Beautiful and resilient: bluff country landscapes key for species survival as planet warms | Science & Environment

SAUK PRAIRIE — Nestled in the hills southeast of Baraboo, Hemlock Draw is like a time capsule from Mother Nature.

Descending roughly 300 feet into a gorge carved by water over millions of years, past quartzite outcrops that once stood as islands in a prehistoric sea, the oak and maple forests of southern Wisconsin give way to yellow birch, white pine and hemlock.

Typically found in northern Wisconsin, these trees are relics of the last ice age, when polar ice sheets ended just a few miles to the east.



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Ann Calhoun, Baraboo Hills project coordinator for The Nature Conservancy, walks past “sea stacks,” quartzite outcrops that were once islands in a prehistoric ocean at Hemlock Draw State Natural Area.




The glacier that covered most of Wisconsin — but not the southwest corner — retreated more than 10,000 years ago as global temperatures warmed by about 5 degrees Celsius. But on the shaded slopes of this gorge, conditions remained cool enough for those species to hang on.

Scientists think those same geological features that made southwest Wisconsin biologically resilient during the last period of climate change can help preserve biodiversity in the coming decades of unprecedented global warming.

Over the past decade, a team of scientists working with The Nature Conservancy analyzed geographical and topographical data across the United States to identify and map landscapes like the Baraboo Hills that they believe will be key to helping species survive.

Now the global nonprofit organization has made that data publicly available through an online mapping tool that will allow government agencies, nongovernmental organizations, private landowners and local leaders to develop conservation strategies that focus limited resources on the most valuable land.

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How do plants know when the environment is suitable for growth and when it is not?

plant
Credit: CC0 Public Domain

Plants use photosynthesis to convert sunlight, water and carbon dioxide to the sugars they need to grow and that ultimately feed our planet. Water is also essential for transporting nutrients from the soil and for providing rigidity to the tissues (turgor) so the plant can remain upright. Lack of water leads to drought and ultimately to plant death. Being such an essential factor, plants have developed mechanisms to monitor water availability in the soil and to communicate this information to distant tissues to induce appropriate adaptive responses. When water is scarce, the phytohormone abscisic acid is produced, inducing a very rapid closure of the pores in the leaves (stomata) to prevent water loss through transpiration. In addition, growth of most organs stops, so that resources can instead be used in protective measures. Until now how the lack of water resulted in growth arrest remained largely unknown.


A study led by Elena Baena-González, IGC principal investigator and member of the GREEN-IT Research Unit, uncovered the mechanisms by which this happens: abscisic acid signals are linked to a highly conserved regulatory system constituted by two protein kinases (SnRK1 and TOR), that control growth in all eukaryotes(animals, plants, fungi, and protists). “When conditions are favorable the accelerator of the system (TOR) is active, inducing biosynthetic processes, cell proliferation and growth. When conditions are unfavorable the break of the system (SnRK1) becomes active, inhibiting TOR and consequently growth” says Elena Baena-González. This ancient system is controlled in all eukaryotes by nutrient signals, resulting in growth arrest when nutrient levels (“fuel”) are low.

“However, we found that in plants this system is controlled by additional signals related to the water status (ABA), conferring plants the unique capacity to regulate growth not only in response to nutrient signals but also in response to water availability” explains the researcher. The team believes that this system may have been crucial for the establishment of terrestrial life by maintaining resource spending and growth to a minimum when water was scarce.

Using the model plant Arabidopsis thaliana, the researchers observed that when the SnRK1 kinase is genetically inactivated, plants develop larger roots under suboptimal conditions. Although such uncontrolled growth may be fatal under severe drought, it is likely to increase the capacity to absorb water from the more superficial soil layers, potentially improving plant growth when water is moderately limited. Future experiments work will aim to address these questions and to identify downstream factors that could be more amenable for manipulation of this trait also in crops.


Sulfate helps plants cope with water scarcity


More information:
Borja Belda-Palazón et al. A dual function of SnRK2 kinases in the regulation of SnRK1 and plant growth, Nature Plants (2020). DOI: 10.1038/s41477-020-00778-w

Provided by
Instituto Gulbenkian de Ciência (IGC)

Citation:
To grow or not to grow: How do plants know when the environment is suitable for growth and when it is not? (2020, October 20)
retrieved 20 October 2020
from https://phys.org/news/2020-10-environment-suitable-growth.html

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Groundbreaking study finds 13.3 quadrillion plastic fibers in California’s environment

A first-of-its-kind study in California has laid bare the staggering scale of pollution from plastic microfibers in synthetic clothing – one of the most widespread, yet largely invisible, forms of plastic waste.



Photograph: Rachel Ricotta/AP


© Provided by The Guardian
Photograph: Rachel Ricotta/AP

The report, whose findings were revealed exclusively by the Guardian, found that in 2019 an estimated 4,000 metric tons – or 13.3 quadrillion fibers – were released into California’s natural environment. The plastic fibers, which are less than 5mm in length, are primarily shed when we wash our yoga pants, stretchy jeans and fleece jackets and can easily enter oceans and waterways.

“The findings were nothing short of shocking,” said Alexis Jackson, fisheries project director at the Nature Conservancy in California, which commissioned the study from a research team at the University of California, Santa Barbara. The study has not yet been peer reviewed or published.

Many picture ocean plastic pollution as large debris such as bags, straws and bottles, but in fact the majority consists of tiny particles that accumulate in tiny organisms and rise in the food chain.

Their size makes it easy for them to collect in everything from plants to plankton. A recent study found that 73% of fish caught at mid-ocean depths in the Atlantic had microplastic in their stomachs.

The number – 13.3 quadrillion – is tricky to wrap one’s mind around, so the study’s authors have made more digestible comparisons: it’s as many fibers as there are stars in the Milky Way galaxy. It’s also equivalent to 80m rubber duckies’ worth of plastic polluting the state every year.

Thousands of plastic microfibers are shed when synthetic clothes get washed. The microfibers then surf through washing machines and end up in the wastewater stream. A 2016 study showed that an average-sized load of laundry could release more than 700,000 fibers into wastewater, though how much is shed depends on several factors: the type of garment, materials used, wash temperature and detergent. Currently, there are no washing machine filters that catch the particles.

Video: Giant “vacuum cleaner” for tiny plastic waste (Reuters)

Giant “vacuum cleaner” for tiny plastic waste

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These synthetic materials are unknown to the natural environment, so microbes and other creatures have not evolved to deal with them, says Roland Geyer, an industrial ecologist at UC Santa Barbara who collaborated on the report. “We are introducing these synthetic materials into the environment at a much larger scale than we initially thought. And that has people worried about the longer term environmental and health consequences.”

To come up with the final tally, the team combined data on synthetic fiber consumption with estimates of how often people wash their clothes, and how much those clothes shed in each wash. Then they used California-specific sludge and wastewater management information to follow the fibers and predict how many end up in bodies of water, landfills, incinerators or spread on land.

Wastewater plants have the ability to capture the fibers, but there’s

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