What Can I Do?

With all this talk about the hurricanes destroying corals you may be wondering (I hope), “But what can little old me do to stop such a monstrous creation?”

You may think it impossible but action can be taken to protect our reefs. Of course you can't physically, directly stop a hurricane, but rather inadvertently reduce the effects of it.

By simply planting a tree, you reduce the amount of carbon dioxide in the air, which reduced global warming and thus the rise in ocean temperature.

Carpool to destinations so that less carbon dioxide is produced by the engines, or even using public transport.

Picking up rubbish or not littering can reduce the amount of pollution in the sea. When you properly dispose of your litter, they don't enter darain and oceans which can get stuck on coral or damage it due to the force of waves.

Photo Credit: Kathryn Berry

If you're in the Caribbean, avoid stepping/ touching the coral reefs when diving. And DO NOT break off pieces as souvenirs.

Also avoid using products such as sunscreens that contain Benzophenone-2 as it was found to stop coral reproduction [1]

By preserving red mangrove trees (Rhizophora mangle), the most common type found in the Caribbean, the amount of litter entering the sea can be reduced. These trees are found in swamps, or brackish water (mixture of salt and fresh water) along coastlines, with long roots that act as a filter for rubbish and litter and as a means of preventing coastal erosion. It also creates an area for fresh water to mix with the sea so there would not be a drastic salinity change. The large area the trees occupy also cools down the water when they block the sun. [2]

Photo Credit: Emma Camp

To find out what further action you can take visit:

https://www.epa.gov/coral-reefs/what-you-can-do-help-protect-coral-reefs

Reference:

[1]http://www.haereticus-lab.org/wp-content/uploads/2015/10/ecotox-sunscreen-chemicals.pdf

[2]https://news.nationalgeographic.com/news/2015/02/150210-mangrove-protect-coral-bleaching-science/

A Hurricane's Purpose

Many see hurricanes as only destructive forces of nature that reck property, ruin crops and overall destroy 

livelihoods. The task of rebuilding is always a long and challenging one, be it a human community or wildlife. But there is always some good in the bad, as nature has a way of balancing everything.

Believe it or not hurricanes actually help corals around its vicinity by reducing the Earth’s temperature. 

According to the article “Hurricanes and their Effects on Coral Reefs” published by the Global Coral Reef 

Monitoring Network, there are three ways in which hurricanes can do this [1]. They are:

1) Hurricanes use heat as an energy source. As stated in a previous post, hurricanes need certain conditions to form, one being warm waters. They take up heat from the upper water column and surface water through latent heat of vapourization, where energy is absorbed to change its physical state while maintaining it temperature.[2]. The heat energy absorbed, fuels the hurricane, while the energy lost from the ocean, cools it.

Image Credit: Yiqi Shao

2)Turbulent waves bring up cooler water. The massive disturbance that a hurricane creates can change the sea surface temperature, which is the temperature of the ocean’s surface millimeter [3]. The wind created by the hurricane turns the water creating waves, which can turn the water, bringing cooler water to the surface. This mixing of temperatures, reduces the sea surface temperature. Of course the extent of this depends on the wind speed and depth of ocean.

Image Credit: EOSC 114

3)Clouds shade the ocean from the sun. The cloud of a hurricane can stretch for miles, covering a significant portion of the Earth. This cloud cover prevents the Sun’s UV light from reaching the ocean’s surface. This gives the water a chance to cool by releasing heat into the atmosphere. The clouds also reflect the sunlight back out into space so the atmosphere cools as well [4].  

Photo Credit: NASA Satelites 

Image Credit: NASA ClimateKids

Once the temperature of the water is decreased, it removes thermal stress from the coral, stopping coral 

bleaching [5]

Next time you wonder why something as destructive as a hurricane existe, imagine if hurricanes were not 

here to regulate ocean temperature. The seas would boil. All the coral in the tropics would begin bleaching, 

and eventually die. Many reef species would be left without shelter or food, leading to the extinction of some 

species. This would then cause a collapse in the marine food web and the starvation of millions of people 

who depend on the ocean for food. Not to mention, if oceans ever reach their limit of heat absorption, it 

would remain trapped in the atmosphere, slowly baking the Earth.

References:

[1] HURRICANES, BACKGROUND TO. “3 Hurricanes and their effects on coral reefs.” Status of 

Caribbean coral reefs after bleaching and hurricanes in 2005 31 (2008).

https://cmsdata.iucn.org/downloads/status_carib_corals.pdf#page=39

[2] https://www.britannica.com/science/latent-heat

[3] https://earthobservatory.nasa.gov/global-maps/MYD28M

[4] https://climatekids.nasa.gov/review/greenhouse-effect/clouds-cool.html [5]https://coralreefwatch.noaa.gov/satellite/bleachingoutlook/descriptions/demo_background_stress.php

How Hurricanes Attack the Reef

Hurricanes are forces of nature that cause destruction wherever they go. In an earlier post, the effect of  

hurricanes on land were discussed, but now we focus on the actually point of this blog, their effects on coral 

reefs.

When a hurricane approaches land the force of the wind and sea push water unto to the land in what is 

known as a “storm surge”. This water can erode the land near the sea and change the mineral content of the soil. The effects of storm surges on land can be reduced by coral reefs [1]. The coral act as a 

surf break, where the force of the waves is dissipated when the water has to flow against/around the structures. This reduces the energy the wave possesses so that the height and inland intrusion would be reduced.

Image Credit: The Pew Charitable Trusts

According to the article “ Hurricanes and their effect on coral reefs” by the Global Coral Reef Monitoring 

Network, the force of the waves can often be too strong for the corals to withstand so branches and whole 

coral colonies are broken or uprooted from the reef. This can further add to the destruction when these loose pieces are picked up by the wave and thrown against the reef. In the Caribbean, mainly branching elkhorn (Acropora palmata) and staghorn (Acropora cervicornis) coral are broken by intense wave action. Whole tubular colonies are often broken at the base, where it then acts like a wrecking ball on the other coral. [2]

Photo Credit: ESI

The article further went on to say that, the rolling motion of the wave also picks up sand and other debris 

from the ocean floor, carrying it with the waves. The heavier particles containing sand and nutrients, would 

settle on corals causing algae growth [3]. This can be further aided by agricultural runoff, where nutrients from fertilizers are washed into the sea enriching the water with minerals needed to help the algae grow. The algae rapidly grows over the coral surface smothering it, blocking nutrients, oxygen and light, eventually killing the coral [4]. The lighter particles can remain suspended turning the water opaque. This can prevent light from reaching the remaining coral, stopping zooxanthellae (organisms that share a mutualistic symbiotic relationship with the polyps) from photosynthesising. This reduces the amount of oxygen the coral receives, which suffocates it.[5]

Photo Credit: Reef Assessment Monitoring Program

Hurricanes also bring large amounts of rainfall. This addition of fresh water to the environment may be good for land plants but it has devastating effects on marine life. The large quantity of  fresh water added to the sea changes the salinity of the water [6]. This reduction of salt content causes the osmotic pressure in corals to change. More fresh water is taken in creating stress on the corals. [7]

This stress in turn can causes mass coral bleaching. The mechanical damage and chemical composition of the water affects the coral so much they release all their zooxanthellae (microorganisms that give corals their characteristic colour) turning them white. They do this in an effort to recover but if the damage is to severe the zooxanthellae will not be accepted back and the polyp will eventually died. [8]

References:

[1]https://blog.nature.org/conservancy/2011/12/08/coral-reef-wave-break-attenuation-mike-beck/

[2]https://ambergriscaye.com/reefbriefs/briefs31.html

[3]https://link-springer-com.ezproxygateway.sastudents.uwi.tt/article/10.1007/s003380000129

[4]https://www.sbs.com.au/topics/science/nature/article/2016/04/27/weakened-coral-reefs-are-facing-

threat-algae-colonisation

[5]HURRICANES, BACKGROUND TO, “3. Hurricanes and their effects on coral reefs.” Status of 

Caribbean coral reefs after bleaching and hurricanes in 2005 31 (2008)

https://cmsdata.iucn.org/downloads/status_carib_corals.pdf#page=39

[6]Jackson, J. B. C., M. K. Donovan, K. L. Cramer, and V. V. Lam. “Status and trends of Caribbean coral 

reefs.” Gland: Global Coral Reef Monitoring Network, IUCN.

https://www.researchgate.net/profile/Sara_Rivero-

Calle/publication/272611622_GCRMN_Caribbean_report_Status_and_Trends_of_Caribbean_Coral_Reef

s_1970-2012_Puerto_Rico_Chapter/links/55195fa60cf2d241f3564ae4/GCRMN-Caribbean-report-

Status-and-Trends-of-Caribbean-Coral-Reefs-1970-2012-Puerto-Rico-Chapter.pdf

[7]http://www.reefresilience.org/coral-reefs/stressors/climate-and-ocean-change/changes-in-storm-

patterns/

[8]https://oceanservice.noaa.gov/education/kits/corals/coral08_naturalthreats.html