Flying Bear India Colors Imagination borrowed from Coral Reef Vegitation Under Sea World Cretures fr #1

Flying Bear India Colors Imagination borrowed from Coral Reef Vegitation Under Sea World Cretures from Caribbean Islands... more

by Navin Joshi

Title

Flying Bear India Colors Imagination borrowed from Coral Reef Vegitation Under Sea World Cretures fr #1

Artist

Navin Joshi

Medium

Mixed Media

Description

Flying Bear India Colors Imagination borrowed from Coral Reef Vegitation Under Sea World Cretures from Caribbean Islands

Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups.

Introduction

Coral reefs are complex mosaic of marine plants and animals. They are extremely rich in biodiversity supporting up to two million species and 25% of all marine life on the planet. As well as supporting these marine organisms, approximately 500 million people are dependent on coral reefs as a source of food, income and medicine. However, the future of coral reefs is in jeopardy as they have become threatened by human and natural disturbances which have already led to a loss of at least 19% coral reef areas since the 1950s.


Classification and anatomy

The term �coral reef� is commonly used when referring to large coral structures and the ecosystems that they support. Coral organisms, called polyps, are actually tiny invertebrate animals usually ranging from 1-3mm in size.

Coral polyps are classified as anthozoans within the phylum of Cnidaria. Anthozoans represent the largest class of organisms within this phylum and are characterised by a radially symmetrical body with a single opening (which serves as a mouth and anus) surrounded by tentacles. These tentacles contain venomous cells known as nematocyst and are used by the polyp to capture prey. The mouth of the polyp leads into the gastrovascular cavity, a simple sac-like stomach, where food is digested. The gastrovascular cavity, lined by the gastrodermis (stomach lining), is divided into a number of chambers by a series of the vertical plates (septum, pl. septa). These plates support the internal stomach folds, known as mesenteries, which increase the surface area of the stomach thereby aiding the digestion of food. The gonads of polyps are also found in the mesenteries.

The top of the coral is covered with a mucus layer. The outer tissue surface of the polyp that is in contact with the water is called the epidermis. Between this surface and the gastrodermis (stomach lining) lies the mesoglea, a jelly-like connective tissue. Each coral polyp is connected to its neighbour by the coenosarc tissue. This tissue also contains gastrovascular canals which allow coral polyps to share nutrients and in some cases zooxanthelle, a type of algae hosted within the gastrodermal cells of certain species of coral. This zooxanthelle creates a mutalistic symbiotic relationship with their host corals.


Hard corals (hexacorallia or hexacorals)

The tentacles, septa and mesenteries in hard corals appear in multiples of six hence the name hexacorals. Hard corals are commonly referred to as �reef builders� due to the calcium carbonate skeletons they secrete. The skeleton deposited by an individual polyp is known as a corallite. These skeletons, or corallites, are incorporated in the anatomy of coral polyps. For example, as a hard coral secretes calcium carbonate, a cup or calyx is produced, the walls of which are called theca. At the bottom of this cup is the basal plate tissue and it is upon this plate that the coral polyp sits.

Uploaded

March 28th, 2015