Upload
others
View
8
Download
0
Embed Size (px)
Citation preview
Biology 105 Module 5 1
Module 5.The Coral Reefs of Florida
Coral Reef EcosystemsWhere are Coral Reefs?ResourcesEnergy Flow
Symbiotic AssociationsReef Ecosystem Problems
Changes in Resources, Changes in CommunitiesCoral Bleaching
World Distribution of Coral Reefs
Coral reef development is restricted to the low-latitude areas where watertemperature remains above 18oC (64oF). In each ocean basin, the coral reef belt iswider and the diversity of coral genera is greater on the western side of the oceanbasins.
wysiwyg://21/http://www.cgiar.org/iclarm/reefbase/frameg/rbmap.htm
Biology 105 Module 5 2
Coral Reefs in the United States
wysiwyg://21/http://www.cgiar.org/iclarm/reefbase/frameg/rbmap.htm
Coral Reef EcosystemsWave energy, light, salinity & temperature create zonation
concepts:• abiotic factors control community composition • temperature, salinity, wave energy, and light are major factors
controlling coral growth
Incidentlight
60%
20%
4%
Coralzonation
Massive branching corals dominatebuttress zoneMassive head corals grow in high energy zone
Delicate plate corals dominate wherewave energy in low
Where light is too low, no corals grow
Depth
20 m
50 m
150 m
island
lagoon
Biology 105 Module 5 3
BiodiversityThe high productivity of reef ecosystems fosters biodiversity
concepts:• high resource cycling leads to high productivity • high heterogeneity provides diverse habitats• reefs cover 0.2% of the ocean but contain 25% of ocean species
Symbiotic AssociationsForm the heart of a healthy coral reef
Polyps of a reef coral extend theirtentacles to capture tiny planktonicorganisms from the surroundingwater. However, for many reef-building corals, most of theirnourishment is provided bysymbiotic algae, zooxanthellae, thatlive in the coral tissue.
http://www.geology.iupui.edu/classes/g130/reefs/images/f1521ath.gif
Biology 105 Module 5 4
Symbiotic AssociationsCooperation between organisms enhances productivity
alga photosynthesis providesenergy source to coral (up to 90%)
coral provides a “home” andinorganic nutrients to alga
Threats to Coral ReefsLocal and distant activities affect reef health
pollution:nutrients & sediment
coastline development
coral harvest &indirect damage
fishing practice
concepts:• human activity directly & indirectly affects coral ecosystems• reef health is integrally linked to the health of other ecosystems
global warming
Biology 105 Module 5 5
Population Distribution - Florida
Coastal DevelopmentDamages coastal boundaries & alters land-sea interactions
Location: St. Augustine Inlet, Florida Photographer: Marge Beaver
Biology 105 Module 5 6
Mangrove Coastal BoundaryControls terrestrial-marine transfers
Red mangroveJohn PennekampState Park, Florida
Photographer: Richard B. Mieremet, NOAA OSDIA
concepts:• coastal mangrove forests filter water moving to sea• root systems provide habitat for fish, especially for reproduction
Seagrass BedsA critical and overlooked ecosystem
concepts:• seagrass beds filter water moving to sea• provide habitat and nursery ground for many species
Biology 105 Module 5 7
Changes in Resources ChangeCommunity Structure
nutrient levels in seawater
low
corals(symbiosis)
high
suspensionfeedersfleshy algae
phytoplankton
Nassau GrouperPredators control population dynamics
Epinephelus striatus, Nassau grouper
http://www.nova.edu/ocean/dna/picture.htm#Myinter
Biology 105 Module 5 8
Loss of Grazers or PredatorsChanges ecosystem balance
f-Sea urchins eat algae and keepcorals clean
Top predators may keeppopulations of coral-eatingstarfish in check
f-
algae corals thorn of stars grouper
sea urchin
Problems In The Florida Keys
• Loss of biological diversity• Too many algae• Decreased freshwater flow from
the Everglades to the Florida Baywhich has resulted in extremelyhigh salinity
• Increased ocean temperatures aredestroying the corals
• Rise in bleaching & black banddisease
Biology 105 Module 5 9
Coral BleachingChange in the physical environment eradicates zooxanthellae
Photograph of a bleaching hard coral (Goniopora sp) from Pohnpei, Micronesia.!Notice that the entire coral is not bleached, the polyps around the edges are stillhealthy. Photo taken by J Hoogesteger.
http://www.marinebiology.org/
Global Climate ChangeTemperature & CO2 are implicated in coral bleaching
surface temperatureCO2
Above 30oC,zooxanthellae nolonger fix carbon
Enhanced CO2dissolution acidifieswater, leading to coral degradation
concepts:• global change factors alter fundamental ecosystem variables• these changes act as selective forces against coral reefs