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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The quality of the fossil record across higher taxa: compositional fidelity of phyla and classes in benthic marine associations

PeerJ, Journal Year: 2023, Volume and Issue: 11, P. e15574 - e15574

Published: July 11, 2023

Although the fossil record preserves a wealth of historical data about past ecosystems, current paradigm, which postulates that fossils provide faithful archives ecological information, stems from research primarily focused on single group organisms known for their high fossilization potential: molluscs. Here, we quantify fidelity higher taxa (six phyla and 11 classes) by comparing live communities sympatric dead remains (death assemblages) using comprehensive surveys benthic marine invertebrates coastal habitats in North Carolina (U.S.A). We found although community composition differed between two assemblages across classes, these differences were predictable with an overabundance robust more preservable groups. In addition, molluscs appear to be excellent proxy all when tracking spatio-temporal patterns shifts structure variety metrics, including measures α , γ β diversity/evenness. This suggests despite filters imposed differential preservation time-averaging, is likely reliable respect relative comparisons diversity shallow paleocommunities. consistent previous work indicating death can yield estimates adequate assessing variability ecosystems existed under natural, pre-anthropogenic conditions.

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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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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Calcium-rich seawater affects the mechanical properties of echinoderm skeleton

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Aug. 28, 2024

Abstract Shifts in the magnesium to calcium ratio of seawater geological history are thought have profoundly affected biomineralization marine invertebrates, including some echinoderms, which changed their skeletal mineralogy from high-magnesium low-magnesium calcite and vice versa. Here we report on experiments that aimed investigate effect ambient nanomechanical properties spines two echinoid species ( Arbacia lixula Paracentrotus lividus ). We found echinoids cultured with a low produced skeleton lower both content nanohardness than those control specimens incubated under normal (high) conditions. These results may suggest at certain times past (during so-called seas) sea urchins decreased contents were more susceptible damage due physical disturbances, predation post-mortem taphonomic processes. Increased hardness aragonite seas is expected enhance potential, thus, extent, mitigates preservation bias related increased solubility calcite.

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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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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Marine conservation palaeobiology: What does the late Quaternary fossil record tell us about modern-day extinctions and biodiversity threats?

Cambridge Prisms Extinction, Journal Year: 2023, Volume and Issue: 1

Published: Jan. 1, 2023

Near-time conservation palaeobiology uses palaeontological, archaeological and other geohistorical records to study the late Quaternary transition of biosphere from its pristine past present-day, human-altered state. Given scarcity data on recent extinctions in oceans, are critical for documenting human-driven extinction threats marine realm. The historical perspective can provide two key insights. First, archive state pre-industrial oceans at local, regional global scales, thus enabling detection extirpations as well shifts species distribution, abundance, body size ecosystem function. Second, we untangle contributions natural anthropogenic processes by centennial-to-millennial changes composition diversity ecosystems before after onset major human impacts. This long-term identifies recently emerging patterns that unprecedented, allowing us better assess biodiversity. Although global-scale not documented brackish invertebrates, studies point numerous extirpations, declines functions, increases range fragmentation dwindling abundance previously widespread species, indicating accumulating a debt.

Language: Английский

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Addressing challenges in marine conservation with fish otoliths and their death assemblages

Geological Society London Special Publications, Journal Year: 2023, Volume and Issue: 529(1), P. 243 - 262

Published: Feb. 16, 2023

Abstract Otolith death assemblages provide a valuable source of biological and ecological information that can help address three main problems in marine conservation: (a) the lack pre-industrial, pre-human-impact baselines for evaluating change; (b) inefficiency survey methods recording small cryptic fish species; (c) absence long-term data on environmental change impacts ecosystems fishes. We review here current knowledge formation preservation otoliths their assemblages, to obtain, date analyse them order detect changes species traits ecology, population structure palaeoceanographic shifts drove them.

Language: Английский

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