Marine ecosystems are struggling, and mining is set to make it worse.

I was poking around the internet, looking for something to write about, when I came across two research headlines that I think form a depressingly good microcosm of what we’re doing to the planet (and ourselves) as a whole. The first is grim, if unsurprising news; a catchy headline reading, “Multiple ecosystems in hot water“. The study was a 10-year review of California’s Marine Protected Areas (MPAs), which concluded that because of global warming, they aren’t actually helping much. MPAs are, as the name suggests, protected from fishing, industrial activity, tourism, and other activities, depending on the relevant laws. These don’t just protect habitat from destruction, they also serve as a sort of bio-reservoir that can help replenish fish stocks depleted by industrial fishing. The problem is that the absolutely staggering amount of heat that the oceans have been absorbing – equivalent to seven Hiroshima-sized nuclear explosions per second in 2021 – has been making it hard for protected areas to replenish themselves, let alone other nearby habitats.

 As MPA managers around the world face increasing climate shocks, the extent to which MPAs can buffer the worst of these events has become an important question. The working group scientists asked how the ecological communities in California’s protected areas fared after such a severe and prolonged heatwave: Would the communities shift and if so, how? Would they ‘bounce back’ when the marine heatwave subsided? Could the marine protected areas protect sensitive populations or facilitate recovery?

To find answers to their questions, they synthesized over a decade of data collected from 13 no-take MPAs located in a variety of ecosystems along the Central Coast: rocky intertidal zones, kelp forests, shallow and deep rocky reefs. The team looked at fish, invertebrates and seaweed populations inside and outside these areas, using data from before, during and after the heatwave.

They also focused on two of these habitats, rocky intertidal and kelp forests, at 28 MPAs across the full statewide network to gauge whether these locations promoted one particular form of climate resilience — maintaining both population and community structure.

“We used no-take MPAs as a type of comparison to see whether the protected ecological communities fared better to the marine heatwave than places where fishing occurred,” said Smith, now an Ocean Conservation Research Fellow at Monterey Bay Aquarium.

The results are somewhat sobering, though not altogether unexpected.

“The MPAs did not facilitate resistance or recovery across habitats or across communities,” Caselle said. “In the face of this unprecedented marine heatwave, communities did change dramatically in most habitats. But, with one exception, the changes occurred similarly both inside and outside the MPAs. The novelty of this study was that we saw similar results across many different habitats and taxonomic groups, from deepwater to shallow reefs and from fishes to algae.”

The implication of these findings, according to Smith, is that every part of the ocean is under threat from climate change. “MPAs are effective in many of the ways they were designed, but our findings suggest that MPAs alone are not sufficient to buffer the effects of climate change.”

Did we need this study to tell us that? Well, sort of. I think most informed people would have guessed at this result, but it’s good to actually know. We do actually need to check our predictions against reality, and when we find something unexpected, that’s generally a source of new information. This is yet another piece of evidence that climate change is damaging our world right now, and the longer we wait to take that seriously, the less will remain to be saved.

And that brings me to the second piece of research that caught my eye. “Ocean animals vacate areas both around and outside deep-sea mining operations“. A lot of the worries I’ve read about deep-sea mining have related to noise. The sounds from a mine can carry for hundreds of kilometers through the ocean, and with sound being a vitally important tool for marine organisms, that’s a serious issue all by itself. Unfortunately, sound is far from the only problem. Just like its dry-land counterpart, deep-sea mining destroys habitat, and generates a great deal of pollution: .

In 2020, Japan performed the first successful test extracting cobalt crusts from the top of deep-sea mountains to mine cobalt — a mineral used in electric vehicle batteries. Not only do directly mined areas become less habitable for ocean animals, but mining also creates a plume of sediment that can spread through the surrounding water. An investigation on the environmental impact of this first test, published July 14th in the journal Current Biology, reports a decrease in ocean animals both in and around the mining zone.

The International Seabed Authority (ISA), which has authority over seafloor resources outside a given country’s jurisdiction, has yet to finalize a set of deep-sea mining regulations. However, for companies looking to mine the ocean’s floor for minerals such as cobalt, copper, and manganese, the ISA is required to either adopt a set of exploitation regulations or consider mining exploitation under existing international laws starting July 9.

“These data are really important to get out,” says first author Travis Washburn, a benthic ecologist who works closely with the Geological Survey of Japan. “A set of regulations is supposed to be finalized soon, so a lot of these decisions are happening now.”

The team analyzed data from three of Japan’s visits to the Takuyo-Daigo seamount: one month before the mining test, one month after, and one year after. After taking a seven-day boat trip from port, a remotely operated vehicle went to the seafloor and collected video of the impacted areas. One year after the mining test, researchers observed a 43% drop in fish and shrimp density in the areas directly impacted by sediment pollution. However, they also noted a 56% drop in the fish and shrimp density of surrounding areas. While there are several possible explanations for this decrease in fish populations, the team thinks it may be due to the mining test contaminating fish food sources.

The study did not observe a major change in less mobile ocean animals, like coral and sponges. However, the researchers note that this was only after a two-hour test, and coral or sponges could still be impacted by long-term mining operations.

“I had assumed we wouldn’t see any changes because the mining test was so small. They drove the machine for two hours, and the sediment plume only traveled a few hundred meters,” says Washburn. “But it was actually enough to shift things.”

The researchers note that they will need to repeat this study several times to gain a more accurate understanding of how deep-sea mining impacts the ocean floor. Ideally, multiple years of data should be collected before a mining test occurs to account for any natural variation in ocean animal communities.

“We’re going to need more data regardless, but this study highlights one area that needs more focus,” says Washburn. “We’ll have to look at this issue on a wider scale, because these results suggest the impact of deep-sea mining could be even bigger than we think.”

I like to say that we humans are a part of the ecosystems that surround us. We’ve tried to pretend otherwise, but we depend on the “services” they provide to us, and the ocean is no exception to that. My favorite example is the way modern medicine – including every COVID vaccine – relies on the blood of horseshoe crabs, but there are a myriad of other ways in which marine ecosystems help us. There’s the food, obviously; around 20% of the protein humans eat comes from fish, and most of that is from the oceans. As with dry land, marine ecosystems also mitigate pollution, generate oxygen, and provide cultural, aesthetic, and spiritual value to people.

It seems like a problem, then, that we’re just moving ahead with mining the sea floor. I mean, obviously, we’ve been doing seafloor oil drilling for ages, and we definitely need to change how we go about getting cobalt, but as I wrote a couple months ago, we’ll never know the full scale of oceanic biodiversity that we’ve already destroyed. The effects of seafloor mining that we already know about are bad news all by themselves, but when you add in the research about what’s happening to MPAs, more mining could end up being like gasoline on a flame. At a time when global warming is already pushing ecosystems beyond what they can bear, I think that we should be wary of adding more destruction. Rather than mining the sea floor, we should be vastly improving conditions in the mines on land, and investing in better ways to recover things like cobalt from dysfunctional electronics.

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