Phytoplankton Ecology Laboratory Interns


Stephanie Ortiz – Summer 2013
 Baylor University,Texas
“Environmental controls on nutrient release rates
from sediments in the Rhode River”

Phytoplankton undergo photosynthetic processes accounting for half of all photosynthetic production in the world. They are the foundation of the aquatic food web, fixing carbon and producing oxygen through primary productivity. Their abilities to support the aquatic food web depend on wave currents, light penetration, amounts of dissolved oxygen in the water and nutrient availability.
Scientists have discovered that an increase in nitrogen and phosphorus going into water systems has occurred from several sources. This process started with industrial waste, farms through field runoff, and improper waste mangement. Nutrient overflow into aquatic systems causes an imbalance in phytoplankton primary productivity, resulting in Eutrophication. An over enrichment of nutrients has led to an increased amount of phytoplankton biomass. This unbalanced level of eutrophication can cause shade depth reduction, hypoxic to possible anoxic conditions and toxic blooms (red tides). Also, from previous studies we noted the influence of dissolved oxygen rates.
These results enticed me to see what kinds of environmental controls, such as stirring to simulate wave currents or low dissolved oxygen directly correlate with nutrient flux rates.



Stephanie Lear – Summer 2012
Montclair State University – New Jersey
“Exploring the factors contributing to spatial variability
 of phytoplankton production in the
 Rhode River subestuary”

Natural processes and human impacts on the environment both influence primary productivity. There is a major input that goes into carbon cycling. Primary productivity is sensitive to carbon cycling, estuarine oceans, eutrophication and acidification.

High water turbidity and deep vertical mixing both, separately and together, limit the light available for algal growth.

Spatial variability is informative to us, as it gives us clues about the shift of the phytoplankton community structure. This also gives us clues to how variable daily primary production is across an area. The goal here is to estimate daily water column primary production and determine its controls on spatial variability.



Kate Pinkerton - Summer 2011 – American University
“Particle effects on Light Scattering
 in the Chesapeake Bay”

We know that the composition of water affects light availability for seagrass. The three optically active components are colored dissolved organic matter (CDOM), suspended particulate matter (SPM), and phytoplankton. Transmitted exopolymer particles (TEP) are a waste product of phytoplankton that also plays a role in light availability. These properties in the water are referred to as “optically active”.
Seagrasses provide habitat and food for Chesapeake Bay species. They are also key to nutrient cycling and protecting the shoreline from erosion by holding sediment in place with their rhizomes, which also reduces the impact of wave energy. Despite the importance of seagrasses, there has been a significant decline in their population over the years in the Chesapeake Bay.



Allison McClain -Summer 2009 - Cedarville University, Ohio
" Non-Photochemical Quenching: Exploring the Affects of NPQ on Phytoplankton Fluorescence

 Water Quality Monitoring through hydro-optics is essential to tracking the health of the Chesapeake Bay.This is especially important in shallow water areas where seagrasses and other SAV's play important roles in promoting the well being of other marine life.
Allison conducted an experiment which explored discrepancies in the relationship between fluorescence and phytoplankon absorption due to a physiological process by phytoplankton called non-photochemical quenching (NPQ). NPQ causes depressions in fluorescence signals at high irradiance levels. Her experiment looked into the extent of NPQ in the bay by comparing true  measurements, and measurements made by a diving PAM fluorometer. Both sets of measurements were put into a water qulity model that generates attenuation coefficients.


Kevin Geyer - Winter 2009 - Michigan State University
"Evaluating Chesapeake Bay Light  Attenuation: Links Between Local Monitoring data and Optical Properties".

To begin with let's define light attenuation. Light attentuation = interaction between absorption and scattering by water itself + its load of optically active dissolved and suspended  constituents.
the water clarity assessment problem refers to the light attenuation criteria for shallow water segments that have been established to achieve SAV (sub-aquatic vegetation) restoration goals. This criteria attainment is assessed by a shallow water monitoring program which monitors turbidity, fluorescence and salinity. Kevin's project was to investigate dependence of NAP absorbtion and light scattering on YSI turbidity as a function of particle-size for laboratory particle suspensions.Also, he studied the preliminary assessment of tool for transforming YSI monitoring data into inherent optical properities and light attenuation coefficients.



Alicia Pritchard -Summer 2008 - St. Mary's College, Maryland
"Effects of Oyster Filtration on Water Clarity:
Some possible Unintended Consequences"

 Increased nutrient and sediment loads in many coastal systems over the last few decades reduced water clarity and the majority of submerged aquatic vegetation (SAV) Many proposals suggest oyster restoration as a solution to poor water clarity in the Chesapeake Bay. Using aquariums, Alicia set up mesocosms to determine the effects of oyster filtration on macroalgae (Ulva Lactuca) growth. She found significantly higher macroalgae growth rates in tanks with oysters than tanks without. Nutrients were added to one tank and there was higher macroalgae growth in it as well. These results indicate that macroalgae could possibly outcompete SAV if water clarity was improved without nutrient reduction.


Kwadwo Omari - Summer 2007 - Kumasi, Ghana
Kwame Nkrumah University of Science and Technology

Kwadwo spent his internship studying the sediment distribution on Muddy Creek and the Rhode River. He found seasonal factors as well as mobile benthic animals causing sediment problems. Using cylinders, as shown in the photo, to enclose a column of water he was able to track the sediment as it settled to the bottom of the creek and in the river. The comparisons between sites indicated that shallow muddy sites may be the source of turbidity for most of the river.

Satish Serchan - Summer 2006 - University of Vermont
Satish is working with calanoid copepod Acartia Tonsa to evaluate their feeding rates on phytoplankton Thalassiosira weissflogii and Prorocentrum minimum at different temperatures and salinity. The project uses data analysis and existing models to evaluate clearance rates by zooplankton assemblage. CASM (comprehensive aquatic ecosystem model) is the pre-existing model that evaluates the consumption of phytoplankton by zooplankton assemblages, the overall goal of this project is to assemble data to re-evaluate CASM and provide a means of predicting grazer feeding responses to changing abundances and species composition of phytoplankton.

Lauren Esposito -Summer 2006 - McDaniel College, Maryland
"Effects of Ithyotoxic Karlodinium  veneficum on Three Species of Rotifers in the Rhode River, Maryland."
Lauren studied the effects of ithyotoxic Karlodinium veneficum on three species of rotifers in the Rhode River, an estuary off the Chesapeake Bay. K. veneficum is a dinoflagellate that causes red tides in the Chesapeake Bay mainly in the late spring to early fall. There are both toxic and non-toxic strains of K. veneficum present in the Chesapeake Bay. Lauren contrasted rotifer responses to another bloom-forming alga, Prorocentrum minimum . This is important because the results will tell us if they are able to distinguish between the toxic strain and non-toxic strain of K. veneficum . If they are able to then the toxic strain have rapid growth and it would potentially increase the threats to other Bay consumers.
(Lauren did her internship with Dr. Kevin Seller of the Chesapeake Reserach Consortium and associate investigator in the Phytoplankton Lab.)

 Amy Kochanowsky - Summer 2005 - University of Virginia
"Comparison of Water Characteristics in the Rhode River and Adjacent Tidal Creeks. "

Amy's project was Comparison of Water Characteristics in the Rhode River and Adjacent Tidal Creeks. Her goals were: Determine attenuation of light by the water column which affects SAV, analyze properties of water that affect phytoplankton growth and measure the rate of photosynthesis by phytoplankton in water samples. This would aid in developing a model for smaller creeks based on their unique characteristics and how they affect the Rhode River and ultimately the Chesapeake Bay.

Augustina Novillo -Spring 2004 - Florida State University
   "The Effects of Bloom Forming Dinoflagellate, Prorocentrum   minimum, on Optical Properties of Water. "

Prorocentrum minimum is a potentially toxic dinoflagellate, and typically the dominant spring blooming species in the mid-salinity waters of the Chesapeake Bay. By growing cultures in the lab, she could compare the data with data collected in the field and estimate the impacts of the bloom on light attenuation .

Sonja Johns - Summer 2004 - Clarkson University, New York
"A study of Alkaline Phosphatase Enzyme Activity in the Rhode River Estuary "

A study of Alkaline Phosphatase Enzyme Activity in the Rhode River Estuary was Sonia's project for the summer.
Her conclusions were; the similarity in dominant species at areas exhibiting large amount of alkaline phosphatase activity, coupled with the erratic trends at all sampling site suggests that species composition may affect alkaline phosphatase activity and alkaline phosphatase activity may be a natural part of the temporal nutrient cycle rather than a sign of phosphate stress

Liz Saunders - Summer 2003 - Autumn 2004
University of Virginia, University North Carolina
for graduate work

Liz chose as her project Predicting Phytoplankton Productivity by Using Optical Modeling in the Rhode River, Tributary to the Chesapeake Bay. She carried forth this project as her senior thesis through the school year.

Returning to SERC in autumn 2004, her objective was to attempt to resolve a model to predict phytoplankton maximum photosynthetic rate on a rapid time scale for shallow, turbid estuaries.

Robin Barnes - Summer 2002 - Winter 2003
Humbolt University, SUNY for graduate work

Robin's summer project was Total Suspended Solids and Chromophoric Dissolved Organic Matter: Two Experiments on their Relationship to Light Penetration.

When she returned for her second Internship she followed a similar hypotheses as her first project; "Influence of particle size on specific -absorption and scattering coefficients of non-algal particulate matter.

Tina Fedarcyk - Summer 2001 - Notre Dame University
South Bend, Indiana

Using SERC designed benthic containers, Tina's project was to determine grazing by benthic microzooplankton on phytoplankton. She took chlorophyll readings before and after the containers were situated on the bottom in the Rhode River, which allowed her to determine any phytoplankton growth or demise from microzooplankton grazing. She also determined phosphate release from the benthos and how it affected growth of phytoplankton

Erin Turack Cosky- Spring 1999 - Kentucky University
San Diego State University teaching degree.

Erin developed our Hydrologic Primer web pages. Erin is currently in her second year teaching Marine Biology at Gulf Breeze High School in Sarasota, Florida. She has also worked as a lab assistant at Scripps Institute of Oceanography in the Phytoplankton Biolumenscence laboratory with Dr. Mike Latz.