Changes in forest structure in urban and rural forest stands in the Baltimore Metropolitan area from 1998 to 2015

Presenter: Laura Templeton                                   Status: Graduate Student

Authors: Laura Templeton, Jenifer Mallinoff, Maile Neel, Peter Groffman, Joseph Sullivan


Abstract:   In 1998, the Baltimore Ecosystems Survey (BES) established eight long-term plots within four forested sites in the Baltimore metropolitan area as part of the National Science Foundation’s Long-Term Ecological Research (LTER) network.  The eight permanent plots are composed of four urban plots located within Baltimore City and four rural plots in Baltimore County.  One of the objectives of the BES in establishing these two different plot types was to examine the influence of urban land use on forested ecosystems.  After seventeen years, we decided to revisit these plots with the objective of determining the effect of time, as well as urbanization, on trees and saplings in the plots.  Our hypothesis was that there would be further divergence in forest community structure between the two plot types. In this study, we found that the interplay of time and urbanization had strong effects on tree and sapling diversity, abundance, and assemblages.  


Examining the Relationship between Cell Volume and Cell Biomass in Freshwater Green Algae

Presenter: Andrew Park                              Status: Undergraduate Student

Authors: Andrew S. Park, Charles F. Delwiche


Abstract: The use of fossil fuels has long since been marked as a detrimental energy source. It is known to increase green house gases (GHGs) and cause global warming. The world is in dire need of a renewable and safe source of energy. One of the leading renewable resources today is biofuels, which can be retrieved from the biomass extracted from different microorganisms, such as green algae. Despite the relevance of biofuels today, research is lacking in algal physiology. Understanding patterns in algal biomass will be beneficial in understanding the role of green algae in global warming and its effectiveness as biofuel. The main goal of this research is therefore, to determine the relationship between biovolume and biomass in green algae and see if this relationship can be exploited to make accurate biomass estimations in wild samples. In order to view only the relationship between biovolume and biomass, the cell count was equalized through cell count measurements using a coulter counter. The biovolume was then calculated using geometric modeling of the cells. Biomass was determined through dry weight measurements after careful sample dehydration. The results indicate that that there is a direct relationship between biomass and biovolume in freshwater green algae. The relationship shown in the results suggests that a conversion factor of 0.0002 mg μm-3 can be used to estimate biomass.