Marine Life Forms in the Bay of Loreto National Park
by Hector Trinidad
In the ocean there are myriad of life forms — algae and primitive bacteria, unicellular organisms, and multicellular organisms. Each of them shows adaptations that have enabled them to thrive in the marine environment to create specific niches for their survival. This survival depends largely on developing successful strategies to feed and reproduce, activities that take a lot of the energy that an organism produces.
Surviving species generally must be highly efficient and spend the least amount of energy possible on these activities. Even in a small area, one can observe a wide variety of adaptations and strategies that marine animals use to feed and reproduce.
Sponges: are they plants or animals?
This is a question that was answered by a Scottish biologist in 1825. In advance it is necessary to know that sponges live attached to the bottom of the ocean floor, in other words, they are immobile, although studies show that some may be developing an incipient mobility. Let’s see if we can answer the question with the support of the following information:
Sponges have different types of cells with specific functions:
- Porocytes, sponge’s body is covered with small pores, and it is through these pores that water and food is channeled to the interior of the sponge. Like all animals, a sponge has many different kinds of cells.
- Myocytes or contractile cells, which precisely contract to open or close the water inlet.
- Epithelial cells, which make up the surface of the sponge itself.
- Coanocitos, which are responsible for creating internal currents in the body of the sponges using tiny flagella, introducing food and oxygen, and expelling waste. The coanocitos can produce sperm, in the case of sexual reproduction.
- Arqueocitos, which are responsible for the movement and transport of nutrients.
- Esclerocitos, which secrete the structures that make up the skeleton, the spicules.
It is known that all these cells work together and communicate with each other.
A sponge’s body is held together by collagen, a protein that is found in animals. Another feature of similar to the animals is that they exhibit a reaction to a stimuli called behavior — sponges clearly exhibit behaviors in reaction to their environment.
Sponges are filter feeders, straining off bacteria and fine detritus from the water (unlike plants, which produce their own food through photosynthesis). Sponges absorb O2 and dissolved organic matter, and waste materials are carried away. From these and other factors, scientists conclude that sponges do belong in the animal kingdom, although they are considered very primitive animals. (Burnett, N. & Matsen, B. 2002)
The function of sponges in the marine environment.
Sponges act as water circulation pumps. A sponge can filter an amount of water equal to its volume within eight seconds, or viewed from another perspective, a sponge the size of a finger can move up to 22 liters (6 gallons) of water a day. Can you imagine the importance of sponges as water pumps?
Sponges are involved in symbiotic associations, in other words, biological interactions between two species that benefits at least one of them. It has been observed that sponges have blue-green algae on the outside, where light hits them and the alga engage in photosynthesis. Sponges take advantage of the excess of photosynthetic products and in return provide protection to the algae.
Are there sponges in the Bay of Loreto National Park?
Yes, according to the Park’s current management plan,there are 13 species of sponges in the Park.
SPECIES
Adocia gellindra
Aplysina fistularis
Aplysina gerardogreeni
Craniella arbacia
Epipolasis oxyspicula
Geodia mesotriaena
Halme hancocki
Leucetta losangelensis
Myxilla mexicensis
Oxeostilon burtoni
Sigmadocia edaphus
Tedania nigrescens
Terpios zeteki
In conclusion:
Sponges are a fundamental and ecologically strategic component in the marine environment. We recommend that all Park visitors avoid disturbing their habitat or removing them, and certainly avoid buying them, to discourage their removal.
References:
Burnett, N. & Matsen, B. 2002. The Shape of Life. Monterey Bay Aquarium Press. 123 p. http://www.asturnatura.com/articulos/porifera/ecologia.php
Originally published in Loreto.com
