John M. Melack - US grants

The University of California at Santa Barbara maintains a field station in the eastern Sierra Nevada mountains for research and teaching in the field sciences. The Sierra Nevada Aquatic Research Laboratory (SNARL) serves as a base for many scientists working in east-central California and western Nevada. In addition, SNARL protects a variety of terrestrial and freshwater habitats for teaching and research use. This project will provide funds to construct fifteen medium- sized experimental stream channels to augment the existing stream and pond system at SNARL. The new channels will fill an important gap in the scale of experimental units available at SNARL, which currently has only small laboratory and field channels and a series of large field channels which were formed by division of an existing natural stream. The new, medium-sized field channels will allow investigators to examine the effects of spatial scale on the outcomes of experimental manipulations. The channels will simulate the physical, chemical and biological characteristics of natural streams while providing sufficient replication for rigorous experimental designs. Although the existing stream channels at SNARL do not provide sufficient replication for most experiments, they are still a realistic and important component of the battery of experimental units at the site. Therefore, the project also provides funds to repair the concrete control structures on the existing experimental stream system.

Lakes constitute nearly half of inland waters by volume and provide ecologically important habitats in arid regions. They often have high rates of productivity which support higher trophic levels, especially birds. At Mono Lake, California, environmental concern has focused on the threat to increasing salinity accompanying diversions of freshwater streams out of the watershed. State agencies have now conditioned Los Angeles water rights to raise and maintain the surface elevation of Mono Lake at a level significantly higher than the present. The ecological response to different lake levels and salinities is uncertain. During the past 16 years, Mono Lake s plankton dynamics were dominated by large changes in nutrient availability. Salinity bioassays on individual organisms and modeling studies predict higher primary and secondary productivity at the lower salinities accompanying higher surface elevations. However, recent analysis of sediment cores indicate little correlation between changes in salinity over the past 170 years and organic matter accumulation in the sediments. Thi s research will determine the response to change in salinity through key limnological measurements during the anticipated period of rising lake levels and decreasing salinity,will directly compare the resulting long-term record of plankton dynamics to the sedimentary record, and includes analysis of a 150-200 year sedimentary record for which lake level and salinity estimates are available. The comparison between the 21-yr record of plankton dynamics and organic matter accumulation in the sediments will be enhanced through contemporaneous measurements of sinking fluxes. Saline lakes are increasingly threatened by human-caused changes in salinity. The proposed research not only addresses the impact of changing salinity at Mono Lake, but also contributes to interpreting the sedimentary record of other lakes. Additionally, this research will advance efforts at.understanding the effect of species diversity on basic functioning of ecosystems. There are no comparable records for large, temperate, relatively deep, species poor lakes with which to compare to well-studied, species-rich, temperate lakes. This research will help to fill that void.

This study will establish an LTER (Long-Term Ecological Research) site in Santa Barbara, CA that will focus on ecological systems at the land/ocean-margin. This location is typical of many semi-arid regions in that it includes a large number of watersheds with episodic stream flow that vary in size and land use. The focal coastal ecosystem will be giant kelp (Macrocystis pyrifera) forests, which are extremely important to the ecology and economy of coastal areas along the West Coast of North and South America. Kelp forests occur on shallow coastal reefs and are affected in both positive and negative ways by land and open ocean through the movement of water carrying constituents (e.g. sediments, nutrients, larvae, pollutants) from these different sources. Kelp forests have a unique trophic structure in which producers (macroalgae) and consumers (sessile invertebrates that filter plankton) compete for space. Competition between macroalgae and sessile invertebrates can be mediated by the relative supply of nutrients and particulate organic matter to the reef. Although several lines of evidence suggest that the effects of terrestrial runoff on kelp forests in the Santa Barbara Channel can be large, the relative contributions of land vs. ocean derived constituents in structuring this and other coastal ecosystems in the region is poorly understood.
Interdisciplinary research coordinated among 22 investigators will examine questions and hypotheses related to all five core areas of research shared by LTER sites. The key issues that will specifically be addressed are (1) spatial and temporal scales over which terrestrial runoff and ocean forcing perturbs kelp forest ecosystems, (2) patterns and processing of organic matter in the ecosystem, (3) patterns of organic and inorganic inputs and their movement from the land to the coastal zone, (4) the effects of terrestrial runoff on patterns and controls of primary production in kelp forests, and (5) the effects of terrestrial runoff on the long-term population dynamics of key kelp-forest species and on trophic interactions. Regional studies will combine satellite imagery and field measurements of discharge from 3 primary and 12 secondary watersheds with modeling of solute and sediment-discharge relationships to determine patterns of runoff entering the Santa Barbara Channel. Detailed sampling of water chemistry and short and long-term experiments will be done in the three primary watersheds to determine smaller scale processes that are critical in controlling overall export to coastal waters. Satellite imagery combined with detailed measurements of ocean currents, waves, suspended sediment, subsurface irradiance, and seawater chemistry collected from moored instruments in the kelp beds offshore of the three primary catchments will be used to determine the timing, spatial extent, and residence time of runoff in the coastal zone and the degree to which they are modified by ocean processes. The effects of runoff on patterns of primary production will be investigated for both phytoplankton and macroalgae (the two major groups of primary producers found in kelp forests). Phytoplankton production will be estimated from optical data collected from moored instruments and satellites, chlorophyll concentration data collected from moored instruments and ocean cruises and C14 uptake experiments. Kelp production will be estimated from in situ measurements of growth and survival of tagged individuals and aerial photos of surface canopy area. Experiments will be done to evaluate factors that control primary production and the degree to which they are influenced by land and ocean processes. Short and long-term experiments and modeling will be performed to determine the extent to which changes in nutrient supply due to runoff alter trophic interactions of the unique food web.

The project will examine biogeochemical and hydrological mechanisms that influence the extent of N limitation in alpine and chaparral ecosystems of the Sierra Nevada, California. These ecosystems exhibit large, episodic losses of nitrate and their future integrity is threatened by climate change and nearby human activities. The investigators hypothesize that a key factor controlling N-losses in these ecosystems is the effect of transitions between growing and non-growing seasons on microbial populations and biogeochemical processes in soils during non-growing seasons. Seasonal transitions in Mediterranean climates, like those of California, are characterized by abrupt shifts from dry to wet conditions, warm to cold temperatures and from low to high runoff periods. These transitions induce changes in soil moisture and temperature that mediate flushing of nitrate. Over the long-term, nitrate losses during seasonal transitions may be a primary mechanism by which N limitation is maintained in alpine and chaparral ecosystems.
The project will take a watershed approach to studying N dynamics in alpine and chaparral ecosystems and will utilize a combination of innovative techniques, including plot-scale studies, isotopic and chemical tracers, watershed mass balances and ecosystem modeling. Results from these investigations will help explain a major question in terrestrial ecology: Why are plant communities N limited? Additionally, the work will provide an understanding of the connections between hydrology and biogeochemistry during seasonal transitions, which is needed to predict how California's montane ecosystems will respond to anticipated global change.

This award supports the acquisition of an isotope ratio mass spectrometer (IRMS) to be shared by a group of UC Santa Barbara investigators who have made extensive use of stable isotope analysis in their research programs. The new IRMS system will permit high-precision measurement of carbon, nitrogen, sulfur, oxygen, and hydrogen stable isotope ratios. The instrument would be configured to allow isotope measurements on solid samples of biological and geological origin, on both major and minor components of gas samples, and on purge-able gaseous, liquid, and ionic solutes in aqueous solutions. The instrument will be used in research that addresses a wide range of important and timely topics, including: measurements of fundamental microbial processes in marine environments, atmospheric methane levels, nutrient dynamics in soils from a variety of ecosystems and environments; and nutrient and food web linkages within coastal ecosystems. The instrument will be housed and maintained in a professionally managed, shared-use analytical and instrumentation facility at the University's Marine Science Institute. Besides providing a tool that is critical to the success of vital research programs, this equipment would also allow graduate student and postdoctoral users to become experts in this key technology for environmental science.

The Santa Barbara Coastal LTER (SBC LTER) is an interdisciplinary research and education program established in April, 2000 to investigate the relative importance of land and ocean processes in structuring ecosystems at the land-sea margin. The principal study area is the Santa Barbara Channel and the coastal watersheds that drain into it, and the focal ecosystem is giant kelp forests, which occur on shallow rocky reefs at the interface of the land-sea margin throughout the study area and other temperate coasts throughout the world. The major focus of the work proposed here is developing a predictive understanding of the structural and functional responses of giant kelp forest ecosystems to environmental forcing from the land and the sea. The amount of nutrients and organic matter delivered to the kelp forest from land and the surrounding ocean varies in response to short- and long-term changes in climate, ocean conditions and land use. Variation in the supply of these commodities interacts with physical disturbance to influence the abundance and species composition of the forest inhabitants and the ecological services that they provide. The overarching question of the proposed research is: How do abiotic drivers acting over different spatial and temporal scales interact to influence kelp forest structure and function?

To address this question the investigators will focus research around three general themes: (1) The influence of abiotic press and pulse drivers on rates of delivery of N and C to giant kelp forests, (2) The direct and interactive effects of key press and pulse drivers on kelp forest community structure and function through the modification of nutrient supply and wave disturbance, and (3) The indirect effects of pulse and press drivers on kelp forest community structure and function and the feedbacks between structure and function. The research will take advantage of a variety of approaches that include: (1) Coordinated long-term measurements of key abiotic drivers and ecological response variables, (2) Manipulative field experiments designed to isolate the causal mechanisms underlying the patterns observed in long-term measurements, (3) Measurement-intensive process studies aimed at obtaining a mechanistic understanding of processes that cannot be isolated using manipulative experiments, and (4) Integrated synthesis using modeling and analyses that allow for predictions beyond the spatial and temporal scope of SBC data, and that help guide the direction of future research. These efforts will be facilitated by SBC LTER's information management system which focuses on data organization integrity and preservation as well as provision of web-based access to a variety of different users.

Education and training are tightly integrated into all aspects of the research. The scientists/educators have successfully developed a multifaceted, interdisciplinary approach to education and outreach that highlights and integrates the research interests of SBC LTER investigators, students, and the general public. The programs include active links with K-12 students and teachers, graduate and undergraduate student training, direct public outreach, and productive interactions with the media, local NGOs and agencies. The outreach and education programs will continue to expand during the next six years as collaborations mature and attract additional support from participants and agencies. This interdisciplinary group of scientists are committed to sharing research findings with resource managers, decision makers, stakeholders, and the general public who are interested in applying the findings to policy issues concerning natural resources, coastal management, and land use.

Recent advances in microbiology have underscored the dominant role of bacteria in regulating ecosystem processes. The research proposed here examines the relationship between bacterial diversity and ecosystem dynamics by determining experimentally how seasonal changes in bacterial communities in high-elevation lakes of the Sierra Nevada (California, USA) associate with changes in the composition and metabolism of dissolved organic matter. This study expands on previous dissertation work demonstrating predictable bacterial community changes in these environments and linking community shifts to snowmelt-driven changes in organic matter composition.
Regional climate shifts are predicted to significantly affect snowmelt dynamics, and atmospheric deposition of nutrients in the western U.S. is leading to gradual eutrophication (excess nutrients) of montane lakes, many of which are located in protected areas. In collaboration with the National Park Service, the USDA-Forest Service, and the California Air Resources Board the results of this work will inform regional efforts to manage water quality and the maintenance of natural ecosystem function. Finally, by defining temporal dynamics of bacteria in the context of catchment organic matter supply & composition, seasonal lake transitions, and the character and rate of inflowing microbial communities, we aim to develop the first mechanistic illustration of bacterial changes linked to landscape-scale ecosystem processes.

Lake and stream ecosystems integrate conditions within their catchments and regional climatic changes. Results of prior studies in high elevation aquatic ecosystems of the Sierra Nevada have indicated changes in the importance of phosphorus to biological activity. The proposed research will test the hypothesis that the changing snow regime and atmospheric inputs of phosphorus are driving ecological changes in high elevation lakes. Continued measurements of chemical and biological conditions in lakes and streams in the southern Sierra Nevada, application of advanced techniques to determine atmospheric inputs, and analyses of phosphorus biogeochemistry in soils and sediments will be conducted to test the hypothesis.
High elevation lakes are excellent indicators of regional environmental changes and are increasingly being used by regulatory agencies to establish critical loads for atmospheric pollutants. Further, the importance of montane snowpacks to freshwater supplies of the western states mandates that particular attention be paid to these systems. Continuation of more than two decades of meteorological, hydrological, chemical and biological measurements in sites at high elevation will increase their value as detectors of conditions as regional variations occur. The proposed studies will continue to be used by the National Park Service in interpretative programs to demonstrate the role of scientific research in the National Parks. Engagement of local high school students in the studies fosters an interest in natural environments and encourages these students to attend college and pursue professional careers.

The Sierra Nevada Aquatic Research Laboratory of the University of California, Santa Barbara is awarded a grant to renovate and modernize an existing 279 sq. m. (3000 sq. ft.) laboratory building constructed in 1962. The building's layout and fixtures are outdated and limit the research of the station, and the structure is energy inefficient and in need of safety upgrades. Development of modernized laboratory facilities at SNARL will result in substantial new bench space and expanded research and instructional activities. Research projects that employ modern molecular and biogeochemical approaches will become feasible. Adequate space for laboratory components of experimental studies in the stream channels at SNARL will become available. Intensive field classes that utilize the rich diversity of aquatic and terrestrial habitats in the area and offer laboratory space for analyses will be valuable curricular additions.

SNARL is located near Mammoth Lakes, California along the eastern escarpment of the Sierra Nevada. The station was established in 1935 and since 1973 has been a unit in the University of California's Natural Reserve System. It serves as an experimental site and as a base of operations for research across a large part of the Sierra Nevada, eastern California and western Nevada. Researchers from throughout the US are regular users of the facilities, and the studies range widely among the life and physical sciences. By commonly used metrics (user-days, publications in peer-reviewed journals) the station is intensively used and very productive. Additional information about SNARL may be found at http://vesr.ucnrs.org/.

Three major fires occurred in the foothills and mountains above the greater Santa Barbara area in 2008 and 2009, all within watersheds with on-going, multiyear measurements. Because high rainfall is expected during the El Nino conditions forecasted for 2009-2010, burned ecosystems will show their greatest responses this year and afford an excellent opportunity to examine the effects of fire on terrestrial and stream ecosystems. Measurements will be made of short-term changes in burned and unburned watersheds, comparing the influence of fires on a variety of ecological and environmental responses including: stream discharge and the export of sediment and nutrients, soil movement and landslides, re-growth of vegetation at the watershed-scale using high resolution remote sensing and at the transect-scale by direct measurements of re-sprouting plants, and stream biota and ecosystem processes.

Modeling will permit prediction of flooding, soil movements, and stream water quality across a range of climatic conditions during post-fire periods. This information will be of value to natural resource managers and public safety officials. Participation in public meetings will further disseminate the findings. In addition, three graduate and four undergraduate students will gain invaluable experience in watershed ecology, hydrology and management.

Intellectual Merit:
The Santa Barbara Coastal LTER (SBC) is an interdisciplinary research and education program established in April, 2000 to investigate the role of land and ocean processes in structuring ecosystems at the land-sea margin. The main study area is the Santa Barbara Channel and the steep coastal watersheds, small estuaries and sandy beaches that drain into it. The focal ecosystem of the research is giant kelp forests, a diverse and highly productive marine ecosystem that occurs on shallow rocky reefs at the interface of the land-sea margin in the Santa Barbara Channel and other temperate regions throughout the world. The major emphasis of this project is developing a predictive understanding of the structural and functional responses of giant kelp forest ecosystems to environmental forcing from the land and the sea. The amount of nutrients and organic matter delivered to the kelp forest from land and the surrounding ocean varies in response to changes in climate, ocean conditions and land use. Variation in the supply of these commodities interacts with physical disturbance to influence the abundance and species composition of kelp forest inhabitants and the ecological services that they provide. The overarching question motivating this research is: How are the structure and function of kelp forests and their material exchange with adjacent land and ocean ecosystems altered by disturbance and climate?

To address this question LTER researchers will focus on three themes: (1) biotic and abiotic drivers of kelp forest structure and function, (2) material exchange at the land-ocean margin, and (3) movement and fluxes of inorganic and organic matter in the coastal ocean. The relevance of this research is far reaching as LTER scientists are addressing fundamental questions pertaining to biodiversity and ecosystem function, vulnerability and resilience of communities to climate change and fishing, the roles of land use and fire on landscape change and watershed hydrology, and the physics of dispersal in the little studied coastal waters of the inner continental shelf. The dynamic nature of kelp forests, including their frequent disturbance and rapid regeneration coupled with high productivity and diverse food webs make them ideal systems for investigating ecological questions that require decades to centuries to address in other ecosystems. This project will utilize a variety of approaches including: (1) coordinated long-term measurements, (2) manipulative field experiments, (3) measurement-intensive process studies, and (4) integrated synthetic analyses and modeling that allow for predictions beyond the spatial and temporal scope of our measurements, and help guide future research. SBC's information management system, which focuses on data organization, integrity, preservation and web-based public access geared for a variety of end users will facilitate these efforts.

Broader Impacts:
Education and training are tightly integrated into all aspects of this research. LTER personnel have successfully developed a multifaceted, interdisciplinary approach to education and outreach that highlights research interests of SBC investigators, students, and the general public. Programs include active links with K-12 students and teachers that target historically under-represented groups from under serving, low-achieving schools. The LTER participants are also very proactive in undergraduate and graduate student training, direct public outreach, and productive interactions with the media, government agencies and local industries. The LTER will continue these outreach and education programs and maintain efforts to attract additional funding to support them. The LTER is committed to sharing research results with resource managers, decision makers, stakeholders, and the general public who are interested in applying our findings to policy issues concerning natural resources, coastal management, and land use.

Long-term investigation of Emerald Lake and neighboring lakes and watersheds in the Sierra Nevada (California) are transforming our understanding of how mountain ecosystems are responding to global change. The proposed research will test the hypothesis that altered climate, changing snow regime, and changes in atmospheric composition are driving biogeochemical and ecological changes in high elevation ecosystems. Data to test this hypothesis will come from studies of lake metabolism, continued assessment of the response of lake phytoplankton to changing atmospheric deposition, continued study of the coupling between climate variability and nitrogen and phosphorus biogeochemistry, enhanced measurements of atmospheric deposition, and paleolimnological study of lake sediments. This research will build on more than two decades of biological, meteorological, hydrological, and chemical measurements in high elevation sites.

Management of National Parks and Wilderness Areas in the Sierra Nevada will benefit from the results of our research. The analyses and reconstructions will provide valuable information to Federal and State scientists on long-term lake changes and likely future responses of high elevation aquatic ecosystems to climate change. This research will provide training for one graduate student at UC Riverside in the interdisciplinary study of paleoclimatology and one graduate student at UC Santa Barbara. There will be active recruitment for these students at Minority Serving Institutions of higher learning. A strong outreach program developed with Woodlake High School in Tulare County (Central Valley agricultural region) will be expanded using field experiences and data from the proposed paleo-investigations and climate reconstructions.

Material exchange between ecosystems is being increasingly recognized as an important determinant of many ecological patterns and processes. Nowhere is this more evident than in the highly productive coastal zone, which receives large amounts of terrestrial particulate organic (POM) matter through stream and river discharge. In semi-arid regions such as southern California, the delivery of terrestrial POM to the nearshore is largely restricted to storm events that are intensified during El Nino years of above average rainfall. The processing and fate of this material is poorly known, yet there is growing evidence that it could contribute significantly to nearshore productivity. This research project will help to fill a critical knowledge gap pertaining to the origin, distribution, processing of terrestrial POM and its potential to serve as a reservoir of nitrogen storage for nearshore primary production during periods of the year when marine sources of dissolved inorganic nitrogen are low. Research on this award will be done in close collaboration with the Santa Barbara Coastal Long Term Ecological Research program (SBC LTER). As such it will augment SBC's strong contribution to student training and mentoring in interdisciplinary research at the undergraduate, graduate, and post-doctoral levels. Outcomes will be incorporated into SBC's ongoing Schoolyard LTER program, which is organized around a theme of kelp forest ecology and land-ocean exchanges and aimed at long-term connections with underserved, low-achieving schools that include year-round on and off campus activities. The LTER Investigators have developed formal partnerships with local cities and Santa Barbara County to develop vulnerability assessments of the regions coastal ecosystems and the LTER will incorporate the findings from this study into those assessments

The unprecedented drought currently in its fourth year in California, coupled with the ongoing conditions of anomalously low ocean productivity and the prospect of one the strongest El Ninos on record provide an unparalleled opportunity for researchers at the Santa Barbara Coastal Long Term Ecological Research program (SBC LTER) to test specific hypotheses pertaining to the origin, distribution, processing and bioavailability of terrestrial organic matter in coastal marine sediments and their potential for serving as a reservoir of nitrogen storage to fuel nearshore primary production during periods when nitrate concentrations are low. NSF RAPID Response award funds will be used to: (1) measure bulk properties and biomarker tracers of particulate organic matter (POM) in stream water and in coastal marine sediments at SBC sites differing in exposure to terrestrial runoff prior to and following large storm events, and (2) determine the bioavailability of dissolved organic matter (DOM) released from POM in marine sediments following large runoff events. The research will complement and inform SBC's ongoing efforts to investigate the availability and utilization of recycled forms of nitrogen in supporting the primary production of nearshore macrophytes and phytoplankton during non-upwelling periods when nitrate levels ar typically low.