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Dr. Nancy Knowlton is the Chair for the Marine Science Department at the Smithsonian's National Museum of Natural History in Washington, DC. She also maintains a part-time position at the Smithsonian Tropical Research Institute in the Republic of Panama, where she pursues her interests in tropical marine ecosystems. She is widely recognized for her studies of marine diversity, and has been invited by the World Bank, the Natural History Museum in London, and Swedish and Taiwanese authorities to provide advice on this issue.
Dr. Knowlton's research focuses on the ecology and evolution of coral reef organisms. Her research draws on a variety of techniques, including molecular genetics, field studies, and mathematical modeling. She has worked for many years on the coral reefs of Panama and Jamaica, as well as in the Cape Verde Islands, the Indian Ocean, Brazil and throughout the Caribbean. Her analyses have led to the now widespread recognition that estimates of marine diversity are probably too low by a factor of ten. Her work has been featured by both national and international print, radio, and film media.
As Director of the CMBC, she is co-host of a three-year symposium series sponsored by the Alfred P. Sloan Foundation on Marine Biodiversity: the Known, the Unknown, and the Unknowable. She is also the PI for an NSF IGERT Grant (Interdisciplinary Graduate Education and Research Training) on Marine Biodiversity and Conservation, which applies many of the ALLP training ideas to graduate education.
More information on her teaching and research interests can be found
in these web pages:
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Life on Planet Ocean – Present, Past and Future
The oceans are vast, and it was long thought that people could not substantially affect them. It is now widely recognized, however, that humans have had major impacts on the biology, the physical conditions, and the chemistry of the oceans. In this talk I will describe the nature of these impacts, and what we need to do to restore ocean health.
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All Glaser Lectures are held in WC 130 from 12-2pm.
Topic for the course: Coral Reef Biodiversity and Conservation
The purpose of this course will be to provide a basic introduction to coral reefs – the organisms that build them, the organisms that live within them, the threats that reefs face, and what we can do about these threats. Topics to be covered include recent discoveries affecting our understanding of coral systematics, symbiosis, coral bleaching and disease, food webs, and marine protected areas.
- Lecture 1 – The Biology of Corals
Corals are the organisms that are primarily responsible for building coral reefs, and so it is important to understand their basic biology. They are relatively simple organisms, related to sea anemones. However, their evolutionary relationships are in a state of turmoil at all taxonomic levels. Ecologically, most corals are colonial and clonal due to their ready ability bud asexually, and hence have life histories based on size rather than age. Sexual reproduction is also common. Most corals are hermaphroditic, but only a few routinely self fertilize. Some corals release eggs and sperm into the water column (“broadcasters”), whereas other release only sperm, with the females guarding the developing embryos before release (“brooders”). Baby corals (planulae) typically settle on crustose coralline algae after a few days to several weeks. Nutritionally, corals both eat other organisms, which they capture with their tentacles, and are photosynthetic, thanks to their symbiotic dinoflagellates (zooxanthellae). They can be killed by a variety of physical and biological factors, including storms, sedimentation, competitors, predators and pathogens.
- Lecture 2 – Coral Reef Ecosystems
Even just corals themselves represent complex ecosystems, as they contain not only the corals and the symbiotic algae mentioned in the previous lecture, but also Bacteria, Archaea and Fungi, whose roles are much less well understood. Thus the coral “holobiont” contains all the major kingdoms of life. On a larger scale, the primary reef components are the benthic community (both sessile, sedentary and mobile) and the organisms that move in the water column above the reef. Trophically, these organisms include primary producers, herbivores, detritivores, filter feeders, decomposers, and carnivores. Together, they form a fantastically complex food web. But coral reefs are not just energy networks; they also form enormous physical structures. Finally, reef ecosystems are not isolated, but rather interconnected, not only with other reefs but also with nearby mangrove and seagrass communities.
- Lecture 3 – Coral Reef Biodiversity
Coral reefs are called the rainforests of the sea, in part because of their enormous diversity. That diversity is very poorly understood, as estimated numbers of species range from 1-9 million, the vast majority of which remain undescribed. Unlike rainforests, this diversity is spread across the animal kingdom, rather than being concentrated in a single group. Microbial diversity is also staggering, even within a single coral. In general reefs are more diverse near the equator, and on the western side of ocean basins – the Indowest Pacific, and within it the “coral triangle” are the most diverse. Many processes, both local and regional, contribute to species diversity patterns, which are the net result of species origination, maintenance and extinction. Over millions of years, reef diversity is associated with ecological stability.
- Lecture 4 – The Global Collapse of Coral Reefs
Reefs are among the most threatened of all marine ecosystems. Over the last thirty years, about 80% of coral reefs have been lost in the Caribbean, and recent analyses of Pacific reefs suggest a similarly serious trajectory. Indeed, much damage occurred before serious study of reefs began. The root causes now are both local (overharvesting of resources, poor water quality) and global (ocean warming and now acidification). These processes result in such phenomena as algal overgrowth, coral bleaching and disease. Not only are reefs declining in terms of coral cover, but they are also changing in terms of trophic structure and losing their resilience, that is, their ability to bounce back in response to natural disturbance. Seaweed dominated reefs may represent an alternate stable state which is difficult to escape from. Mass extinctions, caused by reproductive failure, are no longer impossible to imagine, although to date extinctions have been few. However, the situation is so dire that we may be in the early stages of paying an “extinction debt”.
- Lecture 5 - Coral Reef Conservation and Restoration
Coral reefs are important to conserve – they not only represent the most diverse of all marine ecosystems (with direct benefits ranging from tourism to pharmaceuticals), but they also provide food to many coastal peoples and shoreline protection. Given the dire current state and projections for global change, this is clearly a conservation emergency. Global efforts to reduce CO2 emissions are clearly essential, but there are also many indications that local protection makes reefs more resilient to global change. Networks of marine reserves, coupled with water quality control, are our best strategy for reef conservation. In addition, targeted protection of spawning grounds and herbivores can be effective strategies. No-take reserves, such as those established for the Great Barrier Reef and the North West Hawaiian Islands, are good tools, but other strategies are probably more effective in developing countries where most reefs are found. Reef restoration can be effective but only at small scales, and it is very expensive – the California Condor approach is clearly not an option for reefs overall. Methods exist to assist making conservation priorities. But the most important need is simply to do something, since so few reefs are protected now.
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