Читать реферат по английскому: "Biomass Essay Research Paper Many factors contribute" Страница 1

(Назад) (Cкачать работу)

Biomass Essay, Research Paper

Many factors contribute to the diversity of life in an environment. The

availability of nutrients and sunlight, along with other factors that play a

pivotal role in determining what and how much life an area can sustain. While

studying the Second Law of Thermodynamics, it came to my attention that the

classical pyramid shape of the producer, C1, C2, C3, biomass pyramid did little

to take into account the amount of detrital input. I hypothesized that the

amount detrital input greatly effected the number of C1, C2, and C3 consumers

and thus the overall biodiversity of an ecosystem. Further, if you could find a

test-bed where detrital input was the only real difference between two similar

ecosystems you would find that organisms of each ecosystem would be adapted to

the peculiar conditions. This adaptation would lead you to find vast differences

in the taxonomic groups associated with each ecosystem. With this in mind, I

first set out to find two similar ecosystems were I could test this hypothesis.

Second, to sample, categorize and compare the diversity of these ecosystems

along taxonomic lines. Next, I planned to use several of the widely accepted

diversity indexes (Simpson?s Index, Shannon?s Index the Chi-Square Test) to

compare statistically, the diversity of my ecosystems. Scientific Law states

that in order to test the effects of one factor in an equation you must

eliminate all other factors . In order to test the detrital base as the limiting

factor, all other limiting agents must be eliminated. In a field experiment this

is technically impossible; though it is possible to come close by choosing two

ecosystems that are very similar. In order to keep this experiment as simple as

possible the ecosystem chosen had to be nearly self contained and small. The

smaller and more contained the ecosystem the less chance for outside input that

could destroy our results. Alazan and Bernaldo creek provided just the type of

test-bed needed for this experiment. Both are third order creeks in the same

geographic area that are subject to same weather and climate conditions, but

differ considerably in the amount of detritus available. (Fleet) Procedure

Alazan creek is a third order stream that feeds into the Angelina River. It is

bordered by several species of indigenous trees that form a small gallery of

overhanging branches. This gallery consisted of (pine, oak, sweetgum trees) and

was limited to a range of about twenty five feet from the edge of the stream.

These gallery trees are surrounded by open cattle grazing fields covered by

short grasses and an occasional scrub brush. Alazan creek ranged from ten to

fifteen feet wide with a water depth of six inches to two feet. The water was

generally clear, and flowed at a brisk ten to twelve mile per hour pace. The

creek bottom was primarily sand with little or no mud. Turbitity was low to

moderately low and the creek had a high oxygen content. Detrital input was low

and limited to leaves from the gallery trees. Bernaldo creek is a third order

creek that similarly empties into the Angelina River. Bernaldo creek differs

substantially in that it is entirely surrounded by typical east Texas piney

woods. (The particular area that samples were taken from appeared to be

relatively low lying in comparison to the surrounding woods.) It is likewise ten

to fifteen feet wide but, is considerably deeper at four to eight feet than

Alazan creek. Bernaldo creek flows at a much slower pace, approximately six to

eight miles per hour. The bottom of Bernaldo creek consists largely of mud,

which gives the water a darker color. Overall turbitity is high and overall

oxygen content is low. Human disturbance at both creeks was minimal. Although at

Alazan creek the surrounding area was used for grazing animals and at Bernaldo

creek the sight that specimen were actually taken from was a concrete washout

bridge. Both sights appeared to be in a flood plain, one that probably becomes

inundated on a monthly basis during the rainy season. Weather conditions at the

time of the sampling were typical of east Texas in spring, therefore unusual

conditions caused by atypical weather can be eliminated. What it boils down to

is, the only difference between the two creeks was the amount of detrital

material available and the conditions predicated by this difference. Starting

the week of February 8, 1999 daily 1p.m. trips were made by four lab groups to

both Alazan and Bernaldo creeks. During these trips observations were made on

terrain, topography, climate, vegetation and specimens were taken from several

spots along each creek. The specimen were taken by netting at various depths and

locations. The nets used had a pore size of approximately 2 millimeters on four

sides and a canvas bottom (see diagram 1) and were attached to poles 8 feet

long. In order to take a sample, a student placed the scoop nets open end up

stream and allowed the water and it?s contents to be strained. The nets were

then quickly pulled from the water and the samples collected were immediately

taken to opened garbage bags and sorted through. (see diagram 2) When any living

creature was found, it was placed in a collection jar (labeled for the

particular creek it was taken from) to be examined later. The collection jars

contained an organic die known as FAA. FAA is a combination of

Похожие работы