Weida Gong’s Research

Weida_RAPlotHarmful algal blooms (HABs) have become a major nuisance in many estuarine and coastal marine systems worldwide. Toxins produced by some HABs may be detrimental to fish, birds, marine mammals and even humans. Just as important, blooms of nontoxic microalgae resulting in bottom-water hypoxia are detrimental and potentially fatal to sessile macrofauna. In marine habitats heavily impacted by human activities, efforts have been made to prevent conditions that promote HABs.  However, progress is limited due to an incomplete understanding of the environmental and cellular processes that promote and propagate these blooms. The complexity of natural blooms in the  environment makes it difficult to simulate in lab. In order to understand the in situ metabolic activities of blooming microalgae, analysis of natural blooms needs to be conducted.  I am interested in how we can use molecular techniques along with  bioinformatic approaches  to reveal the nature of HABs, and how we can utilize the results of molecular analysis to make more effective management plans to better control algal blooms.

A dinoflagellate bloom was reported in the Neuse River Estuary, NC on Sep 26th, 2012 and we obtained samples at the bloom station as well as two non-bloom stations. We conducted a metatranscriptomic study on the samples and investigated how dinoflagellates were regulating their metabolic pathways to respond to their environment.

Our results show that the blooming dinoflagellates had high metabolic rates, with increased photosynthesis and carbon fixation activity to support an elevated energy demand. In addition, metabolic signals of nutrients scavenging in the blooming dinoflagellates were detected, indicative of nutrient shortages in the environment due to high dinoflagellate abundance and high nutrient consumption. To cope with the environmental stress, based on gene expression analysis, dinoflagellates appeared to be biosynthesizing and exporting massive amount of carbohydrates to feed surrounding bacteria in possible exchange for nutrients and vitamins (e.g. ammonium, B12) produced by bacterial remineralization. We hypothesize that these microbial  interactions are essential to the prolongation of algal bloom events.