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Elsevier, Continental Shelf Research, 6(31), p. 527-538, 2011
DOI: 10.1016/j.csr.2010.12.008
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A process-based model for erosion of macoma balthica-affected mud beds
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Abstract
Modelingtheeffectofbiotaonsedimentdynamicsisadifficulttask.Inthispaperwere-analyze experimentalresultsof Willows etal.(1998) on theeffectsof Macoma balthica on sedimenterosion. A process-basedframeworkisproposed,fullycompatiblewithaphysicaldescriptionoferosionprocesses in caseofnobiogenicinfluences.Thebedisrepresentedbyaflufflayerontopofasubstrate.Acharacteristic featureoftheframeworkisthatthesedimentisrepresentedbyaprobabilitydensitydistributionforthe criticalshearstress,allowingforTypeIandTypeIIerosion. M. balthica increasesthesedimentmassinthe fluff layer.Thisincreaseisdeterminedbyconsideringtheactionradius,theoverlapoffeedingareas,and the feedingrateperanimal.Thecalibratedactionradiusandfeedingratewereintherangeasfoundinthe literature.Thedistributionofsedimentovertheerodibilityclassesandtheerosionrateparameterare hardly influencedatall.Duetooverlappingfeedingareas,theeffectisnon-linearwithdensityofthe animals.Themodelresultsareincloseagreementwiththemeasuredresults,suggestingthatnofurther formulationsofbiologicaleffectsareneededtosimulatetheexperimentsof Willows etal.(1998). In nature,othereffectslikedisruptingthebiofilmbygrazingcanbeofimportanceandshouldbeincludedin a laterstage.Thisstudyemphasizesthecrucialroleofsedimentavailabilityandtheeffectofbiotaonit. This aspectneedsmoreattentioninfutureexperiments.Theproposedmodelturnedouttoworkwellfor the effectsof M. balthica and offersopportunitiestoincludeotherbiogeniceffectsinaprocess-basedway as well. ; Modelingtheeffectofbiotaonsedimentdynamicsisadifficulttask.Inthispaperwere-analyze experimentalresultsof Willows etal.(1998) on theeffectsof Macoma balthica on sedimenterosion. A process-basedframeworkisproposed,fullycompatiblewithaphysicaldescriptionoferosionprocesses in caseofnobiogenicinfluences.Thebedisrepresentedbyaflufflayerontopofasubstrate.Acharacteristic featureoftheframeworkisthatthesedimentisrepresentedbyaprobabilitydensitydistributionforthe criticalshearstress,allowingforTypeIandTypeIIerosion. M. balthica increasesthesedimentmassinthe fluff layer.Thisincreaseisdeterminedbyconsideringtheactionradius,theoverlapoffeedingareas,and the feedingrateperanimal.Thecalibratedactionradiusandfeedingratewereintherangeasfoundinthe literature.Thedistributionofsedimentovertheerodibilityclassesandtheerosionrateparameterare hardly influencedatall.Duetooverlappingfeedingareas,theeffectisnon-linearwithdensityofthe animals.Themodelresultsareincloseagreementwiththemeasuredresults,suggestingthatnofurther formulationsofbiologicaleffectsareneededtosimulatetheexperimentsof Willows etal.(1998). In nature,othereffectslikedisruptingthebiofilmbygrazingcanbeofimportanceandshouldbeincludedin a laterstage.Thisstudyemphasizesthecrucialroleofsedimentavailabilityandtheeffectofbiotaonit. This aspectneedsmoreattentioninfutureexperiments.Theproposedmodelturnedouttoworkwellfor the effectsof M. balthica and offersopportunitiestoincludeotherbiogeniceffectsinaprocess-basedway as well.