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Five Climate Tipping Points We've Already Seen, and One We're Hoping For

forestfireThis week is Climate Week in New York, when President Obama, Pope Francis, and many other world leaders converge to continue hammering out commitments intended to limit global warming to 2 degrees C or less, to be presented at the make-or-break COP21 climate meetings in Paris in early December.

The commitments are not there yet--so far those on the table would allow enough greenhouse gas emissions to raise temperature 3 degrees C or more. But staying below 2 degrees is critically important, for we already are seeing climate-triggered problems arise, even though global temperature has only risen less than one degree (0.9 degree C) above what used to be normal, and indeed what human civilization evolved in.

Read the rest at Huff Post Science Blog

UCMP and Stanford partner on a global change workshop for teachers

Teachers Monica Sircar (left; Everest Public High School, Redwood City) and Crystina Ayala (ASCEND K-8 School, Oakland) use string to represent rays of sunlight hitting Earth's surface at different angles at different latitudes.

Teachers Monica Sircar (left; Everest Public High School, Redwood City) and Crystina Ayala (ASCEND K-8 School, Oakland) use string to represent rays of sunlight hitting Earth's surface at different angles at different latitudes.

Middle and high school science teachers received double the resources when UCMP and Stanford's School of Earth, Energy & Environmental Sciences teamed up to offer a week-long workshop on global change.

Read more about the workshop on Stanford's blog

UCMP science casual: Dinosaur NightLife at the California Academy of Sciences

Imagine over 3,000 adults in San Francisco’s California Academy of Sciences (Cal Academy) for a night of fun special exhibits, drinks, and a serious science social. Now imagine it every Thursday. On July 23rd a dinosaur-themed Cal Academy NightLife event called upon volunteers from UCMP to showcase and explain the mysteries of these monsters beside their contemporary chews.

The NightLife also featured a tour of Cal Academy’s library archives about the historic “Bone Wars” between Victorian paleontologists Othniel Charles Marsh and Edward Drinker Cope and a showing of the 1993 classic Jurassic Park in the Tusher African Hall. Indeed, there was something uncannily familiar about watching the Dilophosaurus scene from Jurassic Park amongst stuffed African lions and cheetahs, who had also certainly taken their fair share of prey during life.

The event runs every Thursday from 6-10pm and requires a 21+ photo ID for entry. Stay tuned for the next time UCMP crosses the bay for another paleo-themed NightLife gathering!

New research shows how mammals became smaller in response to dramatic climate warming

Lead author Brian Rankin holds jaws of two species of 50 million year old horses.  Measurements of their teeth were used to study how global change can affect how mammals evolve.

Lead author Brian Rankin holds jaws of two species of 50 million year old horses. Measurements of their teeth were used to study how global change can affect how mammals evolve.

Fifty-six million years ago the Earth underwent a dramatic warming event, with temperatures increasing by as much as 7° Celsius over a span of just 100,000 years. Many mammals responded to this temperature increase by becoming much smaller. How these changes happened, however, is poorly understood. Identifying and measuring the mechanisms that drove these changes was the focus of a new study by University of California Museum of Paleontology researchers Brian Rankin and Pat Holroyd, and colleagues from University of Calgary and Western University of Health Sciences.

Lead author Brian Rankin, the newest postdoctoral scholar of University of California Museum of Paleontology, explains "When temperatures get warmer, we see a wide range of mammals become smaller. Determining what evolutionary processes are responsible for these changes and how much each contribute to this pattern has been very uncertain. We chose the evolution of mammals at the Paleocene-Eocene boundary because it is a time of dramatic global warming when many different types of animals became dwarfed and the fossil record of this time is incredibly rich."

In a new paper published in Proceedings of the Royal Society B, these researchers present a new method to separate and quantify body size change due to selective extinction vs. change within lineages to determine which is the most important way in which evolution takes place during times of global warming. They found that that some evolutionary mechanisms (i.e., species selection) might act differently during global warming events, favoring mammals that increase in size rather than decrease. The methods developed in the paper can now be broadly applied to look at evolutionary change during other times of global change.

Partnership with Point Reyes National Seashore leads to important discovery of marine specimen

ptreyes-fossilUCMP's partnership with Point Reyes National Seashore (National Park Service) has resulted in the discovery and collection of an important marine mammal specimen. This specimen is currently being prepared by UCMP Research Associate Robert Boessenecker, and will be reposited at UCMP. Lillian Pearson, a Geoscientist-in-the-Park intern, is setting up protocols for the long-term monitoring of paleontological resources (fossils) at Point Reyes. Erica Clites did this type of work for the National Park Service before coming to UCMP, and has been advising Lillian on the project. For more information, read the full story.

Barnosky meets with Governor Jerry Brown and a United Nations delegation to discuss climate change

On June 15, UCMP Curator and Integrative Biology Professor Tony Barnosky met with Governor Jerry Brown, Executive Secretary of the UN Framework Convention on Climate Change Christiana Figueres, and California climatologists at the Los Angeles County Museum of Natural History to discuss global warming and the consequences of failing to deal with it.

At a press conference following the meeting, Brown expressed his desire to reduce California’s greenhouse gas emissions by 40 per cent over the next 15 years and spoke of legislation mandating that 50 per cent of the State’s electricity come from renewable sources by 2050.

Brown et al

Behind Governor Brown (at the podium) are (from left) Christiana Figueres, Liz Hadley, and Tony Barnosky. Photo courtesy of Tony Barnosky.

At the end of November, representatives from some 195 countries will gather in Paris for a UN Climate Change Conference in the hope of forging international agreements to limit greenhouse gases and combat climate change.

See past blog posts dealing with Tony’s involvement with climate change issues.

UCMP participates in Girl Scouts’ “bridging” event

Every May for the past 30 years or so, the Girl Scouts of Northern California have celebrated the advancement of their scouts from Junior to Cadette status by a symbolic walk across the Golden Gate Bridge. Following this year’s May 2 event, the scouts continued on to Crissy Field where they enjoyed entertainment and information booths. And UCMP was there to celebrate with the scouts.

For the third year in a row, UCMP hosted a table staffed by an enthusiastic crew that included graduate student (and former Dutch girl scout) Renske Kirchholtes, undergraduates Gina Hwang and Alexis Williams, and Museum Scientist Erica Clites. The Girl Scouts and their parents enjoyed talking with current UC Berkeley students and seeing women role models.

Renske and Alexis

Graduate student Renske Kirchholtes and undergraduate Alexis Williams talk with members of a Girl Scout troop at Crissy Field. Photo by Erica Clites.

Alexis and Gina

Berkeley undergraduates (and UCMP employees on the USGS project) Alexis Williams (left) and Gina Hwang show fossils to eager Girl Scouts. Photo by Erica Clites.

A morphological study of living and fossil Quercus (oak) pollen from California using scanning electron microscopy

California has more than 26 oak (Quercus) species, many of which have widespread distributions and different habitats. For example, the California black oaks (Q. kelloggii) are distributed in foothills and low mountains (altitude ~4750 feet), while the Coast live oak (Q. agrifolia; altitude ~830 feet) lives near the coast. Palynologists study the distribution of plant pollen and spores in space and time, and changes in their assemblages reflect changes in regional and local vegetation.

Oak pollen

Oak pollen grain

In the study of past climates, palynologists have used oak pollen as an indicator of relatively warm environments. But in the examples given above, we see that the range of different oak species varies, so the temperatures in their respective habitats must vary as well. If palynologists treat all the oak species the same — as indicators of a "warm environment" — could this lead to wrong interpretations of the environmental conditions? If the answer is yes, why do palynologists still treat all the oak species the same?

This question could be answered if we resolve a basic problem in pollen taxonomy: how to distinguish between the pollen of different oak taxa. All oak pollen have similar characteristics: three colpi (furrows) and a verrucate surface (small surface features under two microns). Even the ratio of length and width of each species overlaps. These nearly uniform morphological features make identifying oak pollen very difficult at the species level, at least using Light Microscopy (LM).

I am studying pollen samples from Clear Lake to understand climate and vegetation change in California during the last interglacial period (~120-80 kyr ago). See earlier blogs: Dispatches from Clear Lake, part 1 and part 2; California pollen taphonomy and pollen trap study in Clear Lake, California. After studying the lower part of a 150-meter-long lake core that includes sediments from the interglacial period I'm interested in, I found two distinct oak pollen numerical peaks. Before categorizing all oak pollen in the samples as "indicators of warm environments," I would like to know which species of oak they represent. Since it's so difficult to detect morphological differences using Light Microscopy, I wondered if I could identify more diagnostic features on pollen grains using Scanning Electron Microscopy (SEM). Serendipitously, a paper was published on how to use SEM and quantitative analysis to identify grass pollen at the species level. Like oak pollen, grass pollen is also difficult to differentiate using LM identification. Thinking that the methods described in the article could be applied to oak pollen identification, I decided to take SEM images of California oak pollen to see if a systematic identification method could be developed. Then, I'd use quantitative analysis methods to identify the oak species in my Clear Lake interglacial samples and see if there were particular taxa appearing and/or disappearing in the area during times of climate change.

Last summer (July, 2014) I visited Dr. Luke Mander, author of the grass pollen paper, at the University of Exeter, UK, to investigate the possibility of identifying oak pollen using SEM and computer statistics. In an SEM lab, I took 70 images of pollen from 23 extant California oak taxa and 150 images of fossil California oak pollen.

Winnie with SEM

Winnie using the Scanning Electron Microscope.

A preliminary analysis has already revealed that at least three pollen wall morphotypes, two of which represent habitat-specific oak types, can be recognized in extant California oak species. Most specimens in Type-1 represent shrub oaks, adapted to dry environments. Type-3 pollen neatly matches specific phylogenetic lineages. We were able to assign the fossil oak pollen from Clear Lake to the three categories of extant California oak pollen. Interestingly, the change in oak pollen groups in Clear Lake sediments suggests species replacement during the start of the interglacial period. I have found that more precise and objective identification of oak pollen types is possible using automated digital image analysis algorithms and a larger training set of SEM photographs of pollen from known species, so I will be working on that in the Fall. I hope to amass more detailed vegetation analyses for past periods of climate change.

Pollen wall morphotypes

The three pollen wall morphotypes.

All photos courtesy of Winnie Hsiung.

Building a forest: The adventures continue in the Jose Creek Member

It's April 18, 2015, and I am sitting in a room at the Charles Motel in Truth or Consequences, New Mexico, the same apartment-style room that I have stayed in during the past four years of field work. Time sure has passed by quickly; from my first paleontological dig as an undergraduate at Texas State University-San Marcos under Dr. Gary Upchurch, to my ambitious inaugural self-guided field trip as a first-year graduate student at Berkeley, to last year's even longer field excursion, and finally to this short trip with my advisor, Cindy Looy. What keeps bringing me back to this area is an exceptional Late Cretaceous flora in the Jose Creek Member of the McRae Formation—this flora is the foundation of my dissertation work.

I am interested in the functional diversity (the range of plant ecological strategies) of Cretaceous forests in warm-wet climates. Cretaceous floras often contain a mix of plants that are no longer seen in association today. The Jose Creek assemblage, for example, includes both palms and redwoods. These non-analog communities can be difficult to understand from the perspective of community ecology, because we cannot make inferences about their ecology based on similarities in taxonomic composition with modern floras. The difficulty of understanding past communities is compounded by the paucity of fossil deposits preserving a "snapshot" of a forest in relative growth position. This is precisely why the Jose Creek deposit is so unique—it contains a flora preserved in a volcanic ash airfall. During my 2013 field season, we traced a single-horizon ash layer for approximately 1.2 km (see previous blog). Such an extensive deposit makes reconstruction of the forest, including lateral variation in forest structure, possible. Because the volcanic ashes are fine-grained and deposited rapidly, the plant parts (leaves, fruits, flowers, seeds, cones, etc.) are very well preserved. I am using morphological features of these plant fossils—and an explicit ecological and spatial sampling scheme—to reconstruct the forest. My ultimate goal is to evaluate the ecological diversity of the community, and to understand how forests in warm-wet climates have changed since the Late Cretaceous.

Leaf specimens and Dori

Assorted leaf specimens found at the Jose Creek site, and Dori, happy to have found a cone attached to conifer foliage. Leaf photos by Dori Contreras; photo of Dori by Stephanie Ranks.

This is what brings me to Truth or Consequences this April—a continuation of my quest to describe this incredible flora. This trip is a short one—only four days—with two simple missions: (1) "cherry picking" well-preserved leaf specimens to use for trait measurements (for inferences of their ecology), and (2) hunting for cones to finish a whole-plant description of an extinct redwood that is abundant in the deposit.

Last June's trip (2014) was more intensive. I drove to New Mexico with two undergraduates—James Buckel and Negin Sarami—and recent IB graduate/Looy Lab veteran, Stephanie Ranks. We spent two weeks working at the site, establishing new collecting quarries and re-sampling the 12 small exploratory quarries from the previous year, effectively doubling their size. All in all, we have now established 17 quarries that span the length of the exposure! We successfully employed a new data collection method in the field, which had several advantages over the previous year. During the 2013 collecting trip, we collected and brought back to the UCMP all of the specimens excavated from each quarry. This generated a large amount of material very quickly—the maximum that our extra-long SUV could carry. In contrast, during the 2014 trip we looked at all our excavated specimens, comparing them with a leaf morphotype guidebook of over 120 different leaf types that I created from the previous collections. Using the book as a guide, we were able to record the number of occurrences of each morphotype, as well as their percent cover of the rock surfaces, without having to bring every specimen back to the museum. Of course, we did collect the specimens that were very well-preserved or that represented new morphotypes. By adopting this method in the field, we were able to collect far more data than would have been possible by only making collections and still bring back a full load of really nice specimens to the museum.

Negin wrapping and labeling

Negin wrapping and labeling fossils to take back to UCMP. Photo by Dori Contreras.

Dori, Stephanie, and James

The field crew: Dori, Stephanie, and James (Negin not pictured). Photo by CJ at the Charles Motel and Hot Springs.

The flora has proven to be extremely diverse, with new morphotypes being found every day. The variation in morphotype composition from quarry to quarry also suggests a very structurally diverse flora. This is an incredible site to work, never a dull moment! I am really looking forward to the next big trip, and consider myself extremely lucky to receive the support of so many organizations, especially the UCMP and its amazing community of researchers, staff, and donors. Now, back to the field site before I lose any more daylight—Cindy and I still have a day of "wow" moments ahead of us before we return to Berkeley!

Organizations that have generously supported this work include:
— UCMP Graduate Student Award, University of California Museum of Paleontology, 2013 and 2014
— Geological Society of America Graduate Student Research Grant, 2014
— Integrative Biology Graduate Research Fund, 2014
— Sigma Xi Grants-in-Aid of Research, UC-Berkeley Chapter, 2014
— Mid-American Paleontological Society (MAPS) Outstanding Student Research Award, 2013
— GRAC Research Funds, UC-Berkeley Integrative Biology Department, 2013

Do green tide algae reproduce all year?

Occurrences of green tides have been on the rise in recent years worldwide. The most impressive have been reported off the coast of China in the Yellow Sea. In August 2014, the Monterey Bay area experienced a green tide that resulted in the accumulation of the macroalgae, Ulva, on its beaches. Algal blooms often make the headlines in spring and summer yet they are not a new phenomenon. In fact, toxic algal blooms may have been responsible for bird, fish and marine mammal die-offs recorded in the fossil records of Chile's Neogene and Gulf Coastal Florida's Pliocene. Blooms are typically considered to be an indication of decreased ocean health and pollution but there are many other factors that contribute to algal blooms. While Ulva itself doesn't produce toxic chemicals as it grows, the bacteria that decompose the alga once it begins to die can suck the oxygen from the surrounding seawater, suffocating other marine life.

Environmental factors necessary to generate an algal bloom include:

— Sunlight
— High nutrients
— Calm water
— Few grazers or predators
— Temperature
— Salinity

I've been interested in learning more about why we see green tides when we do. To do this, I've been focusing on the microscopic reproductive stages of the green-tide-forming algae, Ulva. In July 2014 I began collecting two liters of seawater every month from San Francisco Bay. I divide the water into culture flasks, add nutrients important to algal growth—such as nitrate, phosphate, ammonium, trace metals and vitamins—and culture it in environmental chambers on the UC Berkeley campus. These chambers are set to simulate summer conditions (16°C, 12-hour days) and every week I replace the seawater with fresh nutrient-enriched seawater. After four weeks I find young Ulva blades and tubes growing on the bottom of my culture flasks. Since I know the volume of the water I originally put into the flasks, I can estimate the number of propagules per liter that were present at the time of collection. I've been repeating this sampling at an additional four locations within San Francisco Bay once every season to estimate variation in spatial distribution of these reproductive stages.

Collecting water samples

I collect monthly water samples from the San Francisco Bay at the Romberg Tiburon Center. Each season I visit four additional locations within the bay to estimate spatial variation in reproductive stage abundances.

Every cell in adult Ulva (blade or tube) has the potential to become reproductive, releasing up to 16 swimming spores from each cell. The cells along the margins of the blades usually become reproductive first; you can see the difference in color between the reproductive cells and vegetative cells in the image at right, below.

Left: These algae (<1cm) grew from reproductive cells of Ulva, also known as sea lettuce. Right: There is a color difference between reproductive and vegetative cells in Ulva. The former are the lighter ones along the margins.

Left: These algae (<1cm) grew from reproductive cells of Ulva, also known as sea lettuce. Right: There is a color difference between reproductive and vegetative cells in Ulva. The former are the lighter ones along the margins.[/caption] Along with the help of some UC Berkeley undergraduates, I am also tracking the settlement of young Ulva at my field site in Tiburon. We have attached settling plates made of resin to rocks in the intertidal zone near the Romberg Tiburon Center. These settling plates are submerged at high tide and exposed at low tide. Each month we return to the intertidal at low tide to collect the plates covered in algae and replace them with sterilized plates. Once back at the lab we use a dissecting microscope to estimate the amount of young Ulva growing on the plates. Now we are working on comparing the amount of young Ulva that grows in the cultures to the patterns of young Ulva we are seeing on the settling plates.

[caption id="attachment_3955" align="aligncenter" width="470"]Algae established on a settling plate A quantity of algae has established itself on this settling plate.

All photos courtesy of Rosemary Romero.