This was by far the most important episode of the series. I am sure that many viewers were troubled by the scale of some of the issues touched upon in the programme; as biological scientists, we live in this state of concern perpetually, both professionally and personally. I tend to see a disconnect amongst the public, that the world we inhabit in our cities and towns are independent of ecological relationships that existed before humans, and now around humans, particularly when it comes to ocean life. In reality, this is not the case. Humans inhabit a unique ecological niche in the history of life on Earth, in that we are the only superpredators ever to regularly predate on the adult forms of other apex predators, in every environment on Earth. There has been talk of considering the era of humans a new geological epoch, defined by extinction, climate change and a stratigraphic layer of plastic for the geologists of the future. Accepting these problems are happening, let alone confronting them, can be depressing. I can’t speak for everyone, but taking a step back, as a scientist, and thinking of these as an interesting series of problems to be understood, is at least how I have decided apply myself to it. Entire books and feature length films have been made on each of the ecological issues in this final episode, so I will only focus on overfishing.

Unlike life on land, which has been drastically modified by humans for as long as we have existed, ocean life has only become heavily exploited more recently (although setting a baseline can be contentious). We have thought of life in the ocean as this resource which will  never be exhausted. Marine biologists have learned in the last few decades that this is not the case. A high profile example is the cod fishery off of Newfoundland, Canada, which was a plentiful food source for 500 years, thought to be the most productive fishery in the world. As fishing technologies improved, more fish could be caught more efficiently and in less time. After regulation failed to curb declines, the cod population completely collapsed in the early 1990s, and has still not recovered. With such a large amount of large predatory cod absent from the ecosystem, a trophic cascade occurred, where smaller fish severely declined and zooplankton, seals and crabs exploded in population. Meanwhile, cod in this area rarely reach adulthood here anymore. Managing the fishery like a resource by considering only population size, and not complex life histories and other ecological relationships, lead to this economic and biological catastrophe.

The wild caught fish that we eat is wildlife, and they shouldn’t be glossed over with the same brush as I sometimes see. Different commercially available fish are as ecologically different to each other as songbirds are to tigers. Tunas for example are apex predators, and although eating tigers, sharks and lions is unusual in the Western world, tuna consumption is extremely widespread. Imagine feeding tiger meat to your cat. Some bluefin tuna can grow to the size of a small car and have endangered or critically endagnered IUCN conservation status (on the same level as the Bengal tiger and black rhinoceros) and yet are still available at most sushi restaurants. There is always talk of ‘dolphin friendly’ tuna, but tuna themselves require urgent conservation as well. Despite improved scientific method, commercial fish species continue to decline worldwide, and faster than estimated.

I am sometimes asked: as a concerned citizen, what can I do in the face of these problems? Honestly, there is no easy answer. Some of the things I would recommend have been suggested a thousand times before, but I will make a few suggestions anyway:

• Only buy what you need. One third of all food is thrown out without being consumed – enough to feed two billion people in a time when one billion are malnourished – a tremendous waste of resources, and your own money. The same applies for all products – for everything you can buy to be produced, finite resources have had to be mined, extensive packaging has been used and goods have been shipped around the world.
• Use less packaging and bottles. 3 billion one-use coffee cups are thrown away in the UK every year, and less than 1% are recycled. This is one cup thrown away in the UK for every person in North and South America, Europe and Africa combined. Get a water bottle, reusable shopping bags and a refillable coffee cup. And is a straw really needed? This is one of the easiest changes to make.
• If you are going to eat seafood, be aware of where it comes from, and what kind of animal you are actually eating. As a general rule, it is better to eat lower down the food chain – sardines, jellyfish and shellfish for instance, and pole and line caught fish minimises bycatch associated with longlines and the habitat destruction associated with trawls. None of this is confidential information – a quick search and you can find plenty of information from the Marine Conservation Society (they even have iOS and Android apps) about where different species come from and how they are caught.
• Similarly, different foods require different resources. As a general rule, a diet with the least amount of environmental impact consists primarily of fruits, vegetables and grains and little or no meat. And if you can, buy produce that has not travelled a long way – less air miles, and less wastage from spoilage during long transits. See video below.
• Above all else, understand these issues – to me, this takes away their overwhelming amorphous terror. Start by learning about the human species in context. I cannnot recommend Elizabeth Kolbert’s incredible Pulitzer-winning The Sixth Extinction  enough, as a highly readable introduction to the concept. She interviews scientists watching their life’s work go extinct, visits an island made of bleached coral on the Great Barrier Reef and talks about how perceptions take a generation or so to change. Those more interested in marine life specifically should try Callum Roberts’ The Unnatural History of the Sea, who meticulously ploughs through archaic records from early fishermen, pirates and explorers to set a new baseline for human impacts on the ocean.

Despite grave threats facing the ocean, life is remarkably resilient, and where beneficial alternatives are provided, there are success stories. Despite resistance from the fishing industry, no-take zones like those in New Zealand have proved highly successful at restoring fully mature fish and species not seen in decades, protecting biodiversity and then being available for fishing as well. For us, the four-year Blue Belt plan aims to protect 4 million square kilometres of marine habitat, an area larger than India, across 7 UK Overseas Territories. Ultimately, getting business to prioritise conservation, and large scale international cooperation on legislation are ultimate goals, but these large scale changes always begin with small groups of scientist, campaigners and passionate citizens. Some of this has come from our university. If you can convince your place of work to waste less food or use less plastic, then why not do it? You can also go here to check if your local MP is on board with the Blue Belt plan, and contact them to tell them to vote in its favour. As a country with the fifth largest area of marine habitat in its jurisdiction, having this go through UK parliament would be globally significant.

The public engagement from this new Blue Planet series has been extremely heartening. It was so popular in China that it slowed down the internet there, and is the third most watched series of the last five years. I look forward to seeing what people inspired by the series will do in the future.

Feel free to ask me any further questions on Twitter @kieranyes.

The post Blue Planet 2 | Episode 7 | Our Blue Planet appeared first on Exploring our Oceans .

We have a tendency to take our coastlines for granted. It is by far the most accessible and relatable marine habitat, with thousands flocking there every day for their primary source of food, watersports, or just to relax. The UN estimates 40% of the world’s population live in coastal areas. They provide the most extensive economic and social benefits of any natural habitat, encompassing 77% of the services provided to us by all ecosystems. It is where most of us began our love for the sea. In the UK, you are never more than 70 miles away from it. Yet it is easy to forget it is a place of extremes, and as important as any other marine habitat.

Coastal species have to endure excruciating changes in their environment twice a day. Marine animals can be categorised based on their preferences and adaptability to two primary conditions: temperature and salinity (‘saltiness’). A change in salt might be nothing to one of us as we are osmoregulators (we regulate our internal environment) – for an osmoconformer, like a sea cucumber or starfish, this can be devastating. Too little salt, and your internal water diffuses out, and too much, and outside water will pass in until your cells burst. In the ocean, these conditions remain relatively stable – you can assume that they are unlikely to change dramatically in the next few metres, or few hours. However, if you live in the intertidal zone, you are likely to be bombarded with really hot temperatures at low tide, dramatic changes in salinity if you live in an estuary or at a river mouth, and running out of oxygen if you are caught in a rockpool. To make matters worse, the coast itself is constantly shifting, as shown in the programme. You have to be very hardy and resilient to live here.

Coastal management is a huge challenge anywhere in the world – there is always a trade off between using the coastline for economic and recreational ventures, but not at the sacrifice of the coast’s ecology and longevity. Although only covering 20% of the Earth’s surface, 41% of the world’s population are coastal inhabitants. For example Guyana, a country larger than the UK, 90% of its population lives on a narrow coastal plane, and only a narrow sea wall protects its inhabitants from the ocean. 21 of the world’s 33 megacities are found on the coast, including Tokyo, Lagos, New York and Buenos Aires. With a globally increasing population, how do we ensure coastlines are sustainably developed and not overxploited?

I have noticed that the UK’s coastlines are a severely underrated habitat among many wildlife enthusiasts. Since the establishment of Lundy Island as the first MCZ (Marine Conservation Zone) in January 2010, a total of 50 sites now make up an area the same size as Wales. These are designated to protect rare and threatened species, and also the wide diversity of life found here. We were lucky enough to conduct some camera drop surveys of the maerl beds of the Fal Special Area of Conservation – a red calcareous algae, superficially similar to corals – of which the UK has in several locations. Maerl can be up to 8000 years old, and provide habitat for rare species like Couch’s goby, much like coral reefs do in the tropics. Additionally mudflats, estuaries and sandbanks are not the most glamorous marine habitats but have still been highlighted for conservation as part of global efforts to conserve biodiversity. Just as an example to the importance of this Blue Belt initiative, seagulls are a red list species in the UK due to their overall declines across the country due to habitat loss. This will come as a surprise to many. They are widely considered pests as they have been increasing in urban areas, partly because of abundant food, and partly because they have nowhere else to go.

Appreciating and conserving the marine environment does not just encompass tropical coral reefs, the great whales of the open ocean and the polar ice caps that many of us will only ever admire through a screen. Declines in biodiversity are all-encompassing and are essential for the future of habitats, and ultimately, our own wellbeing. We in the UK are just as responsible for protecting our marine species as any other country, and you don’t have to fly to the tropics to be close to the Blue Planet.

The post Blue Planet 2 | Episode 6 | Coasts appeared first on Exploring our Oceans .

Whilst studying at the University of Southampton, I’ve learned a lot about the ecology of our coasts, specifically that of sandy and rocky shores. During a field course to the Dale Peninsula in West Wales, we explored the challenges that coastal fauna face on a daily and seasonal basis – over-exposure to heat in rockpools during the ebbing tide forces crabs and other coastal invertebrates to take shelter under seaweed like bladderwrack; the high wave action of exposed shores can be rewarding in terms of food and oxygen supply, but also risky for animals without top adhesive properties; and the race for space in a competitive rocky shore environment leaves a distinctive, territorial pattern of limpet home-ranges across each boulder. During this week’s episode, expect to see similar stories of the daily life-and-death struggle of coastal animals, specifically those that live along diverse rocky shores and in vibrant rock pools; and, of course, lots of gorgeous time-lapse footage.

Since the coast forms such an important oasis for seabirds like puffins, sanderlings and penguins, I believe that the lives of seabirds will feature heavily in this episode. Penguins are obviously a fan-favourite, but the heartbreaking sequence on wandering albatrosses in Big Blue captured the public’s imagination too. Puffins are also marvellous birds, with incredibly strong wills – they must travel for miles to find food to feed their young that nest along the clifftops of the coast, dealing with challenges like battering weather and competition from other seabirds along the way. However, puffin populations are in danger, with many fledgelings suffering from starvation due to shifting fish populations and resultantly increased competition (yet another impact of a warming climate). Expect to see some seabird family drama in this weeks episode!

Coasts are also the closest and most accessible marine environment for us as humans – in the UK, you are never more than 70 miles from the sea. We have a close connection with our coasts, both socially and economically – many of us visit the beach regularly for surfing, sunbathing and rockpooling, but coasts around the world are also lined with industrial ports and fisheries. This human element of the coast is likely to be highlighted during the episode, most probably continuing the pattern of displaying human impact on the wildlife. Expect to see a sequence much like that seen in the final episode of Planet Earth 2, Cities, where the tragic story of light pollution impacts on Hawksbill turtle hatchlings unfolded.

Feel free to share any comments or questions regarding Coasts – I hope you enjoy the episode!

Inspired by the episode? Help us clean up our coasts!

The post What to expect from Blue Planet 2 – Coasts appeared first on Exploring our Oceans .

Huge shoals of plankton move from the deep sea and back every day as the sun rises and sets. There are massive migrations of small fish and squid that follow them to exploit this resource, as well as larger predators which hunt them. This enormous movement of biomass from the deep sea to surface and back happens every single day.

Despite the colossal size of this environment, Attenborough very rightly points out that it is still by no means hugely separated from human life. As well as the famous Pacific Garbage Patch that Elin talked about in another post, there is plastic and other marine waste in the most pristine and remote coral reefs. I have heard stories from fellow divers in the Indo-west Pacific about seeing used nappies floating past on dives. I was lucky enough to be involved with a school trip to Baubau near Sulawesi in Indonesia, and we spent a few hours on an uninhabited island cleaning up trash. On another island in Malaysia I found a DVD player and a washing machine on the beach. These are unusual exceptions – polystyrene, plastic bags and straws are ubiquitous in the ocean anywhere in the world. It’s no different in the UK – the Marine Conservation Society at Southampton spend hundreds of hours removing rubbish from beaches on the South coast. When we see pollution in an area we can all agree it is unpleasant, but as a scientist we understand it in context of this colossal, global and unprecedented problem.

This affects all levels of the marine food web. We tend to think of the deep sea as being this remote alien world, but it is still inextricably linked to human life. Microplastics accumulate in deep sea sediments – at 10,000 times higher concentrations than at the surface. Up to 90% of seabirds have plastic in their guts. Another aspect not explored in the programme is that other pollutants dissolved in water – fouling paint, oil and other contaminants – accumulate on plastics, and so make plastic even more toxic to marine life. Pollution becomes more concentrated in higher levels of the food chain in a process known as ‘biomagnification’, where smaller fish with some pollution in them are eaten in large quantities by larger fish. This means that top predators like tuna, sharks and marine mammals are the most contaminated. And as well as being concerning for environmental reasons, the seafood we eat are no exception – plastic has been found in a third of UK-caught fish, and shellfish lovers may consume up to 11,000 plastic particles per year.

Biodegradable plastic is not biodegradable in the sense one might think. These plastics are held together with degradable fibres, so they break down into smaller components. Eventually, they break down into ‘microplastics’, which then spread into every corner of the ocean. It has been suggested that a layer of plastic will be what will distinguish the human era in the fossil record of the future.

It is extremely heartening to see the reactions to this problem, and some countries (most recently Kenya) have even completely banned plastic bags outright. Hopefully Blue Planet will encourage more people than ever to think twice about whether they need that straw or bag, and eventually encourage governments and large companies to move away from the excessive use of this material.

The post Blue Planet | Episode 4 | Big Blue appeared first on Exploring our Oceans .

It is therefore extremely concerning that reefs are in the worst state they have ever been in. The programme was not exaggerating how serious this is. No reef anywhere on Earth is what it was 20 years ago, and is barely recognisable from 100 years ago. One important consideration in ecological science is setting a baseline – a ‘pristine’ environment, or a ‘fully grown’ fish – to act as a control with which to assess the extent of change. This is usually a nearby area, or the same location a few months or years before. What is problematic is that these baselines change generation to generation (2).

As a young person, the places I have dived and snorkelled that I consider ‘amazing’ would be considered degraded to senior divers who started diving 50 years ago. On a fieldcourse in Bermuda this summer I was struck by the beauty of an offshore reef we visited to measure coral cover – I was surprised to hear the scientists working at BIOS considered this site degraded. The same issue occurs with fisheries, where what is considered a ‘big fish’ by one generation would have been considered a juvenile by a great grandparent. The programme’s spectacular footage from French Polynesia represents the kind of community that most coral reefs would have possessed at one time – today represented by very few extremely remote places. It is thought that before human interference, apex predators like groupers and sharks would have made up the majority of biomass in a reef community (3). Perspective is powerful, and as scientists we must select ours carefully.

Additionally, the corals on which the entire reef ecosystem depends are imperilled worldwide. The largest living structure on Earth, the Great Barrier Reef, bleached two consecutive years in 2016 and 2017 – the first time this has ever happened – in the worst bleaching event in its history. Corals in the Caribbean have declined by 40% in the last five decades (4). Something that I have found as fascinating as shocking considering contemporary life on Earth in the context of its entire history. This decline is a geologically significant event – such large formations dying en mass in a blink of an eye in terms of Earth history is an unusual freak event. The science is increasingly showing that humans are the most influential species of vertebrate in the history of life on Earth.

There have been encouraging suggestions of long-term adaptability – some of the research coming from the Coral Reef Lab at NOC. Some reefs in the Middle East have showed less extreme responses to bleaching. However, I attended a seminar by Dr. Leonard Nurse of University of the West Indies in Barbados a few weeks ago, who is involved in Caribbean coastal management and the Intergovernmental Panel on Climate Change. He made no qualms about mentioning that “no evidence exists that corals can adapt to unabated thermal stress over decadal timescales”.

Change is occurring at both regional and global scales, and although reefs are already declining globally, regional management, intergovernmental climate change agreements and robust science are key to boosting reef longevity and resilience. Seeing the enormous engagement and widespread reaction to the Blue Planet episode is extremely encouraging, and I look forward to seeing a new generation inspired to understand and protect these beautiful habitats.

1. Pascal, N. et al. Economic valuation of coral reef ecosystem service of coastal protection: A pragmatic approach. Ecosyst. Serv. 21, 72–80 (2016).
2. Roberts, C. The Unnatural History of the Sea. (Island Press/Shearwater Books, 2008).
3. Friedlander, A. M. & DeMartini, E. E. Contrasts in density, size, and biomass of reef fishes between the northwestern and the main Hawaiian islands: the effects of fishing down apex predators. Marine Ecology Progress Series 230, 253–264 (2002).
4. Gardner, T. A., Côté, I. M., Gill, J. A., Grant, A. & Watkinson, A. R. Long-Term Region-Wide Declines in Caribbean Corals. Science (80-. ). 301, 958–960 (2003).

The post Blue Planet | Episode 3 | Coral Reefs appeared first on Exploring our Oceans .

Deep-sea hydrothermal vents are one of the seafloor environments now being targeted for mining of their mineral resources, because the “chimneys” that form at vents are particularly rich in metals such as copper that we need for modern technology.

But what are the possible impacts on marine life from mining at deep-sea vents?  For the first of three blog posts to accompany Week 6 of our “Massive Open Online Course” on “Exploring our oceans”, I’ll attempt a summary here, because the impact of greatest concern on marine life is perhaps not the most obvious.  And because it’s perhaps not obvious, this will be long article – starting with some key features of deep-sea vents, and what mining at vents will involve.

What are the key features of deep-sea vents?

Deep-sea vents are undersea hot springs, where mineral-rich fluid gushes out of the ocean floor.  On contact with cold, oxygenated seawater, the minerals in those hot fluids precipitate to build spire-like deposits called “vent chimneys”, and sometimes produce a “black smoke” of suspended particles that rises and disperses above the vents.

Deep-sea vents occur in “vent fields”, each of which is a collection of vent chimneys clustered together in a relatively small area.  Vent fields vary in size: some are just a couple of hundred metres across, while at others the vent chimneys can be spread over several kilometres.

Vent fields are separated from each other on the seafloor by relatively large distances where there is no vent activity.  In some regions, vent fields can be a few kilometres apart from each other, but in other regions it can be several hundred kilometres from one vent field to its nearest neighbour.  So overall, vent fields are rather like “islands”, dotted around the ocean floor, and varying in size and spacing.

The activity of each vent field does not last forever.  Depending on their geological setting, some vent fields may only be active for a few decades, before their fluid flow shuts down, for example if the area is smothered by lava flows from nearby undersea volcanoes, or if the “plumbing” beneath the vent field is disrupted by earthquake activity.  In other regions, however, a vent field can remain active for thousands of years – and go through cycles of activity, switching “on and off” for several millennia at a time.

So this is a key point that we will come back to later: deep-sea vents are not the same the world over.  Some are smaller in area than others, and some are naturally active for thousands of years.

At active vents, microbes thrive by using some of the dissolved minerals in the vent fluids as an energy source, in a process known as “chemosynthesis”.  These microbes in turn provide food for species of deep-sea animals, many of which are only found in such “chemosynthetic” islands of life on the ocean floor.

However, those animal species are never unique to an individual vent field, because if they were, they would go extinct when that vent field shuts down naturally.  The “vent” animals therefore have larval stages in their life cycles that are adapted for dispersal between vent fields, which allow them to avoid extinction despite the ultimately ephemeral nature of the colonies of their adult forms.

Although vent species are not unique to individual vent fields, however, they are specific to particular regions – one species, for example, may be found at vents along 3000 km of mid-ocean ridge, and then either geological or oceanographic barriers may isolate it from other species at vents in neighbouring regions.

So this is another key point that we will come back to later: vent fields are naturally ephemeral, and may be inhabited by species of animals only found at vent fields in a particular region, but never only at one individual vent field.

What is involved in mining at vents?

From plans already made by mining companies, “mineral extraction” will involve machines on the seafloor scraping up and pulverising the “seafloor massive sulfide” (SMS) deposits at a vent field, i.e. the vent chimneys and associated rubble around them.

This material will be pumped to a surface facility, where the metals will be extracted.  The remaining matter will be turned into a slurry, and in some cases may be pumped back down into the depths, to disperse from a pipe in mid-water and eventually settle across a wide area of the seafloor at very low concentration, similar to the fall-out from the natural plume of particles dispersing from the vents themselves.

What marine life will be most affected?

Now let’s think about the marine life that is likely to be most affected by mining at deep-sea vents.  Mining on land has an impact on local wildlife, but on land that wildlife usually occupies habitats much larger than just the area being mined.  So although some garden snails or earthworms may be killed by an excavation on land, that impact doesn’t usually cause concern, because those species are still common in unaffected areas.

So it is important to make a distinction between “normal” deep-sea animals that are found in extensive habitats beyond deep-sea vents, and “vent” animals that are only found in vent environments.

The plume of particle-laden waste water from seafloor mining could have an impact on “normal” deep-sea animals, for example suspension-feeding corals living on rocky seafloor away from the vents, or mid-water animals if the plume clouds the water (remember that many deep-sea animals still use light to communicate, hunt, and evade predators, even at depths beyond on the reach of sunlight).

But those kinds of animals usually have very wide distributions away from vents in the deep sea, so in terms of habitat loss or species extinction they are not particularly at risk from mining at vents; the impacts on them are similar to those on the garden snails and earthworms of our land-mining analogy.  The same applies to animals that may be affected by noise or other disturbance from mining activity, if their species have wide distributions and large populations beyond the impact area.

How will “vent” animals be affected?

But what about the impacts on the “vent” animals, which only live in vent environments?  The animals living on vent chimneys macerated by the mining machines will be killed.  But vent fields are naturally ephemeral features: when a vent field shuts down naturally, all the animals living there die out.  So mining, it is argued, simulates a natural disturbance process at an individual vent field.

In fact, mining does not “switch off” activity at a vent field; instead, it effectively resets the vent field to “time zero” in its natural development, by scraping the seafloor back to bare basalt with hot fluid still gushing out of it.  We know that the larvae of “vent” animals can recolonise that site from other vent fields in the region, because they did so when venting at that site first began (though how variable larval supply is, and whether a community will always follow the same pattern of development, is not yet known for vent fields in many regions).  And the chimneys grow back too (for example, we have seen chimneys grow several metres in a year between visits to some sites).

So on the face of it, mining at vents might seem an attractive proposition (and the word “sustainable” has even been used by some to describe it).  But as is often the case in the natural world, issues arise when we consider cumulative effects across a region, rather than individual sites.

What are the risks to “vent” animals from mining?

In the Western Pacific, where plans for mining at vents are arguably most advanced, most of the vent fields are associated with “back-arc spreading”, rather than being found on mid-ocean ridges.  These “back-arc” vent fields can be extensive, for example stretching over kilometres of seafloor in a ring around the summit of an underwater volcano.

At many of these “back-arc” vent fields, it is possible to mine just one part of the vent field, while creating “set-asides” or “reserves” within the same vent field or area, from which animals can recolonise the mined area afterwards.

That is exactly what mining company Nautilus Minerals proposes to do at the Solwara-1 vent field near Papua New Guinea, and they have worked extensively with scientists in the US to understand patterns of gene flow and thereby define what should be effective reserve areas as sources for recolonisation.

Looking at those plans as an independent observer, I think they will work in terms of mitigating the impact on “vent” animals.  The mined area should recover, with chimneys regrowing and “vent” animals recolonising them.

But – and it is a very big “but” – not all the vent fields on mid-ocean ridges are like the “back-arc” vent field of Solwara-1.  At mid-ocean ridges, would-be seafloor miners are targeting vent fields on “slower-spreading” ridges, such as the Mid-Atlantic Ridge and SW Indian Ridge.  Vent fields on a slower-spreading ridges are often much less extensive in size than “back-arc” vent fields such as Solwara-1, and each vent field on a slower-spreading ridge is typically active for several millennia.

The TAG hydrothermal mound on the Mid-Atlantic Ridge, for example, is one of the largest known mid-ocean ridge sulfide deposits, but its main active mound is only ~200 metres across, unlike the chimneys spread over kilometres at Solwara-1.  And the TAG mound has been active for at least 20 000 years, in cycles of activity and inactivity each lasting 4000 to 5000 years, revealed by “geochronology” of its mineral deposits.

So at the smaller vent fields on mid-ocean ridges, it is not feasible to create “set-aside” or “reserve” areas within a vent field that is being mined: it will be “all-or-nothing” for that particular vent field, considering the footprint required for machinery on the seafloor.  And most importantly: the natural rate of vent-field-wide disturbance on slower-spreading ridges, to which their marine life may be adapted, seems to be once every few millennia.

What we don’t yet know on slower-spreading ridges is how rapidly a colony of “vent” animals develops from “time zero” to become identical to the well-established colonies that we have found so far.  We have not yet found a vent field close to “time zero” on a slower-spreading ridge: the ones we have seen so far have large mineral deposits, indicating that they have been active for some time, and their ecology has remained largely unchanged over the decades that scientists have been visiting them, unlike shorter-lived vent fields elsewhere in the world.  If early stage vent fields on slower-spreading ridges have a different ecology, then mining of several vent fields in a region could reduce the habitat available for species that only inhabit mature colonies.

So this the main impact of concern for “vent” animals: if mining “resets” vent fields in a region at a much higher rate than they “reset” naturally, then we could see overall habitat loss for some “vent” species particular to that region, and ultimately an increased extinction risk for those species as a result of our activities.  So what really matters will be the rate at which we disturb these systems by mining, across a region, compared with their natural rate of disturbance at vent-field scale, and the rate of response of animal colonies to such disturbances on slow-spreading mid-ocean ridges, which we don’t yet know at vent-field scale.

What can be done to reduce the risk of habitat loss and species extinction at vents on slow-spreading mid-ocean ridges?

The most obvious answer to that question is “not to mine those vents”; however, as I will discuss in a further post, the decision has already been made (on behalf of all of us, yet seemingly without us being asked).

If mining goes ahead at active vents on slow-spreading mid-ocean ridges, it is therefore essential that it is carefully controlled at a regional scale, for example identifying a network of vents in a region that must be conserved to ensure viable “metapopulations” of species to recolonise mined sites.  And it will take considerably more research and exploration to inform such an approach in each region.

There is also an alternative at this point: for every “active” vent field on a slow-spreading mid-ocean ridge, there are probably at least ten inactive vent fields, where venting has ceased naturally but where the vent chimneys have not yet been buried by sediments.  As venting has ceased at these sites, the “vent” animals have moved on – but the metal-rich mineral deposits remain.  So potentially, it might be possible to mine inactive vent fields on slow-spreading mid-ocean ridges without the impacts on “vent” animals that we have considered here.

(Recent research shows that marine life at inactive vents can still benefit from chemosynthesis at nearby active vents, but the species involved are “normal” deep-sea animals, typically with wide distributions beyond inactive vents, so they may be similar to the earthworms and snails of our land-mining analogy).

Inactive vent fields may be less attractive to would-be miners, however, because they are harder to find.  We find active vent fields thanks to the plume of mineral-rich fluids gushing out of them, but inactive vent fields lack those tell-tale signals.  But it could still be possible to restrict mining of vents on mid-ocean ridges in international waters to inactive sites.

Whatever the future, effective regulation will be essential for vent mining; and in my next post, we’ll take a look at the organisation that already exists to regulate vent mining in international waters. And then in the final post, we’ll also take a look at some of the investors and contractors involved in developing the world’s first deep-sea vent mine, in the territorial waters of Papua New Guinea.

– Jon Copley (original post March 2014; updated October 2015)

Supplemental, July 2014:

Two further items relevant to this post, in recent weeks:

(1) At the Council of the United National International Seabed Authority (ISA; responsible for administering seafloor mining in international waters) in July 2014, the Netherlands submitted a note recommending that the ISA consider establishing regional environmental impact assessments before awarding any “exploitation” contracts for seafloor mining.  Such a measure, if eventually adopted by the ISA, could address the concerns about “cumulative” impacts of mining at deep-sea vents described here.  So let’s watch this space…

(2) Andrew Thaler and colleagues have recently published an analysis of how connected some populations of animals are between deep-sea vents (which Andrew discusses eloquently in a post here).  Surprisingly, their new study shows that  a “non-vent” animal (Munidopsis squat lobsters, found in lots of deep-sea environments other than just hydrothermal vents) shows greater genetic sub-division than populations of Chorocaris shrimp (which are only known from “chemosynthetic” environments such as deep-sea vents) among deep-sea vents in different areas.  So the assertion in the post above that we should be less concerned about mining impacts on “non-vent” animals, because they can live in areas away from vents, may not actually hold true in all cases…

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