Rosie Alegado

Center for Microbial Oceanography Department of Oceanography & Sea Grant University of Hawaiʻi Mānoa

[typhlonectes]

A Disputed Origin for Eukaryotes

The claimed discovery of a “missing link” in the development of eukaryotes has reignited a thirty-year-old debate.

by Michael Schirber

The eukaryotes are a sophisticated bunch. In their ranks, one finds multi-cellular organisms like animals, plants, and fungi. Even the uni-cellular eukaryotes, such as amoebas and yeast, have an intracellular complexity that far exceeds the simple machinery inside prokaryotes, classified as the “non-eukaryotes.”

Biologists have been debating the origin of eukaryotic complexity for decades, but a study published last year of deep ocean deposits may have uncovered an evolutionary clue within a prokaryote.

In a sample taken from the Arctic Ocean, researchers have identified a microbial organism belonging to the domain of Archaea. What sets this prokaryote apart is that it has genetic markers that put it closer to eukaryotes than any other prokaryote studied before. Moreover, this organism, which has been named Lokiarchaea, appears to have genes that are typically associated with eukaryotic functions, such as membrane remodeling capabilities.

This finding fits into a theory that eukaryotes evolved from an archaeal ancestor, making Lokiarchaeota a kind of “missing link” in the universal tree of life…

(read more: NASA Astrobiology)

images: Centre for Geobiology by R.B. Pedersen  and Williams et al., Nature 504, 231–236 (2013)

[algoriphagus]

A measure that would require the University of Hawai‘i to study the effects of sunscreen on Hawai‘i’s coral reef was passed by the House Ocean, Marine Resources and Hawaiian Affairs Committee on Wednesday.

[algoriphagus]

This program targets full-time students just completing their sophomore or junior year, interested in marine research. Application deadline is February

[algoriphagus]

Anthropogenic litter is present in all marine habitats, from beaches to the most remote points in the oceans. On the seafloor, marine litter, particularly plastic, can accumulate in high densities with deleterious consequences for its inhabitants. Yet, because of the high cost involved with sampling the seafloor, no large-scale assessment of distribution patterns was available to date. Here, we present data on litter distribution and density collected during 588 video and trawl surveys across 32 sites in European waters. We found litter to be present in the deepest areas and at locations as remote from land as the Charlie-Gibbs Fracture Zone across the Mid-Atlantic Ridge. The highest litter density occurs in submarine canyons, whilst the lowest density can be found on continental shelves and on ocean ridges. Plastic was the most prevalent litter item found on the seafloor. Litter from fishing activities (derelict fishing lines and nets) was particularly common on seamounts, banks, mounds and ocean ridges. Our results highlight the extent of the problem and the need for action to prevent increasing accumulation of litter in marine environments.

via Siena Schaar

[amnhnyc]

Symbiosis Explainer

In the latest episode of the web series Shelf Life, we learned about the surprising symbiotic relationship between spotted salamanders and algae. Symbiotic relationships are common in nature, and can take on a wide variety of different forms. While this relationship can play out in many surprising ways, there are three main types of symbiosis seen in nature. Here’s how to tell them apart.

Mutualism: Mutualism is one of nature’s best examples of teamwork. In a mutualistic symbiosis, both parties get something out of the deal and are better equipped for survival because of their arrangement. Take for instance the live sharksucker (Echeneis naucrates), a species of fish that attaches itself to sharks, whales, and other marine animals and keeps them clean by eating smaller parasites. In exchange for its hygienic help, the sharksucker is protected from predators wary of getting too close to its larger hosts.

Commensalism: In commensalism, one species benefits while the other isn’t harmed. In fact, commensal symbiotes can often be overlooked by their hosts. Take for example, Demodex folliculorum, a tiny species of mite found on almost all human faces. These microscopic creatures live out their three-week or so lifespans in your pores and hair follicles. There’s not a lot to recommend them, exactly, but they also don’t bother anyone except in extreme cases, where they can contribute to skin problems. To learn more about the microscopic creatures living in and on your body, visit the special exhibition The Secret World Inside You.

Parasitism: Parasites live off of a host, causing irritation and distress while contributing nothing in return. Blood feeders like the common bedbug (Cimex lectularius) are some of the most easily recognized parasites, but blood is far from the only way they parasites take from their hosts. While it’s not noble, parasitism is an effective way of making a living, so much so that nearly every animal species is the host to at least one kind of parasite. Even parasites themselves host free riders, like the bacterium Wolbachia, which lives in bedbugs, though new research suggests it may play a more complicated symbiotic role than once thought.

Watch the new episode of Shelf Life to see symbiosis in action. 

[amnhnyc]

Each of us has a community of microbes that lives in our digestive system. Scientists call this community our gut microbiome. It plays many important roles in our bodies, like helping to digest food, regulating our immune system, preventing diseases, and even affecting our appetites and our emotions. 

Many things, like what we eat and drink, who we interact with, and the medicines that we take, influence the kinds of microbes that live in our gut. A diverse microbiome is good for our health! Learn more about this topic in the new exhibition, The Secret World Inside You. 

In the new card game, Gutsy, collect microbes, and learn about what helps, and harms, your microbiome. Download the game for free or purchase the deck from the Museum store!

[algoriphagus]

I want!

[micdotcom]

You’d think more than a year after this interaction, people would learn to stop asking female cosmonauts sexist questions. And yet, here we are. Russia is sending an all-female group into space — and not only were they just asked how they’d get by without makeup, but what they’d do without men. They shut it down just as quickly.

[todropscience]

ONE-CELLED PLANKTONIC ORGANISM HAVE ANIMAL-LIKE EYES

Multicellularity is often considered a prerequisite for morphological complexity, as seen in the camera-type eyes found in several groups of animals. A notable exception exists in single-celled eukaryotes called dinoflagellates, some of which have an eye-like ‘ocelloid’ consisting of subcellular analogues to a cornea, lens, iris, and retina

According to a canadian research team at the University of British Columbia, the single celled organism called  warnowiid dinoflagellate evolved a tiny version of a multi-cellular eye. In fact, contains a collection of sub-cellular organelles that look very much like the lens, cornea, iris and retina of multicellular eyes found in large animals.  The ocelloid, who is named the structure, could be used to detect shifts in light as it passed through their transparent prey

This process is known as convergent evolution, when different animals can evolve similar traits in response to their environments.

Warnowiids are found in marine plankton, little is known about their life histories, because they cannot be cultured in the laboratory, and samples obtained from the natural environment do not survive well under laboratory conditions

Light micrograph of a single Warnowia isolate. Scale bar = 10 microns, from Hoppenrath et al. 2009. 

Reference: Gavelis et al. 2015. Eye-like ocelloids are built from different endosymbiotically acquired components Nature

Illustration credit: Gregory S. Gavelis et al. 2015

[algoriphagus]

Article about overfishing.

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#choanoflagellate watercolor: Salpingoeca rosetta #AlegadoLab

[infinity-imagined]

A reminder that the inside of the cell is as beautiful as outer space.

Digital Renders by Evan Ingersoll & Gael McGill

Paintings by David Goodsell

[ecosci]

The Microbe That Invaded Caribbean Coral Reefs

Think of giant pythons from southeast Asia, ending up in the Florida everglades and suffocating any small mammal they could find. Think of cane toads from South America, relentlessly marching over ...

[algoriphagus]

[amnhnyc]

In this episode of Shelf Life, an anthropologist and a computational biologist, joined forces to trace the evolution of Native American languages by applying gene-sequencing methods to historical linguistics.  

Learn more about this episode. 

[algoriphagus]

Love that phylogenetics can be applied to evolution of language

[todropscience]

A JURASSIC PARK OF SPONGE IN THE MEDITERRANEAN SEA

Spanish researchers have published the discovery of a sponge reef unique in the world. These structures, which are thought to be extinct for millions of years, has been found to 760 meters deep, surrounding  small underwater mountain between Valencia and Ibiza, where there is oil drilling plans.

The small seamount is located in an area where there are plans to polls hydrocarbons, and is formed by the species Leiodermatium pfeifferae, sponge so far only known in the Atlantic, from Macaronesia to the Caribbean, so also it is the first report of this species in the Mediterranean.

Silica reefs built by sponges rather than corals were common in the Jurassic and Cretaceous seas, and were believed extinct. To general surprise, in 1987, a live coral silica reef was discovered at 200 m depth in the Canadian Pacific coast, formed by Hexactinellid sponges (“glass sponges”).

The discovery of the reef has been made by a ROV aboard the Oceana Ranger, allowing filming and collecting information on the species associated with this ecosystem, like other sponges, corals, gorgonians, corals deep, conger eels, etc.

Reference (Open Access) Maldonado et al. 2015. Aggregated Clumps of Lithistid Sponges: A Singular, Reef-Like Bathyal Habitat with Relevant Paleontological Connections. PLoS ONE 10(5)

[skunkbear]

From 2009 to 2013, the research schooner Tara traversed the globe, carrying a multinational team of scientists. They surveyed the critical foundation of the marine food chain (a foundation we know dangerously little about): plankton, bacteria, protists, viruses and small animals. All in all, they found more 35,000 different kinds of organisms — many of them previously unknown to science. Read all about it!

Top photo: Tara in the Arctic Ocean (A.Deniaud/Tara Expéditions)

Photo 2: Plankton collected in the Pacific Ocean. (Christian Sardet/CNRS/Tara Expéditions)

Photo 3: A male Sapphirina copepod collected in the Mediterranean sea. (Christian Sardet/CNRS/Sharif Mirshak/Parafilms/Tara Expéditions)

Photo 4: A tiny crustacean copepod, a spider crab larva, an amphipod, a baby squid, a Phronima amphipod, and an Atlantic pteropod mollusc. (Christian Sardet/CNRS/Tara Expéditions)

Photo 5: A small medusa (a relative of the jellyfish) collected in the Mediterranean sea. (bepoles/Tara Expéditions)

Map of the voyage, based on a graphic by bepoles/Tara Expéditions.

[todropscience]

Special issue of Science on PLANKTON   ♥ ♥ ♥ ♥  yay!!