Substrate ID Training Global Community Coral Reef Monitoring Program

Substrate ID Training

Global Community Coral Reef

Monitoring Program

Coral reefs are typified by large hard corals that build the reef structure and support a myriad of life.

They are tropical ecosystems that rival only rainforests in biodiversity and are important to us for:

What is a coral reef?

• Food;

• Shore breaks;

• Pharmaceuticals;

• Tourism.

Low nutrient, clear water;

Sunlight;

Salinity around 30 – 36 ppm;

Water temperature between 20 - 29ºC;

More effective management than is currently in place.

What conditions do reefs require?

Naturally subject to environmental disturbance, the health of a coral reef can be measured in terms of its resilience to impacts and its ability to recover from disturbance. We can measure this health by monitoring how they change over time.

As the disturbance – recovery regime of a coral reef is complex, the longer time-period we have monitoring data for, the more patterns we can see. Therefore, by monitoring the reef each year from now, we’ll be really helping scientists understand how the reef works in the future.

The Reef Check Substrate Categories

HC – HARD CORAL (includes blue coral, fire coral and organ pipe coral)*HCB – BLEACHED HARD CORALSC – SOFT CORAL (includes zoanthids)*SCB – BLEACHED SOFT CORALNIA – NUTRIENT INDICATOR ALGAE (includes seaweed that proliferates

with high nutrient input. *Record what it is on top of e.g. NIA/RC)

OT – OTHER (includes other living or non-living substrata, such as, hydroids, anemones, gorgonians and ascidians)

SP – SPONGERC – ROCK (includes any surface that coral could settle onto including

rock covered with turf algae, bivalves, coralline algae and dead coral)

RKC – RECENTLY KILLED CORAL (includes coral that has died in the last year. Such coral will still have a white or partially white skeleton and may be slightly overgrown with algae. *If it

has NIA on top of it then write NIA/RKC)RB – RUBBLE (includes dead coral of 0.5 to 15 cm diameter)SI – SILT (write the substrate underneath e.g. SI/RC)SD – SAND (includes pieces less than 0.5 cm in diameter)

*This only applies to Reef Check Queensland, Australia.

HARD CORAL The reef builders

Reef Check code: HC

HARD CORALThe reef-builders

Hard corals function as the main builders of coral reefs. They are also important in providing both food and shelter to a large number of reef organisms.

Coral reefs are naturally subjected to erosion from wave surges and boring organisms. As hard corals lay down more of their underlying limestone or calcium carbonate skeleton the reef grows.

When there is a mass hard coral die-off on a reef from a storm, crown-of-thorns starfish outburst or other impact, the reef itself loses its ability to ‘grow’ and may be eroded down. Additionally, the organisms reliant upon the hard coral structures for hiding from predators will likely decrease in abundance as their habitat is lost.

Hard coral includes:

• All hard corals;

• Fire coral (Millepora);

• Blue coral (Heliopora);

• Organ pipe coral (Tubipora musica).


MouthWhere food is ingested and waste excreted.

Stomach.

Cross section through a coral polyp

Limestone skeleton that is excreted by the coral polyp. This skeleton ‘builds’ the reefs.

Coral cup or ‘corallite’.

Tentacles for catching food using stinging cells (nematocysts) to stun their prey. Hard coral polyps have 6 or multiples of 6 tentacles.

Zooxanthellae algae live in the coral’s tissue and make food from sunlight using photosynthesis. This food counts for 90+% of the coral’s food.

Mucus is excreted from the coral’s surface, which provides a limited ability to clean itself from sediment.


Most corals, as well as many other similar coral reef organisms, are colonial. This means that individual animals, like coral polyps, are joined to one another by a thin layer of cells called tissue. Animals on the same colony are typically identical genetically as they are formed by asexual reproduction. Corals also reproduce sexually once or twice a year (coral spawning) and the young corals (recruits) will settle on the reef and start a new colony. By joining one another, they can share food as well as send messages to one another, for example, a message to close up if there is danger.


Coral Growth Forms

Corals can grow in may different shapes. For the purpose of Reef Check, we are not interested to record the different shapes of hard coral that we see. Therefore, do not attempt to learn these, however, it is a good idea to be aware of them in order that we can identify a hard coral from another reef organism or substrate.

The different growth forms are as follows:

• Branching;• Plate;• Encrusting;• Massive or boulder;• Submassive or irregular;• Folios or lettuce-like;• Columnar or digitate;• Free living or mushroom.


To identify hard coral use the following decision rules:

1. If it is a protruding structure, waft the water near it with your hand.

Does it move?

YesIt is not hard coral and may be soft coral or sponge

No1. Look at the texture and try to

find the coral cups. Hard coral texture is like sandpaper or knobbly;

2. If the coral polyps are out, count the tentacles. Hard coral polyps have 6 or multiples of 6 tentacles whereas soft corals only have 8.


2. If it is an encrusting structure, look at the texture.

Does it have regular corallites and have a sandpapery or knobbly surface?

YesCheck it is hard to touch and it is probably a hard coral.

No1. Look at the texture, if it is smooth and a

purple, orange or red colour it is probably coralline algae;

2. If it has holes on its surface and feels soft to the touch it is probably either a sponge or an ascidian;

3. If it has regular corallites but is soft to the touch it is probably a soft coral.


3. If it is an encrusting structure, gently touch to check if it is hard or soft.

Does it feel hard and knobbly?


YesIt is probably a hard coral.

No1. If it is hard and smooth, it might be

coralline algae, which goes in the rock category for Reef Check;

2. If it is spongy, check if it is a soft coral, a sponge or an ascidian. If it has regular corallites but is soft to the touch it is probably a soft coral.

Photo by Jos Hill, 2002

Look at the texture. You can see the coral cups protruding

Branching



Each polyp lives inside this coral cup or corallite

Branching


These tube-like projections are the corallites in which the coral polyp lives.

Branching



Branching hard coral

Encrusting hard coral

Encrusting hard coral

Branching


Branching



Plate



HARD CORALThe reef builders

Encrusting

Note the ‘knobbly’ texture.

Encrusting hard coral ‘hugs’ the substrate to which it is attached and will tend to be a few mm thick.

Photo by Dean Miller, 2002

Note the ‘knobbly’ texture. If we could get a closer look you would see tiny holes that are the corallites.


Encrusting


Note the knobbly/sandpapery texture.


Encrusting



The corallites on this species are larger than previous examples. This makes this hard coral easier to identify.

Massive or boulder



Massive or boulder

This coral colony is several meters in length. Some massive corals can be hundreds of years old.



Submassive

Note the ‘knobbly’ surface.



Submassive

Look at this polyp. There are 24 tentacles (6 x 6) which means it is a hard coral. This particular coral feeds in the day time so is often mistaken for a soft coral. If you wafted these polyps quite hard they will retract and you’ll see the hard skeleton beneath.

Watch out for this one!



Foliose or lettuce

Note the sandpaper-like texture.



Digitate

Each of these projections is a corallite.



Mushroom or free-living

Mouth

Unlike other corals, mushroom corals do not attach itself to the reef rock. Additionally, they do not live in colonies, but alone as single polyps.



Mushroom or free-living Watch out for this one!

Some types of mushroom corals feed in the day time and can be mistaken for anemones. Although not all anemones have anemone fish in them, if you see one of these with no fish, give it a waft and you’ll see the hard skeleton underneath.



Blue coral

Blue coral is not a true hard coral as it has a blue argonite skeleton instead of calcium carbonate/limestone. However, as its skeleton is hard, it is a reef-builder and is, therefore, included in the HC category for Reef Check.

Blue coral looks like a submassive hard coral.



Fire coral Notice the tiny hairs.

Fire coral is not a true hard coral. In fact, it is a hydroid. However, it has a hard skeleton and appears the same as a hard coral people tend to have no problems with identifying this as a hard coral for Reef Check. The only thing to be aware of is that the tiny hairs sting!



Organ pipe coralNotice that this coral’s polyps have 8 tentacles. In the next section you will learn that soft corals have 8 tentacles, which can be a good way to tell them apart from hard corals.

Organ pipe coral is in fact a soft coral. However, it is unusual for soft corals in that it makes a hard, red skeleton and is, therefore, a reef-builder and included in the HC category for Reef Check.

If you see this coral, waft the polyps gently and see them retract into a red skeleton…but remember that red is filtered out of the water at shallow depths so this skeleton may look brownish underwater.



Organ pipe coral

This is the organ pipe coral skeleton. Notice the pipes!


Summary

• Calcium carbonate skeleton. Waft the water and it won’t move!

• Polyps have 6 or multiples of 6 tentacles, except fire coral, blue coral and organ pipe coral, which are also included in hard coral;

• Mostly night feeders. Exceptions have large polyps and you can count the tentacles and/or waft to see a skeleton underneath;

• Look for corallites that are fairly regularly spaced;

•Different shapes exist – don’t be caught out by encrusting hard corals as these are sometimes overlooked;

• Look at the texture, think sandpaper or knobbly surface!

• Mushroom corals are hard corals. Don’t be caught out by those that feed in the day and may look like anemones.

BLEACHED HARD CORAL Global warming indicator

Reef Check code: HCB

BLEACHED HARD CORALGlobal warming indicators


The white patch here is bleached and the brown parts are unbleached.

Bleaching is when the zooxanthellae (algae) living in the coral’s tissue is expelled. As this algae is also a pigment in the coral, when it is expelled many corals appear white because we can see their calcium carbonate skeleton through their thin tissue.

As the zooxanthellae provide corals with 90% or more of their total food intake, if they sustain their bleached state, they starve. Starvation does not necessarily mean death and many corals will recover their zooxanthellae when the stressor is removed. However, should the stressor remain for many days or weeks the coral’s immune and reproductive systems may first become impaired and they may die.



Global warming appears to increase the frequency and intensity of ENSOs. As a result it is feared that coral bleaching events will become more frequent and severe as a result.

Bleaching happens when the coral is under stress, such as, sea surface temperatures (SSTs), which are higher than corals can tolerate. High SSTs of 29ºC or higher frequently occur when we have an El Niño Southern Oscillation (ENSO) weather event.



Reef Check surveys document bleaching on coral reefs and this data will help scientists understand how reefs are affected by this phenomenon.





This coral is only partially bleached. This means that the zooxanthellae algae have only been expelled from the coral polyps that appear white.




SOFT CORAL Non-reef builders

Reef Check code: SC

Soft corals do not build reefs as their skeleton is made from soft tissue that is supported internally like re-enforced concrete by a matrix of calcareous elements.

Soft corals can be identified from hard corals by wafting the water column and the whole structure will move. Many soft corals will also have their polyps out during the daytime and you can count their 8, hairy tentacles. (remember hard corals have 6 or multiples of 6 tentacles). To identify encrusting soft corals, you can gently touch them and they will feel spongy.

The soft coral category also includes zoanthids. These are not true soft corals but fill the same function as non reef-building structures.

SOFT CORALNon-reef builders


To identify soft coral use the following decision rules:


Does it move?

YesIt is not hard coral and may be soft coral or sponge





2. If it is a soft, encrusting structure, look for regular corallites or feeding polyps (many soft coral polyps are out feeding during the day, whereas hard corals tend to feed at night).

Does it have regular corallites or protruding polyps?

YesIt is probably soft coral. If the polyps are out check there are only 8 tentacles.

NoIf it has holes larger than 1mm diameter on the surface then it is probably a sponge or an ascidian.



Notice the 8 tentacles. Soft coral tentacles also tend to be hairy or feathery.



Count the 8 tentacles



This soft coral will sway when wafted.

The ‘fluffy’ surface is the polyps. When these polyps are not feeding the surface of this coral appears leathery.



This is a close-up of the same type of soft coral seen in the previous picture. Here you can see the polyps more clearly.

This is what the polyps of this coral look like from up close. Note the 8 tentacles.



Some soft corals look like trees and many can be bright colours.



This ‘finger’ soft coral would move when wafted. If you look closely you would see tiny pin-prick holes that are the corallites.







The ‘fluffy’ appearance is the polyps.


Zoanthids

Zoanthids are not true soft corals, however, they can cover huge mats of reef and because they are non-reef builders like the soft corals, we count them under this category for Reef Check.


Zoanthids look like little cogs of about 1cm diameter, that have a mouth in their centre and are surrounded by little ‘teeth-like’ tentacles.

Zoanthids can live separately as in this picture or in colonies where they are connected to each other just like most corals.


This picture illustrates colonial zoanthids. They appear like they are made out of plasticine. If you waft your hand over them, they will close up as illustrated below.

These colonial zoanthid polyps are ‘open’.

These colonial zoanthid polyps are ‘closed’.


Zoanthids


Colonial zoanthids are frequently confused with massive and encrusting corals of the genus illustrated below. This is because the corallites of this coral resemble the soft zoanthid polyps.

To avoid confusion you can touch the surface and find the coral hard and the zoanthids soft. Or you can gently waft your hand over the top and see that the zoanthids will close up but the coral’s skeleton won’t budge.

These corallites are part of this coral’s skeleton. Go back to the last slide to make sure you can see the difference.


Zoanthids


These are solitary zoanthids. Although their tissue is separate they normally occur in groups. These zoanthids will also close if you waft your hand over them.


Zoanthids


Zoanthids tend to have brown, red or green centres as these below.


Zoanthids


Another example of colonial zoanthids where some are ‘open’ and some are ‘closed’.


Zoanthids

• Skeleton structure is soft;

• Polyps always have 8 tentacles, which are hairy;

• Polyps are often day feeders;

• Smooth texture with small, regular coral cup holes;

• Surface of some appears leathery or rubbery;

• Zoanthids most often occur in groups or joined in colonies. They can look like cogs surrounded like teeth and colonial ones look like they’re made from plasticine. To recognise, waft and they will close up.


Summary

BLEACHED SOFT CORAL Global warming indicators

Reef Check code: SCB

BLEACHED SOFT CORALGlobal warming indicators

Like hard coral, soft coral can also bleach. However, as soft corals do not contribute to the reef structure, we are not as concerned about this bleaching as we are about hard corals. Nevertheless, it is still interesting to note where bleaching occurs in order to get an idea of the affect of global warming on soft corals and their ability to recover.

We can measure recovery of reef organisms from detrimental impacts by monitoring the site year after year and comparing the survey results.

NUTRIENT INDICATOR ALGAE

Nutrient pollution indicator

Reef Check code: NIA

**Note that this category changed from Fleshy Seaweed (FS) in 2003

Firstly, note that algae can be green, red or brown!

NUTRIENT INDICATOR ALGAENutrient pollution indicators

Photo by Jos Hill, 2002Photo by Jos Hill, 2002Photo by Jos Hill, 2002



Note the fleshy body of this algae.

Coral reefs are naturally ‘oligotrophic’ or nutrient-poor environments and nutrients that become ‘available’ from dying animals and plants are quickly re-used and recycled into the living reef organisms. This leaves the surrounding waters nutrient-poor.

We all know that lots of nutrients, such as nitrates and phosphates help plants grow. Indeed, high nutrient conditions on a reef helps algae grow fast. Although algae on reefs is both natural and an important source of food for herbivores, in unnaturally high nutrient conditions, algae can out-compete coral, smother it and block the sunlight that is essential for 90% or more of its food. Therefore, proliferation of many types of algae is an indicator of nutrient pollution.


Nutrient pollution can occur when farming practices on land use fertilizers. These fertilizers run-off into the sea and increase the nutrient levels on the reefs.

It is important to not that although most kinds of algae can proliferate in high nutrient conditions, there are types of algae that are not indicators of nutrient pollution. These include Sargassum sp., Turbinaria sp., Halimeda sp., coralline algae and turf algae. Sargassum and turbinaria tend to proliferate then practically disappear seasonally. These algae can be recognised by having thick, leathery and spiky leaves. Sargassum also has little air bladders that hold it upright.

Halimeda looks like chains of flat, green discs. Coralline algae looks like a thin purple, orange or red covering on the reef surface and turf algae is like a short (few mm tall), wiry grass. If we see these algae on the reef, just look at what is below and note its presence in the comments section of the survey sheet.



IMPORTANT! This is halimeda and NOT a nutrient indicator algae!



This algae is like a turf algae, however, it has a jelly/fleshy coating that is more than just a few mm of wiry turf. This is, therefore, included in nutrient indicator algae.

If you are unsure whether it is turf algae (and therefore just noted in the comments section) or nutrient indicator algae, look for a fleshy ‘halo’.


This algae is fleshy, therefore counted as nutrient indicator algae.



Red and fleshy algae. If this is allowed to proliferate as it might in high nutrient conditions, it can smother the coral and prevent light to penetrate. Lack of light prevents the zooxanthellae algae inside the coral from photosynthesising.




See how this fleshy algae is competing with the branching coral for space and light.


This algae is beginning to smother the branching hard coral.



This algae, which looks like pencil shavings, can proliferate in high nutrient conditions.



This red algae grows like little red leaves.



As this fleshy brown algae grows over the dead coral, it can smother the surface and prevent baby corals from establishing themselves by blocking out the sunlight.


Summary


• The aim is to record blooms of fleshy algae that may be responding to a high level of nutrient input;

• . Examples of these types of algae are Ulva, various blue green algae, and bubble algae as illustrated here;

• Algae that are a normal part of a healthy reef, such as Sargassum sp., should NOT be recorded as NIA. Instead, record the substrate directly beneath the algae and note this in the comments section;

• Turf and coralline algae go under rock and halimeda goes under ‘other’.

SPONGE Sewage pollution indicator

Reef Check code: SP

SPONGESewage pollution indicator

Sponges are very simple animals and are filter feeders that clean the water of bacteria and other suspended organic particles. They work like suction pumps and can filter large quantities of water in a day.

As they are simple animals, they have no nervous network and so will not react if you waft your hand over their holes!

Neither do they have a system for cleaning their outer surface from particles from the water column that get sucked there as the sponge filters the water. Instead, little sea cucumbers do this job for them and you may see some sponges covered by little white worm-like sea cucumbers. Other sponges may be covered with a thin layer of silt.

Sponge texture tends to be matt rather than shiny.

Photo from Undersea Explorer, 2002


You’d expect to see more sponges in areas of strong currents where more food will be brought their way in the water column.

Sponges are very common components of coral reefs, although they tend not to make up a large percentage of the reef surface in the Indo-Pacific. Extensive coverage of sponge may indicate sewage pollution, as they are able to proliferate where there is more food. Extensive sponge growth takes up space from hard corals.


Sponges come in ALL shapes, sizes and colours!

They can be confused with ascidians (see the ‘other’ category).

Their tissue is fairly stiff and their skeleton is similar to that of soft corals, a matrix of hard elements called spicules. Patterns of these spicules can often be seen from the surface like splinters in the tissue or irregular lumps over the surface.

The network of small canals lead to a larger canal that leads to the ostia opening. Water is sucked into the

ostia by a suction current that is created by the collar cells that line the internal canals.

Water pumped out through the larger holes, this is called an osculum.

The sponge surface is a matt texture. And may be covered with silt and other organic debris that is too large to fit into the ostia.

Small, irregularly spaced holes called ostia cover the sponge surface. They lead to a network of canals, which are lined with collar cells. These cells create the suction current and sieve out organic debris (food) from the water.

Cross section through a sponge



To identify sponge use the following decision rules:


Does it move?

YesIt is not hard coral and may be soft coral or sponge.




2. If it is a soft, encrusting structure, look for irregular holes. THINK IRREGULAR is probably the best advise you can use to recognise sponges!

Does it have irregular holes?

YesIt is probably sponge or an ascidian. To tell these apart, waft the holes. If there is NO reaction it is probably a sponge. If the holes close up – it is an ascidian!

NoIf it has regular holes less than 1mm diameter then it is probably a soft coral.




Look at the matt surface, which is covered in little spikes from the spicules in its skeleton.

Notice how it cannot clean this debris out.



Note the holes (osculum). These are distributed in an irregular fashion over the sponge body.

Note the irregular, matt surface and irregular shape



Note these holes. They are fairly regularly spaced over this sponge.

Note the spiky surface.



Note the irregular, spiky surface.

Note irregularly spaced holes.



Note irregular, spiky surface.



Note irregular and spiky surface with irregularly spaced holes.

In a silty environment, sponges may frequently be covered in a layer of silt.



Spiky, irregular, holey surface.

Irregular and matt surface with one large hole.

This is an ascidian NOT a sponge. See ‘Other’


Summary

• Huge range of colours;

• Surface often matt or dull;

• Simple organisms with no set shape. Think IRREGULAR!

• Can assume a variety of shapes and sizes from small encrusting animals to large tube, barrel or foliose forms;

• To tell these from hard corals, waft and they will sway. To tell them from soft corals, look closely at the surface for irregular texture, covered in different sized holes. These holes will NOT close up if you waft your hand over them.

• To tell an encrusting sponge or soft coral from hard coral, look how ‘thick’ the structure is on the reef. Sponges and soft corals will be thicker.

OTHER Not indicators of impacts

Reef Check code: OT

OTHERNot indicators of impacts

This category contains both living and non-living elements of a coral reef that do not serve as indicators of human impacts for the Reef Check survey.

Some of the members of the ‘other’ category can be confused with members of the soft coral and sponge categories. It is, therefore, important to familiarise yourselves with these in order to avoid making these misidentifications.


This category can include the following – although this is not an exhaustive list!

• Ascidians;

• Hydroids;

• Anemones;

• Coralliomorphs;

• Gorgonians;

• Clams (but the shell comes under Rock).



Ascidians

These holes will close up if you waft your hand over them.

Ascidians (or tunicates or sea squirts) can easily be confused with encrusting sponges because or their irregular growth. They are also filter feeders and so are covered in inhalant and exhalent holes.

However, they are much more complex organisms than sponges and the holes will CLOSE if you waft your hand over them. Sponges will not do this!



Ascidians

Solitary as well as colonial ascidians exist. Solitary ascidians are often easier to recognise as they look like little bells. These solitary ascidians can occur in groups but their tissue is not joined (like the zoanthids).



Ascidians

Inhalant and exhalant holes. Waft and these will close.



Ascidians

These ascidians look like little bells. Waft over the holes and they will close!



Ascidians Ascidians tend to have a more shiny surface than a sponge. The holes will close when wafted.These little yellow

organisms are also ascidians. Waft and the holes will close.



Ascidians

This is quite common on the Great Barrier Reef. Most people just have to learn this one – but it helps to describe it like snot!



Hydroids

Hydroids are related to coral. They look like feathers or ferns and are often called stinging hydroids because they STING! Don’t touch!



Hydroids



Anemones

Anemones are also related to coral. They frequently have anemone fish living in them – however, not always. Be careful not to confuse these with the mushroom corals!



Anemones



Gorgonians

Gorgonians are actually soft corals but come under the ‘Other’ category for Reef Check. They are common in areas of high current where they position themselves against the current and filter out food from the water that travels across them.



Non-nutrient indicator seaweed

Halimeda is a green algae that excretes a calcium carbonate ‘skeleton’, which makes it difficult to digest by many herbivores and so serves as protection from many algae-eating organisms. Halimeda is common on some reefs and is not counted as a nutrient indicator seaweed. Therefore, put it in ‘Other’.



CoralliomorphsCoralliomorphs look like anemones. As both these belong in ‘Other’ there is no need to differentiate between the two.

ROCK Hard substratum

Reef Check code: RC

ROCKHard substratum

Rock can be defined as any hard substratum that is either bare rock or covered in turf algae or encrusting coralline algae, barnacles, oysters etc. Rock also includes dead coral that is more than 1 year old, i.e. is worn down so that few corallite structures are visible, and covered with a thick layer of encrusting organisms and/or algae.

• Turf algae is like wiry turf no more than a few millimeters long;

• Coralline algae is encrusting and looks like lichen that is pink, purple, orange or red;

Rock is important because it is a hard substratum on which new coral or other organisms can settle.


This is coralline algae, therefore, rock for Reef Check.

The whole of this picture would be classified as rock

ROCKHard substratum


ROCKHard substratum

This has a think layer of silt


ROCKHard substratum

This pink is coralline algae (rock for Reef Check)

The whole of this picture would be classified as rock


ROCKHard substratum

This is actually hard coral. The little bumps are the corallites. The ‘hole-like’ ones are irregularities. If you gave this a gentle touch, you would see that it was hard coral rather than a sponge or ascidian.

Rock


ROCKHard substratum

This is broken dead coral (rubble). It is classed as rock because it has encrusting organisms growing on it so that it is now consolidated rather than lose. Had it been lose rubble that could be moved around it would go in the rubble category.

This is sponge. Look at the spiky texture.


ROCKHard substratum

The shell of this clam would come under rock.


ROCKHard substratum

The corallites of this dead coral are very eroded. This is therefore rock.

These are ascidians.


ROCKHard substratum

The corallites of this dead coral are very eroded. This would come under rock.


ROCKHard substratum

Again, the corallites of this dead coral are very eroded. This is, therefore, rock.

Summary

ROCKHard substratum

This includes:

• Bare rock;

• Turf and coralline algae;

• Barnacles or oysters etc;

• Coral that has been dead for over a year;

• Rubble that has been ‘cemented’ together by coralline algae.

Recently Killed Coral Indicator of recent disturbance

Reef Check code: RKC

RECENTLY KILLED CORALIndicator of recent disturbance

The aim here is to record recent mortalities in hard corals. It is important to be able to identify recently killed coral from coral skeletons of coral that has been dead for a while. The following guidelines may help with the identification of this category:

• Killed during the last year. This means that corallites will not be very eroded. If the corallites have been eroded down and are covered in encrusting organisms and/or are a dull grey colour, then it is classified as rock;

• The skeleton may still be white if very recently killed because it is made out of limestone. It may be slightly overgrown by algae as this may not take long to settle. Look under the algae for corallites that are not eroded and/or whitish skeleton;

• If it is slightly grown over with algae – note it as NIA/RKC or OT/RKC depending on whether it is nutrient indicator algae or other algae.



If you look closely, the corallites are only slightly eroded here. This would be on the borderline of RKC and nearly rock.

This is very eroded and covered in coralline algae. This would come under rock.

This part has died very recently as it only has a very thin layer of algae covering it. This algae is not thick enough to count as algae so just put RKC.

This looks white like it has very recently died.

This part is still alive hard coral.



This ‘halo’ of jelly-like algae is cyano-bacteria which is a nutrient indicator algae. Put NIA/RKC on the survey form here.

Note the skeleton is still white, so this is very recently killed.



This photo was taken in March 2002 when there was severe bleaching on the Great Barrier Reef. This white part is either bleached and still alive or recently killed. It is hard to tell – however, seeing that the rest of this branching hard coral colony is recently killed, you can assume that this part is also.

This part is recently killed but now covered in a thin layer of algae. Here you can put NIA/RKC.



Live hard coral

This photo was taken a couple of weeks after bleaching hit this area. Apparently all this NIA only took a couple of weeks to cover this coral! In other areas it can take a lot longer. A close look at this coral will show that the corallites were not eroded and white underneath. Therefore, put NIA/RKC.



This is recently killed. Note the white skeleton.

This nutrient indicator algae has not taken long to partially cover the recently killed coral. Put NIA/RKC for the areas covered with this algae.



This algae is too thin to worry about. Put RKC.

This algae is starting to get ‘fleshy’. Put NIA/RKC here.

Summary


This includes coral that has died in the last year (recently). This can be a difficult category to define – therefore note the following:

• Corallites are not eroded much;

• Some white skeleton showing;

• Only partially grown over with encrusting algae – where corallites and/or white skeleton is still visible;

• If it is slightly grown over with algae – note it as NIA/RKC or OT/RKC depending on whether it is nutrient indicator algae or other algae.

RUBBLE Unconsolidated material

Reef Check code: RB


RUBBLEUnconsolidated material

Rubble is classed as rocks between 0.5 and 15 cm diameter. If it is larger than 15 cm it is rock, smaller than 0.5 cm and it is sand.

As rubble is unattached to the reef, wave action will make it tumble around, which may knock off any new corals that have settled.

When rubble has been ‘cemented’ together by coralline algae, we call it rock as it is no longer unstable.

SILT Indicator of soil erosion or dredging

Reef Check code: SI


SILTIndicator of soil erosion or dredging

Tap this and it will rise from the reef in a little cloud.

Silt is sediment that remains in suspension if disturbed. Note that these are practical definitions not geo-technical. Often, silt is present on top of other indicators such as rock. In these instances, silt is recorded if the silt layer is thicker than 1 mm or covers the underlying substratum such that you cannot observe the color. If the color of the underlying substrate can be discerned, then the contact will be the underlying substrate NOT silt.



One way to double check that it is silt is to tap it and it will come up from the substrata like a cloud.



Remember if you can’t see the substrate colour underneath, it is silt.

Nutrient indicator algae.

SAND Non-reef area

Reef Check code: SD

SANDNon-reef area

Sand is a natural component of coral reefs. This category helps us to see when the transect hits a sandy patch in-between the reef area.

If you are unsure as to whether it is sand or silt, pick a bit up and drop it. If if falls straight to the ground, it is sand. If it forms a cloud in the water column, it is silt.

www.ReefCheck.org

Phew! Well done!

This presentation was produced by Jos Hill, 2003©. Any questions, please contact Jos at [email protected]

Ph: +61 (0) 7 4721 5001Mob: +61 (0) 415 446 646

mailto:[email protected]

Documents

Substrate ID Training Global Community Coral Reef Monitoring Program