The effect of water flow rates on cover and diversity of macroalgae and coral on patch reefs in Glov

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The effect of water flow rates on cover and
diversity of macroalgae and coral on patch reefs
in Glovers Reef, Belize

• Emily Seidman
• Columbia University
• Ecology, Evolution and Environmental Biology
• Mentor Tim McClanahan, WCS

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Glovers Reef Marine Research Station

• 260 square km coral atoll
• 30 km east of Belize
• 850 patch reefs
• Designated a Marine Reserve
• Conservation Zone
• General Use Zone

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Coral Reef Biology

• Corals live in shallow, clear, warm waters.
• Feeding is aided by symbiotic relationship with
  zooxanthellae (microalgae) that live in epidermis
  of coral polyp.

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Coral Reef Degradation

• 1970-71 80 live coral, 20 algae
• 1996-97 20 live coral, 80 algae
• Possible causes
• Bleaching events, coral diseases
• Over-fishing
• Diadema antillarum die off
• Pollution, other anthropogenic forces

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Is water current flow rate a determining factor
in the health of a coral reef?
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Previous Research on Water Flow Rates

• Research performed from 1970s to the present has
  found
• Increase in flow rate leads to increased oxygen,
  carbon dioxide and nutrient flux in and out of
  coral, especially zooxanthellae
• Leads to increased respiration rate and faster
  growth
• Coral and algae both benefit from these advantages

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Measuring Water Flow RateClods

• Clods are
• Ice-cube shaped molds of plaster
• Glued to 3 in 3 in plastic cards
• Weighed on triple-beam balance prior to use
• Attached with wire to leeward side of patch reefs
  throughout the atoll GPS location recorded
• Left for 48 hours in the water
• Dried for 24 hours after removal
• Weighed on triple-beam balance after use
• Used in triplets to control for inconsistencies

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Benthic Coverage Data

• In 2000-2001, Dennis Thoney (WCS) collected data
  throughout Glovers Reef Atoll on the benthic
  make-up of the patch reefs.
• Collected data by lying 4 randomly placed lines
  across the patch and recording the species of
  coral, algae, invertebrate or other object and
  the length covered by that species.
• Combined the data from 2000 and 2001 into one
  large data set and combined the 4 surveys from
  each patch reef into one data set per GPS
  location.

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Coral and Algae CoverLatitude
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Coral and Algae DiversityLatitude
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Current SpeedLatitude
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Future Data Analysis

• Use GIS to accurately match current speed and
  coral and algae cover and diversity
• Perform statistical testing on coral and algae
  cover and diversity data
• Perform statistical analysis on current speed and
  coral and algae cover and diversity results to
  determine the extent of the relationship

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Implications of Research

• Information can be used to determine what areas
  of reefs should be set aside as marine reserves
  based on current flow rate and coral health

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Acknowledgements

• I would like to thank
• Tim McClanahan, WCS
• Don Melnick, EEEB, Columbia University
• Brie Cokos, CC 01
• WCS GRMRS Staff