9. Production dislocations are likely to have a significant impact in the Nation’s balance of trade.
Agriculture is the only sector that has consistently produced a positive balance in international
trade. Additionally, agriculture receives no credit for its beneficial contributions, for example,
eliminating malaria (previously an endemic disease in the Midwest), from the region.

10. Federal agencies must pursue this matter with an even hand, affecting all segments of the
contributing population(s), agencies and programs.

11. More data are needed on the extent, severity and impacts of Gulf hypoxia, as well as a broad
look at potential solutions.

Other Concerns:

The reports do not teflect:

1. Shrimp trawls damage to the benthic community Which causes a break inthe food chain.
2. The impacts fishing / harvesting have on fish populations.

3. Farmers/producers use of precision agriculture and Certified Crop Advisors in the application
of fertilizer, pesticides, and herbicides.


“flood proofing” or the navigation improvements might be undone, it is not unrealistic to
recognize that the time, effort, and funds that contributed to the disturbed ecology of the Gulf
may need to be matched in restoring the ecology of the GoM.

TOPIC 6: EVALUATION OF ECONOMIC COSTS AND BENEFITS OF METHODS |
FOR REDUCING NUTRIENT LOADS TO THE GULF OF MEXICO

1, The recommended solution is a pragmatic one. If implemented, what effect will it have on
the extent of the hypoxic zone? Critical nitrogen source areas need to be identified and targeted
for action in any program to reduce nitrogen loads to receiving waters.

GENERAL COMMENTS

1, To what extent docs channelization and levees contribute to hypoxia? What are the impacts
from isolating the river from adjacent floodplain wetlands and impacts from rapidly delivering
nutrients to the gulf through the channelized river?

2. ‘What will be the impact to Gulf of Mexico hypoxia once all states meet water quality
” standards set by the Clean Water Act and court mandates? =~

3. What impacts would inchiding conservation work completed since the 1985 Farm Bill have
on conclusions in the six assessments?

4, There are concems about the size of the hypoxic zone. Is it getting larger or amalier? Are the
7,000 square miles a one-time perturbation, as a result of the 1993 and 1995 floods, or is the zone
actually enlarging?

5. The correlation between nitrogen fertilizer use in the Corn Belt and the nitrogen loads in the
Mississippi River do not prove cause-and-effect, While the use of nitrogen was increasing, the
population of the Mississippi River Basin was also increasing. .
6. There is a lack of data to support the contention that the hypoxia zone has caused any adverse
impacts upon the Gulf of Mexico fisheries—cither commercial or sports. Reports should be
prepared to show the benefits derived from restoring the ecology.

7. If nitrogen loads are reduced, by whatever means, it is important to recognize that the time lag
between such curtailment and any ecological improvement in the hypoxic area may not be
reflected over the short term—it may take several decades to see improvements in the Gulf of
Mexico.

8, Extreme reductions in agricultural nitrogen use in the Corn Belt may well lead to production
relocations to other parts of the United States or to other nations. This would potentially shift the
problems from the Gulf of Mexico to some other locations. It would also work hardships on the
farmers and rural communities and economies of the upper Midwest.


DEPARTMENT OF AGRICULTURE
OFFICE OF THE SECRETARY
WASHINGTON, D.C. Z0z50

UL 30 R99

Dr. Donald Scavia

Chief Scientist

National Ocean Service

National Oceanic and Atmospheric Administration
1305 East-West Highway, Room 13508

SSMC 4 .

Silver Spring, Maryland 20910

Dear Dr. Scavia:

We epplaud your efforts and those of your fellow researchers in developing the six reports on the
Committee on Environment and Natural Resources.

The enclosed comments are provided from several Department of Agriculture agencies asa ~

follow-up to the research briefings that were provided on hypoxia at the June 1999 meeting held

in Memphis, Tennessee. We look forward to any response you or your colleagues may have to

these comments. . . a

Thank you for the opportunity to provide our comments.

Sincerely,

GLENDA L. HUMISTON

Deputy Under Secretary .

Natural Resources and Environment .

Enclosure

AN EQUAL OPPORTUNITY EMPLOvER aln £-O0.4 Ls


COMMENTS on the CENR-HYPOXIA REPORTS

TOPIC 1: CHARACTERIZATION OF HYPOXIA

1. Data presented seemed to indicate that the extent of the hypoxia area may be ephemeral or has
rapidly changing boundaries. This makes the area difficult to define in size and also suggests
response to periodic changing events or conditions.

2. The finding that hypoxia did not exist historically was not convincing. Whether or not
hypoxia is a naturally occurring condition must be definitively answered if the general public is
expected to embrace the hypoxia issue as a problem and actively, willingly participate in seeking
solutions.

3. Additional data are needed to track location and size of the area. This data could be used, in
canjunction with other weather or seasonal events, to determine what causes the hypoxia zone to
change.

4, The hypoxic zone doubled in size after the Mid-West floods of 1993. The zone did not start
gradually shrinking again until 1998. The factors that changed and caused this doubling in size
maust have persisted and been readily available during the hypoxic season for the next 5 years.

” Would nitrogen persist over that long a period of time? Would carbon be more likely to persist
and with the annual addition of sediment, nitrogen, and phosphorus, be able to sustain the zone at
7,000 square miles? Would this carbon enrichment be sufficient to keep the process fueled and
stable for 5 years?

5, The changes brought about by the 1985 Farm Bill, namely compliance plans emphasizing
conservation tillage, should have had significant effects on the Redfield ratio. Erosion rates
should have been much lower than under a similar storm under pre-Farm Bill conditions leading
to lower delivery of silica and higher deliveries of carbon (crop residues) and soluble :
phosphorus. (Some scientists say that the Mississippi is e sediment-starved river.) Much of the
crop residues and "new" organic matter added to the topsoil would have enriched the
floodwaters. The large quantities of water would have mobilized a much larger quantity of
carbon than would have occurred under less extreme events. Much of this carbon would have
"been in the form of suspended detritus, with significant quantities unattached to sediment.

6. Water quality monitoring during the flood stages of the 1993 event was pretty sketchy
because of not being able to reach gauging stations. No records exist on the amount of carbon
delivered during the ‘93 floods. Wouldn't the addition of plentiful supplies of carbon plus other
nutrients, such as soluble phosphorus have been the cause of the zone’s growth in '93?

7. Another consideration relating to carbon is the erosion and loss of 30,000 acres of wetlands
along the coast of Louisiana as well as major diversions from the Atchafalya River.
Coincidentally, the hypoxia zone does not extend much west of the Louisiana coast. The


nutrients added from these eroding areas should be quantitatively addressed and their effects
mentioned in the assessment.

TOPIC 2: ECOLOGICAL AND ECONOMIC CONSEQUENCES OF HYPOXIA.

1. The “total system collapse” scenario is supported by comparisons between the Gulf of Mexico
and hypoxia related fisheries impacts in the Baltic Sea, Black Sea and Sea of Japan. We should
determine whether the conditions causing hypoxia in these locations are the same as in the Gulf.
‘We should also determine whether there are conditions unique at those locations that prevents
fisheries from recovering (i.e. over-fishing) or favors maintaining hypoxia conditions (i.e. water
temperature, water movement or mixing, and constant loading of carbon into the system).

TOPIC 3: FLUX AND SOURCES OF NUTRIENTS IN THE MISSISSIPPI-
ATCHAFALAYA RIVER BASIN

1. Non-agriculture, non-point sources of pollution (i.e. urban fertilizer use and septic systems)
contribution to total nutrient load needs to be determined.

2. Need to determine the percent of naturally occurring nutrient load in the system

3. The assessment did not provide answers to the percent of edge of the field nitrogen loss that
actually reaches the gulf.

TOPIC 4: EFFECTS OF REDUCING NUTRIENT LOADS TO SURFACE WATERS
WITHIN THE MISSISISIPPI RIVER BASIN AND THE GULF OF MEXICO

1. The presenters recommended, and we agree, that the data presented in this topic assessment
should not be used to set target levels for nutrient loading.

2 The river/gulf system has a tremendous buffering effect to change making it difficult to
predict the total impact or when changes will occur in response to nutrient reduction. More
modeling is needed to provide greater insight on where to direct financial and technical
assistance.

TOPIC 5: REDUCING NUTRIENT LOADS, ESPECIALLY NITRATE-NITROGEN, TO
SURFACE WATER, GROUNDWATER, AND THE GULF OF MEXICO

1. The authors suggest drain tile spacing as one component of the nitrogen load reduction
program. An estimate of future tile drainage in the Mississippi River Basin is needed. Programs
to encourage redesign can be developed.

2. The Corps of Engineers has been “flood proofing” the lower basin for over a century, and has
spent several millions of dollars to build levees and navigation structures, which have been ~
generally successful. Unfortunately, these activities did not take account of possible or likely
effects on the ecology of the Gulf of Mexico. While it is unrealistic to suppose that either the