The effects of El Niño‐Southern Oscillation events on intertidal seagrass beds over a long‐term timescale |
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| Authors: | Hsing‐Juh Lin Chen‐Lu Lee Shang‐En Peng Meng‐Chi Hung Pi‐Jen Liu Anderson B. Mayfield |
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| Affiliation: | 1. Department of Life Sciences and Innovation and Development Center of Sustainable Agriculture, National Chung Hsing University, Taichung, Taiwan;2. Biodiversity Research Center, Academia Sinica, Taipei, Taiwan;3. Endemic Species Research Institute, Nantou, Taiwan;4. Graduate Institute of Marine Biology, National Dong Hwa University, Pingtung, Taiwan;5. National Museum of Marine Biology and Aquarium, Pingtung, Taiwan;6. Khaled bin Sultan Living Oceans Foundation, Annapolis, Maryland |
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| Abstract: | El Niño‐Southern Oscillation (ENSO) events can cause dramatic changes in marine communities. However, we know little as to how ENSO events affect tropical seagrass beds over decadal timescales. Therefore, a diverse array of seagrass (Thalassia hemprichii) habitat types were surveyed once every 3 months for 16 years (January 2001 to February 2017) in a tropical intertidal zone that is regularly affected by both ENSO events and anthropogenic nutrient enrichment. La Niña and El Niño events had distinct effects on the biomass and growth of T. hemprichii. During La Niña years, higher (a) precipitation levels and (b) seawater nitrogen concentrations led to increases in seagrass leaf productivity, canopy height, and biomass. However, the latter simultaneously stimulated the growth of periphyton on seagrass leaves; this led to decreases in seagrass cover and shoot density. More frequent La Niña events could, then, eventually lead to either a decline in intertidal seagrass beds or a shift to another, less drought‐resistant seagrass species in those regions already characterized by eutrophication due to local anthropogenic activity. |
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| Keywords: | ENSO eutrophication
Halodule uninervis
La Niñ a periphyton
Thalassia hemprichii
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