HYPOXIA - LaCoast.gov93.5 92.5 91.5 90.5 89.5 ≥ 75% ≥50% ≥25% ≤25% Sabine Lake Lake...

More Nitrogen Upstream, Fewer Filters DownstreamCaernarvon: A Case Study

WaterMarks Interview: John Day, LSU

www.lacoast.gov

Louisiana Coastal Wetlands Planning, Protection and Restoration News

HYPOXIATHE GULF OF MEXICO’S SUMMERTIME FOE

September 2004 Number 26

Contents

Hypoxia:The Gulf of Mexico’s Summertime Foe

More Nitrogen Upstream,Fewer Filters Downstream

Can Wetlands RestorationRevitalize Offshore Waters?

Caernarvon:A Case Study

What Lies Ahead for the Dead Zone?

WaterMarks Interview:John Day, LSU

Special thanks to Doug Daigle, Mississippi River Basin Alliance; Dugan Sabins,Louisiana State Hypoxia Committee; Ken Teague, U.S. Environmental ProtectionAgency; and Robert Twilley, Louisiana State University, for their assistance with this issue of WaterMarks.

For more information about Louisiana’s coastal wetlands and the efforts plannedand under way to ensure their survival, check out these sites on the web:

www.lacoast.gov www.btnep.org www.saveLAwetlands.org

SubscribeTo receive WaterMarks, e-mail [email protected] current meetings, events, and other news concerning Louisiana’s coastal wetlands, subscribe to the Breaux Act Newsflash, our e-mail newsletter, at:

www.lacoast.gov/newsletter.htm



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WaterMarks is published three times a

year by the Louisiana Coastal Wetlands

Conservation and Restoration Task

Force to communicate news and issues

of interest related to the Coastal

Wetlands Planning, Protection and

Restoration Act of 1990. This legislation

funds wetlands enhancement projects

nationwide, designating approximately

$50 million annually for work in

Louisiana. The state contributes

15 percent of the total cost of

the project.

About the Cover

Blue Runners, a common Gulf

species, have the ability to escape

from waters with low oxygen con-

tent. Other organisms in the Gulf

are not so fortunate.

Please address all questions,

comments and changes of address to:

James D. Addison

WaterMarks Editor

New Orleans District

US Army Corps of Engineers

P.O. Box 60267New Orleans, LA 70160-0267(504) 862-2201e-mail:

[email protected]

33

The Gulf of Mexico’sSummertime Foe

HYPOXIA


Each summer the richly productive

bottom waters off Louisiana’s coast are

transformed from a region of teeming

marine life into a vast area known as the

“Dead Zone,” which can encompass

up to 8,500 square miles. Within this

zone, the water near the bottom is

hypoxic—nearly depleted of oxygen.

The organisms living there must either

escape or die of suffocation. Its effects

are not yet fully defined, but the cause

of this phenomenon is clear. Simply

stated, the Gulf of Mexico is suffering

from too much of a good thing.

he Gulf owes its great productivityto abundant nutrients such asnitrogen, phosphorus and silica,

which enhance the growth of marine life.Nutrients encourage the growth of algae,a basic element of the Gulf food chain.More algae mean more plankton, moreshrimp and more fish. But algal productionis a good thing only up to a point. Thevolume of nutrients now delivered to theGulf is causing algae to grow too fast, withdeadly consequences for these waters.

Grey Snappers, like all other Gulf species,

prefer water with abundant oxygen and food.

The Dead Zone provides neither.

continued on page 4

T

Ph

oto

by

: N

OA

A


4

Hypoxic WatersAlgal cells flourish in the well-lit surface waters of the Gulf

each spring and summer, drifting to the bottom after death.Also, the algae are eaten by marine animals, which then pro-duce fecal matter that also drops to the bottom.There, theaccumulated organic matter begins to decompose.

This slow decay uses oxygen, depleting the oxygen livingorganisms at the bottom need. Eventually, unless the oxygenis replaced, the bottom waters become hypoxic—havingless than two milligrams of dissolved oxygen per liter.

Summertime StratificationDuring most of the year, oxygen-rich water reaches the

bottom and decomposition rates are normal. However, inspring and summer, when the algae bloom, the surfaceand bottom waters of the Gulf stratify into two layers.Warm, fresh and less dense water from the Mississippiand Atchafalaya rivers spreads out on the surface of thedeeper and colder Gulf water. Calm winds and warm sunshineprevent the layers from mixing thoroughly. The hypoxiabegins at the bottom, climbs toward the surface andspreads throughout the summer months. The lower watersmay not receive fresh oxygen from May until September.

The coming of autumn brings tropical storms, hurricanes,cold fronts and cooler water flowing into the Gulf. Thesemix the Gulf waters and replenish oxygen at the bottomonce more.

Life in the Dead ZoneDuring the summer months of low oxygen, while fish

and other mobile animals can escape the developing DeadZone, bottom dwellers that are attached to the ocean floorare doomed as the normal bottom ecosystem collapses.Significantly, when the autumn mixing brings oxygen levelsback to normal, the bottom communities do not have thechance to revive. Instead, the area tends to be re-colonized byonly a few short-lived species (such as polychaete worms)

Algal Bloom or Red Tide?

A “bloom” occurs when algae begin to rapidlyreproduce, forming billions of algal cells insurface waters, sometimes turning the watersa distinctive green. However, many types ofalgae, such as dinoflagellates, can producetoxins that poison the waters and kill almostall nearby organisms, producing a “red tide.”Even fish cannot always escape fast enough to survive this deadly menace.

Algae bloom

Algal cells die

and decompose

Decomposition results in

low dissolved oxygen

Fish, shellfish and other

organisms stressed

Nutrient-rich fresh water

layers over salt water

Chaetoceros, a

red-tide organism

Measuring and Monitoringthe Dead ZoneThe Dead Zone may reach from the Gulf floor to thesurface, but most often stretches upward from five to30 meters. It occurs over a changing area and set a recordin 2002 when it covered 8,500 square miles. The zoneforms primarily in the summer when the Gulf watersare calmer and the waters stratify easily. From spring toearly fall, scientists monitor its movement with oxygensampling equipment at various depths. Transects of thecoastal waters map the extent of the zone.

In a marine system with two distinct water layers, over-production by algae

may cause hypoxia, disrupting bottom communities and causing mobile

organisms to leave the area. Modified from National Center for Appropriate

Technology, www.ncat.org/nutrients/hypoxia/hypoxia1.htm.


5

that can establish themselves in theaftermath of the Dead Zone. Larger,longer-lived species (such as gastropods,bivalves, starfish, brittle stars and seaanemones) vanished from this part of theGulf 30-40 years ago. These new bottomcommunities fall far short of the normalecosystems in diversity, abundance orbiomass. Ken Teague of the U.S.Environmental Protection Agencydescribes it as “the seasonal eliminationof a vast area of productive habitat. Inthe Dead Zone, the original bottomcommunities were lost a long time ago.”

Often, the fish and shrimp that escape

the Dead Zone during the spring andsummer congregate at its edges. Theseconcentrations have caused manyLouisiana shrimpers to leave their nor-mal fishing areas to make a good catch.Other fishermen who take their catchesfrom the uppermost waters may not beaffected unless the Dead Zone reachesthe very top of the water column. In therare cases when this happens, the waterdoes not have a different appearance;it’s merely devoid of life.

Is This So Bad?Large hypoxic zones that occur at the

mouths of rivers are not unusual. Theycan be found in Long Island Sound,Chesapeake Bay, the Baltic Sea and theBlack Sea. However, the Gulf hypoxiczone is among the largest, in some yearscovering an area comparable to New Jersey.

Because research on the Dead Zone isstill relatively recent, scientists studyingthe Gulf know only the most fundamentalfacts about it. They can prove it exists andknow when and why it will form. But theyunderstand only some of its effects onecosystems. For example, while the catch ofbrown shrimp declined during the years ofgreatest hypoxia (1992-1997), scientists arenot certain that the Dead Zone caused it.

Still, although little is known at present,the Gulf ’s fish and shrimp ecosystems

show signs of stress. The Dead Zone isa prime suspect for:

• increasing mortality

• acting as a barrier to migration

• reducing suitable habitat

• increasing predation

• altering food resources

• disrupting life cycles, particularlyspawning and early life stages

No one yet knows if the Dead Zoneis a serious threat to coastal fishery andrecreation industries. Will there be apoint at which the enormous load ofnutrients carried to the Gulf causes the ecosystem to collapse? Only timewill tell. WM

The location of mid-summer hypoxic waters off the Louisiana coast can be predicted using data collected in prior years (1985–1999). Courtesy Nancy

Rabalais, Louisiana Universities Marine Consortium.

Dead Zone Frequency30.0

29.5

29.0

28.5

Lati

tud

e

93.5 92.5 91.5 90.5 89.5

≥ 75%

≥50%

≥25%

≤25%

Sabine LakeLake Calcasieu

Atchafalaya River

Mississippi River

Terrebonne Bay

50 km

Nu

trie

nt

Loa

d

Likely

Hypoxia

As nutrients in an ecosystem increase so does

productivity. But when too many nutrients cause

over-production, decomposing organic matter

may begin to use up the available oxygen. In

stratified waters, this can result in hypoxia.

Hypoxia, Productivity and Nutrient Load

Does the Dead ZoneMean Dead Fish?Massive fish kills in the Gulf are usuallyassociated with red tides, not the DeadZone, as fish can usually avoid thehypoxic zone and survive. Only whenthe oxygen-depleted waters are pushedonshore into bays and lagoons do fishbecome trapped. At its present size,the Dead Zone does not commonlyreach shore.

Longitude

Productivity


Scientists have found clues to the causes of the Dead Zone in both the Gulf and Mississippi River watershed. By examining

sediment cores taken offshore of Louisiana, they report that abundant nutrients and algal deposition, with resulting oxygen

depletion, were rare occurrences in the first half of the 20th century. This is consistent with the fact that it was only after 1970

that the hypoxia phenomenon became increasingly common. The researchers also see clues in several dramatic changes across

the 1.2 million-square-mile Mississippi drainage basin. These involve the landscape, agricultural and industrial practices, and

changes in the Mississippi itself.

The immense watershed of the Mississippi River system drains approximately 1.2 million square miles, covering parts of 31 states and two

Canadian provinces.

6

Gulf of Mexico

More Nitrogen Upstream, Fewer Filters Downstream

Missouri drainage basin

Upper Mississippi drainage basin

Ohio drainage basin

Tennessee drainage basin

Lower Mississippi drainage basin

Arkansas drainage basin

Hypoxic Zone


7

irst, during the last century, theMississippi River was constrainedwith levees to control flooding.

Nutrient-rich waters, which were previously spread by floods and naturaldiversions into filtering buffer zonesthroughout the floodplains of the vastriver basin, now flow directly to theMississippi delta with the nutrient load intact.

Second, between 1950 and 1996,there was a major increase in the use ofnitrogen fertilizer for agriculture. Duringthe same time, the nitrate load in theMississippi River also increased nearlythree-fold. While a small percentage ofthat increase is attributed to sources suchas treated municipal and industrialeffluents, livestock operations, atmos-pheric sources and runoff from urbanareas, scientists say an estimated 90percent of the increased nitrates havecome from agricultural runoff—waterdraining from fertilized fields.

Finally, the upstream landscape was significantly altered, primarily in1875-1925 and again in 1945-1960,by the destruction of riverside forestsand wetlands and by greatly improvingdrainage efficiency using ditches, burieddrainage tiles and/or culverts. In Ohio,Indiana, Illinois and Iowa, for example,80 percent of their wetlands are gone.These critical buffers once helped toconvert fertilizer nitrate into plant matterand atmospheric nitrogen. The loss ofthe forests and wetlands has effectivelyeliminated the basin’s capacity to filterout nutrients entering the river system.

“The extensive installment of underground tile drainage systems onfarmlands across the upper Midwestallows fields to dry more quickly duringthe spring thaw, but also to flush outfertilizer and pesticides into creeks andstreams that connect with the river,” saysDoug Daigle of the Mississippi RiverBasin Alliance. The improved drainagealso causes organic matter in the soil tooxidize more readily, releasing evenmore nitrogen.

By the time the river reaches thedelta, its nutrient load is overwhelming.Unfortunately, the last bastion of majorwetlands available on the river system hasbeen dramatically diminished by decadesof coastal erosion from both man-madeand natural causes. The river has beenleveed for flood protection and navigation,ensuring that the delta wetlands have nocontact with Mississippi River water.Because the wetlands no longer receiveinputs of sediment and nutrients from theriver, they are subsiding rapidly and beingconverted to open water bays and lakes.

This subsidence and erosion are exacer-bated by the navigation channels and oiland gas canals that have been cut throughthe wetlands.

Even if the wetlands of Louisianaexisted at their greatest natural capacityand were still connected to the river, it isnot likely that they could adequately filterthe nutrient load the river now carries.Ironically, the Louisiana coastal marshesare starving for the very nutrients thatflow by unimpeded—nutrients thatmove out to sea to cause a surfeit of algalgrowth and hypoxia in the Gulf. WM

F

Air Deposition

Forestry Practices

Agricultural Practices

The nitrate load in the Mississippi River has increased to three times what it was prior to 1950.

While a variety of causes account for a small percent of the increase, scientists say an estimated

90 percent of the jump is due to nitrates from agricultural and urban runoff.

Urban & Suburban

Activities Industrial Activities

Sources of Nutrient Load


8

According to the National Science and Technology Council’s “Integrated

Assessment of Hypoxia in the Northern Gulf of Mexico,” the river now carries

more than 1.6 million metric tons of nitrate each year. The abundance of

nitrogen, as well as phosphorus, carbon and silica, that feeds the algae in

the Gulf induces the seasonal appearance of hypoxia after the spring runoff.

Freshwater diversions (also known as reintroductions)

can use at least part of the nutrient load carried by the

Mississippi River. The two largest diversions are Davis

Pond and Caernarvon.

Can Wetlands Restoration Revitalize

OFFSHORE WATERS?Freshwater Diversion Structures

Baton Rouge

New Orleans

Gulf of Mexico

CaernarvonDavis

Pond

Mississippi River


9

t will be necessary to reduce thecurrent nitrogen load by 40 percentin order to return to pre-1970 levels.

But even a 20 or 30 percent reductionwould result in a 15 to 50 percentincrease in oxygen concentrations,which could have a significant positiveeffect on the marine ecosystems.

How can this reduction be broughtabout?There are two concurrent and comp-lementary sets of strategies proposed inthe Hypoxia Integrated Assessment bythe Committee on Environment andNatural Resources. The first calls forreducing the nitrogen loading to theriver and its tributaries. By altering farmmanagement practices, the agricultureindustry could reduce the river’s nitrateload by 0.9 to 1.4 million metric tons ayear. Some of these methods include:

• using crop rotation practices thatemploy perennials on 10 percent offarmland, effectively reducing thenitrate load by 0.5 million metrictons annually

• offering incentives to reduce theuse of agricultural fertilizer througha nitrogen-credit system similar tothe carbon-credit system applied tocarbon-emitting industries

• replacing aging tile drainage systemswith up-to-date systems that allowwater drained off fields to beretained and reused

• employing comprehensive nutrientwaste management for livestockoperations such as dairies

• applying precise nutrient applicationon fields, pinpointing only thoseareas in need of fertilizer

Doug Daigle of the Mississippi RiverBasin Alliance notes that “prairieperennials don’t require annual plowingor massive fertilizer inputs, and havemuch deeper root systems that hold soiland water together for longer periods.”He also points out that advanced tilingsystems “help farmers in times of drought,as well as reducing the flushing ofnitrates into waterways.”

The second proposed set of strategiesto reduce nitrates involves restoringwetlands throughout the Mississippidrainage basin. In their studies, JohnDay of Louisiana State University andWilliam Mitsch of Ohio State Universityare calling for the restoration of fivemillion acres of wetlands and 19 millionacres of riverside forest or grasslands in the Midwest—or 3 percent of thecurrent farmland in the basin. Restorationof these natural filtering systems couldreduce the Mississippi’s nitrate load by0.6 million metric tons per year, they say.

Can Louisiana’s Wetlands Help?Some experts believe that Louisiana’s

wetlands can play a part in reducing Gulfhypoxia. But there is a lack of consensusamong wetlands scientists on two issues.While some experts do not believe thatLouisiana’s wetlands are effective nitrogenremovers, others are concerned that thehypoxia problem will be transferred fromthe Gulf into the estuaries if river-waterreintroductions are used to move nutrient-rich waters into the delta system.

Ken Teague of the U.S. EnvironmentalProtection Agency notes, however, thatthe wetlands restoration projects currentlybuilt or planned were not designed toimprove the Mississippi’s water quality.In order to accomplish that, the flow ofwater through reintroductions and otherrestoration projects must be modified(see Caernarvon: A Case Study, page 10).

If water moves through the wetlandstoo quickly, there is little time for nutrientuptake. Therefore, projects that flushwater through the system need to bedesigned to maximize retention time.Robert Twilley of Louisiana StateUniversity points out that the benefits ofusing reintroductions to restore the healthof the wetlands should outweigh the risksof excessive production in the estuaries,most of which are too shallow to becomestratified. He says, “We need to be prudent in our use of reintroduced waterand not let the receiving basins retain thenutrient-rich water for too long. We alsoneed to recognize that some reintroduc-

tions will be in areas whose landscapesare no longer adapted to high flow, nothaving witnessed natural flows in thelast hundred years. However, it is veryimportant that we remain open-mindedto the responsible use of reintroductionsand learn how to adaptively manage therisk of over-production.”

If a reintroduction of water flow can be modified to further increase nitrogenuptake, then the reintroductions will notonly reduce the nutrient load, but theirability to meet their goal of restoringwetlands will also be enhanced.Significantly, as wetlands are restored,their filtering capacity increases, as doestheir ability to utilize more nutrientsthat would otherwise reach the Gulf.

Nevertheless, if Louisiana receives the full load of nutrients shed into theMississippi system, its wetlands cannotabsorb this tremendous burden.According to Mitsch and Day, even if allLouisiana reintroductions were openedto full capacity, sending 13 percent ofthe river flow over 1.2 million acres, itis estimated that only 5 to 10 percentof the total reduction needed could be achieved.

Reducing the river’s nutrient load toacceptable levels will require coordinatedefforts over the entire drainage basin.Until that is achieved, hypoxia, and itsimplied threat to Louisiana’s fisheries,will continue to visit the Gulf coasteach summer. WM

I


10

CAERNARVONA Case Study

The Caernarvon diversion has been moving Mississippi River water through wetland marshes since 1991.

The Caernarvon diversion, downstream from New Orleans, has been operating since 1991 with the goal of enhancing fish and

wildlife habitat, especially for oysters, by diverting fresh water, nutrients and a relatively small amount of sediment into

the Breton Sound estuary. The project was designed to create an optimum salinity gradient across the marshes between the

Mississippi River and the Mississippi River-Gulf Outlet, utilizing a flow schedule characterized by periods of moderate to low

flow and designed to re-establish the salinity levels known previously in the Breton Sound estuary.


11

eginning in 2001, John Day ofLouisiana State University and agroup of colleagues began a study

known as PULSES. The study tested thehypothesis that the flow of water througha reintroduction should mimic the natural seasonal flooding of the river system. Inother words, periods of high discharge(pulses) should be followed by little to no flow.

Working in cooperation with theCaernarvon project managers, the reintro-duction schedule was modified to includetimes of greatly increased flow. Before andafter each pulse, samples measuring sedi-mentation, nutrient uptake, chlorophylland salinity were gathered. The resultingdata clearly demonstrated that pulses havea major beneficial effect on the marshes.

• During times of high flow, the nutrient-rich and sediment-laden watersoverflowed the channels and spreadout, enriching wide areas of marsh.

• River water remained in the marsh fora longer period of time than duringprevious flows, allowing nutrientuptake to occur.

• Chlorophyll content increased,indicating that the introducednutrients led to increased algalgrowth.

Other non-PULSES data collected at Caernarvon indicate that an excessiveinflow of nutrient-rich fresh water andaccompanying low salinities might harmoyster beds or shrimp populations andstimulate excess algal growth in the estuary. Nevertheless, the PULSES findings were so strongly positive thatCaernarvon managers have adopted atemporary pulsed-flow managementschedule before the PULSES study hasbeen completed.

The sediments and nutrients that areprevented from reaching the Gulf by theCaernarvon reintroduction now bolstermarsh ecosystems instead of contributingto the nutrient load offshore. If the pulsingflow pattern employed at Caernarvon isused as a model for other reintroductionsalong the Mississippi, coastal wetlandsand the Gulf will both benefit. WM

B

The PULSES study modeled the Caernarvon discharge (black) on the natural pattern of

Mississippi River discharge (blue). The large pulses early in 2001 and 2002 reflect this

approach. (Modified from Day et al., 2003)

Comparison of Caernarvon and River Discharge

40,000

30,000

20,000

10,000

0

Mis

siss

ipp

i Riv

er

(m3

sec1 )

Ca

ern

arv

on

(m

3se

c1 )

1999 2000 2001 2002

400

300

200

100

0

The rate of water flow through the Caernarvon structure can be adjusted to optimize benefits

to the marshes.


12

When production increases in an ecosystem, organic matter, such as algal cells and fecal pellets, increases. This situation can lead to hypoxia

when decaying bottom organic matter depletes oxygen and water stratification blocks oxygen replenishment. Upwelling oxygen-rich water or

destruction of the stratification can alleviate this problem. Courtesy of the U.S. Environmental Protection Agency.

What lies ahead for the

DEAD ZONE?

river fresh water

healthy benthic community

(worms, snails, bivalves, crustaceans)

organic matter decomposed

& oxygen consumed

zooplankton

phytoplankton

fecal pellets

dead cells

oxygen

oxygen

blocked

escape

mortality

pycnocline

organicmaterial

lighter, fresher, warmersurface layer

heavier, saltier, coolerlower layer

nutrients,

sediments &

organic carbon

oxygen oxygen

nutrients,

sediments &

organic carbon

What Causes Hypoxia?


13

• What are the best ways to improvethe Mississippi’s water quality andreduce the river’s nutrient load?

• What future effect will the DeadZone have on Gulf fisheries?

• Can all partners in the watershedcooperate to improve the quality ofthe water in the Mississippi?

Reducing the Nutrient LoadA national task force, the Mississippi

River—Gulf of Mexico WatershedNutrient Task Force (the Hypoxia TaskForce), has devised an action plan(www.epa.gov/msbasin, click onChallenges) to mitigate hypoxia in thenorthern Gulf of Mexico. Its goalsinclude:

• develop a budget proposal

• establish subbasin committees

• determine research and nutrient-reduction strategies

• expand monitoring programs in thebasin and the Gulf

• complete a reconnaissance study

• identify nutrient point sources

• begin wetland/buffer restorationprojects

• implement best management practices

Among subsequent initiativeslaunched by universities and basinstakeholders, William Mitsch of OhioState University and John Day ofLouisiana State University have devel-oped a watershed-wide plan to improvethe water quality of the Mississippi,reduce its nutrient load and diminishthe effects of hypoxia.

The recently completed $150,000study, funded by the state of Louisianaand the U.S. Army Corps of Engineers,complements the goals of the Task Forceaction plan. It documents the loss ofextensive water-filtering buffer zonesalong the Mississippi and its tributariesand recommends an ambitious plan torestore tens of millions of riverside wetland and forest acres at a cost of tens of billions of dollars.

Despite the enormity of this cost,when compared to the $8 billion neededto restore 1.4 million acres in the FloridaEverglades, this restoration plan actuallycosts substantially less per acre. Besidesrestoring buffer zones, the plan alsoadvocates establishing a nitrogen-creditsystem with incentives for the agriculturalindustry to reduce its application ofnitrogen-based fertilizers.

Under the current Farm Bill, theFarm Security and Rural InvestmentAct of 2002, two important Departmentof Agriculture conservation strategiesare already being implemented. Marginalwet croplands are being taken out ofproduction and converted to wetlandsby the Natural Resources ConservationProgram, and the Farm Service Agencyhas worked to cover thousands of acresof easily eroded land with grass or trees,producing riverside buffer zones.

Future FisheriesBetter research is essential to

predicting the long-reaching effectshypoxia may have on Gulf ecosystemsand Louisiana fisheries. Revisedresearch strategies are now exploring the consequences of the Dead Zone bygathering fisheries data in new ways.Instead of relating catch data to the portwhere the catch arrives, some fishingvessels have been equipped with global-

positioning transponders that record theexact location where the catch is actuallymade. These “trip-ticket” data shouldprove invaluable in determining thehealth and forecasting the future of theGulf fisheries.

Watershed CooperationThe national Hypoxia Task

Force supports establishing subbasin committees to coordinate research andactions to reduce nutrients. For example,Louisiana has joined Arkansas,Mississippi, Missouri and Tennessee in the Lower Mississippi SubbasinCommittee. This group is identifyingdemonstration watersheds where thebest management practices for nutrientreduction can be developed and showcased.

Avoiding new hierarchies, both the national and subbasin committeesare utilizing existing organizations,programs and activities to further thegoals of the action plan. WithinLouisiana, the State Hypoxia WorkingGroup has participants from organiza-tions involved in Breaux Act coastalrestoration, along with the Louisianadepartments of Environmental Qualityand Agriculture and Forestry, theGovernor’s Office of Coastal Activitiesand the Mississippi River Basin Alliance.

“We have a unique situation where allof these agencies are working togethertoward a common goal,” said DuganSabins of the state committee.

Given the complexity of the hypoxia problem, the vast extent of the watershedinvolved and the severity of the potentialconsequences, scientists hope thatfunding for research and resolution is provided before full recovery isimpossible. WM

It is clear that, unless the nutrient load entering the northern Gulf is reduced,

destructive hypoxia will appear each summer. However, three fundamental

issues remain for scientists and regional stakeholders to address:


14

WaterMarks: How big a problemis this Dead Zone? Is hypoxiasomething that’s been around foryears and we only just noticed it?

DAY: I think this is a very serious problem, a growing problem that will onlyget much, much worse. Louisiana has twobig problems, wetlands loss and hypoxia.They are related, with thepotential in the coming decadefor us to see catastrophic results.

WaterMarks: So far thefisheries, the shrimpersand the recreationalfishing industries havenot been adverselyaffected by the DeadZone. So why is this so important?

DAY: There is a growing consensus, astrong expectation that this problem isgoing to become a critical one. How longwill it be before the Dead Zone is so bigthat the fish simply run out of habitat toescape to? How long will it be before thecoast is so fragmented that there is no coastleft? We don’t know if the problem will justget worse and worse gradually or if we willreach a critical threshold when the entireLouisiana fishery will collapse.

It’s wrong to focus on just Louisiana.This is a national problem, a distributedproblem and we need a distributed solution.We are all unified by this huge river system;we are all part of the problem; and we canand should be part of the solution. If wecan reverse the trend of the last 50 years,reduce the hypoxia, reverse or at least slowthe coastal wetlands loss, maybe we willbe lucky enough to never find out how biga disaster this might have become.

WaterMarks: Are the farmers toblame for this mess?

DAY: It would be a huge mistake to blamefarmers for this problem. Nobody oughtto be pointing a finger at anyone else.This is our problem in the same way thatLouisiana’s wetlands loss is our problem,the nation’s problem. We were achievingnational goals, agricultural production and

flood control, as we createdthese problems. Now weneed to make new nationalgoals to solve these prob-lems. We need to worktogether with the farmersand say “Hey, look, weneed you to use only 2 or3 percent of your farmlandto make a first filter forthe fertilizer runoff.”

This is a win-win solution. The farmer savesmoney on fertilizer and gets

a green area with more birds and otherwildlife. A system for creating nitrogencredits in the same way as carbon creditsare used to prevent global warming wouldhelp even more.

We would all get cleaner local watersources with all the health benefits of that.We would get flood reduction too, becausethe wetlands absorb the excess rainfall andsome of the over-bank waters.

WaterMarks: Is it more importantto solve the problem upstreamfirst? How important are theLouisiana wetlands in solving this problem?

DAY: Most of the problem is in the upperparts of the basin. Maybe 5 to 10 percent ofthe problem could be solved in Louisianabut I think it is important for Louisiana tobe able to say it is doing its part. The delta

wetlands can act as the “polisher” inremoving the last bit of excess nitrogen,making the load of the river water thatheads out to the Gulf in the range of 0.5mg/liter, right what it should be.

WaterMarks: Can river-water reintroductions help? How can we be sure we aren’t going tomake the estuaries hypoxicinstead of the Gulf?

DAY: Reintroductions are the way to gofor this problem. I am not too worriedabout hypoxia in the estuaries. They aretoo shallow and mix every day. There is nostratification. The danger to the estuariesis the possibility of algal blooms, possiblytoxic ones. But the data at Caernarvonshow that it is possible to get a significantdrop in nitrogen levels across the areabetween the reintroduction and the estuary.

WaterMarks: If reintroductions canhelp, what is the best way touse a reintroduction?

DAY: The best way to use a reintroduction isto send the water through in pulses, morewater in a little time rather than a moderateflow of water all the time. Pulsing getsmore water up and over the marsh surface,causing more sediment to be depositedand more nitrogen to be taken up. RobertTwilley of Louisiana State University hasfound that denitrification is much moreefficient when the water leaves the chan-nels, because the water is warmed by 5 to10 degrees Celsius. The oyster beds alsobenefit because the low-salinity water isnot constantly in the channels but is outon the marsh. When I began the pulsingstudy at Caernarvon, the preliminary datawere so overwhelmingly positive that the

WaterMarks Interview: John Day, LSU


15

study was not even finished before pulsingwas adopted as the best managementplan for that reintroduction.

WaterMarks: Does it look like there will be any funding forthese projects, or for furtherresearch?

DAY: Right now we have piecemealstudies and we are trying to link theseall together. I would like to see a largefederal, state and private program, anintegrated program, stretching fromMinnesota down to Louisiana, doingresearch, buying land for conversion towetlands, promoting nitrogen credits forfarmers. I’m optimistic about it. We havean enormous opportunity to bring allplayers together in a win-win situationto move us down the road towardssolving this problem.

WaterMarks: Don’t we alreadyknow enough about the causesof the Dead Zone? Why shouldwe do more research?

DAY: To those who say that we don’tneed any more research, I answer thatthe research here is not just academicstudy without practical results. It is doneon the ground, meaning that each time astudy is done, that wetland becomes partof the solution. Each study tells us moreabout where a wetland needs to be placedrelative to the fertilizer source, how big itneeds to be and how the water shouldflow through it for the best results.

Understanding where the wetlandsshould be is as important to the solutionas knowing that we need them. A wetlandthat is improperly placed may attractducks and other wildlife but it doesn’tact as a filter for the adjacent farmland.

WaterMarks: Assuming thatyour big plan goes into effect,how many years might it bebefore we see any improvement?What is going to be happeningduring those years?

DAY: We’re talking about a bunch oflittle steps that may need to be spreadout over three decades of wetlandrestoration. But there will be a directrelationship to the hypoxia of the Gulf.Every little bit is going to help. But,just as importantly, the people in therest of the watershed will be able to say“Hey, there are more birds around, the

local drinking water is cleaner, theflooding is not as severe and we spendless money on fertilizer. We helped ourneighbors in Louisiana too, and thatmeans we can buy fish and shrimp for dinner!” WM

Dr. John Day is a Distinguished Professor

in the Department of Oceanography and

Coastal Science at Louisiana State University.

Department of the Army

New Orleans District, Corps of Engineers

P.O. Box 60267New Orleans, Louisiana 70160-0267

Official Business


First Class Mail

Postage and Fees Paid

U.S. Army Corps of Engineers

New Orleans District

Permit No. 80


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HYPOXIA - LaCoast.gov93.5 92.5 91.5 90.5 89.5 ≥ 75% ≥50% ≥25% ≤25% Sabine Lake Lake...

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