Serpentine Sunsets - Ring Mountain

This past Saturday a small group got to experience a very special evening on Ring Mountain in Tiburon, CA. Under the setting sun participants explored a serpentine habitat containing multiple rare plants including one of the most stunning wildflowers in California: Calochortus tiburonensis. After sunset, moth lights were use to examine what flying insects occur in the area. 

Ring Mountain is a geological, botanical, and conservation wonder. The ridge that makes up Ring Mountain is composed of rocks from the subduction event between the continental plate and the ancestor of the Juan de Fuca plate. The smashing and mixing of material took place at extremely high pressure, but low temperatures and somehow made its way back to the surface quickly creating the crest of Tiburon. It is some of the highest grade metamorphic rock in Northern California and a large portion of it is serpentinite, a mineral low in calcium, high in magnesium, and nickel, which gives the stone is blueish shimmer. Serpentine soils are notoriously difficult places for plants to grow as plants require calcium and the soil also does not hold water well, so tends to be very dry on top of being nutrient deficient. Other common minerals in the area are lawsonite, glaucophane, jadeite and actinolite. Blue schist is the name applied to the ensemble of these minerals and large lumps of it are dotted around Ring Mountain in stupendous boulders; turtle rock, petroglyph rock, and split rock are just a few of the notable large chunks. 

 Split Rock, one of the stunning examples of metamorphic rock on Ring Mountain

Split Rock, one of the stunning examples of metamorphic rock on Ring Mountain

The serpentinite rich soils on Ring Mountain are inhabited by a number or novel plants that have evolved to deal with the difficult soils, some of which can be seen only on Ring Mountain and no place else in the world. The Tiburon Mariposa Lily (Calochortus tiburonensis) is the most famous of the rare plants on the mountain due to its rather large and intricate flower. C. tiburonensis wasn't discovered and named until the early 1970s, which is amazing considering most of the bay area had already been well surveyed by botanists for over 100 years. The relatively small plot of land and a narrow bloom time is most likely what allowed it to avoid detection for so long. Other notable plants in the area are the Marin Dwarf Flax, Pitted onion, cream sacs, Tiburon buckwheat, and Long ray brodiaea.

Moths are an important pollinator for plants but on most nature walks go unseen, since many of them fly under the cover of darkness to keep themselves out of the reach of birds and other predators. The existing species list for Ring Mountain has been compiled primarily by a handful of visits by Jerry Powell, Professor of Systematic Entomology at UC Berkeley, over approximately 30 years, but could use updating. Moths for reasons that are still unclear are attracted to lights. Three lights were set up at different locations for the evening and participants got a chance to see some of these invisible inhabitants. Damon was running a cheap DIY Moth light accessible for beginners, Donald was running a LepiLED, and Ken-ichi was running a BioQuip setup. A number of moths visited the lights through the hour we spent after sunset and some can seen below. 

Ring Mountain is a biological and geological jewel of the Bay Area and it sits on some of the most expensive land in the country. It is only due to the foresight and work of many agencies that this piece of land has been preserved for all to enjoy and didn't turn into a track of homes. In 1983 the Nature Conservancy acquired the land after a long battle with developers and over a decade later turned over the parcel to Marin County Parks to manage, which continues the stewardship by protecting the geological, archaeological, and biological riches of this unique space. 


Proposal for new A's stadium next to Lake Merritt and Laney College: Resources and articles

In light of the recent proposal by the Oakland A's to build a new stadium right next to Lake Merritt and Laney College, we're posting some resources and articles about the issue.

This project has CCNH and many other organizations concerned about how a very large, high-traffic stadium in the area would negatively impact communities, wildlife, and the gem of Oakland.

***Update from Dec. 6, 2017***: The Peralta Board of Trustees has voted to reject the stadium plan at Laney and has directed Chancellor Jowel Laguerre to halt further conversation with the A's. Though the Board of Trustees vote is a decided victory, the stadium plan is not completely scuttled.

We still need to show up at the Peralta Board meeting on Tuesday, Dec. 12 to show our support for the Board's decision and demand that Chancellor Laguerre comply with the Board's direction.

Stay tuned for more news, and visit for calls to action and other updates.

Learn more about the issue:

Video from the September meeting of the Peralta Board of Trustees (Oakland North)

What you can do:

  • Come to the Peralta Board of Trustees meeting on Dec. 12 to oppose the stadium.
  • Follow StAy The Right Way, a coalition of Chinatown and Eastlake residents, community organizations, small businesses, Laney community of students, staff and faculty, and environmental advocates who oppose the Peralta site for the new stadium mega development.
  • Tell the Peralta Colleges what issues they should consider in the community engagement plan for the proposed construction of a new A's stadium by Lake Merritt.
  • Sign the petition to oppose the stadium plan.
  • E-mail the Peralta Board of Directors:
    • Bill Withrow <>
    • Julina Bonilla <>
    • Linda Handy <>
    • Nicky Gonzalez Yuen <>
    • Dr. William “Bill” Riley <>
    • Karen Weinstein PhD <>
    • Meredith Brown <>
    • Nesi More <>
    • Corey Hollis <>

What's Living In Lake Merritt? A lot, it turns out.

 Hedgpeth's Sapsucker, a photosynthetic sea slug that lives in Lake Merritt. Photo:&nbsp;Damon Tighe

Hedgpeth's Sapsucker, a photosynthetic sea slug that lives in Lake Merritt. Photo: Damon Tighe

"Come check out some cool Lake Merritt creatures!" 

It seems like a hard sell at first, given how much people watching there is to do at the Lake. Lake Merritt on a sunny weekend afternoon is packed with families and friends, joggers, bicyclists, drummers, dancers, ice cream vendors with their tinkling bells.  Still, curious folks come to our table  to see the shallow tubs we've set up - a PopUp Aquarium - which allows them to see and touch some of the Lake's lesser known inhabitants: tube worms, bubble snails, tunicates, hydroids, anemones... 

Reactions follow a predictable pattern: shock, followed by wariness, and then finally, amazement.

First people express disbelief that anything lives in the Lake. Long-time Oaklanders have not-so-fond memories of the Lake as smelly and full of trash. Since Measure DD funds were put to use water quality has improved and marine life has increased.  Large fish like bat rays, striped bass, and sturgeon have been seen in the Lake. In August,  a harbor seal was spotted in the Lake. Seals and other large marine animals feast on smaller fish and mollusks like the ones we are showing off in our PopUp Aquarium. 

"So these creatures come from the Lake?", people ask. I point to a spot near the shore where I had waded in, wearing my rubber boots. "I pulled this rock up right over there, and these anemones were on it!"


 Orange-Striped Green Sea Anemone. Photo: Damon Tighe

Orange-Striped Green Sea Anemone. Photo: Damon Tighe


Everything in the tanks is touchable, nothing will bite or sting enough to hurt a person. Still, it takes coaxing for folks to put their hands in the water. I pull out a compressible yellow-grey blob and place it gently in their hands. "What does it feel like?", I ask. "It feels like a sponge." That's because it is a sponge! Sponges are some of the simplest animals on Earth. They grow in small clumps on the docks along the Lake. 

After they connect with one creature, people become more comfortable. It's time to introduce the sea vase tunicate. The sea vase is a translucent cylinder with two translucent tubes arms branching from one side. When I pull one out of the tank, the tubes retract. Its surface is perfectly smooth and soft, like a peeled grape. Pressed gently, water squirts from the lower tube. This never fails to delight. Maybe you've heard the phrase "sea squirt"?  Weirder: of all the animals we are displaying- snails, shrimps, worms- the sea vase is the closest relative to humans. In its larval stage, the sea vase has a rudimentary notochord, a structure shared by all vertebrates. In human embryos the notochord becomes part of our vertebral column. Tunicates have no backbone. Their notochord is reabsorbed as the creature develops, leaving the adult a gelatinous, boneless glob.  Still, it's a glob that shares a common ancestor with us!

 Sea Vase Tunicate. Photo: Damon Tighe

Sea Vase Tunicate. Photo: Damon Tighe

Within a few minutes, folks become believers. The fear of getting their hands wet is long gone. They notice incredible details of the structure and habits of the wildlife. "What's that? Why is it doing that? Is that a shrimp?" It dawns on them that Lake Merritt is full of amazing creatures, and it's been right here this whole time. People leave our table genuinely excited about what they've seen and learned. They continue their stroll or their jog with a newfound appreciation. All in all, a great afternoon at Lake Merritt.


We get lots of questions at our PopUp Aquariums. Here are a few common questions we fielded last week:

How did Lake Merritt form? During the last Ice Age, some 10,000 years ago, a channel was created that connected a low-lying area to the San Francisco Bay. Bay water flowed in and out with the tides, resulting in a salty marsh surrounded by mudflats. Human development in the last few centuries has dramatically impacted the landscape and ecosystem. Mudflats have been removed.  Nonnative species  have entered the waterway, often hitching a ride from distant lands via ballast water of international shipping tankers coming to the Port of Oakland.

Is Lake Merritt salty water or fresh? Both. Storm drains bring "fresh" water in the form of street runoff into the Lake. It's a mix of rain-water and all the nasty junk thats on the street (trash, dog poop, motor oil, plastic). If it's on the street, it flows into the Lake! Salt water comes in with the tides through the channel at the south end. Salinity in the Lake varies by time of year - less salty during the rainy season, saltier in the dry season. 

Are there fish in the Lake? Yes, I'm just not fast enough to catch them with my bare hands. There are lots of small bait fish living in the Lake. You can see brown pelicans dive-bombing from the air to catch them! Larger fish have been seen, too. Keep your eyes pealed.

Where did you get this stuff? We mostly collect samples from pier pilings and from rocks along the shore. Mussels and algae grow in clumps which act as a microhabitat for other organisms like worms, barnacles, tunicates and anemones. We try to return creatures as close as possible to where we found them. 

What kind of shellfish did the Native Americans eat?  Ohlone people lived along the marshy banks for thousands of years. They ate clams, mussels, and oysters and amassed the shells into massive heaps known as shellmounds.  Hundreds of shellmounds were documented around the Bay, including one at Lake Merritt. Some of these were also sacred burial places and ceremonial sites. For more information about shellmounds, check out the fight to preserve the West Berkeley Shellmound.

Is the Lake getting cleaner? Yes. The restoration of Lake Merritt is ongoing. The Lake Merritt Weed Warriors meet each month to plant and maintain native saltmarsh plants, which restore habitat and nutrients for other Lake dwellers. You can join them at a work day!



DIY Moth Light

DIY Moth Light

If you are attracted to seeing ephemeral organisms and like staying up late into the night doing so, moth lighting might be the past time you’ve been looking for. Don’t worry long hikes aren’t necessary, but there is a key piece of equipment that will make your new found sweat-less hobby more fruitful; a moth light....learn to build one here

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Back to school: Enroll now for Natural History courses at Merritt

Merritt College in Oakland provides great natural history courses. For the Fall semester we're recommending three courses for anyone interested in California ecology and natural history. All of these classes have field trip components, so they're perfect for hands-on learners and folks who want to get out of the classroom. Click the links to view the course fliers. Enroll through the Peralta Community College system here.