1. Seagrasses: UnderwaterSeagrasses: Underwater
Food FactoriesFood Factories
A Tampa Bay ExampleA Tampa Bay Example
of a Food Webof a Food Web
Prepared by:Prepared by:
NOE P. MENDEZNOE P. MENDEZ
CENTRAL MINDANAO UNIVERSITY (CMU)CENTRAL MINDANAO UNIVERSITY (CMU)
npolomendez@gmail.comnpolomendez@gmail.com

2. Seagrasses: So What Are They?Seagrasses: So What Are They?
 Seagrasses areSeagrasses are
flowering underwaterflowering underwater
plantsplants
 Found at shallowFound at shallow
depths in estuaries:depths in estuaries:
bays and lagoonsbays and lagoons
with good waterwith good water
qualityquality
 What are someWhat are some
reasons that thesereasons that these
plants can grow onlyplants can grow only
in shallow water?in shallow water?
Source: http://tbep.org/portrait/habitats.html
Flowers
Leaves
Rhizome
(underground stem)
Line drawing of Manatee grass
(Syringodium filiforme)

3. They grow in shallowThey grow in shallow
water because...water because...
 Seagrasses require good water clarity andSeagrasses require good water clarity and
quality to survive.quality to survive.
 They possess structures similar toThey possess structures similar to
terrestrial plants like roots, leaves andterrestrial plants like roots, leaves and
flowers.flowers.
 They need sunlight to penetrate the waterThey need sunlight to penetrate the water
in order to perform photosynthesis.in order to perform photosynthesis.

4. 3 Types of Seagrasses in3 Types of Seagrasses in
Tampa BayTampa Bay
 turtle grassturtle grass
(yes, sea turtles eat it!)(yes, sea turtles eat it!)
 shoal grassshoal grass
(usually the first(usually the first
species to appear)species to appear)
 manatee grassmanatee grass
(yes, manatees love it!)(yes, manatees love it!)
Pictures from
http://www.dep.state.fl.us/coast
al/habitats/seagrass/awareness
/healthy_images.htm

5. So, Why are Seagrass BedsSo, Why are Seagrass Beds
Important?Important?
 As a nursery environment, seagrassesAs a nursery environment, seagrasses
support small fish, shrimp, and crabs thatsupport small fish, shrimp, and crabs that
hide among the blades and feast onhide among the blades and feast on
decaying leaves.decaying leaves.
 They help stabilize shifting sands on theThey help stabilize shifting sands on the
bottom of the bay.bottom of the bay.
 They improve water clarity by trappingThey improve water clarity by trapping
fine sediments and particles.fine sediments and particles.

6. The Decline of Seagrass BedsThe Decline of Seagrass Beds
 After 1950, the seagrass beds in TampaAfter 1950, the seagrass beds in Tampa
Bay seriously declined.Bay seriously declined.
 The major reason for decline in seagrassThe major reason for decline in seagrass
beds is probably water pollution.beds is probably water pollution.
 As a class, list reasons why waterAs a class, list reasons why water
pollution in Tampa Bay would increasepollution in Tampa Bay would increase
after 1950.after 1950.

7. Reasons Why Water PollutionReasons Why Water Pollution
Would IncreaseWould Increase
 Population increased; more garbage, sewage dumpedPopulation increased; more garbage, sewage dumped
into bayinto bay

More people lived near the Bay; more workplaces builtMore people lived near the Bay; more workplaces built

More cars, trucks -- air pollution (mercury, NOx, lead ends up inMore cars, trucks -- air pollution (mercury, NOx, lead ends up in
water)water)
 Oil, gasoline spills from cargo shipsOil, gasoline spills from cargo ships
 Port of Tampa receives more cargo ships (sewage,Port of Tampa receives more cargo ships (sewage,
garbage and fuel spills from ships)garbage and fuel spills from ships)
 More nitrogen entered the bay:More nitrogen entered the bay:

Sewage treatment plants were not like today (untreated sewageSewage treatment plants were not like today (untreated sewage
common in bay)common in bay)

Industries dumped chemically polluted waste directly into waterIndustries dumped chemically polluted waste directly into water
 No real government control of water pollution beforeNo real government control of water pollution before
19721972

8. Compare the Seagrass BedsCompare the Seagrass Beds
40,420 ac in 1950 26,920 ac in 1996

9. A Big ImprovementA Big Improvement
 Improvements in water quality have fueledImprovements in water quality have fueled
steady gains in seagrass recoverysteady gains in seagrass recovery
 Tampa Bay is now gaining about 500Tampa Bay is now gaining about 500
acres of seagrass a year, and has aboutacres of seagrass a year, and has about
29,647 acres baywide as of 200829,647 acres baywide as of 2008
 The goal is to getThe goal is to get
to 38,000 acresto 38,000 acres

10. Seagrass Change Through TheSeagrass Change Through The
YearsYears

11. Life in a Tampa Bay Seagrass BedLife in a Tampa Bay Seagrass Bed
 Bacteria, FungiBacteria, Fungi
 AlgaeAlgae
 InvertebratesInvertebrates
 FishFish
 ReptilesReptiles
 BirdsBirds
 MammalsMammals

12. Life in a Tampa Bay Seagrass BedLife in a Tampa Bay Seagrass Bed
 Bacteria, FungiBacteria, Fungi

Decompose seagrass leavesDecompose seagrass leaves
 AlgaeAlgae

Grows on seagrass leaves, becomes detritusGrows on seagrass leaves, becomes detritus
 InvertebratesInvertebrates
 FishFish
 ReptilesReptiles
 BirdsBirds
 MammalsMammals

13. Life in a Tampa Bay Seagrass BedLife in a Tampa Bay Seagrass Bed
 Bacteria, FungiBacteria, Fungi
 AlgaeAlgae
 Invertebrates – scallops, crabsInvertebrates – scallops, crabs
 Fish – snook, sharksFish – snook, sharks
 Reptiles – sea turtlesReptiles – sea turtles
 Birds – wading birdsBirds – wading birds
 Mammals - manateesMammals - manatees

14. THANK YOUTHANK YOU
FORFOR
LISTENING!LISTENING!
NOE P. MENDEZNOE P. MENDEZ
Central Mindanao UniversityCentral Mindanao University
npolomendez@gmail.comnpolomendez@gmail.com