Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation

Autores
Hassan, Gabriela Susana; Diaz, Marisel Carina
Año de publicación
2021
Idioma
inglés
Tipo de recurso
documento de conferencia
Estado
versión publicada
Descripción
Frustulefragmentation is one of the major taphonomic factors affecting diatompreservation in Pampean shallow lakes. This has been demonstrated both bycontemporary and fossil taphonomic studies, although little is known about thecauses of frustule breakage and its environmental significance. Field studiesalong modern environmental gradients showed a low but significant correlationbetween dissolution and fragmentation, suggesting that debilitation of thefrustule by silica dissolution can be the cause of diatom fragmentation.Reworking of sediments by wind action have also be suggested as a possibleexplanation for the observed fragmentation patterns. To evaluate the relativeimportance of chemical and physical causes of diatom fragmentation, three laboratoryexperiments were conducted to test for 1) the effect of physical agitation, 2)the effect of chemical dissolution, and 3) the joint effect of both variableson diatom fragmentation. Physical agitation was simulated by subjecting diatomsamples to lineal shaking at 250 rpm during 30 days. Chemical dissolution wastested by mixing diatom assemblages with solutions of different concentrationsof NaCl and NaHCO3, and pH 10 during 20days. The joint effect of both processes was tested by diluting diatomassemblages in salt solutions and subjecting them to agitation during 20 daysat 250 rpm. In all cases, aliquots of each assemblage were sampled at initialand final experimental times and taphonomically analyzed through theapplication of fragmentation and dissolution indices. Significant differencesin fragmentation indices were observed both in dissolution alone and combinedexperiments, but no differences were found in the agitation alone essay. In allcases, dissolution and fragmentation indices were correlated, suggesting acausal relationship among them. Overall, our results suggest that the debilitationof the diatom frustule by chemical dissolution may be the main cause of theobserved fragmentation patterns in surface sediments of Pampean shallow lakes.
Fil: Hassan, Gabriela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
Fil: Diaz, Marisel Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
2nd Workshop on Actualistic Taphonomy
Rio Grande do SUl
Brasil
Universidade Federal do Rio Grande do Sul
Materia
Diatoms
Fragmentation
Experimental taphonomy
Pampean lakes
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/214492
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/214492
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentationHassan, Gabriela SusanaDiaz, Marisel CarinaDiatomsFragmentationExperimental taphonomyPampean lakeshttps://purl.org/becyt/ford/1.5https://purl.org/becyt/ford/1Frustulefragmentation is one of the major taphonomic factors affecting diatompreservation in Pampean shallow lakes. This has been demonstrated both bycontemporary and fossil taphonomic studies, although little is known about thecauses of frustule breakage and its environmental significance. Field studiesalong modern environmental gradients showed a low but significant correlationbetween dissolution and fragmentation, suggesting that debilitation of thefrustule by silica dissolution can be the cause of diatom fragmentation.Reworking of sediments by wind action have also be suggested as a possibleexplanation for the observed fragmentation patterns. To evaluate the relativeimportance of chemical and physical causes of diatom fragmentation, three laboratoryexperiments were conducted to test for 1) the effect of physical agitation, 2)the effect of chemical dissolution, and 3) the joint effect of both variableson diatom fragmentation. Physical agitation was simulated by subjecting diatomsamples to lineal shaking at 250 rpm during 30 days. Chemical dissolution wastested by mixing diatom assemblages with solutions of different concentrationsof NaCl and NaHCO3, and pH 10 during 20days. The joint effect of both processes was tested by diluting diatomassemblages in salt solutions and subjecting them to agitation during 20 daysat 250 rpm. In all cases, aliquots of each assemblage were sampled at initialand final experimental times and taphonomically analyzed through theapplication of fragmentation and dissolution indices. Significant differencesin fragmentation indices were observed both in dissolution alone and combinedexperiments, but no differences were found in the agitation alone essay. In allcases, dissolution and fragmentation indices were correlated, suggesting acausal relationship among them. Overall, our results suggest that the debilitationof the diatom frustule by chemical dissolution may be the main cause of theobserved fragmentation patterns in surface sediments of Pampean shallow lakes.Fil: Hassan, Gabriela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Diaz, Marisel Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina2nd Workshop on Actualistic TaphonomyRio Grande do SUlBrasilUniversidade Federal do Rio Grande do SulUniversidad de Rio Grande do Sul2021info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/conferenceObjectWorkshopJournalhttp://purl.org/coar/resource_type/c_5794info:ar-repo/semantics/documentoDeConferenciaapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/214492Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation; 2nd Workshop on Actualistic Taphonomy; Rio Grande do SUl; Brasil; 2021; 23-23CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.ufrgs.br/taas/wp-content/uploads/2021/07/Abstracts-2nd-TAAS-Workshop-on-Actualistic-Taphonomy-in-South-America.pdfinfo:eu-repo/semantics/altIdentifier/doi/10.5281/zenodo.5114543Internacionalinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-03T09:54:34Zoai:ri.conicet.gov.ar:11336/214492instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-03 09:54:34.471CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
title Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
spellingShingle Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
Hassan, Gabriela Susana
Diatoms
Fragmentation
Experimental taphonomy
Pampean lakes
title_short Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
title_full Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
title_fullStr Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
title_full_unstemmed Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
title_sort Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation
dc.creator.none.fl_str_mv Hassan, Gabriela Susana
Diaz, Marisel Carina
author Hassan, Gabriela Susana
author_facet Hassan, Gabriela Susana
Diaz, Marisel Carina
author_role author
author2 Diaz, Marisel Carina
author2_role author
dc.subject.none.fl_str_mv Diatoms
Fragmentation
Experimental taphonomy
Pampean lakes
topic Diatoms
Fragmentation
Experimental taphonomy
Pampean lakes
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.5
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Frustulefragmentation is one of the major taphonomic factors affecting diatompreservation in Pampean shallow lakes. This has been demonstrated both bycontemporary and fossil taphonomic studies, although little is known about thecauses of frustule breakage and its environmental significance. Field studiesalong modern environmental gradients showed a low but significant correlationbetween dissolution and fragmentation, suggesting that debilitation of thefrustule by silica dissolution can be the cause of diatom fragmentation.Reworking of sediments by wind action have also be suggested as a possibleexplanation for the observed fragmentation patterns. To evaluate the relativeimportance of chemical and physical causes of diatom fragmentation, three laboratoryexperiments were conducted to test for 1) the effect of physical agitation, 2)the effect of chemical dissolution, and 3) the joint effect of both variableson diatom fragmentation. Physical agitation was simulated by subjecting diatomsamples to lineal shaking at 250 rpm during 30 days. Chemical dissolution wastested by mixing diatom assemblages with solutions of different concentrationsof NaCl and NaHCO3, and pH 10 during 20days. The joint effect of both processes was tested by diluting diatomassemblages in salt solutions and subjecting them to agitation during 20 daysat 250 rpm. In all cases, aliquots of each assemblage were sampled at initialand final experimental times and taphonomically analyzed through theapplication of fragmentation and dissolution indices. Significant differencesin fragmentation indices were observed both in dissolution alone and combinedexperiments, but no differences were found in the agitation alone essay. In allcases, dissolution and fragmentation indices were correlated, suggesting acausal relationship among them. Overall, our results suggest that the debilitationof the diatom frustule by chemical dissolution may be the main cause of theobserved fragmentation patterns in surface sediments of Pampean shallow lakes.
Fil: Hassan, Gabriela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
Fil: Diaz, Marisel Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina
2nd Workshop on Actualistic Taphonomy
Rio Grande do SUl
Brasil
Universidade Federal do Rio Grande do Sul
description Frustulefragmentation is one of the major taphonomic factors affecting diatompreservation in Pampean shallow lakes. This has been demonstrated both bycontemporary and fossil taphonomic studies, although little is known about thecauses of frustule breakage and its environmental significance. Field studiesalong modern environmental gradients showed a low but significant correlationbetween dissolution and fragmentation, suggesting that debilitation of thefrustule by silica dissolution can be the cause of diatom fragmentation.Reworking of sediments by wind action have also be suggested as a possibleexplanation for the observed fragmentation patterns. To evaluate the relativeimportance of chemical and physical causes of diatom fragmentation, three laboratoryexperiments were conducted to test for 1) the effect of physical agitation, 2)the effect of chemical dissolution, and 3) the joint effect of both variableson diatom fragmentation. Physical agitation was simulated by subjecting diatomsamples to lineal shaking at 250 rpm during 30 days. Chemical dissolution wastested by mixing diatom assemblages with solutions of different concentrationsof NaCl and NaHCO3, and pH 10 during 20days. The joint effect of both processes was tested by diluting diatomassemblages in salt solutions and subjecting them to agitation during 20 daysat 250 rpm. In all cases, aliquots of each assemblage were sampled at initialand final experimental times and taphonomically analyzed through theapplication of fragmentation and dissolution indices. Significant differencesin fragmentation indices were observed both in dissolution alone and combinedexperiments, but no differences were found in the agitation alone essay. In allcases, dissolution and fragmentation indices were correlated, suggesting acausal relationship among them. Overall, our results suggest that the debilitationof the diatom frustule by chemical dissolution may be the main cause of theobserved fragmentation patterns in surface sediments of Pampean shallow lakes.
publishDate 2021
dc.date.none.fl_str_mv 2021
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/conferenceObject
Workshop
Journal
http://purl.org/coar/resource_type/c_5794
info:ar-repo/semantics/documentoDeConferencia
status_str publishedVersion
format conferenceObject
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/214492
Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation; 2nd Workshop on Actualistic Taphonomy; Rio Grande do SUl; Brasil; 2021; 23-23
CONICET Digital
CONICET
url http://hdl.handle.net/11336/214492
identifier_str_mv Experimental taphonomy of freshwater diatoms: discriminating between chemical and physical causes of frustule fragmentation; 2nd Workshop on Actualistic Taphonomy; Rio Grande do SUl; Brasil; 2021; 23-23
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://www.ufrgs.br/taas/wp-content/uploads/2021/07/Abstracts-2nd-TAAS-Workshop-on-Actualistic-Taphonomy-in-South-America.pdf
info:eu-repo/semantics/altIdentifier/doi/10.5281/zenodo.5114543
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
application/pdf
dc.coverage.none.fl_str_mv Internacional
dc.publisher.none.fl_str_mv Universidad de Rio Grande do Sul
publisher.none.fl_str_mv Universidad de Rio Grande do Sul
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
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repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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