly without the symbionts helping with their nutritional needs. They appear white or faded because the loss of their symbionts reveals the white calcium skeleton beneath the tissue.

Bleached portion of coral beside unbleached. A dead coral is one that has lost all of it's tissue, and every individual polyp has died, leaving nothing but the skeleton which can no longer grow without the living polyps. Bleached coral is very, very vulnerable to becoming a dead coral.

Unusually high heat is the most common trigger for a bleaching event. And this is where, in my education talks I sometimes do, I pause with a strained grimace of a smile as we all contemplate ocean temperatures hiking up every summer. SO WHY ARE THESE WEIRDASS ROCK ANIMALS IMPORTANT BESIDES BEING COOL TO LOOK AT? Coral structure can be colloquially described as stony or soft. Stony corals are what I work with more, and these guys are the ones that build a hard, calcium based structure as their support building, and these powerhouses are the ones that build the coral reef. Soft corals are what it says on the tin, they may have a sort of support structure that varies amongst families, but it's flexible (you'll see them waving very beautifully and gracefully in the currents) and they (for the most part) do not build the reef. If they do add to reef building it, it's with a very slow process of depositing fine layers. (Soft corals of course have their role in the overall reef health, but reefs are bonkers complicated ecosystems and I'm trying to keep on track here.) When you're looking at the reef, you are looking on centuries, if not millennia, of stony corals building on top of each other. Sometimes this building has been going on for so long that islands are made of fossilized reefs from millions of years ago, with corals that still resemble modern species in the rock. (This is the case of BonAire and blew my goddamn mind seeing the fossil reef it's so fuckin cool.)

Sometimes just a single colony will keep building on itself into massive structures. Polyp clones adding on and on to their predecessors, giving the colony overall a lifespan in centuries. It's thought that some huge colonies may be thousands of years old, because the fastest growing stony corals have a growth rate that may equal centimeters per year.

It's those reef structures of calcium carbonate building up and up that provide the homes to so many other creatures that coral reefs are some of the most biologically diverse, and biologically dense ecosystems out there, like rainforests of the ocean. Even marine life that doesn't live directly in the reefs have a connection to them, using them as feeding grounds, breeding areas, a place to hide while young and vulnerable, ect. They even protect coastlines, acting as a literal barrier that reduces wave damage from storms or just wave action in general. The reef takes the brunt of the physical damage, colonies get knocked around, but the still living polyps keep on building and rebuilding so the reef can go on and not get smashed into rubble every year. That is, if there are still stony corals alive to do the rebuilding. :))))))

So you have these weird animals who build stone structures like cathedrals, have algae in their tissue, live as massive ancient colonies of clones that can eat, photosynthesize, and also reproduce both asexually and sexually. They're able to branch out and do all of that because they are adapted to insanely stable environments. Temperatures don't fluctuate by more than a couple degrees seasonally, tides are consistent, storm seasons are consistent, the water is consistently clear due to lack of algae, which allows sunlight to penetrate and feed the symbionts that feed the coral. Mineral levels in the water are stable so they can take the calcium and carbonate from the sea water to build their skeletons. Without having to be able to adjust to changes in the environment they just went hog fucking wild on all the ways an animal can be an animal.

And here I once again pause with a strained grimace smile as we all take in how they need to be alive to keep building those reefs that support the ocean and the coasts, and how not stable their environment is becoming with new pollutants clouding waters, storms becoming more unpredictable, and waters having bigger temperature swings with hot summer spikes. :)))))))))))

[aquariuminfobureau]

Our of the animals purchased for their use as biological control in reef aquariums, Mithraculus sculptus is one that has caused a great deal of worry to aquarists. This species is strongly algivorous, and is often purchased for the purpose of algal control. Subsequently the crab gets blamed for damaging corals, and even the deaths of fishes are attributed to the crab. Much confusion exists as to the riskiness versus 'reef safety' of this controversial species. To aquarists this species is known as the emerald crab or simply 'the' mithrax crab. Historically there was much debate about the distinction, or otherwise, of Mithraculus from its relative Mithrax.

Mithraculus is extremely similar to Mithrax, so close overall that observations about the general diet of one genus, also apply to the other. M. sculpta is also known as the green clinging crab in some literature Whatever we call it, this is a crab of the Caribbean and adjacent eastern Atlantic, from Florida and the Bahamas south to Brazil. It grows to about 4 centimeters, or about 1 and a 1/2 inches long.

Although ecological studies tend to stress the herbivory of Mithrax senso lato, both field and laboratory studies of these crabs in the 1970s, have demonstrated their omnivorous feedings, on macroalgae, cnidarians, and detritus. In an experiment, the captive Mithrax eagerly consumed pieces of fish and clam, as well as such marine animals as polychaetes, gastropods, and echinoderms. Mithrax consume Aiptasia anemones, so they are able to consume rather large polyps. The extent of their predation on fleshy polyps and colonies is not known.

Very motile animals such as fish, shrimp, and crabs, were consumed only by scavenging. Mithrax are clumsy foragers, certainly not hunters, and they do not detect prey well, merely consuming animal protein opportunistically. M. sculpta and similar crabs really are primarily herbivorous, although they preferentially take animal derived foodstuffs where they are available. In other words, they have evolved to exploit animal protein if it is encountered whilst feeding on algae. Mithrax crabs are able to extract live snails from their shells, but appear unable to crack hard shelled prey open.

In shallow seagrass beds, and the margins of reef flats, M. sculpta uses the branching, coralline macroalga Neogoniolithon strictum as a host, and the alga benefits from the effectiveness of M. sculpta at controlling epibionts. M. sculpta is also a facultative symbionts of Porites stony corals. The residence of M. sculpta among P. porites, reduces intrusive algal cover on the corals by more than 85%.

Such a statistic is proof of the efficiency of these craps. By day, these crabs shelter in crevices and beneath ledges. Although they are nocturnal, their algal diet restricts them to areas of sunshine. They avoid areas that are shaded during the day, which would impair the growth of their algal food. The claws of M. sculpta are spatulate, an evolutionary tendency among crabs deviating towards herbivorous lifestyles.

In the absence of appropriate algal growth, emerald crabs will consume such foods as nori. They will obviously accept defrosted meaty foods, and some dry preparations. But their natural diet, which is mostly herbivorous, ought to be replicated. Good reason exists to presume M. sculpta is a risk to slow, motile animals like gastropods and starfishes in the aquarium, as well as to large fleshy polyps. But they do not hunt fish, shrimp, or other crabs.

Aquarists should note there is some overlap between the macroalgal genera eaten by emerald crabs, and those purchased deliberately, for ornamental reasons. These crabs are also nocturnal by nature, and many aquarists never see theirs by day, sometimes fearing their pet crab is dead, only to discover the same animal alive, some period later. The species requires places to reside in the rockwork, where it will avoid bright light.

What is reef safety, anyway? A reef is a living ecosystem, and even those organisms that do not consume other organisms directly, are competing for sunlight or space. The idea of 'reef safety' implies a simplification of how organisms in an environment really interact, and is semantically meaningless. It is like saying an animal is 'forest safe' or 'prairie safe'. No one talks about any other biome, the way 'reefers' do about coral reefs.

[jcmarchi]

Seabird Droppings Help Tropical Coral Reefs Facing Climate Change Threat - Technology Org

New Post has been published on https://thedigitalinsider.com/seabird-droppings-help-tropical-coral-reefs-facing-climate-change-threat-technology-org/

Seabird Droppings Help Tropical Coral Reefs Facing Climate Change Threat - Technology Org

A new study, by an international team of scientists, has found the presence of seabirds on islands near to tropical reefs helps corals to ‘bounce back’ much quicker from bleaching events. Bleaching can cause mass die off of corals when seas are too hot.

Corals – illustrative photo. Image credit: Pixabay (Free Pixabay license)

The research, led by Lancaster University, with support from the University of Southampton, shows that this accelerated recovery is a result of faster coral growth near seabird colonies.

The key to how seabirds help tropical coral reefs to grow and recover more quickly is through their droppings. Seabirds feed on fish in the open ocean and then return to islands to roost.

The droppings , called ‘guano’, derived from their fish diet, concentrate nitrogen and phosphorus-rich nutrients from a wider ocean region on the comparably small area of the bird islands. Some of these nutrients enter into the surrounding sea where they act as fertilisers for corals and other marine species.

The Southampton researchers, Dr Loreto Mardones Velozo, Dr Cecilia D’Angelo and Professor Jörg Wiedenmann helped to determine nitrogen-stable isotope values in corals – a reliable measure to trace nutrients derived from guano.

Professor Jörg Wiedenmann, Head of the University of Southampton’s Coral Reef Laboratory, comments: “Our team has recently discovered that corals can access seabird nutrients by feeding on their own symbiont algae. It is exciting to see, in this latest research, how this new nutritional pathway not only helps corals to grow faster, but also to recover from bleaching events.”

The study, published in Science Advances, focused on Acropora, an important type of coral that provides complex structures supporting fish populations and reef growth, as well as protection for coastal areas from waves and storms. Acropora around islands with seabirds were found to recover from bleaching events within approximately three years and eight months, around 10 months faster compared to reefs located close to islands, without seabird colonies, which took four years and six months to regenerate.

The scientists say these shorter recovery times could prove vital in aiding some reefs to bounce back in the face of a warming planet, where damaging bleaching events now occur much more frequently than in earlier decades.

“Our results clearly show that seabird-derived nutrients are directly driving faster coral growth rates and faster recovery rates in Acropora coral,” said Dr Casey Benkwitt, research fellow in coral reef ecology at Lancaster University and lead author of the study.

“This faster recovery may be critical as the average time between successive bleaching events was 5.9 years in 2016 – a reduction from 27 years in the 1980s. Even small reductions in recovery times during this window may be key to maintaining coral cover over the short-term,” she added.

The team’s study focused on a remote archipelago in the Indian Ocean. They compared reefs next to islands with thriving populations of seabirds, such as red-footed boobies, sooty terns and lesser noddies, against reefs next to islands with few seabirds.

The reefs in the study area suffered extensive coral bleaching and mortality following marine heatwaves in 2015-16, providing an opportunity to observe and compare how coral on different reefs recovered. The researchers surveyed the sites from one year before the bleaching event to six years after bleaching, and modelled the Acropora recovery for the years between surveys.

The results showed that seabird-derived nutrients taken up by corals next to ‘bird islands’ boosted coral growth rates – with the rate doubling for each unit of seabird nutrient increase. In contrast, corals near islands infested with rats, causing there to be fewer birds, had similar nutrient values to corals that live at a distance from islands. The additional supply of nutrients to the corals by the seabirds had been virtually cut off by the rats.

The scientists also undertook a coral transplantation experiment to check the results weren’t due to genetic differences in coral populations between different islands. They could confirm it was indeed the presence of seabirds that caused the faster growth. They say their findings add further weight to the growing body of evidence showing ecological damage across ecosystems, on land and sea, from invasive rats on tropical islands.

Professor Nick Graham of Lancaster University and Principal Investigator of the study said: “Combined, these results suggest that eradicating rats and restoring seabird populations could play an important role in re-establishing the natural flows of seabird nutrients to the nearshore marine environment, bolstering rapid coral reef recovery which will be critical as we expect to see more frequent climate disturbances.”

The study, outlined in the paper ‘Seabirds boost coral reef resilience’, was supported by the Bertarelli Foundation as part of the Bertarelli Programme in Marine Science.

Source: University of Southampton

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Adult coral can handle more heat and keep growing thanks to heat-evolved symbionts – The Lifestyle Insider

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Fwd: Postdoc: YorkU_Toronto.Genomics

Begin forwarded message: > From: evoldir@evol.biology.mcmaster.ca > Subject: Postdoc: YorkU_Toronto.Genomics > Date: 1 August 2023 at 06:06:10 BST > To: rdmpage@gmail.com > > > Postdoctoral positions in Ecological Genomics at York University, > Toronto, Canada > > Our group (www.yorku.ca/zayedlab) at York University’s Dept. of > Biology (Toronto, Canada) has positions available for a postdoctoral > fellow in Ecological Genomics with demonstrable expertise in genomics > and bioinformatics for the following two projects: > > 1. BeeCSI: Our group is leading a national Genome Canada-funded >   initiative called BeeCSI (https://beecsi.ca/) to develop stressor- >   specific biomarkers for honey bees. We are looking for a postdoctoral >   fellow with experience in transcriptomics and interest in honey bee >   biology to lead the analysis of a large RNAseq dataset consisting of >   43 laboratory and 12 field experiments where honey bees were >   naturally and experientially exposed to a large number of relevant >   stressors, alone and in combination. The RNAseq datasets have been >   fully assembled and the successful candidate will be able to initiate >   the bioinformatics analyses immediately after starting the position. >   The goal of our research is to characterize the molecular machinery >   underlying the honey bee’s response to multiple stressors, and to >   discover diagnostic transcriptional signatures that can be used to >   predict exposure to stressors in the field. > 2. Genomics of Coral Resilience: A new research direction for the lab! >   The Postdoctoral fellow will use several ‘Omic tools to study the >   genomic basis underlying symbiont shuffling and tolerance to thermal- >   stress in reef-building corals, in collaboration with the Coral >   Resilience Lab at the Hawaiian Institute of Marine Biology. > > Qualified candidates are encouraged to submit a cover letter outlining > their expertise, a CV, reprints of relevant papers, and contact > information for 3 referees to honeybee@yorku.ca. We will evaluate the > applications as they are received, with an application deadline of August > 31st, 2023. > > In addition to the honey bee lab, York University is home to the Center > for Bee Ecology, Evolution and Conservation (BEEc, https://bees.yorku.ca). > Successful candidates will have a chance to interact with the diverse > faculty, fellows and students at BEEc, and participate in BEEc activities > and training initiatives. > > Start Date: Fall 2023 > Salary: Starting from $50,000 and Commensurate with experience. > > > Ida Conflitti