coral reef subject review

Coral organisms are composed of hundreds to hundreds of thousands of individual animals called __________.

polyps

The mouth of individual coral animals is surrounded by a circle of __________.

tentacles

After food is consumed by corals, waste products are expelled through the __________.

mouth

The time of day when most corals feed is __________.

night

To capture their food, corals use stinging cells called __________.

nematocysts

Nematocysts are capable of delivering powerful, often lethal, __________.

toxins

A coral’s prey ranges in size from nearly microscopic animals called __________.

zooplankton

Many corals collect fine organic particles in films and strands of __________.

mucous

Most reef-building corals contain photosynthetic algae called __________.

zooxanthellae

Corals and algae have a __________ relationship.

symbiotic

Symbiotic algae supply corals with glucose, glycerol, and amino acids, which are the products of __________.

photosynthesis

Tropical ocean waters are generally __________ in nutrients.

poor

The relationship between the algae and coral polyp facilitates a tight __________ of nutrients.

recycling

The unique and beautiful colors of many stony corals are caused by __________.

zooxanthellae

__________ can cause coral polyps to expel their algal cells.

physical stress

Coral __________ occurs when coral polyps expel their algal cells, causing the colony to appear stark white.

bleaching

Because of their intimate relationship with symbiotic __________, reef-building corals respond to environmental changes like __________.

plants

Because their algal cells need light for photosynthesis, reef corals require __________ water.

nutrient poor

Although coral reefs require nutrient-poor water, they are among the most __________ and diverse marine environments.

productive

Reefs form when polyps secrete skeletons of __________.

calcium carbonate

As they grow, coral reefs provide structural __________ for hundreds to thousands of different species.

habitat

The skeletons of stony corals are secreted by the lower portion of the polyp and produces a cup, or __________, in which the polyp sits.

calyx

The walls surrounding the corals’ skeletal cup are called the __________.

theca

The floor of the corals’ skeletal cup is called the __________.

basal plate

CBMS is a system of specially designed buoys that measure conditions that may cause __________ on coral reefs.

bleaching

When polyps are physically stressed, they contract into their calyx to expose little of their body and usually extend the farthest when they __________.

feed

__________ corals have primary and secondary branches.

branching

__________ corals look like fingers or clumps of cigars and have no secondary branches.

digitate

__________ corals form table-like structures and often have fused branches.

Table

__________ coral has large, flattened branches.

Elkhorn

__________ corals have broad plate-like portions rising in whorl-like patterns.

Foliose

__________ corals grow as a thin layer against a substrate.

Encrusting

__________ corals are ball-shaped or boulder-like and may be small as an egg or as large as a house.

Massive

__________ corals resemble the attached or unattached tops of mushrooms.

Mushrooms

Coral reefs begin to form when free-swimming coral __________ attach to submerged rocks or other hard surfaces along the edges of islands or continents.

larvae

__________ reefs project seaward directly from the shore, forming borders along the shoreline and surrounding islands.

Fringing

__________ reefs border shorelines, but are separated from their adjacent land mass by a lagoon of open, often deep water.

Barrier

An __________ is formed when a reef develops around a volcanic island that subsides completely below sea level while the coral continues to grow upward.

Atoll

Massive corals have growth rates of __________ per year.

0.3 to 2 centimeters

Bottom topography, depth, wave and current strength, light, temperature, and suspended sediments act on coral reefs to create __________ of living species.

horizontal and vertical zones

The reef __________ is usually the zone closest to shore.

flat

The reef __________ or algal ridge follows the flat zone.

crest

The __________ zone follows the reef crest, and finally the seaward slope.

buttress

Reef-building corals cannot tolerate water temperatures __________ 18° Celsius.

below

Most reef-building corals require very __________ water.

salty

Reef-building corals’ requirement for high light explains why most reef-building species are restricted to the __________ zone.

epipelagic

As adults, almost all corals are __________, which means they remain on the same spot on the sea floor.

benthic

In __________ reproduction, new polyps bud off from parent polyps to expand or begin new colonies.

asexual

In sexual reproduction, coral eggs and sperm join to form free-floating larvae called __________.

planulae

Species that release massive numbers of eggs and sperm into the water are called __________ spawners.

broadcast

The time between planulae formation and settlement is a period of exceptionally high __________ among corals.

mortality

Along many reefs, spawning occurs as a __________ event when all species in an area release their eggs and sperm at about the same time.

synchronized

The long-term control of spawning may be related to temperature, day length, and/or rate of temperature change. The short-term control is usually based on __________ cues.

lunar

The final release of gametes during spawning is usually based on the time of __________.

sunset

Planulae exhibit positive __________.

phototaxis

Once planulae settle on the bottom, they __________ into polyps and form colonies.

metamorphose

Coral reefs support more __________ per unit area than any other marine environment.

species

Scientists estimate that there may be __________ of undiscovered species of organisms living in and around reefs.

millions

Coral reef biodiversity is considered key to finding new __________ for the 21st century.

medicines

Healthy reefs contribute to local economies through __________.

tourism

In developing countries, coral reefs provide critical __________ resources for tens of millions of people.

resources

Coral reefs buffer adjacent shorelines from wave action and prevent __________, property damage, and loss of life.

erosion

Natural damage to coral reefs frequently occurs because of __________.

weather

Slow-growing corals that are damaged by storms may be overgrown by __________ before they can recover.

algae

Reefs are also threatened by __________ that can cause shallow water coral heads to overheat and dry out.

low tides

Increased sea surface temperatures, decreased sea level, and increased salinity can all result from weather patterns such as __________.

El nino

Corals are vulnerable to __________ by fishes, marine worms, barnacles, crabs, snails, and sea stars.

predation

Human-caused, or __________ activities are major threats to coral reefs.

anthropogenic

One of the most significant human-caused threats to reefs is __________.

pollution

When some contaminants enter the water, nutrient levels can increase, promoting the rapid growth of __________ and other organisms that can smother corals.

algae

In many areas, coral reefs are destroyed when cyanide or dynamite are used for __________ activities.

fishing

Coral diseases generally occur in response to biological __________, such as bacteria, fungi, and viruses, and nonbiological stresses.

stressors

Many scientists believe that the increased frequency of coral diseases over the last 10 years is related to deteriorating water quality and increased __________.

temperatures