I am an early career scientist with a focus on land-estuary-ocean biogeochemistry and carbon cycling. I completed my PhD in 2019 at the University of Maryland Center for Environmental Science, Horn Point Lab under the advice of Dr. Raleigh Hood. There, I worked on developing and applying a model that represented the processes of tidal inundation and marsh-estuary linkages and organic matter cycling. Upon graduation in 2019, I began a NASA Postdoctoral Program fellowship at Goddard in the Ocean Ecology Lab with Antonio Mannino as my advisor. My work continues to focus on integrating biogeochemical modeling and satellite remote sensing to measure and predict coastal carbon properties. I have projects in the Yukon River, Alaska, the Arctic Ocean, and the Chesapeake Bay.
Coastal organic carbon cycling
My research focuses on carbon cycling in the coastal ocean. I use process-based experiments to construct and inform biogeochemical models to investigate carbon cycling on multiple time and space skills. I have ongoing research in the Chesapeake Bay estimating organic matter cycling and fluxes in a tidal marsh influenced estuary, focusing on the export of dissolved organic matter from marshes and the role tidal marshes play in estuarine biogeochemistry. My current focus has shifted to the Arctic where I am taking my skills developed in Chesapeake Bay and applying them to study the organic carbon dynamics of the Yukon River plume.
Biogeochemical model development
Incorporating new and important processes into biogeochemical models requires precise field and laboratory measurements to inform mathematical models. Part of my work focuses on identifying current gaps in the biogeochemical modeling frameworks we use. Once identified, targeted sampling and experiments can build data sets that can be used to build a mathematical model. These mathematical models can be implemented on multiple scales to quantify the importance of any given process to elemental cycling as a whole.
3/2019
-
4/2021
Postdoctoral Fellow
Universities Space Research Association,
NASA Goddard Space Flight Center
4/2021
-
11/2021
Associate Scientist
Universities Space Research Association,
NASA Goddard Space Flight Center
12/2021
-
Present
Assistant Research Scientist
University of Maryland Baltimore County,
NASA Goddard Space Flight Center
Arctic Ocean organic matter dynamics by integrating field and satellite observations into a three-dimensional hydrodynamic-biogeochemical model.
The coastal Arctic Ocean is undergoing rapid changes due to increased warming, loss of sea ice, high rates of erosion and enhanced river discharge. Understanding these processes and the impact they have in the coastal ocean is key to predicting how Arctic water quality, carbon cycling and watershed-ocean interactions will change in the future. This research project aims to utilize data generated from ongoing field campaigns and satellite remote sensing (RS) products of chl a and dissolved and particulate organic matter (DOM & POM) in the coastal Arctic Ocean to estimate carbon fluxes using multiple combined hydrodynamic-biogeochemical modeling and RS techniques. First, predicted water transport from a newly built Yukon River regional hydrodynamic model (YukonFVCOM) will be combined with satellite ocean color organic matter (OM) concen-tration products to calculate OM fluxes near the Yukon river outflow and in Norton Sound. Second, the OM cycling model ICM-DOM-PD will be coupled with YukonFVCOM to corroborate and bolster estimates of OM distribution and fluxes in the Yukon River coastal region at multiple spatial and temporal scales. Model OM reaction kinetics will be re-parameterized to represent Arctic Ocean processes using data collected in the 2018 and 2019 field campaigns under a currently funded NASA Remote Sensing of Water Quality proposal, NNH16ZDA001N-RSWQ (PIs: Hernes, Mannino, Spencer and Tzortziou), in addition to relevant field data from the NASA SeaBASS archives. Specific locations along the river-delta-sea gradient where and timing when modeled OM undergoes rapid transformation will be identified, informing future large scale efforts such as the Arctic-COL-ORS project. Results from the RS and modeling efforts will be used to establish a baseline of current conditions to inform future studies and biogeochemical model forecasts that project how the Arctic carbon cycle will change in the future.
New Observing Systems - Oceans
This project is an interdisciplinary effort between a science team and engineering team to develop and demonstrate how integrated observations of a coastal system can be used to better understand and predict the coastal carbon cycle. My role on the team is to help define the science objectives and the observational (current and future) needed to observe event driven (e.g. storm events) large land-estuary-ocean export of carbon and nitrogen and the potential for nutrient induced phytoplankton blooms on the continental shelf.
Doctor of Philosophy. Marine Estuary Environmental Science: Focus in Biogeochemistry and Oceanography. Horn Point Laboratory, University of Maryland Center for Environmental Science, Cambridge, MD. September 2014 – May 2019. Advisor: Professor Raleigh Hood
Bachelor of Science, Aquatic Biology. University of California at Santa Barbara, Santa Barbara, CA. September 2008 - September 2012. Advisor: Professor Craig Carlson
American Society of Limnology and Oceanography,
2017
-
Present
American Geophysical Union,
2019
-
Present
Coastal and Estuarine Research Federation,
2017
-
Present
Chesapeake Bay Program Scientific and Technical Advisory Committee (STAC) “Assessing the environment in outcome units” workshop. Invited Participant Annapolis, MD. March 20-21, 2019.
Chesapeake Bay Program Scientific and Technical Advisory Committee (STAC) “Chesapeake Bay Program Climate Change Modeling 2.0 workshop.” Invited Participant Annapolis, MD. September 24-25, 2018
NASA Goddard Earth Science Peer Award - 2021
NASA Postdoctoral Fellowship - 2019
University of Maryland College of Computer, Mathematical and Natural Science Merit fellowship - 2017
Horn Point Laboratory Graduate Student Research Fellowship - 2017
University of Maryland Graduate School Dean’s Fellowship - 2018
Refereed
Clark, J. B., A. Mannino, M. Tzortziou, R. G. Spencer, and P. Hernes. 2022. "The Transformation and Export of Organic Carbon Across an Arctic River‐Delta‐Ocean Continuum."
Journal of Geophysical Research: Biogeosciences,
127
(12):
[10.1029/2022jg007139]
Novak, M. G., A. Mannino, J. B. Clark, et al. 2022. "Arctic biogeochemical and optical properties of dissolved organic matter across river to sea gradients."
Frontiers in Marine Science,
9:
[10.3389/fmars.2022.949034]
Clark, J. B., and A. Mannino. 2022. "The Impacts of Freshwater Input and Surface Wind Velocity on the Strength and Extent of a Large High Latitude River Plume."
Frontiers in Marine Science,
8:
[10.3389/fmars.2021.793217]
Logozzo, L., M. Tzortziou, P. Neale, and J. B. Clark. 2021. "Photochemical and Microbial Degradation of Chromophoric Dissolved Organic Matter Exported From Tidal Marshes."
Journal of Geophysical Research: Biogeosciences,
126
(4):
[10.1029/2020jg005744]
Clark, J. B., and A. Mannino. 2021. "Preferential loss of Yukon River delta colored dissolved organic matter under nutrient replete conditions."
Limnology and Oceanography,
lno.11706
[10.1002/lno.11706]
Clark, J. B., W. Long, and R. R. Hood. 2020. "A Comprehensive Estuarine Dissolved Organic Carbon Budget Using an Enhanced Biogeochemical Model."
Journal of Geophysical Research: Biogeosciences,
125
(5):
[10.1029/2019jg005442]
Clark, J. B., P. Neale, M. Tzortziou, F. Cao, and R. R. Hood. 2019. "A mechanistic model of photochemical transformation and degradation of colored dissolved organic matter."
Marine Chemistry,
214:
103666
[10.1016/j.marchem.2019.103666]
Clark, J. B., W. Long, and R. R. Hood. 2017. "Estuarine Sediment Dissolved Organic Matter Dynamics in an Enhanced Sediment Flux Model."
Journal of Geophysical Research: Biogeosciences,
122
(10):
2669-2682
[10.1002/2017jg003800]
Clark, J. B., W. Long, M. Tzortziou, P. J. Neale, and R. R. Hood. 2017. "Wind-Driven Dissolved Organic Matter Dynamics in a Chesapeake Bay Tidal Marsh-Estuary System."
Estuaries and Coasts,
41
(3):
708-723
[10.1007/s12237-017-0295-1]
Testa, J. M., J. B. Clark, W. C. Dennison, et al. 2017. "Ecological Forecasting and the Science of Hypoxia in Chesapeake Bay."
BioScience,
67
(7):
614-626
[10.1093/biosci/bix048]
Invited
Modeling of Organic Carbon Export and Processing in Arctic Deltas, Plumes and Coastal
Ocean.
10
/
19
/
2021
Arctic-COLORS Data Synthesis Meeting
Linking optics to biogeochemical models to better quantify marine carbon cycling
6
/
22
/
2021
Ocean Carbon and Biogeochemistry Annual Workshop
Estimating the fluxes and controls of estuarine organic matter: a case study of the Rhode River, MD. Invited Seminar. GCReW Symposium. Smithsonian Environmental Research, Edgewater, MD.
3
/
28
/
2019
Estimates of wetland-estuary organic matter cycling using a new biogeochemical modeling system. Invited Seminar. Virginia Institute of Marine Science, College of William and Mary, Gloucester, VA.
8
/
22
/
2018
Modeling organic carbon at the wetland estuary interface – A small model with large insights. Invited Seminar. Smithsonian Environmental Research Center, Edgewater, MD
12
/
11
/
2017
Progress and challenges in up-scaling carbon modeling to a regionally significant wetland-estuary system. Lightning talk. Ocean Carbon and Biogeochemistry Workshop, Woods Hole, MA.
6
/
24
/
2017
Other
Activities for Teaching Estuarine Ecosystem Simulation Modeling.
11
/
5
/
2021
Coastal and
Estuarine Research Federation Biennial Meeting
Modeling of Organic Carbon Export and Processing in the Yukon River Delta and Coastal
Ocean.
5
/
4
/
2021
Quarterly Changes in the Arctic and Boreal System meeting
Biodegradation of Yukon River delta dissolved organic matter is marginally
enhanced by nutrient enrichment.
2
/
19
/
2020
Ocean Sciences Meeting
Modeling of complex flow patterns across a large wetland-estuarine complex in Southern Dorchester Co, MD. Oral Presentation. Chesapeake Research and Modeling Symposium. Annapolis, MD.
6
/
14
/
2018
Modeling of complex flow patterns across a large wetland-estuarine complex in Southern Dorchester Co, MD. Oral Presentation. Atlantic Estuarine Research Society Biennial Meeting. Rehoboth, DE
4
/
6
/
2018
Development and application of a mechanistic model of the photochemical degradation of colored dissolved organic matter. Oral presentation. Ocean Sciences Meeting, Portland, OR.
2
/
14
/
2018
Modeling of photodegradation and biogeochemical cycling in a wetland-estuary system. Oral. Coastal and Estuarine Research Federation Biennial Conference, Providence, RI.
11
/
7
/
2017
Insights gained from a wetland-estuary dissolved organic matter modeling system. Poster. Ocean Carbon and Biogeochemistry Workshop, Woods Hole, MA.
6
/
26
/
2017
Modeling of estuarine sediment organic matter remineralization with a dissolved organic matter intermediate state variable. Oral. Aquatic Sciences Meeting, Honolulu, HI
3
/
1
/
2017
Mass conservative modeling of dissolved organic matter photochemistry and biogeochemical cycling. Poster. Ocean Carbon and Biogeochemistry Workshop, Woods Hole, MA.
7
/
27
/
2016
Modeling the marsh-estuary organic carbon cycle in the Rhode River, MD. Oral. Chesapeake Modeling Symposium, Williamsburg, VA.
6
/
1
/
2016
Atmospheric forcing and marsh dissolved organic matter fluxes: modeling and observations from a Chesapeake Bay tidal marsh-estuary ecosystem. Poster. Ocean Sciences Meeting, New Orleans, LA.
2
/
25
/
2016
Three-dimensional modeling of a Chesapeake Bay tidal marsh Ecosystem, Oral Finite Volume Community Ocean Model (FVCOM) User workshop. Bedford Institute of Oceanography, Halifax, NS, CAN.
10
/
21
/
2015
Three-dimensional modeling of a Chesapeake Bay tidal marsh Ecosystem. Poster Community Surface Dynamic Modeling Systems (CSDMS) Annual Meeting. National Center for Atmospheric Research, Boulder, CO.
5
/
27
/
2015
Refereed
Clark, J. B., A. Mannino, M. Tzortziou, R. G. Spencer, and P. Hernes. 2022. "The Transformation and Export of Organic Carbon Across an Arctic River‐Delta‐Ocean Continuum."
Journal of Geophysical Research: Biogeosciences
127
(12):
[10.1029/2022jg007139]
Novak, M. G., A. Mannino, J. B. Clark, et al. 2022. "Arctic biogeochemical and optical properties of dissolved organic matter across river to sea gradients."
Frontiers in Marine Science
9
[10.3389/fmars.2022.949034]
Clark, J. B., and A. Mannino. 2022. "The Impacts of Freshwater Input and Surface Wind Velocity on the Strength and Extent of a Large High Latitude River Plume."
Frontiers in Marine Science
8
[10.3389/fmars.2021.793217]
Logozzo, L., M. Tzortziou, P. Neale, and J. B. Clark. 2021. "Photochemical and Microbial Degradation of Chromophoric Dissolved Organic Matter Exported From Tidal Marshes."
Journal of Geophysical Research: Biogeosciences
126
(4):
[10.1029/2020jg005744]
Clark, J. B., and A. Mannino. 2021. "Preferential loss of Yukon River delta colored dissolved organic matter under nutrient replete conditions."
Limnology and Oceanography
lno.11706
[10.1002/lno.11706]
Clark, J. B., W. Long, and R. R. Hood. 2020. "A Comprehensive Estuarine Dissolved Organic Carbon Budget Using an Enhanced Biogeochemical Model."
Journal of Geophysical Research: Biogeosciences
125
(5):
[10.1029/2019jg005442]
Clark, J. B., P. Neale, M. Tzortziou, F. Cao, and R. R. Hood. 2019. "A mechanistic model of photochemical transformation and degradation of colored dissolved organic matter."
Marine Chemistry
214
103666
[10.1016/j.marchem.2019.103666]
Clark, J. B., W. Long, and R. R. Hood. 2017. "Estuarine Sediment Dissolved Organic Matter Dynamics in an Enhanced Sediment Flux Model."
Journal of Geophysical Research: Biogeosciences
122
(10):
2669-2682
[10.1002/2017jg003800]
Clark, J. B., W. Long, M. Tzortziou, P. J. Neale, and R. R. Hood. 2017. "Wind-Driven Dissolved Organic Matter Dynamics in a Chesapeake Bay Tidal Marsh-Estuary System."
Estuaries and Coasts
41
(3):
708-723
[10.1007/s12237-017-0295-1]
Testa, J. M., J. B. Clark, W. C. Dennison, et al. 2017. "Ecological Forecasting and the Science of Hypoxia in Chesapeake Bay."
BioScience
67
(7):
614-626
[10.1093/biosci/bix048]
