Research Is A Dangerous Business

When people talk about risk at work, they normally mean the risk of getting laid off, terminated, losing a business deal, and probably encountering some minor accidents like electrocution while charging their electronics. 

Unlike these risks, the risks you encounter during research are far more unpredictable because you work with unpredictable subjects; the weather (climate scientists), wild animals (zoologists), chemicals (chemists), toxic jellies (marine biologists), unpredictable monkeys (lab scientists) and sometimes, the product of your own research - worm holes and such (physicists). Even in social sciences, the research is often far more dangerous than your average nine-to-five job.

Research isn't your typical 9-5 job.

Image: www.the-scientist.com

One particular technique in psychology, called participant observation, involves taking part in the activities of those you want to study. For example, if you wish to study the drug cartel, you would need to actually get your hands dirty. Sociologist Mick Bloor, a professor at the Cardiff School of Social Sciences once ended up in a bar fight while studying male prostitution in Glasgow. Lorraine Dowler from the Pennsylvania State University was forced to flee when her interviewee became the target of a street-level assassination attempt. Social scientist Frank Burton woke up one morning to find a submachine gun pointed at him. The body of Ken Pryce was found washed up on a Caribbean beach after investigating criminology in Jamaica.

These are just of the few workplace hazards that face researchers at work. We have yet to include stories of marine biologists who have face sharks and other dangerous marine predators, zoologists battling malaria, herpetologists getting bitten by snakes, and conservationists and medical scientists battling fanatic animal-rights activists. All very real possibilities in the modern world.

In April 2013, an animal-rights group that calls itself Fermare Green Hill (or Stop Green Hill) occupied an animal facility at the University of Milan, Italy, at the weekend, releasing mice and rabbits and mixing up cage labels to confuse experimental protocols. Certainly makes a strong case for microchip IDS and tattoos. Researchers at the university said that it will take years to recover their work. Michela Matteoli, a neurobiologist who works on autism and other disorders and lost most of her own research in the attack, says that she found some research students crying in the disrupted facility on Monday morning. Many of the animals at the facility were genetic models for psychiatric disorders such as autism and schizophrenia.

A study conducted in 1994 by Brian D Crandall and Peter W Stahl intended to investigate whether humans could digest bones. They trapped some shrews and after skinning and brief evisceration, they boiled one of the carcasses for approximately 2 minutes before swallowing it whole; head, limbs, body and tail. Without chewing. Talk about taking one for the team.

So it's very disrespectful for anyone to brush aside any researcher's project and label them as useless.

Research is not just for geeks. It's also for James Bond. 

Research Is A Dangerous Business for Some

When people talk about risk at work, they normally mean the risk of getting fired, getting hit by a bus, and probably encountering some minor accidents like electrocution while charging their electronics. 

Unlike these risks, the risks you encounter during research are far more unpredictable because you work with unpredictable subjects; the weather (climate scientists), wild animals (zoologists), chemicals (chemists), and sometimes, the product of your own research (physicists). Even in social sciences, the research is often far more dangerous than your average nine-to-five job.

One particular technique in behavioral psychology, called participant observation, involves taking part in the activities of those you want to study. For example, if you wish to study the drug cartel, you would need to actually get your hands dirty. Sociologist Mick Bloor, a professor at the Cardiff School of Social Sciences once ended up in a bar fight while studying male prostitution in Glasgow. Lorraine Dowler from the Pennsylvania State University was forced to flee when her interviewee became the target of a street-level assassination attempt. Social scientist Frank Burton woke up one morning to find a submachine gun pointed at him. The body of Ken Pryce was found washed up on a Caribbean beach after investigating criminology in Jamaica.

These are just of the few workplace hazards that face researchers at work. We have yet to include stories of marine biologists who have face sharks and other dangerous marine predators, zoologists battling malaria, herpetologists getting bitten by snakes, and conservationists and medical scientists battling fanatic animal-rights activists.

Image: www.the-scientist.com

In April 2013, an animal-rights group that calls itself Fermare Green Hill (or Stop Green Hill) occupied an animal facility at the University of Milan, Italy, at the weekend, releasing mice and rabbits and mixing up cage labels to confuse experimental protocols. Researchers at the university said that it will take years to recover their work. Michela Matteoli, a neurobiologist who works on autism and other disorders and lost most of her own research in the attack, says that she found some research students crying in the disrupted facility on Monday morning. Many of the animals at the facility were genetic models for psychiatric disorders such as autism and schizophrenia.

A study conducted in 1994 by Brian D Crandall and Peter W Stahl intended to investigate whether humans could digest bones. They trapped some shrews and after skinning and brief evisceration, they boiled one of the carcasses for approximately 2 minutes before swallowing it whole; head, limbs, body and tail. Without chewing.

So it's very disrespectful for anyone to brush aside any researcher's project and label them as useless.

Research is not just for geeks. It's also for James Bond. 

Which Is More Important: Human Welfare VS Animal Welfare?

When a tiger starts killing people, regardless of how endangered it may be, it has to be put down - at the minimum relocated to life in a zoo where it cannot harm humans. Similarly, if the extinction of a particular species could ensure the survival of mankind, hand me the shotgun please. That said, I cannot think of a single case of any organisms meeting this criteria except for some bacteria.

Of course, things have yet to go that far. We're not facing some kind of apocalypse, and certainly not extermination by aliens so we can still work on sustainable development to achieve a win-win situation. But some people, and I seriously mean somepeople, emphasize the well-being of animals more than the well-bring of their own kind. And I'm not talking about the Japanese-hunting-whales-thingy. I'm against that, too.

Please stop whaling. Image: sustainablesushi.net

Some animal rights activists had recently pressured airlines and ferry companies against transporting animals to the UK for research purposes.

Lord Drayson, who was a minister in the last Labour government, said "extremists" had picked off the companies, which had pulled out of transporting laboratory mice and other animals. The Times reported that Stena Line had followed DFDS Seaways in halting the carriage of test animals, closing the last sea route for medical researchers. The Channel tunnel had long refused the trade, it said, while no UK-based airline, including British Airways, would carry laboratory animals.-- http://www.guardian.co.uk

Image: sciencedaily.com

It's understandable that these animal lovers treasure animal lives. But hey, medical research is important because we have yet to find a cure for AIDS, cancer, Alzheimer's, and there are new diseases emerging every few years. Halting medical research could spell disaster because any new disease nowdays could potentially push the entire humanity towards extinction. Just think of it as a safety net to ensure the continuity of our species.

In the UNited States, and most other research heavy nations, there are extensive regulations in place to ensure research animals are humanely cared for.  The US alone has the governmental agency, the USDA, and groups like AALAS and AAALACi training and monitoring facilities that conduct research.




Sure, people get concerned about research on stolen pets, cute monkeys, cuddly bunnies and the like.  Fact is 98% of all research animals are rats and mice purpose bred for this purpose.  Keep in mind many of the people saying this should stop have multiple mouse traps in their own garage.  We are talking animals housed in very clean conditions, given full time care, veterinary support, food, water and n exchange allow scientists to research disease.  That is a far cry from Decon poisons in the garage for the wild population.

Laboratory mice reach sexual maturity by six weeks of age, and could produce up to 14 pups after a gestation period of 19~21 days. Mice infestation is a problem in many parts of the world so why worry about them? They are the most adaptable animal after humans, and most importantly they are the least of our concern when it comes to animal conservation.

Image: sciencedirect.com

The vast majority of research animals are the rodent family.  Dogs must come from documented breeders - most of whom are dedicated to the lab animal industry and are also inspected and heavily regulated.  No shelter pets here.  Many species of Non Human Primates are no longer used. 

In addition, many advanced in pet medicine have come out of this.  That vaccine you give Fido, or that pill you give your cat was made possible through other research animals and scientists.

Some research which focus on saving a particular species would inevitably require some individuals from the species itself to be tested, which is in itself a justifiable thing. But if people die from a disease whose cure is already at the brink of discovery, but made impossible just because some preposterous animal activists who couldn't understand the importance of medical research and value the life of a pest more than that of a fellow human being decided to brand shipping companies as cold blooded accomplice, then humanity is doomed.


To come think of it, thousands of cancer patients, Alzheimer's patients are waiting for medical breakthroughs all over the world, and yet the animal rights activists couldn't understand the need to sacrifice a few rodents?

They should be charged with manslaughter. OK, that was in jest, but this is not undertaken lightly.  The people involved in this research are generally good and compassionate people.  Yes, there are a few whackos like any segment of humans, and unfortunately they get much bad publicity.  But 99.99% are loving and caring and intelligent people that deliver the best care they can to their charges.

Did you also know that there is a huge component of research that involves enrichment for animals?  We are talking toys, cool housing, nesting materials and treats.  I am not saying living as a research animal is a joy, it does ultimately end in a hopefully humane death.  But I can safely say 99% of research animals live more comfortably than 50% of household pets. There is no massive outreach to ban and stop people who lock their dogs in a room all day or a crate for 8 hours a day while at work.  Yet in the research side this is illegal unless they are exercised.

People have to stop being so squeamish about topics like food, research and biology.  Yes, its a complicated topic, but not that hard to understand and appreciate.


And to stave off those that might say I am a sadistic beater of animals I myself am a proud pet owner and go to great lengths for their care and comfort and that I'm against poaching, consumption of shark fin, and unplanned deforestation. 

info: http://www.guardian.co.uk/science/2012/mar/14/animal-rights-activists-research-transport?CMP=twt_fd

Limulus - the Horseshoe crab

The Horseshoe Crab

Jonathan Lowrie

Calling a horseshoe crab a crab is a misnomer, since this distinctive arthropod is more closely related to spiders and other arachnids than to crustaceans. The horseshoe crab is truly a living fossil.  Its only living relatives are found in the East Indies, China and Japan.  But its earliest relatives lived in the Devonian seas more than 350 million years ago.  The genus Limulus, to which the modern horseshoe crab belongs dates back to the Triassic period, the same time as the first dinosaurs. .  Because they are so unique, they are cannot be confused with that of any other creature.

The classification of the Horseshoe crab is as follows: Phylum Arthropoda, Class Merostomata,  Family Limulidae, Genus Limulus, Species polyphemus . An adult female Limulus will attain lengths of 24 inches.  Most first time encounters can be rather scary, because they also have a very long spiked tail. Contrary to public opinion, the tail is quite harmless and the horseshoe crab should never be picked up this way. This unique creature lives on sandy or muddy bottoms.  Because of its propensity to burrow, it prefers a softer sediment.  It frequents intertidal and sub-tidal regions, rarely going deeper than 75 feet.  The Atlantic Horseshoe crab may be found from the Gulf of Maine all the way to the Gulf of Mexico. They start of life very light in color.  When small, they are a sand color and, as they molt and grow older, they darken.  After the terminal molt, they are a deep brown color.

The horseshoe crab has six pairs of appendages.  The first pair is called the chelicerae, followed by 5 pairs of legs, the first of those being called pedipalpi.  The pedipalpi also act as modified claspers in male horseshoe crabs.  The last pair has a special adaptation to facilitate digging into the substrate.  The mouth has no appendages of its own, quite different from true crabs. The chewing mill is the opening of the mouth, and is located at the base of the legs. The only other appendages are the 5 pairs of book gills, so named because they are large, and sheet like and resemble the pages of a book.  The eyes of Limulus are two lateral bump like protrusions and are not stalked.  There is also a third median eye, which is located beneath the foremost spine on the horseshoe-shaped prosoma.

The typical diet of Limulus is clams, worms, and other invertebrates which it grinds with the burr-like bases of the walking legs, which surround the mouth. They collect their food via foraging.  These animals are an incredible sanitizer of the sea, as they will forage in the muck and consume both healthy animals and sick and injured animals. 

Limulus are also known for their seasonal migrations and breeding.  During the first full moon and high tide of spring, thousands of horseshoe crabs return to shore to mate.  The females dig small burrows in the sand to deposit the eggs, after which the male will release sperm to fertilize them.  The timing is such that the females dig and deposit eggs, and the males, further out in the water, release sperm as the waves come in to wash it over the deposits. One can find the many eggs masses along the beach in late spring.  The masses are found as clumps of greenish eggs, about 3 mm in diameter.  It takes only a few weeks for them to mature and be washed back out to sea, where the juveniles spend time as a miniature adults living a benthic lifestyle.

Horseshoe crabs travel mostly on the surface of the seafloor, but they can also swim to escape predation or to move around an obstacle.  They do this by swimming upside down; using the large carapace as a wing, they point their long tails in the direction they wish to go, and beat their kegs frantically.  Although not the most efficient means of propulsion, they can get off the surface enough to catch some waves and travel quite a distance down the beach.  Since they live in the tremulous region of the intertidal zone, they must have a means to right themselves when flipped by a wave.  Fortunately, Limulus has such a means - its tail.  The tail is a long dagger-like projection that may be 12 inches long.  It is covered with many smaller protrusions and spikes.  They will use this tail as a cantilever to right themselves when turned over.  Because of its sinister appearance, the tail sometimes has the reputation of being venomous or capable of stinging.  Neither is true - the worst injury once could sustain from a Horseshoe crab is stepping on the tail, an action which would probably not even break the skin.

Limulus has an interesting history as well.  It was once used en masse as a fertilizer.  Tens of thousands were harvested and spread on fields to fertilize for the summer harvests.  It was a cheap source of fertilizer, since the flesh of the Limulus is inedible to humans and they are considered a nuisance species.  Most clam and oyster farmers dislike the presence of Limulus because they can disrupt their beds and, in the summertime, the beaches are clogged with thousands of crabs.  Trawlers also dislike the tons of crabs that take up valuable net space each year.  So, these animals were collected with little regard.  It was not until the 1970’s that scientists found a special use for Limulus.  Their blood.  Because of the unique properties of their blood, they make an excellent biomedical specimen.  In fact, they have a unique immune system. Because of this, their blood reacts very strongly to certain pathogens.  So, each year, small amounts of blood are collected harmlessly from these animals and used to test the purity of many vaccines, antibiotics and other injectible medications.  It is now illegal to purposely kill Limulus in most coastal states.

Limulus can sometimes be found for sale at  local fish stores.  Once one takes into account the reasons they are being sold and then looks at their natural lifestyle, it is apparent that this species is just not suitable for the home aquarium.  Often they are sold as ‘sand sifters’, and they do just that.  As mentioned, Limulus is an excellent burrower and will adeptly crawl though the substrate.  Herein lies the problem - they do this almost constantly.  Unless provided with a huge tank, they will soon be under the live rock formations, and they will easily topple over corals, and rock.  There are also dietary problems.  We keep live sand, trying to keep the bacteria, and infauna heavily populated.  By confining a creature that constantly sifts through sand for food, eating molluscs, worms, and such, it can easily wipe out a live sand bed of its beneficial populations.  In nature, they feed over many square feet, rarely returning to an area for many days.  But, in a 75 gallon tank, the small area will force Limulus to completely clean the sand bed of food.  Sadly, many times Limulus will slowly starve to death because it cannot forage enough food from an aquarium.  And since they are always offered as beige young animals, few people will ever realize they will reach 24 inches in length.

If one is already purchased, or if the resources for the proper habitat can be provided, the next obstacle is temperature.  Any organism that is found from the Gulf of Maine to the Gulf of Mexico can tolerate a wide range of temperatures.  Interestingly, the horseshoe crab cannot easily adjust to these large changes.  There are many separate and distinct populations of Limulus along the Eastern coast, so its critical to know the origin of the horseshoe crab and to what temeperature range it is best suited.  In the Gulf of Mexico, they can easily withstand 76 to 80 degrees.  Yet, the Limulus off the Carolina coast have a tolerance for the mid 70’s only, while those from further north require 60 degrees or cooler waters to survive. Because of their habits, movement, and propensity for growth, Limulus is simply not a species that should be kept in an aquarium. 

It is always fascinating to observe a true living fossil, but these creatures are best left in nature.  If one is fortunate enough to see one at the beach, please keep a few things in mind.  They are 100% harmless.  Never pick them up by the tail, but grasp firmly onto the carapace and hold them.  They will thrash about , ‘close up,” and try for form a ball, but eventually they will relax,  and one can then observe the book gills, chelicerae - and even tell if it’s a boy or girl.  In males, the first pair of appendages, the chelicarae, have a thickened claw, much like boxing gloves.  The females do not have this.  And if, by chance, on a spring time full moon night at an East coast beach, you happen to be walking along the sand, keep your eyes open for one of the most spectacular events you will ever see.

Live Sand: In depth discussion

Live Sand

by

Jonathan Lowrie

Some definitions to begin with:

Infauna	Animals that live within sediments on seafloor bottom.
Epifauna	Benthic animals that crawl along the bottom or are firmly attached to bottom structures.
Macrofauna	Macroscopic animals that live on or in sediment.
Microfauna	Those animals less than 50 microns that live within the sediments.
Meiofauna	The animals between sizes.  Also between spaces- these animals live within the interstitial spaces of the sediments.
Closed System	System which has no connection with outside environment.  A typical home aquaria.
Open System	A system with a direct interchange with the outside environment.
NNR	Natural Nitrate Reduction. A concept of 'natural' filtration using a plenum and live san layers.
Plenum	A space or cavity. In the case of san beds, a raised space off the bottom of the aquarium with a barrier covered with a thickness of sand.
'Natural'	A process that occurs in captivity in much the same fashion as in nature.
Ecosystem	All the organisms in a biotic community and the abiotic environmental factors they interact with.
Live Sand	Simply put: sand with living organisms contained within the interstitial spaces, or on the sand grains.

Sand at Wikipedia

SeaFloor Characteristics

• Seafloor characteristics are a crucial part of the habitat of benthic organisms.  As the substrate supports the weight of many animals considerably more dense than seawater.

•  The seafloor also acts as a mechanical barrier to collect and accumulate plankton, waste material, and detritus.  A variety of worms, echinoderms, mollusks, and crustaceans obtain their nourishment from this organic matter.

• Benthic organisms are adapted for a particular bottom type; and character of life there, to a large extent, is dependent on the properties of bottom substrate.

• This bottom material varies from very solid rock to very soft, loose deposits.

• The actual composition of the seafloor is determined principally by the amount of energy available.  In nature this is through wind driven waves primarily.

 • In an aquarium, it can be from the use of auxiliary pumps.

• Benthic animals play an important role in mixing and sorting of sediments by their burrowing and sorting of the sediments by their burrowing and feeding activities.

•  Oxygen and water from the sediment surface are transported down into the sediment through these tubes and burrows.

• Further modification of sedimentary characteristics is accomplished via cementing particles together to form tubes, and by compacting sediments together as fecal pellets and castings.

• The distributional patterns of benthic animals and plants are strongly influenced by the form and texture of their substrate. 

• These factors determine effectiveness of locomotion, or for non-motile species, the persistence of attachment to bottom.

Animal Substrate Interaction

Because of the different distributions, unique adaptations have developed allowing for specialization to those environments. 

• The particle size and organic content of the bottom material limits the versatility; and thus the distribution of specialized feeding habits.

Before you say ‘huh?', allow me to explain in terms of our captive closed systems.  All the diverse habitat types in nature all support a selective array of animal life. 

• What exists in one biotope, most probably will not exist in another.  In our aquariums, this translates well into the discussion of live rock and live sand. 

• Live rock is a solid substrate.  It has a variety of live within and about it.  From small sponges, tunicates, to corals. 

• Within may be algaes, bacteria, and more.  All of these animals and plants have adapted to life on a hard substrate such as the live rock.  Sand on the other hand is a totally different environment

• It is much softer, and will not offer the same advantages to most of the animals.  Yes, some will be able to make the transition, and tolerate the new habitat, but many will not migrate to the new habitat.  Hence the reason why adding live rock to ‘dead’ sand will not ultimately lead to a ‘live’sand bed.

 Before the critics jump up and yell, let me explain my opinion of ‘live’.  Yes, the sand will have life in it.

But will it have the typical life found within that format of sediment?  No.

 It has to come from somewhere, and sand animals and plants as a rule don’t live on rock, and vice versa.

• Suspension feeders depend on small plankton or detritus for nutrition.  Filtering devices or sticky mucous nets are employed to collect minute suspended food from the water. Suspension feeders generally require clean water to prevent accumulation of indigestible particles.

• Deposit feeders engulf masses of sediments and process them through their digestive tract.  They extract nourishment through their digestive tract from the organic matter of the sediment in much the same manner as an earthworm.

If we are to keep obligate suspension feeders, or deposit feeders in our aquariums, we must be sure to provide them the proper and suitable habitat to thrive in.

Sediment Types and Sorting

Many reef sediments are terrigenous in origin (in Atlantic reefs).  Terrigenous sediments are those originating from terrestrial origins, and entering the ocean through streams and rivers.

 The Atlantic Ocean has more large volume rivers that dump literally millions of cubic feet per hour of terrigenous sediments into the oceans.  Much of this falls along the Continental shelf, but some does reach the reef zones.

 In the Pacific Ocean, there are fewer rivers with huge outflows, as well as deep trenches to collect and accumulate this sediment.

Another sediment type of reefs is biogenic sediment.  Biogenic sediment is derived from living animal and plants.  These are sediments formed from diatoms skeletons, and skeletons of other animals and plants that have passed through the water column.

Biogenic sediments usually contain a high level of Calcium Carbonate.

Now, again, how does all this relate to the home aquarium?  Coarse sediments are very difficult for animals to inhabit. 

• The sand grains are cutting, and have a considerable mass that can easily crush the soft bodied animals.  Most life here tends to be tube burrowing worms, and mollusks.

 • Many are considered meiofauna as they exist in between sediment partakes as to prevent this destruction from abrasion.

• Finer sediments from sandy silt to mud typically have a rich fauna.  Thousands of species can be found in healthy sheltered mud flats and grass beds.

• These natural sediment beds have another role as well.  That role is as a mineral source.  In nature, marine sediments will sometimes release minerals that will precipitate to form irregular deposits on the seafloor.

• Coral skeletons, and Halimeda is composed of calcium carbonate is composed of calcium carbonate in the form of aragonite.  While many of the red algaes, and forams have CaCO3 in the form of calcite. 

• Calcium carbonate can exist in three forms- two of which are important to reef systems.  Those are calcite and aragonite.

In the Aquarium

So now I am back to the nature of the sand bed of the home aquarium.  Typically, folks dump in a uniform size gravel of aragonite based sand.

Problems:

 • Inadequate habitat

 Using a fine sand and a medium sand and a coarse sand you can replicate the diversity of sediments to a limited extent.

Layers:

• Good, Bad, or indifferent

Depth:

• Deep?

• Shallow?

• Slopped?

A Mixed Sediment Filtration System:

  Another more complex method is to have a mixed sediment system.  This is involves using a sump and or refugium as well.  Rather than go into great detail and stir up controversies, I will say this:  Refugia with seagrasses and mangroves serve many useful purposes.

 As a habitat for small shrimp, fish, mollusks, etc.  And as a means to filter the aquarium.  When I say filter- I also include mechanical and biological filtration.

 Seagrasses in nature act as a baffle for sediment suspended in water, and will draw these sediments down to their bases.  In a properly flowing system the seagrasses can serve much the same purpose at home.

NNR

Wait!  Someone is bound to ask why?  Why do we want to increase diversity if our current NNR or other systems seem to work?

A few comments:

• Live sand will not form from dead sand.

 Period.

 Louis Pasteur proved the world wrong on spontaneous generation, and it won't happen in your reef tank.  No matter how good the live rock is, it won't provide what is necessary for a healthy sand bed.

Does NNR work?

• In many cases yes.

Is it the best system for me?

• Most often, no.

         • Degrades over time

         • Does not allow for diversification

         • Artificial means to accomplish a natural function

 On shipping live sand. 

Sand is rough  Its cuts, it grinds.  And have you ever lifted 50 pounds of it?! Imagine being a soft bodied annelid or a think shelled mollusk.  And being grated, smashed, and smooshed by the sand.

• Collection

• wait

• Box

• Tranship- in airplane

• Wholesalers- stored

• Fedex to you or stored

• Retail channels

Ways to Improve your Sand Bed:

• Add more benthic animals

Some sources may include Inland Aquatics Detrivore kits

         Indo Pacific Sea Farms shrimp cultures

         Brittle stars, Holothurians, worms, etc.

• Increase particle type diversity

                  Add more sand sizes

                  Add deeper sediment layers

• Add sifters

                  Gobies, other fish, etc.

• Feed and skimming

                  In established reef, can consider skimmerless operation

Heavy feeding of phytoplankton and zooplankton

                  Will help establish microfaunal population

• Depth

                  At least 6 to 8 inches. More if you can fit it.

                  Can be hidden with bottom.

Wentworth Geometric Scale
The phi scale is based on the logarithmic transformation of a particle diameter (phi = logbase2 particle size in mm)
	Particle Type	Size (mm)	Phi units
Gravel	Boulder	>256	beyond -8.0
	Cobble	256-64	-8.0 to -6.0
	Pebble	64-4	-6.0 to -2.0
	Fine Gravel	4-2	-2.0 to -1.0
Sand	Very coarse sand	2-1	-1.0 to 0
	Coarse sand	1-0.5	0 to 1.0
	Medium Sand	0.5 - 0.2	1.0 to 2.0
	Fine Sand	0.25 - 0.125	2.0 to 3.0
	very fine sand	0.125 - 0.063	3.0 to 4.0
Silt	coarse silt	0.063 - 0.020	4.0 to 5.0
	medium silt	0.020 -0.005	5.0 to 7.0
	fine silt	0.004 -0.002	7.0 to 8.0
Clay	clay	<0.004	beyond 8

Composition of Reef Sand Communities (Scoffin, et. al.,1985)
depth	region	composition
165 m	reef shelf edge slope	soft compacted sediment, medium to fine sand
98 m	shelf edge	medium to coarse compacted  sediments
71 m	outer shelf	coarse loose sediments, mainly Halimeda
63 m	inter-reef location 1	mixed sediment sizes
69 m	inter-reef location 2	soft loose fine sand
46 m	leeward reef talus	well worn coarse sediments
40 m	lagoon, near reef	coarse unsorted sand lagoon, away from reef medium to fine sediments with much macrolife