Status: this discussion paper is a preprint. It has been under review for the journal Biogeosciences (BG). The manuscript was not accepted for further review after discussion.
The Relationship between Tropical Cyclone Activity, Nutrient Loading, and Algal Blooms over the Great Barrier Reef
Chelsea L. Parker,Amanda H. Lynch,Stephanie A. Spera,and Keith R. Spangler
Abstract. The Great Barrier Reef, the world’s largest coral reef ecosystem, is subject to many environmental stressors. This study utilizes remotely sensed Moderate Resolution Imaging Spectroradiometer (MODIS) chlorophyll a concentration data to explore statistically significant relationships between local-scale tropical cyclone disturbance and relative water quality between 2004–2014. The study reveals that tropical cyclone activity reduces water quality at 8- and 16-day time lags. Relationships suggest that at early stages (during and just after cyclone activity) algal response is induced primarily through wind-driven sediment re-suspension. However, wind speed in isolation only increases minimum levels of chlorophyll a, rather than mean or extreme upper values. At greater time lags (16-day), it is suggested that nutrient runoff from rainfall (and perhaps storm surge) increase phytoplankton activity, leading to detrimental ecological effects. The analyses systematically demonstrate the dominance of tropical cyclone size on mean and extreme values of chlorophyll a during and after tropical cyclone activity (at 0-, 8-, and 16-day time lags). Both the total area affected and the area from which nutrients can be extracted have more impact on chlorophyll a concentrations than either the duration or intensity of the cyclone. Findings indicate that efforts to reduce nutrient and sediment leaching into the reef lagoon from the Queensland coastal lands need to be continued and improved. This will be particularly important in the context of climate change, since tropical cyclone frequency, dynamics and characteristics are likely to change.
How to cite. Parker, C. L., Lynch, A. H., Spera, S. A., and Spangler, K. R.: The Relationship between Tropical Cyclone Activity, Nutrient Loading, and Algal Blooms over the Great Barrier Reef, Biogeosciences Discuss. [preprint], https://doi.org/10.5194/bg-2017-23, 2017.
Received: 27 Jan 2017 – Discussion started: 06 Feb 2017
We use satellite imaging to explore the relationships between tropical cyclones and water quality that is harmful to the Great Barrier Reef. Tropical cyclones reduce water quality 8- and 16-days post-storm where cyclone size is more significant than duration or intensity. Water quality declines first through sediments re-suspended by strong winds, then through rainfall runoff and nutrient loading. Leaching and erosion from coastal land must be reduced, especially with future climate change.
We use satellite imaging to explore the relationships between tropical cyclones and water...