Bacteria can anticipate the seasons: Photoperiodism in cyanobacteria
Long-lived plants and animals clearly regulate their physiology according to seasonal changes in day length to appropriately adjust their physiology.
Jabbur et al. found that cyanobacteria can do the same even though individuals only live for a few hours, a time shorter than a single daily photoperiod. Exposure to short photoperiods characteristic of winter stimulated these cyanobacteria to adjust their membrane lipids and gene expression to accommodate cold conditions. These responses required a functional circadian clock. Thus, population-based sensing of photoperiod appears to have evolved early, perhaps as a refinement of stress pathways. — L. Bryan Ray | Science
Journal Reference:
Maria Luísa Jabbur et al. ‘Bacteria can anticipate the seasons: Photoperiodism in cyanobacteria’, Science 385, pp.1105-1111 (2024). DOI:10.1126/science.ado8588
Centennial-Scale Intensification of Wet and Dry Extremes in North America
Drought and pluvial extremes are defined as deviations from typical climatology; however, background climatology can shift over time in a non-stationary climate, impacting interpretations of extremes.
This study evaluated trends in meteorological drought and pluvial extremes by merging tree-ring reconstructions, observations, and climate-model simulations spanning 850–2100 CE across North America to determine whether modern and projected future precipitation lies outside the range of natural climate variability.
Our results found widespread and spatially consistent exacerbation of drought and pluvial extremes, especially summer drought and winter pluvials, with drying in the west and south, wetting trends in the northeast, and intensification of both extremes across the east and north.
Our study suggests that climate change has already shifted precipitation climatology beyond pre-Industrial climatology and is projected to further intensify ongoing shifts.
Journal Reference:
Sung, K., Bohrer, G., & Stagge, J. H., ‘Centennial‐scale intensification of wet and dry extremes in North America’, Geophysical Research Letters 51, e2023GL107400 (2024). DOI: 10.1029/2023GL107400
What is a heat wave: A survey and literature synthesis of heat wave definitions across the United States
Heat waves are the last extreme weather events without a formal, on the books, definition.
Instead, across the U.S. those working on extreme heat event management, forecasting, and planning are using differing definitions in their work. With such differing definitions being used there are widespread impacts including some to human and environmental health, natural resource management, and long-term emergency management planning.
For instance, when should heat advisories for vulnerable populations be released when an event impacts a region using multiple definitions? There are concrete and justifiable reasons for the lack of a formal heat wave definition including, at its simplest, differences in what temperature is extreme enough, compared to the region’s climatological regimens, to be deemed as an extreme heat event or heat wave.
This study looks for patterns and commonalities in emergency managers and climatologists, those most commonly addressing or planning for such events, definition of heat wave events through a review of the literature and widespread survey across the United States. Through a short 11-questions survey and subsequent text mining, we find widespread variability in the common heat wave definitions but a consistent pattern of core key term usage including aspects of heat duration, extreme temperature, and humidity. However, we also see little to no usage of non-climatological variables such as exposure, vulnerability, population, and land cover/land use.
Journal Reference:
Bunting EL, Tolmanov V, Keellings D, ‘What is a heat wave: A survey and literature synthesis of heat wave definitions across the United States’, PLOS Climate 3(9): e0000468 (2024). DOI: 10.1371/journal.pclm.0000468
Charting the future of high forest low deforestation jurisdictions
This study highlights the importance of protecting high forest low deforestation jurisdictions (HFLDs) against future deforestation. Such deforestation could release substantial carbon into the atmosphere. Our findings have shown that it is insufficient to base market-based carbon financing on historical deforestation rates. Advances in baselining methods are necessary to achieve adequate market-based carbon financing. By using an empirical multifactorial model, we identify the HFLDs at the highest risk of future deforestation. This emphasizes the need for better baselines to protect these vital forests and mitigate the impact of deforestation on climate change.
Journal Reference:
Hoong Chen Teo, Tasya Vadya Sarira, Audrey R. P. Tan, Yanyan Cheng, and Lian Pin Koh, ‘Charting the future of high forest low deforestation jurisdictions’, PNAS 121(37): e2306496121 (2024). DOI: 10.1073/pnas.2306496121
Bottled water, tap water and household-treated tap water–insight into potential health risks and aesthetic concerns in drinking water
Understanding drinking water quality at the point-of-use across a range of consumer options is essential for designing effective public health interventions in the face of deteriorating source waters and complex contaminant mixtures. This is especially pressing as the popularity of tap water alternatives like bottled water and household treatment increases, yet this data is largely missing from the academic literature and policy discussions.
This study presents one of the first evaluations of water quality comparing three common consumer drinking water options in the nine county San Francisco Bay Area with a survey of 100 analytes in 100 bottled water samples, 603 tap water samples, and 111 samples of household-treated tap water.
Analytes measured included general water quality characteristics, metals, other inorganics, volatile organic compounds (including disinfection byproducts), and three microbial indicator species in bottled water only. Samples were evaluated to assess potential taste, odor, and color issues, as well as potential health risks by calculating cumulative toxicity quotients to reflect the additive toxicity of chemical mixtures.
All three drinking water options had potential health risks, primarily driven by the presence of trihalomethanes (contributing from 76.7 to 94.5% of the total cumulative toxicity across the three drinking water options). While tap water had the highest potential toxicity among the three drinking water options, results suggest that household-scale treatment may reduce the potential for aesthetic issues and health risks of tap water.
Journal Reference:
Bear SE, Waxenberg T, Schroeder CR, Goddard JJ, ‘Bottled water, tap water and household-treated tap water–insight into potential health risks and aesthetic concerns in drinking water’, PLOS Water 3(9): e0000272 (2024). DOI: 10.1371/journal.pwat.0000272
Flower Power: providing blooms all season long may be the key to attracting pollinators, no matter what landscape your garden is near
A diverse and abundant flower planting that provides flowers in bloom all season may be more important to bees and other pollinators than whatever is surrounding the flower garden, according to a study published September 4, 2024 in the open-access journal PLOS ONE by Devon Eldridge from the University of Tennessee, US, and colleagues.
As we learn more about how critical pollinators (native and non-native bees, butterflies, and other insects) are to our food supply and ecosystem, many people are planting pollinator-attractive flower gardens to help sustain these important and threatened creatures. Eldridge and co-authors investigated if and how the context of these gardens (e.g. the surrounding local context and broader land-use factors) may impact the attractiveness of flower gardens for different bee species.
The authors worked with four types of garden: three planted solely with plants from just one family – Asteraceae (daisies), Fabaceae (legumes), or Lamiaceae (mints) – and one garden composed of a mixture of plants from all three families.
They replicated all four garden types at five different sites representing a variety of surrounding land use: urban garden, forage grassland, mixed agriculture, forest, and organic farm. From July 13-August 17 2020, they then sampled bee species in the garden plots as well as conducted local surveys within a 50 m radius of each garden on a weekly basis.
The authors collected 1,186 bees across 44 different bee species during 20.83 hours of sampling in the garden plots. When surveying the local areas surrounding the garden test plots, the authors collected 2,917 bees representing 52 different species over 16.67 total hours.
The mixed agriculture garden site had the highest bee abundance among the specific garden surveys, while the area surrounding the urban garden site had the highest abundance among the surrounding local area surveys. Individual plants’ floral display (the number of flowers available on a plant) and the diversity of flowers in the wider local area did not affect bee abundance or species richness within the garden plots.
Although there was a positive association between developed land use in a 2 km radius and bee abundance in the gardens, the effect was small. The largest determinants of bee community composition and species richness in the gardens were floral display size and variation in the garden plant species in bloom.
The authors note that all of their garden sites were located within “patchy”, heterogeneous landscapes, and that gardens surrounded by habitats with more extreme and/or different land-use might show different results.
Nevertheless, these results suggest that landowners have the power to promote local pollinator communities by conserving existing natural patches and/or planting more flowers, especially groups of flowers to provide blooms all season long—no matter what environment their garden may be situated near.
The authors add: “We often wonder how the area surrounding our gardens affects the pollinators visiting our flowers. In our study, we found that the number and types of flowers in the garden itself mattered more to pollinator abundance and diversity than the surrounding local or landscape context.”
Journal Reference:
Eldridge DS, Khalil A, Moulton JK, Russo L, ‘Do local and landscape context affect the attractiveness of flower gardens to bees?’ PLoS ONE 19(9): e0309000 (2024). DOI: 10.1371/journal.pone.0309000
Featured image credit: kjpargeter | Freepik
