The vertical migration of Antarctic krill may play a smaller role in oceanic carbon storage than previously believed, according to a year-long study in the Southern Ocean. The findings challenge conventional assumptions about the animal’s role in deep ocean carbon sequestration and underscore the need for more nuanced biogeochemical models incorporating ecological complexity. “Antarctic krill play an important role in the biological carbon pump, but without observational data, we risk using inaccurate and misleading assumptions about behaviors that influence carbon export and climate models,” write the authors. The biological carbon pump is a critical oceanic process that transfers carbon from surface waters to the deep ocean, where it can remain sequestered for decades to millennia. This natural mechanism plays a vital role in regulating atmospheric carbon dioxide levels and mitigating global climate change. Antarctic krill (Euphausia superba), a cornerstone species in the Southern Ocean ecosystem, are pivotal contributors to this process through two mechanisms: the sinking of carbon-rich fecal pellets and the active transport of carbon via vertical migrations. With the highest estimated biomass of any wild animal species, krill are believed to export millions of tons of carbon annually to the deep ocean. However, the lack of detailed observational data, especially during polar winters, has led to oversimplified assumptions in biogeochemical models about the extent of krill-driven carbon transport.

To refine these estimates, Abigail Smith and colleagues conducted a year-long study in Prydz Bay, East Antarctica, deploying a seafloor lander equipped with video and high-resolution echosounder systems. By integrating krill density observations – both stationary and migrating – with seasonal chlorophyll concentrations into a numerical model, Smith et al. quantified particulate organic carbon (POC) flux from fecal pellet sinking and active migration. They found that sinking krill fecal pellets contributed 9.68 milligrams of carbon per square meter per day (mg C m⁻² day⁻¹) to the POC flux. However, migrating krill contribute much less, accounting for less than 10% (1.28 mg C m⁻² day⁻¹) of the total carbon flux. According to the authors, no more than 25% of krill undertook daily migrations to depths exceeding 200 meters, with this behavior strongly influenced by seasonal variation. Using these observations, Smith et al. show that traditional models, which often assume a uniform 50% krill migration year-round, result in a more than 200% overestimation of carbon export by krill.

Rising carbon dioxide levels affect more than just the climate; they also affect the chemistry of the oceans. When saltwater absorbs carbon dioxide, it becomes acidic, which alters the aquatic animal ecosystem. But how exactly does ocean acidification impact animals whose genetic makeup can shift depending on environmental cues? A study published in ACS’ Environmental Science & Technology addresses this question through the “eyes” of oysters.

Oxford Net Zero and Carbon Balance researchers reveal the risks of the current UK CCS policy mix and explore how a carbon storage mandate on fossil fuel producers could help the UK meet its climate targets while protecting public finances. 

A UCLA-led team of researchers used the environmental circumstances and fecal samples collected from the six years prior to the severe El Niño drought in Costa Rica to study the relationship between the endocrinologic stress response and survival in white-faced capuchin monkeys.

Monkeys who showed a steeper rise in these stress hormones during the mild droughts were more likely to survive the severe El Niño drought.

As weather intensifies globally, longitudinal studies of how wild animlas cope with changes in temperature, rainfall and food availability can help us understand which species can adapt rapidly.

An understanding of the relationship between severe weather and power outages in our changing climate will be critical for hazard response plans, according to a study published January 22, 2025 in the open-access journal PLOS Climate by Vivian Do of Columbia University, New York and colleagues.