11/15/2025: Orcas hunt great white sharks, golden mussels are overrunning the California Delta, more action needed for climate change, Louisiana communities lead pollution monitoring, and more…
Welcome to the fourth weekly compilation of noteworthy biodiversity and sustainability news! And apologies for the delay – it’s been a busy week, so this edition is a little late. I’ll be back on my normal schedule next week
Lots of news happened again this week – scroll down to read about:
- Biodiversity: Killer whales hunt great white sharks for their livers; nature preserves may not provide all the biodiversity benefits that are needed; golden mussels are overrunning the California Delta; thousands of mammal species are added in newest update.
- Climate Change: COP30 participants demand less talking and more doing; Exxon funded right-wing thinktanks to spread climate misinformation.
- Agriculture: Retired farm fields are found to be carbon sinks, not sources.
- Pollution: citizen-led pollution monitoring in Louisiana; earthworms can counteract some of the negative effects of microplastics on soils; a primer on hormone-disrupting chemicals.
I hope you enjoy the articles. If any particularly resonate with you, please leave a comment or share other recent stories you think others would find interesting!
Biodiversity
Alexa Robles-Gil reports for the New York Times on a recent study that found killer whales, also known as orcas, attacking young great white sharks off Baja California in Mexico. The orcas used specific techniques to hunt the sharks, flipping them upside down and extricating their livers, leaving the rest of the body behind.
Livers are particularly nutrient-dense. As Robles-Gil writes:
“It’s the only thing that’s really worth it for their time,” said Taylor Chapple, a marine ecologist at Oregon State University who was not involved with the research. “It’s sort of like they’re going for the cheeseburger surrounded by a bunch of celery.”
Similar behavior has been observed with South African orcas, but there they targeted adult white sharks that have larger livers. The South African orcas used slightly different techniques to kill the sharks, so researchers believe that orcas learn the specific hunting method from other members of their group.
Protecting biodiversity is complicated, and saving individual species without also preserving where they live, or other species with which they interact, is rarely successful in the long term.
A recent study documented that nature preserves may not be as effective at preserving well-functioning ecological systems as expected. As Miguel Lurgi, one of the study authors, reports in the Conversation:
“What works for conserving species does not necessarily work for conserving the ecological interactions between them. Preserving these relationships is crucial because they underpin ecosystem stability.
If predators decline or disappear altogether, their prey can grow, unchecked. This may disrupt the balance of an entire ecosystem. One striking
example comes from the Aleutian Islands off Alaska, where the loss of sea otters led to an explosion in sea urchins and the near collapse of kelp forests.
(If you’d like to learn more about how sea otters affect kelp forests, check out my recent post about them on Substack!)
Our study found that how well a protected area works depends a lot on where it is located and how it is managed. We found that factors such as remoteness, habitat diversity, human pressure and the amount of surrounding agricultural land were all linked to how well food webs were preserved.
Our understanding of biodiversity keeps growing – a recent study by several universities just updated the number of known mammal species, cataloging a nearly 25% increase from the previous update 20 years ago. As Gabriela Harrod from Arizona State University reports, the Mammal Diversity Database now recognizes 6,759 living and recently extinct species of mammals. She quotes Nathan Upham, assistant professor at ASU and one of the co-authors:
“Rodents and bats together make up almost two-thirds of mammal diversity,” Upham said, about 41% rodents and 22% bats. “They’re everywhere, but they’re also some of the least understood animals, partly because they’re small, nocturnal and elusive. There’s still an incredible amount left to discover about small mammals.”
Rodents – mice, rats, squirrels, beavers, hamsters and others – and bats had some of the largest increases in numbers, as did primates and the group that includes shrews and moles.
“It’s easy to think we’ve already found everything,” [Upham] said. “But we’re still learning about the animals that share this planet with us. Every new name is a reminder that the story of life on Earth is still being written, and that we’re just beginning to understand how much there really is.”
An invasion of golden mussels is threatening California’s Sacramento-San Joaquin Delta, Rachel Becker reports for CalMatters. The mussels were first discovered a year ago but are already doing considerable damage, threatening water supplies for cities and farms by coating pipelines, boats and piers in thick layers. As Becker writes,
The consequences could be devastating for farming, said Christopher Neudeck, president of the civil engineering firm Kjeldsen, Sinnock & Neudeck and a district engineer for many of the Delta islands. The region produces dozens of different crops, and drives more than $4.6 billion in agricultural output.
“If (the siphons) plug up, we’re going to lose billions of dollars worth of agricultural production,” Neudeck said. “We know it’s become extremely problematic. But nothing has really been done. We’re just in a holding pattern, waiting to let the second shoe drop.”
State and federal funding is slow to arrive, and although California lawmakers allocated $20 million to fight invasive mussels, the Department of Fish and Wildlife reports that no funds are set aside to combat golden mussels in the Delta.
Climate Change
We’re in the middle of COP30, the United Nations Climate Conference in Belém, Brazil. Seth Borenstein and Mauricio Savarese with the Associated Press report:
For 30 years, world leaders and diplomats have gathered at United Nations negotiating sessions to try to curb climate change, but Earth’s temperature continues to rise and extreme weather worsens.
So this month, they’re hoping for fewer promises and more action.
Past pledges from nearly 200 nations have fallen far short and new plans submitted this year barely speed up pollution-fighting efforts, experts say.
The U.S. is mostly skipping the summit, and President Donald Trump has begun the process of withdrawing from the Paris Agreement, which aims to keep the increase of the global average temperature to less than 1.5 degrees Celsius (2.7 Degrees Fahrenheit) by the end of the century.
Geoff Dembicki reports for the Guardian about a trove of previously unpublished documents between Exxon and a group of rightwing thinktanks that revealed efforts to spread climate denial and undermine the U.N. climate treaty process.
As Dembicki writes:
The documents, which include copies of the actual cheques Exxon sent, consist of internal documents and years of correspondence between the Texas-based fossil fuel company and Atlas Network, a US-based coalition of more than 500 free-market thinktanks and other partners worldwide.
The money Exxon sent to Atlas Network helped finance Spanish and Chinese translations of English books denying that human-caused climate change is real; flights to Latin American cities for American climate deniers; and public events that allowed those deniers to reach local media and network with politicians.
Agriculture
At the intersection of climate change and agriculture, Emma Bryce reports in Anthropocene Magazine about the surprising discovery that retired farmlands are a carbon sink, not a carbon source:
When farmland is returned to the wild, it shows a striking ability to hold onto the carbon that built up in farm soils over time, retaining this stock for 30 years or more, a unique, long-term study shows.
The new finding challenges a long-held view that farmlands release large amounts of CO2 when they are rewilded.
The study was done on retired farmland in Minnesota with sandy soils, so it’s possible that results on other types of farmland could be different. But the finding turns prior understanding about how carbon is stored in fallow farm fields and the feasibility of recultivating abandoned farm fields on its head.
Pollution
Elise Plunk reports in the Louisiana Illuminator about efforts by non-scientists to collect data on air and water pollution from nearby industries. Scientists, in turn, use the data to understand what impact local pollution levels can have on air quality, fisheries or their health.
Fishermen and advocates alike suspect air quality and fisheries problems in Cameron have ties to the nearby LNG facilities but have no independent data to back up their suspicions. The environmental groups received grants to buy monitoring equipment and hire fishermen to collect data and partner with scientists for research projects.
Data collected by non-scientists has not always been accepted by the scientific community because of concerns over the lack of training, but that is beginning to change.
“There’s been increasing recognition of the power of these types of projects to collect really useful data,” said Bradley Allf, a postdoctoral research associate at Colorado State University who uses participatory science to study urban ecology and conservation.
Other hurdles to use the data exist, however – last year the Louisiana Legislature enacted strict quality standards for data used for enforcement. Environmental groups say are the standards are too strict, require costly equipment and prevent citizen science projects.
Microplastics can contaminate soils and have been shown to degrade soil quality and hinder nutrient absorption by plants. Newswise reports on a recent study that found earthworms can alleviate some of the adverse effects, increasing soil nutrient and organic matter content and resulting in increased plant growth.
Hailong Wang, part of the Chinese research team, said in a statement:
“We hope that the results of this study can be applied in future ecological restoration efforts and provide a scientific basis and solutions for mitigating the adverse effects of microplastic pollution on plant growth.”
Chemicals that disrupt our body’s hormones are everywhere, from PFAS (aka “forever chemicals”) in many consumer and industrial products, phthalates that are used as plasticizers and are found in everyday products such as shampoo and food packaging, to BPA (aka Bisphenol A) that is used in plastics and the lining of some canned foods and beverages.
Winnie Roberts and Kathy Talkington with the Pew Charitable Trusts compiled a primer of five facts to know about these chemicals – often referred to as “endocrine-disrupting chemicals” (EDC). So if you’re confused about the different chemicals, this is a good place to start.
As Roberts and Talkington write, scientists estimate that 1,000 or more chemicals are likely hormone disruptors, and most U.S. residents are affected:
Virtually all Americans have more than one type of EDC in their blood. For example, data from the Centers for Disease Control and Prevention’s biomonitoring programs shows that 97% have PFAS and 98% have phthalates in their systems. Many of these chemicals have been associated with serious health conditions, such as diabetes, breast cancer, infertility, and high blood pressure.
The good news is that it’s possible to reduce our exposure to these chemicals if we stop their use. We have done that with several older chemicals that are no longer produced and whose levels in blood are now decreasing. But it often takes legislative action to limit the production and use of potentially harmful chemicals.
That’s it for this week. I hope you found the articles interesting, drop a note in the comments if you’d like to see more on a particular topic in the future!
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