Desertification

2019-05-05T20:08:14Z

Cengel:

== '''Overview''' ==

----

Desertification is a natural or human induced process in which fertile land becomes irreversibly desert. The resulting loss of plant life leads to a decrease in overall bio productivity.[1] Barren soil becomes more susceptible to erosion and more vulnerable to evaporation and higher temperatures. The cause of this process is most often attributed to anthropogenic climate change, but a multitude of factors influence desertification. [2] Rapid desertification is expected to have drastic environmental, economic and political consequences. [[File:desertification map.PNG|thumb|alt=map|Figure 1. Human Induced Desertification[6]]]

== '''Causes''' ==

----

Desertification is most attributable to human activity and climate change. According to scientists, poorly managed livestock herds has led to overgrazing of grasslands. In addition, the expansion of agriculture and deforestation have decreased overall natural vegetation. In turn, loss of vegetation has led to a host of problems resulting in the degradation of land. The change from fully grassed lands to scattered shrubbery leaves land bare and susceptible to erosion. Unprotected soil surfaces are also prone to salinization by evaporation and water logging. [3] Nutrients are washed away, fauna dies from lack of nutrients or washes away as well.
Scientists have identified several driving forces behind desertification. It is contended that a combination of multiple factors are at play. [2]
Leading causes include:
*Agricultural activities [[File:Desertification causes.PNG|thumb|alt=causes.|Figure 2: Leading causes of desertification [2]]]''.
*Infrastructure extension
*Wood extraction and related activities
*Increased aridity
*Demographic factors
*Economic factors
*Technological factors
*Climatic factors
*Policy and institutional factors
*Cultural factors

== '''Effects''' ==

----
Desertification is expected to affect irrigated croplands negatively. Of the over 2 million square kilometers of irrigated croplands, more than 60% is located in drylands, with 30% of this land considered severely degraded. [1] Biological productivity of degraded land will drop significantly due to accumulation of salts in this soil. Without water to wash away accumulated salts they will remain in the soil, transforming the soil’s quality as farmland. Rangelands are also susceptible to degradation via desertification. Grazing animals often leave land barren of vegetation, exposing soil to wind and erosion. Preferential grazing may also alter plant communities. [3]

== '''Prevention and Reversal''' ==

----

There are many techniques for the prevention and reversal of desertification. Many of these methods rely heavily on the availability and usage of water. Some look to reforestation as a means of re-greening deserts. Studies have indicated that extended wet periods can reverse historical environmental regimes. [4]

A long-term study in the Qubqi Desert (Inner Mongolia) has tested the artificial inoculation of soil with cyanobacteria to stimulate plant growth. Cyanobacteria are known to stabilize soils by enriching available nutrients and increasing moisture content. Results from the study indicate that through the use of cyanobacteria almost all native plant species can be regrown in an area that has undergone desertification. [7]

One of the most controversial proposals comes from Allan Savory, founder of the Savory Institute. Savory proposes a holistic approach to reversing desertification, relying on, not avoiding, livestock to re-green. Savory theorizes that through proper management, agriculture can be employed in a way to mimic nature and farmers can use sustainable farming to prevent further degradation.[5]

== '''References''' ==

----

[1] Rafferty, J. P., and S. L. Pimm. 2019, March 22. Desertification. Encyclopædia Britannica, inc. https://www.britannica.com/science/desertification.

[2] Geist, H. J., and E. F. Lambin. 2004. Dynamic Causal Patterns of Desertification. BioScience 54:817.

[3] Huang, J., H. Yu, X. Guan, G. Wang, and R. Guo. 2015. Accelerated dryland expansion under climate change. Nature Climate Change 6:166–171.

[4] Peters, D. P. C., J. Yao, O. E. Sala, and J. P. Anderson. 2011. Directional climate change and potential reversal of desertification in arid and semiarid ecosystems. Global Change Biology 18:151–163.

[5] Holistic Management. https://www.savory.global/holistic-management/.

[6] Natural Resources Conservation Service. (n.d.). . https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/worldsoils/?cid=nrcs142p2_054004.

[7] Lan, S. et al. 2014. Artificially Accelerating the Reversal of Desertification: Cyanobacterial Inoculation Facilitates the Succession of Vegetation Communities. Environmental Science & Technology 2014 48 (1), 307-315.

Desertification

2019-05-05T20:05:16Z

Cengel:

== '''Overview''' ==

----

Desertification is a natural or human induced process in which fertile land becomes irreversibly desert. The resulting loss of plant life leads to a decrease in overall bio productivity.[1] Barren soil becomes more susceptible to erosion and more vulnerable to evaporation and higher temperatures. The cause of this process is most often attributed to anthropogenic climate change, but a multitude of factors influence desertification. [2] Rapid desertification is expected to have drastic environmental, economic and political consequences. [[File:desertification map.PNG|thumb|alt=map|Figure 1. Human Induced Desertification[6]]]

== '''Causes''' ==

----

Desertification is most attributable to human activity and climate change. According to scientists, poorly managed livestock herds has led to overgrazing of grasslands. In addition, the expansion of agriculture and deforestation have decreased overall natural vegetation. In turn, loss of vegetation has led to a host of problems resulting in the degradation of land. The change from fully grassed lands to scattered shrubbery leaves land bare and susceptible to erosion. Unprotected soil surfaces are also prone to salinization by evaporation and water logging. [3] Nutrients are washed away, fauna dies from lack of nutrients or washes away as well.
Scientists have identified several driving forces behind desertification. It is contended that a combination of multiple factors are at play. [2]
Leading causes include:
*Agricultural activities [[File:Desertification causes.PNG|thumb|alt=causes.|Figure 2: Leading causes of desertification [2]]]''.
*Infrastructure extension
*Wood extraction and related activities
*Increased aridity
*Demographic factors
*Economic factors
*Technological factors
*Climatic factors
*Policy and institutional factors
*Cultural factors

== '''Effects''' ==

----
Desertification is expected to affect irrigated croplands negatively. Of the over 2 million square kilometers of irrigated croplands, more than 60% is located in drylands, with 30% of this land considered severely degraded. [1] Biological productivity of degraded land will drop significantly due to accumulation of salts in this soil. Without water to wash away accumulated salts they will remain in the soil, transforming the soil’s quality as farmland. Rangelands are also susceptible to degradation via desertification. Grazing animals often leave land barren of vegetation, exposing soil to wind and erosion. Preferential grazing may also alter plant communities. [3]

== '''Prevention and Reversal''' ==

----

There are many techniques for the prevention and reversal of desertification. Many of these methods rely heavily on the availability and usage of water. Some look to reforestation as a means of re-greening deserts. Studies have indicated that extended wet periods can reverse historical environmental regimes. [4]

A long-term study in the Qubqi Desert (Inner Mongolia) has tested the artificial inoculation of soil with cyanobacteria to stimulate plant growth. Results from the study, with almost all of the original plant species regrowing, show promising results for this method of reversal. [7]

One of the most controversial proposals comes from Allan Savory, founder of the Savory Institute. Savory proposes a holistic approach to reversing desertification, relying on, not avoiding, livestock to re-green. Savory theorizes that through proper management, agriculture can be employed in a way to mimic nature and farmers can use sustainable farming to prevent further degradation.[5]

== '''References''' ==

----

[1] Rafferty, J. P., and S. L. Pimm. 2019, March 22. Desertification. Encyclopædia Britannica, inc. https://www.britannica.com/science/desertification.

[2] Geist, H. J., and E. F. Lambin. 2004. Dynamic Causal Patterns of Desertification. BioScience 54:817.

[3] Huang, J., H. Yu, X. Guan, G. Wang, and R. Guo. 2015. Accelerated dryland expansion under climate change. Nature Climate Change 6:166–171.

[4] Peters, D. P. C., J. Yao, O. E. Sala, and J. P. Anderson. 2011. Directional climate change and potential reversal of desertification in arid and semiarid ecosystems. Global Change Biology 18:151–163.

[5] Holistic Management. https://www.savory.global/holistic-management/.

[6] Natural Resources Conservation Service. (n.d.). . https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/use/worldsoils/?cid=nrcs142p2_054004.

[7] Lan, S. et al. 2014. Artificially Accelerating the Reversal of Desertification: Cyanobacterial Inoculation Facilitates the Succession of Vegetation Communities. Environmental Science & Technology 2014 48 (1), 307-315.

Protozoa

2019-05-05T01:46:26Z

Cengel:

== '''Description:''' ==

[[File:Protistdiversity.png|thumb|Protozoa diversity [8]]]Protozoans, an informal subfamily of protists, are single-celled animal-like eukaryote. This subgrouping of protists is highly paraphyletic and the organisms characterized as such do not necessarily share a common ancestor.[1] Protozoans occupy a variety of environments, ranging from the South to the North Pole. They can be free-living, or form parasitic or symbiotic relationships with hosts. Protozoans are motile, heterotrophic organisms that exhibit animal like behaviors, such as predation. Body sizes range from 5 to 500 µm.

==='''Life Cycle/Reproduction:'''===
Protozoa are known to reproduce both asexually and sexually. Sexual reproduction is more rare among protozoa and asexual reproduction is more common. Asexual reproduction in protozoa includes binary fission, budding and spores. Among the sexual reproducers, amoeba are known to engage in process known as conjugation. This process involves the fusion of oral groves and the exchange of genetic data.

==='''Locomotion:'''===
Protozoa are motile organisms. They generally move by one of three different mechanisms; amoeboid action, ciliary action or flagella. Amoebic action involves the use of pseudopods, or false feet. The pseudopods are used to move the body forward through extension, followed by a flow through. Ciliary action involves the beating of many hair-like extensions. A flagellum acts as a whip to propel a protozoa, either through pushing or pulling.[1]

== '''In Soil''': ==

[[File:Protozoan picture.PNG|thumb|Main Types of Soil Protozoan [8]]]Soil protozoans are comprised of four major groups: the [[flagellates]], [[naked amoeba]], [[testaceans]], and [[ciliates]]. Each group has a distinctive body design and are classified based on their shape. As soil inhabitants, protozoans play an important role in mineralization of nutrients and increasing nutrient supply. Through grazing activity, protozoans stimulate decomposition, resulting in nitrogen excretion. The nitrogen is then bioavailable for plant uptake. As heterotrophs, protozoans rely on eating other organisms for nutrition. Some protozoans consume entire organisms, while others take up their waste products. Their feeding habits make protozoans an important component of regulating bacterial populations. Although it is not entirely understood, bacterial feeding stimulates bacterial growth.[[File:protozoabacteria.jpg|200px|thumb|left|protozoa feeding on bacteria]]

== '''Methods for Extraction:''' ==

Past methods for extraction focused heavily on culturing populations, but due to failure of some species to be cultured in a lab, this method is more rapidly being replaced by modern techniques. With advancements in genetic techniques, eDNA can now be amplified for use as an identifying tool. eDNA coupled with next generation sequencing has greatly aided in identifying and quantifying soil organisms that was previously unattainable with previous techniques.

== '''As Parasites''' ==

Many protozoa are parasitic in nature, inflicting their hosts with disease. Four main groups of protozoa are known to cause disease to humans; the Sarcodina , Mastigophora, Ciliophora and, Sporozoa. Due to their rapid reproduction, small populations can cause serious damage to their hosts. Parasitic protozoa can be transmitted via the oral-fecal route or via an arthropod vector, such as mosquitoes.

== '''References''' ==

[1] 2016. About Parasites.in C. f. D. Control, https://www.cdc.gov/parasites/about.html

[2] Alphei, J. e. a. 1996. Protozoa, Nematoda and Lumbricidae in the Rhizosphere of Hordelymus europaeus
(Poaceae): Faunal Interactions, Response of Microorganisms and Effects on Plant Growth. Oecologia 106:111-126.

[3] Blackwell, W. P., M. 2001. The Protozoa, a Kingdom by Default? The American Biology Teacher 63:483-488+490.

[4] Diaz, J. M. L.-P., Johanna E.M. 2010. Protozoan.in E. Britannica, https://www.britannica.com/science/protozoan

[5] Geisen, S. e. a. 2018. Soil protists: a fertile frontier in soil biology research. FEMS Microbiology Reviews 42:293–323.

[6] Ingham, E. R. Soil Protozoa. USDA, https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053867

[7] Koller, R. e. a. 2013. Protozoa enhance foraging efficiency of arbuscular mycorrhizal fungi for mineral
nitrogen from organic matter in soil to the benefit of host plants. The New Phytologist 199:203-211.

[8] Sadava, D. e. a. 2011. Life: the science of biology. Sinauer Associates.

[9] Yamanouchi, K. e. a. 2019. Development of a method to extract protozoan DNA from black soil. Parasite Epidemiol Control.

Protozoa

2019-05-05T00:53:22Z

Cengel:

== '''Description:''' ==

[[File:Protistdiversity.png|thumb|Protozoa diversity [8]]]Protozoans, an informal subfamily of protists, are single-celled animal-like eukaryote. This subgrouping of protists is highly paraphyletic and the organisms characterized as such do not necessarily share a common ancestor.[1] Protozoans occupy a variety of environments, ranging from the South to the North Pole. They can be free-living, or form parasitic or symbiotic relationships with hosts. Protozoans are motile, heterotrophic organisms that exhibit animal like behaviors, such as predation. Body sizes range from 5 to 500 µm.

==='''Life Cycle/Reproduction:'''===
Protozoa are known to reproduce both asexually and sexually. Sexual reproduction is more rare among protozoa and asexual reproduction is more common. Asexual reproduction in protozoa includes binary fission, budding and spores. Among the sexual reproducers, amoeba are known to engage in process known as conjugation. This process involves the fusion of oral groves and the exchange of genetic data.

==='''Locomotion:'''===
Protozoa are motile organisms. They generally move by one of three different mechanisms; amoeboid action, ciliary action or flagella. Amoebic action involves the use of pseudopods, or false feet. The pseudopods are used to move the body forward through extension, followed by a flow through. Ciliary action involves the beating of many hair-like extensions. A flagellum acts as a whip to propel a protozoa, either through pushing or pulling.[1]

== '''In Soil''': ==

[[File:Protozoan picture.PNG|thumb|Main Types of Soil Protozoan [8]]]Soil protozoans are comprised of four major groups: the [[flagellates]], [[naked amoeba]], [[testaceans]], and [[ciliates]]. Each group has a distinctive body design and are classified based on their shape. As soil inhabitants, protozoans play an important role in mineralization of nutrients and increasing nutrient supply. Through grazing activity, protozoans stimulate decomposition, resulting in nitrogen excretion. The nitrogen is then bioavailable for plant uptake. As heterotrophs, protozoans rely on eating other organisms for nutrition. Some protozoans consume entire organisms, while others take up their waste products. Their feeding habits make protozoans an important component of regulating bacterial populations. Although it is not entirely understood, bacterial feeding stimulates bacterial growth.[[File:protozoabacteria.jpg|200px|thumb|left|protozoa feeding on bacteria]]

== '''Methods for Extraction:''' ==

Past methods for extraction focused heavily on culturing populations, but due to failure of some species to be cultured in a lab, this method is more rapidly being replaced by modern techniques. With advancements in genetic techniques, eDNA can now be amplified for use as an identifying tool. eDNA coupled with next generation sequencing has greatly aided in identifying and quantifying soil organisms that was previously unattainable with previous techniques.

== '''As Parasites''' ==

Many protozoa are parasitic in nature, inflicting their hosts with disease. Four main groups of protozoa are known to cause disease to humans; the Sarcodina , Mastigophora, Ciliophora and, Sporozoa. Due to their rapid reproduction, small populations can cause serious damage to their hosts. Parasitic protozoa can be transmitted via the oral-fecal route or via an arthropod vector, such as mosquitoes.

== '''References''' ==

2019-05-02T21:38:46Z

Cengel:

Protozoa

2019-05-02T21:31:15Z

Cengel:

== '''Description:''' ==

[[File:Protistdiversity.png|thumb|The Diversity of Protozoans [8]]]Protozoans, an informal subfamily of protists, are single-celled animal-like eukaryote. This subgrouping of protists is highly paraphyletic and the organisms characterized as such do not necessarily share a common ancestor. Protozoans occupy a variety of environments, ranging from the South to the North Pole. They can be free-living, or form parasitic or symbiotic relationships with hosts. Protozoans are motile, heterotrophic organisms that exhibit animal like behaviors, such as predation. Body sizes range from 5 to 500 µm.

'''Life Cycle/Reproduction:'''

Protozoa are known to reproduce both asexually and sexually. Sexual reproduction is more rare among protozoa and asexual reproduction is more common. Asexual reproduction in protozoa includes binary fission, budding and spores. Among the sexual reproducers, amoeba are known to engage in process known as conjugation. This process involves the fusion of oral groves and the exchange of genetic data.

'''Locomotion:'''

Protozoa are motile organisms. They generally move by one of three different mechanisms; amoeboid action, ciliary action or flagella. Amoebic action involves the use of pseudopods, or false feet. The pseudopods are used to move the body forward through extension, followed by a flow through. Ciliary action involves the beating of many hair-like extensions. A flagellum acts as a whip to propel a protozoa, either through pushing or pulling.

== '''In Soil''': ==

[[File:Protozoan picture.PNG|thumb|Main Types of Soil Protozoan [8]]]Soil protozoans are comprised of four major groups: the flagellates, naked amoeba, testaceans, and ciliates. Each group has a distinctive body design and are classified based on their shape. As soil inhabitants, protozoans play an important role in mineralization of nutrients and increasing nutrient supply. Through grazing activity, protozoans stimulate decomposition, resulting in nitrogen excretion. The nitrogen is then bioavailable for plant uptake. As heterotrophs, protozoans rely on eating other organisms for nutrition. Some protozoans consume entire organisms, while others take up their waste products. Their feeding habits make protozoans an important component of regulating bacterial populations. Although it is not entirely understood, bacterial feeding stimulates bacterial growth.

----

== '''Methods for Extraction:''' ==

Past methods for extraction focused heavily on culturing populations, but due to failure of some species to be cultured in a lab, this method is more rapidly being replaced by modern techniques. With advanced in genetic techniques, eDNA can now be amplified for use as an identifying tool. eDNA coupled with next generation sequencing has greatly aided in identifying and quantifying soil organisms that was previously unattainable with previous techniques.

Protozoa

2019-05-02T21:30:43Z

Cengel:

== '''Description:''' ==

[[File:Protistdiversity.png|thumb|The Diversity of Protozoans [8]]]Protozoans, an informal subfamily of protists, are single-celled animal-like eukaryote. This subgrouping of protists is highly paraphyletic and the organisms characterized as such do not necessarily share a common ancestor. Protozoans occupy a variety of environments, ranging from the South to the North Pole. They can be free-living, or form parasitic or symbiotic relationships with hosts. Protozoans are motile, heterotrophic organisms that exhibit animal like behaviors, such as predation. Body sizes range from 5 to 500 µm.

'''Life Cycle/Reproduction:'''

Protozoa are known to reproduce both asexually and sexually. Sexual reproduction is more rare among protozoa and asexual reproduction is more common. Asexual reproduction in protozoa includes binary fission, budding and spores. Among the sexual reproducers, amoeba are known to engage in process known as conjugation. This process involves the fusion of oral groves and the exchange of genetic data.
----

'''Locomotion:'''

Protozoa are motile organisms. They generally move by one of three different mechanisms; amoeboid action, ciliary action or flagella. Amoebic action involves the use of pseudopods, or false feet. The pseudopods are used to move the body forward through extension, followed by a flow through. Ciliary action involves the beating of many hair-like extensions. A flagellum acts as a whip to propel a protozoa, either through pushing or pulling.

== '''In Soil''': ==

[[File:Protozoan picture.PNG|thumb|Main Types of Soil Protozoan [8]]]Soil protozoans are comprised of four major groups: the flagellates, naked amoeba, testaceans, and ciliates. Each group has a distinctive body design and are classified based on their shape. As soil inhabitants, protozoans play an important role in mineralization of nutrients and increasing nutrient supply. Through grazing activity, protozoans stimulate decomposition, resulting in nitrogen excretion. The nitrogen is then bioavailable for plant uptake. As heterotrophs, protozoans rely on eating other organisms for nutrition. Some protozoans consume entire organisms, while others take up their waste products. Their feeding habits make protozoans an important component of regulating bacterial populations. Although it is not entirely understood, bacterial feeding stimulates bacterial growth.

----

== '''Methods for Extraction:''' ==

Past methods for extraction focused heavily on culturing populations, but due to failure of some species to be cultured in a lab, this method is more rapidly being replaced by modern techniques. With advanced in genetic techniques, eDNA can now be amplified for use as an identifying tool. eDNA coupled with next generation sequencing has greatly aided in identifying and quantifying soil organisms that was previously unattainable with previous techniques.

Protozoa

2019-05-02T20:03:11Z

Cengel:

Protozoa

2019-05-02T20:01:20Z

Cengel: Created page with " == '''Description:''' == The Diversity of Protozoans [8]Protozoans, an informal subfamily of protists, are single-celled animal-like euk..."

Protozoans

2019-05-02T19:52:35Z

Cengel:

Protozoans

2019-05-02T19:52:04Z

Cengel:

== '''Description:''' ==

[[File:protistdiversity.PNG|thumb|The Diversity of Protozoans [8]]]Protozoans, an informal subfamily of protists, are single-celled animal-like eukaryote. This subgrouping of protists is highly paraphyletic and the organisms characterized as such do not necessarily share a common ancestor. Protozoans occupy a variety of environments, ranging from the South to the North Pole. They can be free-living, or form parasitic or symbiotic relationships with hosts. Protozoans are motile, heterotrophic organisms that exhibit animal like behaviors, such as predation.

----

== '''In Soil''': ==

[[File:Protozoan picture.PNG|thumb|Main Types of Soil Protozoan [8]]]Soil protozoans are comprised of four major groups: the flagellates, naked amoeba, testaceans, and ciliates. Each group has a distinctive body design and are classified based on their shape. As soil inhabitants, protozoans play an important role in mineralization of nutrients and increasing nutrient supply. Through grazing activity, protozoans stimulate decomposition, resulting in nitrogen excretion. The nitrogen is then bioavailable for plant uptake. As heterotrophs, protozoans rely on eating other organisms for nutrition. Some protozoans consume entire organisms, while others take up their waste products. Their feeding habits make protozoans an important component of regulating bacterial populations. Although it is not entirely understood, bacterial feeding stimulates bacterial growth.

----

== '''Methods for Extraction:''' ==

Past methods for extraction focused heavily on culturing populations, but due to failure of some species to be cultured in a lab, this method is more rapidly being replaced by modern techniques. With advanced in genetic techniques, eDNA can now be amplified for use as an identifying tool. eDNA coupled with next generation sequencing has greatly aided in identifying and quantifying soil organisms that was previously unattainable with previous techniques.

File:Protistdiversity.png

2019-05-02T19:50:40Z

Cengel: