Coral reefs on both the Pacific and Caribbean sides of Panama do not experience extreme weather events such as hurricanes. Coral diversity in Panama is maintained by mechanisms other than extreme weather disturbances, such as predation by the crown-of-thorns seastar, Acanthaster planci.

Note: many invertebrate zoologists insist on the term "sea star" to communicate that invertebrates are not fish. This is similar to the push to move from "jellyfish" to "sea jelly."

Sutherland presents evidence and argues for the existence of "alternative stable states" in several ecosystems—the idea that the history of organisms and physical events in a place can ultimately determine the "final" community. This is opposed to the idea that the community will eventually look the same regardless of which organisms are initially present.

Colonial animals (animals that grow by budding or that live in close association with each other, e.g. the polyps of corals that live together to form a single coral colony) have unique advantages and well as disadvantages compared to solitary organisms.

Jackson's paper describes some of the characteristics of colonial marine organisms, their distributions, and the factors that shape their distributions.

In many ecological systems, there can be more than one "stable, final state" for a community, depending on the history of the community. In a more extreme example, a single, barren part of the ocean floor could end up either a coral-dominated or algae-dominated system depending on a variety of factors including fishing pressure and the first organisms to colonize it.

Rare disturbances like hurricanes could create patches of coral reef that are dominated by different species.

http://onlinelibrary.wiley.com/doi/10.1890/10-0378.1/full

Some species of damselfish cultivate and defend lawns of algae—which serve as a source of food—on dead coral. Damselfish are known for being fiercely territorial and will fight off other species that enter their home territory.

Montastraea annularis (now known as Orbicella annularis) is a species of coral that can grow into boulder-shaped heads. It is commonly known as boulder star coral.

The shape of corals has a strong influence on how much they are damaged because shape directly affects how much force flowing water exerts on the coral's skeleton. Thinly branching corals are especially susceptible to breaking, whereas corals with thicker, leaflike, encrusting, and head forms experience much less mechanical stress during a storm.

Though corals may look like plants, they are actually animals. The basic body form of a coral is called a polyp, which has a mouth surrounded by tentacles. Colonial corals consist of many tiny interconnected polyps.

For a broad overview of the effects of hurricanes on coral reefs, see the following news report from The Guardian: https://www.theguardian.com/environment/2008/jan/24/climatechange

Deep dive: Hurricanes and their Effects on Coral Reefs, a report by the Global Coral Reef Monitoring Network:<br> https://www.coris.noaa.gov/activities/caribbean_rpt/SCRBH2005_03.pdf

Communities in the ocean are often strongly influenced by the physical environment around them, and coral reefs are usually found in clear water. This is why scientists were surprised to discover a coral and sponge reef in the less-than-ideal conditions of the plume of the Amazon river in 2016.

View newly released photos of this reef in National Geographic: http://news.nationalgeographic.com/2017/01/photos-amazon-coral-reef-discovery-research-science/

Read the original article in Science Advances: http://advances.sciencemag.org/content/2/4/e1501252.full

While strong waves and intense pulses of freshwater can cause immediate damage to coral reefs, coral reefs hit by severe tropical storms also experience significant sustained secondary mortality months after the initial impact of tropical storms as a result of less immediate consequences of tropical storms.

This detailed study of survivorship of Acropora cervicornis after Hurricane Allen showed that later mortality was over ten times more severe than the mortality caused by the storm itself and was caused by disease and coral predators feeding on survivors. This complex pattern may explain why rates of recovery from disturbances may vary widely.

“In press” means that the paper had not actually been published at the time.

Connell describes a mechanism by which the high biodiversity of tropical rain forests and coral reefs is maintained by disturbances, contrary to earlier hypotheses that suggested that tropical environments were very stable.

Researchers in Guam describe minimal damage to hard coral reefs after a typhoon and no long-term impact, even in exposed areas. This is likely due in part to the low, rugged profile of reefs in Guam and the fact that they are hit by hurricanes very often.

Many corals sexually reproduce by releasing large numbers of eggs and sperm into the water at once. This requires synchronized timing between multiple colonies and may only happen once a year. Some other corals retain the egg in the parent colony where it is fertilized and then later released.

Corals can also form colonies by asexual reproduction—coral fragments that break off of a parent colony can survive and grow into a new colony. New colonies are also sometimes formed by budding off of existing colonies.

Camouflaged or otherwise hidden (e.g. in a crevice).

Corals compete for space and light with each other as well as other organisms such as algae. Algae have the ability to grow much faster than coral and can quickly overgrow and shade coral if given the chance. Reef herbivores such as the sea urchin Diadema antillarum play an important role in keeping algae at bay, maintaining coral reefs.

A hydrocoral looks like a coral, but is actually in the class Hydrozoa rather than the class Anthozoa, like true corals. Millepora hydrocorals are also known as fire corals due to their painful sting.

Millepora hydrocorals can detect nearby gorgonians and attack them by growing on top of them.

The Mann-Whitney U test is a statistical test used when values are not normally distributed. Here, it is used to compare live tissue coverage before and after the hurricane. The P-value of less than 0.001 indicates that there was a statistically significant difference between the two groups (a P-value of less than 0.05 is commonly accepted as statistically significant under convention).

The fore reef is the ocean-facing section of a reef, seaward of the reef flat.

The flat, shallowest part of a coral reef.

Coral reefs continue to face threats of increasing severity, which could spell disaster if compounded.

Australia's Great Barrier Reef recently experienced its most severe coral bleaching event in history as a result of the combined effects of ocean warming and an El Niño event.

Read more from the Great Barrier Reef Marine Park Authority: http://www.gbrmpa.gov.au/media-room/latest-news/coral-bleaching/2016/the-facts-on-great-barrier-reef-coral-mortality

Making robust ecological conclusions about the effects on an ecosystem of a natural event, such as a hurricane, requires thorough knowledge of that ecosystem both before and after the event.

Because Jamaican coral reefs were well-studied before, during, and after Hurricane Allen, this study is different from previous studies of the effects of hurricanes on coral reef organisms.

Foliaceous means "leafy." Foliaceous corals create thin layers of skeleton that somewhat resemble plant leaves.

Millepora spp. fire corals can live detect gorgonians and will actively grow special "attack" branches towards gorgonians and overgrow them.

In a separate study of corals, small corals were less likely to be injured or damaged, but, when they were, they were much more likely to die.

Communities in the ocean are often strongly influenced by the physical environment around them. This is why scientists were surprised to find a never-before-seen coral and sponge reef in the less-than-ideal conditions of the plume of the Amazon river in 2016.

View newly released photos of this reef in National Geographic: http://news.nationalgeographic.com/2017/01/photos-amazon-coral-reef-discovery-research-science/

Read the original article in Science Advances: http://advances.sciencemag.org/content/2/4/e1501252.full

Coral reefs continue to face threats of increasing severity, which could spell disaster for reefs if compounded. Australia's Great Barrier Reef recently experienced its most severe coral bleaching event in history as a combined result from ocean warming and an El Niño event.

Read more from the Great Barrier Reef Marine Park Authority: http://www.gbrmpa.gov.au/media-room/latest-news/coral-bleaching/2016/the-facts-on-great-barrier-reef-coral-mortality

Since this study was published, hurricanes have been increasing in both frequency and intensity in the North Atlantic. We may begin to see shifts in coral reef communities towards something more like Port Royal.

Read more from the U.S. Global Change Research Program: http://nca2014.globalchange.gov/report/our-changing-climate/changes-hurricanes

Millepora hydrocorals can detect and attack gorgonians by growing on top of them.

Goreau describes the species of corals found in Jamaica's reefs and the patterns of their distributions. He notes that the north and south coasts look different from each and hypothesizes that these differences are driven by differences in storm frequencies.

In many ecological systems, there can be more than one "stable, final state" for a community, depending on the history of the community. In a more extreme example, a single barren part of the ocean floor could end up either coral-dominated or algal-dominated system depending on a variety of factors including fishing pressure and the first organisms to colonize it.

Rare disturbances like hurricanes could create patches of coral reef that are dominated by different species.

http://onlinelibrary.wiley.com/doi/10.1890/10-0378.1/full

the shape and features of the bottom of the ocean

Sea stars from the class Ophiuroidea. Brittle stars are named so for their fragile thin arms.

Swimming together in a group. Schooling behavior provides benefits to individual fish, such as safety in numbers.

camouflaged

Some species of damselfish cultivate and defend lawns on algae, which serve as a source of food, on dead coral. Damselfish are known for being fiercely territorial and will fight off other species that enter their home territory.

The authors measured the degree of damage to certain species of corals, taking care to note the growth form and size. This allowed them to look at how shape and size influenced patterns of damage.

Corals compete for space and light with each other as well as other organisms such as algae. Algae has the ability to grow much faster than coral and can quickly overgrow and shade coral if given the chance. Reef herbivores such as the sea urchin Diadema antillarum play an important role in keeping algae at bay, maintaining coral reefs.

The authors observed injured corals and sponges for several months after Hurricane Allen to see if they survived, noting the initial degree of injury.

The shapes of corals has a strong influence on how much they are damaged because shape directly affects how much force flowing water exerts on the coral's skeleton. Branching corals have large flat exposed areas that are especially susceptible to breaking, while corals with leaf-like, encrusting and head forms experience much less mechanical stress during a storm.

The way that physical forces affected corals depended heavily on their form, since form affects how organisms are influenced by mechanical forces. Different species have different shapes and sizes, so the impact of the storm depends on the species.

The Mann-Whitney U test is a statistical test used when values are not normally distributed. Here it is used to compare live tissue coverage before and after the hurricane. The P-value of less than 0.001 indicates that there was a statistically significant difference between the two groups.

The energy within waves is released most violently in shallow waters. Corals at greater depths were less likely to be damaged.

The authors observed a variety of sites with different profiles both before and after the hurricane. They describe the variation within and between sites here.

Montastrea annularis (now known as Orbicella annularis) is a species of coral that can grow into giant boulder-shaped heads. It is commonly known as boulder star coral.

Connell describes a mechanism by which the high biodiversity of tropical rain forests and coral reefs is maintained by...

Ecological succession is the predictable change in a community over time, usually referring to changes after a disturbance or initial colonization of a habitat.

Corals sexually reproduce by releasing large numbers of eggs and sperm into the water at once. This requires synchronized timing between multiple colonies and may only happen once a year.

Corals can also form colonies by asexual reproduction—coral fragments that break off of a parent colony can survive and grow into a new colony. New colonies are also sometimes formed by budding off of existing colonies.

Various studies describe the aftermath of tropical cyclones on coral reefs. Effects of storms seem to vary depending on the structure, form and composition of the affected reef.

None of the studies cited had intimate knowledge of the impacted reefs immediately before the disturbance.

Corals are a group of colonial marine animals that form hard calcium skeletons. They have stinging cells that can be used to catch and kill small prey but also often carry symbiotic algae inside that they can use to convert sunlight into cellular energy.

When corals live together in large groups, they can form a buildup of sediment and minerals in the ocean called a reef. The complex structures of reefs are habitats for many other ocean animals.

Severe tropical storms can cause widespread mortality in reef corals1,2. The Caribbean staghorn coral, Acropora cervicornis, although dependent on fragmentation for asexual propagation3–5, is particularly vulnerable to hurricane damage6,7. The most important agents of post-hurricane mortality are assumed to be high wave energy6 and change in salinity8, factors which typically soon diminish in intensity. We report here that there was substantial delayed tissue and colony death in A. cervicornis on a Jamaican reef damaged by Hurricane Alien. This previously undocumented degree of secondary mortality, sustained for 5 months and unrelated to emersion9, was over one order of magnitude more severe than that caused by the immediate effects of the storm. The elimination of >98% of the original survivors suggests potentially complex responses to catastrophes, involving disease10,11 and predation, which may explain the widely variable rates of reef recovery previously reported12–15.

Coral reefs on both the Pacific and Caribbean sides of Panama do not experience extreme weather events such as hurricanes. Coral diversity in Panama is maintained by mechanisms other than extreme weather disturbances, such as predation by the crown-of-thorns seastar, Acanthaster planci.

Researchers in Guam describe minimal damage to hard coral reefs after a typhoon and no long-term impact, even in exposed areas. This is likely due in part to the low, rugged profile of reefs in Guam.

Making robust ecological conclusions about the effects of a natural event, such as a hurricane, on an ecosystem requires thorough knowledge of that ecosystem both before and after the event.

Because Jamaican coral reefs were well-studied before, during, and after Hurricane Allen, this study is unique from previous studies of the effects of hurricanes on coral reef organisms.

Because these reefs had been well-surveyed before Hurricane Allen, the authors conducted surveys using the same methods after the hurricane to examine the impacts of the storm.

The authors noted damage to corals after the hurricane and tracked their subsequent recovery (or death).

Hurricanes hit the southern coast of Jamaica more often than the northern coast, and scientists have previously thought that this may be the reason for the observed differences in coral communities.

Differences include larger areas of dead coral and lower population densities of corals in certain reef zones on the southern coast.

Disturbances in the environment, such as storms and fires, can affect the state of an ecological community.

For example, traditional ecological knowledge dictates that when disturbance is very frequent or intense, all species in the affected area may become locally extinct—but when disturbance is very rare, the community may become dominated by only the most competitive species. An intermediate level of disturbance may, counterintuitively, maintain the highest level of biodiversity.

Polychaetes are a diverse group of worms. Polychaetes are commonly found at the bottom of the ocean and are an important part of marine food webs.

uneven, with some spots being affected more than others

Acropora palmata is commonly known as Elkhorn coral for its antler-like appearance. As a result of its complex 3-d shape, Acropora palmata adds significant structure to coral reefs and forms an important habitat for many other marine organisms.

The substratum is the underlying layer of rock or sediment. This refers to the surface that the corals attach to.

Gorgonians are part of a group of corals often called "soft corals" due to their lack of a rigid calcified skeleton. Arborescent means "tree-like," referring to gorgonians that specifically have upright tree-like forms.

Fecundity refers to the ability for an organism to produce offspring. If an organism is more fecund, this means it produces more offspring.

Recruitment refers to the successful addition of new individuals to a population.

The demersal zone is the layer of water nearest to the bottom of the ocean. Plankton are tiny microscopic organisms that live in the water column.

Motile organisms are organisms that can move around, such as shrimp or fish. Sessile organisms, like corals, do not move for the majority of their lives.

A hydrocoral looks like a coral, but is actually in the class Hydrozoa rather than the class Anthozoa, like true corals. Millepora hydrocorals are also known as fire coral due to their painful sting.

Encrusting animals form a thin layer (i.e. a "crust") over another hard surface.

While corals may look more like plants than animals, corals are actually a colony of many tiny animals living together. Each "individual" animal is called a polyp.

Foliaceous means "leafy." Foliaceous corals create multiple thin layers that somewhat resemble plant leaves.

Diadema antillarum is commonly known as the long-spined sea urchin. Before populations of Diadema antillarum died off in 1983 in massive numbers, they were a common sight in Caribbean reefs and played an important role in controlling the growth of macroalgae.

The fore reef is the ocean-facing section of a reef.

Agaricia is a genus of corals that form flat leaf-like or plate-like structures. The "spp." means "multiple species of." So Agaricia spp. means "species of the genus Agaricia."

The flat part of a coral reef, closer to shore.

As ocean waves move towards shallower waters, they eventually become unstable and break. A breaker zone is a region where waves begin breaking.

Taxonomy is the science of describing, identifying and classifying species. Taxonomic differences, in this context, are differences in the species present.

A community is a group of interacting organisms that live in the same location. Community composition is the makeup of a community

When natural events (i.e. fires, hurricanes or other disturbances) happen to only some areas, scientists can study the effects by comparing affected and unaffected sites. This is a natural experiment.