Science Serving Maryland's Coasts

REU Mentor Profile: Cindy Palinkas

Cindy Palinkas, Ph.D.

Horn Point Laboratory

See Dr. Palinkas' expertise, education, and contact information on her website.

REU Student Abstracts

Browse these abstracts describing the research of past REU students for whom Dr. Palinkas served as a mentor.

Stella Castro, Universidad Metropolitana (2014)

Nicholas Taylor, University of Virginia (2013)

The Evaluation of Basic Calculations Concerning the Effects of Non-storm Waves on Offshore Sediment at Jefferson-Patterson Park, MD

Benjamin Green, University of Iowa (2012)

Sedimentation trends and their effect on nitrogen burial in the lower Potomac River

Nitrogen burial through sediment accumulation is a major sink within the proposed nitrogen cycle for the Potomac River. This study explored the relationship between nitrogen concentration and deposition patterns. 210Pb geochronology was used to calculate sedimentation rates for sediment cores collected in the Potomac River. There were examples of both steady-state accumulation and event-layer deposition at different points along the river. Upon further analysis, it was found that sediment deposition patterns have a direct relationship to the rates of nitrogen burial. It is postulated that either channel location or river position affects dominant deposition patterns, with differences also noted in profiles of median grain size profiles and nitrogen concentration profiles.

Andrea Eglinton, Gustavus Adolphus College (2011)

Potential Sediment Exchange between Marshes and Adjacent Submersed Aquatic Vegetation (SAV) Beds

In the recent years coastal marshes and submersed aquatic vegetation (SAV) beds within the Chesapeake Bay have been declining with rising sea level and warming of the bay. Understanding what is affecting deposition in the marshes could help the efforts being made to preserve them, and sediment provided from SAV diebacks could be playing a major role. A transect of cores, one within the SAV bed and four within the marsh, were taken and analyzed for median grain size and organic content. This along with 210Pb dating was used to assess possible linkages between the SAV bed and the marsh. The SAV core was represented by large median grain size (1-2 phi) and low organic content (<10%), with two separate dieback events represented. These events occurred from 2005-2008 and 2010-2011 and thinned out landward of the SAV bed. Prior to 2005 there were no SAV dieback events to be seen, but with the rising temperature they are now providing a large amount of sediment to the marsh.

David Walters, Longwood University (2010)

Effect of elevation on sedimentation in a tidal freshwater wetlands system

Wetlands have been diminishing throughout the world due to poor management practices and sea-level rise. It is important to study the wetlands' ability to rebound from this, and accumulate sediment in order to keep up with sea-level rise. Research on freshwater tidal wetlands is much less cohesive in this area. This study seeks to determine what factors affect sedimentation rates in freshwater tidal wetlands both spatially and temporally. The wetlands studied in this research project are located in Dyke Marsh Preserve in Alexandria, VA. We hypothesized that sedimentation rates would be higher at sites with lower elevation, as well as over monthly time scales in comparison to decadal time scales. To analyze these nested time scales, ceramic tiles were placed in the sediment so they could collect sediment over a monthly scale. Decadal scale rates were determined by analyzing sediment cores for 210Pb activity, and plotting the rates using linear regression. Sites at lower elevations did prove to have higher rates than the sites in the high marsh area. However, the monthly scale rates were actually lower than the decadal scale rates in most cases. This is likely because the sampling period did not include the prime depositional period of the year during the growing season. The major conclusion of this paper is that sedimentation rates are highest at sites in low elevation, located close to their sediment source, because they receive regular delivery of sediment through tidal flooding events.

Cristina Hernandez Gonzalez, University of Puerto Rico (2009)

The Role of Marshes in the Sediment Budget of the Corsica River, Maryland

To determine the role of the marshes in the sediment cycling of the Corsica River, 210Pb analyses were carried out and accumulation rates were calculated. Organic matter percent and total phosphorous analyses were also done to the samples. Four cores were collected from different sites in the marsh for comparison. Site one was in the bank and site two in the inside of the marsh. Site three is located upstream and site four is downstream. Accumulation rates from the sites one and two were ~7-9mm/y, which is higher than the average rate of sea level rise in this region ~3-4 mm/yr. Site three changed its rate through the core; in the top we calculated 2.0 mm/y and at the bottom 5.8 mm/y, with a long-term average of 3.8 mm/y. Because of this decrease, this marsh site may disappear with time. Site four showed the highest of all the accumulation rates; 2.3 cm/y. The organic matter percent increases generally upward in cores. We also did total phosphorus analysis while the data should be considered qualitative, values do increase upward with the highest values observed at the base of site 4.

Caroline Baumgartner, Muhlenberg College (2008)

Sediment Grain Size in Current and Historical Sav Beds of the Chesapeake

The drastic decline of seagrasses and other submerged aquatic vegetation (SAV) in the Chesapeake Bay over the last century is a major concern and has sparked both research and restoration efforts to combat the problem. Due to previous studies, distribution is known to be heavily affected by water quality factors such as light availability, salinity, temperature and depth. Sediment type, although secondary, also seems to be a contributing factor. In this study, pushcores were taken at two sites with stable SAV beds, Trippe Bay and Crab Alley Bay, and at two sites that had previously contained historical beds, Casson Point and Herring Bay. Samples were then separated at 0.5-1 cm depth increments and each interval wet sieved at 64 μm and dried to determine the mud and sand portions. Dry sieving was used to determine the particle size distribution within the sand component for each interval. Both stable sites were found to have well-sorted surface sediment with the majority of particles falling between 106-150 μm. The historical site Casson Point did have a slight fining trend, while Herring Bay remained constant. The grain-size profiles for the stable sites Trippe Bay and Crab Alley Bay were also relatively constant (except for the fine top layer which may have been deposited because of the current-slowing beds). Total sand content near the surface was variable between all sites, ranging from 78-96%.

Monica Wright, University of Maryland Baltimore County (2007)

Sedimentation in St. Martin River and Blackwater National Wildlife Refuge

Sediment cores were collected in St. Martin River and Blackwater National Wildlife Refuge (BNWR) to determine sediment accumulation rates and textural properties. One core was collected and analyzed from St. Martin (SM14), and two were collected and analyzed from the open-water area of BNWR (Lake Blackwater; cores BW3 and BW4). SM14 and BW4 have similar textural properties, consisting mostly of fine-grained mineral sediments. Also, the grain-size profile for BW4 shows upward fining, which is characteristic of channel-fill deposits, suggesting that BW4 was located in a relict river channel. In contrast, the other BNWR core (BW3) is mostly composed of organic material (i.e., peat), which is probably composed of eroded marsh material. The mass accumulation rate for BW3 is 0.5 g/cm2/y, which, if extrapolated to the entire Lake Blackwater area, would account for ~50% of the estimated export of sediment from the adjacent marshes by previous studies. The BNWR results demonstrate the high spatial variability present in Lake Blackwater sediments and the need for further research. In St. Martin River, the sediment accumulation rate at SM14 is ~3 mm/y, which is similar to the average rate of sea-level rise in the Chesapeake Bay region, indicating that this area is keeping up with sea-level rise. However, rapid population growth and high nutrient loading in recent years are likely to have impacts on shorter-term (<100 y) sedimentation processes.

Colette LeBeau, Maine Maritime Academy (2006)

Geochronology and characterization of grain size and trace metals in sediment cores collected from the Corsica River, Maryland 

Flow, erosion, and bioturbation affect sedimentation in rivers. Metals can react with sediment particles and be deposited with the sediment. The Corsica River in Maryland is highly polluted from erosion and waste disposal, amongst other things. To determine the changes in sedimentation in the Corsica River over the past 100 y, two cores were collected from different locations on the river. Both cores were analyzed for grain size using a Sedigraph, and an alpha counter was used to analyze 210Pb. The downstream core was analyzed for the trace metals Pb, Cu, Zn, Mn, and Fe with a flame atomic absorption spectrometer. The results show that the downstream core has more sand in the surface layers, possibly from higher river flow. The upstream core has more clay and a higher sediment accumulation rate, indicating lower flow. Bioturbation is the primary cause of mixing in the top 12 to 16 cm of both cores. The increase in Pb, Cu, and Zn over time is directly related to the increase in industrialization and pollution. However, in recent years, the concentrations of Pb and Zn decrease due to pollution regulations. Mn concentrations correspond to concentrations of pyrite, suggesting that Mn is incorporated into pyrite. Fe concentrations show no pattern. Overall, the concentrations of all the metals analyzed were low relative to those of the Chesapeake Bay and Baltimore Harbor, suggesting that metals are not a major source of pollution in the Corsica River.

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