OtherBuilders
From coraldigest
Other Reef Builders like Hydrozoans, Sponges, and Algae
Outline For Expansions
- I. Hydrozoans
- A. Habitat
- Hydrozoans are found in all oceans, at all latitudes. Though most are found in salt water, some species inhabit fresh and brackish water on all continents except Antarctica.
- Hydrozoans are found in nearly all marine habitats, except for surf zones. Many species reside in warm, shallow, salty water, probably because of the availability of food in these habitats.
- B. Physical Traits
- Hydrozoan polyps are often symmetric, and can have a variety of shapes, including urn-shaped, conical, cylindrical, or club-shaped.
- Polyps can range from a few millimeters tall, to 2 meters tall, like Branchiocerianthus imperator
- At the base of many hydrozoan, there are hollow tubes, called stolons, which connect polyps in the same colony to each other, and allow for the transfer of food between polyps.
- Above the base is a ring of contractile cells called the sphincter, which can open and close as needed to isolate the polyp from the stolon, to prevent undigested food from entering the stolon.
- Many colonial hydrozoans are polymorphic, and have different structures for different functions. Some have large spiny tentacles for defense, some have tentacles and mouths for feeding, and #some have no mouth but reproduce in the form of producing medusae.
- As cnidarians, hydrozoans have cnidocytes. Cnidocytes, when prompted by a stimulus, shoot out of tiny hollow tubes in hydrozoans at high speed. Depending on the species of hydrozoan, these can be used to catch prey, fight off predators, or attach to a substrate.
- C. Colonial Development
- A founding polyp attaches to a substrate, and reproduces by budding to produce more polyps, to create a network of stolon, formed of living tissue, called the coenosarc.
- Some species form a single layer of polyps on top of substrate, while others will form stems of polyps coming off of the substrate.
- In the same way that colonial hydrozoans are polymorphic, so are the polyps that make them up.
- D. Reproduction
- Hydrozoans, in terms of reproduction, are mostly broadcast spawners, meaning they shed gametes. In the case of hydrozoans, they mostly shed sperm and retain eggs, and release sperm attracting compounds.
- It is not uncommon however for both eggs and sperm to be released by the hydrozoan into the water column, and for fertilization to occur externally.
- Polyps reproduce by budding, either creating daughter polyps, medusae, or both. In some species medusae will reproduce by fission or budding.
- E. Feeding Habits
- Feeding habits of hydrozoan vary greatly, with some trapping plankton with tentacles, some filter out food from the water column, and some using symbiotic algae.
- F. Sources
- http://animaldiversity.org/accounts/Hydrozoa/
- http://www.ucmp.berkeley.edu/cnidaria/hydrozoalh.html
- http://www.seawater.no/fauna/cnidaria/Hydrozoa.html
- II. Coralline Algae
- A. Description
- usually pink or red, can be other colors as well (gray, green, blue, yellow, purple)
- various forms
- branching (geniculate or articulated)
- encrusting (non-geniculate or non-articulated)
- classification
- Kingdom: Protista
- Division: Rhodophyta (red algae)
- Class: Rhodophyceae
- Subclass: Florideae
- Order: Corallinales
- Family: Coralinaceae (Coralline algae)
- B. Habitat/Location
- inhabit intertidal and subtidal coastal areas
- live on bedrock or other substrate
- also on other algae, on shells, in seagrass
- geniculate algae can be unattached
- live in range of light (depth of 0-270 m)
- can tolerate varying levels of water salinity
- do not live in freshwater
- popular for aquariums
- C. Biology
- sexual or asexual reproduction
- mineralogy: calcite (calcium carbonate,CaCO3)
- this compound sometimes contains Mg as well
- “fouling:” sloughing off outer layer of cells
- compete with algae attempting to grow on top of preexisting coralline algae
- eliminate burrowing organisms in outer layer
- renew damaged tissue and reproductive cells
- D. Ecology
- typically epiphytes
- promote herbivores and invertebrates
- algae produce chemicals that attract herbivore larval settlement
- provide habitat for small reef animals and invertebrates
- parrot fish and mollusks eat coralline algae
- calcite production binds reefs together
- crucial to the structure of reef systems
- E. Environmental Significance
- useful for fossil dating
- commonly found on reefs, but reefs are becoming endangered
- extracted for economic use
- geniculate algae are especially targeted
- used for soil conditioner, animal food additive, pharmaceutical products
- F. Sources
- Cabioch, J. "Morphogenesis and Generic Concepts in Coralline Algae — a Reappraisal." Helgoländer Meeresuntersuchungen Helgolander Meeresunters 42.3-4 (1988): 493-509. Web.
"Coralline Algae." Coralline Algae. California State University, Fullerton, n.d. Web. 01 Mar. 2016
- Johansen, H. William. Morphology and Systematics of Coralline Algae with Special Reference to Calliarthron. Berkeley: U of California, 1969. Print.
- Keats, D.w., M.a. Knight, and C.m. Pueschel. "Antifouling Effects of Epithallial Shedding in Three Crustose Coralline Algae (Rhodophyta, Coralinales) on a Coral Reef." Journal of Experimental Marine Biology and Ecology213.2 (1997): 281-93. Web.
- Martin, Sophie. "Marine Coralline Algae." Marine Coralline Algae. The Encyclopedia of Earth, 15 June 2014. Web. 01 Mar. 2016.
- Steneck, R. "The Ecology of Coralline Algal Crusts: Convergent Patterns and Adaptative Strategies." Annual Review of Ecology and Systematics 17.1 (1986): 273-303. Web. 1 Mar. 2016.
- Woelkerling, W. J. M.H. Foslie and the Corallinaceae: An Analysis and Indexes. Vaduz: J. Cramer, 1984. Print.