Current Projects   

As Collection Manager of the microfossil collection at UCMP, my primary task is to organize and database a century's accumulation of slides, samples, documents, and literature so that this wealth of information can be readily accessed for research and teaching at the museum and via the internet. There are hundreds of thousands of slides containing millions (billions?) of specimens awaiting my attention. Hopefully, my eyesight and sanity will last long enough to fulfill a significant part of this mission before my own fossilization ensues! You can visit the now rapidly expanding microfossil database and learn more about these and considerably larger fossils at the UCMP website.

As Museum Scientist, my research interests are in the field of micropaleontology, particularly Foraminifera and Ostracoda. I am currently involved in projects on the Tertiary of Chile (see those completed in Selected Publications) and Recent of California. The latter study has been a long-term environmental study and is described below.


LAKE MERRITT

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Several years after Samuel Merritt dammed this former tidal slough in 1869 and began developing its surrounding wetland, flaws in his "Jewel of Oakland" became unpleasantly evident as silt and algae accumulated. Although part of it was designated as the nation's first wildlife refuge (protecting more than 90 species of migrating waterfowl), Lake Merritt also serves as a drainage basin for the regional flood control system, receiving urban runoff from a 4,650 acre watershed through 60 storm drain outfalls. Four culverted creeks drain into this 145-acre lagoon from the east, while tidegates regulate flow through a narrow channel connecting it with Oakland Inner Harbor and San Francisco Bay. The lagoon is also polluted by illegal dumping of substances toxic to marine life, such as paints, solvents, and oil. In addition to mechanical harvesting of its widgeon grass, 1,000 to 7,000 pounds of trash are removed from Lake Merritt every month.

Anticipating remediation efforts by the City of Oakland, Jere Lipps and I realized there was an opportunity here to study before and after effects on the microfauna. Several other studies have revealed foraminiferal responses to pollutants, suggesting their utility as environmental monitors. I have recognized 27 species of Foraminifera, whereas the late Dawn Peterson had identified 22 species of Ostracoda. About half of each group comprises species that are inhabitants of the lagoon; the rest are normal marine foraminifers tidal-transported from San Francisco Bay, and freshwater ostracodes imported by drainage from the Oakland watershed. The more common species (shown below) are typical inhabitants of hyposaline waters. Histologic staining reveals that the majority of our assemblages from depths below one meter were devoid of living specimens when collected. Most of the living specimens were recovered from water depths less than a meter in the tidal inlet and along the margins of the lagoon where and there are visible signs of life, such as algae and mussels. Data obtained with a YSI 85DŽ water monitoring probe confirms that stratification of the water column results in an unmixed deeper layer characterized by low levels of dissolved oxygen. The decay of organics on the bottom of the lagoon depletes the oxygen and releases hydrogen sulfide that bubbles to the surface, and which is evident in the unpleasant odor and dark color of the mud samples. We suspect most of the deeper assemblages were created by post-mortem transport from the shallow margins, but we cannot rule out the possibility of intermittent mass mortalities when dissolved oxygen levels drop below a tolerable threshold.

Unlike foraminiferal assemblages in the bay, those in Lake Merritt often include malformed specimens, but surprisingly in lower relative abundance than typically reported from stressed environments where they have been linked to high levels of contaminants, heavy metals, industrial pollution, and domestic sewage.

Views of Lake Merritt


Lake View 1

Lake View 2

Lake View 3

Jere sampling

Dawn sampling

Tidal inlet

Surface oil film

Visitor

Microfauna from Lake Merritt




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