Ocean Acidification and Hypoxia: Double Trouble for Tubeworms?
Mukherjee, J., Wong, K.K.W., Chandramouli, K.H., Qian, P.-Y., Leung, P.T.Y., Wu, R.S.S. and Thiyagarajan, V. 2013. Proteomic response of marine invertebrate larvae to ocean acidification and hypoxia during metamorphosis and calcification. The Journal of Experimental Biology 216: 4580-4589.
Concurrently, they also note that "anthropogenic activities such as the discharge of excessive nutrients, sewage and agricultural fertilizers are causing coastal waters to become increasingly nutrient rich (Howarth et al., 2011)," such that they sustain increases in algal production to the point that "this excessively produced biomass eventually decomposes, resulting in dead zones, areas of hypoxia that have become deprived of dissolved oxygen," citing Ekau et al. (2010) and Rabalais et al. (2010) in this regard. And they thus make the point that as time marches on and these conditions worsen, "the ability of larvae to successfully metamorphose and build their calcareous tubes is likely to be compromised as a direct consequence of the combined effect of OA and hypoxia."
In a test of this hypothesis, Mukherjee et al. set out to investigate "the proteomic response of metamorphosing larvae of the tubeworm Hydroides elegans, challenged with two climate change stressors, ocean acidification (pH 7.6) and hypoxia (2.8 mg O2 per liter)," as well as with both of the stressors combined. The seven scientists report that concomitant exposure to the two climate change stressors "caused several proteins involved in energy metabolism, calcification and stress tolerance to be differentially expressed." And they say that this phenomenon "seemed to allow the tubeworm larvae to successfully metamorphose and carry out calcification." As a result of their findings, Mukherjee et al. concluded that "the aragonite tube-forming tubeworm larvae have a high tolerance to hypoxia and may possess the capacity to acclimate over time, even in the phase of ocean acidification."
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