海洋的生命之歌
As the first ocean appeared on the earth, and as the first life born in the ocean, the interaction between organism and inorganism continued untill now. In order to live in the three-dimensional space in the blue ocean, marine organisms evolved special physiologic mechanism and unique way of life to adapt to the hash environment very different from the land.

Organisms need to overcome environmental conditions of salinity and temperature to live in the ocean. The salinity of the sea water is usually higher than inside of the orgnisms, in other words, the ionic concentration is much higher. To maintain the balance of osmosis, water inside the organisms permeates into sea water through skin and causes ionic concentration in the body to increase. The increasing ion concentration resulted in elevation of salinity. Enzyme activity or organic molecules will be inhibited by this abnormal condition and hence the normal physiologic functions.

Marine orgnisms have to balance ionic concentration between their body and the surrounding to keep physiologic function working properly. For example, in order to compensate the water loss from the body, fishes will take large amount of seawater, reduce urine output and excrete excess salt from gills or intestines. Even sea turtle has a gland in their eyes to excrete excess salt, misleading people to believe that sea turtle can also cry as human beings do.

Another important environmental factor, temperature, will change metabolic rate in orginisms. Most of the time, ocean temperature is very stable, but sometimes changes in different region of the earth. At high temperature condition, metabolic rate of organism will increase, and decrease at lower temperature vice versa.

Body heat of creatures will lost in seawater constantly, some creatures will raise body heat by muscle contraction such as tuna or shark. We call this kind of creatures endotherms, or heat from inner. Others cannot produce enough heat and emit their heat into surroundings. This makes their body temperature the same as surroundings. We call them poikilothermal or temperature changing animals.

Marine creatures, from the smallest protozoa to the biggest animals, regardless of their body size, they always have to adapt to the ocean. For protozoa, the ratio of surface area to volume is greater, which means they can perform diffusion or osmotic activity consuming less energy to adjust their salinity and temperature.

For larger animals, their ratio of surface area to volume is smaller. That means they have to use more energy to overcome salinity and temperature variation by developing complicated metabolic mechanism.

The changing environment of the ocean gives birth to a diversity of orginisms, and different orginisms will change the ocean environment indirectly by different biologic characteristics. Ocean is like a giant organism. With the interaction of organic and inorganic elements, the journey of living creatures continues, generation by generation.

大海中的小巨人
There is a kind of orginism that you cannot see with the naked eyes but certainly is related to the biospheric circulation.

They can survive not only under hot broil lava, but also in freezing, high pressure abyss of sea. They are the oldest life-form ever appearing on earth. Their simplicity in structure makes scientists pondering the mystery of life until today. They are the microorganisms.

Marine microorganisms are not only the origin of evolution but also an important food supply for marine creatures supporting the food chain in the ocean.

Marine microorganisms consist of all kinds of tiny life like some prokaryotes: archaea, algae, and protists. Microorganisms play an important role of decomposing organic materials and cycling nutrients. Some other microorganisms such as cyanobacteria also produce and provide energy for other creatures by photosynthesis or nitrogen fixation.

The most amazing thing is some marine microorganisms survive in the deep ocean that sunlight cannot reach. Without sunlight, microorganism cannot perform photosynthesis to manufacture energy for living, but some microorganisms use hydrogen sulfide in hydrothermal vents under ocean, such as the one near Gueishan Island in Taiwan, to produce energy.

Marine microorganisms are small but very important for the biosphere from the forming of ocean billion years ago until now. Don’t forget the little giants in the big blue sea when you are staring at the fascinating sea water. The microorganisms.

海中的游泳高手-魚類
Have you ever kicking your leg swimming hard to catch up a group of fish but found yourself so clumsy in the ocean? Fishes are the earliest vertebrates born on the earth in Ordovician about five hundred million years ago, and are also the vertebrates in largest quantity now. Fishes now can be classified into three classes: Agnatha, Chondrichthyes, and Osteichthyes. Agnatha is the most ancient kind of fish which lack maxilla and mandibles. Bones of Chondrichthyes is constructed by cartilages.

The biggest fish is whale shark (Rhincodon typus). Their body length can grow up to 18 meters. Having a giant body shape, whale shark has a tender heart. They move tardily and feed by filtering. Now whale shark is a threatened species due to excessive fishing and is protected by the ISPA (International Society for the Protection of Animals).

The marine area around Taiwan varies from shallow coral reef coast to deep sea down to thousands meters in depth. Owing to the diversity of geology, there are various kinds and large amount of fishes. The Research Center for Biodiversity in Academia Sinica is building a database for research and educational purposes.