Seagrasses thrive in shallow, saline, and brackish waters worldwide, from tropical zones to the Arctic Circle. Resembling grass but botanically related to terrestrial flowering plants, seagrasses have roots, stems, leaves, and the ability to produce flowers and seeds, with an evolutionary history dating back around 100 million years. Despite their unassuming appearance, seagrasses play a crucial role as one of the planet's most productive ecosystems.

1. Welcome
to my Presentation

2. Presented by:
Humayun Kabir
2
Exploring Seagrass
Diversity:
Classification and
Various uses

3. Introduction:
Seagrasses thrive in shallow, saline, and brackish waters worldwide,
from tropical zones to the Arctic Circle. Resembling grass but
botanically related to terrestrial flowering plants, seagrasses have roots,
stems, leaves, and the ability to produce flowers and seeds, with an
evolutionary history dating back around 100 million years. Despite their
unassuming appearance, seagrasses play a crucial role as one of the
planet's most productive ecosystems.
3

4. 4
Characteristics Seagrass Seaweed
Classification Flowering plants Algae
Structure Has roots, stems, and leaves Typically lacks true roots, stems, or
leaves
Appearance Long, grass-like leaves Varied forms, can be filamentous or
leafy
Reproduction Produces flowers and seeds Reproduces through spores
Habitat Found in shallow salty and brackish
waters
Can thrive in various marine
environments
Ecology Forms underwater meadows
providing habitat and food for lots of
marine life
Important for marine biodiversity and
some species use it as a substrate
Picture
Seaweed
Seagrass

5. Where are Seagrass Found:
Seagrasses grow in salty and brackish (semi-salty) waters around the
world, typically along gently sloping, protected coastlines. Because they
depend on light for photosynthesis, they are commonly found in depths
of 1 to 3m, but the deepest growing seagrass (Halophila decipiens) has
been found at depths of 58m.

6. 4. Hydrocharitaceae
Enhalus
Halophila
Thalassia
2. Cymodoceaceae
Amphibolis
Syringodium
Thalassodendron
Cymodocea
Halodule
3. Zosteraceae
Phyllospadix
Zostera
Heterozostera
Seagrasses Biodiversity (Classification)
1. Posidoniaceae
Posidonia

7. 7
Family Image Genera Description Species
Zosteraceae
Phyllospadix The family
Zosteraceae
includes 2 genera
containing 14
marine species. It is
found in temperate
and subtropical
coastal waters,
highest diversity
located around
Korea and Japan.
P. iwatensis
P. juzepczukii
Phyllospadix scouleri
Phyllospadix torreyi
Zostera
Zostera angustifolia
Zostera asiatica
Zostera capricorni
Zostera chilensis
Zostera japonica
Heterozostera
H. tasmanica
H. polychlamys
H. nigricaulis
H. chilensis
Posidoniaceae Posidonia
Found in the seas
of the
Mediterranean and
around the south
coast of Australia.
P. angustifolia
Posidonia australis
Posidonia denhartogii
Posidonia kirkmanii
Posidonia ostenfeldii

8. 8
Family Image Genera Description Species
Cymodoceaceae
Amphibolis
The family
Cymodoceaceae,
also known as
manatee-grass,
includes only
marine species.
Some taxonomists
do not recognize
this family. Found
in tropical Indo-
Pacific (East
Africa, south
Asia and tropical
Australia to the
eastern
Pacific).
A. antarctica
A. griffithii
Syringodium
S. filiforme
S. isoetifolium
Thalassodendron
T. ciliatum
T. leptocaule
T. pachyrhizum
Cymodocea
C. angustata
C. nodosa
C. serrulate
Halodule
Halodule pinifolia
Halodule uninervis
Halodule wrightii

9. 9
Family Image Genera Description Species
Hydrocharitaceae
Enhalus
Also known as
tape-grasses,
include
Canadian
waterweed and
frogbit. The
family includes
both fresh and
marine aquatics,
although of the
16 genera
currently
recognised, only
3 are marine.
Enhalus acoroides
Halophila
Halophila australis
H. capricorni
Halophila decipiens
H. okinawensis
Halophila spinulosa
Halophila stipulacea
Thalassia
T. hemprichii
T. testudinum

10. Distribution of the Seagrass:

14. 1. Modification of the
Physical Environment:
 Seagrasses are known as
the "lungs of the sea"
because one square meter
of seagrass can generate 10
liters of oxygen every day
through photosynthesis.
3. Habitat and Nursery
Grounds:
 Seagrass meadows serve as
critical habitats for a
diverse range of marine
organisms, including fish,
crabs, shrimp, and juvenile
stages of many species.
2. Cultural and
Recreational Values:
 Seagrasses have cultural
significance in some coastal
communities.
 Recreational activities such
as boating, snorkeling, and
diving are often associated
with seagrass habitats.
4. Foundation of Coastal
Food Webs:
 Seagrass beds are
important feeding grounds
for thousands of species
around the world, and they
support this diverse food
web.
Benefits of Seagrass:

15. 5. Stabilization of Substrate:
 The extensive root systems
of seagrasses help stabilize
sediments and prevent
coastal erosion.
7. Nutrient Cycling:
 Seagrasses play a role in
nutrient cycling by taking
up and releasing nutrients
in the water.
 Seagrass leaves also absorb
nutrients and slow the flow
of water, capturing sand,
dirt and silt particles.
6. Blue Carbon:
 Seagrasses are effective at
sequestering carbon dioxide
from the atmosphere.
 Seagrasses are capable of
capturing and storing a
large amount of carbon
from the atmosphere.
8. Commercial and
Recreational Fishing:
 Seagrass habitats
contribute to the
productivity of fisheries,
supporting the livelihoods
of coastal communities.
Benefits of Seagrass:

16. 9. Water Filtration:
 Seagrasses help improve
water clarity by trapping
suspended sediments and
particles, contributing to
the overall health of coastal
ecosystems.
11. Research and Education:
 Seagrasses are subjects of
scientific research,
contributing to our
understanding of marine
ecology, physiology, and
coastal dynamics.
10. Bioremediation:
 Seagrasses have the
ability to absorb and
accumulate certain
pollutants, contributing
to the bioremediation
of coastal waters.
12. Erosion Control:
 Seagrass meadows act
as natural buffers
against storm surges
and wave action,
helping to protect
coastlines from erosion
and damage.
Benefits of Seagrass:

17. Conclusion:
In conclusion, the classification of seagrasses is a fundamental aspect
of understanding their diversity and ecological significance. By
delving into the taxonomic hierarchy and exploring key families and
genera, scientists and conservationists can work towards the
preservation of these critical coastal ecosystems. As we deepen our
knowledge of seagrass diversity, we enhance our ability to conserve
these vital components of marine environments.

18. References:
1. Seagrass Ecology by M. Hemming and C.M. Duarte
2. https://ocean.si.edu/ocean-life/plants-algae/seagrass-and-
seagrass-beds
3. https://en.wikipedia.org/wiki/Seagrass
4. https://ozcoasts.org.au/indicators/biophysical-
indicators/seagrass_species/
5. Butler, A.J. 1999. Seagrass in Australia: Strategic Review and
Development of an R&D Plan, FRDC Project 98/223.
https://www.frdc.com.au/project/1998-223

20. Questions
?