Exam #3 Flashcards
Anthozoan Characteristics
-solitary or colonial
-medusa stage is completely absent
-contains over 6,000 species
-all are marine
-sexual reproduction by fertilization
-asexual reproduction by transverse or longitudinal fission or by pedal laceration
-ciliated groove (1 or 2) called a siphonoglyph(circulation of water through the gv)
How do Anthozoans differ from Hydrozoans polyps?
-differs from Hydrozoans polyps because the mouth extends to a pharynx and then extends into mesenteries
Mesentries contain…
nematocysts ( in
hydrozoan polyps, there are no nematocysts in
the gvc)
General Characteristic of Subclass Zoantharia (Hexacorallia)
number of polyps are six or multiples of six
General Characteristics of Subclass Alcyonaria (Octocorallia)
-known as soft corals
-eight polyps, complete mesenteries, and 8 primary septa
-majority have no CaCO3
-body integrity is usually maintained by spicules or sclerites
-low wave action
-more dominant in high sediment areas
-more calcite production
Order Stolonifera Characteristics
-known as mat polyps
-possess tall or short retractible polyps connected by stolons
-the combined stolons form a network or solid mat
-mesentry is poorly developed
-some are able to actively feed
-five families
-diverse
-tubes resemble those of feather duster worms
-polyp have small sclerites for support
-depend on the uptake of DOM for nutrition
Family Clavularia
multiple polyps connected by stolons
Clavularia sp.
clove polyps
Calyx
polyp can retract into this
Stolon
rootlike runners from the polyps of certain soft corals that aid in substrate adhesion, asexual reproduction and inter-colonial communication
Family Tubiporidae Characteristics
-Belongs to order stolonifera
-has a well known dark red calcium skeleton that looks like an organpipe
-calcium carbonate crystal is calcite which are fused sclerites instead of being imbedded for stability
-hermatypic
Stolon plates
Green star polyps
-Stoloniferians
-Pachyclavularia violacea
Subclass Alcyonaria
Order Telestacea
Order Telestacea Characteristics
-Telesto, Carijoa - snowflake corals
-polyps bud side polyp branches
-polyps are small, cylindrical, very tall
-polyps connect at base and grow from a creeping stolon
-spicules may fuse to give rigidity
-can often be identified by color of calcium carbonate, depth and location
-found in areas of high turbidity
-considered a fouling organism
-azooxanthellate and eat DOM
Telesto riisei
often covered with encrusting thing like sponges
Subclass Zoantharia
-Order Zoanthidae
-Order Actinaria
-Order Scleractinia
-Order Corallimorpharia
-Order Ceriantharia
-Order Antipatharia
Subclass Alcyonaria
-Order Stolonifera
-Order Telestacea
-Order Gorgonacea
-Order Alcyonacea
-Order Coenthecalia
-Order Pennatulacea
Order Pennatulacea
Sea pens
Renilla
-primary polyp (base)
-secondary polyps or autozoids
-rachis
Order Pennatulacea Characteristics
-a colonial anthozoan with polyp dimorphism
-a central calcium carbonate rod
-largest is 2 meters
-bioluminscent
-can relocate
-14 families
Order Coenthecalia (Helioporacea) Characteristics
-Two families: each has one genus and one has only one species
-One of two Alcyonarians that are hermatypic
-Dominated in the Tethys sea (warm water) but isnt fairing well now probably (maybe in the future?)
-Inside has veins of a blue pigment that is actually biliverdin which it makes by taking iron from the water
The two Alcyonarians that are hermatypic…
stoloniferans, and coenthecalia
Order Gorgonacea
- includes whip corals, sea feathers, sea fans, and the precious red corals
- commonly tropical or subtropical
- have been proposed for hormone derivatives for the production of birth control, anti-inflammatory, anti-tumor properties
- highly represented in the caribbean
- the coenenchyme contains fused sclerites
- most are zooxanthellate
- feed on POM
- harbor symbiotic organisms
Suborder Holaxonia contains a central axial rod of … that is layered with…
gorgonin (proteins plus mucopolysaccharides), coenenchyme
Gorgoninians require a small surface area for … and large surface area for … ; therefore most are branching often in one plane with the broadest side perpendicular to the water current; branches may be connected by crossbars
attachment, feeding
Thinner, spindly-stiff gorgonians are found …, flexible branched gorgonians are found in …, intermediate stiffness in …
deeper, moderate surge, shallow waters
Gorgonians reproduction is sexual or asexual by …; Junceella sp. exhibts branchlet dropping
fragmentation
Corallum rubrum - red coral
- Red corals are found in the western Mediterranean and in the Adriatic, most often found in holes and crevices at depths up to 300 ft.
- In red coral, gorgonin is replaced by fused red spicules
Gorgonian Colony Forms
encrusting, unbranched, candelabra, branched, bushy, whip-like, reticulate, pinnate
Order Alcyonacea
- 31 families in order
- known as soft corals
- they resemble scleratinian corals with the rubbery coenenchyme acting as a substrate for the colony instead of the calcareous skeleton
- skeleton fused calcareous spicules embedded in coenenchyme
- largely tropical
- colony can be massive mushroom shape or encrusting form
- some are zooxanthellate but some such as Dendronephthya sp. lack zooxanthellate thus making their spicules obvious
Spicule
a small skeletal inclusion or calcium body that aids in supporting the body structure of soft corals; also called sclerite; aids in taxonomic distinction
Corallite
the skeleton secreted by a indivudual polyp; the basic unit of a stony coral
Corallum
the entire skeleton of a coral secreted by an entire colony
Calyx (calice)
the opening of a corallite or the rim of the cuplike structure; raised area into which the polyp may be withdrawn
Theca
the skeletal wall around the polyp
Coenosteum
skeleton between the polyps
Septa
vertical skeletal partitions dividing corallite into radial sections - speta project into the center of the calyx
Costa
when septa go outside the corallite
Columella
skeletal strucutre in the center of the corallite
Verrucae
small, cylindrical projections on skeletons, wart
Hexacorallia
Subclass Zoantharia
Order Actinaria
Sea anemones
Sea anemones are … and much larger than …
solitary polyps, hydrozoan polyps
Order Actiniaria Characteristics
-present in coastal waters throughout the world but more abundant in tropical waters
-live attached to the substrate or attached to jellyfish, ctenophores, and crabs
Body Shape of Actinaria
-Columnar shape with oral end and aboral end
-oral ends flares to form the oral disc which contians 8 to several hundred tentacles
-hydrostatic skeleton
-slit shaped mouth and ciliated groove (siphonoglyph) in oral disc
-upon contraction, a sphincter muscle contracts, the upper surface of the column is pulled over the oral disc
Gastrovascular cavity in Actinaria
–partitioned by radiating mesentries
-complete
-incomplete
-occur in multiples of 12
-mesenterial perforations in upper pharyngeal area help water circulation
Spirocysts
nematocyst, that have a sticky end for prey capture
Feeding in Actinaria
-some anemones feed on inverts, small fish, crabs; the prey is paralyzed by nematocysts, captures by tentacles, and carried to the mouth. the mouth is opened by radial muscles and prey is swallowed.
-others are suspension feeders - either cilia beat toward the oral disc or toward the tip of the tentacles; either way, tentacles finally sweep them into the mouths
Sea anemones have both …
commensal inverts and symbiotic zooxanthellae
Siphonoglyph
ciliated to aid in “swallowing, excretion, and water exchange”
Acontia
extensions of mesenterial filaments; has digestive function; can be used for aggression
Order Zoanthidae
-palythoa, zoanthus, epizoanthus, parazoanthus
-tentacles never pinnate
-zooxanthellae
-polyps may be solitary or colonial
-largely tropical and common reef inhabitants
-many are epizootic
-their oral disc is often very colorful
-commonly known as colonial anemones and button polyps
Palythoa
-Contains palytoxin, one of the most toxic non-protein, organic substances in the world
-tolerant to high sediment and high nutrient loaded areas
Ceriantharians
tube anemones, burrowing anemones
Ceriantharians Characteristics
-long, solitary elongated polyps
-they live in vertical tubes made of specialized nematocysts called ptychocysts
-prefer burrowing into soft mud or sandy substates with only their tentacles visible
-oral disk has two distinct whorls or tentacles; short labial tentacles and longer thin marginal tentacles, which are particularly well armed with nematocysts
-have only one siphonoglyph
-range is worldwide in tropical and subtropical areas
Order Antipatharia
black coral, thorn or wire coral
Antipatharia Characteristics
-used to be subclass ceriantipatharia
-thought to cure disease
-slowest growing corals
-colonial
-hawaii state gem
-tree like or stick like corals with a solid dark brown skeleton decorated with small spines or thorn
-rougher surface than gorgonians or hydroids
-polyp color gives colony a brown, yellow, green, orange, or white color
-feathery black coral has feather like branches
-most are deep water
-panglobal; most common in tropics
-common on vertical cliffs or rocky outcrops in deep water with high current
-low rates of recruitment but low natural adult mortality rate and long life
-colonies have tiny polyps that are ringed with six nonretractile tentacles that contain cnidocytes
-lack zooxanthellae so depend on suspension feeding
-provide critical habitat for other organisms
Antipatharia Reproduction
-delayed first reproduction
-asexually by budding or fragmentation
-dioecious or gonochoric
-broadcast spawning of gametes
-sexual maturity for a New Zealand species was estimated at minimum of 31 years
Order Corallimorpharia
mushroom corals, bullseye, giant elephant ear
-discosomatidae
-ricordeidae
-corallimorphidae
-sideractidae
Corallimorpharia Characteristics
-do not produce a calcareous skeleton
-solitary polyps (deeper water) but frequently colonial in shallow
-tentacles are knoblike and arranged radially on a flattened disc
-broad, flat top, attached to a substrate with a stalk
-can grow together in a mat-like arrangment
-some are large enough to eat fish
-contains zooxanthellae
-contain nematocysts
-may produce mucus nets or chemical defenses
-fluorescent or irredescent tentacles and oral disc
Corallimorpharia Reproduction
-asexually through budding, longitudinal fission, pedal laceration or polyp bailout
-not much is known about sexual reproduction
How to distinguish within Corallimorpharia
- Presence or absence of surface tentacles and shape (verrucae – short
tentacle; papillae -bumps) - Presence or absence of bare margins along the edge or oral disc
- Absence or presence of marginal tentacles
- Absence or presence of column and stiffness of base
- Ability to move and trap animal prey
- Maximum size
- Color
- Degree of colinality
- Absence or presence of spirocysts (sticky, non-penetrating
nematocysts)
Family Ricordeidae
- Short, berry-shaped tentacles
- Most common color is green
- Nematocysts and zooxanthellae
- Not as hardy as other mushroom corals
- Semi-aggressive
- Also eats small invertebrates
- Many are polystomatous
- Tentacles cannot be withdrawn
- Column is reduced or absent
Coral reefs are nutrient deserts - can zooxanthellae provide everything the corals need?
Zooxanthellae capture light and transfer energy to form sugars. Other nutrients must come from another source.
Most nutrient exchange takes place …
close to the reef
Definition of Biogeochemistry
the study of biologically mediated chemical compounds that influence geological processes
Nutrient concentrations are actually … on a reef and reflect the ocean around the reef
low
Biogeochemical pathways of a reef reflect those of a …
plankton system
Coral reefs show substantial rates of … but have no tendency toward exportation of nitrogen
nitrogen fixation, nitrification, and denitrification
Coral reefs are very efficient at recycling nutrients but the system as a whole is still …, but changes in nutrient input would change community structure
nutrient limited
… ecological efficiency is necessary to support the biomass of higher trophic levels
very high
Michaelis-Menton kinetics
theory of mass transfer, rate of enzyme reactions
… is taken up at mass transfer
limits. So actual net growth of a reef
community is controlled by mass
transfer of …
phosphate
Redfield ration
ratio of carbon, nitrogen and
phosphorus are pretty uniform through the oceans – 106:16:1
DON can be used to estimate coral reef …
metabolism
Low limiting nutrients but high primary production is a bit of a …
paradox
What recycles nitrates in corals?
zooxanthallae
What contributes to DON?
urea, amino acids, humic and fulvic substances, and nucleic acids
Turnover times and recycling of
nutrients is very rapid on coral reefs,
which also means that … is very rapid.
degradation
rate of organic matter
Calicoblastic epithelium
living tissue that is in contact with the calcium carbonate; also responsible for laying down additional skeleton
Desmocytes
bind the tissue to the skeleton
Cerioid
adjacent corallites shared fused walls
Plocoid
corallites have separate and well-defined walls
Dendroid
Appears to be a stem with buds
Phaceloid
tall, separate corallites rise up from the corallum
Flabellate
corallites form short valleys with separate walls
Meandroid
corallites are longitudinally fused to form sinuous hills and valleys
Hydnophorid
cone shaped protuberances between corallites
Thamnasteroid
plating coral with no walls surrounding to corallites
Massive
mounding; similar in all dimensions
Columnar
look like columns, straight up
Encrusting
grows ontop of a substrate
Branching
not parallel, branch out in every direction
Foliaceous
looks like a head of lettuce
Laminar
looks like encrusting, but edges do not stick to the rock
Turbinate
closed up, tight
Tabulate
flat, table-like
Solitary
fungia, move around
Order Scleractinia
-divided into 18 families, 11 of which contain hermatypic species
-most are zooxanthellate although there are a large number of azooxanthellate species
Family Acroporidae
- Extremity – porous
- Name comes from presence of corallite at the tip of each branch (terminal calex)
- No columella
- Most species rich family of reef building Scleractinia
- Most taxonomically difficult – Acropora robusta has different growth
forms in one colony - Tip of PNG and Irian Jaya is considered center of Acropora diversity
- All species observed were found to be hermaphrodites; majority are
broadcast spawners; some known to be involved in synchronous mass-
spawning events - Belize species – A. palmata (elkhorns); A. cervicornis (staghorn); A. prolifera
Two genera, … account for almost 1/3 of all hermatypic species
acropora, and montipora
Family Astrocoeniidae
- Aster – star; koinos – shared (ceroid)
- There are only 4 genera with 13 species (small
family) - Can be abundant on steep dropoffs because of
upwelling effect - Generally form large encrusting colonies
- Heavily temperature dependent
- Belize species – Stephanocoenia michelini – blushing star coral
Acropora cervircornis
Belize
Species; staghorn
Acropora prolifera
Belize species hybrid; almost
Horizontal branches
Acropora palmata
Belize species; elkhorn
Family Pocilloporidae –
cup/porous
- Indo-Pacific only
- Corallites are round to squarish in outline and well separated by
coenosteum - Corallites are immersed, well developed columella, and neatly
arranged septa - Coenosteum is covered with spinules (little spiny outgrowths)
- Usually branching
- Most common on reef flats and are often considered opportunistc
- Extremely polymorphic and growth morphologies depend on wave
action and light - First to colonize
- Mostly hermaphroditic
The second largest contributor to reefs…
family pocilloporidae
First largest contributor to reefs…
Acropora
Cnidocytes
cell type throughout the epidermis and are lodged in or are between epitheliomuscular cells, all are used once and released and then replaced; the actual firing mechanism is called a nematocyst or cnidae.
Nematocysts
-contain organelles called cnidae and the stining structure is called nematocyst
-cnidocil receives either chemical or mechanical stimuli
-operculum opens due to change in permeability of capsule
-base of cell is associated with epitheliomuscular cell and neuron terminal
Cnidae
-are used for prey capture and defense from predators
-contain organelles called cnidae and the stinging structure called the nematocyst
-cnidocil recieve either chemical or mechanical stimuli
-operculum opens due to change in permeability of capsule
-base of cell is associated with epitheliomuscular cell and neuron terminal
-nematocysts proper that penetrate and deliver toxins
Three types of cnidae
-true nematocyst
-spirocysts; found in anemone, mostly adhesive
-ptychocysts; pleated, form tubes of ceriantharians
Types of Nematocysts
Penetrant, glutiant, volvent
Penetrant
a harpoon-like structure used to penetrate, such as a nematocyst
Glutinant
a sticky surface used to stick to prey
Volvent
a lasso-like string that is fired at prey and wraps around a cellular projection on the prey, such as a spirocyst
Spirocysts
consist of a series of packed hollow tubes instead of bearing spines found in anthozoans
Stenotele - nematocyst of Hydra
delivers a toxin such as a neurotoxin, myotoxin, hemolytic, necrotic toxin
Desmonenes
nematocyst; no toxin, only wraps
Ptychocyst
material for a ceriantharian tube
Nematocyst discharge
-a trigger called a cnidocil sits on the exterior
-once the ciliaa of the cnidocil are contacted, the operculum f the cnidocyte opens
-the nematocyst capsule is under high pressure so when the operculum opens, the filament is thrown out at high speed
Toxins
- (1) catecholamines, (2) histamine, (3)
hyaluronidase, (4) fibrinolysins, (5) kinins,
(6) phospholipases, and (7) various
hemolytic, cardiotoxic, and dermatonecrotic
toxins. - All in all it disrupts neural activity and
degrades collagen
Family Euphyllia
- Means true leaf
- Prominent, leafy septa
- Common names – bubble, grape, frogspawn, hammer,
anchor - Zooxanthellate
- Colonies are phaceloid, meandroid, or flabello-meandroid
- Large, solid, widely spaced septo-costae
- Polyps are retractable and long
- Not hermatypic
- No Belize representation
Family Oculinidae
- Calices look like cats eye
- Striking colors
- Generously spaced corallites
- Fragile tubes
- Columella is weakly developed
- Septa extend above calyx giving a spiky appearance
- Both symbiotic and asymbiotic, hermatypic and
ahermatypic - Common names – diffuse ivory bush coral, delicate ivory bush, ivory tree coral
Coral Mortality
-physical damage
-sediment damage
-corallivores
-algal destruction
-disease
Physical damage
-storms
-boats
-diving
Sediment damage
-storms
-land-based runoff
-exposure
Corallivores
-Acanthaster planci (crown of thorns)
-Parrotfish
-Moorish idols
Black Band Disease
– Characterization – black mat a few millimeters wide on
the surface of coral tissue that slowly moves across
leaving behind bare skeleton; skeleton is then colonized
by filamentous algae
– Etiological agent (causes the disease) – Phoridium corallyticum – a filamentous cyanobacterium
– Death is caused by lack of oxygen and exposure to
hydrogen sulfide
– Infection is caused by stress due to sedimentation, high
nutrients, warmer temperatures
Etiological damage
-bacteria
-cyanobacteria
-fungis
-damage
SCTLD
stony coral tissue loss disease
White Band Disease - WBD
- Characterization – Type I – tissue peels or sloughs
off; Type II – a margin of disease bleaches before
dying - Etiological agent – Type I – unknown; Type II
various strains of Vibrio have been isolated but
none identified as causative agent - Found in Acroporids – Type II found only in
bahamas
Shut Down Reaction (SDR)
- Characterization – corals with an existing case of WBD begin sloughing off their tissue; disease spreads outward from a break in tissue; highly contagious
- Etiological agent – none known; acute or chronic stress related
- Rare in the wild; not always a recognized coral disease
Red Band Disease - RBD
- Characterization – soft microbial mat that is brick red or dark brown and is easily dislodged
- Etiological agent – cyanobacteria related
- Affects star and brain coral in Caribbean and star, brain, and staghorn coral in GBR
Rapid Wasting Disease - RWD
- Characterization – irregularly shaped patches of exposed white skeleton on star and brain coral, boundary between affected and normal tissue is fairly sharp
- Etiological agents – associated with male spotlight parrotfish and filamentous fungus
White Plague
- Type I – rapid loss of tissue from massive encrusting and branching corals; resembles WBD but at faster rate
- Etiological agent – WP I – none identified;
WP II – bacterium - WP I - world - wide
- WP II – Florida Keys
White Pox
- Characterization – patches of bare white skeleton on surface or underneath ledges
- Etiological agent unknown
- Found in Florida Keys
Yellow Blotch
- Characterization – irregularly shaped blotch of lightened yellow-colored tissue; as disease progresses, tissue in the center dies and fills with sediment and algae
- Etiological agent – unknown
- Found in Keys, Caribbean, Arabian Gulf (yellow band)
Dark Spot Disease
- Characterization – dark purple to gray or brown patches of discolored tissue; can cause tissue loss but coral can recover
- Etiological agent – unknown
- Found in Florida Keys and Caribbean in massive or lesser starlet corals
Tumors
-hyperplasia
-neoplasia
Hyperplasia
biological process that leads to an increase in the number of cells, increasing the bulk of a tissue or organ
Neoplasia
pathogenic process that results in the formation and growth of undifferentiated mass of cells
Coral immune system
- Phagocytes mostly – cells that attack invasive bacteria
- No humoral or immunocompetent cell types but evidence of evolutionary precursors
- They do have bioactive compounds
Family Siderastreidae
- Means star, star
- Regular star-like arrangement of calices and septa
- Colonies are massive or laminar
- Corallites are small, immersed and with numerous
thickened septo-costae - Septa are usually fused at inner margins
- Calyx walls are poorly defined
- Many corals have polygonal corallites
Family Agariciidae
- Means mushroom
- Common names – lettuce, sunray, scroll, saucer, elephant skin coral
- Massive or laminar colonies
- Corallites are modified and immersed with poorly defined walls
- Loosely packed septa have serrated margins
- Small to nonexistent polyps
- Dependent on zooxanthellae
Family Fungiidae
- Means mushroom
- Common names – razor coral, disk, tongue, plate, slipper
- Generally consisting of a single large polyp
- One of the most easily recognized
- Some can be colonial (polystomatous versus monostomatous)
- All fungiids go through an attached juvenile stage
- Septa-costae radiate from the mouth on upper surface as septa or underneath as costae
- Are capable of movement and righting themselves or digging out of sediment
- Mostly found on reef flats
- Atlantic species are azooxanthellae
Chemical Defenses in Scleractinians
-corals contain biologically active compounds
-they exhibit r-selection
Four levels of competition
Scleractinians
-behavioral
-morphological
-chemical allelopathy
-energetic
Behavioral competition
direct action by digestion, sweeper tentacles,
nematocysts, acrorhagi (mostly actinids; outgrowth of coelomic tissue that are specialized cnidocytes that contain nematocysts) and mucus production
Scleractinians
Morphological competition
overgrowth, oriented translocation, overtopping (coral growing ontop of other life), movement, and retreat growth
Scleractinians
Chemical allelopathy (secondary metabolics) competition
soliable compounds such as terpenoids, phenols, polyphenols, lipioids, diterpenes, amino acids, alkaloids, sterols, wax esters
Scleractinians
Energetic - physiological competition
loss or gain of energy due to conflict
Scleractinians
Sweeper tentacles
when a competing coral is chemically sensed, it will grow tentacles - specialized tentacles that take days or months to growth. this is considered both defensive move and an immunorecognition response with sspecificity, memory, and persistence. method of feeding, but primarily defense.
Scleractinians
Acrorhagi
are usually used against conspecifics and certain other cnidarians
Scleractinians
Oriented translocation
two colonies growing together or adjacent but ones does not overtly out-compete the other; it just makes it a slave and usurps its nutrients
Scleractinians
Chemoreception – immunity – ability to
fight off disease and to recognize “self
- Must be a method to recognize self or
foreign agents - A mechanisms to deal with foreign agents
must exist - inducible
Scleractinians
Settling cues
- Coralline red algae – lactosamine sulfate
- Coating of bacteria or other microbes
Scleractinians
Reproduction
process by which new individual are formed
Scleractinians
Recruitment
process by which newly formed individual become a part of the reef community
A reef can still die even if they are successfully reproducing…
if none of the new offspring are recruiting
Asexual Reproduction/Growth
– Intratentacular budding – one polyp divided into two polyps
– Extratentacular budding – a new mouth with tentacle can simply form in the space between two polyps
If polyps are tissue formed by asexual reproduction and remain part of the colony…
the result is considered growth
and is seen as an increase in colony size
If polyps or buds detach and gives
rise to a new colony it is considered…
asexual reproduction since it results
in formation of new individuals
Fragmentation
more common in finely branched or thinly plated coral – tissue and skeleton may become detached. If fragment manages to land on a solid bottom, it fuses and coninues to go through budding
Prop bailout
pieces of living tissue may leave underlying skeleton and swim through ciliary action to another area and settle and attach; also coral tissue may ooze out of a skeleton then differentiate into polyps and secrete a calcareous skeleton
Parthenogenesis
coral larvae may arise from unfertilized eggs; asexual brooding
Sexual reproduction
Gonochoric (dioecious) – separate
structures for separate sexes; identification of separate
sexes in corals is complicated by the fact
that females take longer to develop than
males; also, one colony may be gonochoric
and another colony of the same species may
be hermaphroditic
Hermaphordites
- Simultaneous – both ovaries and testes at the same time – most Acropora, Favia, Pocillopora
- Sequential – protandric – male first, then female; protogynous – female first, and then male – Stylophora, Goniastrea
Hermaphroditism is favorable in…
small populations
Brooding
(k strategists) eggs are fertilized internally and embryo develops into a planula stage inside coral polyp
Spawning
(r strategists) releasing of eggs and sperm into water column and fertilization takes place externally
Brooding vs. Spawning effect
- Transfer of symbiotic algae to larvae
- Larval competency
- Dispersal of larvae
- Biogeographic distribution patterns
- Genetic variability
- Rates of speciation and evolution
- Spawned gametes that float to the surface may be
affected by pollutants in the upper layers
Brooding Corals
- Larvae are immediately competent (capable of settlement and metamorphosis)
- Generally larger
- In hermatypic corals, contain full complement of zooxanthellae
- Usually results in planulae settling within centimeters of parent colony
- Brooders are sometimes called planulators
- Most participate in a mass multispecies spawning event that lasts 5-8 days in the early summer (May-June)
Spawning cues
- Water temperatures
- Illumination/tides
- Chemical cues (estrogens?)
Egg-sperm packets - spawning simultaneous hermaphrodites
- A cluster of 9-180 eggs surrounding a sperm packet
- Visible since eggs are colored (orange, pink, or red)
- Advantageous since eggs are buoyant due to high lipid
content and sperm is neutrally buoyant – this would
guarantee the sperm wouldn’t have to swim to the surface - At surface, a delay of 10-40 min. before they break apart and fertilization begins
- Delay increases chances of outcrossing and decreases
chance of self-fertilization
Barriers to self-fertilization
- Time dependent (six hours)
- Still less than 10%; outcrossing occurred 70-100% within two hours
- Chemical – cell-cell recognition (could be interfered with by chemical pollutants
Hybridization
- Does occur
- Usually unidirectional
- Could be deterred by timing of release
Cnidarians as clones
- Allows colony to maximize surface to volume ratio and grow larger
- What is an individual in a coral colony – a polyp, the entire colony or mulitple colonies that are genets? All – genet is genetically identical
Family Rhizangiidae
- Means root
- Polyps are linked by rootles
- Corallites are scattered, small and tubular
- Colonies are encrusting and plocoid
- Is often found on live rock
- Zooxanthellate
- Found only in Atlantic
- ahermatypic
Family Pectiniidae
- Means comb
- Calyx walls are thin and comblike
- Tall, thin, striated walls
- Usually laminar – on reef slopes – foliaceous
- Thick, fleshy polyps
- Possibly feed only at night
- Common names – lettuce, plate, elephant nose, scroll
Family Merulinidae
- Means pure line
- Line-like appearance of valleys
- Most powerfully aggressive with sweeping tentacles
- Some have conical structures called hydnae between
corallite centers - Zooxanthellate
- Found on reef slopes and lagoon
- Many varied growth forms
- polyps extend at night
- Common name – horn or ruffled coral
Family Dendrophylliidae
- Means branch and tree
- Colonies are solitary or colonial
- Mostly azooxanthellate
- Corallites are prominent and well separated
- Turbinaria only hermatypic species
- Have both pacific and Atlantic representation but no
Belize species - Genera Tubastrea has an antiviral agent called tubastrine
- Common names – sun coral, cup coral, turban, scroll
Family Caryophyllidae
- Knob-like polyps with leafy septa
- Diverse appearance but similar skeleton
- Both hermatypic and ahermatypic
- Both zooxanthellate and azooxanthellate
Family Mussidae
- Means mouse
- Large, single fleshy polyps
- Septa are toothed
- Sometimes contains some species of
Meandrinidiae - Common names – pineapple, doughnut, cactus
- 10 Belize species
Family Faviidae
- Means honeycomb
- Large, regular corallites
- Zooxanthellate
- Large corallites with strong walls
- Common name – brain or star corals
Family Trachyphylliidae
- Means leaf and looks like a large uneven
leaf - Solitary to colonial polyps – very fleshy
- “brain coral”
- No Belize species
- Trachyphylla
Family Poritidae
- Porous corallum
- Third largest contributor to reefs
- All genera are Pacific with Porites also found in Atlantic
- Massive, branching, laminar
- Corallites are usually compact with little to no coenosteum
- Patch reefs or lagoons
- Porites and Goniopora form large aggregates in turbid
coastal waters - Very fast growing
- Called finger coral
Heat-adapted clades of Zooxanthellae
- Symbiodinium Clades
– Clade – monophyletic group that is believed to be descended from a single ancestor
– Clade D – determined to be the most common high heat resistant clade of Symbiodinium
Genetically Engineered Corals
-GMO corals
-Symbiodinium is around 2 million base pairs: pretty big for a holobiont
Pigments
-Fluorescing proteins
-have been shown to be photoprotective
-work by absorbing and dissipating as well as reflecting light
Coral eating plastic
-coral select for and eat microplastics because they “taste good”
-it is still unknown what the breakdown products of the plastics will ultimately do to the corals
