How anglerfish hack their immune system to hang on to a mate

This article originally appeared in the August/September 2020 issue of the Deep-sea Mining Observer. It is reprinted here with permission. For the latest news and analysis about the development of the deep-sea mining industry, subscribe to DSM Observer here: http://dsmobserver.com/subscribe/

When you live in the darkness of the abyss, finding a partner is hard and keeping a partner is even harder. Deep-sea anglerfish, one of the iconic ambassador species of the deep ocean, have found a novel solution to this problem–dwarf males are sexual parasites that latch onto the body of the much larger female anglerfish and then physically fuse to their partner, becoming permanently attached to the point where they share a circulatory and digestive system. 

Parasitic dwarf males are uncommon, but not unheard of, throughout the animal kingdom. Osedax, the deep sea bone eating worm, also maintains a harem of dwarf males in a specialized chamber in their trunk. But few species, and no other vertebrates, go to quite the extremes of the anglerfish. And with good reason. 

Vertebrate immune systems have a long shared history. The Major Histocompatibility Complex (MHC) is a suite of genes shared among all gnathostomes–the taxonomic group that contains all jawed vertebrates, from fish to fishermen. It creates the proteins which provide the foundation for the adaptive immune system, the core complex which allows bodies to tell self from no-self, detect pathogens, and reject non-self invaders. Suppressing the MHC seriously inhibits a vertebrate’s ability to fight off infection. 

Incidentally, not all deep-sea anglerfish have parasitic dwarf males, and the species most often presented as a type specimen in the popular press, the humpback anglerfish Melanocetus johnsonii, is one of several that do not have permanently attached parasitic dwarf males. M. johnsonii males are free-swimming throughout their life, they’re just small and clingy.

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Emerging technologies for exploration and independent monitoring of seafloor extraction in Areas Beyond National Jurisdiction

[The following is a transcript from a talk I gave at the 2019 Minerals, Materials, and Society Symposium at the University of Delaware in August, 2019. It has been lightly edited for clarity.]

Good afternoon and thank you all for coming. I want to change tracks for a bit and scan the horizon to think about what the future of exploration and monitoring in the high seas might look like because ocean and conservation technology is in the midst of an evolutionary shift in who has access to the tools necessary to observe the deep ocean.

This is the Area. Areas Beyond National Jurisdiction, International Waters, the High Seas, the Outlaw Ocean. It’s the portion of the ocean that falls outside of national EEZs and is held in trust by the UN under the Convention on the Law of the Sea as the Common Heritage of Humankind. It covers 64% of the ocean and nearly half of the total surface of the Earth. It’s also the region in which most major deep-sea mining ventures intend to operate.

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A global assessment of biodiversity and research effort at active Seafloor Massive Sulphides: Transcript from my talk at the International Seabed Authority.

[The following is a transcript from a talk I gave at a side event during Part II of the 25th Session of the International Seabed Authority in July, 2019. It has been lightly edited for clarity.]

I want to change gears this afternoon and talk about a very different kind of mining. For the last two years, Diva and I have been engaged in a data mining project to discover what we can learn and what we still need to learn about biodiversity at hydrothermal vents from the 40-year history of ocean exploration in the deep sea.

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What we’ve missed in the Abyss: Mining 40 years of cruise reports for biodiversity and research effort data from deep-sea hydrothermal vents.

“When the RV Knorr set sail for the Galapagos Rift in 1977, the geologists aboard eagerly anticipated observing a deep-sea hydrothermal vent field for the first time. What they did not expect to find was life—abundant and unlike anything ever seen before. A series of dives aboard the HOV Alvin during that expedition revealed not only deep-sea hydrothermal vents but fields of clams and the towering, bright red tubeworms that would become icons of the deep sea. So unexpected was the discovery of these vibrant ecosystems that the ship carried no biological preservatives. The first specimens from the vent field that would soon be named “Garden of Eden” were fixed in vodka from the scientists’ private reserves.”

Thaler and Amon 2019

In the forty years since that first discovery, hundreds of research expedition ventured into the deep oceans to study and understand the ecology of deep-sea hydrothermal vents. In doing so, they discovered thousands of new species, unraveled the secrets of chemosynthesis, and fundamentally altered our understanding of what it means to be alive on this planet. Now, as deep-sea mining crawls slowly towards production, we must transform those discoveries into conservation and management principles to safeguard the diversity and resilience of life in the deep sea.

Biodiversity of hydrothermal vents from around the world. Top: Indian Ocean, Mid-Atlantic Ridge, Juan de Fuca Ridge. Bottom: East Pacific Rise, Southwest Pacific, Southern Ocean. Photo credits (top left to bottom right): University of Southampton; Woods Hole Oceanographic Institute; Ocean Networks Canada; Woods Hole Oceanographic Institute; Nautilus Minerals; University of Southampton.
Biodiversity of hydrothermal vents from around the world. Top: Indian Ocean, Mid-Atlantic Ridge, Juan de Fuca Ridge. Bottom: East Pacific Rise, Southwest Pacific, Southern Ocean. Photo credits (top left to bottom right): University of Southampton; Woods Hole Oceanographic Institute; Ocean Networks Canada; Woods Hole Oceanographic Institute; Nautilus Minerals; University of Southampton.

Though research at hydrothermal vents looms large in the disciplines of deep-sea science, relative to almost any terrestrial system, they are practically unexplored. Over the last 2 years, Drs. Andrew Thaler and Diva Amon have poured through every available cruise report that made a biological observation at the deep-sea hydrothermal vent to assess how disproportionate research effort shapes or perception of hydrothermal vent ecosystems and impacts how we make management decisions in the wake of a new form of anthropogenic disturbance.

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A big-hearted iron snail is the first deep-sea species to be declared endangered due to seabed mining.

[Note: this article originally appeared on the Deep-sea Mining Observer. It is republished here with permission.]

In 2001, on an expedition to hydrothermal vent fields in the Indian Ocean, researchers made a bizarre discovery. Clustered in small aggregations around the base of a black smoker was an unusual snail, seemingly clad in a suit of armor. Rather than a single, hard, calcareous structure, the snail’s operculum was covered in a series of tough plates. On recovery to the surface, those plates, as well as the snail’s heavy shell, began to rust. This was an Iron Snail.

Individuals from the three known populations of C. squamiferum: Kairei, Longqi, Solitaire (left to right). Chong Chen.
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A polymetallic nodule from the Clarion Clipperton Fracture Zone, purchased from an online dealer. 

Nodules for sale: tracking the origin of polymetallic nodules from the CCZ on the open market. 

[This article originally appeared yesterday in the Deep-sea Mining Observer. ~Ed.]

You can buy a 5-lb bag of polymetallic nodules from the Clarion-Clipperton Fracture Zone on Amazon, right now.

Depending on your vantage point and how long you’ve participated in the deep-sea mining community, this will either come as a huge surprise or be completely unexceptional. Prior to the formation of the International Seabed Authority, there were no international rules governing the extraction of seafloor resources from the high seas. Multiple nations as well as private companies were engaged in exploration to assess the economic viability of extracting polymetallic nodules and tons of material was recovery from the seafloor for research and analysis. Some of that material almost certainly passed into private hands.

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Cut rock samples from the Rio Grande Rise show Fe-Mn crusts (black and gray) growing on various types of iron-rich substrate rocks (pale to dark brown). Photo credit: Kira Mizell, USGS.

A lost continent, rich in cobalt crusts, could create a challenging precedent for mineral extraction in the high seas.

[This article originally appeared yesterday in the Deep-sea Mining Observer. ~Ed.]

The Rio Grande Rise is an almost completely unstudied, geologically intriguing, ecologically mysterious, potential lost continent in the deep south Atlantic. And it also hosts dense cobalt-rich crusts.

The Rio Grande Rise is a region of deep-ocean seamounts roughly the area of Iceland in the southwestern Atlantic. It lies west of the Mid-Atlantic Ridge off the coast of South America and near Brazil’s island territories. As the largest oceanic feature on the South American plate, it straddles two microplates. And yet, like much of the southern Atlantic deep sea, it is relatively under sampled.

Almost nothing is known about the ecology or biodiversity of the Rio Grande Rise.

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All the slime that sticks, we print: 2018 in Hagfish Research

Hagfish. You love them. I love them. Of all the fish in all the seas, none are more magnificent than the hagfish. Across the world, children celebrate the hagfish by making slime from Elmer’s glue, their own mucous, or just, like, something. Seriously, how is is that toddler hands are always coated in some strange, unidentifiable slime?

And never, ever forget:

Your car has just been crushed by hagfish: Frequently Asked Questions.

2018 was a big year in hagfish science. Below are just a few of my favorite studies.

Biogeography

A hagfish in the high Antarctic? Hagfish have previously never been observed in the shallow waters around Antarctic, but a photograph from 1988 was determined this year to be a hagfish feeding on a large pile of clam sperm in shallow water. Neat!

Possible hagfish at 30 m in Salmon Bay in 1988. The white patch is Laternula elliptica sperm.

Incidentally, the reason the photo languished for so long is that it was originally though to be a Nemertean. Because Antarctic Nemertean worms are huge and horrifying.

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Things that go “POP!” in the deep: crushed cups, whole cans, and seafloor spam.

This week, two questions echoed through the hallowed halls of Deep-sea Science. It began, as things these days tend to begin, with a tweet. Dr. Diva Amon challenged deep-sea researchers to show off their shrunken cups from the bottom of the abyss. And we obliged, oh but did we oblige.

Concurrently, though unrelated, Angelo Villagomez announced out symposium on Human Impacts in the Deep Sea and shared several image of the garbage that finds its way to the ocean floor. Cans of cheap beer and pristine Spam littered the deepest reaches of the Mariana Trench, where they will lie forever as they are slowly buried in sediment.

And thus we found ourselves awash in to variations on the same theme: Why did that ocean thing get crushed? and Why didn’t that ocean thing get crushed? Read More