Saturday, April 5, 2008
Representative, Board of Directors, Association of Monterey Bay Area Governments
Paul Michel, Superintendent, Monterey Bay National Marine Sanctuary
Moderator: Chris Harrold, Director of Conservation Research, Monterey Bay Aquarium
Professor Lisa C. Sloan, Department of Earth and Planetary Sciences, Director of Climate Change and Impacts Laboratory, University of California Santa Cruz, Santa Cruz, CA
An overview of current knowledge and issues of global climate change and the relation to oceanic processes and states; including recent climate modeling studies that provide likely scenarios for the future climate conditions in California and the central coast with likely impacts of these climate changes upon human and natural systems.
Dr. Douglas Smith Science and Environmental Policy, California State University, Monterey Bay
Global sea level rose and fell over 20 times during the past 2 million years, in concert with a long series of ice ages and intervening warm periods. The most recent sea level low-stand occurred about 18,000 years ago (18 ka) when the most recent ice age drained the oceans to a level about 120 m (400 ft) lower than today. Global sea level has been generally rising since the 18 ka year low stand, but at an unconstant rate. The rise was generally rapid until 5000 years ago. The rate has generally been less than 10 cm/yr since that time.
Local shoreline position is a balance of global sea level, coastal tectonics, and coastal sediment supply. The shoreline along Monterey Bay has been generally moving inland with the global rise in sea level, but estuarine sediments near Gonzales, CA show that the shoreline reached far up the Salinas Valley about 8000 years ago. Increased sedimentation outpaced sea level rise, and the shoreline moved seaward before a growing delta system at the mouth of the Salinas valley. Sea level then drowned the delta and has probably been moving inland ever since.
Present effects of rising sea level in our area include estuary/lagoon formation in drowned river valleys, coastal flooding in low-gradient coastal valleys, and erosion along coastal bluffs and promontories. We captured the linked processes of natural coastal retreat and beach nourishment during the storm and high waves of early January 2008.
Continued sea level rise is a near certainty, given recent observations of polar ice. Under that scenario, the erosion and flooding effects will be amplified, and may include drowning of salt marsh environments if the rise outpaces vertical accretion of organic material. Beaches will disappear if coastal armoring is used to slow coastal erosion, but highways and urban infrastructure will have to be relocated if coastal retreat continues. Dike systems and levees are a popular way to locally and temporarily prevent peri-coastal flooding of suburbs or agricultural lands. Dedicated floodable lands (wetlands, marshes, and estuaries) may provide longer term protection than levees, and provide key habitat and resource values
Nicholas Welschmeyer, Moss Landing Marine Laboratories
The potential effects of increased atmospheric CO2 on ocean biota are not well understood. Recent monitoring programs have made it clear that oceanic CO2 concentrations have increased measurably, resulting in large scale ocean acidification, a process that may lower ocean pH by as much as 0.4 pH units over the next 100 years. For some biological processes, such as shell formation in calcifying organisms, the negative effects of ocean acidification are reasonably predictable. An attempt will be made to review the acidification process, summarizing the expected effects on calcification rates of those organisms characterized by calcium carbonate hardparts, e.g., corals, coccolithophorids, pteropods, etc.
Unfortunately, the effects of CO2 and pH on other important biological processes, such as oceanic photosynthesis, are not necessarily predictable. In the terrestrial realm, a significant body of literature has amassed showing that even under conditions of increased global CO2 the ambient atmospheric CO2 concentration remains low relative to the photosynthetic demand of terrestrial higher land plants. The current increase in CO2 has been demonstrated to have a well-known "fertilization" effect on higher land plant photosynthesis. In the ocean, the corresponding case is not clear. Some experiments have shown positive effects of CO2 on photosynthetic rates of marine phytoplankton, whereas other studies show no effects. Moreover, recent experiments have shown that under suitably high doses of CO2 the physiological processes of photo protection, ATP production and oxygen evolution in phytoplankton can be adversely disrupted to the point that cell death occurs. Thus, under specific conditions, we can expect toxic, biocidal effects of CO2 on marine phytoplankton. These processes are not well understood and it is apparent that there is a serious gap in our knowledge of the predicted effects of CO2 on oceanic primary production: is it a fertilizer or is it an herbicide?
William J. Sydeman, Farallon Institute for Advanced Ecosystem Research
In eastern boundary current systems, coastal upwelling is predicted to intensify as a result of increasing temperature gradients between land and sea. Along the U.S. west coast, atmospheric-oceanographic coupling in the past decade has been extremely variable, resulting in dramatic changes in the California Current large marine ecosystem (CCLME). In this presentation, I review physical and biological changes in the central eco-region of the CCLME, influenced primarily by upwelling from Pt. Arena, Pt. Sur. There have been considerable changes in primary to tertiary productivity, and the strong probability of altered seasonality, food webs and predator-prey relationships. Notably, inter-species comparisons for both fish and seabirds reveal an apparent dichotomy exists between inshore / neritic vs. offshore / pelagic species. This suggests that climate change may be causing upwelling-ecosystem relationships to vary by distance from the coast, or, alternatively, that other oceanographic processes, e.g., circulation, may be driving differences in offshore and nearshore ecosystem productivity. A new research initiative designed to couple large-scale and long-term nearshore and offshore programs is needed to fully resolve the possibility of differential climate change and ecosystem change relationships for neritic and pelagic habitats in the California Current.
Dr. Kenneth H. Coale, Director, Moss Landing Marine Laboratories
The Moss Landing Marine Laboratories have pioneered the study of iron and it's effects on the primary production of open ocean phytoplankton, the uptake of carbon dioxide and the connection to climate change. The development of open ocean iron enrichment experiments has transformed our understanding of open ocean food webs and provided powerful insights into the workings of pelagic ecosystems and the cycling of carbon and nutrients in the upper ocean. Since the first experiments over a decade ago several international and private groups have successfully attempted such experiments and some consistent results have emerged: phytoplankton production and biomass in HNLC systems are limited, by the availability of iron. Iron enrichment accelerates the uptake of carbon and increases the uptake of nitrate thus fueling new production. Dramatic shifts in ecosystem structure result, favoring larger diatom species. Other results are not as clear. Complexities of these experiments consistently point to the variable and dynamic role of microzooplankton grazing. Yet, even some of the questions these experiments have been designed to address, do not have answers. The behavior and exact effect of iron on these ecosystems is differentially expressed. The cycling of iron itself is not well constrained and little is known regarding the fate of carbon exported below the mixed layer. In spite of these uncertainties, global-ocean iron fertilization is now being proposed as a strategy to mitigate growing atmospheric carbon dioxide and global warming. This talk/discussion will focus on the development of the iron hypothesis and highlight that which is known and that which remains a mystery regarding open ocean iron enrichment experiments.
Will Travis, Executive Director, San Francisco Bay Conservation and Development Commission
The San Francisco Bay Conservation and Development Commission (BCDC) has taken the initiative to formulate a broad outline of a comprehensive strategy for addressing climate change by reducing greenhouse gas emissions and adapting to sea level rise in the Bay region. Will Travis, the Commission's executive director, will explain why global warming will have somewhat different impacts on San Francisco Bay and Monterey Bay, but how the ideas expressed in BCDC's suggestions for a regional strategy are nevertheless applicable to the Monterey Bay region.
Laura Strohm, Executive Director, The Sustainability Academy, Monterey