Microbiology/Genetics

Grass that Eats Cows

The mixotrophy

By Stefan Anitei, Science Editor

25th of June 2007, 06:57 GMT

Adjust text size:

We all know that cows eat grass. But what if grass ate the cows? Surprisingly, there are some situations of this kind in nature.
In terrestrial ecosystems, plants are the only ones that can produce their own food starting from minerals (carbon dioxide from the air, nitrogen and phosphorus from the ground) and water by using chlorophyll and other pigments which can capture the sunlight energy. This means the plants are the producers and

form the base of the food chain.

Still, there are plants that can act as both "plants" and as "animals" at the same time. These organisms are mixotrophs and this type of feeding is known as mixotrophy ("mixed nutrition"). This dual nutritional behavior changes the relations in the food chain.

One classic example are the carnivorous plants, but these plants do not eat animals for feeding, they just get their nitrogen this way. Instead, there are algae that can fully function as either "plants", producing their own food as "animals" also, eating other plants or even their own grazers.

Wanderson Carvalho from the University of Kalmar in Sweden has investigated the behavior of these organisms and what might be the effects of this nutrition on the environment, economy and public health issues.

Until recently it was thought that the land system worked also for lakes and the sea, with phytoplankton (microalgae) being the producers and serving as food for zooplankton (microscopic animals), food for small fishes, eaten by bigger fishes and then by humans and other top predators.

Wanderson Carvalho had classified into two mixotrophic species how much nitrogen and phosphorous they require when they act as "plants" and as "animals", respectively. When there is a shortage of these two nutrients, mixotrophs can outcompete other algae species by consuming them and this helps them cope with the little available nutrients found in the water. The "animal" nutrition also can provide food for the mixotrophs when light is low or lacking.

When they have nothing to prey upon, mixotrophs employ their own photosynthetic apparatus to survive until suitable prey is available again. The mixotrophy can also decrease competition since the mixotrops eat their competitors and their predators alike. Because of their double ability, mixotrophs have higher chances of surviving adverse periods and to form blooms, turning potentially harmful to the environment.

TAGS:

algae | plant animal

SEARCH THE NEWS ARCHIVE :

Today's News | Yesterday's News | News Archive

User opinions:

No user comments yet.

Be the first to express your opinion using the form below!

Share your opinion:

SUBMIT PROGRAM \| ADVERTISE \| GET HELP \| SEND US FEEDBACK \| RSS FEEDS \| ENTER NEWS SITE \| ENGLISH BOARD \| ROMANIAN FORUM
© 2001 - 2008 Softpedia. All rights reserved. Softpedia™ and the Softpedia™ logo are registered trademarks of SoftNews NET SRL.	Copyright Information \| Privacy Policy \| Terms of Use \| Update your software \| Archive

NEWS CATEGORIES: