Many aquatic plants produce copious amounts of dissolved organic matter (DOM) which enters surrounding waters and potentially stimulates planktonic activity. In the northern Gulf of Mexico, Juncus roemarianus (i.e. black needlerush) is a dominant marsh grass species residing in coastal zones and barrier islands. The below-ground biomass i.e. rhizosphere, can be consistently submerged, serving as a potential source of DOM to the surrounding waters. The lability and possible stimulatory effect of J. roemarianus DOM was examined for three plankton communities collected within the discharge region of Mobile Bay and adjacent waters of Gulf Shores, Alabama (less affected by Mobile Bay). DOM within the pore water surrounding the J. roemarianus was extracted, concentrated, and added to the field communities along with positive (i.e. addition of labile organic matter) and negative (i.e. no additions) controls. In the Mobile Bay experiment, the DOM addition stimulated increased autotrophic biomass and heterotrophic activity well above that observed in the negative controls. However, experiments utilizing Gulf Shores water showed little to no stimulation. Our results suggest that J. roemarianus DOM addition may stimulate planktonic activity; however, the degree of enhancement is likely controlled by the community composition and water properties (e.g. nutrient availability).
Dr. Robert Michael McKay
First Advisor Department
Dr. George Bullerjahn
Second Advisor Department
Dr. Jeffrey Krause
Third Advisor Department
Dr. Behzad Mortazavi
Fourth Advisor Department
Zepernick, Brittany; McKay, Robert Michael; Bullerjahn, George S.; Krause, Jeffrey W.; and Mortazavi, Behzad, "The Influence of Juncus-rhizosphere Dissolved Organic Matter on Coastal Plankton Communities" (2016). Honors Projects. 265.
This is my project's poster that I made for a conference I presented at late summer 2016. Given that I had not begun the research/data analysis phase of the data at BGSU at this point in time, my 2 honors adviser's names are not on this poster copy.
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