Pacific Turtlegrass (Thalassia hemprichii): Complete Guide

Pacific Turtlegrass Featured Image

Pacific Turtlegrass is a type of seagrass with the scientific name Thalassia hemprichii. It’s found in the Indian Ocean, the Red Sea, and the western Pacific Ocean.

It’s known for its ability to grow faster with more CO2 in the water and tolerate lower light conditions caused by algal blooms.

This makes it able to respond positively to ocean acidification and other disturbances.

Where Is Pacific Turtlegrass Found?

Pacific Turtlegrass is mainly found in the following areas:

  • Labrador: It’s abundant here and has a large patch.
  • Chek Jawa: It’s found in small patches. A transact survey suggests it’s mainly found in the center of the seagrass lagoon.
  • Southern Islands: Scattered patches of this seagrass are found here.

What Are the Features of Pacific Turtlegrass?

Pacific Turtlegrass has the following features:

  • Leaves: Strap or curved, sickle-shaped leaves that are 0.5 to 1cm wide and 7 to 40cm long, usually less than 25 cm. The tips are rounded and smooth. The leaves may appear speckled with tannin cells that are red, purple, or dark brown. In Singapore, they often have cross-hatching on the long veins.
  • Rhizomes: Thick underground stems that are 2 to 4mm in diameter, white or pink. They have air channels and triangular node scars with persistent leaf sheaths.
  • Shoots: Emerge from the rhizomes; each shoot has 2 to 6 leaves encased in sheaths that are 3 to 8 cm long.

Pacific Turtlegrass is sometimes confused with other ribbon-like seagrasses. To tell them apart, look at the features of the leaves, rhizomes, and shoots.

How Does Pacific Turtlegrass Reproduce?

Pacific Turtlegrass has separate male and female plants. The flowers form at the base of the shoot and are hidden by the sheath until they emerge.

Male flowers are held on a long stalk and mature into 6 or more parts, while female flowers have a finer texture. Fruits are oval and prickly, containing up to 9 tiny seeds.

This seagrass flowers less frequently than other seagrasses and produces larger fruits.

What Role Does Pacific Turtlegrass Play in Its Habitat?

Algae often grow thickly on the leaves of Pacific Turtlegrass, turning them white or pink. Small grazing creatures, like snails, eat the algae.

Larger animals like dugongs and green turtles also eat this seagrass, which is why it’s sometimes called Dugong Grass or Turtle Grass.

What Is the Status of Pacific Turtlegrass and Its Threats?

Pacific Turtlegrass is listed as ‘Critically Endangered’ on the Red List of threatened plants of Singapore. This means that it’s at a high risk of becoming extinct in the wild.

You can check out what this plant looks like over here.

Scientific Classification

Kingdom:Plantae
Order:Alismatales
Family:Hydrocharitaceae
Genus:Thalassia
Scientific Name:Thalassia hemprichii
Also Known As:Pacific Turtlegrass

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