'Bleaching' on sea_env ? ; coral bleaching ; Bleaching Alert level

 

 

 

What is coral bleaching?

When corals are stressed by changes in conditions 
such as temperature, light, or nutrients,

they expel the symbiotic algae living in their tissues,

causing them to turn completely white.

https://oceanservice.noaa.gov/facts/coral_bleach.html

What is coral bleaching?

 

 

 

Overexposure to sunlight When temperatures are high, high solar irradiance contributes to bleaching in shallow-water corals. Extreme low tides Exposure to the air during extreme low tides can cause bleaching in shallow corals. NOAA’s Coral Reef Conservation Program.

 

 

https://oceanservice.noaa.gov/facts/coralreef-climate.html#:%7E:text=Climate%20change%20leads%20to%3A,to%20the%20smothering%20of%20coral.

How does climate change affect coral reefs?

 

 

 

http://oceanportal.spc.int/portal/help/about_coralbleaching.pdf

Bleaching Alert level ?

 

 

Bleaching Alert: Defined in the table below, the bleaching alert levels are based on current values of the coral bleaching HotSpot and Degree Heating Weeks (DHW) products. HotSpot is defined as the positive difference between the satellite-observed SST and the climatologically averaged temperature for the warmest month at that pixel. Degree Heating Weeks is the accumulated thermal stress, and is calculated as the sum of all values of HotSpot ≥ 1ºC during the past 12-week period at that pixel. In the Bleaching Alert Area product every pixel has an alert level defined and is color-coded (see Table 1). The alert reflects the maximum thermal stress experienced in the prior seven days. The data are at 0.05 degree (5 km) resolution, updated daily. 

 

 

 

A status level of "Bleaching Watch" means that there is low-level thermal stress present at that location but not of sufficient magnitude to accumulate stress for corals, should they exist in that location. Previous thermal stress exposure may still have adverse impacts on the corals, although recovery may be underway. If SST at a location exceeds the bleaching threshold (maximum monthly mean climatology + 1ºC, = HotSpot of 1C) then a bleaching warning is issued. Alert Level 1 indicates that DHW has reached 4ºC-weeks and coral bleaching is likely to occur for some coral species. Alert Level 2 indicates DHW has reached 8ºC-weeks and both widespread bleaching and significant coral mortality are likely. The bleaching intensities given are representative of ecosystem impacts for most coral reef communities. Coral species more susceptible to thermal stress may experience bleaching during a Bleaching Warning, while resistant species may only bleach during Alert Level 2. A worked example of the bleaching alert calculation for one pixel location is show in Table 2.

 

 

 

 

 

https://blog.naver.com/chae990515/222505652361

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