Undergraduates Calvin Munson ('19) and Maya Greenhill ('20) gave their first talks on their thesis research projects at the Charles Darwin Foundation. These talks presented preliminary research from the past two months of field work examining local to regional controls on sea floor productivity. At the regional scale, Calvin's work examines how the abundance of algae and invertebrates changes along gradients of upwelling in the Galápagos subtidal, in addition to how the diversity of herbivorous fishes affects ecosystem functioning in the form of resource utilization. At local scales, Maya's research is on damselfish territories as a major source of algal productivity on the rocky reef, focusing on species-specific differences in agal composition, depth zonation, and defense capacity that indicate complementarity in providing this important ecosystem function. Professor Jon Witman put these studies into context, summarizing and updating on how repeated El Niño/ La Niña cycles are shaping marine communities of benthic invertebrates and reef fish over 20 years of long term monitoring.   Surgeonfish and parrotfish school over the rocky reefs of Galapagos. The archipelago stood out among all others for its uniquely high biomass of herbivores and planktivores, evidence of its pristine state and productive waters. Photo: Maximillian Hirschfeld Robbie recently co-authored a paper on the biogeographic, energetic, and anthropogenic determinants of fish communities on tropical oceanic islands, believed to be some of the most pristine marine ecosystems left in the world. Below is the press release from Ecography.   A documentary called "Adapt or Die", about climate change impacts in the Galapagos Marine Reserve will be shown this Sunday, May 20, at 8pm - on CBS.
The documentary resulted from a CBS TV crew coming on our January research cruise, which they filmed along with several other researchers working in the region. It's CBS' streaming service (think netflix) so Sunday at 8 will be the full show, and after that the doc itself will be available online and in streaming (on any smart TV.) Disclaimer: we haven't seen it yet either!! Witman Lab undergraduate students Maya Greenhill and Calvin Munson receive UTRA research grants!4/4/2018
Maya's study, "Evaluating the ecological role of Damselfish species in the Galapagos Marine Reserve", will test the territory defense capacities of different damselfish species in a comparative analysis, and evaluate the importance of damselfish territories as a microhabitat and food resource. Calvin's study "Effects of grazer diversity and upwelling strength on ecosystem functioning in the Galapagos subtidal ecosystem" asks how variation in the richness and abundance of herbivores interacts with the upwelling of cold, nutrient-rich water to the surface (increasing primary productivity) to determine the richness, biomass, and resource utilization of benthic algae.
Congratulations to Maya and Calvin!  The Witman Lab's work describing the unique marine communities on Cashes Ledge in the Gulf of Maine was highlighted in "Our Daily Planet", a daily blog on the environmental, sustainability, and conservation. Read the article here, and check out the paper by Witman & Lamb that recently came out in Plos One.
We are excited to share our latest publication (Witman & Lamb 2018), "Persistent differences between coastal and offshore kelp forest communities in a warming Gulf of Maine", published in the journal Plos One. The article highlights the unique biomass and diversity of the Cashes Ledge kelp forest 145 km east of the New Hampshire coast. Cashes Ledge is home to the greatest density and biomass of Saccharina latissima kelp at this depth in the Western North Atlantic, and supports a biomass of fish 305 times greater than coastal sites. The shallow kelp forest communities offshore on Cashes Ledge represent an oasis of unusually high kelp and fish abundance in the region that is functionally significant for sustained biological productivity in the Gulf of Maine.  A. view of common macroalgae at the coastal site of Mingo Rock dominated by Agarum kelp and the invasiive Dasysiphonia japonica. B. Saccharina latissima kelp forest on Cashes Ledge. C. View of S. latissima, a foundation species, at Cashes Ledge. D. Patch of Saccharina digitata kelp at Cashes Ledge. E. Photo of a deteriorating assemblage of S. latissima kelp covered with white colonies of the invasive bryozoan Membranipora membranacea during the warm summer of 2012. Fish in the foreground are cunner (Tautogolabrus adspersus). Photo credits: A, B and D by Brett Seymour, C and E by Brian Skerry.  Participants of the workshop on climate change in the Galapagos pose for a picture, including Jon Witman (second from left, back row), Pelayo Salinas de Leon, Boris Worm, Daniel Pauly, and other members of the Charles Darwin Station, Galapagos National Park, visiting scientists, and the Ecuadorian navy.
One sign of stress was that massive and finger corals turned white (bleached) during a broad temperature regime ranging from 30 to 16 o C in 12 months as the cool nutrient rich La Nina period followed the warm phase. For example, chlorophyll a, a measure of planktonic food concentration increased 7-fold during La Nina. Thus the team speculated that the ecosystem bounces back a certain degree during La Ninas – rolling uphill on the coaster, demonstrating resilience. A surprisingly consistent response seen during all 3 La Nina events was that barnacles settled and grew all over the rocky bottom and on the stressed corals down to 20 m depth. This represents a boost to the food chain as many species of fish and snails feed on the barnacles. It appears that the La Nina- increased barnacles may be slowly displacing corals. While corals did not bleach as much as previous El Ninos during the strong 2015-2016 El Nino, we observed a diverse range of ecological impacts from skin disease in reef fish to intense sea urchin grazing and a bloom of cyanobacteria at some oceanic sites. Our work underscores the importance of sustained ecological monitoring to detect the impact of climate oscillations in the ocean.  Fiona poses with her poster at the Ivy League undergraduate research symposium Fiona Beltram traveled to the University of Pennsylvania for the inaugural Ivy League Undergraduate Research Symposium (ILURS). The symposium consisted of 200 undergraduate students from Ivy League schools who were involved in independent research at their respective schools. Most students presented posters, while others gave short talks. Guest lectures by University of Pennsylvania and visiting faculty were also arranged throughout the three-day conference. Research topics ranged from art history and public health to astronomy and cancer research. Fiona gave a poster presentation detailing the results of her current work, which will serve as the first two chapters of her thesis for honors in the Biology degree. She is studying the appearance of cyanobacterial mats on the Galapagos reefs, the potential for a temperature-mediated introduction mechanism that is closely tied to El Niño extremes, and the ecological effects of the species’ continued presence on the reef.
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