Intertidal zones are coastal areas that are exposed during low tide and submerged during high tide, featuring various layers: splash and spray zone, high-tide zone, mid-tide zone, and low-tide zone. Each layer supports different organisms adapted to their unique environment, with specific characteristics necessary for survival amidst changing conditions. Below the intertidal zones lies the subtidal zone, which remains underwater and provides a more stable habitat for marine life, such as seals and sea otters.

1. INTERTIDAL
ZONES

2. INTERTIDAL ZONES
•INTERTIDAL ZONES MAKE UP THE COASTS.
THESE ARE WHERE THE SANDY BEACHES MEET
THE SEA DURING HIGH TIDE AND LOW TIDE.
THE AREA OF INTERTIDAL ZONE APPEARS
DURING LOW TIDE AND HIDES UNDERWATER
DURING HIGH TIDE.

3. HIGH TIDES LOW TIDES

4. •SINCE THE PHILIPPINES IS SURROUNDED BY
DIFFERENT SEAS AND OCEANS, IT IS
SURROUNDED BY INTERTIDAL ZONES AS
WELL. THE INTERTIDAL ZONES ARE DIVIDED
INTO DIFFERENT LAYERS: THE SPLASH AND
SPRAY ZONE, HIGH-TIDE ZONE, MID-TIDE
ZONE, AND LOW-TIDE ZONE.

6. • TONE SALES AND SPRAY ZONE HAS LIMITED VEGETATION. IT IS
WHERE THE BIG ROCKS ARE FOUND. HENCE, THERE ARE MANY
LIMPETS IN THIS LAYER. THESE ORGANISMS ATTACH THEMSELVES TO
ROCKS OR OTHER HARD GROUNDS.

7. • IN HIGH-TIDE ZONE, SOME VEGETATION OCCURS. THIS AREA
IS COVERED WITH WATER DURING HIGH TIDES ONLY. IT IS A
VERY HIGH SALINE ENVIRONMENT. COMMON ORGANISMS
FOUND IN THIS AREA ARE ANEMONES, BARNACLES, AND
BRITTLE STARS.

9. • THE MID-TIDE ZONE RECEIVES LESS SUNLIGHT COMPARED
TO THE HIGH-TIDE ZONE. THEREFORE, ITS SALINITY LEVEL IS
NOT THAT HIGH COMPARED TO THE HIGH-TIDE ZONE.
SINCE THE TEMPERATURE AND THE SALINITY LEVEL ARE
MORE STABLE IN THIS ZONE, THERE IS A HIGHER
POPULATION OF MARINE VEGETATION COMPARED TO THE
HIGH-TIDE ZONE. EXAMPLES OF ORGANISMS COMMONLY
FOUND IN THIS AREA ARE WINKLED WHELKS, BATILLARIA
SNAILS, AND JAPANESE.

11. • IN LOW-TIDE ZONE, LARGE ORGANISMS ARE FOUND. THIS
AREA IS USUALLY SUBMERGED IN WATER, UNLESS THERE IS
AN EXTREMELY LOW TIDE. MOST OF THE MARINE
VEGETATION OCCURS IN THIS AREA. THE ORGANISMS IN
THIS AREA CANNOT SURVIVE DRYNESS AND RAPID
CHANGE IN TEMPERATURE AND SALINITY LEVELS.
EXAMPLES OF ORGANISMS FOUND IN THIS AREA ARE SEA
SLUGS, CHITONS, AND SEA CUCUMBERS.

13. • ORGANISMS IN THE INTERTIDAL ZONES MUST HAVE CERTAIN CHARACTERISTICS TO SURVIVE
THEIR CHALLENGING ENVIRONMENT. DURING LOW TIDE, THEY MUST SURVIVE EXPOSURE TO
AIR.
• THEY MUST ALSO ADAPT TO THE CHANGES IN THE SALINITY OF WATER AND IMPACT OF
WAVES.
• THEY NEED TO PROTECT THEMSELVES FROM MARINE AND TERRESTRIAL PREDATORS. THERE ARE
ALSO OTHER ORGANISMS THAT CAN BE FOUND IN THE SUBTIDAL ZONE, WHICH IS THE AREA
UNDERNEATH THE INTERTIDAL ZONE. THIS AREA IS CONTINUOUSLY COVERED BY WATER
WHETHER IT IS LOW TIDE OR HIGH TIDE. THE TEMPERATURE, WATER PRESSURE, AND SUNLIGHT
RADIATION IN THIS ZONE REMAIN CONSTANT, WHICH MAKES IT MORE STABLE THAN THE
INTERTIDAL ZONE.
• EXAMPLES OF ORGANISMS FOUND IN THE SUBTIDAL ZONE ARE SEALS, SEA OTTERS, AND
MANY DIVING BIRDS.