Greetings Alviso Adobe friends, 

Your monthly dose of nature and history is here for you! Although our indoor facilities remain closed, our outdoor open space known for its breathtaking views, luscious vegetation, and historical markers are awaiting your discovery.
 S T A Y  C O N N E C T E D
F O L L O W  us on F A C E B O O K F O L L O W us on F A C E B O O K
F O L L O W us on I N S T A G R A M F O L L O W us on I N S T A G R A M
V I S I T our W E B S I T E V I S I T our W E B S I T E


Fiat Lux: Nature's Way
by Naturalist, Martha Cerda

There is nothing quite like the twinkling of lights on these dark and long December nights. Festive lights decking people’s homes are sure brightening up the nights for many of us. The recent surge of dazzling lights got me thinking of the array of light displays out there in nature. Deep in the ocean and across our forest floors, nature has light of its own. There are two ways that organisms get their glow on, some have the ability to bioluminesce, others can fluoresce, and in some cases, they can do both. Here is the scoop on both processes:
  • Bioluminescence: A ‘mixing things up’ kind of process. Needs oxygen, a molecule called luciferin, and a fancy enzyme called luciferase. The outcome of this chemical reaction is a molecule known as oxyluciferin where electrons are in an excited state. After the electrons sizzle down, they release light, and the organism can emit its glow.
  • Fluorescence: A ‘light shining’ kind of process. Needs a molecule with excitable electrons and the right wavelength of incoming light for an organism to emit light. Since light fuels fluorescence, the glow is more intense when under high-energy radiation, like ultraviolet light.
Both bioluminescent and fluorescent organisms shine but, as we covered, it happens through different processes. Organisms use a variety of body parts to emit light in different colors and for different purposes. Some use their glow as a warning. Others use it to woo a potential mate. These natural spectacles are mesmerizing to learn about, but even more magnificent to experience.

December nights are perfect for night hikes. Typically during this time of year the Alviso Adobe Community Park offers after-dark treks through local Pleasanton trails. Once, before the start of a hike, I was asked if we were going to see fireflies. And while the short answer to that was not exactly, I did remind the group that nature is constantly glowing. All we need is a little bit of luck and to take a closer look at our surroundings. When most think of fireflies, the rapid classic flashing behavior of these beetles (yes, not flies), comes to mind. If you ever find yourself east of the Rocky Mountains on a late spring or early summer night you might catch the males performing the most important light show of their lives.

We might not have the ‘typical’ fireflies like they do east of the Rockies, but we do have firefly species across California. These 18 species are members of the Lampyridae family, a family of insects within the beetle order Coleoptera. A glowing member of this family includes the California Pink Glowworm (Micorphotus angustus) which uses bioluminescence to communicate. While adult males look like typical fireflies, females stay in their larval form their entire life. The adult female glowworms have a large, light-producing organ at the end of their abdomens. It is this neon-green light that glows and speaks to the male. You can find the California Pink Glowworm typically within oak woodlands, under oak leaf litter.
Bioluminescence and fluorescence are not restricted to the animal kingdom, it can be found across many taxonomic groups. Perhaps the most fascinating thing I learned this month was that the California Bay Laurel tree (Umbellularia californica) lights up! Not only does it spark our olfactory receptors with its quintessential sweet and minty leaves, but it truly glows. The bay nuts give off a greenish fluorescent hue under ultraviolet light. And apparently it is unknown what element causes this. Once I heard about this phenomenon, I had to see it. Take a look at this great nature mystery.
The natural world is full of organisms with the ability to light up or glow. Which do you think are bioluminescent and which are fluorescent? Answers down below in the 'Additional Resources' section. 
  • Western Banded Glowworm
  • California Glowworm
  • Western Jack-O-Lantern
  • Western Forest Scorpion
  • Flat Backed Millipede
There is so much to see out there that brightness up the night. If you are searching for some sparkle use iNaturalist to see where you can spot some of these luminous beauties near you and enjoy a natural light show.  


Trace the history of light from human control of fire, candles made out of fat, oil lamps, LED lights, and more with these short and informative resources. 


Embark on a digital tour to appreciate, celebrate, and preserve Pleasanton's heritage. Check out the Alviso Adobe Community Park's unique stories, videos, and historical pictures. Click here to begin your journey. 


Pigeon Post Highlight of the Month

When is the last time you hiked Augustin Bernal? With the little bit of rain we received, it might have been just enough to bring out the newts. 

Our pigeon post of the month is all about these bright creatures. Check out their question and our response. Thank you to our curious friend for staying connected with the Alviso Adobe! 
We want to hear from you! What's got you wondering? Send a postcard with your questions about local natural history - anything from wildlife to historic objects. One to two questions and responses will be posted here. 
Follow these 3 easy steps: 
1. Write a message! 
2. Personalize your postcard.
3. Include your address to
receive a response. 

Send your postcard to: 
Pigeon Post - Alviso Adobe
200 Old Bernal Avenue 
Pleasanton, CA. 94566


Catch our newest outdoor adventure! Explore history and the natural world as you discover 7 unique gems throughout the park.

Download the Adventure Lab App to get started! 

The adventure can be completed under an hour, with some extra time to explore outside. A low to moderate amount of walking is required to complete the course.


Answers to 'Fiat Lux: Nature's Way': 
  • Western Banded Glowworm - Bioluminescent
  • California Glowworm - Bioluminescent
  • Western Jack-O-Lantern - Bioluminescent
  • Western Forest Scorpion - Fluorescent
  • Flat Backed Millipede - Fluorescent
Visit the Virtual Library & Recreation Center for other Adobe resources and more. Here you'll find a great selection of free applications, online services and quality content that you can access from home. 
Alviso Adobe Community Park
3465 Old Foothill Road
Pleasanton, CA 94588

Closure of Non-Essential Facilities and City Government Meetings

Alameda County Public Health Department's current Health Order—issued on May 18, 2020—does not provide a sunset date for sheltering in place as previous Orders provided. Non-essential City services and facilities will be closed until further notice. For more information, and for live updates impacting our community, visit the City of Pleasanton COVID-19 Update Page.

Essential services that will remain available include Paratransit service to medical appointments and grocery stores only; Open Heart Kitchen's senior lunch program brown bag pick-up only; and Spectrum Community Services' Meals on Wheels. 

Contact our Staff:

Martha Cerda
Library and Recreation Coordinator/Naturalist

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City of Pleasanton · 3465 Old Foothill Road · PO Box 520 · Pleasanton, CA 94566 · USA