Personal Home Page for: mjohnson
| Instructor: Dr. Eugene Takle Email: gstakle@iastate.edu Office: 3010 Agronomy |
Assistant: Mike Taber Email: mtaber@iastate.edu Office: 3010 Agronomy |
Sample questions for the upcoming exam are now available on ClassNet. Choose "Blk1: Self Test" to see sample questions. Remember, this is not a graded assignment.
We have some latest news releases, in particular, information about the latest cracks in the Antarctic ice shelf. See the latest news release page for additional information.
Also, Warren Dolphin in Biology wanted us to make this announcement: I would appreciate your mentioning in your class that there are some openings left for the Biology field trip to Costa Rica to be taken May 10 through 24. We will visit pristine rain forests, cloud forests in the mountains, and the beaches on the Pacific coast under the guidance of English-speaking biologists from the faculty of the University of Costa Rica. Students interested in the trip should contact me immediately by E-mail at wdolphin or by phone at 294-8595. Cost for the trip is estimated at $1,600, including airfare. Students will receive 1 credit in Biology 394 for a pre-trip seminar and 2 credits for the trip. Students who took the trip last year felt that it was the experience of a lifetime.
| Assignments | Due Dates | Standards | Points Possible | ||
|---|---|---|---|---|---|
| Unacceptable Standards | Acceptable Standards | ||||
| Informal Internet discussion on lecture topics | Electronic dialog
homepage or access each discussion page from lecture pages |
February 17 | Minimum 5 entries | 5 | |
| Responded to at least 2 other students | 5 | ||||
| Received at least on response from another student | 5 | ||||
| Post-lecture activity | 1:1 Overview lecture | January 15 | No response made; repeat of someone else's response | Temperature comparison reported as requested | 7 |
| Post-lecture activity | 1:2 Evolution of the Earth's atmosphere | January 17 | No discussion of cloud movement, or incorrect direction described | Correct recognition of different directions of movement at different locations | 8 |
| Web discussion of ethical issue | Block 1:$3.00/gallon for gasoline | February 17 | Restates someone else's position; shallow thinking, idea unrelated to topic; disrespectful of other views | Presents an idea not already given; reveals senior-level thinking; promotes discussion; respects other views | 5 |
| Web discussion of block topic | Block 1:Iron solution | February 17 | Restates someone else's position; shallow thinking, idea unrelated to topic; disrespectful of other views | Presents an idea not already given; reveals senior-level thinking; promotes discussion; respects other views | 10 |
| Review paper of a journal article | Submit paper topic on Atmospheric chemistry | February 3 | Reference is from a secondary, unrefereed source | Reference is from a primary, refereed source | No points |
| Submit paper on Atmospheric chemistry | February 10 | ||||
| Relying on information from course text or unrefereed source | Summary of a refereed paper; indicates student originality | 5 | |||
| Not presenting material beyond that presented in class | Demonstrates senior-level library research; synthesizes article with class materials | 4 | |||
| Paper consists of phrases cut from journal article | Paper demonstrates senior-level analysis and interpretation of research results | 4 | |||
| Lacking organization (no headings or paragraph divisions, lack of continuity) | Well organized; paper flows nicely | 4 | |||
| Having numerous grammatical mistakes | Few or no grammatical mistakes | 4 | |||
| Having numerous misspellings | Few or no misspellings | 4 | |||
| Sub-total points for paper | 25 | ||||
| Exam 1 | 30 | ||||
| Total points for block | 100 | ||||
One of the newest trends the Midwest has found itself in
(according to a Missouri researcher I do believe) is the fact
that we may be entering into a little ice age for the next
fifteen to twenty years, due to changing jet streams and other
changing upper air patterns. Whether or not this is caused by global
warming, who knows (as of yet). But maybe this is one of the
possibilities of average global warming--relatively small
areas of localized cooling.
First Name:
Matthew
mjohnson@cumulus.geol.iastate.edu
Agricultural sources of atmospheric methane compromise a large
portion of the annual methane budget. Within these sources,
cattle serve as one of the major contributors (the numerics of
which are highly disputable). Two distinct processes account
for the release of methane from cattle: The first being as a
byproduct of ruminant digestion and the second being methane
emissions from excreta. Thorough understanding of these
processes is necessary if a reduction in methane production
rates is to be accomplished.
Looking at ruminant digestion first, the typical beef and
dairy cow each produce about 60 to 71 kg and 109 to 126 kg
of methane annually (Johnson, 1995). Equivalently, these
figures translate into an average of approximately 6% of the
animals gross energy intake (GEI) is used to produce methane
(Johnson, 1995). The goal of much nutrition research is to
reduce this number which subsequently decrease methane emissions
while increasing nutrition efficiency. Multiple factors
contribute to ruminant methane production but two principle
mechanism are responsible for most methane production variance.
First, the magnitude and type of carbohydrates fermented in
the reticulorumen plays a vital role and second, the production
ratio of propionic acid to acetic acid is a principal indicator
of total methane production.
The carbohydrates ingested by an animal will affect methane
production. As the carbohydrate fraction of any fiber or starch
is increased, methane production will decrease. Thus,
feedstuffs such as beetpulp tend to reduce methane emissions and
subsequently the percent of GEI used to produce methane.
Another method of reducing methane emissions is to increase the
percentage of grain in the animal's diet. U.S. feedlots
commonly feed a 90% grain ration, yet the percent of GEI
consumed by methane production falls to 3 to 4%, which
translates into methane emission rate decreases.
Additional methods which decrease methane emissions include
pelleting and grinding forages. This process can lead up to a
40% reduction in methane production (Johnson, 1995). The
addition of lipids to an animal's diet also can lead to a
reduction in methane production, typically a 29% decrease in
methane production results from lipid addition to feedstuffs.
Similar results occur with ionophore addition to feedstuffs.
Alteration of ruminal microbes can lead to a 50% reduction in
methane emissions, however, obtaining results this encouraging
requires a specialized situation, namely the animal must be on a
barley diet with a defaunation of the rumen (Johnson, 1995).
The second bovine-based methane source is excreta, of which
the magnitude released is considerable lower than aructated
methane. In a U.K. study of a 165 head dairy operation, the
average animal generated 105 kg
annually through ruminant processes versus 0.22 kg
annually from excreta (Jarvis, 1995).
Jarvis, Lovell, and Panayides calculated methane emission rates
from dung collected from various animals including dairy and
beef cattle. Dung pats representative in volume and area of
soil coverage to actual dung piles were placed in air tight
containers and 10 ml samples of the air were periodically
removed from the containers through a syringe and Suba seal and
then analyzed with a gas chromatograph.
Results indicate that methane emission is usually highest
immediately after deposition and decreases to insignificant
levels after ten days. Total emissions from a single pat
average 1702 mg for a
grazing dairy cow foraging upon grasses and clover.
Pats originating from a housed dairy cow being fed a silage and
concentrates ration averaged 716 mg .
Thus suggesting the possibility of dietary implications
upon methane emissions. A study by Lodman et. al. revealed that
methane emissions per kg of dung were 7.5 times higher when
animals were fed a high grain ration (Jarvis et.al., 1995).
Note, the increase in methane emissions from the dung pat does
not counter the decrease in aructated methane when grain intake
is increased due to the relative magnitudes of the average
emission rates.
Methane emission rate decreases from cattle are possible, and
with dung methane emissions being approximately only 0.2% of
all bovine generated methane, it becomes obvious that decreases
in aructated methane are likely to yield greater decreases in
total methane emissions from cattle.
Jarvis, S. C., R. D. Lovell and R. Panayides, 1995: Patterns of
methane emission from excreta of grazing animals.
Soil. Biol. Biochem., 27(12), 1581-1588.
Johnson, K. A. and D. E. Johnson, 1995: Methane emissions from
cattle. J. Anim. Sci., 73, 2483-2492.
Name: Gene Takle
Return to the top of the page
Completed Work
In this section, the electronic submissions are appended. Students can see the
work they have accomplished and view "In Response to" comments from other
students, world experts and the instructor. The next version will allow
students to re-work assignments which do not meet the standards or are
unsatisfactory to the student.
Name: Matthew Johnson
email: shotgun@iastate.edu
Response to: Mike Tannura (mtannura@iastate.edu)
Abstract:
Name: Johnny Burkhart
email: johnnyf@iastate.edu
Response to: Matt Johnson
Abstract:
Concerning the little ice age events:
My understanding is that these little ice age events are represented
by periods of global cooling and warming during a large scale
glaciation. For example, the events which led to the formation of
the Bemis, Altimont, and Algona moraines here in Iowa along the
Des Moines lobe. Can these events of cooling be localized or must
they be global short period trends?
For all:
Does it not seem odd that there is evidence that we are possibly
entering a "little ice age" while everyone is talking about global
warming?
Name: Matthew T. Johnson
email: mjohnson@cumulus.geol.iastate.edu
Response to: Michael T. Robert (mikebob)
Abstract:
The basics (extremely brief version)
to High and Low development center
around divergence and convergence of air in
the upper and lower atmosphere, this figure should help.
When air converges in the lower troposphere,
(or diverges in the upper atmosphere) Vertical motion
results and reduces surface pressure. Forming a low at
the surface.
The reverse is true in the situation of High
pressure.
Now, what causes air convergence
and divergence, well, obviously the wind
flow in the upper atmosphere (the jet streams
at approximately 250 - 200 millibars (mb). And
also the 500 mb flow. And these large scale
flows are ultimately driven by temperature
gradients.
Orographic features can also play a role
in cyclogenesis. When air streams traverse
the Rocky mountains from west to east
conservation of momentum (angular, and vorticity
(spin of the air)) will produce a low pressure
center east of the Rockies. The lows produced
in this matter often eventually travel through
Iowa.
Doc Title: Analysis of bovine methane emissions
Last Name: Johnson
Title: undergraduate
email: mjohnson@cumulus.geol.iastate.edu
Affiliation: ISU
Abstract:
Meteor/Env St/Agron 404/504
2/10/97
email: gstakle
Response to: M. Johnson (mjohnson)
Abstract:
I am testing the assessment page on the
instructor portfolio. Your grade on the
first paper was 25/25. Good work!!
Now take a tour
of the Global Change course. When you are finished, click the right arrow
below to continue.
