Directory Page Title

Samuel J. Lake

Fellowship & Research Program Coordinator

Email: [[sjlake]]
Phone: (804) 684-7436
Office: Maury Hall 211
Department: Virginia Sea Grant

Education

Doctor of Philosophy; Marine Science, May 2013
Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia
Dissertation: Modeling the Formation of Periodic Hypoxia in Partially Mixed Estuaries and its Response to Oligotrophication and Climate Change. Advisor: Mark J. Brush

Bachelor of Science; Marine Science and Biology, Minor: Chemistry. May 2005
Coastal Carolina University, Conway, South Carolina

Research Interests

A complex field such as oceanography tends to be subject to two opposite approaches.
The first is the descriptive, in which several quantities are measured simultaneously
and their inter-relationships derived by some sort of statistical method.
The other approach is the synthetic one, in which a few reasonable
although perhaps oversimplified assumptions are laid down,
these serving as a basis for mathematical derivation of relationships.”

- Gordon A. Riley (1946)
Journal of Marine Research 6:54-73

I am a marine ecosystem ecologist who strives to maintain a unified balance between these two complementary approaches described by Gordon Riley.  While much of my work is centered on developing whole system budgets and utilizing interdisciplinary numerical models, it is always closely linked to observational studies that involve field and lab components as well as empirical data analysis.  My primary research focuses on examining how coastal marine systems respond to nutrient enrichment, the processes of eutrophication and oligotrophication, the development of hypoxia/anoxia, and climate change, with an emphasis on developing new methods to both enhance our understanding and inform management.  Additionally, I have embraced the recent calls for future marine eutrophication research to focus on multiple stressors acting in concert.  I am also interested in the interactive relationships between smaller sub-estuaries that receive inputs from both “near-field” sources (upland tributaries and surrounding watersheds), as well as “far-field” sources (i.e. the larger adjacent estuaries – for example the Chesapeake Bay), which often play a significant role in controlling how these sub-systems function.

Lab Website

Coastal Systems Ecology and Modeling Program

Current Projects

Defense / Coastal Estuarine Research Program (DCERP)

My work on the DCERP project is focused on demonstrating the utility of intermediate-complexity ecosystem models by developing system-specific models for estuaries bordered by Department of Defense installations.  For this project I am adapting and calibrating our ecosystem model to the Neuse River estuary in North Carolina and to the Pensacola, Escambia, and Choctawhatchee Bays in Florida.  The development of these additional models, combined with our previous projects, will demonstrate the broad applicability of this approach in systems from New England to the Gulf of Mexico.  Ultimately, we plan to utilize this unique approach and extensive range of ecosystems to study the potential changes within these systems due to future climate and land use changes.  I will also be helping to translate these models into online decision-support tools for estuarine nutrient and carbon reductions.

Microphytobenthos Surveys and Model Development

During my time at VIMS I have conducted a six year running survey of microphytobenthic biomass at seven sites along the shallow, photic shoals that line the York River estuary.  As a supplement to this work, I additionally conducted randomized seasonal surveys that incorporated depth profile sampling to quantify the spatial variability within the system.  This long-term data set was used to constrain a recently developed mechanistic model of microphytobenthos utilizing my work in the York River estuary, along with measurements made in the New River estuary, NC and the lagoons of the Delmarva Peninsula.  We are currently in the process of refining this model and will be submitting it for publication.

Dissertation and Past Research

Internal and External Drivers of Periodic Hypoxia in a Coastal Plain Tributary Estuary

This project utilized metabolic incubations and high spatial resolution sampling to assess the role of internal respiration versus the advection of low oxygen water from the lower Chesapeake Bay.  After confirming that internal respiration alone was capable of driving this system to hypoxia, I focused on evaluating the individual importance of various autochthonous and allochthonous organic matter sources that ultimately drive this system to hypoxia.  My results indicated that management efforts focused on alleviating hypoxia should focus on reducing internal phytoplankton production, while the input of labile organic matter from the Chesapeake Bay represented an important additional source that can only be controlled by more regional efforts. The results of this project have been published in Marine Ecological Progressive Series.

Modeling the Contribution of Multiple Organic Matter Sources to the Development of Periodic Hypoxia

After establishing the relative importance of various organic matter sources, I then focused on the significance of both “near-field” and “far-field” nutrient and organic matter sources in relation to the development of hypoxia.  While most management strategies focus solely on controlling inputs from the watersheds, I was particularly interested in evaluating the contribution of advected water entering from the Chesapeake Bay, by utilizing an intermediate-complexity model.  My analysis employed a series of nutrient and organic matter loading scenarios to isolate the importance of each source to the development of hypoxia in eight regions of the estuary.  After evaluating the relative contribution of each source, I evaluated the effectiveness of a range of nutrient and organic matter load reductions to determine what actions may be necessary to meet the established water quality criteria in different parts of the system.  The results of this project have been submitted to Estuaries and Coasts.

Modeling the Response to External Load Reductions in a Warmer Climate

This study highlighting the importance of climate change, which has the potential to complicate ongoing efforts to restore estuaries solely through nutrient load reductions.  This study utilized the water quality model developed for the York River estuary to quantify the effects of climate warming on primary production, net ecosystem metabolism, and the development of hypoxia.  The model predicted an increase in the duration and spatial extent of low oxygen under climate warming, and confirmed the results from the previous study that a multifaceted management strategy is required to improve conditions in the York River.  However, simulations suggested that climate warming will require additional load reductions beyond those required to mitigate hypoxia in the absence of warming. The results of this project have been submitted to Estuaries and Coasts.

Contribution of Microphytobenthos to Total Productivity in Upper Narragansett Bay

This work focused on examining the importance of microphytobenthic production in Narragansett Bay.  While numerous past studies have examined the role of water column primary production, there had not been an attempt to quantify benthic production occurring on the extensive shallow, photic shoals that line the upper portions of the Bay.  I compared my measured metabolic rates to recent water column rates and estimated the contribution of benthic production to total primary production under current conditions and discussed the future role of microphytobenthos in the upper bay with continued oligotrophication and climate change. This analysis was also critical to establishing the importance of microphytobenthos to support future comparative and modeling analyses. The results of this project have been published in Estuarine, Coastal and Shelf Science.

Recent Publications
Professional Committees/Positions
2013   Co-host and Co-coordinator for the Spring 2013 Atlantic Estuarine Research Society Meeting
2011 - 2012: VIMS Graduate Student Association Treasurer
2011 - 2012: Student Dive Safety Board Representative
2007 - 2010: VIMS / W&M Rec. Sports Club President
2007 - 2009: VIMS Student Representative for W&M Student Assembly
Teaching and Mentoring Experience
  • Jenna Mercier, 2013 – 2014 academic year. Governor’s School for Science and Technology (GSST) student. “Seasonal Variations in Water Column Respiration Rates in the lower York River estuary and Methodological Testing of Sample Volume and Incubation Time.”
  • Jennifer Radcliffe, Fall 2013. Governor’s School for Science and Technology (GSST) student. “Measuring the Effect of pH on Metabolic Rates of Hydrilla: as an Indicator for Future Ocean Acidification.”
  • Alma C. Ramirez Velez, Summer 2013. VIMS Research Experience for Undergraduates Program Co-mentor. “Effects of Outwelling on the Metabolism of the York River Estuary, VA.”
  • Jennifer Radcliffe, Summer 2013. Virginia Department of Education’s Summer Governor’s School Project Co-mentored: “Outwelling and Net Ecosystem Metabolism in Taskinas Creek.”
  • Teaching Assistant, Spring 2013. Interdisciplinary Research in Estuarine and Coastal Systems (MSCI 503). Professor: Dr. Mark Brush.
  • Scientific Mentor, NASA Sponsored Program, Summer 2012- Simulation Based Engineering and Science - Teacher Professional Development Program. Mentored 2 high school teachers developing an interdisciplinary (math and biology) lesson that incorporated phytoplankton population dynamics with “easy to understand” mathematical relationships.
  • National Science Foundation "VIMS PERFECT" GK-12 Fellow, 2011 - 2012 academic year. Worked with Kristen Kelly at York High School, Virginia.
  • Tatum Conner, Fall 2010. York High School student: “Determining the effect of petroleum products on light attenuation and phytoplankton biomass at selected PAR wavelengths.”
  • National Science Foundation "VIMS PERFECT" GK-12 Fellow, 2010 - 2011 academic year. Worked with Amy Holtschneider at York High School, Virginia.
  • Teaching Assistant, Spring 2010. Interdisciplinary Research in Estuarine and Coastal Systems (MSCI 503). Professors: Dr. Mark Brush and Dr. Jesse McNinch.
  • Research Assistant (Surfnaut) on Project "Sea CAMEL", Fall 2007. Classroom Aquarius Marine Education Live - 3 day interactive coral-reef experiment from Aquarius Underwater Laboratory, broadcasted live as an educational experience.
  • NSF and Sea Grant Fellow, Summer 2004. Co-sponsored project ‘Rising Tide’ aimed at linking local teachers, professors and graduate students in an effort to build current scientific research into high school curricula. “Examining the Ecology of Coastal South Carolina Salt Marsh Environments”
Advisory Service and Professional Outreach
  • Guest lecturer in Grafton High School Environmental Science Courses, 2010 – 2014. Developed and led water quality unit including presentations, discussions and outdoor sampling activities centered on local aquatic ecosystems.
  • Presenter at William and Mary’s Focusing on the Future Program, February 2014. A career and academic planning experience for high-ability students in grades 6-12 and their parents. Presented and discussed various marine science careers.
  • Co-presenter at William and Mary’s Focusing on the Future Program, February 2013. A career and academic planning experience for high-ability students in grades 6-12 and their parents. Presented and discussed various marine science careers.
  • Organizer and presenter at York High School’s Marine Science Day Forum, May 2012. A graduate student run event that invites local professors, graduate students, and federal employees who work in marine related fields to interact with high school students through a “speed-dating” forum, so that students can learn more about various marine fields, ask questions and make connects for their future careers.
  • Presenter at York High School’s Marine Science Day Forum, May 2011. A graduate student run event that invites local professors and graduate students who work in marine related fields to interact with high school students through a “speed-dating” forum, so that students can learn more about various marine fields, ask questions, and make connects for their future careers. 
Professional Memberships