Please join Point Reyes National Seashore staff for Science Lectures, 45 minute presentations on scientific research being performed at Point Reyes and elsewhere in the California. Science Lectures are sponsored by the Pacific Coast Science and Learning Center at Point Reyes National Seashore. They usually occur at noon on many Thursdays throughout the year and are normally held at the Red Barn Classroom at Point Reyes National Seashore's Headquarters. All are welcome and admission is free.
Visit our Science Lectures page to learn about upcoming lectures.
Some of our Brown Bag Lectures in 2013 included:
Date: Thursday, December 12, 2013
Title: "Whale Shark Migrations in the Eastern Tropical Pacific."
Presenter: Alex Hearn, PhD, Director of Conservation Science, Turtle Island Restoration Network
Summary: Whale Sharks (Rhincodon typus) are the world's largest fish, reaching maximum reported lengths of 20 m. They are circumglobal and may be found in tropical and temperate waters. Predictable aggregations related to feeding occur at sites throughout the world, notable Ningaloo Reef (Australia), Gladden Spit (Belize) and Baja California and Yucatan (Mexico), and whale shark tourism has become an important source of income in many of these places. However, their ecology remains an enigma. Of a global total of 82 whale sharks fitted with satellite tags, only three were larger than 10 m, and most were males. Satellite tracks have shown whale sharks move long distances, and photo-ID techniques have shown that individuals return to specific locations after long absences, yet true migration, implying the movement away from a location over a long distance and a subsequent return, has not been recorded until now.
At Darwin Island (Galapagos Marine Reserve), large, apparently pregnant whale sharks are encountered consistently in low numbers from June through November each year. By photographing and tagging them we have found that they do not reside at the island throughout this period, rather, they travel past it out to the open ocean then migrate back through Darwin and on eastwards to the coast of South America, where they spend the summer months in the cold, nutrient-rich upwelling coastal waters off Peru. Darwin Island is an important waypoint in a regional migration undertaken by large, probably pregnant female whale sharks. Although only a small number of individuals are present at the site at any given time, up to several hundred individuals may pass through the site in a season. This is the first study which shows bona fide migration, with several individuals returning through Darwin after moving large distances into the open ocean, and establishes connectivity with mainland Ecuador and Peru.
Top of Page
Date: Thursday, November 14, 2013
Title: "Sea cave development in Point Reyes National Seashore - a half century perspective."
Presenter: Bruce Rogers (USGS ret.), President, Western Cave Conservancy
Summary: Observation during the past 50 years at Point Reyes have shown that this location is rich in sea caves and associated features. The majority of sea caves have formed in the porcellanite of the Miocene Monterey Formation (~17.5–6 million years old [Ma]) with lesser numbers in the Cretaceous (96–82 Ma) granitic rocks including tonalite, granodiorite, and granite. Faults and major joint sets related to the San Andreas and San Gregorio Faults have guided development of the caves. These sea caves range from shallow grottos to lengthy catacombs and are prime refugia for marine life. Varying beach sand levels both allow and block access to some caves seasonally. In view of the current sea level having stabilized in the Central California coast area at about 7,000 years ago, it is assumed most of the sea caves are younger than that time. In at least one instance, however, the cave may be older and represents a rejuvenated feature perhaps as much as 125,000 years old. Coastal erosion has both been the driving force in the formation of the sea caves and their modification, and eventual destruction. In turn, some of the sea caves appear to be major forces in coastal erosion in the softer Tertiary rocks. In addition to being major littoral marine life sanctuaries, there are sparse, secondary decorations within the caves that are analogous to those in limestone/marble caves. In addition to the sea caves, tafoni shelters are present in the calcareous sandstone of both the Miocene (12–10 Ma) Santa Margarita Sandstone and (~15–11 Ma) Laird Sandstone.
Bruce Rogers began cave exploring in New England in the 1950's. Since then he has explored the basements of North and Mesoamerica in addition to many of the island nations of the Pacific Basin. His wide-ranging spelean interests encompass mineralogy, geology, & geography, paleontology, cartography, and history. He is the author of numerous publications on caves and related subjects, usually illustrated with his own photographs and drawings. Bruce is a Fellow of several scientific societies. Since the early 1970's, increasingly restricted access to caves prompted his interest in conservation. As long-time supporter of conservation efforts, he brings a nation-wide perspective to the caving community. His interest in caves led to a formal education in geology and a position as a field geologist at the U.S. Geological Survey in Menlo Park, CA, as well as cooperative earth science programs at the National Park Service and NASA. He is now retired after 8 years working in private geoscience and engineering firms and 33 years of Federal service.
Top of Page
Date: Wednesday, November 13, 2013
Title: "Invasive Plant-Soil Interactions and Implications for Dune Restoration and native species at Point Reyes National Seashore."
Presenter: Sarah Winsemius, UC Berkeley and Point Reyes National Seashore Association
Date: Thursday, October 24, 2013
Title: "Lagunitas Creek DIDSON (Dual frequency IDentification SONar): Using Sound to Monitor Coho Salmon."
Presenter: Ben Atencio, Point Reyes National Seashore Association
Date: Thursday, September 19, 2013
Title: "Marine Plastic Pollution in Sea Turtle Habitat - California to Costa Rica."
Presenter: Chris Pincetich, Ph.D., Outreach & Education Manager, Turtle Island Restoration Network
Date: Thursday, June 6, 2013
Title: "Biological diversity of an Endangered Community: the Abbott's Lagoon Insect Inventory."
Presenter: Paul DaSilva, College of Marin
Top of Page
Date: Thursday, May 2, 2013
Title: "What can natural disturbance regimes tell us about effects of global change? A macroecological case study with Pinus muricata."
Presenter: Erica Newman, UC Berkeley
Date: Thursday, April 18, 2013
Title: "Disrupting the flow: Effects of stream fragmentation on juvenile steelhead ecology."
Presenter: Jason Hwan, UC Berkeley
Date: Thursday, April 4, 2013
Title: "Straight from the hippo's mouth: an investigation of hippopotamus ecology and the people that investigate it."
Presenters: Lacey Hughey and Dylan Voeller, UC Berkeley
Summary: Though one of the largest land mammals in existence today, there has been relatively little research into the ecology and behavior of the common hippopotamus. In response, a team of UC Berkeley researchers has set up camp in Laikipia, Kenya, in hopes of elucidating some of the mysteries that link these peculiar giants with the greater river ecosystem. Attendees learned what the researchers have discovered so far and got a glimpse into the life of a field biologist in the Kenyan bush.
Website: Mpala Research Centre and Mpala Wildlife Foundation
Date: Tuesday, April 2, 2013
Title: "The Bay Delta Conservation Plan"
Presenter: Jerry Meral, Ph.D., Deputy Secretary of the California Natural Resources Agency
Website: Bay Delta Conservation Plan
Date: Thursday, January 31, 2013
Title: "Natural History of Antarctica."
Presenter: Gary Fellers, US Geological Survey
Top of Page