£os,Transactions, American Geophysical Union, Vol. 81, No. 17,April 25,2000, Pages 181, 186

Coastal Sedimentary Research ExaminesCritical Issues of National and Global Priority

Fig. J. Aerial photo ofNorth Myrtle Beach, South Carolina. This figure shows the northern end of a6o-mile long stretch of heavily developed shoreline characterized IJy hotels and private homes onnarrow sandy barriers backed IJy tidal marshes and lagoons. Much of the waterfront development wasdestroyed in 1989 by Hurricane Hugo, but has since been rebuilt. This figure illustrates one of themajor national and global coastal problems-lack ofplanning or regulation ofshoreline devel­opment in high-hazard zones. (Photo by D. B. Scott, J996).

An international conference was held recent­ly in Honolulu, Hawaii, to examine and planfor coastal sedimentary research in the UnitedStates and globally. Participants agreed thatsedimentary coastal environments constitute acritical national and global resource that suf­fers widespread degradation due to humanimpacts. Moreover, human population growthand inappropriate development in the coastalzone are escalating public asset losses due tocoastal hazards and placing large numbers ofcommunities at growing risk (Figure I).

Consensus was reached on a number of spe­cific scientific priorities, which include bettercorrelation of local relative Holocene sea-levelhistories, identifying mass balance in littoralsediments, extending the instrumental recordwith sedimentary archives, understanding the"biolithology" of carbonate reefs on the meterscale, tracking geochemical flux throughcoastal waters and substrates, and placingmore emphasis on why coastal variabilityexists rather than simply characterizing it.Withthe understanding that coastal environmentalchange is a critical national and internationalresearch priority, the participants agreed thatan international workshop on coastal forecast­ing should be convened to define a vision forthe future of coastal sedimentary research andidentify critical areas of enhanCed investiga­tion within a research framework.

The Crowded Coast

The U.S. coastal zone is one of the nation'sgreatest environmental and economic assets[Ocean Studies Board, 1999].A national migra­tion toward coastal towns and villages occurredin the last half of the 20th century and contin­ues today, and now over 80% of the Americanpopulation lives within 50 miles of the coast.By 2010 population density along ocean shoreswill be 400 people per square mile comparedto less than 100 per square mile for the rest ofthe nation. Fourteen of the country's 20 largesturban corridors are along the nation's coastand a major portion of U.S. economic infrastruc­ture is near or on the ocean. Globally, the fig­ures in these categories are similar. Over50%-some 3.2 billion people-live along acoastline today, but this figure is expected torise to 75% by 2025 [Hinrichsen, 1999].

This burgeoning population depends onlimited natural resources. Overfishing, mineraldepletion,sewage disposal, aquifer deficien­cies, vulnerability to coastal hazards, andbeach and wetland loss are critical issues

Copyright 2000 by theAmerican Geophysical Union0096/3941/8117/181/$03.00.

throughout the nation and the world. The nat­ural health of the coastal environment isendangered and is a focal point for federaland local policy development. In truth, how­ever, many management policies do not pro­vide adequate solutions, often because theylack a scientific basis.

We live in a time of sea-level highstand withaccelerated rises projected ahead. Environ­mental change -gradual, rapid, andcatastrophic-is an integral feature of highsea levels.To understand the history andprocesses driving coastal environmentalchanges, research on a range of spatial andtemporal scales is needed. High-resolutiongeologic records of coastal change canextend the instrumental record to the recentpast, and former intervals of sea-levelhighstand can help us understand the present.

Coastal sedimentary research is highly rele­vant to understanding coastal environments.Most coastal ecosystems depend upon sedi­mentary substrates and sedimentary transportprocesses for critical nutrient flux and trophic

energy. Sedimentary processes are typicallynon-linear and highly complex, and hencethey are easily disrupted. Our understandingof the structure and function of sediment­dependent environments (that is, reefs,wetlands,estuaries, beaches, etc.) is improving butremains inadequate.The ability to forecastcoastal environmental change can be improvedwith focused research.

No Sponsor forthe Academic Community

The academic core of the U.S. coastal sedi­mentary research community has sufferedfrom a lack of planning for its scientificfuture.The field has long been characterizedby individual research efforts, but there arefew unified and system-level researchproducts that cross disciplinary lines. Majoraspects of how and why coastal sedimentaryprocesses interact across spatial and temporalscales remain unknown.With the exceptionof a small number of research efforts (e.g., theNational Science Foundation's [NSF] LandMargin Ecosystem Research Program), thereis a lack of significant progress in understand­ing the linkages and interrelationships amongand between shoreline environments.

This situation is now hindering researchfunding. For instance, within NSF,coastalsedimentary research is left without a clearproponent in either the Earth or Oceansdirectorates [FUMAGES, 1998].Within theNational Oceanic and Atmospheric Adminis­tration, the Federal Emergency ManagementAdministration and, to some extent, the Envi­ronmental Protection Agency and NASA,funding is available for spatial and temporalanalysis of coastal trends, but these efforts typ­ically focus on what environmental tenden­cies occur and often do not answer why orhow coastal change happens.

The Coastal and Marine Geology Program(CMGP) of the U.S. Geological Survey ischarged with establishing the geologic frame­work of the U.S. coastal and marine regions[Ocean Studies Board, 1999]. However, theCMGP is not driven by external proposal sub­mission, and instead it responds to requeststhat originate outside the research sector.Hence, within the national academic commu­nity, the true value of coastal sedimentaryresearch is underestimated. At the NSF,programmatic lines typically stop at thecoastal zone.As a result, the true nature ofcoastal sedimentary research as an amphibi­ous discipline cannot easily be accommodat­ed.An important exception to this is theMARGINS "Source to Sink Project" [Nittrouerand Driscoll, 1999],which is nascent butpromises significant advances in understand­ing sedimentary flux and partitioning. Howev­er, the MARGINS program will primarily focuson only two study sites: New Zealand andNew'Guinea. Hence, MARG[NS does not repre­sent a comprehensive programmatic solutionfor the U.S. community.

Community Policy Consensus

Coastal environmental value is recognizedin the missions of many federal agencies.However, research by the academic core istypically underutilized.The logical source offunding for fundamental research in coastalsedimentary processes and their consequencesis NSfHowever, NSF's programmatic structuredoes not promote advances in coastalsedimentology.As a result, the true power ofthis field lies untapped despite the nationaland global need. Participants agreed that thecommunity of U.S. coastal sedimentaryresearchers must develop a vision and aresearch plan, both fundamentally and intenns of societal relevance.The plan shouldintegrate a spectrum of traditional Earth andOcean Science fields to effectively mobilizeand focus research in coastal change.Theplan must provide direction for understandingwhy and how environmental processes andpatterns occur and interact across temporaland spatial scales.The plan shouldrecommend continued support for gifted indi­vidual researchers who will lead significantbreak- throughs in coastal sedimentaryresearch. [n addition, a new strategic tool isrequired. Funding agencies must support inte­grated multidisciplinary teams of investigators

working in specific coastal cells using modelsand field experiments that utilize observation­al, mapping, and drilling technologies.lnterna­tional collaboration has been the keystone ofimportant progress in the past,and linkageswith overseas investigators must be an integralpart of new advances. Conference participantspledged their support for this effort.

Community Science Consensus

A consensus was reached on the followingscience issues. [nstrumental records of sea-levelchange can be connected to high-resolutiongeologic archives spanning the last 1-2 k.y.Thiswill improve understanding of sea-level patternsand controlling factors such as El Nino/South­ern Oscillation,steric effects, and the dynamicsea surface. PAGES/WICZ programs in this areashould be supported by U.S. efforts.

Regional synthesis and correlation of localrelative Holocene sea-level histories is critical.This is fundamental to separating the individ­ual roles of forebulge collapse, neotectonics,and climate effects along the U.S. and globalcoastline. Isolating these signals will enhanceour ability to forecast specific impacts of futuresea-level variability. Studies of the timing andvariability of last interglacial (and earlier) sealevels should emphasize dated samples lack­ing open system behavior.Thermally ionizedmass spectrometry (rIMS) Th-Pa methodolo­gy is useful at critical sites defining sea-levelpivot points. Efforts should focus on publica­tion of high-quality examples with high-reso­lution measurements of indicative sea-levelposition and chronology.

Mass balance littoral sediment budgetsshould be emphasized in future studies ofcoastal change. Uttle is known of the residencetimes and exchange rates of coastal sedimentsin most types of littoral environments. Fieldexperiments must be designed to minimizeundefined residual budget components.

The geologic framework of U.S. and globalcoastal systems must be defined, includingsiliciclastic, carbonate, and mixed sedimenta­ry systems.This effort should focus on under­standing why variability exists and must notstop at defining what that variability is. Improvedunderstanding of framework variability canthen be correlated to modem dynamic process­es of sediment/water interaction, includingsedimentary fluxes, to establish a holistic andsystemic understanding of coastal variability.Carbonate reefs are a special global treasure;however, we lack a true understanding of thecontrols on their structure and evolution.More is known of their morphology on thekilometer scale and their biology on the cen­timeter scale, but less is known of the biolitholo­gy on the meter scale.Workers can unify thisdisparate understanding by focusing on themeter to dekameter scale of biolithologic,ecologic, and geochemical variability.Thisapproach will help to better understand theimpact of increased ocean acidity, shifts inprevailing currents and sea surface tempera­tures,and changes in the quantity andgeochemical character of terrestrial inputs.

Coastal ecologies and water quality dependupon sedimentary environments. Geochemicalflux through the water column and sedimenta­ry substrates should be the target of focusedfield experiments to delineate uptake, diagene­sis,sequestration,and release of biogeochemi­cally active chemical constituents. Finally, therewas consensus among the community toextend the vision and planning advancesmade in Honolulu with an international work­shop on Coastal Forecasting.The workshop'sgoal should be to define a vision for the futureof coastal sedimentary research and to identifycritical areas of enhanced investigation withina national research framework.

The research conference, Non-Steady Stateof the Inner Shelf and Shoreline: CoastalChange on the Time Scale of Decades toMillennia in the Late Quaternary, was heldNovember 9-12, 1999, at the University ofHawaii in Honolulu. (View the agenda andapproximately 90 papers at http://soest.hawaiLedu/Coastal_Conf/).

Acknowledgments

The Hawaii conference was funded by theNational Science Foundation (EAR9908594),the U.S. Geological Survey's Coastal andMarine Geology Program, the Hawaii SeaGrant College, and [nternational GeologicalCorrelation Programme (IGCP) Project No.437, Coastal Change During Sea Level High­stands.The International Geosphere/Biosphere Project OGBP), Past Global Environ­mental Changes (PAGES), and Land OceanInteraction in the Coastal Zone (LO[CZ)programs also participated.

References

Hinrichsen, D., Coastal WateTli of the World: Trends,Threats, and Strategies, Island Press,Washingtono.C.,275 pp., 1999.

Ocean Studies Board,Science for Decision Making,Commission on Geosciences, Environment, andResources, National Research Council, NationalAcademy Press, Washington o.C., 113 pp., 1999.

Future of Marine Geology and Geophysics(FUMAGE.S),Proceedings of a Workshop December5-7, /996 in Ashland Hills, Oregon,edited by P. Bakerand M. McNutt, 264 pp., 1998 (see http://www.joi odp.org/FUMAGE.S/FUMAGE.S.html).

Nittrouer, C.,and N. Driscoll,Source to Sink, MARGINSNewsletter No.3, p. 2-3,1999.

Authors

Chip Fletcher, Department of Geology andGeophysics, University of Hawaii, Honolulu,USA; John Anderson, Department of Geologyand Geophysics, Rice University, Houston,Tex.,USA; Keith A. W. Crook, Hawaii UnderseaResearch Laboratory, University of Hawaii,Honolulu, USA; George Kaminsky. WashingtonDepartment of Ecology, Olympia,Wash., USA;Piers Larcombe, Marine Geophysical Laborato­ry,James Cook University,Townsville,Australia;

Colin VMurray-Wallace, School of Geosciences,University of Wollongong, New South Wales,Australia; Frank Sansone, Department ofOceanography, University of Hawaii, Honolulu,USA; David B. Scott, Centre for Marine Geology,

Dalhousie University, Halifax, Nova Scotia,Canada; Stan Riggs, Department of Geology,East Carolina University, Greenville, N.C., USA;Asbury Sallenger; US. Geological Survey, Cen­ter for Coastal Geology, SI. Petersburg, Fla.,

USA; Ian Shennan, Department of Geography,University of Durham, UK.; E. Robert Thieler;US. Geological Survey,Woods Hole, Mass., USA;John E Wehmiller; Department of Geology,University of Delaware, Newark, USA