Procambarus clarkii a.k.a Red Swamp Crawfish

Procambarus clarkii is a freshwater crayfish species, native to the Southeastern United States, but found also on other continents, where it is often an invasive pest. It is known variously as the red swamp crawfish, red swamp crayfish, Louisiana crawfish or Louisiana crayfish.

Range and range expansion

The native range of P. clarkii is along the Gulf Coast from northern Mexico to the Florida panhandle, as well as inland, to southern Illinois and Ohio. It has also been introduced, sometimes deliberately, outside its natural range to countries in Asia, Africa, Europe and elsewhere in the Americas.

Ecology

P. clarkii is most commonly found in warm fresh water, such as slowly-flowing rivers, marshes, reservoirs, irrigation systems and rice paddies. It is considered to be the most ecologically plastic species in the Order Decapoda, and is able to grow quickly even in only seasonally present water, being able to tolerate dry spells of up to four months. P. clarkii grows quickly, and is capable of reaching weights in excess of 50 g, and sizes of 5½–12 cm long. It is also able to tolerate slightly saline water, which is unusual for a crayfish. The average lifetime of Procambarus clarkii is 5 years. It is known that some individuals have reached ages (in nature) over 6 years.

to be continued..

picture: here

Latest about Global Warming!

I was just surfing on the net and I stumbled on something about global warming and then I wanted to collect some "latest" global warming news for here. I want to share them with you;

-Species extinction still rising, experts warn>>

This story tells us about some species which have been added to a global database of threatened species. From the lowland gorillas of Africa to corals of the Galapagos Islands, more than 16,300 species are threatened with extinction, the group said in releasing its annual Red List.

For the first time, corals were added to the list due to threats that include the warm-water Pacific Ocean pattern El Nino and global warming. "The fact that corals are now present on the IUCN's Red List should sound warning bells to the world that the oceans are in trouble," said Simon Cripps, director of the global marine program at the World Wildlife Fund, an IUCN partner.

- 5 Deadliest Effect of Global Warming>>

In this story some dangerous effects of global warming was told us by numbers. If we look at that we can put in order the headlines like,

1.Polar ice caps melting
2.Economic consequences
3.Increased probability and intensity of droughts and heat waves
4.Warmer waters and more hurricanes
5.Spread of disease

And our last article about global warming is;

- Experts contest CO2 emmisions report>>

According to this story, officials and experts have contested a recent report that said China had for the first time overtaken the United States as the world's top producer of carbon dioxide (CO2).

The report, released on Tuesday by the Netherlands Environmental Assessment Agency, said China overtook the US in emissions of CO2 by 8 percent in 2006. While China was 2 percent below the US in 2005, coal consumption and increased cement production had caused the numbers to rise rapidly.

The details are in the original stories that we link.

It seems scary but so cute actually: Crawfish

I said before I'll introduce you to some animals or plants from sea or freshwaters. This post's subject is about crawfish (or crayfish).

Crayfish, often referred to as crawfish or crawdad, are freshwater crustaceans resembling small lobsters, to which they are closely related. They breathe through gills and are found in bodies of fresh water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is fresh water running, and which have shelter against predators. Most crayfish cannot tolerate polluted water, although some species such as the invasive Procambarus clarkii are more hardy. Some crayfish have been found living as much as 3 m(10 feet) underground.

Color and size varies with species, diet, and age. Most are red, some are green, brown, tan, or blue with black or orange markings in various combinations. Often juveniles will be a light tan color that turns to a deep red as an adult. The coloration depends in part on their diet, and can change with a change in diet. Adult size is 2" to 6" for most US species. Some Australian varieties can be much larger.

Crayfish also need to moult as they grow because their hard exoskeletons do not allow much room for expansion. Baby crayfish can moult on a daily basis but as they grow older, the regularity of moults decreases to a period of weeks or even months. The first few days after a moult, a crayfish's skin is very soft and it is very vulnerable to attacks from other animals and crayfish. The early signs of moulting include lack of appetite and a slow down in activity. During this period the crayfish ingests calcium into an internal organ, not into the exoskeleton.

When the crayfish is ready to moult, it will try to find a hiding spot. Then it will move onto its back and begin fanning its pincers, legs and swimmerets (under the tail) in order to get as much oxygen as possible. The carapace will begin to crack behind the head; the new appendages then pierce the old shell; and then after about five minutes, a sudden, violent movement will detach the old shell from the crayfish.

In the next post I'll tell everything that I know about Procambarus clarkii

resources: wikipedia and anapsid.org

pic1 (top-right): fws.gov, pic 2 (top-left): photos.dusac.org

Water in the world!

1386 milyon km3 of all water in the world is salt. In other words 96% and above is salt. Left behind 4% is freshwater resources and about 70% of these freshwaters are ice. The other 30% of freshwaters are underground waters. Surface freshwater resources like rivers, lakes compose 1% and below of all water of the world. In other words the freshwater in the world is very limited.

Unfortunately water consumption increased much more in the past 50 years, although there are limited water resources in the world. While total water consumption was 1000km3 in 1940, this amount of consumption was doubled in 1960 and in 1990 it reached 4130 km3.

If we put the countries in order according to water havings; we accept the countries which has average useable water for a person in a year below 1000m3 are “water poor”, which has average useable water for a person in a year below 2000m3 are “water fewness”, which has average useable water for a person in a year above 8000-10 000m3 are “water rich”.

Water consumption for a person in the world is about 8000 m3 in a year. 1,4 billion of people in the world can’t drink enough water. 2,3 billion of people are missing the healty water. According to some guesses, 3 billion and above people in the world will be faced with water famine in 2025 and following years. Additionally, the countries that will be in water distress's number will be 54 in 2050.

resource: picture 1(top-rgiht): www.iyonizesu.com, pic 2(bottom-left): www.aski.gov.tr and here

Let's learn something about Poriferans

I’ll tell about species also in aquasciences. First of all we’ll look over poriferans. Poriferans are commonly reffered to as sponges. They are animals of the phylum Porifera. They are primitive, sessile mostlymarine, water dwelling, filter feeders that pump water through their bodies to filter out particles of food matter.

Phylum Porifera is huge phylum that contains about 2500 species which lives in seas, lakes and rivers. Poriferans’ first examples ara belong to 600 million before present day. They’re the most primitive of multi pore animals and they have not improved tissue system. Sponges were being accepted as a plant untill 1830 by the researchers. At the end of the careful studies in following years, they were included in Kingdom Animalia. Poriferans have not an organ and a true tissue.

Choanocytes (also known as "collar cells") function as the sponge's digestive system and are remarkably similar to the protistan choanoflagellates.The collars are composed of microvilli and are used to filter particles out of the water. The beating of the choanocytes’ flagella creates the sponge’s water current.

Sponges have three body types: asconoid, syconoid and leuconoid;

Asconoid sponges are tubular with a central shaft called the spongocoel.The beating of choanocyte flagella forces water into the spongocoel through pores in the body wall. Choanocytes line the spongocoel and filter nutrients out of the water.

Syconoid sponges are similar to asconoids. They have a tubular body with a single osculum, but the body wall is thicker and more complex than that of asconoids and contains choanocyte-lined radial canals that empty into the spongocoel. Water enters through a large number of dermal ostia into incurrent canals and then filters through tiny openings called prosopyles into the radial canals. There food is ingested by the choanocytes. Syconoids do not usually form highly branched colonies as asconoids do. During their development, syconoid sponges pass through an asconoid stage.

Leuconoid sponges lack a spongocoel and instead have flagellated chambers, containing choanocytes, which are led to and out of via canals.

A sponge’s form can change as per conditions that it lives in. They accommodate to the ambient.

They can reproduce sexual and also asexual. They have not a special reproduction organ. Sexual reproduce is made by sex pores. Asexual reproduction is made by gemmation.

Sponges have no true circulatory system; however the water current is used for circulation. Dissolved gases are brought to cells and enter the cells via simple diffusion. Metabolic wastes are also transferred to the water through diffusion. Sponges pump remarkable amounts of water.

An example for Phylum Porifera:

Verongia aerophoba (Schmidt)

Famillia: Verongiidae

Eng: Tube sponge

Color: Their color is bright yellow.

Where they found: The reefs are their main living place. They can be seen near algae. Usually can be seen shallow waters. They’re appeared in Mediterranean and Agean Sea.

Characteristics: Their bodiesare as a column and their height is about 20 cm. The pores perform their staminal actions. Aerophoba means “don’t like air”. When they are injured or coming out of water, their colors turn into brown or black.

Nutrients: Their nutrients are plankton in the water, very small organisms and organic materials.

Pictures:

Resources: here, here and Derin Mavi Atlas (Deep Blue Atlas)

Pic1 (top-right): members.fotunecity.com

Pic2 (top-left): users.tamuk.edu

Pic3 (bottom-left): www.asturnatura.com

Pic4 (bottom-center): www.drm-drustvo.si

Pic5 (bottom-right): www.taucher.net