@article {2567,
	title = {Implications for chloro- and pheopigment synthesis and preservation from combined compound-specific δ13C, δ15N, and Δ14C analysis},
	journal = {Biogeosciences},
	volume = {7},
	year = {2010},
	month = {Jan-01-2010},
	pages = {4105 - 4118},
	abstract = {Chloropigments and their derivative pheopigments preserved in sediments can directly be linked to photosynthesis. Their carbon and nitrogen stable isotopic compositions have been shown to be a good recorder of recent and past surface ocean environmental conditions tracing the carbon and nitrogen sources and dominant assimilation processes of the phytoplanktonic community. In this study we report results from combined compound-specific radiocarbon and stable carbon and nitrogen isotope analysis to examine the time-scales of synthesis and fate of chlorophyll-a and its degradation products pheophytin-a, pyropheophytin-a, and 132,173-cyclopheophorbide-a-enol until burial in Black Sea core-top sediments. The pigments are mainly of marine phytoplanktonic origin as implied by their stable isotopic compositions. Pigment delta15N values indicate nitrate as the major uptake substrate but 15N-depletion towards the open marine setting indicates either contribution from N2-fixation or direct uptake of ammonium from deeper waters. Radiocarbon concentrations translate into minimum and maximum pigment ages of approximately 40 to 1200 years. This implies that protective mechanisms against decomposition such as association with minerals, storage in deltaic anoxic environments, or eutrophication-induced hypoxia and light limitation are much more efficient than previously thought. Moreover, seasonal variations of nutrient source, growth period, and habitat and their associated isotopic variability are likely at least as strong as long-term trends. Combined triple isotope analysis of sedimentary chlorophyll and its primary derivatives is a powerful tool to delineate biogeochemical and diagenetic processes in the surface water and sediments, and to assess their precise time-scales. 

},
	doi = {10.5194/bg-7-4105-201010.5194/bg-7-4105-2010-supplement},
	url = {http://www.biogeosciences.net/7/4105/2010},
	author = {Kusch, S. and Kashiyama, Y. and Ogawa, N. O. and Altabet, M. and Butzin, M. and Friedrich, J. and Ohkouchi, N. and Mollenhauer, G.}
}
@conference {1636,
	title = {The formation history of Long Island Sound},
	booktitle = {Long Island Sound Research Conference},
	year = {2006},
	note = {id: 1187},
	month = {2006},
	address = {Groton, CT},
	author = {Varekamp, J. C. and Thomas, E. and Lewis, R. and Altabet, M.}
}
@conference {892,
	title = {Nitrogen isotopic ratio records the eutrophication history of Long Island sound},
	booktitle = {American Geophyscial Union, Joint Assembly},
	volume = {85},
	year = {2004},
	note = {id: 732},
	month = {2004},
	publisher = { 	American Geophysical Union (AGU)},
	organization = { 	American Geophysical Union (AGU)},
	abstract = {Increasing coastal population and industrialization has led to the steady degradation of the Long Island Sound (LIS) environment. Increased nutrient loading from sewage inputs has resulted in eutrophication and decreased summertime subsurface oxygen concentration particularly at its western end. It is critical to develop a detailed history of these environmental changes, both to understand causative processes and for design of optimal and cost effective remediation plans. We are developing a detailed time line of environmental changes in LIS over the last few centuries based on the study of geochemical and paleo-ecological proxies in geographically distributed sediment cores. Sediment nitrogen isotopic ratio (d15N) in particular is being used as an indicator of perturbations of the nitrogen biogeochemistry. Higher d15N is expected from sewage inputs as well as from the initiation of subsurface denitrification during low O2 conditions. Contemporary correlation between eutrophication intensity and d15N is seen in sediment core top data which show a substantial 4 per mil increase in d15N going from eastern to western LIS. This observation is consistent with greater nutrient loading toward New York City with its greater coastal population density. Downcore data from a site in western LIS show 4 per mil lower d15N prior to 200 years ago, documenting the point at which significant anthropogenic impact began. Increasing d15N over the last 200 years correlate with productivity proxies and other proxies for anthropogenic influence},
	author = {Altabet, M. and Varekamp, J. C.}
}
@conference {1729,
	title = {The paleo environmental history of Long Island Sound, Abstract},
	booktitle = {Long Island Sound Lobster Research meeting},
	year = {2003},
	note = {id: 1178},
	month = {2003},
	address = {Groton, CT},
	author = {Varekamp, J. C. and Thomas, E. and Buchholtz ten Brink, M. F. and Altabet, M. and Cooper, S.}
}
