Using NOAA Satellite Data to Keep Watch on Coral Reefs PDF files for this presentation, more data activities (and the answer sheet!) are found on our website: https://coralreefwatch.noaa.gov/satellite/education/index.php Modified by Kristine Grayson, University of Richmond

Corals live in symbiosis with algae Stress Corals release their algae For more on coral bleaching: https://coralreefwatch.noaa.gov/satellite/education/tutorial/welcome.php Also see this great video: http://www.hhmi.org/biointeractive/coral-bleaching

Causes of Coral Bleaching Many local problems can cause bleaching: Freshwater from floods Pollution Disease Sediment Cyanide fishing

Temperature When the water gets hot and stays hot, corals will bleach Causes of Coral Bleaching But only one thing causes bleaching at a Regional or Global scale Temperature When the water gets hot and stays hot, corals will bleach

Thermal Stress Causes Mass Coral Bleaching Geographically widespread coral bleaching was first reported from the SE Tropical Pacific Since then several major coral bleaching events have occurred in 1987/88, 1990/91, 1994/95, 1997/98, 2001/02, 2005… Coral bleaching has been reported from all of the tropical seas and some areas have bleached repeatedly. Now recognised as one of the most significant global threat to coral reefs Coral bleaching does not discriminate between ‘pristine’ and impacted area

Thermal Stress Causes Mass Coral Bleaching

Thermal Stress Causes Mass Coral Bleaching and Mortality

What are the consequences? Environmental impacts Loss of coral Changes in reef community Loss of biodiversity Economic impacts Decreased tourism appeal Fishery decline Loss of ecosystem “services” Subsistence fishing Recreation Cultural significance Shoreline protection

Using Satellite Sea Surface Temperature to Predict Coral Bleaching Have students go here and explore http://coralreefwatch.noaa.gov/satellite/vs/

What satellites do we use? NOAA’s polar-orbiting POES satellites view most of the earth’s surface every day. Animation from the COMET Program (http://www.comet.ucar.edu/)

How do we measure the temperature of the ocean from 850km above the surface? If you stand next to a fire, you can feel the heat on your skin. Satellite uses this infrared radiation to “feel” how warm the ocean is.

Sea Surface Temperature Anomaly Put today’s map here! This is an example of the global SST anomaly product from Coral Reef Watch. Blue to purple colors mean that the current SST is below the long-term average for that day and in that location; yellow to red means the SST is above average. https://coralreefwatch.noaa.gov/satellite/vs/ Click SST Is today’s temperature above or below average for this location at this time of year?

Bleaching Threshold Temp Maximum monthly mean: Average temperature for the warmest month Bleaching Threshold (Defines a Hot Spot): One degree above Maximum Monthly Mean (MMM + 1°C) Varies with latitude and local conditions: Gulf of Oman: 33.5° Florida Keys: 30.3° Oahu, Hawaii: 28.0° Galapagos: 27.5° The concept for a bleaching threshold temperature was introduced in 1990 as one degree above the summertime maximum temperature. Coral Reef Watch define the summertime maximum temperature as being the maximum of the monthly mean temperatures. https://coralreefwatch.noaa.gov/satellite/education/tutorial/crw22_bleachingthreshold.php

Is today’s temperature above the average Coral Bleaching HotSpots Put today’s map here! An example of a HotSpot chart. Areas in white indicate that the current SST is below the MMM. Areas in the shades of purple are above MMM, but still less than one. Any areas in orange to red are above the bleaching threshold temperature, defined as MMM + 1. More info: Is today’s temperature above the average for the warmest month?

Degree Heating Weeks (DHW) Put today’s map here! An example of the Degree Heating Week chart. The units are “°C-weeks”, combining temperature and time into one measure of thermal stress. How much thermal stress has built up over the past three months?

Degree Heating Weeks (DHW) Temperature and duration combined: °C – weeks 10 DHWs could be: 1 degree above MMM for 10 weeks 2 degrees above for 5 weeks 0.5 degrees above for 20 weeks How much thermal stress has built up over the past three months?

Use of DHW to predict coral bleaching DHW = 0 No Thermal Stress DHW >= 4 Thermal Stress leading to significant bleaching DHW >= 8 Thermal Stress leading to wide spread bleaching and significant mortality Accumulated thermal stress, represented by the Degree Heating Weeks product, is the best indication of coral bleaching risk. If DHWs are zero, there has been no thermal stress in the region over the last 3 months. If DHWs rise above 4, the area is likely to see significant coral bleaching. DHWs above 8 can cause widespread bleaching, and some coral mortality may occur.

Coral Bleaching Alerts What areas are currently vulnerable?

Examine the Data Divide into four groups: Bermuda U.S. Virgin Islands Puerto Rico Bahamas Examine temperatures leading up to the 2005 Caribbean bleaching event

Long-term Temp Trends

Implications Today

SST  Hotspots  DHW STOP HERE TO DO MODULE

NOAA Product

How bad was the 2005 Bleaching? These data come from local researchers throughout the Caribbean and Guld of Mexico region. Remember that this is not based on satellite data now– these are researchers actually swimming around on the reef and measuring how much of the coral bleached.

How bad was the 2005 Bleaching? > 1500 on-site surveys These data come from local researchers throughout the Caribbean and Guld of Mexico region. Remember that this is not based on satellite data now– these are researchers actually swimming around on the reef and measuring how much of the coral bleached. Each dot represents the average percentage of the coral colonies that were bleached at that location.

How bad was the 2005 Bleaching?

How bad was the 2005 Bleaching? Bleaching surveys from the four sites

How bad was the 2005 Bleaching? Bleaching surveys from the four sites Bleaching was worst in the US Virgin Islands Puerto Rico and Lee Stocking Island were statistically identical Bermuda < 1% of coral colonies bleached.

Are there signs of hope for bleaching? This reef in Palau was devastated by bleaching in 1998. Ten years later, the reef is covered with healthy corals. If conditions are favorable, reefs can recover: good water quality low fishing pressure many grazing fish low nutrient pollution Coral bleaching can be a depressing topic to think about, especially when we talk about climate change. These slides give some signs of hope, and explain why we don’t give up on coral reefs altogether. Image from Peter Mumby, University of Exeter (more at http://www.reefvid.org/)

Are there signs of hope for bleaching? Local managers can: Reduce bleaching Reduce light stress Cool reefs, increase mixing Increase survival Improve water quality Reduce disease prevalence Aid recovery Coral fragmentation Encourage recruitment Protect ecosystem functions (herbivory)

Are there signs of hope for bleaching? After bleaching and death of corals…. Sensitive coral species are killed…. The corals that remain are the ones that can tolerate higher temperatures. Result? Less diversity, but the reef as a whole develops bleaching resistance.

Are there signs of hope for bleaching? Some places are heating more slowly than others These regions may act as natural refuges where coral reefs may survive. A recent article on this topic: Kleypas, J. A., G. Danabasoglu, and J. M. Lough Potential role of the ocean thermostat in determining regional differences in coral reef bleaching events Geophysical Research Letters, vol. 35 9 February 2008