Category Archives: Sea Creatures

Paleontologists discover new Cambrian age monster

Paleontologists recently unearthed another prehistoric crustacean – a predator with four eyes that lived in the Cambrian age and had a variety of claws with limbs, suggesting that the earliest arthropods may have experimented with the possibilities their limbs had.

The creatures has been identified as Yawunik kootenayi, and it lived about 508 million years ago, towards the end of the Cambrian Period in what geologists have termed the Paleozoic Era. While people generally think of dinosaurs when they think of prehistoric times, Yawunik was around well before them – less time elapsed between the date of your birth and when T-Rex died out, than there is between Yawunik and T-Rex.

Arguably, the animals Yawunik shared the Earth with were more intriguing than the dinosaurs too. It lived in an era when the major classes of animals – fish, insects, amphibians, first began to roam the Earth and the first sophisticated ecosystems began to take hold – an epic period of evolution known as the Cambrian Explosion, largely made possible by the oceans becoming fully oxygenated for the first time as levels of oxygen-absorbing marine bacteria began dying off.

Yawunik was part of a diverse group of shrimp, who shared the ocean with trilobites, spiny sea caterpillars appropriately named hallucigenia, and giant, predatory squid. The fossils bear a slight resemblance to modern crabs, one of its distant relatives, and have been compared to the size and shape of an empanada meat pie (6 inches, or 15 centimeters, long).

The discovery is just a matter of scratching the surface – it’s only the first of several discoveries made within a newly uncovered fossil bed in British Columbia’s Marble Canyon at Kootenay National Park. The Marble Canyon fossil beds were first discovered in 2012, and already may rival British Columbia’s world famous Burgess Shale for its wealth of soft-bodied fossils, preserved in a pristine state, according to scientists.

So far, they’ve found a myriad of Yawunik specimens among the shale, a flaky rock layer that results from layers of compressed mud. Since it was a predator, based on its size, it likely played an important part at the top of the food chain, according to the study’s lead study author Cédric Aria, who is a graduate student of paleontology at the University of Toronto in Canada. Its role may have been akin to the function served by sharks, who are the apex predators of ocean reefs throughout the world.

“We actually found it on the second day [in 2012],” Aria said of the discovery. “It was one of the first really amazing discoveries.”

They named the arthropod Yawunik kootenayi both after the site and for the indigenous Ktunaxa people who long resided in the Kootenay area in which the Marble Canyon excavation site had been found. Yawu’nik in their language meant literally “where the rock stands,” referring to a covenant made between the people and the land in their creation myth.

The new species was first described on Friday in the journal Palaeontology.

Like modern shrimp, the Yawunik is of the group of animals known as leanchoiliid arthropods – a diverse phylum of animals that thrives to this day, making them among the most successful organisms on Earth with the wide variety of climates they have successfully adapted to. Today, they comprise roughly 80 percent of the known species on Earth. Closely related to insects, the phylum consists of shrimp, spiders, scorpions, and the closest modern relative of the trilobite – the horseshoe crab.

In light of these new discoveries, scientists now have yet to completely agree on how and when the basic segmented body and exoskeleton of the arthropod began to evolve – the components most often found in fossils. The reason is that like today’s arthropods, their Cambrian ancestors also had many legs, each set specialized for doing just one particular of any number of activities: whether it’s for eating, swimming, breathing, sensing or even attaching to a mate for reproducing.

A big difference between Yawunik and its modern cousins, however, is its front limbs. They might appear frail, but they were in fact a double threat – long claws which it used to both hunt and to grab onto its prey.

Both frontal limbs consisted of three long claws, two of them had long rows of teeth for trapping and holding onto food, similar to a lobster’s claws. Perhaps the strangest feature were sets of whiplike flagella jutting out of the tips of the claws. Aria suspects that the flagella acted like the front legs of a tarantula, allowing the Yawunik to seek out any passing fish or other organisms nearby, determining first how well they might taste. While Yawunik swam, it swept back and forth against the current with its limbs, which it could retract under its body and spread out when attacking prey.

“This dual function is very, very special, because it does not appear in modern forms.” Aria said. “If you take insects as an example, they have a very constrained body plan. But the constraints were not the same in Yawunik.”

the Yawunik is perhaps most closely related to the modern group chelicerates, which is comprised by spiders, horseshoe crabs and scorpions. This is because the claws are actually rather similar to those of living spiders. However, Aria suspects that this prehistoric beast is more likely part of a stem group, one that broke off of the direct ancestors of modern arthropods.

Since it was discovered back in 1909, over 200,000 fossils so far have been extracted from the Burgess Shale. The Marble Canyon quarry, just 25 miles down the road, could potentially be hiding even more prehistoric creatures and evolutionary links. The sites also date back to the same periods, separated only by 100,000 years – which to geologists is practically the blink of an eye when it comes to rock layers. However, the species found in both spots are vastly different, with the animals found at Marble Canyon more closely representative of creatures excavated at older sites discovered in China and Australia, than they resemble the finds in the Burgess Shale.

“This material is not only so well-preserved but it is so old that we are really tackling immense questions about the origins of modern ecosystems and modern animal groups,” Aria said.

The Royal Ontario Museum has plans to feature the Marble Canyon discoveries in a display currently under construction. Further analysis shows that the fossils actually contain a combination of preserved organic compounds, such as pieces of crustacean shell as well as calcified mineral deposits, which replaced its filaments after it died.

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Fossils of huge plankton-eating sea creature shine light on early arthropod evolution

Arthropods first appear in the fossil record some 530 million years ago. These joint-legged animals are the most species-rich and diverse animal group on Earth. The familiar creatures are virtually ubiquitous: horseshoe crabs, scorpions, spiders, ticks, millipedes and centipedes, crabs, lobsters, pill bugs, butterflies, ants, mosquitos, beetles, and the list goes on.

Note the many body segments of this modern arthropod.
Martin LaBar, CC BY-NC

Arthropods’ unparalleled success is in large part because of the segmented construction of their bodies and limbs. Evolution can separately modify each segment for different purposes, allowing arthropods to adapt to almost every possible environment and mode of life. Modern arthropod limbs in their most basic form have two branches, each of which is often highly specialized for one function – for instance, moving around, sensing the environment, breathing or mating. One of the major questions for paleontologists is how these double-branched limbs evolved.

Our research recently published in Nature focuses on newly discovered fossils of a long-extinct group, the anomalocaridids, to fill in some of the evolutionary story for arthropods.

Anomalocaridids, unknown arthropods

Anomalocaridids first appeared some 530 million years ago, during a geologic period called the Cambrian. The most recent known anomalocaridids date back some 480 million years, and lived during the Ordovician period. To our eyes, these animals look very alien: they have a head with a pair of spiny grasping appendages and a circular mouth surrounded by toothed plates. Their long, segmented bodies carry flaps that were used for swimming.

For decades, the true nature of these animals eluded us, with isolated parts being described as separate animals: their spiny head appendages were believed to be the body of a shrimp, the toothed mouth was considered to represent a jellyfish, and their complete bodies were described as sea cucumbers! It was only in 1985, almost a century after the first anomalocaridid fossils were discovered, that my co-author Derek Briggs together with the late Harry Whittington quite literally put all the pieces together and presented the first accurate reconstructions.

Nevertheless, anomalocaridids remained enigmatic. It would take almost another decade before they were finally recognized as arthropods. Even then, many questions about their anatomy and place in evolution remained. One mystery concerned the nature of the flaps on their bodies: it was believed that anomalocaridids possessed only one set of flaps, and it wasn’t clear to what structure in other arthropods these flaps were equivalent. Another mystery revolved around the apparent complete absence of limbs on their trunk – rather embarrassing for an arthropod! It was generally accepted that, as a result of their swimming lifestyle, anomalocaridids had completely lost their trunk limbs during the course of evolution.

Lateral view of a complete specimen of Aegirocassis benmoulae. Note the presence of two sets of lateral flaps, providing critical new insights into the origins of modern arthropod limbs.
Photograph by Peter Van Roy, Yale University; drawing by Allison C. Daley, University of Oxford., CC BY-NC-ND

New context for anomalocaridid evolution

The recent discovery of exceptionally well preserved three-dimensional fossils of a giant new anomalocaridid tells a different story. Collectors found fossils of the animal – named Aegirocassis benmoulae in honor of its discoverer Mohamed ‘Ou Said’ Ben Moula – in 480 million year old Fezouata Shale deposits in south-eastern Morocco.

Artist’s rendition of the giant filter-feeding anomalocaridid Aegirocassis benmoulae feeding on a plankton cloud.
Marianne Collins, ArtofFact, CC BY-NC-ND

Nowadays the area’s a rocky desert in the Sahara. But when the animal was alive, this area was located close to the South Pole and covered by an ocean. When the animals died, they sank to the sea floor, where their bodies were covered by mud flows. Hard rocks quickly formed around them, shielding the fossils from later geologic upheavals and preserving them in exquisite detail.

Over the millennia, fossils invariably break into smaller pieces that require reassembly in the lab after collection. Often, they’re still partially covered by the surrounding rock. To reveal their full splendor, they need to be carefully prepared, using everything ranging from hammers and chisels, various sizes of dedicated air powered tools to chip away the rock, down to minute needles and fine scalpels. In this case, preparation of all specimens required close to 1,000 hours.

Dorsal view of a complete specimen of Aegirocassis benmoulae.
Peter Van Roy, Yale University, CC BY-NC-ND

During this cleaning process, I discovered that the Moroccan fossils in fact had not one, but two separate sets of flaps per segment. Together with my co-authors Allison Daley and Derek Briggs, we then re-examined other, even older anomalocaridids from the Burgess Shale in Canada. We found that a second set of flaps is also present in other species, but had been overlooked previously. The Moroccan fossils also revealed that ribbon-like structures on the back of the animal, which likely functioned as gills, were connected to the base of the upper flaps and suspended across the trunk.

Relationships of major anomalocaridid groups that preceded modern arthropods. Cross-sections through the bodies show the morphological transitions leading to the double-branched arthropod limb.
Peter Van Roy, Yale University, CC BY-NC-ND

So anomalocaridids did not lose their trunk limbs, as had previously been thought. Rather, their upper flaps are equivalent to the upper branch of the limbs of later arthropods, while their lower flaps correspond to the lower branch and represent modified legs, adapted for swimming. The fact that these structures are still separate in anomalocaridids indicates that classical branched arthropod limbs only arose later, through the fusion of both structures. This confirms that anomalocaridids represent a very early stage in arthropod evolution, before arthropod limbs were all branched.

Detail of the intricate filter-feeding apparatus of Aegirocassis benmoulae.
Peter Van Roy, Yale University, CC BY-NC-ND

The discovery of Aegirocassis benmoulae is also significant from an ecologic point of view. Almost all other anomalocaridids were active beasts of prey which grabbed their quarry with their spiny head limbs. But the Moroccan animal’s head appendages are modified into a very intricate sieve, allowing it to filter plankton from the oceans. Aegirocassis benmoulae attained a massive size of at least up to 7 ft (2.1 m) in length, ranking it among the biggest arthropods to have ever lived. This giant evolved during the early phases of a massive increase in biological diversity, including in plankton. In this way, Aegirocassis benmoulae foreshadows the appearance under comparable conditions of giant filter-feeding sharks and whales in much more recent times.

The Moroccan fossils provide by far the oldest example of massive plankton-eating animals evolving from active predators at the time of a large-scale increase in plankton diversity. They are a prime example of what seems to be an overarching evolutionary trend.

The Conversation

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Leatherback sea turtles use mysterious ‘compass sense’ to migrate hundreds of miles

Imagine yourself swimming in the Sargasso Sea in the Atlantic. The color blue dominates this part of the world – there’s nothing to see but a vast expanse of water and sky in all directions. The winds are calm. The water is warm, clear and deep. You have a destination in mind, but how do you choose your direction, and maintain it, day and night, for thousands of miles? Without a compass or GPS for guidance, this would be an impossible task for a human being. Yet many marine animals routinely achieve this feat during their yearly migrations between breeding and feeding habitats.

Sea turtles are known for their spectacular long-distance migrations. After many years at sea, they can pinpoint their natal nesting beaches after crossing entire ocean basins. We don’t know the distance covered during their developmental journeys but this period can last several decades, and they likely cover tens of thousands of miles. The largest, fastest and deepest-diving species of sea turtle is the leatherback (Dermochelys coriacea). Leatherback sea turtles can grow to over a thousand pounds on a diet of watery jellyfish. They travel extensively between tropical and temperate habitats to gorge on seasonally abundant gelatinous prey. It’s a mystery how they maintain their headings to travel direct migratory paths over such vast distances.

Large Pelagics Research Center scientists collaborate with commercial fishermen to find and tag leatherback turtles at sea. Captain Mark Leach checks out a 800-pound male leatherback turtle with a GPS-linked satellite tag on its back.
Kara Dodge (NMFS Permit #1557-03), CC BY-NC-ND

Satellite tags to track turtles

To understand the behavior and migratory patterns of these enigmatic turtles, we set out to locate and tag them in their northern foraging grounds in the northwest Atlantic. Productive waters off the coast of Massachusetts’ Cape Cod attract a rich diversity of marine life, including the jellyfish-eating leatherback turtle. Working with a skilled team of professionals – including commercial fishermen, a spotter pilot, veterinarians and field biologists – we placed satellite tags on 20 leatherback sea turtles over three years.

Satellite telemetry has revolutionized scientists’ ability to track far-ranging marine animals for relatively long periods of times (months to years), often in otherwise inaccessible habitats. Virtually following animals via tracking tag has provided insight on migration timing and routes of a wide variety of ocean-dwelling species, including sharks, tunas, ocean sunfish, whales, seals, seabirds and sea turtles. Over the last decade, the integration of GPS antennas into traditional satellite tags has greatly improved the accuracy and precision of location data, allowing us to track migrating animals with less error.

In our research off Cape Cod, we used satellite tags that collected location, depth and temperature information. When a turtle surfaces to breathe air, this data is transmitted from the tag to orbiting satellites. Satellites then relay the data to the satellite-based service ARGOS where the data is processed and then, ultimately, it’s sent to us for analysis.

Somehow this young leatherback knows the way.
Kara Dodge (NMFS Permit #1557-03), CC BY-NC-ND

Swimming straight ahead, but how?

One goal of our study was to identify the migratory routes of male and female adult and juvenile leatherback turtles. In our recently published paper in Proceedings of the Royal Society B, we used location data from satellite tags on 15 leatherback turtles to reconstruct their tracks and analyze their migratory orientation as they traveled south to the tropics. They didn’t swim along the coast where they could use landmarks and topographic features on the seafloor to orient themselves. Instead, these turtles struck out for open ocean, swimming offshore into the subtropical gyre. The North Atlantic gyre is a large circle of ocean currents stretching from the equator to near Iceland, and from the east coast of North America to Europe and Africa. We focused our analysis on turtle movements in the middle of the gyre, in an area known as the Sargasso Sea.

Map of leatherback turtle tracks. Segments in the subtropical gyre are highlighted in red (observed) and green (corrected for the effect of currents).

In the deep blue realm of the Sargasso Sea, these turtles were able to maintain remarkably consistent compass headings for over 600 miles (1000 km). Individual turtles followed widely-spaced parallel paths within the gyre. It looked as if the turtles shared the same directional orientation despite being in different parts of the gyre at different times. These consistent headings suggest that leatherback turtles migrating within the gyre use a common compass sense. It remains a mystery just what that compass sense could be.

Within the gyre interior, leatherback turtles have access to limited known sensory information. The seafloor is inaccessible at such depths. Weak ocean currents and lack of stationary reference points make hydrodynamic cues improbable. Wind- or current-borne cues such as odor plumes disperse rapidly over long distances. And sea turtles’ poor eyesight above water likely reduces the utility of celestial cues such as stars. They lack all these bathymetric, hydrodynamic, celestial and chemosensory modes of guidance.

Stay on target, stay on target….
Florida Fish and Wildlife Conservation Commission, NOAA Research Permit #15488, CC BY-NC-ND

Invisibly orienting by solar or magnetic compass

We hypothesize that leatherbacks migrating through the subtropical gyre may orient to some aspect of the earth’s geomagnetic field and/or the position of the sun on the horizon. Leatherbacks could have a time-compensated sun compass, similar to what has been proposed for loggerhead turtles and exists in some birds, butterflies and other animals. These animals orient themselves using the time of day from their circadian clocks and the position, or azimuth, of the sun. Solar and magnetic features are ubiquitous and vary in a predictable way from north to south in this region, making them potentially useful for compass orientation.

Magnetic orientation has been demonstrated in many long-distance migrants, including monarch butterflies, yellowfin tuna, birds, sockeye salmon and sea turtles. In laboratory experiments where leatherback hatchlings were exposed to reversed magnetic field conditions in a darkened room, the turtles oriented in approximately the opposite direction, suggesting they possess a light-independent magnetic compass. If leatherbacks retain this compass into adulthood, it could explain their ability to orient consistently day and night in the gyre. Evidence for a solar compass has also been found in other sea turtles, and leatherback turtles may be able to interchangeably use magnetic and visual (solar) compasses during migration.

Starting out on the journey, baby leatherbacks in Trinidad.
Quinten Questel, CC BY-NC-ND

At this stage, we can only speculate on the importance of different compass senses during leatherback migration. But there’s no doubt that adult and juvenile leatherback turtles are capable of remarkable compass orientation in the seemingly featureless expanse of the Sargasso Sea. How they actually accomplish these feats remains a mystery, but our study provides some tantalizing clues. Future work should focus on understanding the sensory systems that allow leatherbacks, and other ocean navigators, to find their way across the open sea.

The Conversation

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Coral reefs’ physical conditions set biological rules of nature – until people show up

Much ecological literature focuses on the effects that human actions have on species, habitats or ecosystems. Unfortunately, human effects on the natural world are often negative. Whether it’s deforestation, carbon emissions, plastic pollution or industrialized fishing to name a few, humans are having a tremendous impact on the planet.

In the marine world, coral reef ecosystems have received particular attention. Beautiful in color, shape and the diversity of species they harbor, corals have been called the rainforests of the oceans. Corals have also earned the nickname “canaries of the sea” because, like the canaries miners carried underground to warn of noxious gas leaks, they readily respond to changes in environmental conditions, including temperature and light.

Picture perfect, a healthy reef showing high diversity.
Brian Zgliczynski, CC BY-NC-ND

Many scientific investigations have documented direct causal effects of human behaviors on coral reef systems: for example, aggregate mining, land runoff of excessive nutrients, and destructive fishing practices. Few, however, have taken a step back to look at how the presence of humans can affect the natural functioning of coral reef systems as a whole.

What we haven’t known much about is the way environmental factors affect coral reefs in the absence of people. Presumably there are certain physical drivers for how a healthy reef community grows. What natural physical conditions lead to healthy reefs in environments untouched by human beings? What are the natural biophysical relationships in these ecosystems?

A recent study published in the journal Ecography takes a wider view. Rather than identifying a particular negative effect of a certain human activity, the researchers investigated what the natural drivers are for a healthy coral reef ecosystem. With that knowledge, they could then describe how humans alter the way nature works in tropical coral systems.

Research vessel moored off a Pacific island survey site
Brian Zgliczynski, CC BY-NC-ND

Pristine vs populated

The Scripps Institution of Oceanography-based research team, in collaboration with the Coral Reef Ecosystem Division of NOAA in Hawaii, analyzed data from 39 different US-affiliated Pacific islands. Fifteen islands that are home to local human populations served as “impact” test sites. Twenty-four remote and unpopulated islands served as low human impact controls.

Lead author Gareth Williams surveying one of the 39 Pacific island reef sites.
Brian Zgliczynski, CC BY-NC-ND

Using SCUBA and towing specialized camera gear around the circumference of each island, the team documented the corals and algae living on each reef – their so-called benthic communities. In addition, at each island they visited, the team used satellite data to tell them the sea surface temperature, irradiance (a measure of the sun’s brightness), wave energy and level of chlorophyll-a (how productive the water is).

Few, if any, previous studies have been able to document the “natural drivers” of benthic communities on coral reefs because study sites are too often confounded by human impacts. This study is among the first. The team found that a coral community’s composition was determined by the environmental parameters they measured at each site. But this connection held only for the unpopulated, low human-impact sites. Around the people-free islands, environmental measurements explained the benthic cover the team saw. For instance, coral cover peaked in warmer, more productive waters where the magnitude of anomalous wave events was low.

At populated islands, however, the story was quite different. The benthic communities there were not determined by the same natural environmental parameters. At these human-affected islands, the team either saw novel relationships emerge between the benthic communities and the background environment or the ability to explain variation in benthic communities between islands was lost.

A degraded reef at a populated island. The stark reality of human presence… and impact.
Jamison M Gove, CC BY-NC-ND

Decoupling the biological from the physical

At populated islands, benthic communities no longer reflected the natural physical regimes in which they were found. Study leader Gareth Williams and his team termed this “biophysical decoupling” – the natural links between the biological (in this case the benthic cover made up of corals and algae) and the physical (temperature, light, productivity and wave energy) becoming disrupted in the presence of human impacts.

Lifting anchor on the dive vessel after a round-island survey.
Gareth Williams, CC BY-NC-ND

Williams et al. present crucial baselines to identify the drivers of natural variability in coral reef benthic communities across the Pacific in the absence of local human impacts. Such work gives us a glimpse into the forces that structure ecological communities in a world without humans. It also highlights the fact that not all reefs look the same; management targets for coral reef ecosystems therefore must be context specific. Importantly, this research suggests that at populated islands, coral reef benthic communities are not determined by the natural surrounding environment, but by something else: human presence, or at least impacts associated with human presence.

The Conversation

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The private lives of hairy-chested ‘Hoff crabs’

One-and-a-half miles below the icy surface of the Southern Ocean, some of the world’s coldest seawater meets one of the seafloor’s hottest environments, at undersea hot springs – known as hydrothermal vents – on the ocean floor. Recent research in the Journal of Animal Ecology reveals the private lives of “Hoff crabs” – so-called because of their hairy chest – in this remarkable environment.

At this depth there is no sunlight to support life. But a lost world of deep-sea creatures thrives around the undersea hot springs, ultimately nourished by a process called chemosynthesis. Akin to photosynthesis (the process by which plants use energy from sunlight to make food), chemosynthetic bacteria use chemical energy in warm sulfide-rich fluids gushing from the deep-sea vents to build organic molecules, forming the base of the food chain in these environments.

This bacterial bounty supports abundant animal populations around the deep-sea vents, and different species dominate at different distances from the sources of hot fluids, forming patterns similar in scale to those found among animals on rocky shores.

Unlike rocky shores, however, ecologists cannot stroll around deep-sea volcanic vents with ease, and need to use technology such as remotely operated vehicles (ROVs) to investigate patterns of life in these environments.

In 2010, a British research expedition revealed the marine life at deep-sea vents in the Southern Ocean. The species and patterns of life at these vents were different to those previously found at vents elsewhere, such as in the Pacific and Atlantic Oceans.

The zone closest to where hot fluids jet from the vents is dominated by the Hoff crab (belonging to a genus called Kiwa). These crabs bustle in warm waters of around 20°C, with hundreds of crabs per square metre. To survive, they “farm” chemosynthetic bacteria on their chest hairs for food, using comb-like mouthparts to harvest them.

Small female (left); large male (right)
NERC Chesso Consortium

Separation of the sexes

Because of the conflicting demands of feeding and raising young in the conditions at deep-sea vents, male and female crabs lead largely separate lives.

At the base of the mineral spires that form at the vents, males mingle with females in spectacular piles many crabs deep, where they get together to mate. The females then crawl away from the bustling piles of crabs and the warm mineral-rich fluids seeping from the seafloor, which can be toxic to their young.

Away from the mineral spires and warm fluids, the few crabs found are either small juveniles, or females carrying developing offspring under their curled-up tails.

Hundreds of male and female crabs mingle in the warm waters at the base of the chimney
NERC Chesso Consortium

Moving away from the warmer waters of the hydrothermal vents takes the females across a gauntlet of predators, such as large sea anemones and seven-arm seastars. Away from the vents, the cold water of the deep Antarctic also slows down the metabolism of the adult female crabs, making them less active than in the warmer waters of the jostling heaps. However, the conditions away from the vents may be more stable and less harmful to their offspring for their early development, making the journey of the females worthwhile.

For the small juveniles, strength may be found in numbers. These crabs appear to be heading back towards the vents, where conditions are better for gardening bacteria on their hairy chests, providing the food they need to grow. Hundreds of these small individuals were found nestled amongst the piles of larger crabs, fighting together en masse for the warmer sulfide-rich waters provided by the vents.

Males, meanwhile, don’t share in child-care arrangements with the females, and instead can climb up the mineral spires of the vents to take advantage of the warmth and conditions best suited for growing bacteria on their hairy chests – growing much larger than the females as a result.

Deep-sea exploration over the last four decades, including our scientific research cruise to the Southern Ocean, has revealed that undersea vents from different regions of the world’s oceans are dominated by different species of animals, and why we find these differences remains an unanswered question in ecology – but every discovery is another piece in the puzzle.

The Conversation

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Baby sea turtles starved of oxygen by beach microbes

By Vanessa Bezy, University of North Carolina – Chapel Hill

On a small stretch of beach at Ostional in Costa Rica, hundreds of thousands of sea turtles nest simultaneously in events known as arribadas. Because there are so many eggs in the sand, nesting females frequently dig up previously laid nests, leaving the beach littered with broken eggs. But these endangered sea turtles are facing a new threat: sand microbes encouraged by the decomposing eggs.

Results from a new study we’ve published in PLOS ONE show how these sand microbes cause low levels of oxygen in the nests that interfere with the embryonic development of the sea turtles.

Despite the large number of nesting females, hatching success at Ostional beach is particularly low. Scientists have long thought that the problem is due to high microbial activity in the sand caused by the decomposing eggs. In a previous study, we found that nests at Ostional have lower oxygen levels than other sea turtle nests do. This suggested that microbial activity did indeed impact nest oxygen – but it wasn’t until now that this was tested and confirmed. It means that we can now use the results to aid the conservation of these endangered turtle species.

Head in the sand

To understand how microbes affect sea turtle nests, we used different treatments to alter the number of microbes within the nest sand. We monitored nest temperature and oxygen levels throughout the incubation period. We also quantified the number of microbes in the sand and the microbial decomposition of organic matter.

Our results allowed us to look at how all of these factors were associated with sea turtle hatching success. We found that removing and replacing the sand, much like the agricultural practice of tilling, was the most successful treatment for increasing hatching success and decreasing microbial numbers. As we suspected, higher numbers of microbes in the sand were associated with lower hatching success as well as lower oxygen and higher temperatures in the nest.

Essentially, microbial activity in the sand at Ostional beach is so high that microbes are taking up all of the oxygen that the sea turtle embryos need to develop. Additionally, just like a compost pile, the microbial decomposition also increases nest temperatures.

Is it safe to come out yet?
Author provided

Hatching success of sea turtles is a primary conservation concern, given the current threatened and endangered status of these species. In addition to the disruption of nest oxygen levels by microbial activity, human activity above ground also affects hatching success.

Conservation implications

Increasing temperatures due to climate change could increase microbial decomposition rates even more, further impacting sea turtle hatching success. Temperature increase is a particularly important factor because it determines the sex of the sea turtle and high temperatures are also lethal to embryos. Another human impact on sea turtle hatching success comes from the use of fertilisers and beach re-nourishment programmes, which introduce extra organic materials to the beach. These could fuel higher microbial activity, thus also impacting sea turtle hatching success.

While arribadas occur at very few beaches, sea turtle conservation programmes around the world use hatcheries to protect nests from threats such as beach erosion and poaching. These enclosures into which nests are relocated often have problems with microbial infestations, just like those studied in Costa Rica. Our results will therefore help these conservation programmes by providing sand treatment options to manage microbial infestations and increase hatching success.

The Conversation

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Sea creatures will get bigger and bigger (if we don’t eat them first)

By Tom Webb, University of Sheffield

When life on Earth began around 3.6 billion years ago, all organisms were small. Indeed, it took some 2.5 billion years to evolve any organism that grows larger than a single cell.

Since then, things have accelerated a bit and – along with the great diversification of body forms – animals have tended to get bigger. Indeed, the largest animal ever to live, the blue whale, is still very much with us, and has been swimming the world’s oceans for only a couple of million years – a mere blink of the eye in the long, long history of life in the sea.

This trend towards larger body sizes through evolutionary time has become known as Cope’s Rule, after the American palaeontologist Edward Drinker Cope. Cope’s rule has been documented or disputed in hundreds of studies of numerous animal lineages over the last century, but a new study in the journal Science provides perhaps the most comprehensive test yet of its existence.

Sea creatures are getting bigger

The team, led by Noel Heim from Stanford University, delved into the fossil record to compile information on the body sizes of more than 17,000 kinds of marine animals that have existed since the start of the Cambrian period, 542 million years ago. The results are clear: both the average and maximum sizes of marine organisms have increased substantially over this period, whereas the minimum size has remained reasonably constant.

Fossil fan Edward Drinker Cope.

To some extent this may seem inevitable: if life starts small, the only way to go is bigger. And although evolutionary biologists are always wary of narratives of “progress”, many innovations in evolution require a large body size – for example, the smallest vertebrates are inevitably larger than the smallest invertebrates, because it takes a certain size of organism to pack in all the stuff that vertebrates have.

Likewise, warm-blooded marine animals like whales can only stave off hypothermia if they are more than about a metre long. So the re-invasion of the seas by the ancestors of today’s marine mammals imposed a new hard boundary on the minimum size within this group, which in turn affects the average size across groups.

In the new study, Heim and colleagues tested whether the observed increase in size could be explained by a simple evolutionary random walk, where body size is allowed to change randomly at each branching in the tree of life. They also modified this to impose a minimum possible size, such that the evolution of body sizes proceeded randomly but “bounced back” if a lineage hit this lower size limit.

Neither of these models fitted the observed data well. Instead, they show that only persistent directional selection for larger body sizes – due to the many advantages to being large – can explain the observed trends.

Age of the giants

Does this mean that sea creatures are all inexorably getting bigger, and will continue to do so until the oceans are full of behemoths? Not really. First, the minimum size has not changed, and – moving for a moment from evolution to ecology – it is well known that most species are small. In the seas this is especially pronounced, because marine food webs are typically highly size structured – that is, big things eat small things. It takes a lot of small fish to meet the energetic demands of a big fish, and so the only way these food webs can work is if small organisms substantially outnumber their larger predators.

It’s a fish eat fish world.
Pieter Bruegel the Elder, 1556

Second, Heim and colleagues show that most of the overall increase in body size across all marine animals is explained by the evolution of major new groups, with all of the anatomical and physiological innovation that implies. There is rather less of a drive towards larger sizes within any existing group. In fact, many ocean giants are already more or less as big as they could be, given physical and physiological limits.

In their fascinating study Sizing Ocean Giants published in the journal PeerJ earlier this year, marine biologist Craig McClain and colleagues document the factors limiting size in many of the most conspicuous large marine species. These include the risk of tentacle tangling in jellyfish, metabolic constraints on giant clams, physiological limitations of pumping water over gills in large bony fish, or the reliance of blue whales on dense concentrations of their crustacean prey.

In the case of most groups of marine animals, then, it is unlikely that significantly larger members will evolve any time soon. So, even if Cope continues to rule unchallenged, a visitor to our future oceans is less likely to find them populated with fish the size of whales and whales the size of supertankers than with some new giants whose blueprints we do not yet know.

The human factor

However, Cope has an important rival now as an evolutionary force, and that is you, me, and everyone who directly or indirectly exploits our seas. The attitude of people down the ages when confronted with large marine creatures is encapsulated by my reaction when I first saw pictures of newly discovered giant deep sea amphipods: “Barbecue!”.

New species, new food?
Oceanlab, University of Aberdeen

As a species we’ve been pretty effective at removing large animals wherever we roam. As McClain and colleagues say of manta rays (although this is equally applicable to most exploited marine creatures), “In the face of fishing pressure and other anthropogenic threats, it is likely that individuals in many populations may not be near their maximum possible ages or sizes.” In some species, such as plaice and cod, fisheries appear to have driven selection for smaller body sizes, and our evolving understanding of extinction risk in the seas suggests we should not take for granted the continued existence of the ocean’s giants.

Of course, we have been around for too short a time to know if human-driven selection will remain a true competitor to Cope’s rule in the longer term. Indeed, as this new research shows, previous mass extinctions have led to sharp increases in body size among survivors. So who knows? Maybe Cope will again rule the waves following the current human-driven extinction crisis.

The Conversation

This article was originally published on The Conversation.
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Climate Change Could Increase Economic Opportunity Alongside Hostile Conditions at Sea

The future of Earth’s oceans is getting more mysterious and interesting as climate change instigates new and sometimes unforeseen conditions. These changes have already created new opportunities for scientific study, technological advancement, and economic exploitation. Seafaring humans have long been at the forefront of scientific innovation because the sea is such a volatile, ever-changing aspect of the planet to explore. In the coming decades, Earth’s climate will morph into new modes faster than it has in the past, challenging humanity’s most formidable ability: the ability to adapt to new environments. Here’s a look at some nautical situations affected, and how tech is allowing us to adapt to living on the cutting edge between science fiction and often-times bleak meteorological fact.

Dead Water

Dead Water is a sailor’s slang for ocean surface conditions that cause a seemingly-mysterious lag in speed and steering disruption. Melting glaciers release a layer of near-freezing, fresh water into the warmer, salty ocean. Gradually, the freshwater will mix in with the seawater but the temperature and salinity differences cause pools of often times calm, freshwater to float on the surface of the more dense saltwater.

While the effect isn’t always visibly noticeable, a boat can become trapped or experience the sensation of being pulled and pushed around by waves created by disturbing the subsurface saltwater layer. The surface of the water remains calm, yet a boat can lose all control and become unable to resist ocean wave fluctuations taht can’t be seen on the surface at all. If the boat stops in dead water, there is no wake to pull it backward, and there is nothing churning up the deeper saltwater layer – it often seems like there is no current. When the boat tries to move again, the wave pulls it backwards, counter-intuitive to a sailor’s understanding of how wind or engine power should normally propel the boat.  This video really explains it better than words can. Check it out:

Storm Activity Will Affect Shipping and Trade Activity, World Economy

International shipping companies have a lot to lose if they don’t adapt. The adaptation process if often behind where it could be because trade corporations are unwilling to share  proprietary technology regarding safety and ETA projections when planning  and choosing optimum shipping routes. Many of these trade secrets seem to be of dubious cost effectiveness. but are increasing in effectiveness as demand increases. For example: Climatological Ship Resistance (CSR) analyzes the  historical wind and wave data in an attempt to predict conditions, an energy hog of a computer problem that requires additional personnel and training to use but are being used more and more as shipping companies struggle to remain competetive.   Predicting maritime weather is a huge tech industry that is relatively unknown outside the industry. Historically, isolated tech communities aren’t able to grow as fast or efficiently.

The shipping industry is enormous and it’s difficult to interpret the available data but delays, spoiled and lost cargo are all on the rise. Weather conditions can cause crowding at ports, as boats unexpectedly change destinations or show up ahead or behind schedule. A boat ahead of schedule is rare but can actually cause further delays. A currently unfolding drama at the the twin CA ports of Los Angeles and Long Beach where about 40 percent of all imports in the USA show up. Beginning in October of 2014, ships commonly languish offshore for days and weeks while other boats are unloading.


Climate change causes highly elevated levels of CO2 in the ocean which leads to ocean acidification and indirectly or directly threatens every type of edible ocean creature. A great example is the depressingly undeniable case of the shells of young oysters and other calcifying organisms getting thinner and weaker over time as the acidic ocean thins calcium in the shells. UK scientist-in-chief, Sir Mark Walport has warned that the acidity of the oceans is up by about 25% since the the industrial revolution began.

In a recent study, we’ve found most fish not fast enough at adapting to acidification, and humanity should expect to see massive species collapse int he coming decades. Tropical fish and lobstersT are changing locations as they take advantage of warmer sea climates popping up unexpectedly.  Tropical fish might be susceptible to more parasites in hotter water while lobsters overeat,  endangering other habitats and species.

Read more about Climate Change on Cosmoso:

Harvesting electricity from wave and riptide activity

Riptides are amazingly powerful underwater currents. Devices that can withstand deep ocean conditions yet also remain accessible for repairs and upgrades are currently under development and market experimentation. Riptides are particularly appropriate for energy harvesting because they are predictable and consistent. Check out this video to gain a sense of how powerful ocean currents can be.

Wave energy is a renewable resource that is gaining attention as fledgling efforts have had some success. Here’s a great description of the proposed and attempted wave harvesting operations.

Changes to transcontinental, submerged communication fiber-optic lines.

Harsher undersea conditions might make repairing existing internet and phone fiber-optics more complicated but confusing surface conditions can sometimes allow the security to be compromised, as industrial and international espionage operations attempt to hack or sabotage communication lines. On the positive side, thawing polar ocean regions are allowing a previously impossible transoceanic cable to be built. More details about underwater communication cables here.

New examples of climate change are likely to pop up. There are going to be unexpected aspects to Earth’s oceans in the coming years. Preparation and adaptability are crucial in order to properly take advantage of these conditions or protect ourselves from the effects. The smart move for the future economy and world health would be to increase science education and increase funding toward scientific research.

Jonathan Howard
Jonathan is a freelance writer living in Brooklyn, NY

Premiere PBS Series, “EARTH: A New Wild” Looks Dope

Are you sick of nature shows sidestepping environmental disasters and general negative effects humans cause on the species we come into contact with? PBS has always been a mark of quality programming but this new series has me jazzed up for it’s innovative approach to the discussion of human impact on the environment.

EARTH A New Wild questions society’s conventional approach to nature shows by including humankind’s relationship to the natural world as beautiful locations and exotic species are examined with the production values we’ve come to expect from PBS. It’s a new style that is more appropriate to the ongoing environmental discussion of 2015.

The show is a joint production between National Geographic Studios in association with Passion Planet, the series is hosted by Dr. M. Sanjayan, conservation scientist, who takes viewers on a stunning visual journey to explore how humans are inextricably woven into every aspect of the planet’s natural systems.

The series shows humans and the natural environment interacting by editing footage from 45 shoots in 29 different countries. It shows humans in cohabitation with giant pandas, humpback whales, African lions and Arctic reindeer. Dr. Sanjayan posits that humans must learn to work together with animal and plant life in order to survive as a species.

EARTH A New Wild Premieres tonight, February 4th, at 8/9 Central

Jonathan Howard
Jonathan is a freelance writer living in Brooklyn, NY

Jellyfish born in space aren’t happy on Earth

By Rebecca Helm, Brown University

Why send jellyfish to space? Well, because it’s awesome which is true of anything involving space. But mostly because of little crystals that they keep in their bodies, and what these crystals can tell us about long-term human space travel.

When a jellyfish grows, it forms calcium sulfate crystals at the margin of its body (termed a bell). These crystals are surrounded by a little cell pocket, coated in specialised hairs, which are equally spaced around the bell. When jellyfish turn, the crystals roll down with gravity to the bottom of the pocket, moving the cell hairs, which in turn send signals to nerve cells. In this way, jellyfish are able to sense their way up and down. All they need for this to happen is gravity.

Humans have gravity sensing structures too, and therein lies the crux: in space with no gravity, will these structures grow normally? If humans ever want to colonise places in deep space, then we may need to have kids in zero gravity. Will these kids develop normal gravity sensing, even after growing up without it?

For jellyfish, at least, things aren’t so good. After developing in space, these astronaut jellyfish have a hard life back on Earth. While development of the sensory pockets appears normal, many more jellies had trouble getting around once on the planet, including pulsing and movement abnormalities, compared to their Earth-bound counterparts.

Weightlessness, it’s my thing.

Human gravity sensing isn’t exactly like that of jellyfish, but it’s close. The human inner ear contains both fluids and small crystals, which tell us not only the angle of our head, but also our forward momentum. Even with these differences, there is enough similarity between the two systems to be cause for concern. In other words, if jellyfish babies have trouble gravity sensing on Earth after being in space, human babies may be in trouble too.

Human births in space could mean a lifetime of Earthly confusion. Long term space travel will be fraught with developmental challenges to the babies growing onboard. If the jellyfish say growing up in space isn’t so great, we better be listening.

First published on DeepSeaNews.

The Conversation

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