#Oceanography

[chasingrainbowsforever]

~ Marianas Trench ~

[the-briny-bulletin]

Cryptid fish that has only been seen once and never again that may or may not exist but well never know my beloved

[todays-xkcd]

Benthic Santas weren't even discovered until the 1970s, but many scientists now believe Christmas may have originally developed around hydrothermal vents and only later migrated to the surface.

Hydrothermal Vents [Explained]

Transcript Under the Cut

[Top label:] Smoke [Middle label:] Chimneys [Bottom label:] Santas being digested

[Caption below the panel:] Ocean fact: Hydrothermal vent black smokers actually evolved as predatory chimney mimics to feed on benthic Santas.

[todropscience]

DEEP SEA PRODUCE ITS OWN "DARK OXYGEN"

Small metallic nodules, like potato-size strewn across the deep sea ocean seafloor produce oxygen in complete darkness and without any help from living organisms, a new research reveals.

Called polymetallic nodules, are found in the deep sea and produce oxygen through seawater electrolysis, where seawater splits into oxygen and hydrogen in the presence of an electric charge. This charge may come from the difference in electric potential that exists between metal ions within the nodules, which leads to a redistribution of electrons. This is called by scientists as dark oxygen, as is produced without sunlight, as photosintesys does.

-Polymetallic nodules coat fields of the ocean floor Photo: NOAA Office of Ocean Exploration and Research

These nodules polymetallic nodules are common between 3,000 to 6,000 m below the ocean surface. These nodules mostly contain oxides of iron and manganese , but also metals like cobalt, nickel and lithium, as well as rare earth elements such as cerium that are essential components of electronics and low-carbon technologies. This also raise new concerns about potentially mining polymetallic nodules, which could represent a vital source of oxygen for deep-sea ecosystems.

Main photo by Fisheries and Oceans Canada

Reference (Open Access): Sweetman et al., 2024. Evidence of dark oxygen production at the abyssal seafloor. Nat. Geosci.

[reasonsforhope]

"Earth, being 71% covered in water, is influenced by the ocean and its movements. In the Atlantic Ocean, a system of connected currents, called the Atlantic Meridional Overturning Circulation (AMOC), moves water throughout the world's oceans powered by a combination of winds and ocean density. It not only distributes the ocean's heat, moisture, and nutrients, but regulates the Earth's climate and weather.

As the climate is continuously changing and the atmosphere is warming, many scientists fear that fresh water from melting polar ice sheets could significantly disrupt—or collapse—the AMOC. While a decline of the AMOC would have grave consequences, a collapse would be truly catastrophic.

However, studies about the AMOC's long term future are uncertain. Instead of predicting the future, a team of scientists from Woods Hole Oceanographic Institution (WHOI) quantified the past to help inform where we could be going.

In a new paper published in Nature Communications, scientists found that the AMOC has not declined in the last 60 years.

Authors [...] say their results mean that the AMOC is currently more stable than expected.

"Our paper says that the Atlantic overturning has not declined yet," said Foukal, who conducted the research while at WHOI. "That doesn't say anything about its future, but it doesn't appear the anticipated changes have occurred yet."

Their findings contrast with previous work, notably a paper from 2018 cited in their study, which reported that the AMOC has declined over the last 70 years. This past work relied on sea surface temperature measurements to understand how the AMOC has changed, but "we've learned that sea surface temperature doesn't work as well as initially thought," said Terhaar, who began leading this study at WHOI as a postdoctoral scientist and completed the work in Bern.

To address the uncertainty, Terhaar and the team relied on new data from the Coupled Model Intercomparison Project (CMIP), climate-earth models produced by the World Climate Research Program. They used 24 different CMIP models and found that the most recently available surface temperature data did not accurately reconstruct the AMOC.

Going a step further, the researchers looked at a different measure: air-sea heat fluxes, which is the exchange of heat from the ocean to the atmosphere. When the AMOC is stronger, more heat is released from the ocean to the atmosphere over the North Atlantic...

The authors derived this AMOC proxy with the CMIP models, then applied it to observational data. The best data for surface heat fluxes over the North Atlantic come from reanalysis products that incorporate direct observations into a model, similar to the way weather forecasts work. The study authors focused on two reanalysis data sets that extend back to the late 1950s to reconstruct the AMOC.

"Based on the results, the AMOC is more stable than we thought," Vogt said. "This might mean that the AMOC isn't as close to a tipping point as previously suggested." ...

As with all proxy-based reconstructions, there are limitations and caveats. The authors point out that direct measurements of air-sea heat flux going back in time are sparse, and thus the reanalysis products contain significant uncertainty. However, despite these limitations, "a decline in AMOC over the last 60 years," Terhaar concludes, "seems very unlikely.""

-via Phys.org, January 15, 2025

--

Note: Sorry the article's kind of dense/opaque, couldn't find a better one. But I can't underline enough how much "the AMOC is not declining" would be a HUGE relief, climate-wise.

[brtss]

Where I am, mentally.

[strawlessandbraless]

Siphonophore rainbow 🌈

Love to sea it 🌊

[boreal-sea]

THESE ARE NOT PLANTS

I was going put together a cute meme about how seaweed/kelp isn't a plant, it's macroalgae. But to do that, I wanted to show a photo of some ocean life that actually are plants. The problem is that the first two sources that come up when you do a google search for "ocean plants" include multiple kinds of algae, as well as ANEMONES AND CORALS. CORALS AND ANEMONES ARE ANIMALS.

So now, the theme of this post has changed from "Kelp isn't a plant" to:

"NONE OF THESE THINGS ARE PLANTS"

Kelp are a type of macro algae from the Protista kingdom. Protists are not animals, plants or fungi.

Anemone and corals are from the Metazoa sub-kingdom, aka they are animals. They are also not plants. No, not even the corals that host photosynthetic organisms within them - because the zooxanthellae they host are protists, like the kelp.

[humanoidhistory]

Undersea tourists enjoy the view from inside a Gemini submersible's acrylic spheres. Artwork by Jeff Mangiat for Popular Mechanics, October 1988.

[protectoursharks]

Hi! What do you know about the Magnapinna Big fin squid? Is that even it's actual name?

I'm talking about this guy:

Bigfin Squid are AWESOME! They're in the genus Magnapinna which is Latin for "great fin". They're the largest squid species alive today that we know of! They've been recorded to grow around 6 m (20 ft) long and live in depths of up to 6,000 m (20,000 ft)- which is the deepest a squid is known to reside.

There are about three known species of these squid, but most likely more! Even though they're widely distributed across the oceans, they're still difficult to find- only approximately a dozen have been observed. Because they're hard to find and study, there's little we know about them. So, a lot of what we hypothesis is based on what we know of other squid species.

[reality-detective]

Video taken by the diver, who captured an extraordinary moment, it attracted a lot of attention on social media. 🤔

-x@0bendeozledim

[fuckyeahfluiddynamics]

Trapped in a Taylor Column

The world's largest iceberg, A23a, is stuck. It's not beached; there are a thousand meters or more of water beneath it. But thanks to a quirk of the Earth's rotation, combined with underwater topology, A23a is stuck in place, spinning slowly for the foreseeable future.  (Image credit: A23a - D. Fox/BAS, diagram - IBSCO/NASA; via BBC News; submitted by Anne R.) Read the full article

[the-briny-bulletin]

Did you know that 4000 metres bellow the ocean there are chemosynthetic bacteria that are specifically evolved to digest the wood of trees that have grown on land?

The wood on the sea floor can come from trees that fall into lakes and end up in the ocean, or wooden ships that have sunken. (Called 'Wood-falls')

The reason why deep marine organisms are able to digest wood despite never seeing the light of day, let alone a plant - since plants are unable to grow in the deep ocean because of a lack of sunlight - is because the ocean is so isolated and scarce of food that when a new food source is suddenly available, organisms rapidly evolve to be able to eat it.

This is called 'Adaptive Radiation', and can also occur on isolated islands.

[aquatic-dusk]

🌊🌊🌊

[young-american]

[reasonsforhope]

"The world's coral reefs are close to 25 percent larger than we thought. By using satellite images, machine learning and on-ground knowledge from a global network of people living and working on coral reefs, we found an extra 64,000 square kilometers (24,700 square miles) of coral reefs – an area the size of Ireland.

That brings the total size of the planet's shallow reefs (meaning 0-20 meters deep) to 348,000 square kilometers – the size of Germany. This figure represents whole coral reef ecosystems, ranging from sandy-bottomed lagoons with a little coral, to coral rubble flats, to living walls of coral.

Within this 348,000 km² of coral is 80,000 km² where there's a hard bottom – rocks rather than sand. These areas are likely to be home to significant amounts of coral – the places snorkelers and scuba divers most like to visit.

You might wonder why we're finding this out now. Didn't we already know where the world's reefs are?

Previously, we've had to pull data from many different sources, which made it harder to pin down the extent of coral reefs with certainty. But now we have high resolution satellite data covering the entire world – and are able to see reefs as deep as 30 meters down.

Pictured: Geomorphic mapping (left) compared to new reef extent (red shading, right image) in the northern Great Barrier Reef.

[AKA: All the stuff in red on that map is coral reef we did not realize existed!! Coral reefs cover so much more territory than we thought! And that's just one example. (From northern Queensland)]

We coupled this with direct observations and records of coral reefs from over 400 individuals and organizations in countries with coral reefs from all regions, such as the Maldives, Cuba, and Australia.

To produce the maps, we used machine learning techniques to chew through 100 trillion pixels from the Sentinel-2 and Planet Dove CubeSat satellites to make accurate predictions about where coral is – and is not. The team worked with almost 500 researchers and collaborators to make the maps.

The result: the world's first comprehensive map of coral reefs extent, and their composition, produced through the Allen Coral Atlas. [You can see the interactive maps yourself at the link!]

The maps are already proving their worth. Reef management agencies around the world are using them to plan and assess conservation work and threats to reefs."

-via ScienceDirect, February 15, 2024