Biodiversity – Cabot Institute for the Environment blog

African penguins could be extinct by 2035 – how to save them

Posted on December 2, 2024December 2, 2024 by amanda.woodman-hardy

African penguin on a beach — African penguin. Photo by Taryn Elliott via Pexels.

In October 2024, the African penguin became the first penguin species in the world to be listed as critically endangered by the International Union for the Conservation of Nature.

This is a sad record for Africa’s only penguin, and means it is now just one step away from extinction.

How did this happen? African penguins (Spheniscus demersus) are found only in Namibia and South Africa. Their numbers have been declining since the 1800s. At that time, they were burnt in ships’ boilers, their eggs were harvested and consumed as a delicacy, and their nests were destroyed by guano-harvesters seeking a rich source of fertiliser.

Such activities are fortunately no longer allowed. African penguins have been protected under South Africa’s Sea Birds and Seals Protection Act since 1973 (and more recently under the Marine Threatened or Protected Species Regulations since 2017).

These laws and regulations ban the capture of penguins or their eggs, and any intentional harm done to them. Fertilisers no longer use guano (penguin excrement). After egg and guano harvesting stopped, the lack of prey (small fish like sardines and anchovies) became the main issue for penguins from the early 2000s.

The impacts of climate change on the distribution and abundance of their food, and competition with industrial fisheries, have contributed to a 70% reduction in this penguin’s population between 2000 and 2024.

We are a group of scientists from universities and non-governmental organisations that have, for years, focused on solutions to save the African penguin. Today, unless the South African government takes urgent steps to protect the African penguin, it will likely become extinct in the wild by 2035. At present there are fewer than 20,000 birds left in the wild.

Penguins are like the canaries in the coal mine. They are disappearing because the ecosystem they rely on, together with many other species, including fish targeted by commercial fisheries, is in dire straits. By saving them, we protect their ecosystem and the other species that rely on it.

Penguins are also valuable to the economy, bringing in revenue from tourism.

What’s worked for the penguin so far

The destruction of African penguins’ nesting habitat over the centuries has been partly repaired by setting up artificial nests in penguin colonies. New research has found that these improve the number of penguin eggs that hatch by 16.5% compared to natural surface or bush nests which remain vulnerable to the elements.

Steps to protect the African penguins’ food supply also worked. One step was the experimental “no-take zones”, where the South African government prohibited fishing around the penguins’ breeding areas between 2008 and 2019.

The government closed commercial fishing of sardines and anchovies in a 20km radius around Robben Island on the west coast and St Croix Island in Algoa Bay for three years. During this time, commercial fishing around the neighbouring penguin colonies of Dassen Island and Bird Island was still permitted. The closure was alternated every three years until 2019 to see if it affected the penguin populations.

The results were positive. Penguins were able to catch fish with less effort and their chicks’ health and survival rates improved. The population increased by about 1% – a small increase, but very important, considering they were already endangered.

In parallel, the African Penguin Biodiversity Management Plan was published in 2013. The plan focused on managing predators, such as Cape fur seals and kelp gulls, and rescuing abandoned eggs and chicks. Thousands of individual penguins were saved and released into the wild over the years.

What has gone wrong for the penguin

Despite these efforts, the African penguin population fell faster from the mid-2010s. This was mostly due to the sudden collapse of the colony at St Croix Island, then the world’s largest African penguin colony.

This collapse coincided with the establishment of ship-to-ship bunkering activities (refuelling ships at sea rather than in ports) in Algoa Bay in 2016. While the ships were refuelling, four oil spills occurred.

Ship-to-ship bunkering also increased underwater noise pollution due to a ten-fold increase of maritime traffic in the bay.

Our previous research has revealed that African penguins are highly sensitive to underwater noise. Noise from ships or drilling equipment chases penguins away from their feeding grounds.

This also uses up the African penguins’ energy, often at a time when they have none to spare. Penguins need energy reserves before starting their annual moult, when they stay ashore for three weeks without eating to replace all their feathers. If they don’t find enough food before or after that stressful period, they die.

Can the African penguin be saved?

The experimental use of no-take zones in penguin breeding areas ended in 2019. A panel of international experts was then appointed by the South African government to review the experiment and suggest a way forward.

The panel said no-take zones should be put in place around all colonies. They recommended ways to balance the benefit to penguins against the cost to fisheries.

But the government departed from the panel’s recommendations and put in place fishing closures aimed at minimising economic losses to fisheries, and not conserving penguins. For example, they closed down fishing in some areas where penguins don’t hunt for fish.

In March 2024, the non-profit organisation BirdLife South Africa and the South African Foundation for the Conservation of Coastal Birds, represented by the Biodiversity Law Centre, asked the Pretoria high court to review and set aside the Minister of Fisheries, Forestry and Environment’s August 2023 decision on fishing closures around key African penguin breeding colonies. The case is still underway.

Meanwhile, bunkering in Algoa Bay has stopped temporarily after the South African Revenue Service detained five ships in September 2023 on allegations of breaching customs laws.

Subsequently, small increases in the St Croix Island penguin population have been seen for the first time in nearly ten years.

African penguins can bounce back when environmental conditions are good. Government and non-governmental organisations have worked hard to prevent various threats to penguins. But critical work remains to be done to protect their foraging habitat (the ocean around their colonies) from polluting activities.

Penguins also need protection from competition with industrial fisheries for fish supplies.

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This blog is by Lorien Pichegru, Adjunct professor, Nelson Mandela University; Alistair McInnes, Research Associate, Nelson Mandela University; Katrin Ludynia, Honorary Research Associate and Research Manager at SANCCOB, University of Cape Town, and Peter Barham, Professor emeritus, University of Bristol. Dr Lauren Waller of the Endangered Wildlife Trust contributed to this article. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Tiny oceanic plankton adapted to warming during the last ice age, but probably won’t survive future climate change – new study

Posted on December 2, 2024 by amanda.woodman-hardy

Global temperature records are expected to exceed the 1.5 °C threshold for the first time this year. This has happened much sooner than predicted. So can life on the planet adapt quickly enough?

In our new research, published today in Nature, we explored the ability of tiny marine organisms called plankton to adapt to global warming. Our conclusion: some plankton are less able to adapt now than they were in the past.

Plankton live in the top few metres of ocean. These algae (phytoplankton) and animals (zooplankton) are transported by ocean currents as they do not actively swim.

Climate change is increasing the frequency of heatwaves in the sea. But predicting the future effects of climate change is difficult because some projections depend on ocean physics and chemistry, while others consider the effects on ecosystems and their services.

Some data suggest that current climate change have already altered the marine plankton dramatically. Models project a shift of plankton towards both poles (where ocean temperatures are cooler), and losses to zooplankton in the tropics but might not predict the patterns we see in data. Satellite data for plankton biomass are still too short term to determine trends through time.

To overcome these problems, we have compared how plankton responded to past environmental change and modelled how they could respond to future climate changes. As the scientist Charles Lyell said, “the past is the key to the present”.

We explored one of the best fossil records from a group of marine plankton with hard shells called Foraminifera. This comprehensive database of current and past distributions, compiled by researchers at the University of Bremen, has been collected by hundreds of scientists from the seafloor across the globe since the 1960s. We compared data from the last ice age, around 21,000 years ago, and modern records to see what happened when the world has previously warmed.

We used computational models, which combine climate trends with traits of marine plankton and their effect on marine plankton, to simulate the oceanic ecosystems from the last ice age to the pre-industrial age. Comparing the model with the data from the fossil record is giving us support that the model simulated the rules determining plankton growth and distribution.

We found that some subtropical and tropical species’ optimum temperature for peak growth and reproduction could deal with seawater warming in the past, supported by both fossil data and model. Colder water species of plankton managed to drift to flourish under more favourable water temperatures.

Our analysis shows that Foraminifera could handle the natural climate change, even without the need to adapt via evolution. But could they deal with the current warming and future changes in ocean conditions, such as temperature?

Future of the food chain

We used this model to predict the future under four different degrees of warming from 1.5 to 4 °C. Unfortunately, this type of plankton’s ability to deal with climate change is much more limited than it was during past warming. Our study highlights the difference between faster human-induced and slower-paced geological warming for marine plankton. Current climate change is too rapid and is reducing food supply due to ocean stratification, both making plankton difficult to adapt to this time.

Phytoplankton produce around 50% of the world’s oxygen. So every second breath we take comes from marine algae, while the rest comes from plants on land. Some plankton eat other plankton. That in turn gets eaten by fish and then marine mammals, so energy transfers further up the food chain. As it photosynthesises, phytoplankton is also a natural carbon fixation machine, storing 45 times more carbon than the atmosphere.

Around the world, many people depend heavily on food from the ocean as their primary protein sources. When climate change threatens marine plankton, this has huge knock-on effects throughout the rest of the marine food web. Plankton-eating marine mammals like whales won’t have enough food to prey on and there’ll be fewer fish to eat for predators (and people). Reducing warming magnitude and slowing down the warming rate are necessary to protect ocean health.

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This blog is written by Rui Ying, Postdoctoral Researcher, Marine Ecology, and Daniela Schmidt, Professor in Palaebiology, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fresh reflection on COP 16 of the Convention on Biological Diversity

Posted on November 11, 2024December 9, 2024 by amanda.woodman-hardy

Margherita Pieraccini and Naomi Millner at COP16. Sat down and holding a block representing the SDGs, — Margherita Pieraccini and Naomi Millner at COP16.

As 2024 is drawing to a close, Conferences of the Parties (COPs) of three major Multilateral Environmental Agreements are happening in close succession: COP 16 of the Convention on Biological Diversity (CBD) was held between end of October and the beginning of November, COP 29 of the UN Convention on Climate Change (UNFCCC) is happening in mid-November, and COP 16 of the UN Convention to Combat Desertification will take place in early December.

Although exploring the synergies between these three COPs is of great importance and their close temporal proximity this year facilitates such discussion, I will focus solely on the CBD COP 16 as I had the opportunity to attend it in person as a University of Bristol academic observer.

CBD COP 16, held in Cali, Colombia started on the 21^st of October and was due to end on the 1^st of November. Negotiations overrun until the morning of the 2^nd of November but they were suspended as the quorum was lost, leaving discussions on some key issues such as the strategy for resource mobilization to be resumed at a later date.

As biodiversity COPs are held biannually, COP 16 was the first COP since the adoption of the Kunming-Montreal Global Biodiversity Framework (GBF) at COP 15 in 2022. No one was expecting the negotiation of another major agreement at COP 16, with the key issue being the implementation of the GBF framework.

An introduction to the GBF

Differently from the Paris Agreement under the UNFCCC, the GBF is not legally binding. Nevertheless, given that the boundary between binding and non-binding instruments in international environmental law is not always so clear-cut, the GBF has a central role in directing biodiversity law and policy. The GBF is a largely aspirational goal and target-oriented instrument. It contains four Goals to ‘live in harmony with nature’ by 2050 and 23 global Targets for 2030, split into three categories, namely ‘reducing threats to biodiversity’, ‘meeting people’s needs through sustainable use and benefit-sharing’ and ‘tools and solutions for implementation and mainstreaming’. The Targets have different degrees of ‘quantifiability’, impacting also on Parties’ strategies and methodologies of implementation.

For example, the well- known ‘30 by 30’ target (Target 3) sets the threshold of 30% of the coverage of protected areas and other effective area-based conservation measures (OECMs) in terrestrial and inland water areas as well as marine and coastal areas to be reached by 2030. In contrast, Target 5, which still falls within the first category of ‘reducing threats to biodiversity’, is framed using a more general language: ‘ensure that the use, harvesting and trade of wild species is sustainable, safe and legal, preventing overexploitation, minimizing impacts on non-target species and ecosystems, and reducing the risk of pathogen spillover, applying the ecosystem approach, while respecting and protecting customary sustainable use by indigenous peoples and local communities.’

There are not only differences between Targets but the wordings of individual Targets themselves is sometimes contradictory, making for complex implementation as conflicting directions are suggested. For example, Target 19 pushes for the marketisation of nature, encouraging the private sector to invest in biodiversity and employing uncritically the language of green bonds and payments for ecosystem services, whilst, at the same, promoting the role of ‘Mother Earth centric action and non-market approaches’. Even if not all targets are rife with internal contradictions, other internal differences may exist, with some objectives expressed in a qualitative rather than a quantitative manner or by reference to concepts that lack unified legal definitions. This makes it more difficult to devise specific indicators, with the consequence that Parties will likely concentrate on the objectives requiring easier interpretative skills. For example, going back to the ‘30 by 30’ Target 3, the quantitative component is followed by references to ‘equitably governed systems’, which could mean very different things to different regulatory actors and there is still much work to be done on the identification of OECMs.

It should be recalled that this is not the first time the CBD employs the language of Targets and Goals. Notably, the CBD Strategic Plan for Biodiversity 2011-2020 included the Aichi Biodiversity Targets structured around 5 strategic goals, though most were not achieved and few partially achieved, as reported in the Global Biodiversity Outlook 5. COP 16’s focus on implementation was therefore crucial to avoid historical failures repeating themselves in 2030.

The spaces and voices of COP 16

COPs are notoriously busy and chaotic events. COP 16 of the CBD did indeed feel busy, with many side events happening simultaneously and in parallel to the formal negotiations of the two Working Groups and plenaries, as well as press conferences and Pavilion events. It was also the largest-ever CBD COP with some 23,000 registered delegates. Yet, the Conference Centre that hosted COP 16 in Cali was very capacious and the horizontal disposition of the spaces facilitated inter-ethnic, inter-generational, inter-disciplinary and of course inter-jurisdictional discussions under a Colombian sky often veiled by clouds.

It was a pleasant surprise to witness the high representation of youth, as well as indigenous peoples and local communities advocating for their rights and the rights of nature, though one may wonder if this was primarily due to the fact that COP 16 was organised in South America where the question of who is indigenous and who is not is not as contested as in other continents (such as Africa) and where youth environmental activism is thriving.

Side events also saw the participation of a plurality of voices, hosting delegates from a myriad of Inter-governmental organisations (IGOs) and Non-Governmental Organisations (NGOs), as well as researchers, Secretariat members and sometimes Parties. Thus, cross-fertilisation of ideas dominated the Conference with the hope that points made in side events by activists, academics, and others could filter through Parties to the negotiation tables. Indeed, many times in side events speakers addressed the audience as if it were an audience entirely made up by Parties’ delegates (seldom the case in practice), encouraging it to report back to the contact groups, which are closed working groups attended by Parties discussing draft texts of decisions.

Human rights as a framing device for different world-makings

The language of human rights pervaded the whole COP 16. This is a recent turn for the CBD, considering that the CBD itself and its instruments pre-GBF do not explicitly refer to human rights. In contrast, the GBF lists among the considerations for the implementation of the Framework a ‘human rights-based approach’. Section C 7(g) states in full that ‘the implementation of the Framework should follow a human rights-based approach, respecting, protecting, promoting and fulfilling human rights. The Framework acknowledges the human right to a clean, healthy and sustainable environment’. There are a few other references to human rights language scattered in the text. For example, in Target 22, reference is made to the ‘full protection of environmental human rights defenders’. The GBF’s explicit inclusion of human rights language and also the acknowledgement of a substantive human right to a clean, healthy and sustainable environment—which cross references the UN General Assembly Resolution of 28 July 2022—has solidified the link between human rights and biodiversity protection. Thus, it is not surprising that delegates at COP 16 used human rights language extensively.

In this context, it was interesting to observe that different groups internalised and strategically deployed human rights language to advance different, sometimes, but not always complementary, world-makings. Youth representatives referred to human rights as a tool for achieving inter-generational equity in biodiversity conservation; many indigenous peoples’ representatives employed human rights language to advance substantive claims such as rights to land and resources as well as procedural ones such as participatory rights in conservation decision-making; women representatives employed human rights language to address gender inequalities in conservation; some UN representatives strongly supported a human rights-based approach to area-based conservation as a means to avoid the tragedies brought about by ‘fortress conservation’; others used human rights language to reiterate key objectives of existing international law instruments.

The concept of human rights returned over and over in COP discussions intersecting with other reflections that unwrap the many lines around which biodiversity is framed and practiced by different communities and actors.

Outcomes and beyond

As mentioned above, COP 16 was suspended leaving for a later date, decisions on some critical issues, such as finance mechanisms and monitoring mechanism to measure Parties’ progress in achieving GBF Targets and Goals. Considering the slow implementation of the GBF- only 44 Parties have submitted revised National Biodiversity Strategies and Action Plans (NBSAPs), which are the main national implementation tools under Article 6 of the CBD- it is disappointing that decisions on budget and monitoring mechanisms have been left pending. However, there were also many achievements at COP 16, including:

the launch of the ‘Cali fund’ to operationalise the sharing of benefits from uses of digital sequence information (DSI);
decisions on Article 8(j), focused on traditional knowledge, innovations and practices of indigenous and local communities, including the adoption of a new Programme of Work on Article 8(j) and the establishment of a new permanent subsidiary body on Article 8(j);
a number of sectoral decisions, including one on the mechanism for identifying ecologically or biologically significant marine areas (EBSAs), which had been the subject of legal and political discussion for eight years.

The decisions related to Article 8(j) stand out considering the central role indigenous peoples and local communities play in the protection of biodiversity and the importance of including different epistemologies in biodiversity decision-making. During COP itself, there were arguments in favour and against the creation of such subsidiary body. Concerns revolved around questions such as ‘Why fixating on only one article of the CBD? Why a subsidiary body on this specific article and not others?’, ‘Would the subsidiary body silo indigenous peoples and local communities concerns?’, ‘Should indigenous peoples and local communities still be clustered together?’ Many counter-arguments were raised promoting the establishment of the subsidiary body as a way to legitimise and render more visible indigenous peoples and local communities’ practices turning these actors as policy makers instead of policy takers included in NBSAPs. The new subsidiary body’s modus operandi will be developed over the next two years, and it will be interesting to follow such development.

Outcomes are important, and in a goal and target-oriented environmental law world such as the one the CBD governance infrastructure presents, it is natural and logical to focus on what is achieved and what is not. However, the success of COP 16, like all COPs, should not solely be determined by its outcomes. It is essential to remember the spaces and the conversations that unfolded in between, the sharing of knowledge by a global community coming together for a few days from very different paths of life and with different agendas, a multitude unified by the shared concern of biodiversity loss, which continues at unprecedented rates and deserves everyone attention in COPs and beyond.

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This blog is written by Cabot Institute for the Environment member, Professor Margherita Pieraccini, Professor of Law at the University of Bristol Law School.

How fly fishing strengthens our connection with wildlife and fosters conservation efforts

Posted on August 21, 2024 by adele.hulin

Whether it’s to reset our mental health or simply to take time out from the hurly-burly of work and urban life, many of us head for oceans and rivers to enjoy their restorative capacities.

Encountering wild animals in these blue spaces contributes to the beneficial effects of being in nature and forms the basis of tourist economies the world over.

Yet, how does our presence affect the creatures that call blue spaces home, and how do encounters with wild species change our relationships with natural environments?

River and stones with green trees and shade — The River Lyd, Devon. Avi Shankar

For nearly a decade, we have been researching human interactions with wild trout and salmon in the context of fly fishing. We spent months immersed in river environments both in the UK (the Lyd and Tamar in Devon, and the Usk and Wye in Wales) and North America (the rivers of the Gaspe region, Quebec and Lewisburg, Pennsylvania). We went fishing, observed and interviewed fly fishers, and learned as much as we could about fish behaviour.

In our recent paper, we explain how human interactions with fish can result in three kinds of interspecies encounters that strengthen people’s connections with wildlife and natural environments.

Separated encounters

Most often, wild animals remain indifferent to humans, driven as they are by natural motivations to feed and breed, within environmental habitats that humans do not fully understand.

For instance, Duane, a novice fly fisher we interviewed in Pennsylvania, didn’t know that trout eat aquatic insects: “I didn’t know squat … flies actually come out of the water?”

This lack of understanding of other species often ensures that wild animals remain undisturbed by human presence. Yet the elusiveness of creatures such as trout and salmon can also motivate people to find out more about them.

Slippery encounters

To improve their chances of catching fish, fly fishers learn about fish behaviour, river environments and the life cycles of the insects that fish feed on.

Equipped with this knowledge, fly fishers become better able to locate trout and salmon, and to select and cast a near weightless imitation “fly” designed to mimic a fish’s insect food.

Learning and honing these skills is a lifelong project during which fly fishers become savvy hunters with heightened abilities to sense what is going on in the water. Equally, fish learn too, becoming shy and ready to slip away from human contact.

Sticky encounters

On the rare occasions that fish are hooked, humans and fish enter what we call a “sticky encounter”. The mixed emotions of catching a wild salmon are captured in Annetta’s field notes:

I look down at this beautiful, majestic being. The fish is a fresh, healthy, silver, bright female … I look at her, she looks back at me … She wrangles free. She’s on a mission to spawn in her home river. I stand up but I’m weak in the knees. Full of pride, humility, and guilt.

Over time, these intense experiences of eye-to-eye contact can inspire fly fishers to consider the welfare of fish.

A wild Usk brown trout in a net — Netted: a wild Usk brown trout – most fly fishers now carefully return their catch back into the river. Avi Shankar

Fly fishers now release the majority of the fish they catch. Moreover, one fly fisher we interviewed explained that he has entirely removed the hooks from his flies, declaring: “I don’t want to catch that fish. I caught so many in my life. I know what the feeling is like.”

Stewarding blue spaces

It may seem ironic that fly fishers become passionate about conserving fish and river environments by practising what many people consider to be a cruel sport. Yet, fly fishers have first-hand experience of declining fish numbers.

Some of our interviewees spoke of trout and salmon as “canaries in the coal mine” – a warning sign of how river ecosystems are threatened by pollution, overdevelopment and climate change. In response, organisations such as the Wild Trout Trust and the Atlantic Salmon Trust highlight the necessity for conservation.

With wild populations of animals declining globally, the presence of humans in blue spaces deserves scrutiny. Nevertheless, interspecies encounters can change the relationship between people, fish and rivers from one of human gratification to one of reciprocity, stewardship and care.

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This blog is written by Professor Avi Shankar, Professor of Consumer Research at the University of Bristol. It is republished from The Conversation under a Creative Commons license. Read the original article.

Avi Shankar standin in the street — Professor Avi Shankar

Indigenous strategies for community engagement to combat climate change in the Amazon

Posted on June 27, 2024 by amanda.woodman-hardy

View of the Tapajós River in the City of Santarém. Credit James Moura.

In the heart of the Amazon Rainforest, a group of young indigenous activists gathered to co-produce strategies for fostering community engagement through audiovisual production to combat climate change. Funded by the Cabot Institute for the Environment and the National Institute of Science and Technology for Amazon Biodiversity Synthesis, the voices of various indigenous peoples found collective strength to develop these strategies in the Lower Tapajós region in the city of Santarém at the Federal University of Western Pará.

This activity took place during the National Seminar of the Tapajós National Forest, which is celebrating its 50th anniversary. The organization of this workshop with young indigenous people began with Kumaruara indigenous leaders who participated in the Amazon Policy Synthesis Project (SynPAm) funded by the Cabot Institute and Policy Bristol at the University of Bristol. This project aimed to identify conservation strategies and gaps in knowledge production related to the Amazon region’s biodiversity. The project involved over 100 stakeholders (researchers, representatives of Non-Governmental Organizations, decision-makers, community leaders, indigenous and quilombola leaders) who engaged in interviews, focus groups, and participatory workshops. One of the suggestions from these various stakeholders was to develop activities where indigenous peoples would also facilitate knowledge production and mobilization processes.

Thus, one of the indigenous activists from the Kumaruara people proposed the development of a participatory workshop to create community engagement strategies through audiovisual production to the Kumaruara Territory Indigenous Council (@povokumaruara). The Indigenous Council collectively deliberated that they could co-facilitate the development of the workshop with the presence of some young indigenous leaders from different territories (see photo below).

Indigenous workshop facilitators. Credit: James Moura.

This activity was the only one co-facilitated by indigenous leaders at the National Seminar. The workshop was conducted collaboratively. The indigenous leaders began with a moment of connection and respect for the sacred spirituality present in the Lower Tapajós territory. With the blessings of the sacred beings, we proceeded to discuss how climate change has been affecting the different territories of the participants. Most of the workshop participants were indigenous people from other ethnic groups, with a small number of non-indigenous participants. A consensus among all present was that climate change is affecting different regions of the Amazon. They commented on how the regions are now drier, hotter, and with fewer fish in the rivers. There is also a greater presence of irregular fires in the region. They pointed out that there is a strong presence of agribusiness, mining, and illegal logging. These factors contribute to the worsening scenario related to climate change.

one of the conversation circle moments during the workshop — One of the conversation circle moments during the workshop. Credit: James Moura.

After this collective sharing moment, it was evaluated how we could produce strategies to promote community engagement to combat climate change. The participants identified that the collective production of audiovisual content could be an important strategy for community mobilization, denouncing human degradation actions in the territories, and raising awareness to fight climate change. The indigenous leaders commented that this struggle is collective. It requires the engagement of both indigenous and non-indigenous people to bring about a transformation in the ways of life of our society. Excessive consumption, waste production, and economic development models were identified as factors promoting global warming. The Kumuaruara indigenous people provided examples of some audiovisual productions they have developed in the territory (see more of these productions here: https://youtu.be/c0atRyk640k?si=Ksnwek1TblnMoPRe; https://youtu.be/i29UR49wwdo?si=3PW5JVKjn_mpf6F9).

Participatory activities took place with the organization of two subgroups, including indigenous and non-indigenous people. They reflected on the need to engage people about the impacts of climate change in the territories. A walk was facilitated on the Campus of the Federal University of Western Pará to identify possible causes and impacts of climate change. Participants reflected on the importance of being attentive to small actions that can increase global warming. They also highlighted the need to understand the impacts of large agribusiness, logging, and mining companies operating in the region. They said that the native forest, along with the rivers, has been destroyed by soybean plantations, cattle raising, illegal logging, and mining activities. Thus, the participants created audiovisual productions demonstrating these relationships, from small personal actions to the significant impacts of the logging, mining, and agribusiness sectors in the region. It is necessary to have a critical and attentive view of the entire production chain to identify whether that specific product being sold in the supermarket is not related to environmental degradation and deforestation in different parts of the world.

video production moment on the UFOPA campus — Video production moment on the UFOPA campus. Credit James Moura

The indigenous peoples of the Amazon, represented by young Kumaruara leaders, call on everyone to combat climate change through daily actions. These actions involve raising awareness of the impacts of climate change on our lives. They highlight the need to compare our contexts over the years and evaluate temperature, vegetation, and climatic events. Furthermore, with this more attentive understanding, we must change habits in a more sustainable and supportive way. Thus, we must understand the production chain of manufactured products and identify if a particular company has been associated with environmental degradation actions. Similarly, we should reduce our need to consume these products and try to consume with less excess. Finally, we must support the actions of indigenous communities worldwide and in the Amazon, which have historically worked on environmental conservation and mitigating climate change.

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This blog is written by Cabot Institute for the Environment members Dr James Moura, Community psychologist, Senior Research Associate of the Synthesis for Policy in Amazonia in the School of Biological Sciences; Dr Filipe França, Lecturer in the School of Biological Sciences; and Dr James Palmer, School of Geographical Sciences, University of Bristol.

Left to right: James Moura, Filipe Franca and James Palmer

How glacier algae are challenging the way we think about evolution

Posted on June 19, 2024 by amanda.woodman-hardy

People often underestimate tiny beings. But microscopic algal cells not only evolved to thrive in one of the most extreme habitats on Earth – glaciers – but are also shaping them.

With a team of scientists from the UK and Canada, we traced the evolution of purple algae back hundreds of millions of years and our findings challenge a key idea about how evolution works. Though small, these algae are having a dramatic effect on the glaciers they live on.

Glaciers are among the planet’s fastest changing ecosystems. During the summer melt season as liquid water forms on glaciers, blooms of purple algae darken the surface of the ice, accelerating the rate of melt. This fascinating adaptation to glaciers requires microscopic algae to control their growth and photosynthesis. This must be balanced with tolerance of extreme ice melt, temperature and light exposure.

Our study, published in New Phytologist, reveals how and when their adaptations to live in these extreme environments first evolved. We sequenced and analysed genome data of the glacier algae Ancylonema nordenskiöldii. Our results show that the purple colour of glacier algae, which acts like a sunscreen, was generated by new genes involved in pigment production.

This pigment, purpurogallin, protects algal cells from damage of ultraviolet (UV) and visible light. It is also linked with tolerance of low temperatures and desiccation, characteristic features of glacial environments. Our genetic analysis suggests that the evolution of this purple pigment was probably vital for several adaptations in glacier algae.

We also identified new genes that helped increase the algae’s tolerance to UV and visible light, important adaptations for living in a bright, exposed environment. Interestingly these were linked to increased light perception as well as improved mechanisms of repair to sun damage. This work reveals how algae are adapted to live on glaciers in the present day.

Next, we wanted to understand when this adaptation evolved in Earth’s deep history.

The evolution of glacier algae

Earth has experienced many fluctuations of colder and warmer climates. Across thousands and sometimes millions of years, global climates have changed slowly between glacial (cold) to interglacial (warm) periods.

One of the most dramatic cold periods was the Cryogenian, dating back to 720-635 million years ago, when Earth was almost entirely covered in snow and ice. So widespread were these glaciations, they are sometimes referred to by scientists as “Snowball Earth”.

Scientists think that these conditions would have been similar to the glaciers and ice sheets we see on Earth today. So we wondered could this period be the force driving the evolution of glacier algae?

After analysing genetic data and fossilised algae, we estimated that glacier algae evolved around 520-455 million years ago. This suggests that the evolution of glacier algae was not linked to the Snowball Earth environments of the Cryogenian.

As the origin of glacier algae is later than the Cryogenian, a more recent glacial period must have been the driver of glacial adaptations in algae. Scientists think there has continuously been glacial environments on Earth up to 60 million years ago.

We did, however, identify that the common ancestor of glacier algae and land plants evolved around the Cryogenian.

In February 2024, our previous analysis demonstrated that this ancient algae was multicellular. The group containing glacier algae lost the ability to create complex multicellular forms, possibly in response to the extreme environmental pressures of the Cryogenian.

Rather than becoming more complex, we have demonstrated that these algae became simple and persevered to the present day. This is an example of evolution by reducing complexity. It also contradicts the well-established “march of progress” hypothesis, the idea that organisms evolve into increasingly complex versions of their ancestors.

Our work showed that this loss of multicellularity was accompanied by a huge loss of genetic diversity. These lost genes were mainly linked to multicellular development. This is a signature of the evolution of their simple morphology from a more complex ancestor.

Over the last 700 million years, these algae have survived by being tiny, insulated from cold and protected from the Sun. These adaptations prepared them for life on glaciers in the present day.

So specialised is this adaptation, that only a handful of algae have evolved to live on glaciers. This is in contrast to the hundreds of algal species living on snow. Despite this, glacier algae have dramatic effects across vast ice fields when liquid water forms on glacier surfaces. In 2016, on the Greenland ice sheet, algal growth led to an additional 4,400–6,000 million tonnes of runoff.

Understanding these algae helps us appreciate their role in shaping fragile ecosystems.

Our study gives insight into the evolutionary journey of glacier algae from the deep past to the present. As we face a changing climate, understanding these microscopic organisms is key to predicting the future of Earth’s icy environments.

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This blog is written by Dr Alexander Bowles, Postdoctoral research associate, University of Bristol

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Wisdom of Generations: Learning from the Hills and Valleys of the Northeast India

Posted on June 4, 2024June 4, 2024 by amanda.woodman-hardy

A tea garden in Dibrugarh, Assam. Image credit: Nborkakoty at English Wikipedia.

Northeast (NE) India is more than just a region on the map; it is a treasure trove of beautiful
natural landscapes and ecological wealth that plays an essential role in our planet’s health. As
we celebrate World Environment Day 2024 with the theme of restoration, let us highlight the
ecological richness of Assam and the other Northeastern states of India. From the slopes of
Arunachal Pradesh to the lowlands of Assam, the NE region is a biodiversity hotspot, home to
unique species found nowhere else on Earth. The more we explore this ecological richness,
the more we discover the wonders and mysteries it holds, sparking our curiosity and interest.

The scenic landscapes of the NE region exemplify a dynamic and harmonious relationship
between humans and nature. Indigenous communities here have cultivated a profound
repository of traditional ecological knowledge passed down through generations. The Bodos,
Mishings, Karbis, Nyishis, Angamis, Khasis, and many others have developed a deep-rooted
understanding of their natural surroundings through intimate interactions with forests, rivers,
and mountains.

One of the most remarkable aspects of this traditional wisdom is the extensive knowledge of
local plants and their uses. These communities have identified and utilized numerous plant
species for food, medicine, shelter, and rituals, demonstrating a profound understanding of
the ecological roles of each species. For instance, the Bodos have long made use of medicinal
plants like Bhut Jolokia (ghost chili) for their therapeutic properties, contributing to the
preservation of traditional healing practices. This knowledge not only highlights the ecological
and cultural diversity of the region but also supports sustainable development and
conservation efforts.

Beyond plant knowledge, these communities have developed sophisticated ecosystem
management practices. Indigenous forest management practices in NE India have
significantly contributed to maintaining biodiversity hotspots and preserving wildlife habitats.
Traditional agroforestry systems, such as jhum cultivation practiced by the Karbi and Khasi
tribes, have shown resilience to climate variability while supporting local livelihoods. According
to a recent United Nations report, indigenous peoples’ territories encompass about 80% of the
world’s remaining biodiversity, underscoring the importance of their stewardship in
conservation efforts.

The wisdom of the hills and valleys also embodies resilience—a capacity to adapt and thrive
amidst changing circumstances. Indigenous communities have overcome challenges like
floods, droughts, and shifting climates by drawing on their deep ecological knowledge.

According to the Indian State Forest Report 2021, Assam’s forest cover is around 35% of its
geographical area, highlighting its critical role in biodiversity conservation and carbon
sequestration. However, this forest cover is declining, and the region faces environmental and
climate challenges, including deforestation, riverbank erosion, and climate change impacts.

Preserving and promoting traditional ecological knowledge is crucial in the face of the global
climate crisis. According to UNESCO, indigenous communities’ traditional knowledge
significantly contributes to the sustainable management of natural resources, benefiting both
local communities and global biodiversity. Recognizing, valuing, and supporting these
practices are essential for environmental conservation, cultural identity, and community
resilience.

Celebrating the wisdom of Assam and Northeast India’s hills and valleys on World
Environment Day reminds us of the transformative power of indigenous knowledge.
Integrating their insights into broader restoration efforts can contribute to building a sustainable
future for all. By embracing the wisdom passed down through generations and augmenting it
with contemporary research and statistics, we, the #GenerationRestoration, can pave the way
toward ecological harmony and resilience in the years to come.

Let us change gears to the tea communities of the NE region. Assam also plays a vital role in
India’s tea production, boasting over 312 210 hectares of tea cultivation. These tea plantations
not only fuel the state’s economy but also hold significant cultural and ecological value. Assam
is among the world’s largest tea-producing regions, with an annual production of 500-700
million kilograms (Mkgs) of tea leaves. The tea industry employs a vast workforce and
supports livelihoods throughout the region, contributing significantly to India’s overall tea
production. The tea plantations in Assam are not only unique but also serve as a prime
example of the harmonious blend of agriculture and biodiversity conservation. The lush green
tea bushes are seamlessly intertwined with shade trees, providing a habitat for various birds
and insects. Assam’s tea is globally renowned for its robust flavor and represents a heritage
deeply rooted in the land and its ecosystems. However, climate and environmental changes
threaten these lush industries, impacting the ecological and socio-economic balance in the
region.

The government has launched several key initiatives to promote development, ecological
conservation, and socio-economic growth across the state. Notable initiatives include the
Assam Budget for Sustainable Development, Assam Tea Tribes Welfare Board, Jal Jeevan
Mission (Har Ghar Jal), Assam Arunodoi Scheme, Assam Green Mission, Assam Skill
Development Mission, and Assam Startup. Effective implementation of these programs aims
to address climate change, promote environmental conservation, and improve the overall
quality of life for the people of Assam. However, the success of these programs depends on
thorough execution at the grassroots level.

What unfolds in the remote corners of Assam reverberates across continents. The lessons
gleaned from this region—on biodiversity conservation, traditional knowledge integration, and
community-led resilience—are universal. They inform global discussions on sustainable
development, emphasizing the need for inclusive approaches that prioritize both people and
the planet.

This World Environment Day, let us heed the call of Northeast India—a call to action for
environmental engagement and climate action involving youth, communities, government
agencies, and non-profit organizations. The region’s youth must understand the challenges
facing their environment and take action to safeguard their communities and natural
surroundings amidst infrastructural growth and development for their own and future
generations. Climate mitigation and adaptation strategies tailored to the region’s unique
context are critical, including afforestation, sustainable agriculture, and flood management
solutions. Youth can lead the way in developing context-specific climate adaptation and
environment restoration strategies that respect local cultures and ecosystems. By immersing
themselves in environmental education, research, and activism, young students can amplify
their voices and influence decision-makers at all levels.

Assam and its neighboring states in India stand out as a distinctive and valuable addition to
the mosaic of Earth’s landscapes. They serve as a beacon of hope and possibility in our
collective journey toward planetary stewardship. The region’s unique natural heritage,
combined with its rich cultural and ethnic diversity, makes it an important site for scientific
research and cultural exchange. As we strive to better understand and protect our planet,
regions like Northeast India offer invaluable insights and opportunities for collaboration.

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This blog is written by Dr Jagannath Biswakarma, School of Earth Sciences, University of Bristol, UK. jagannath.biswakarma@bristol.ac.uk.

‘Foul and loathsome’ or jewels of the natural world? The complicated history of human-frog relations

Posted on February 26, 2024 by amanda.woodman-hardy

When was the last time you saw a frog? Perhaps you came across one in your garden and wondered at its little hands, glossy skin and what looked very much like a contented smile.

Maybe you regularly see them on Instagram or TikTok, where “frog accounts” have proliferated in recent years. People share adorable cartoon frogs, coo over crocheted frogs or go gaga for frogs dressed in cute hats.

In fact, our fascination with frogs isn’t new. As our research has found, the history of human-frog relations is long and complicated – and not all of it is nice.

Why we love frogs

There is a rich history of people really loving frogs.

This is interesting, because many people much prefer mammals and birds over reptiles and amphibians.

But the frog is an exception – for a lot of reasons. People tend to be attracted to baby-like faces. Many species of frog have the large eyes characteristic of young animals, humans included.

Having no teeth and no sharp claws, they also do not seem to be immediately threatening, while many of them have beautiful skin colouring and some are improbably tiny.

Frogs are truly among the jewels of the natural world, unlike toads which – with their more mundane colours and “warty skins” – do not usually inspire the same sense of enchantment.

Their beauty connects us to the wider riches of a vibrant nature hidden from most people’s sight in the dense rainforests of the tropical regions.

And they also connect us to nature in our own backyards. At certain times of the year, they spontaneously appear in our gardens and ponds. They can feel like special visitors from the natural world.

Dissecting human feelings for frogs

Yet relationships between people and frogs haven’t always been so positive. In fact, frogs occupy complicated places across cultures all over the world.

In the Western tradition, the legacy of biblical and classical sources was both negative and longstanding.

References to frogs in the Bible rendered them the instrument of divine anger as a swarming plague.

An etching from the late 1700s shows a plague of frogs.
Wellcome Collection

Frogs challenged early modern zoological taxonomies, moving between classification as serpent, insect or reptile.

Perhaps their resistance to easy placement by humans explains the strong emotional language about them used by Swedish naturalist (and “father of modern taxonomy”) Carl Linnaeus.

When he considered the Amphibia in his 1758 Systema Naturae, he noted:

These foul and loathsome animals are abhorrent because of their cold body, pale colour, cartilaginous skeleton, filthy skin, fierce aspect, calculating eye, offensive smell, harsh voice, squalid habitation, and terrible venom.

In modern science, they sit in a branch of zoology, herpetology, that brings frogs together as “creeping animals” with snakes and lizards.

Frogs have also (or perhaps consequently) suffered in the service of science since at least the eighteenth century because it seemed to be possible to easily replicate experiments across multiple frog specimens.

Frogs were particularly crucial to the study of muscles and nerves. This led to ever more violent encounters between experimenters and frog bodies. Italian scientist Luigi Galvani, for example, did experiments in the late 18th century on legs of frogs to investigate what he thought of as “animal electricity”.

Legs of dissected frogs, and various metallic apparatus used to measure what was thought to be electricity flowing in animals — Scientist Luigi Galvani’s 18th-century diagrams of dissected frog legs and various metallic apparatus he used to measure what was thought to be electricity flowing in animals.
Library of Congress

In this sense, frogs were valued as significant scientific objects, their value lying in their flesh, their nervous systems, rather than in their status as living, feeling beings in the world.

In time, experiments with frogs moved beyond the laboratory into the classroom. In the 1930s, schoolchildren were expected to find frogs and bring them to school for dissection in biology classes.

This practice was, however, somewhat controversial, with opponents expressing sentimental attachment to frogs and concerns that such animal cruelty would lead to barbarism.

Recognising the fragility of frogs

So, our relationship with frogs is complicated. From the frogs of Aesop’s Fables to the meme Pepe the Frog, we have projected our own feelings and frustrations onto frogs, and exploited them for science and education.

Frogs have also borne the brunt of our failures as environmental stewards.

By 1990, the world was seeing a global pattern of decline in frog populations due to destruction and degradation of habitat for agriculture and logging, as well as a global amphibian pandemic caused by the chytrid fungus.

Climate change is also making life hard for many species. In 2022, over 40% of amphibian species (of which frogs and toads are by far the largest group) were threatened with extinction. Their vulnerability has seen the frog – especially the red-eyed tree frog – become a symbol for the environment more generally.

So we should delight in frogs and marvel at how beautiful and special they are while we still can, and consider how we might help save them.

Something to reflect on next time you are lucky enough to spot a frog.

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This blog is written by Susan Broomhall, Director, Gender and Women’s History Research Centre, Australian Catholic University; Andrea Gaynor, Professor of History, The University of Western Australia, and Cabot Institute for the Environment member, Dr Andy Flack, Senior Lecturer in Modern and Environmental History, University of Bristol. This article is republished from The Conversation under a Creative Commons license. Read the original article.

UK peatlands are being destroyed to grow mushrooms, lettuce and houseplants – here’s how to stop it

Posted on February 8, 2024 by amanda.woodman-hardy

Peat is a natural carbon sink but is often found in house plants and other retail products, particularly within the food and farming industry.
New Africa/Shutterstock

During the long, solitary days of lockdown, I found solace in raising houseplants. Suddenly stuck at home, I had more time to perfect the watering routine of a fussy Swiss cheese plant, and lovingly train our devil’s ivy to delicately frame the bookcases.

But I started noticing that these plants, sourced online, often arrived in the post with a passport. Most had travelled from all over Europe, with one common tagline: contains peat.

As a peatland scientist, these labels instantly filled me with horror. Hidden Peat, a new campaign launched by The Wildlife Trusts, is now highlighting the presence of peat in all sorts of consumer products, including house plants.

Peatlands, such as bogs and fens, store more carbon than all of the world’s forests combined. They trap this carbon in the ground for centuries, preventing it from being released into the atmosphere as greenhouse gases that would further warm the climate.

Peatlands have multiple environmental benefits. They are havens for wildlife, providing habitat for wetland birds, insects and reptiles. They supply more than 70% of our drinking water and help protect our homes from flooding.

So why on earth is peat being ripped from these vital ecosystems and stuffed inside plant pots?

From sink to source

Despite their importance, peatlands have been systematically drained, farmed, dug up and sold over the last century. In the UK, only 1% of lowland peat remains in its natural state.

Instead of acting as a carbon sink, it has become one of the largest sources of greenhouse gas emissions in the UK’s land use sector. When waterlogged peat soils are drained, microbes decompose the plant material within it and that results in the release of greenhouse gases such as methane into the air.

Most of the peat excavated, bagged up and sold in the UK is used as a growing medium for plants. Gardeners have become increasingly aware of this problem. Peat-free alternatives have been gaining popularity and major retailers have been phasing out peat-based bagged compost in recent years.

Indeed, the UK government announced they would ban sales of all peat-based compost by 2024. But this legislation has not yet been written and it seems unlikely it will be enacted before the end of the current parliament.

Even if brought in to law, this ban would only stop the sales of peat-based bagged compost of the type you might pick up in the garden centre. Legislation for commercial growers is not expected until 2030 at the earliest. So the continued decimation of the UK’s peatlands could remain hidden in supply chains long after we stop spreading peat on our gardens.

Hide and seek peat

For consumers, it’s almost impossible to identify products that contain peat or use peat in their production. All large-scale commercial mushroom farming involves peat and it is used for growing most leafy salads. It gives that characteristic peaty aroma to whisky, and, as I found out, is a popular growing medium for potted plants.

But you’d struggle to find a peat-free lettuce in the supermarket. The Hidden Peat campaign asks consumers to call for clear labelling that would enable shoppers to more easily identify peat-containing products. Shoppers are also encouraged to demand transparency from retailers on their commitment to removing peat from their supply chains.

You can ask your local supermarket about how they plan to phase out peat from their produce. Some supermarkets are actively investing in new technologies for peat-free mushroom farming.

Make informed purchases by checking the labels on garden centre potted plants or source plants from peat-free nurseries. The Royal Horticultural Society lists more than 70 UK nurseries dedicated to peat-free growing.

You can write to your MP to support a ban on peat extraction and, crucially, the sale of peat and peat-containing products in the UK. That ensures that peat wouldn’t just get imported from other European countries.

Pilots and progress

The UK government recently announced £3.1m funding for pilot projects to rewet and preserve lowland peat, with peat restoration seen as a cornerstone of net zero ambitions. This campaign calls for further acceleration of peatland restoration across the UK.

As a research of the science behind peatland restoration, I see firsthand the enormous effort involved in this: the installation of dams to block old agricultural drainage ditches, the delicate management of water levels and painstaking monitoring of the peat wetness.

I spend a lot of time taking samples, monitoring the progress, feeding results back to the land managers. Like many other conservationists, I work hard to find ways to preserve these critical habitats.

But sometimes, there may be a digger in the adjacent field doing more damage in a day than we could undo in a lifetime. That’s the reality, and the insanity, of the UK’s current peatland policies.

We heavily invest in restoring peatlands, yet fail to ban its extraction – the one action that would have the most dramatic impact. By demanding that peat is not only eradicated from garden compost, but weeded out of our supply chains, we can keep peat in the ground, not in pots.

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This blog is written by Cabot Institute for the Environment member, Dr Casey Bryce, Senior Lecturer, School of Earth Sciences, University of Bristol.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Casey Bryce

The clam before the storm

Posted on December 8, 2023 by amanda.woodman-hardy

Cornish mussels

How can you not love a bivalve? I certainly spent seaside holidays picking long, thin razor shells out of the sand on the beach, marvelling at their sharp edges and brown and cream patterned growth lines. I still love clambering over rocky shorelines thick with the blue-black ovals of mussels, encrusted with limpets and rough barnacles, layered with salty strands of seaweed.

Bivalves are a keystone part of a rich ocean fauna, interlocked with the ecology of the marine environment and intertwined with lives of both ancestral and modern humans. Seafood, and particularly shellfish such as mussels, oysters, cockles, scallops and clams have long been part of the human diet. The European market for mussels alone topped 600,000 kg last year (FAO.org), the majority of which are consumed in France, Spain and Italy. Just take a moment to imagine the delicious fragrance of a seafood paella, and you will appreciate why they are so popular. Unfortunately, the future of shellfish is becoming more uncertain as the climate heats up. The days when oysters are used to fire the passions of young lovers, or indeed for lovers to gift each other nacre jewellery or pearls, may be coming to an end. Climate change is likely to lead to a scarcity of oysters and an inability for them to thrive, meaning much smaller individuals, which will make such tokens harder to obtain, more expensive or simply not available anymore.

Aside from being a food source, bivalves are an essential part of the ecosystem in both marine and freshwater habitats. One important task that bivalves do is to filter the water, collecting particles of microalgae, phytoplankton, bacteria and silt. The indigestible particles are packaged with mucus and excreted as a sandy deposit that sinks to the sea floor. In this way, bivalves help to clean murky, turbid water. Some bivalves do this at an incredible rate; green mussels (Perna analiculus) or sea scallops (Placopecten magellanicus) can filter in excess of 10 gallons of water every day. Removing and digesting the algae reduces the number of algal blooms that occur, and sticking sediment particles together so they sink, clears the water. This allows light to penetrate deeper into the ocean, benefitting photosynthetic organisms attached to the seabed.

The structure of the seabed is altered by the presence of bivalves. Some bivalves, such as Venus clams (Veneridae) bury themselves in soft sediments, helping to stabilise the sand. Others attach themselves to rocks using strong root-like threads. Reefs are reinforced by encrusting bivalves, which help to reduce shoreline erosion. This feature is becoming more important as the frequency and intensity of severe weather events is set to increase.

The shells of bivalves are made from either calcite or aragonite, which are different forms of calcium carbonate. The two forms are found in different species and at different stages of the life cycle. They have slightly different chemical properties but they both contain carbon in the form of carbonate, which molluscs extract from seawater. When the shellfish die, the shells drift to the ocean floor to begin the transition into rock such as limestones, ultimately locking carbon away and becoming an important carbon sink. Increasing carbon dioxide in the atmosphere means more carbon dioxide is dissolving in the oceans. Although this might seem like a bonus for the shell-building fauna, the carbon dioxide forms a weak solution of carbonic acid, and this is altering the pH of seawater. Acid reacts with carbonate, dissolving it, so that shelly sea creatures have to work harder to build and maintain their shells.

The complexity of reefs and other underwater habitats is enhanced by bivalves, not just with structural strength, but with complex architecture, which provides niches, refuges and points of attachment for other species. Plenty of creatures apart from humans enjoy munching on bivalves. Squid and octopods can prise the hinged shells apart using the suckers on their tentacles to get at the tasty meat inside. Bivalves also contribute to the food web by spawning large volumes of eggs and larvae. These drift on the ocean currents, providing an essential food source for pelagic fish and other hunters, such as baleen whales.

Having convinced you that bivalves are amazing, what does the future hold for hinged molluscs? Many studies have looked at how different conditions affect bivalves, with some coming to positive, and some to negative conclusions. Cherry picking the answer you want does not necessarily reflect the overall trend and can be quite misleading. One way that scientists use to get an overview of multiple studies is to carry out a meta-analysis. This is a way of combining all the studies to give a statistical probability to each value being tested.

We gathered data on how well bivalves grow under different conditions predicted to change by climate change models. Growth rate can be altered by temperature, pH, oxygen availability and salinity. Ocean temperature is increasing, and this will affect the metabolism of cold-blooded organisms, who rely on the external environment for internal temperature regulation. The pH of the oceans is becoming more acidic, causing the thinning of shells in some shelled sea creatures.

Areas of the ocean are becoming periodically, or permanently short of oxygen. This is happening in two ways. There are widespread dead zones spreading out from the estuaries of major rivers (e.g the Ganges or Mississippi) where nitrates and other pollutants are causing eutrophication, which uses up all the dissolved oxygen. Across water courses as a whole, less oxygen is present in water at higher temperatures because oxygen doesn’t dissolve as well in warm as opposed to cold water. Recent summer heat-waves have left a raft of dead, floating, aquatic organisms, both in marine settings and in inland lakes and rivers. Last summer I caught the fire-brigade pumping air into a local fishing pond, trying, mostly unsuccessfully, to prevent the fish from suffocating.

The last climate stressor that we included in our meta-analysis was salinity. As the planet warms, leading to the melting of ice-caps and glaciers, the sea level will rise with the influx of fresh water. This will alter the salinity, especially in the areas of melt-water run-off around coasts where most species of bivalves tend to live. We wanted to see if salinity changes would be problematic for bivalves, and how that would interact with the other climatic changes. One of the interesting things about meta-analyses is that the effect not only of individual stressors can be evaluated, but also the effect of the interaction of stressors. Do they combine to become more than the sum of their parts, or do they counteract each other to have an overall negligible effect?

What we found was that each of the environmental stressors individually reduced bivalve growth, but that combinations of stressors – such as a temperature increase coupled with an increase in acidity – acted together to reduce growth in a more pronounced way. If climate changes in the way that most models are predicting, then they are also predicting fewer, smaller bivalves that take longer to mature. This may disproportionally affect low-income, island nations, such as the Maldives, where a large proportion of the diet is sourced directly from the sea. For the fishing industry, this means sustainable harvesting limits will need to be adjusted over time to allow time for bivalves to grow to maturity.

This is particularly pertinent because the types of bivalves that have been studied are nearly all either commercial or easy-to-collect reef-building species. They come predominately from the northern hemisphere, and there is a distinct lack of studies on African and tropical species. There are over 100 families of bivalves, of which just 18 have had quantitative growth studies carried out. In the studies we used, 81% of them were on just four families: oysters (Ostreidae), mussels (Mytilidae), scallops (Pectinidae) and Venus clams (Veneridae). There are an awful lot of families we know nothing about, and it isn’t necessarily true that how one species responds informs us accurately about what another species might do. Temperature, for example, really slows down the growth of oysters, scallops and mussels, but can increase the growth of Venus clams and pen shells (Pinnidae). I can see you throwing your hands in the air and asking “Why??”

In this case, the answer seems to lie in the habitat or mode of life that the bivalve inhabits. The families that grow faster in warm waters are the type that bury themselves deep in the soft sand or mud of the seabed. This seems to act as a protective buffer against temperature changes, whereas bivalves attached to the surface are exposed to temperature extremes and so they show reduced growth.

The data became even more interesting when we looked at how different life stages responded to environmental stressors. Nearly all (84%) of the studies we could include in our meta-analysis had been carried out on eggs/larvae or juveniles. This of course, makes perfect sense if you are studying growth, as young organisms do an awful lot more growing than adults. It does, however, leave a hole in the data, and that can lead to biased conclusions.

Very young bivalves, which are generally a free-living part of marine plankton, grow less well in warm, acidic or low oxygen conditions. Low salinity doesn’t seem to be an issue. Adults, on the other hand, can tolerate warm, acidic or low oxygen conditions singly, but struggle when these occur in combination. Adults are also strongly affected by low salinity (in the very few studies that have tested this). Again, this makes reasonable sense. Adults are fixed to whichever rock they settled on, and so survival depends far more on metabolic tolerance to environmental extremes. Mobile, free-swimming larval forms have a greater ability to move away from uncomfortable conditions, searching for somewhere they can flourish.

However, larval vulnerability indicates that in the future bivalve populations (as opposed to individuals) will grow more slowly and may suffer from recruitment and settlement problems. It may be difficult, slow or impossible for bivalve colonies to regenerate after disturbance or harvesting, leading to major population crashes.

Climate change is going to pose some challenges to the populations of bivalves. Bivalves supply the seafood industry, filter our water, stabilise our shorelines and produce planktonic larvae, which bolsters the ocean food web. Minimising the effects of climate change will help to protect this keystone fauna and enable them to continue to form such an essential part of the natural world. I hope my children’s children can still delight in finding ropes of mussels and living pearls.

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This blog is written by Rachel Kruft Welton. With thanks to George Hoppit for proof-reading and suggestions. Read more about their research.

Rachel Kruft Welton