Updates: Despite the global pandemic, the Davidson lab moves forward with what research can be done from the safe confines of our homes and computers. Sarah Albright continues to develop and test a device to measure the tensile force of different algae in her garage. By examining the tensile force, she can test the biomechanical properties of different algae species and sizes. Ultimately, we hope we can infer how algae species and size may influence fragmentation, a method that some invasive algae use to disperse and propagate. Ethan Roberts (now recently graduated!) has moved onto a job with the state where he helps to monitor and control invasive weeds. We're sad to see him go, but happy to hear of his successes. He continues to analyze and write up his research on the environmental effects of isopod burrows. Davidson has been hard at work analyzing and writing up research from his mangrove research on introduced Hawaii mangroves and project examining the biogeography of invasive shipworm borers. We're all looking forward to returning to the field next season (hopefully) when the infection risk gets low enough. Until then, we'll isolate, keep working on our computer-based projects, and keep wearing our masks.
Good news: I am happy to announce a new paper published in Science Activities called "Leaf detective: using evidence of damage on mangrove leaves to measure the effects of different herbivores." In this lesson, elementary students examine real mangrove leaves (digitized) to infer which organism(s) caused the damage they observe. They practice making a scientific question, collect data, graph, and then make a conclusion based on scientific evidence. This lesson represents several years of work and testing in both Sacramento and Hawaii elementary classrooms. My Hawaii collaborators and I are happy that we can share this lesson idea with K-6 teachers. Please email me for a copy, if you do not have access through the link above. And teachers are welcome to contact me if you wish to discuss ideas on how to adapt it to an online learning environment.
I hope everyone stays safe and vigilant. Wearing a mask saves lives!
Congratulations to Ethan Roberts who won 2nd place at the CSUS Spring Symposium for his talk: "Burrows created by an ecosystem engineer improve survivorship of intertidal invertebrates". Congrats also to Sarah Albright, who successfully completed her Advancement to MS candidacy. Other lab members are also working diligently, such as Jessica Nichols who is analyzing mounds of field data, and Jenna Grossman who is helping Sarah with algae fragmentation studies and beginning to design her own project.
In other news, I am honored to receive the university's Outstanding Teaching Award for the college of NSM. I appreciate the support of my colleagues and students! I do love teaching as much as I love research. I am continuing to analyze data exploring how herbivory varies in introduced and native mangroves and collaborating with a Hawaii elementary school teacher and a former post doc adviser to develop curriculum for K-6 teachers using mangroves as a model system.
Finally, back in January my wife and I traveled to the Galapagos Islands! It was an amazing trip and I'd recommend every biologist and nature lover to visit some time. It is one of the few places that felt pristine with a diversity of huge tree-like cactus, giant tortoises, strange tropical penguins, and an unparalleled wealth of marine life...including of course, my favorite: the beautiful Sally lightfoot crab. We have still to fully sort through over 1000 photos we took...but here are a few samples. Enjoy!
The CSU COAST Undergraduate Student Research Award program at Sacramento State is currently accepting applications! Due Friday Dec 13 at 5pm.
Students can request up to $500 to cover supplies, travel, and other expenses for a research project related to marine, coastal, or coastal watershed ecosystems for 2019-20 (including summer). The application is located here.
Note: you will need to find a faculty research mentor at Sac State and then write a short proposal description (<500 words) and budget justification. I recommend writing your proposal in a text editor and getting feedback from your faculty mentor before submitting via the online system.
This summer lab member Sarah Albright spent every other weekend searching for native and non-native algae throughout San Francisco Bay. As preliminary research for her Master’s thesis, Sarah is creating a list of algae species residing in the Bay, and their current range. Some algae were found everywhere (such as Mastocarpus and Ulva), while others were only found in a few locations (such as at Oakland Port, where she found Codium fragile and Sargassum muticum).
Fig 1. Sarah carefully stepping along rocks covered in slimy Ulva spp. across from Oakland Port in order to reach the water’s edge, where Sargassum muticum has established alongside other introduced species of algae.
Sarah collected one specimen of each genus/species she could find during each trip and began to compile a small herbarium collection for future reference. These herbarium specimens will allow her to also take the time to more accurately ID individuals - though often, molecular analysis is required for identification to a species level. Nonetheless, these herbarium specimens can be used and archived should they become useful for another topic of interest at a later date.
Outreach with Del Oro High School students: Additionally, Sarah spent some time with Del Oro High School students in the field. These high school juniors and seniors learned ecological field survey techniques, become familiar with intertidal marine ecosystems and organisms, and assisted in real data collection for a Master’s Thesis.
Fig 2-4. Sarah training Del Oro High School students in the field identification of algae, how to create testable hypotheses from field observations, and field research concepts.
Guest contributor: Sarah Albright
This Summer, the Council of Oceanic Affairs, Science, and Technology (COAST) hosted undergraduate student internships at several of the 29 National Estuarine Research Reserves across the United States. Lab member Ethan Roberts spent his Summer interning with Jeff Crooks at the Tijuana River National Estuarine Research Reserve (TRNERR), where he helped analyze historical data and update species identification guides. The goal of his internship project was to make the job of identifying cryptic species easier by pointing out key features and making direct visual comparisons, so he took to creating illustrations with pencil and colored pencil.
In one of his pieces, Ethan used image editing software to group his drawings of the most common local goby species onto a single page and scaled them to life-size. The print will later be used by the TRNERR team during the Fall research season.
Ethan’s work is also novel in that it accounts for species not seen in San Diego previously. For example, some salt marsh habitats at TRNERR are now home to the Princely fiddler crab, Uca princeps, a large tropical visitor not found in any modern field guides (below). As global climate change continues, taking a second look over dated species guides and implementing visual tools may become important parts of doing good science.
Contributor: Ethan Roberts
COAST offers internships and other research opportunities for undergraduate and graduate students at Sacramento State and beyond! See here for details.
MS student Jessica Nichols and Davidson are preparing for a field trip to Rookery Bay, Florida to check on a field experiment. They are examining how wood-boring crustaceans and mollusks breakdown and alter structural complexity of wood debris in mangroves and the how such alterations may affect habitat use by other species. Last year, Nichols and Davidson (along with help from Dr. Andrew Altieri and CSUS student Anthony Ziba) deployed structurally complex wood habitat mimics (vulnerable to borers), identical habitat mimics made of fiberglass (impervious to borers), and control plots (no structure control).
New MS student Sarah Albright took a group of high school students to survey for invasive marine algae in San Francisco Bay. Sarah is interested in the role of fragmentation in facilitating invasion by invasive algae.
Finally, Ethan Roberts won 1st place at the Sacramento State Student Research & Creative Activity Spring Symposium. Ethan presented his updated results in his talk: "It's not the heat, it's the humidity: burrow
microhabitats created by a boring crustacean ameliorate stressful conditions in the intertidal." He received a small cash prize will be going on to to present his talk in a CSU-wide competition at CSU Fullerton later next month. Congrats to Ethan for his hard work!
The newest paper from the Davidson lab has been published in Ecology Letters:
Davidson TM, Altieri AH, Ruiz GM, Torchin ME. (2018) Bioerosion in a changing world: a conceptual framework. Ecology letters 21: 422–438 - Link
This review and synthesis paper examines how the process of bioerosion, the breakdown of hard substrata by organisms, affects the structure and biodiversity in ecosystems and the socioeconomics of human systems. Then it predicts how this process is exacerbated or mitigated by human impacts. Many different organisms from bacteria to elephants bioerode substrata and this widespread process occurs all over the world from the deep ocean to the tallest mountains. For example, bioeroders, such as sea urchins, breakdown coral reef or rock to create pits to live in, erosive crabs and rodents create burrows in marsh banks and levees, while others such as lichens may dissolve and grow into stone used in monuments and statues. Thus, this process can have large scale (and sometimes destructive) impacts to ecosystems and human-made infrastructure (such as docks and buildings).
Several human impacts, such as climate change, introductions of invasive species, and nutrient pollution are affecting bioerosion, which in turn can influence how these changes alter ecosystems and human infrastructure. However, these interactions are complex and interactive, and in many cases, we still do not have a strong understanding of how these human changes will influence bioerosion and future communities. Future work is needed to fully understand how bioerosion will be altered in an increasingly human-dominated world.
It has been a busy summer for the Davidson lab. My students, collaborators, and I have surveyed several estuaries on the Pacific coast (Coos Bay, Oregon, San Francisco Bay, and Panama canal zone, Panama) for wood boring invertebrates and are still working through the dozens of samples we obtained. Our preliminary data indicates that we may have even found a new invasive wood-borer in Coos Bay, Oregon, although we are still confirming those results.
A summer research student, Ethan Roberts, finished up an interesting study investigating how the burrows created by invasive boring isopods, Sphaeroma quoianum (image above), may provide a more buffered microhabitat for other species such as other isopods, amphipods, and snails. Through field and lab experiments, he found that burrow microhabitats are more humid and provide more desiccation resistance compared to exposed areas. These results suggest that these microhabitats may help marine animals better cope with desiccation stresses of living in the intertidal. During his studies, he also discovered dozens of individuals of New Zealand Mud Snails near Benicia in San Francisco Bay. It is unusual to find freshwater snails in such salty waters (10 ppt).
Finally, I have established pilot experiments for a new study seeking to understand how ecosystem engineering by wood-borers may influence community composition and diversity in San Francisco Bay. I hope this experiment will help provide key data in support of a grant proposal.