The Plant Press

Delayed ocean acidification confirmed in Gulf of Maine

From Plant Press, Vol. 28, No. 2, April 2025.

-Adapted from The Pinnacle Gazette

Recent research indicates a delayed onset of ocean acidification in the Gulf of Maine due to complex water mass interactions and temperature variations. The Gulf of Maine, significant for its ecological and economic value, particularly for fisheries, has become the focus of increasing scrutiny due to concerns about rising atmospheric CO₂ levels affecting marine life.

The study reveals a surprising trend: seawater pH levels were low (~7.9) for much of the last century but increased by +0.2 pH units over the past 40 years, contradicting the rising levels of atmospheric CO₂. This unexpected increase raises questions about the factors influencing coastal water chemistry and the potential impacts on marine species.

Location of crustose coralline algae samples in the Scientific Reports study and modern hydrographic context of the Gulf of Maine. Sea surface temperature (A), pH (B), and calcite saturation state data (C). Ω calculated from bottle measurements of alkalinity and dissolved inorganic carbon. Detailed sample locations of the Clathromorphum compactum coralline algae specimens used in this study are shown in panel (D). (image from Scientific Reports, https://doi.org/10.1038/s41598-024-84537-3)

Conducted by researchers including J.A. Stewart (University of Bristol), Walter Adey (Smithsonian’s National Museum of Natural History), and others, the study spans pH records from 1920 to 2018 CE, primarily focusing on changes noted from 1980 to 2000 CE. The researchers employed boron isotope measurements from long-lived coralline algae to create proxy records indicating seawater pH trends.

Nearly half of the species of Heliconia are threatened with extinction

From Plant Press, Vol. 28, No. 2, April 2025.

A new analysis from researchers at the Smithsonian’s National Museum of Natural History reveals that nearly half of the genus Heliconia, a group of tropical plants popular for their bright, beakshaped flowers, are threatened with extinction. The findings, published in the journal Plants, People, Planet (https://doi.org/10.1002/ppp3.70000), reveal that many of these imperiled plants are not found within protected areas or botanical gardens, making additional conservation action crucial to saving these charismatic, horticulturally important and ecologically significant floras.

Heliconia sclerotricha in Ecuador. Heliconia plants are famed for their flowers, which come in a variety of vivid hues, including intense yellows, fiery oranges and rosy reds. (photo by W.J. Kress)

The new work places Heliconia among a select group of plants to undergo a detailed, comprehensive conservation assessment. Traditionally such an effort requires countless hours of demanding fieldwork. Instead, the new project relied on previous field work conducted by research botanists like W. John Kress, an emeritus curator at the museum and one of the authors of the new study, who spent decades collecting Heliconia plants in the tropics. These efforts yielded thousands of dried specimens and data-rich labels that are housed in herbaria around the world, including the museum’s United States National Herbarium.

“The data that is stored in the herbarium is a scientific treasure that makes a project like this feasible,” said conservation biologist Gary Krupnick, who heads the museum’s Plant Conservation Unit and is one of Kress’ coauthors on the new study. “We built upon the valuable time and resources that past researchers have spent going out into the field and counting plant populations.”

The genus Heliconia contains 187 species of tropical plants related to bananas. While a handful of Heliconia species are native to western Pacific islands, the majority live in rainforests throughout tropical Central and South America. Here, the plants are important ecological resources for a variety of creatures, including bats in the Pacific tropics and hummingbirds in the New World tropics, which are the primary pollinators for many Heliconia species. The plants produce nectar to entice the flying animals, who then spread pollen to other flowers as they flutter about.

Heliconias planted as ornamentals in a garden in Panama. Gardeners have cultivated Heliconia species for centuries as striking ornamental plants. This popularity has put some species at risk of overexploitation and poaching. In addition, Heliconia plants are threatened by habitat loss and fragmentation, invasive species and climate change. (photo by W.J. Kress)

Heliconia plants are famed for their flowers, which come in a variety of vivid hues, including intense yellows, fiery oranges and rosy reds. Their reproductive structures are composed of waxy, elongated leaves called bracts. Many Heliconia flowers resemble the striking plumage of birds-of-paradise. Others evoke lobster claws or toucan beaks.

Gardeners have cultivated Heliconia species for centuries as striking ornamental plants. This popularity has put some species at risk of overexploitation and poaching. In addition, Heliconia plants are threatened by habitat loss and fragmentation, invasive species, and climate change.

Art by Alice Tangerini: Schiedea waiahuluensis W.L.Wagner, Weller, B.Nyberg, & A.K.Sakai

From Plant Press, Vol. 28, No. 1, January 2025.

Schiedea waiahuluensis, a newly discovered species from Hawai‘i, is likely the first plant to be identified and collected using drone technology. The species is found only on the dry cliffs of Waiahulu on the island of Kauaʻi, with an estimated population of around 345 individuals, primarily growing on bare rock surfaces in small pockets of soil. Seeds from the first drone-collected samples were sent to the greenhouses of the University of California Irvine, where nursery-grown plants allowed for detailed measurements and material for the official type specimen. Alice Tangerini used the Holotype cuttings sent from UC Irvine for the inked illustration of the habit and inflorescence. Digital images taken from the cuttings and UC Irvine photos were used for the flower details to show the diversity of the flower types and were drawn digitally in Adobe Photoshop.

Staff Activities

From Plant Press, Vol. 28, No. 1, January 2025.

On November 25, Erika Gardner gave a presentation titled, “What is a Type Specimen,” to the Riderwood Senior Living Community Garden Club in Silver Spring, Maryland. The presentation included historical collecting accounts and the continued preservation of specimens, the use of DNA analysis of herbarium specimens to uncover new species to solve cryptic speciation issues, and how botanical illustrators use their skills to highlight characteristics of a plant to distinguish it from other similar species. 

Staff scientists and postdoctoral fellows from ForestGEO, including Stuart Davies, Eugenie Mas, Jose Medina, Krishna Anujan, Helene Muller-Landau, Luca Morreale, and Kelvin Acebron, attended the annual AGU (American Geophysical Union) conference in Washington, DC, on December 9-13. The conference is the “largest gathering of Earth and space scientists,” where individuals connect and share their research. The goal of the conference is to better understand the planet, environment, and how to address climate change. This year’s theme was “What’s Next for Science,” and it was attended by approximately 27,000 registered guests. ForesGEO post-doc Krishna Anujan presented a poster, “Sensitivity of tree growth to precipitation in seasonally dry tropical forests using long-term dendrometer band measurements”.