Off California’s Big Sur coastline, a group of scientists have sent a robot to observe sizable cavities in the seabed. But when the team finally receive the results of the investigation, they’re in for a shock. You see, while the robot has indeed detected holes at the bottom of the Pacific Ocean, their precise nature is surprising. And on top of that, it seems that these voids have emerged for a deeply troubling reason.
This particular area of the seafloor has been designated as a pockmark field – a reference to the large dents that define it. It’s been referred to as the largest pockmark field in all of North America, in fact. And while evidence for the cavities apparently first emerged back in 1999, the phenomenon puzzled scientists for many years after.
Over the last decade or so, however, a more concerted attempt has been made to find out more about the pockmarks. And that’s exactly why scientists sent the robot – known as an Autonomous Underwater Vehicle (AUV) – to the seabed. Yet while the aim of this endeavor was to learn about the big cavities, the AUV ultimately revealed something else in the process – and this discovery was concerning, too.
But while some mysteries do still surround this pockmark field, scientists certainly know more about the area than they did two decades ago. This is all largely thanks to the work of the National Oceanic Atmospheric Administration (NOAA) and the Monterey Bay Aquarium Research Institute (MBARI).
The NOAA is actually part of the U.S. Department of Commerce, and its primary purpose is to monitor significant bodies of water. If harsh weather or oceanic conditions are on the way, the agency will also advise on appropriate courses of action. Employees within the administration undertake studies, too.
The MBARI, on the other hand, is a non-profit group that was established by David Packard in 1987. Nowadays, well over 200 people – from scientists to administrators – are said to be involved with the organization, and all are ultimately working towards figuring out ways to better understand the ocean.
Packard has outlined MBARI’s goals, writing in a message on the institute, “The mission of MBARI is to achieve and maintain a position as a world center for advanced research and education in ocean science and technology and to do so through the development of better instruments, systems and methods for scientific research in the deep waters of the ocean. MBARI emphasizes the peer relationship between engineers and scientists as a basic principle of its operation.”
In fact, experts associated with MBARI were the ones to initially notice the indents in the seafloor back in 1999. But two decades on, members of the institute were still interested in learning more about the strange hole. After all, the area has been suggested as a potential site for a wind farm.
According to a 2018 piece by the San Diego Tribune, almost a terawatt of electricity could be created annually off the Californian coast. For comparison, this would amount to about 13 times the total generated by inland wind farms across all of America. So, although offshore wind farming isn’t the only option for producing renewable power, it is an important one.
Nevertheless, there are challenges in taking these facilities offshore. For instance, the seabed in the Pacific is rather erratic, and anchoring a fixed wind farm there could ultimately prove problematic. The U.S. Navy has also vetoed the use of parts of the ocean for wind farms. As such, then, the entirety of California’s southern coastal waters are apparently unworkable.
Yet with so much wind power potentially on offer, the area has nonetheless been studied and surveyed. That’s exactly what the NOAA was doing in 2017 by drawing up a map of the ocean floor near Big Sur. And this work – combined with studies previously undertaken by MBARI – established that the coastal region was home to roughly 5,200 pockmarks spread over 320,000 acres.
Then, in 2018, the experts at MBARI attempted to find out more about the pockmarks littering the Californian seabed. And as a result of this research, it was discovered that these large depressions averaged out at 600 feet wide and 16 feet in depth. They were rounded, too, and separated from each other at fairly regular distances.
Plus, over the course of the recent scientific studies of this underwater region, it’s been noted that there are a particularly large number of pockmarks here – enough to make the field the most important of its kind in North America. So far, you see, scientists haven’t come across any bigger examples.
Still, there are other pockmark fields spread across the globe – and perhaps some undiscovered ones, too. What’s more, specialists have suggested a cause for these dents. It’s been suggested that the indentations may be the result of the venting of gases such as methane from the ocean floor. Such releases could potentially make the bottom of the ocean become unsettled and volatile.
Having said that, MBARI has never actually found explicit evidence to suggest methane was present in Californian coastal waters. In fact, it seems as though the cavities on the Pacific seabed have been dormant for roughly 50,000 years. At least, that’s what information compiled with the use of sonar has suggested to scientists.
So, experts have ultimately struggled to establish exactly what has caused the large pockmarks to emerge. But thanks to modern technology and techniques, there are those who believe they can date the Pacific Ocean examples. According to a senior research technician at MBARI named Eve Lundsten, the cavities are about 400,000 years old.
And while the pockmark field off Big Sur is interesting in its own right, MBARI researchers have since uncovered another intriguing phenomenon in the underwater region. The specialists were only able to make this discovery, moreover, with the help of AUVs.
AUVs are essentially robots designed to journey through water automatically without needing to be directly controlled by a person. They can therefore be utilized by commercial enterprises – companies within the oil industry, for instance – or employed for military purposes. But as we can see from this specific instance, the contraptions are particularly handy for conducting underwater research.
With AUVs’ assistance, then, MBARI scientists were able to observe the pockmark field with a greater degree of clarity. And in doing so, they noticed something surprising: lesser holes in the seabed. These indentations were quite a bit smaller than the neighboring pockmarks, and according to Lundsten they were “completely unique.”
These smaller holes average out at about 35 feet in width and just 3 feet in depth. That said, they appear more frequently than the larger pockmarks – about three times as often. And MBARI researchers have since estimated that there are around 15,000 of these so-called “micro-depressions” in the region.
It’s been posited, moreover, that the micro-depressions formed more recently than the larger pockmarks. And while these indentations may have previously remained hidden, soft material on the seabed being swept away by currents could have revealed them. Perhaps even the movement of sea creatures has had its part to play. Yet this doesn’t quite tell the full story.
Upon observation, you see, it was found that the majority of the micro-depressions were holding pieces of matter – from seaweed and rocks to the remains of dead organisms. And, in particular, a large proportion of the small cavities were housing bits of garbage. This detritus included fishing apparatus, plastic and even a whole bag of decaying waste.
It’s not yet known if this state of affairs is unique to the Californian coast, as other seabeds across the globe may also exhibit similar levels of trash. And one may sadly suspect that they do, as plastic pollution isn’t exactly rare in our oceans.
It seems likely, too, that the trash is at least partly responsible for the creation of these micro-depressions. And although Lundsten and her MBARI colleagues haven’t yet established what the lasting repercussions of the garbage will be, they have seen that sea creatures seem to be making use of the debris.
In many cases, living things do indeed end up making homes in man-made waste or constructions. In sunken vessels, for instance, marine animals have been known to move in and ultimately thrive. And the same, apparently, can be said for abandoned offshore oil platforms – of which there are now many.
Furthermore, in 2014 a study on a concept known as “rigs-to-reefs” appeared in a journal called Proceedings of the National Academy of Sciences. And this paper suggested that abandoned oil platforms in Californian coastal waters can play host to thriving ecosystems – perhaps even the richest ocean environments on Earth.
An example of rigs-to-reefs in action would be in the Gulf of Mexico. There, over 200 oil platforms have stood abandoned for the last three or four decades. And as sea creatures have subsequently moved in, these structures have seemingly become healthy habitats. In fact, fishing is now said to be a booming industry in the region.
However, it would be far too simplistic to suggest that all abandoned oil platforms should host sea life. And a specialist organization known as the Decommissioning Ecology Group said just that in a 2014 letter to the Proceedings of the National Academy of Sciences. The group’s message explained, “Habitat value is only one of many factors that must be considered when making rig-to-reef decisions.”
Yet the Decommissioning Ecology Group’s Ashley Fowler has suggested that the rigs-to-reefs concept has some worth. Speaking to Vice, Fowler said, “Considerable research of platform communities, and their interaction with natural communities, is required to ensure that rigs-to-reefs programs proceed in an ecologically sustainable manner.”
But when it comes to the small trash-made depressions on the Californian seabed, there are still questions that need to be answered – not to mention mysteries that could do with being resolved. After all, as Lundsten has implied, the indents were a complete surprise.
In a statement regarding the discovery, Lundsten explained, “The pockmarks and micro-depressions in this area are both holes in the seafloor that occur in softer sediments. But they are morphologically distinct. The cause and persistence of the pockmarks still remain a mystery, but we find no evidence they were created from gas or fluid in the seafloor in the recent past.”
As we’ve already mentioned, the movement of creatures and currents may have contributed to the creation of the seabed indents. And yet this explanation doesn’t entirely cut the mustard. It’s been suggested, in fact, that this would only account for roughly a third of the depressions on display along the Californian ocean floor.
And Lundsten admitted as much in December 2019, when she discussed the research conducted by MBARI at an event called the Fall Meeting of the American Geophysical Union. There, she gave a presentation related to the work that claimed, “These observations imply that marine trash is at least partly responsible for approximately 4,500 of the 15,000 [holes] and provide some clues as to how the [holes] are created.”
On the MBARI website, Lundsten also elaborated on the theory surrounding the smaller indents. In a statement, she said, “The micro-depressions are recently formed erosional features. They are not ‘incipient pockmarks.’ Overall, a lot more work needs to be done to understand how all these features were formed, and this work is in progress.”
At this point in time, then, it’s not known whether the micro-depressions supposedly created by the garbage will endure. However, if it happens that they do, there’s one potential way to perceive the phenomenon. More specifically, we could take the cavities to be an indication that we’re now in a geological period known as the Anthropocene.
Yes, the lifespan of the Earth is split up into huge stretches of time known as epochs, with some suggesting that we have now slipped into the Anthropocene epoch. Others believe, by contrast, that we are still living in the Holocene era, which commenced roughly 11,650 years ago.
Indeed, there’s even a faction within the scientific community who believe mankind is incapable of driving change to the point of altering the epoch. On the other hand, a number of experts have proposed that the Earth entered into the Anthropocene at the point when mankind learned to light fires, or perhaps further on during the time of European exploration and colonization.
Scientists involved with the Anthropocene Working Group believe, however, that the Anthropocene started in the middle of the 1900s. And if this thesis is widely accepted, it would acknowledge a seismic event in human history. As the Anthropocene Working Group researchers themselves put it in their study, “Not only would this represent the first instance of a new epoch having been witnessed firsthand by advanced societies, [but] it would [also] be one stemming from the consequences of their own doing.”
In their research, the scientists also mention the possibility that we’re now in a period defined by widespread extinction. Yet it’s rather difficult to establish this for certain given the huge stretches of time involved. Indeed, the majority of species that started to thrive in the Holocene epoch are still with us today.
But regardless of precise definitions, the scientific community does appear to widely agree that mankind is affecting the Earth – mostly adversely. And those micro-depressions could in fact give us a clue as to whether we’re now in the Anthropocene era. You see, if the indentations created by garbage along the Californian seabed continue to endure, then this may be a terrifying sign of monumental change to come.