Dr. Jose Antonio Guntalidad

Spatial Variation In The Geophysicochemical
And Biological
Characteristics Of Seagrass Beds in
the Intertidal Zone of Sarangani Bay,
Southern Philippines
by
JOSE ANTONIO A. GUNTALIDAD, Ph. D.

• The only flowering plants that can
live underwater
• Related to terrestrial lilies and
gingers than to true grasses
• The main diet of dugongs and
green turtles
• Provide a habitat for many smaller
marine animals
• Absorb nutrients from coastal runoff
and stabilize sediment
• Unique among flowering plants
because they can live entirely
immersed in seawater.

• To determine the extent of seagrass beds in the four
intertidal zones of Sarangani Bay
• To describe the spatial variation of seagrass beds in
terms of the geological, physical and chemical
parameters
• To determine the biological characteristics of the
seagrasses in terms of density, frequency,
abundance, height of the 80% of the leaves and
canopy height
• To determine the different indicators of environmental
stress based on the gross morphology of seagrasses

Study Site

• Field and Laboratory Protocols were adopted from
the Global Seagrass Research Methods (Short and
Coles, 2001)
• Field and laboratory protocols were validated by two
seagrass experts from the City Environment and
Natural Resources Office (CENRO) of General
Santos City.
• Mapping was done at low tide when the seagrass
meadows were exposed.

• Bula in
General
Santos City
has
74,286.28m 2
• Tinoto in
Maasim has
17,820.00m 2
• Marine
Sanctuary in
Alabel
19,800.00
m 2 .
• Isla
Mellousa in
Glan has
20,072.50 m 2

• Two distinct
patterns
emerged
• Substrate in
Alabel and
General
Santos City
is
terrigenous.
• Glan and
Maasim is
marine in
origin
• Alabel and
General Santos
City are close to
Silway and
Buayan that
contribute to
the sediment
load
• Exposed corals
undergo
weathering and
erosion forming
the substrate of
the outer part of
the bay

• General Santos
• phosphate
• ammonia
• pH
• salinity
• Maasim
• phosphate
• pH
• ammonia
• salinity
• Alabel
• pH
• phosphate
• ammonia
• salinity
• Glan
• pH
• phosphate
• salinity
• ammonia

Enhalus acoroides (L.f.) Royle
Syringodium isoetifolium (Ascherson) Dandy

Halodule pinifolia (Miki) den Hartog
Halodule uninervis (Forsskål) Ascherson

Cymodocea serrulata (R. Brown) Ascherson
Cymodocea rotundata Ehrenberg and
Hemprich ex Ascherson;

Halophila ovalis (R. Brown) Hooker f.
Thalassia hemprichii (Ehrenberg) Ascherson

• Shortest height of
leaves and canopy was
observed in Glan while
the longest height was
observed in Alabel
• T. hemprichii has the
highest morphological
variation as it is found
in both terrigenous
and coralline substrate.

• Meadows in Glan, Maasim and General Santos
City served as docking sites for fishing vessels
• Those in General Santos City has the highest
levels of ammonia and the lowest pH
• Those in Maasim are exposed to strong waves
which favor larger species.

Thank you!