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Understanding Coral Reefs

Silica13ron — Tue, 19 Mar 2013 04:30:03 GMT

Silica13ron:

[http://blog.stevenwsmeltzer.com/what-are-coral-reefs/introduction-to-the-underwater-world/ What Are Coral Reefs] - Learning about Coral Reefs
[http://blog.stevenwsmeltzer.com/what-are-coral-reefs/ Coral reefs] are made up of thousands and thousands of tiny marine creatures which are in the class anthozoans, the largest class of organisms within the phylum cnidaria (the "c" is silent). Cnidaria has more than 6,000 recognized species of sea fans, sea pansies, jellyfish, and sea anemones. Corals, subsequent to their larvae stage, no longer move but are fixed in one place. This type of animal is called a sessile animal.

[http://www.stevenwsmeltzer.com Coral reef] colonies are made of millions of these tiny, cup-shaped creatures termed polyps. A single coral polyp may be as large as a saucer or smaller than the head of a pin. Millions of polyps working in concert in a collaborative colony generation after generation make the limestone skeletons that create the framework of the magnificent coral reef. Coral reef colonies reproduce both sexually and asexually. In sexual reproduction, the coral polyps release both eggs and sperm into the water. (This is also called coral spawning.) One kind of asexual reproduction occurs when fragments of coral are broken off because of storm action. The broken pieces of corals more often than not live and continue to grow and produce a new colony. This method is known as "fragmentation". Corals live in colonies consisting of numerous individuals, each of which is called polyp. They produce a hard calcium carbonate (rock-like) skeleton, which serves as a uniform foundation or substrate for the colony. This skeleton enables two fundamental functions, first for the coral itself it provides safety, as the polyps can contract into the structure if predators draw near and second this same skeletal structure is what makes up the coral reefs over a period of time. The calcium carbonate is produced at the base of the polyps, so the living portion of the coral colony occurs at the exterior of the skeletal structure, totally covering it. The calcium carbonate deposited by the colony incessantly adds to the size of the overall structure and thus the enlargement of the reef. The expansion of these reef structures varies greatly, depending on the species of coral and environmental conditions-- ranging from 0.3 to 10 centimeters per year. The skeletons of stony corals are secreted by the lower part of the polyp. This process creates a cup, called the calice, in which the polyp is located. The walls surrounding the cup are called the theca, and the floor is called the basal plate. Thin, calcareous septa (sclerosepta), that provide structural integrity, protection, and an increased surface area for the polyp's soft tissues, extend upward from the basal plate and radiate inward coming from its outer wall. Periodically, a polyp will raise up off its base and secrete a new floor to its cup, forming a new basal plate above the old one. This creates a tiny chamber in the skeleton. When polyps are physically stressed or under impending attack, they contract into the calice so that practically no part is exposed above the skeletal platform. This protects the creature from predators and the elements (Barnes, R.D., 1987; Sumich, 1996). Different species of coral construct structures of various dimensions and shapes such as brain corals, fan corals, encrusting corals, etc., producing incredible variety and complexity in the coral reef ecosystem. Various coral varieties tend to be segregated into characteristic zones on a reef, separated out by competition with other varieties and by environmental conditions. Corals have only a limited level of organ development and consists of three fundamental tissue layers: an external layer or epidermis, an inner layer of cells lining the gastrovascular cavity (an internal space for digestion) and a layer called the mesoglea between the other two layers Barnes, R.D., 1987. Corals feed by reaching out by means of tentacles to catch quarry like small fish and planktonic creatures (any drifting organisms, animal, plant, archaea or bacteria that inhabit the pelagic zone of the oceans). See Also: Creatures of the Coral Reefs Resources: Marine Species Galleries: Coral Reef Images Pictures of Fish Sea Turtles Crustaceans and Echinoderms Moray Eels Detailed Information on select Marine Species: Caribbean Fish Hawaiian Fish Sponges Crustaceans, Invertebrates, Mollusks, Echinoderms

Underwater Digital Cameras

Silica13ron — Sun, 17 Mar 2013 02:25:41 GMT

Silica13ron:

I recommend exploring a number of important features including lens speed or the "f-stop" rating. The faster the lens., e.g., the lower the f-stop number the better and the more light that the lens permits into the digital camera making higher qualtity less noisy images. f2.0 is very fast and f3.9 is ok, although it will have more difficulty in situations where the lighting is low and can typically be more difficult to focus in lower light situations. An additional attribute is the capability of the zoom lens and how much of the "zoom" is created by the lens compared to a digital zoom, where a software program is generating the zooming effect. Another feature for taking pictures close up is the capability to take macro shots and how close to the subject matter you may get the camera and still focus. One other characteristic to consider would be the capability to shoot video and the video processors speed, e.g., is the video processor high speed meaning it will capture over 200 frames per second (fps), or else does it have a low speed video processor. A faster vidwo processor will create higher quality videos.

The evaluations of the waterproof digital cameras listed below gives a good synopsis of a number of of the leading point and shoot water-resistant cameras along with a suggestion on the best camera.

Water-resistant cameras reviewed:
<ol>
<li>Panasonic Lumix TS4 12.1 TOUGH Waterproof Digital Camera with 4.6x Optical Zoom
<li>Nikon COOLPIX AW100 16 MP CMOS Waterproof Digital Camera with GPS and Full HD 1080p Video
<li>Canon PowerShot D20 12.1 MP CMOS Waterproof Digital Camera with 5x Image Stabilized Zoom 28mm Wide-Angle Lens a 3.0-Inch LCD and GPS Tracking
<li>Fujifilm XP170 Compact Digital Camera with 5xOptical Zoom Lens
<li>Olympus Stylus TG-830 iHS Digital Camera with 5x Optical Zoom and 3-Inch LCD
<li>Pentax Optio WG-1 Adventure Series 14 MP Waterproof Digital Camera with 5x Wide-Angle Optical Zoom
<li>Olympus TG-1iHS 12 MP Waterproof Digital Camera with 4x Optical Zoom
</li>
</ol>

In case you are willing to spend about $1,000 to obtain the [http://www.squidoo.com/best-waterproof-point-and-shoot-camera finest waterproof point and shoot camera] setup then one of the best underwater cameras in the extreme digital camera market is positively the Olympus TG-1 iHS. This camera when bought with the optional Olympus underwater case and strobe allows the diver to take pictures in over 130 feet of water and also makes a very decent beginning level underwater camera for any diver. ntire expenditure includes the camera, a rugged housing that enables the diver to take the camera to a depth of 135 feet and an independent strobe that delivers the capability to photograph in a varity of different situations.

Wreck diving Grand Cayman - USS Kittiwak

Silica13ron — Thu, 14 Mar 2013 07:47:08 GMT

Silica13ron:

This is the top wreck dive in Grand Cayman and one of the top ten in the Caribbean. The USS Kittiwake has been on the reef for a about 18 months ago and the shipwreck site is maturing well. The shipwreck has five decks, is 251.6 ft (76.7 m) in length, 42ft (12.8 m) in beam and about 50 feet high. The ship was designated for submarine rescue and was launched on July 10, 1945 and she was reefed in Grand Cayman in January 2011.

The following is an overview of the dive, some history and information regarding the ship and an overview of what one can find on the shipwreck. Review the complete [http://stevenwsmeltzer.com/gallery/Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/ photo gallery] on the website and/or see the blog article for the [http://blog.stevenwsmeltzer.com/dive-site-reviews-and-listings/dive-sites/scuba-diving-grand-cayman-uss-kittiwake-shipwreck/ USS Kittiwake] for supplementary data on the shipwreck and a history about the ship.

The Dive:

The ship was reefed In january 2011 off the west side of the island at the end of Seven Mile Beach in Grand Cayman.

There are 5 decks on the 47 foot tall [http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000Wcb0w0RopvI USS Kittiwake]. Externally, the crow's nest, mast and large stern a-frame have been cut down and remounted to make her height suitable for Cayman waters. The are two bridges on the upper decks along with the radio and navigation room. The has also been removed from the ship. The Captain and executive officer's quarters are also on the upper decks.

On the main deck, from bow to stern, internally you will find the rec room, mess hall, ironing room, small tool workshop and recompression chambers.. You will note the large [http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000nrOSPnFJRtU a-frame structure] on the stern that rescue divers, along with the diving bell where divers would enter to return to the ship from the ocean and then be placed in the chambers for decompression.

Below the main deck, 2 decks exist that include the crews quarter, medic/hospital station, engine and propulsion rooms,[http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000QmV9jUuDJyQ air bank storage] and compressors, as well as ammunition lockers, cold storage, barber shop and other areas. While the USS Kittiwake has been opened up with large[http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000evHtkg3GaYQ access holes] both vertically and horizontally, all of the space on the vessel was used when the boat was in service.

Make sure to chart your dive adequately. One approach would be to begin at the stern before entry into the vessel to get photographs near the[http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000MlfKl.47lgI "USS Kittiwake" logo] on the stern and in addition get photographs by the propeller. For Scuba Divers that plan on entering the shipwreck, after you leave the stern make your way to the top of the ship then enter via the funnel which is on on the Top Deck. If you do not intend on entering the shipwreck you may begin your investigation of the ship on the deck just above the Screw..

The main [http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000ndu7PcxF.bM entry through the funnel can be a great location for underwater photography] . try silhouetting your dive partner in the shaft diving down into the shipwreck. You can exit into the ship on several of the decks including the first platform or in the cargo hold. The cargo hold should only be entered by experienced advanced divers. On the first platform you can see the Engineering emblem in the Motor Room section. This area is easily accessible and can be the subject of a very good underwater photograph close to the "[http://stevenwsmeltzer.com/gallery-image/USS-Kittiwake-Grand-Cayman/G0000JtpXOPWAQac/I0000Y0UeUwX5JJc Engineering Mural]". The silt may be heavy in this location so you must move gradually to prevent stirring up the sediment. For advanced wreck divers you can also explore shaft alley as well as the front hold sections of the ship. For others you may check out the various areas on the first platform and after that begin making your way up one deck at a time until finally coming to the Bridge (Pilot House) where you can do you safety stop as it is at about 5 to 6 meters or 15 to 18 feet.

Check out photos of additional [http://stevenwsmeltzer.com/gallery/Shipwrecks/G0000OtMyTETA74I/ shipwrecks] on http://www.stevenwsmeltzer.com or visit his [http://blog.stevenwsmeltzer.com/dive-site-reviews-and-listings/dive-sites/scuba-diving-grand-cayman-uss-kittiwake-shipwreck/ blog] for evaluations of specific wrecks.