Project Funding: 2014 - 2017

NRA: 2012 NASA: Interdisciplinary Research in Earth Science   

Funded by NASA

Abstract:
The overall goal of this project is to quantify the impacts of human population growth and associated land-use changes on the biogeochemistry and ecology of the Chesapeake and Delaware estuaries and the adjacent continental shelf waters. Our focus will be on these particular estuaries, as they are the most vulnerable in the U.S. because of the high population density in their watersheds and the high degree of climate change they are experiencing, including increases in temperature, sea level, precipitation, and precipitation intensity. To achieve this goal we will refine and link a suite of models including a terrestrial ecosystem model for the watersheds, a coupled biogeochemical- oxygen-circulation model with estuarine grids nested in a shelf model, and shellfish models for both Eastern oysters (Crassostrea virginica) and Atlantic surfclams (Spisula solidissima). We have already calibrated and evaluated these models individually with remote sensing products and historical in situ data. Here we will improve and more fully evaluate the linked modeling system through the analysis of satellite remote sensing products, including phytoplankton functional types, optical properties, and organic carbon cycling. Simulations will extend from the 1950s to the present, allowing us to identify how impacts of land-use changes and climate changes on coastal ecological processes have varied over the past 60 years. The integrated modeling system will be used to generate a core “all processes” simulation, as well as simulations representing: (1)  climate only, including historical climate variability/change while keeping other variables unchanged since the 1950s; (2) land cover change and management practices only, including effects of land conversions while detrending the climate forcing and fixing other input data at 1950s values; and (3) nitrogen input only, including the changing nitrogen fertilization in cropland and nitrogen deposition impacts, while assuming that climate and land-use patterns are held constant at 1950s values. The analysis of these four simulations will allow us to satisfy our overall objective, as well as specific objectives concerning the impacts of human activity in the watershed on the riverine delivery to the coast, phytoplankton speciation, hypoxia, and shellfish. The proposed activity responds fully to Subelement 4 solicited under ROSES 2012 A.31 Interdisciplinary Research in Earth Science (IDS): Impacts of Population Growth on Watersheds and Coastal Ecology, by examining the impacts of increasing human population density and resulting land-use changes on watershed processes including freshwater and nutrient run-off. The effect of these impacts on three broad coastal ecological endpoints will be considered: (1) phytoplankton speciation, representing the base of the coastal food web; (2) Eastern oysters and Atlantic surfclams, upper-trophic keystone species for the region’s estuaries and shelf waters, respectively; and (3) hypoxia, representing an index of threats to the overall health of the region’s ecology. We are an interdisciplinary investigative team including experts in remote sensing analyses, terrestrial and hydrological dynamic modeling, estuarine and coastal biogeochemical- circulation modeling, and shellfish modeling, and thus have the requisite breadth and experience necessary to comprehensively assess impacts of land-use and climate change on the ecology of this important coastal region.

Publications:

Irby, I. D., Friedrichs, M. A. M. 2018. Evaluating Confidence in the Impact of Regulatory Nutrient Reduction on Chesapeake Bay Water Quality. Estuaries and Coasts. 42(1), 16-32. DOI: 10.1007/s12237-018-0440-5

Najjar, R. G., Herrmann, M., Alexander, R., Boyer, E. W., Burdige, D. J., Butman, D., Cai, W., Canuel, E. A., Chen, R. F., Friedrichs, M. A. M., Feagin, R. A., Griffith, P. C., Hinson, A. L., Holmquist, J. R., Hu, X., Kemp, W. M., Kroeger, K. D., Mannino, A., McCallister, S. L., McGillis, W. R., Mulholland, M. R., Pilskaln, C. H., Salisbury, J., Signorini, S. R., St-Laurent, P., Tian, H., Tzortziou, M., Vlahos, P., Wang, Z. A., Zimmerman, R. C. 2018. Carbon Budget of Tidal Wetlands, Estuaries, and Shelf Waters of Eastern North America. Global Biogeochemical Cycles. 32(3), 389-416. DOI: 10.1002/2017GB005790

Poulter, B., Bousquet, P., Canadell, J. G., Ciais, P., Peregon, A., Saunois, M., Arora, V. K., Beerling, D. J., Brovkin, V., Jones, C. D., Joos, F., Gedney, N., Ito, A., Kleinen, T., Koven, C. D., McDonald, K., Melton, J. R., Peng, C., Peng, S., Prigent, C., Schroeder, R., Riley, W. J., Saito, M., Spahni, R., Tian, H., Taylor, L., Viovy, N., Wilton, D., Wiltshire, A., Xu, X., Zhang, B., Zhang, Z., Zhu, Q. 2017. Global wetland contribution to 2000-2012 atmospheric methane growth rate dynamics. Environmental Research Letters. 12(9), 094013. DOI: 10.1088/1748-9326/aa8391

Signorini, S. R., Mannino, A., Friedrichs, M. A. M., St-Laurent, P., Wilkin, J., Tabatabai, A., Najjar, R. G., Hofmann, E. E., Da, F., Tian, H., Yao, Y. 2019. Estuarine Dissolved Organic Carbon Flux From Space: With Application to Chesapeake and Delaware Bays. Journal of Geophysical Research: Oceans. 124(6), 3755-3778. DOI: 10.1029/2018JC014646

Yang, Q., Tian, H., Friedrichs, M. A. M., Hopkinson, C. S., Lu, C., Najjar, R. G. 2015. Increased nitrogen export from eastern North America to the Atlantic Ocean due to climatic and anthropogenic changes during 1901-2008. Journal of Geophysical Research: Biogeosciences. 120(6), 1046-1068. DOI: 10.1002/2014JG002763

More details may be found in the following project profile(s):

• NASA Ocean Biology & Biogeochemistry (OBB) Project Profile