Paul Koch - US grants

Geochemical, sedimentological and paleontologic evidence from deep sea sedimentary sequences indicates that significant changes in the ocean climate and chemical system occurred from the late Paleocene to early Eocene. The early Eocene climate was characterized by elevated temperatures at high latitudes and in deep oceans, by diminished thermal gradients, and by decreased atmospheric circulation. Moreover, the mean isotopic composition of marine carbonate dropped by 3 part per mil. Climate models indicate that such decreases in planetary temperature gradient must have had profound effects on continental climates. Paleocene- Eocene climate change has been proposed as an important driving force in the evolution of continental plants and animals. However, verification of model results with empirical data is difficult because of the low precision of marine-terrestrial correlations and because of a general lack of quantitative terrestrial climate proxies. This study has two goals: 1) to correlate with greater precision Paleocene through early Eocene marine strata to continental sections from the Bighorn Basin, WY, and 2) to evaluate changes in mean annual temperature and humidity in continental regions. Large scale, synchronous perturbations in the carbon isotope composition of terrestrial carbon reservoirs (organic matter, soil carbonates, and tooth apatite) and marine carbonates will supply isochrons for correlation. Temperature and humidity will be determined through oxygen isotope analysis of soil carbonates, and teeth from terrestrial and aquatic mammals.

9714263 Koch This grant provides partial support of the costs of upgrading the stable isotope ratio mass spectrometry (SIRMS) facility at the University of California, Santa Cruz. Funds will be used to purchase and develop a fluorination vacuum line for extraction of oxygen from silicate, oxide and phosphate minerals, and an induction furnace vacuum line for thermal decomposition of hydrous minerals prior to hydrogen isotopic analyses These new analytic capabilities will provide the recently hired PI, Paul Koch, with the necessary tools to conduct stable isotopic analyses of fossil bone collagen, teeth and soil carbonates as proxies in paleoecological investigations that have profound implications for understanding Cenozoic climate, habitats and regional tectonics. ***

9725854 Koch Migration patterns, dispersal, and home range are important attributes of the biology of living animals that have proven difficult to reconstruct for extinct species. Current methods, based on analogy to modern relatives, scaling relationships, or taphonomic interpretations of multiple individual sites are either controversial or they lack resolution. Migration and home range have figured prominently in ongoing debates about susceptibility to extinction, differences in speciation rates, biogeographic patterns, and patterns of co-evolution between predator and prey. Clearly, a method for determining the scale of animal movement is essential. Strontium exhibits geologically-controlled spatial variation in the isotope composition, whereas oxygen isotopes differ among regions due to climatic differences. Animals consume vegetation and drinking water and ingest the Sr and O isotope signature characteristic of their local environment. Consequently analysis of isotopic variations within and among individuals may indicate the habitat and movement patterns of individual animals. This study has three sections. First, the susceptibility of tooth enamel apatite to diagenetic alteration will be examined through analysis marine fossils deposited in sediments derived from the continent. This study will reveal if biogenic 87Sr/86Sr, phosphate (18O, and carbonate (18O values are preserved in bioapatite of progressively older fossils, and assess the rate and mechanism of alteration. This will be the first test of the isotopic fidelity of Sr in enamel, and the first attempt to examine whether known phosphate (18O values can be retrieved from ancient enamel and bone bioapatite. A second study will take advantage of the extremely low Sr isotope variability in peninsular Florida to examine home range size and migration in extinct Pleistocene proboscideans. The study will reveal if late Pleistocene proboscideans had large or small home ranges, if they undertook seasonal migrations, and if either of these attributes of range use changed between full glacial and late glacial ecosystems. Finally, it has been proposed that Paleo-Indian hunters efficiently stalked and killed entire elephant family groups. The empirical support for this conclusion, the age structure of multiple death sites, has been controversial. Large Sr or O isotopic differences among samples in enamel deposited in the last few years of life would falsify the family group's hypothesis. Overall, isotopic analysis has the potential to cast new light on old debates regarding animal movement, and it supplies a new method for detecting time or spatial averaging in a multi-individual sample.

This award provides partial support for the 6th Advanced Seminar on Paleodietary Research, to be held on the campus of the Univ. of California, Santa Cruz in September 2001.The Advanced Seminars have been the premier forum for high-level discussion
among anthropologists, geochemists, paleobiologists, and ecosystem
scientists about the ways that fossil chemistry can be used to reconstruct
the ecology, physiology, and migration patterns of humans and other
mammals. Approximately 30 seminar participants will explore the diverse
chemical approaches to hominid paleobiology. The list ranges from senior
scientists to graduate students and from archaeologists to chemists,
including speakers from 8 nations. The speakers will examine the following
general topics: 1) how biological isotope signals are influenced by the
effects of growth dynamics and post-mortem alteration, 2) how isotopes can
be used to study the scale and pattern of human mobility, 3) new isotopic
tools for studying hominid diets and habitat use, and 4) how physiology and
nutritional status are reflected in the isotope composition of fossils.
For example, several speakers will focus on the ecology and diet of
australopithecines that are several million years old, determining the
extent to which these relatives of modern humans consumed meat versus
plants. Another set of speakers will focus on the diets and food
processing technologies of modern humans over the past few thousand years.
A number of speakers will examine shifts in human migration patterns and
nutritional status, looking at the interplay between climate and cultural
change as causal agents. As has been the case with all of previous
seminars, we will publish a set of papers resulting from the presentations,
preferably as a special issue of an archaeological journal. The
publication will summarize important advances, making results available in
a centralized format to both specialists and non-specialists. If the past
is any guide, the chemical approaches to human and animal ecology,
biogeochemistry, and environmental reconstruction explored in the
publication will extend to workers in many other fields. For the
past 30 years, anthropologists and archaeologists using chemical methods
have been blazing a trail, a trail that has recently been picked up by
wildlife biologists, terrestrial paleoclimatologists and global change
researchers. The 6th Advanced Seminar on Paleodietary Research should
continue this tradition.

The Evolution of Herbivorous Marine Mammals: Ecological and Evolutionary Transitions in the Sirenia and Desmostylia
by
Paul L. Koch

In modern marine ecosystems, mammals play a minor role as primary consumers of marine plants, and the diversity of herbivorous marine mammals (e.g., sea cows) is significantly lower than that of carnivorous marine mammals (e.g, seals or whales). The diversity of marine herbivores in the past was much higher than today. What explains this disparity in the number of marine mammal herbivores between modern and ancient ecosystems? How do the ecological and physiological requirements imposed by a herbivorous diet differ from those faced by marine carnivores? Do these differences contribute to the differences in diversity between these two groups?
To answer these questions, we propose to look at the ecological and physiological transitions that occurred during the evolution of two groups - sirenians (i.e. manatees and dugongs) and a related group of hippo-sized mammals called desmostylians. We will examine animals from three time intervals. First, we will examine the ecology of the earliest sirenians and desmostylians from the Eocene (50 Ma), focusing on animals involved in the transition from terrestrial to marine systems, and correlating this change in habitat with changes in physical features, such as body size and limb morphology. Next, we plan to study the interaction of desmostylians and sirenians from the north Pacific during the Middle Miocene to assess how marine resources were partitioned between these groups, and how Pacific ecosystems were able to sustain a higher level of diversity of marine mammalian herbivores than today. Finally, our work in the Pacific will continue by looking at the lineage that gave rise to the Steller's sea cow, exploring what environmental and physiological factors facilitated the evolution of the largest marine herbivore ever.
Our study will chiefly rely on three stable isotope systems. First, carbon isotopes will be used as a proxy for diet that will allow us to discriminate between feeding in terrestrial versus marine systems. Second, variability in oxygen isotope values will be used as a proxy for the extent to which early members of each group used aquatic habitats. Mean oxygen isotope values will serve as a preliminary indicator of reliance on marine versus freshwater habitats. Finally, calcium isotopes will allow us to identify trophic level and assess whether early sirenians and desmostylians supplemented their herbivorous diet with a higher energy food resource (e.g, meat) as they overcame potential energetic barriers associated with the transition from land to sea. Together, these three systems will allow us to assess the ecological preferences of these groups, and better understand the factors involved in the evolution of marine herbivores.

Putting Human Exploitation of Marine Resources in Temporal and Environmental Context
By
Paul L. Koch
Diane Gifford-Gonzalez


Widespread evidence exists for intensified resource use by humans in coastal California over the past several thousand years. This includes a shift from inland foraging in the early Holocene to use of marine shellfish, fish, mammals in the middle Holocene. Around 1000 B.P., human foraging changed again, shifting away from reliance on coastal resources to those of the interior. Around the same time, the northern fur seal, formerly common in central and northern California, disappeared from central California archaeological sites, never to reappear in aboriginal sites.
These changes in settlement and subsistence have been interpreted by some as the result of resource depression caused by growing human populations. In contrast, researchers working in the Santa Barbara region, where there is a well developed record of Holocene variations in rainfall, ocean temperature, and upwelling intensity, contend that the late Holocene shift was climatically driven. This argument is part of a broader debate that links changes in human ecology in the southwestern U.S. to the Medieval Climatic Anomaly. This argument has recently been extended to explain human and marine mammal shifts in central California, but little paleoclimatic data at high-temporal resolution exist for this region, or for the region farther north, where northern fur seals were harvested into historic times.
The timing of the earlier shift to intensified use of coastal resources in the middle Holocene (6000 B.P.) is intriguing as well. Elsewhere on the globe, evidence is mounting for a shift in ocean circulation and global climate at this time, perhaps relating to the onset of modern El Nino/La Nina climatic cycles. At present, well-constrained paleoenvironmental data from the central and northern California coast are lacking. Thus it is impossible to determine if changes in human settlement and resource use are the result of climatic forcing.
In our multidisciplinary project, we will use direct 14C AMS dates of archaeological materials to construct a finely-textured temporal framework for the study of cultural, paleoecologic, and paleoclimatic changes on the central and northern California coast. We have several goals. Chemical and isotopic variations in mollusk shells will be a key source of information on past ocean conditions. Likewise, isotopic variations in marine mammals can reveal migration patterns and trophic dynamics, and how they changed with inferred changes in climate. As a consequence, we will focus our dating efforts on these materials.
We anticipate the following results: 1) construction of a time series of mollusk shells from both central and northern California that will form the basis of future paleoclimatic research, 2) an assessment of whether or not stratigraphic relations at a number of California archaeological sites are reliable, or if they have been perturbed by animals burrowing and churning, and 3) precise information on the timing of changes in the marine mammal fauna and human communities in both regions. Detailed isotopic and faunal analyses will be conducted once we've established a robust chronologic framework.

There is considerable debate as to when the Sierra Nevada developed as a significant topographic feature and how it affected the past climate of this region. One view holds that the Sierra Nevada is a young mountain range, with net surface uplift of some 2km in the last 10 million years. In contrast, recent work suggests that the Sierra Nevada has been a long-standing topographic feature. Previous analysis of the hydrogen and oxygen isotope composition of smectite produced by the weathering of volcanic ashes from sections along the east side of the Sierra Nevada shows that, in the central Basin and Range, the oxygen isotopes of smectite increased slightly in the last 16 million years. This result contrasts with that of one section in the southern Basin and Range, which shows a large increase in oxygen isotopes from 14 to 6 million years. These results indicate that the Sierra Nevada has been a long-standing topographic feature at least for the past 16 million years. Moreover, if these isotopic shifts result solely from topographic change, then the Sierra has a spatially varying topographic history, with some 700 m of topographic loss in the northern Sierra and ~2000m of lowering of the southern Sierra in the Late Cenozoic. The data can also be explained by a strengthening of the summer monsoon in the Late Cenozoic that could result in isotopically heavier precipitation, particularly in the southern areas of the Basin and Range.

This study is testing the hypothesis that the Sierra Nevada had a spatial varying topographic history by: 1) collecting isotopic data from the southern Basin and Range in order to separate topographic from climatic effects; 2) constructing a regional isotopic map of the Basin and Range to enhance understanding of the regional topographic and climactic history of this region; 3) sampling over a larger time range to determine what isotopic changes have occurred both in rocks younger than 2 million years and older than 16 million years; and 4) collecting isotopic data from other substrates, particularly fossil mammals, to reduce the uncertainty associated with any one isotopic proxy for paleoprecipitation.

0421510
Ravelo
This Major Research Instrumentation award to University of California Santa Cruz provides funds to establish a cutting-edge stable isotope analytical facility for environmental research. It includes support for the acquisition of three new mass spectrometers plus new front-end systems for sample preparation and separation, and adds capabilities for undertaking natural abundance, isotopically-enriched and compound specific analyses of organic material to the existing two systems that will continue to serve requirements for mineral-phase analyses. The broader impacts of the acquisition include a strong commitment to involve students, researchers and visitors at many levels in research undertaken at the facility. In addition, the instrumentation will be managed as a regional shared-use facility, open to researchers from throughout UCSC and outside, and it will be used to study a wide array of projects with compelling societal relevance (e.g. climate change, pollution). UCSC is providing 30% of the project cost from non-federal funds. This proposal is supported by the Division of Ocean Sciences at NSF.
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This is a collaborative proposal by Principal Investigators at the University of California-Los Angles and Santa Cruz, University of Alaska-Fairbanks, and the Smithsonian Institution. This award will be supported with funds from the Population Ecology Program in the Division of Biology and Arctic Natural Sciences Program. The effects of future climatic change on arctic species are a source of great uncertainty and concern and the Arctic has experienced large changes in climate since the last glacial cycle. Therefore, the study of biotic responses to the previous perturbations may provide important evidence of how the genetic diversity, diet, and geographic range of arctic species will be altered by future global climate change. Using DNA analysis, the Principal Investigators will examine the history of genetic diversity in the barren-ground caribou and an extinct arctic horse based on samples from three localities in Beringia. Bones recovered from the permafrost are an excellent source of ancient DNA and can be 14C dated. Two recent genetic studies analyzed DNA sequences from brown bear bones entombed in the arctic permafrost and found evidence of three distinct genetic epochs over the past 40,000 years, each marked by population turnover events. These previously unrecognized epochs are defined by DNA sequences from specimens older than 35 thousand (ka) BP, from specimens 21 to 10 ka BP, and by sequences from modern populations. Paleoclimate studies provide evidence that population turnover between these periods may be explained by changing climate relating to the mid-Wisconsin interstadial, the last glacial maximum, and the Holocene. However, paleoenvironmental data are sparse and inconclusive and these genetic patterns have not been verified in other species. As herbivores, caribou, and horses represent a different trophic level from brown bears and both species specialize on consuming different types of vegetation (tundra and grass-steppe, respectively). The Principal Investigators predict that ecosystem-wide climate change unfavorable to large herbivores and their predators would result in synchronous cycles of population turnover in both species across all three localities. These changes should match those previously observed in the brown bear and gray wolf. Similar regional or local ecosystem change would be manifest as synchronous cycles in a subset of localities. In contrast, differing patterns of genetic change in the two species would imply a change in the tundra/forest dominance or the presence of new species-specific competitors and/or predators. In either case, the study will provide important evidence of the potential role of climate change on genetic diversity in arctic mammals.

The Principal Investigators will identify specific agents of environmental change and reconstruct past arctic environments through study of three independent classes of environmental surrogates in all three locations. First, they will develop stable isotope profiles for the remains analyzed in the DNA study. These profiles will serve as proxies for regional climate change and allow changing animal diets to be inferred. Second, they will use plant material imbedded in the teeth of herbivores to reconstruct the changes in local flora utilized by the two herbivores. Third, they will utilize existing pollen records and other paleoenvironmental data to reconstruct the regional vegetation and general climate during periods of observed genetic turnover. Importantly, they will 14C date 300 bones from the two herbivore species across Beringia which will place their results in a temporal context that will allow integration with existing climate data.

Boarder Impact: All data will be placed in the public domain for future studies as new
techniques and questions arise. Additionally, this research will train a group of students in cutting-edge, interdisciplinary research that incorporates genetics, pollen analysis, high-resolution radiocarbon dating, and stable isotope ecology.

Under this award the PIs will perform an integrated data-modeling study of Holocene oceanographic changes along the NE Pacific margin to understand the impact of Holocene climatic and oceanographic changes on marine and terrestrial communities (including human populations) along the NE Pacific Margin. The paleoenvironmental data will come from oxygen isotope, minor element, and 14C analyses of dated mollusk shells from archaeological sites in central California and British Columbia. Most of these shells have already been individually dated via 14C analysis as part of a project supported by NSF Geology & Paleontology. By coupling these three biogeochemical tracers, and examining both bulk samples (which integrate several years of growth) and intraskeletal growth series (which provide weekly-to-monthly temporal resolution), the PIs can reconstruct millennial, inter-annual, and seasonal variability in ocean temperature, upwelling intensity, and freshwater flux to the coastal zone. Through studies of extant mollusks, the PIs will develop species-specific isotope and minor element calibrations and assess the levels of variance inherent to nearshore species. To place the data in broader context, the PIs will use globaland regional-scale coupled atmosphere-ocean models to study the impact of changes in climate forcing on ocean currents, surface temperature, upwelling, and precipitation on a variety of time scales. Comparison of model results with proxy data will permit model performance, and may reveal key gaps in the proxy record. In addition to gaining insight into the factors driving climatic and oceanographic change along the NE Pacific margin, the PIs will use our climate data to test hypotheses for Holocene anthropological and paleoecological transitions.

The Paleoecology of Pinnipeds on the Pacific Rim
Intellectual Merits - Recent studies have shown that humans, including prehistoric people, play a major role in shaping the ecosystems they inhabit, and that some of the ecosystems we are familiar with today operated differently in the recent past. Historical and paleoecological data provide crucial contextual information for the conservation communities considering future management decisions, especially for species that have witnessed relatively recent population declines. Our overarching goal is to explore how environmental and anthropogenic factors interacted to generate ecological shifts on the northeastern Pacific coast over the past 5000 years. The most complete record of these changes is found in coastal archaeological sites, where the faunas of past terrestrial and marine ecosystems can be studied to investigate paleoecologic shifts. Furthermore, the recognition of major ecological shifts will be important for archaeologists attempting to decipher changes in human demography and resource utilization. In past studies, northern fur seals were studied using isotopic and archaeological data to show that the species has changed its breeding and migratory behavior over the past 1000 years. Fur seal bones were also dated to show that the collapse of local breeding colonies was not synchronous across the Pacific margin. For this study, we will investigate changes in foraging, migratory, weaning, and haul-out behavior in four different pinniped species since the mid-Holocene through construction of time series on isotopic composition, presence/absence, relative abundance, and age/sex distribution. In addition, we will develop two new methods to assess weaning age in pinnipeds. The first will use growth structures in pinniped teeth as proxies for weaning age and maternal investment. The other is a biogeochemical approach that uses changes in the N isotope ratios in bone growth series and tooth dentin. We will focus on four centers of pinniped diversity - the eastern Aleutian Islands, the US-Canadian border, the Oregon coast, and the Channel Islands. This project will include an extensive literature search and compilation of existing faunal information into a database on Holocene pinniped dynamics along the NE Pacific margin.

Broader Impacts - This study will show how insights into the ecology of threatened species may be gleaned from archaeological data. This is important for species in relict populations, whose current ecology may be shaped by recent exploitation or environmental change. Three of the four species we will study are presently undergoing rapid population declines, but the causes for these declines are far from clear. This study will provide baseline data on the ecology of these species over deep time, and indicate whether or not they experienced similar declines in the past in relation to anthropogenic or environmental perturbations. We will work with conservation biologists to make our data available to those making management decisions. To this end, in winter 2004 we will co-host a conference, funded by the UC-PACRIM, which will bring together archaeologists, historians, marine mammal ecologists, conservation biologists, and social scientists. Our goal is to evaluate the archaeological and historical record of NE Pacific pinnipeds in the context of the ecology of these species today, and then to develop strategies for integrating this information into decision-making processes of conservation policy makers. A more immediate impact of this project will be the education of graduate and undergraduate students at UCSC. In addition, our prehistoric approach to marine mammal ecology was developed into a module for COSMOS (California State Summer School for Mathematics and Science) in 2002 and 2003. A diverse group of students (grades 8-12) took part in a 4-week course that integrated field, laboratory, and classroom exercises designed to introduce scholarly and motivated young people to science.

During previous NSF-sponsored research, the PI's discovered that southern elephant seal colonies once existed along the Victoria Land coast (VLC) of Antarctica, a region where they are no longer observed. Molted seal skin and hair occur along 300 km of coastline, more than 1000 km from any extant colony. The last record of a seal at a former colony site is at ~A.D. 1600. Because abandonment occurred prior to subantarctic sealing, disappearance of the VLC colony probably was due to environmental factors, possibly cooling and encroachment of land-fast, perennial sea ice that made access to haul-out sites difficult. The record of seal inhabitation along the VLC, therefore, has potential as a proxy for climate change. Elephant seals are a predominantly subantarctic species with circumpolar distribution. Genetic studies have revealed significant differentiation among populations, particularly with regard to that at Macquarie I., which is the extant population nearest to the abandoned VLC colony. Not only is the Macquarie population unique genetically, but it is has undergone unexplained decline of 2%/yr over the last 50 years3. In a pilot study, genetic analyses showed a close relationship between the VLC seals and those at Macquarie I. An understanding of the relationship between the two populations, as well as of the environmental pressures that led to the demise of the VLC colonies, will provide a better understanding of present-day population genetic structure, the effect of environmental change on seal populations, and possibly the reasons underlying the modern decline at Macquarie Island.
This project addresses several key research problems: (1) Why did elephant seals colonize and then abandon the VLC? (2) What does the elephant seal record reveal about Holocene climate change and sea-ice conditions? (3) What were the foraging strategies of the seals and did these strategies change over time as climate varied? (4) How does the genetic structure of the VLC seals relate to extant populations? (5) How did genetic diversity change over time and with colony decline? (6) Using ancient samples to estimate mtDNA mutation rates, what can be learned about VLC population dynamics over time? (7) What was the ecological relationship between elephant seals and Adelie penguins that occupied the same sites, but apparently at different times? The proposed work includes the professional training of young researchers and incorporation of data into graduate and undergraduate courses.

ABSTRACT

PI will recover important geochronological and paleoenvironmental information for a
suite of ~50 Paleocene vertebrate fossil localities in the Nanxiong Basin of south China that are rapidly being destroyed due to high rates of agricultural and urban development. Given the accelerating development in this part of south China and the imminent retirement of the scientists who originally discovered these fossil localities, this proposal meets a key criterion for SGER funding - it has a severe urgency with regard to availability of, or access to data, facilities or specialized equipment. Magnetostratigraphic and chemostratigraphic methods will be applied to Paleocene deposits in the Nanxiong Basin to answer two fundamental questions. (1) Do the major biotic turnovers that mark the boundaries between Paleocene Asian land mammal ages coincide in time with the
major turnovers that mark the boundaries between Paleocene North American land mammal ages? (2) Do the Paleocene Asian land mammal age boundaries correlate to episodes of regional or global environmental change? This project will strengthen international collaborations between Chinese and American paleontologists, which is particularly important given the excellent vertebrate fossil records on each continent and the biogeographic connections that Asia and North America have shared during the Mesozoic and Cenozoic.

Understanding Reptile Paleoecology: A Stable Isotope Approach

Paul L. Koch, Univ. of California, Santa Cruz

Today most crocodilians (crocodiles, alligators, gavials, and their kin) live in fresh to brackish water. Only a few crocodilians are able to tolerate marine water using special salt-excreting glands to maintain osmotic balance. Yet, the geographic distribution of crocodilians indicates that some groups crossed major ocean basins in their evolutionary history, leading some workers to conclude that they may have been more tolerant of salt water in the past. Paleontologists have tried to identify trends in morphology or relationships that would illuminate the origin and evolution of salt-water tolerance in crocodilians, but these studies have been largely inconclusive. Isotopic methods offer powerful tools for exploring the diet, habitat preferences, and physiology of modern and fossil animals. We will study the origin and evolution of salt-water tolerance in crocodilians using naturally occurring variations in stable isotopes. We will use carbon and strontium isotope variations to monitor the habitat in which crocodilians were feeding, and oxygen isotope variations to determine whether they were drinking fresh or marine water.
Reptiles have not been studied extensively using isotopic methods. Therefore, we will take a close look at modern crocodilians to ensure that our studies of ancient crocodilians are on a solid foundation. First we will study captive crocodilians in Florida. In this controlled setting, we can measure the stable isotope composition of all the water and food ingested by the animal. This will let us determine the contribution of each source to the tooth enamel of a crocodilian. We will then study wild crocodilians at a coastal wildlife refuge in Louisiana. Here we will measure the isotopic composition of crocodilians and their prey to better understand how much "noise" is introduced by a natural environment. These two modern experiments will inform our study of ancient crocodilians, and serve as a basis for other workers using isotopes to study modern and fossil reptiles. Finally, we will use these isotopic methods to assess the salt-water tolerance and adaptations of different fossil crocodilians. In most cases, these fossils come from coastal settings, so they may potentially have used saline habitats. We will analyze fossil species that are classified near the origins of the major groups of living crocodilians. This approach will shed light on the ecology of these groups as they began to diversify and radiate. Our ultimate goal is to determine if the crocodilians are a primitively salt-water group that has become more restricted to freshwater, or a primitively fresh-water group with a few derived groups that tolerate salt water.

0824978
Zachos


This proposal seeks funding for a new gas source dual-inlet isotope ratio mass spectrometer with a Kiel carbonate device. Requested is a Thermo MAT 253 with a Kiel IV prep device. The system will be capable of routine carbon and oxygen isotope analyses from carbonates with high precision and low sample size (~5 µg C). The acquisition will allow the use of individual acid reaction vessels, increasing precision and minimizing sample sizes. The instrument will add to existing analysis capability. General research themes outlined for the new instrumentation fall into the areas of paleoclimatology, paleoceanography and paleoecology. One focus is understanding the biogeochemistry and climate evolution of the late Cretaceous and early Cenozoic ?greenhouse? worlds; the causes and evolution of the Paleocene-Eocene Thermal Maximum (PETM). The PI intends to measure shell carbonates spanning the PETM in the fossil record. Shell analysis obviates artifacts due to sediment reworking or bioturbation, but requires low sample volumes. A related project will look at the coupling of biogeochemical cycling, including nutrients, and climatic forcings during the PETM. The instrument will also be applied to understanding paleoclimatic and paleoenvironmental forcings on the ecology, evolution of extant and ancient vertebrates (extinct). In addition, foraminiferal isotope analysis will be used to reconstruct paleoclimates associated with the Last Glacial Maximum (LGM). Aside from the PI and co-PI research thrusts, a number of other PIs at UCSC and elsewhere will be supported. The management plan has the new instrument replacing an Optima (which will be retired). No additional laboratory space will thus been needed. A lead technician and lab manager is currently employed and partial support is requested in Year 1. Zachos will oversee the installation and initial management of the Kiel IV device. It is expected that grant support and per-sample fees will support the facility long-term. The UCSC Stable Isotope Laboratory operates on an open access policy. This helps attract users from UCSC, other regional institutions and the international scientific community. Users have been roughly ~50% female. Recharge rates are kept low and the laboratory manager provides extensive training. UC-wide programs such as the California Alliance for Minority Participation ensures a diverse in-house user base.

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

This collaborative research project is being undertaken by Dr. Nathaniel J. Dominy, University of California Santa Cruz, and Dr. Salima Ikram, American University of Cairo, Egypt, to analyze isotope ratios of mummified baboons and to compare them with modern baboon populations in an attempt to identify the location of the lost city of Punt.

Punt was a celebrated destination in Ancient Egypt. It was an exporter of valued commodities such as ebony, myrrh, electrum, and exotic pets (leopards and baboons). The historical importance of the Egypt-Punt relationship is twofold. First, it is one of the earliest examples of peaceful trade between neighboring political states. Second, it is one of the longest commercial alliances in human history, spanning more than 1200 years. Yet the location of Punt is a mystery. Scholarly debate over the past century has resulted in five hypothetical regions: (1) Eritrea-Ethiopia; (2) the Sinai Peninsula; (3) Somalia; (4) western Uganda, and (5) Yemen. The collaboration will test among these competing geographic hypotheses by measuring ratios of carbon, nitrogen, and oxygen stable isotopes in the hair and bone tissues of mummified baboons, which were likely imported from Punt. The distinctive combination of these values is expected to match those of a modern baboon population inhabiting one of the five hypothetical locations above. This cross-disciplinary project represents a unique bridge between Geology (Geochemistry) and three sub-disciplines in Anthropology (Archaeology, Egyptology, and Primatology). The results are expected to complement and inform ongoing debates concerned with Egyptian history and foreign trade.

The broader impact of this project lies in its geographic scope and the integration of new and emergent technologies to address a central question in human history. Empirically, the PIs expect to identify the location of Punt. Theoretically, the research will advance our understanding of how human commerce and foreign policy evolved. Practically, the PI intends to enhance the education and laboratory training of 2 graduate students. The project will also permit greater intellectual exchange across academic disciplines and international borders.

From the middle Mesozoic (approximately million year ago) to the present, the topography of the western Cordillera of North America evolved in response to a diverse history of uplift, exhumation, and down-drop, due in part to first convergence and then transform motion along the western margin of North America. This time interval also saw many dramatic changes in global climate, including the transition from a Mesozoic-Paleogene greenhouse to a Neogene world with ice on the poles. The role of climate change in the tectonic evolution of the western Cordillera has been much discussed, as has the influence of topography on paleoclimate. In this project, two cutting-edge techniques from stable isotope geochemistry will be used to determine past temperatures and paleohydrology, which will allow reconstruction of past elevations across the northern Basin and Range Province. Variations in past temperature and hydrology will be mapped during three key time intervals - the warm Late Cretaceous (approximately 70 million years ago) and Early Eocene (approximately 55 million years ago), and the relatively cool Late Miocene (approximately 10 million years ago). By mapping isotopic variations at different time slices, past elevations at interior sites can be estimated while controlling for the effects of global climate change on geochemical records. This approach will address outstanding questions about the tectonic history of western North America, such as: Was there a very high plateau in western Nevada in the Late Cretaceous, analogous to the current South American Altiplano? Was the region east of the Sierra Nevada Mountains at low or high elevation during the Eocene? The answer should be clear in temperature and isotope hydrology profiles across the region.

Elevation is a fundamental parameter in tectonics. Reconstructing past elevation is therefore critical for testing geodynamic models that have been proposed to explain the tectonic evolution of the western Cordillera. In addition to constraints on the tectonic evolution of the western U.S., this study will add to the growing body of continental paleoenvironmental data that are critical for comparison to output from computer climate simulations. As new simulations are developed at finer spatial scales, it is essential to have paleoclimatic data at a similar scale, particularly in regions with great topographic relief.

Paul Koch
The University of California-Santa Cruz
The Paleoecology and Evolution of White Sharks: An Isotopic Study

This is a study of modern and ancient shark ecology using stable isotope analysis, which permits the quantification of patterns and processes in ecological systems. While isotope systematics have not been studied extensively in sharks, based on the wide utility of isotopic methods in studies of the ecology and paleoecology of other vertebrates, we hope that our approach will broaden our understanding of shark ecology. To lay the foundation for both modern and paleontological research, we will analyze samples from a recently concluded controlled feeding study, which also included calcified structures. The interpretative framework set by our feeding study will allow us to assess the dietary and habitat preferences of modern white sharks off the California coast. We will sub-sample annual growth bands in the vertebrae of white sharks collected from the mid-to-late 20th century. Our study should reveal growth and seasonal shifts within an individual?s lifetime, as well as possible ecological changes associated with the increase in the marine mammal populations since the 1970s.

Our project featuring modern and ancient white sharks will contribute to critical ecological questions, which are difficult to answer with other tools. Our past work have had practical impacts for our understanding of the ecology and conservation biology of modern species. This work has brought a new set of tools to modern ecology and it can offer an essential historical context for the study of modern ecosystems. This project will contribute to the education of UCSC graduate and undergraduate students. It will support the mentoring of a post-doctoral researcher. It will train a Ph.D. student. We expect undergraduate students to develop senior thesis projects around this study. We will explore developing a new course on historical marine ecology, using information from this proposal and prior studies of seals, condors, and other taxa. Our results will also contribute to a new fossil shark website associated with the Florida Natural History Museums Ichthyology Department. These outreach venues will allow educators, youth, and the general public to explore ancient and modern shark ecology.

Building on previously funded NSF research, the use of paleobiological and paleogenetic data from mummified elephant seal carcasses found along the Dry Valleys and Victoria Land Coast in areas that today are too cold to support seal colonies (Mirougina leonina; southern elephant seals; SES) supports the former existence of these seals in this region. The occurrence and then subsequent disappearance of these SES colonies is consistent with major shifts in the Holocene climate to much colder conditions at the last ~1000 years BCE).

Further analysis of the preserved remains of three other abundant pinnipeds ? crabeater (Lobodon carciophagus), Weddell (Leptonychotes weddelli) and leopard (Hydrurga leptonyx) will be studied to track changes in their population size (revealed by DNA analysis) and their diet (studied via stable isotope analysis). Combined with known differences in life history, preferred ice habitat and ecosystem sensitivity among these species, this paleoclimate proxy data will be used to assess their exposure and sensitivity to climate change in the Ross Sea region during the past ~1-2,000 years

Anthropogenic and natural climatic perturbations drive changes in population dynamics of species, the structure and function of food webs, and biogeochemical processes. The PIs propose a comparative analysis of three major ecosystems to investigate temporal change in the structure of mesopelagic food webs.

Intellectual Merit: The PIs will investigate temporal changes in the structure of mesopelagic food webs in three major ecosystems: the California Current, Eastern Tropical Pacific, and the Peru-Humboldt Current over the past 50 years using a globally distributed apex predator as an indicator species. The predator is the sperm whale, Physeter macrocephalus, and the PIs will use stable isotope ratios of carbon and nitrogen as indicators of habitat and diet. Isotope values from bulk tissues of teeth and skin (C and N) as well as specific amino acids (N) will be used to address two primary objectives: (a) examine temporal patterns in the trophic position of sperm whales (as an indicator of changes in mesopelagic trophic structure) and baseline isotopic values (as indicators of nutrient cycling); and (b) use isotopic values, which vary among systems, to define the population structure of sperm whales from past and present times, and connectivity among populations.

Broader Impacts: This project will be conducted by researchers from academia and NOAA/NMFS with expertise in stable isotope analysis, trophic ecology, and ecosystem-based management of protected species. As such, it represents an opportunity for collaboration between scientists with complementary skills and from diverse institutions to compare structure and function of ecosystems across the eastern Pacific. Moreover, it represents a collaboration between academia and a federal agency with research and management responsibilities. The project will support a postdoctoral scholar (Iliana Ruiz-Cooley), a Ph.D. student, and undergraduate students to enhance their career and collaborative opportunities. The PIs anticipate that the results of their study will provide unique data to evaluate the effects of perturbations within and among mesopelagic ecosystems. This information may allow the scientific community to relate trends in climate to changes in trophic position of top predators and nutrient cycling, allowing more robust understanding of possible responses to future warming. Finally, as the first systematic applications of compound-specific stable isotope analysis to marine mammals, the project should be highly instructive for future evaluations of the feeding ecology, population structure and dynamics of endangered marine mammals. As such, this novel approach and unique historic perspective will be directly applicable for stock assessment and management.

Coyotes are flourishing and expanding their range in North America. In coastal settings, it is possible that marine foods, such as seals or salmon, may be fueling their success. This project will explore the extent to which these types of foods are used by coyotes along the central coast of California, and how growing populations of coyotes impact other predators and their prey. To assess whether these types of effects are recent and perhaps facilitated by human activity or historical, samples from the same area thousands of years ago will be compared with recently-collected materials. Samples collected along transects that start at the ocean?s edge and penetrate kilometers inland will be tested in a variety of ways, including analyses of stable isotopes and genetic material. Data thus far suggest that marine foods are indeed important to modern coyotes, but not to coyotes living in the same area 2000 years ago. If this pattern holds, it would suggest that use of marine resources by contemporary coyotes is a new behavior.

A longer perspective on resource use by coyotes may have important implications for understanding and managing the ecological impacts of modern coyotes, especially in areas where they receive marine and other types of "extra" food, including food inadvertently provided by humans -- garbage and road kill, for example. Undergraduate students will be involved in the research, gaining valuable field and laboratory skills and being mentored in career development so that they can help solve environmental problems of the future. In addition, results of this research will be made available to the public through presentations at state parks where the research takes place, as well as through visits to local schools.

This award funds the acquisition of a new Thermal Ionization Mass Spectrometer (TIMS) to be integrated into the W.M. Keck Isotope Laboratory at the University of California, Santa Cruz. The TIMS will be co-located within the recently renovated climate-controlled laboratory and wet chemistry clean labs needed for the preparation of geologic samples for isotopic analysis. The reopening of this open-user facility will catalyze new research and provide the tools needed to train undergraduate, graduate and postdoctoral researchers in the use of high precision isotopic methodologies. The Earth and Planetary Science department, which is one of the largest Earth Science department?s in the country with over a 150 majors, has a population representative of the student body which includes over 40% from underrepresented ethnic backgrounds and a first year class made up of 41% of first generation college students. Outreach from this award includes a mini-grants program, available to internal and external users, to support exploratory and developmental research.

This facility will allow high precision U-Pb and U-series geochronologic dating with research applied to the origin and evolution of the continental and oceanic crust, the dynamics of volcanic systems and the timing and rate of glaciations and climatic change. Additional capabilities include measurements of the Sr, Ca, Nd, and Pb isotope systems, which are applied by UCSC Earth and Marine scientists to reconstruct variations in paleo-seawater in response to changes in tectonic uplift, climate, biogeochemical cycling and ocean circulation. UCSC paleontologists and ecologists use these same tools to study food web dynamics and foraging ranges of organisms in the present and past.

Stable isotope analysis is now one of the most important tools in a remarkable variety of research, with key applications spanning oceanography, biogeochemical cycle research, ecology and food webs, paleoecology, archaeology, and paleoclimatogy. Work in all these areas increasingly requires sensitive analysis of the isotope ratios of a range of elements (carbon, hydrogen, oxygen, nitrogen, sulfur), in a wide variety of sample types, and the most innovative projects increasingly require new, leading-edge approaches, such as isotopic analysis of individual organic compounds (CSIA). This award to the University of California at Santa Cruz (UCSC) involves the acquisition of an isotope-ratio-monitoring mass spectrometer (IRMS) to serve investigators and students across multiple disciplines. This acquisition will have wide broader impacts. First, the instrumentation will significantly expand UCSC's basic research infrastructure, supporting core campus priority areas for excellence in coastal sciences and environmental sustainability research. It strongly enhances UCSC's core education and teaching mission, allowing graduate and post-doc training on cutting-edge instrumentation while supporting a far greater range of projects. The instrumentation will support undergraduate research, via senior theses and direct involvement in research labs, as well as the incorporation of hands-on projects into higher level courses. The project team will also develop a new initiative for a summer outreach program, in collaboration with UCSC's division of student success.

UCSC will acquire a Thermo Scientific 253+ isotope ratio mass spectrometer (IRMS), with two front-end peripherals configured for cutting-edge CSIA capabilities, including the ability to make isotopic measurements on unknown compounds, and the addition of sulfur isotope capability. This high-sensitivity IRMS will have two main sample input peripherals: (1) a GC-Trace Ultra-GC coupled to a TSQ Duo Triple Quadrapole Mass Spectrometer, and configured with a programmable Tri-Plus RSH auto-sampler capable of automated derivatization/standard additions; and (2) an IsoLink CNOHS Elemental Analyzer (EA) with a new unified combustion/pyrolysis design that will bring needed sulfur isotope capability. Each component in this configuration was chosen to fulfill a critical need. The 10 KV 253 IRMS will provide high sensitivity, allowing a range of new, nano-scale compound-specific applications, particularly critical for individual-compound N measurements. The customized Tri-Plus RHS auto-sampler can both make and inject derivatives with automated addition of internal standards. This will provide high sample throughput. The TSQ Duo Triple Quadrapole Mass Spectrometer represents a completely novel, cutting-edge capability, allowing researchers to simultaneously identify unknown structures as they measure their C and N isotope ratios. Finally, the EA IsoLink (CNSOH) interface will bring the ability to measure S isotopes to UCSC for the first time, allowing 13C, 15N, and 34S values to be measured simultaneously on a single sample, even at extremely high C/S ratios (e.g., wood samples).

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.