Mangroves, Salt Marshes, and Deep Water Habitats

1. Mangroves, Salt Marshes, and Deep Water Habitats February 16th, 2011 Brittanica.com

2. Mangrove Swamps • Also known as tidal forests • Have received inadequate attention until recent years

3. Mangroves • Worldwide distribution • Between 250 North and 250 South latitude • 75% of coastline in this area has mangroves • 25% of all Caribbean coastline has mangroves Mangrove Distribution

4. Mangrove and Reef Distribution Mangrove Distribution Coral Reef Distribution

5. Environmental Conditions • Mangroves are rooted in anoxic sediment • Belowground tissue is subjected to long periods of anaerobic conditions • Slows nutrient uptake • Allows for accumulation of toxins • Mangrove tissue is also exposed to decomposing bacteria

6. Environmental Conditions • Few plant species grow in highly saline environments • Those that can are called halophytes • Less than 2% of all plant species are halophytes • Only 110 sp. of mangroves in the world • Mangroves transpire less than other plants, must find a way to conserve water • Vadose layer of soil

7. Adaptations to environment • Anoxic sediment • Broad roots, shallow depth • Root extensions that project into the air • Root strategies • Root props • Knee roots • Finer roots

8. Adaptations to the environment • Salt excluders • Ultrafiltration systems • Store Na+ in vacuoles • Salt excreters • Salt glands

9. Zonation • Vertical zonation in mangrove species distribution • Red- Extend into water • Black- Inundated at high tide • White- Above high tide line

10. Red Mangroves • Rhizophora mangle • Most swamps are dominated by it • Extend into water • Able to grow roots completely submerged in seawater • Extensive prop root system • Salt excluder - membrane at root surface • Leaves with waxy coating • Promotes siltation by slowing wave action • Promotes island building

11. Red Mangroves

12. Black Mangroves • Avicenniagerminans • In areas not underwater all of the time, only during high tides • Soil is very saline and low in oxygen • Have vertical pneumatophores in root system • Extend above ground • Allows them to get oxygen from air • Secrete excess salt from leaf glands as crystals • Waxy coating

13. Black Mangroves

14. White Mangrove • Lagunculariaracemosa • Found only above high tides • Soil is very muddy and water-logged or can be sandy • Can not stand high moisture levels (like the first two species) • Tolerant of high levels of salt • Salinity usually increases towards shore • Salt excretion via leaf glands

15. White mangroves

16. Zonation in Mangrove Swamps in Jamaica (Warner 1968) • Five Zones: • 1. Fringe Zone • 5% of total swamp • In water • Pure stands of red mangrove • 2. Red Mangrove Zone • 20-25% of swamp • Closed growth, tangled mesh of prop roots • Pure stands of red mangrove • 3. Transitional Red and Black Zone • 5-10% of swamp • Dominated by red mangrove, but with black mangrove present

17. Zonation cont. • 4. Mixed Red, Black and White Mangrove Zone • 40% of swamp • Less than half are red mangrove • The rest are black and white mangroves • 5. Back Zone • 15% of swamp • Dominated by black and white mangroves

18. Functions • Important ecological bridge between land and sea • Provide protection of land during storms

19. Functions • Important ecological bridge between land and sea • Provide protection of land during storms • Trap nutrients to help productivity of surrounding sea • Trap sediments that would kill coral populations

20. Functions • Important ecological bridge between land and sea • Provide protection of land during storms • Trap nutrients to help productivity of surrounding sea • Trap sediments that would kill coral populations • Provides nursery areas for many juvenile reef fishes

21. Animals of the Mangrove Community • Prop roots of red mangroves provide substrate for benthic organisms (algae, sponges, hydroids, tunicates) • Mangrove swamps provide critical protected nursery areas for fishes, crustaceans, and shellfish.

23. Impacts of Mangroves as Nurseries • Very few reef species dependent on mangroves • Some are dependent: Goliath grouper, Rainbow parrotfish • Presence of nearby mangroves does not impact total reef species diversity • Total fish biomass significantly impacted by presences of nearby mangroves • (up to a 25X increase) Lutjanidae Haemulidae

24. Impacts of Mangroves as Nurseries • Rainbow parrotfish- Scaridae • Largest herbivore in Atlantic Ocean (over 1.2 m) • Juveniles dependent on mangroves • Heavily influence physical structure of coral formations • Coral structure = coral community structure

25. Threats to Mangroves • More than half of world’s mangroves have been eliminated • Deforestation for shrimp farms • Loss of invertebrate food for fishes • salinization of freshwater • Leads to decline in coastal fisheries • Documented in Thailand • Antibiotics into oceans *Current rate of mangrove destruction exceeds that of rain forests (~900 sq. mi. per year)

26. Threats to Mangroves

27. Threats to Mangroves • Global climate change • Storms cause seawater to enter freshwater systems • Flooding • Hypoxia • Salt-stress • Loss of plant biodiversity • Less protection from hurricanes

28. Salt Marshes • Also known as tidal marshes, temperate equivalent of mangrove forests • Associated with estuaries • Common along Atlantic and Gulf coasts

29. Salt Marshes • Muddy bottom held together by roots of marsh plants • Includes creeks and mudflats • Experience extreme salinity, temperature changes, and tides

31. Salt Marshes- Zonation • Similar to mangroves • Varies due to height relative to tide, geographical location, type of substrate • Most common plants: Cordgrasses • Stabilizes soil

33. FIG. 14.34 The aerenchymal tissue allows Spartinato exchange gases, even when surrounded by an anoxic soil. The tissue in this photograph is visible as a series of circular passageways around the periphery. (Photograph courtesy of Mark Bertness.)

34. Salt Marshes- Conservation • Salt marshes are overfished for benthic inverts • Trophic cascades • Human dredging for development

35. Deep Water Habitat • 84% ocean lies deeper than 2000 m • Deep-sea bottoms are mainly sand and mud, but populations exhibit high level of patchiness • Bottom currents • Larval settlement • Animal modification of sediment

36. Deep Water Habitat • Organic matter supplied from primary producers in surface waters • Only 2-7% of surface production reaches bottom of North Atlantic gyre • Carnivores become less abundant

37. Adaptations to the Deep Sea Gulper eel • Low food supply • Sluggish fish, low muscle mass • Low metabolic rates • Predators with large mouths and stomachs • Long guts • Low/no light • Large eyes • Eye placement Barreleyes

38. Deep sea biodiversity • Stable environment • Sheer area • Larger number of species relative to continental shelf bottoms • Difficult to sample

39. Deep water coral mounds • From 30 to 1000+ m deep • Hard coral (without zooxanthellae), sea fans, sea whips • Over 2000 spp. • Demersal fisheries

40. Leiopathes sp. • Black coral • Oldest living organisms in sea? • Over 2000 years old

41. Deep sea vents • Hot vents are located near areas of submarine volcanic activity • Spew out sulfide-rich water

42. Deep sea vent biodiversity • Large tubeworm Riftiapachyptila • Bathymodiolusthermphilus Whoi.edu

43. Deep sea vent biodiversity • Photosynthetic anaerobic bacteria • Oxidizes S to obtain CO2 • Has photosynthetic pigment that absorbs energy from geothermal radiation • Taq polymerase