Food webs

In late spring, estuaries along the U.S. Gulf Coast come alive with newborn fish and other sea life. While some species have struggled to adjust to the region’s rising water temperatures in recent years, one is thriving: juvenile bull sharks. We study this iconic shark species, named for its stout body and matching disposition, along the Gulf of Mexico. Over the past two decades, we have documented a fivefold increase in baby bull sharks in Mobile Bay, Alabama, and a similar rise in several Texas estuaries, as our new study shows. Despite the bull shark’s fearsome reputation, baby bull sharks are not cause for concern for humans in these waters. While adult bull sharks are responsible for an occasional unprovoked attack, baby bull sharks haven’t fully developed the skills needed to hunt larger prey. And you’re still far more likely to be killed by bees, wasps or snakes than sharks. The fascinating life of a young bull shark Most sharks are fully marin...

Winters on the Great Lakes are harsh – so much so that the scientists who work there often focus on the summer months, when tiny microbes at the base of the food chain were thought to be most productive. However, emerging research is changing our understanding of these winter ecosystems and shining a light on a vibrant world of winter activity just below the ice. Scientists discovered in the early 2000s that communities of diatoms – tiny photosynthesizing algae – were thriving in the light under the wind-swept lake ice. But, it turns out, that was only part of the story. As the Great Lakes’ winter ice disappears – it hit record lows in the winter of 2023-24 – new analyses show that some diatoms appear to have a different way to create energy and survive in the dark, turbid ice-free water until summer. A thin slice of Lake Erie ice collected by a scientist has diatom algae growing on the bottom....

They go by many names – pigs, hogs, swine, razorbacks – but whatever you call them, wild pigs (Sus scrofa) are one of the most damaging invasive species in North America. They cause millions of dollars in crop damage yearly and harbor dozens of pathogens that threaten humans and pets, as well as meat production systems. Although wild pigs have been present in North America for centuries, their populations have rapidly expanded over the past several decades. Recent studies estimate that since the 1980s the wild pig population in the United States has nearly tripled and expanded from 18 to 35 states. More recently, they have spread rapidly across Canada, and these populations are threatening to invade the U.S. from the north. The wild pigs in Canada are unique because they were originally crossbred by humans to be larger and more cold-hardy than their feral cousins to the south. This suite of traits has earned them the name “super pigs” for good reason. Adu...

At the United Nations biodiversity conference that opens in Montreal on Dec. 7, 2022, nations aim to create a new global framework for transforming humanity’s relationship with nature. The conference logo features a human reaching to embrace a panda – but from an ecological perspective, a weasel or badger would be a more appropriate choice. Logo for the COP 15 conference in Montreal, which was delayed from its original 2020 date due to COVID-19. Convention on Biological Diversity, CC BY-ND Large mammals with widespread appeal, also known as charismatic megafauna, often represent the highest achievement in biodiversity protection. As the logic goes, saving the tiger, polar bear, wolf or lion means saving an entire ecosystem, since these species often have large ranges and may sit at the top of food chains. But research shows that, relatively speaking, many large charismatic species aren...