Multiple phyla, one time resolution? Similar time averaging in benthic foraminifera, mollusk, echinoid, crustacean, and otolith fossil assemblages

Geology, Journal Year: 2022, Volume and Issue: 50(8), P. 902 - 906

Published: May 9, 2022

Abstract Time averaging of fossil assemblages determines temporal precision paleoecological and geochronological inferences. Taxonomic differences in intrinsic skeletal durability are expected to produce mismatch between co-occurring species, but the importance this effect is difficult assess due lack direct estimates time for many higher taxa. Moreover, burial below taphonomic active zone early diagenetic processes may alleviate taxonomic disintegration rates subsurface sediments. We compared across five phyla major carbonate producers a sediment core from northern Adriatic Sea shelf. dated individual bivalve shells, foraminiferal tests, tests isolated plates irregular regular echinoids, crab claws, fish otoliths. In spite different architecture, mineralogy, life habit, all taxa showed very similar varying ~1800 ~3600 yr (interquartile age ranges). Thus, remains echinoids crustaceans—two groups with multi-elemental skeletons assumed have low preservation potential—can still undergo extensive mixing comparable that mollusk shells. The median ages differed by as much ~3700 yr, reflecting species-specific timing seafloor colonization during Holocene transgression. Our results congruent sequestration models invoking minimize among These together variability production can overrule effects determining resolution multi-taxic assemblages.

Language: Английский

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ONSHORE-OFFSHORE TRENDS IN THE TEMPORAL RESOLUTION OF MOLLUSCAN DEATH ASSEMBLAGES: HOW AGE-FREQUENCY DISTRIBUTIONS REVEAL QUATERNARY SEA-LEVEL HISTORY

Palaios, Journal Year: 2023, Volume and Issue: 38(3), P. 148 - 157

Published: March 31, 2023

Abstract Surficial shell accumulations from shallow marine settings are typically averaged over centennial-to-millennial time scales and dominated by specimens that died in the most recent centuries, resulting strongly right-skewed age-frequency distributions (AFDs). However, AFDs modern offshore (outer shelf uppermost continental slope) still need to be explored. Using individually dated shells (14C-calibrated amino acid racemization), we compared along an onshore-offshore gradient across southern Brazilian shelf, with sites ranging inner shallow-water (< 40 m) offshore, deep-water (> 100 settings. The duration of averaging is slightly higher deeper water environments, AFD shapes change depositional profile. due dominance millennia (median age range: 0–3 ka). In contrast, on outer slope, symmetrical left-skewed following Last Glacial Maximum 15–18 changes observed properties AFDs—increased median decreased skewness, but only increased temporal mixing—likely reflect sea level concurrent depth-related biological productivity. These results suggest a passive margin subject post-glacial sea-level changes, magnitude time-averaging assemblages less variable profile than assemblage ages AFDs.

Language: Английский

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Temporal scales, sampling designs and age distributions in marine conservation palaeobiology

Geological Society London Special Publications, Journal Year: 2023, Volume and Issue: 529(1), P. 1 - 39

Published: March 29, 2023

Abstract Conservation palaeobiology informs conservation and restoration of ecosystems by using the fossil record to discriminate between baseline novel states assess ecosystem response perturbations. Variability in time-scale palaeobiological data can generate patterns that either exaggerate or mute magnitude biotic changes. We identify two approaches remedy challenges associated with mixing post-impact transformation stratigraphic depth time. First, combining surface death assemblages both (1) preserved subsurface historical layers (2) living better resolve nature shifts than within-core surveys live–dead analyses alone. Second, post-mortem age distributions skeletal particles their preservation are not only informative about resolution time averaging but also timing changes abundance producers. High youngest cohorts is a null expectation disintegration burial dynamic. When this dynamic accounted for, benthic invertebrates from Holocene sediments often reveal high volatility, prolonged turn-offs production pervasive regime obscured raw record.

Language: Английский

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CHALLENGES OF CONSERVATION PALEOBIOLOGY: FROM BASELINES TO NOVEL COMMUNITIES TO THE NECESSITY FOR GRANTING RIGHTS TO NATURE

Palaios, Journal Year: 2023, Volume and Issue: 38(6), P. 259 - 263

Published: June 23, 2023

Research Article| June 23, 2023 CHALLENGES OF CONSERVATION PALEOBIOLOGY: FROM BASELINES TO NOVEL COMMUNITIES THE NECESSITY FOR GRANTING RIGHTS NATURE MARTIN ZUSCHIN Department of Paleontology, University Vienna, Josef-Holaubek-Platz 2, 1090 Austria email: [email protected] Search for other works by this author on: GSW Google Scholar Author and Article Information Publisher: SEPM Society Sedimentary Geology Received: 17 May Accepted: 24 First Online: 27 Jun Online ISSN: 1938-5323 Print 0883-1351 Copyright © 2023, (Society Geology) PALAIOS (2023) 38 (6): 259–263. https://doi.org/10.2110/palo.2023.020 history Cite View This Citation Add to Manager Share Icon Facebook Twitter LinkedIn Email Permissions Site ZUSCHIN; NATURE. 2023;; doi: Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input auto suggest filter your All ContentBy SocietyPALAIOS Advanced Conservation Paleobiology (CP) was formally introduced more than 20years ago (Flessa 2002) as a field that deals with the application theories analytical tools paleontology biodiversity conservation, but has multifaceted roots go back at least into 1970s (Dietl Flessa 2009; Dillon et al. 2022). More thirty years ago, it already evident anthropogenic impacts had changed modern marine environments so profoundly ecological research alone does not catch undisturbed baselines (e.g., Pauly 1995; Jackson 1997; 2001; Kowalewski Pandolfi et... You do have access content, please speak institutional administrator if you feel should access.

Language: Английский

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Inferring time averaging and hiatus durations in the stratigraphic record of high‐frequency depositional sequences

Sedimentology, Journal Year: 2021, Volume and Issue: 69(3), P. 1083 - 1118

Published: Aug. 22, 2021

Abstract A sequence stratigraphic framework predicts that time averaging and hiatus durations will be long at times of fastest sea‐level rise. This prediction does not necessarily apply to environments where carbonate production keeps up with rise undetected hiatuses decouple short‐term from long‐term sedimentation rates. The taphonomic clock, however, which measures the residence skeletal particles in mixed layer, can estimate duration if rate alteration is slow endure exposure layer. Here, calibrated by using evidence bivalves a metre‐scale Holocene Adriatic Sea. In this sequence, transgressive molluscan lags, maximum‐flooding zone shell bed bivalves, highstand bryomol assemblages were all deposited under similar rates ( ca 0.01 0.03 cm year −1 ) exhibit millennial averaging. Median ages valves stained pyrite cemented high‐magnesium calcitic micritic envelopes exceeding 1000 years indicate that: (i) these authigenic processes are subsurface zones reducing conditions (with prolonged sulphate reduction ions sourced dissolved shells surface zones); (ii) micrite precipitation prolongs disintegration half‐lives exhumed decades millennia. high abundance valves, envelopes, composite (encrusters borers colonizing grains) thus identifies concentrations time‐averaged >1000 years. upcore decrease alteration, coupled temporally‐constant averaging, indicates temporal decline sediment exhumation was compensated burial produced molluscs.

Language: Английский

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Ideas and perspectives: Human impacts alter the marine fossil record

Biogeosciences, Journal Year: 2024, Volume and Issue: 21(9), P. 2177 - 2188

Published: May 3, 2024

Abstract. The youngest fossil record is a crucial source of data documenting the recent history marine ecosystems and their long-term alteration by humans. However, human activities that reshape communities habitats also alter sedimentary biological processes control formation archives recording those impacts. These diverse physical, geochemical, disturbances include changes in sediment fluxes due to alluvial coastal landscapes, seabed disturbance bottom trawling ship traffic, ocean acidification deoxygenation, removal native species, introduction invasive ecosystem engineers. novel modify sedimentation rates, depth intensity mixing, pore-water saturation state, preservation potential skeletal remains – parameters controlling completeness spatiotemporal resolution record. We argue humans have become major force transforming nature ways can both impede improve our ability reconstruct past ecological climate dynamics. A better understanding feedback between impacts on offers new research opportunities tools for interpreting geohistorical ongoing anthropogenic transformation ocean.

Language: Английский

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Stratigraphic paleobiology

Paleobiology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 18

Published: March 7, 2024

Abstract Stratigraphic paleobiology uses a modern understanding of the construction stratigraphic record—from beds to depositional sequences sedimentary basins—to interpret patterns and guide sampling strategies in fossil record. Over past 25 years, its principles have been established primarily through forward numerical modeling, originally shallow-marine systems more recently nonmarine systems. Predictions these models tested outcrop-scale basin-scale field studies, which also revealed new insights. At multi-basin global scales, joint development biotic records has come largely from macrostratigraphy, analysis gap-bound packages rock. Here, we present recent advances six major areas paleobiology, including critical tests Po Plain Italy, mass extinctions recoveries, contrasts systems, interrelationships habitats architecture, large-scale assembly regional ecosystems. We highlight potential for future research that applies paleobiological concepts studies climate change, geochemistry, phylogenetics, structure conclude with need thinking paleobiology.

Language: Английский

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Bioturbation increases time averaging despite promoting shell disintegration: a test using anthropogenic gradients in sediment accumulation and burrowing on the southern California shelf

Paleobiology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 28

Published: Nov. 7, 2024

Abstract Bioturbation can increase time averaging by downward and upward movements of young old shells within the entire mixed layer accelerating burial into a sequestration zone (SZ), allowing them to bypass uppermost taphonomically active (TAZ). However, bioturbation shell disintegration concurrently, neutralizing positive effects mixing on averaging. Bioirrigation oxygenated pore-water promotes carbonate dissolution in TAZ, biomixing itself mill weakened or microbial maceration, and/or expose damage at sediment–water interface. Here, we fit transition rate matrices bivalve age–frequency distributions from four sediment cores southern California middle shelf (50–75 m) assess competing averaging, exploiting strong gradient rates accumulation created historic wastewater pollution. We find that covaries positively with all sites, accord scenario where ultimately fuels disintegration. Both decline abruptly base 20- 40-cm-thick, age-homogenized surface three well-bioturbated despite different accumulation. In contrast, are very low upper 25 cm an effluent site legacy toxicity, recolonization bioirrigating lucinid bivalves. Assemblages formed during maximum emissions vary strongly millennial scales low-sediment non-effluent centennial scale was high but recovered quickly, decadal second high-sedimentation remained for decades. Thus, even though covary rates, reducing postmortem survival, has net effect increasing skeletal remains this warm-temperate siliciclastic shelf.

Language: Английский

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Dermal denticle assemblages in coral reef sediments correlate with conventional shark surveys

Methods in Ecology and Evolution, Journal Year: 2020, Volume and Issue: 11(3), P. 362 - 375

Published: Jan. 4, 2020

Abstract It is challenging to assess long‐term trends in mobile, long‐lived and relatively rare species such as sharks. Despite ongoing declines many coastal shark populations, conventional surveys might be too fleeting recent describe population over decades millennia. Placing into historical context should improve management efforts well our understanding of past ecosystem dynamics. A new palaeoecological approach for surveying abundance on coral reefs quantify dermal denticle assemblages preserved sediments. This assumes that accumulation rates correlate with abundances. Here, we test this assumption by comparing the record surface sediments three survey methods at Palmyra Atoll, Line Islands, central Pacific Ocean, where density high spatially heterogeneous. We generally found a significant positive correlation between abundances derived from underwater visual census, baited remote video hook line surveys. Denticle reflected abundances, suggesting can preserve signal time‐averaged low‐energy reef environments. offer suggestions applying tool measure long time‐scales other contexts.

Language: Английский

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A downcore increase in time averaging is the null expectation from the transit of death assemblages through a mixed layer

Paleobiology, Journal Year: 2023, Volume and Issue: 49(3), P. 527 - 562

Published: Jan. 19, 2023

Abstract Understanding how time averaging changes during burial is essential for using Holocene and Anthropocene cores to analyze ecosystem change, given the many ways in which affects biodiversity measures. Here, we use transition-rate matrices explore extent of downcore as shells transit through a taphonomically complex mixed layer into permanently buried historical layers: this null model, without any temporal rates sedimentation or bioturbation, contrast with patterns that might be produced by human activity. Assuming stochastic exhumation movements between increments within disintegration increments, find almost all combinations net sedimentation, mixing, produce increase (interquartile range [IQR] shell ages), trend typically associated decrease kurtosis skewness shift from right-skewed symmetrical age distributions. A thus expectation wherever bioturbation generates an internally structured (i.e., surface, well-mixed underlain incompletely layer): under these conditions, are throughout entire at slower rate than they below it sedimentation. This created mixing further amplified decline rate. We accurately reproduce IQR, skewness, observed bivalve assemblages southern California shelf. The age-frequency distributions typical surface death assemblages—the focus most actualistic research—might fossilized exceptional conditions episodic anoxia sudden burial. However, such will not survive subsurface geologically transient. deep-time fossil record dominated instead more time-averaged weakly skewed form lower parts layer.

Language: Английский

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