Realistic scenarios of environmental disturbance lead to functionally important changes in benthic species-environment interactions

Marine Environmental Research, Journal Year: 2019, Volume and Issue: 150, P. 104770 - 104770

Published: Aug. 7, 2019

Changes in community structure concurrent with environmental forcing often form a precursor to changes species diversity, and can have substantive consequences for ecosystem functioning. Here, we assess the effects of altered levels evenness that are representative different eutrophication salinity associated precipitation patterns, on mediation nutrient release by sediment-dwelling invertebrate communities. We find an adjustment towards more even distribution corresponds increase sediment particle reworking that, general, translates increased release. This response, however, is dependent functional role each influenced concomitant salinity, especially when extends beyond range typically experienced community. Overall, our findings highlight dynamic nature contributions functioning reinforce importance understanding when, how, mechanistic basis species-environment interactions modified as influence abiotic biotic factors flex under periods directional forcing.

Language: Английский

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MOLLUSCAN LIVE-DEAD FIDELITY OF A STORM-DOMINATED SHALLOW-MARINE SETTING AND ITS IMPLICATIONS

Palaios, Journal Year: 2021, Volume and Issue: 36(2), P. 77 - 93

Published: Feb. 28, 2021

ABSTRACT Actualistic studies are important for evaluating the fidelity of fossil assemblages in representing living community. Poor live-dead (LD) molluscan may result from transport-induced mixing. Large-scale mixing is more common siliciclastic settings with a narrow shelf, high sedimentation rate, and those that frequented by episodically high-energy events. Chandipur-on-sea, on east coast India has an optimal setting to promote such conditions. By studying LD modeling size-frequency distribution (SFD) fauna, we attempted evaluate contribution “out-of-habitat” versus “within-habitat” developing death assemblage. The correlation between composition live (LA) (DA) was insufficient; unlike LAs, DAs do not show environmental partitioning ordination space. A numerical simulation shell size frequency LAs compared observed SFD DAs. results this indicate likely be product within-habitat probably received considerable input via regional transport, facilitated frequent tropical cyclones affecting Odisha. Chandipur receives large proportion originating above 15°N, which causes degree lateral transport 15° 21°N, explained compositional similarity species within latitudinal extent. Our study highlights significance out-of-habitat shaping marine assemblages, especially storm dominated shallow-marine settings.

Language: Английский

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Basin-wide infaunalisation of benthic soft-bottom communities driven by anthropogenic habitat degradation in the northern Adriatic Sea

Marine Ecology Progress Series, Journal Year: 2021, Volume and Issue: 671, P. 45 - 65

Published: June 2, 2021

Shallow coastal seas play an important role in the economy of many countries by sustaining fisheries, tourism, aquaculture and other economic activities. Their exploitation has large-scale ecosystem effects that are easily overlooked, as they often built up over decades or centuries, historical ecological reference data rarely available. Here, we assess these comparing live surface death assemblages (recording community states) soft-bottom molluscs across a range habitats northern Adriatic Sea, using degree mismatch between 2 proxy for change. We found consistent live-dead at all stations. Although varied stations with low high time-averaging (i.e. post-mortem shell ages), change followed same trend entire basin regardless type sedimentary environment, loss epifaunal species reduction grazers, carnivores, herbivores. In turn, abundance infaunal opportunistic feeding on plankton detritus strongly increased living communities. Directionality magnitude changes cannot be explained differences durability, but reflect true shift response to multiple, long-lasting anthropogenic pressures, mainly bottom trawling, eutrophication hypoxia. The original heterogeneous characteristic different thus replaced more infaunal, functionally impoverished less diverse benthic representing new baseline shaped human impact.

Language: Английский

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Marine bioturbation collapse during Early Jurassic deoxygenation: implications for post-extinction marine ecosystem functioning

Geological Society London Special Publications, Journal Year: 2023, Volume and Issue: 529(1), P. 311 - 344

Published: Jan. 9, 2023

Abstract Climate change is undermining the health and integrity of seafloor ecosystems, with declines in bioturbation expected to impact future ecosystem functioning. We explored changes nature degree during Early Jurassic global warming ocean deoxygenation. Understanding how these communities responded can help anticipate functioning might over large spatial temporal scales. Trace body fossils from outcrop core Cleveland Basin, UK show healthy deteriorated through Pliensbachian spinatum Zone, macroinfaunal behaviour fluctuated across Pliensbachian–Toarcian boundary coincident mass extinction. Deoxygenation began above stage boundary, conditions until ceased completely (upper tenuicostatum Zone) for 0.6–2.5 Ma, longer than anywhere else NW Tethys. The record revealed new details on progression timing deoxygenation, benthic recovery fluctuations palaeoredox boundary. After oceanic anoxic event infauna were fewer, smaller did not mix sediments depth, while depth diversity had increased by fibulatum Subzone ( bifrons Zone), benthos recovered late pre-oceanic state. Bioturbation collapse parts Northern Hemisphere probably contributed regional-scale

Language: Английский

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Pyrite-lined shells as indicators of inefficient bioirrigation in the Holocene–Anthropocene stratigraphic record

Biogeosciences, Journal Year: 2021, Volume and Issue: 18(22), P. 5929 - 5965

Published: Nov. 22, 2021

Abstract. Although the depth of bioturbation can be estimated on basis ichnofabric, timescale sediment mixing (reworking) and irrigation (ventilation) by burrowers that affects carbonate preservation biogeochemical cycles is difficult to estimate in stratigraphic record. However, pyrite linings interior shells a signature slow shallow irrigation. They indicate molluscs initially inhabiting oxic pockets were immediately permanently sequestered reduced, iron-rich microenvironments within mixed layer. Molluscan biomass-stimulated sulfate reduction precipitation was confined location decay under such conditions. A high abundance pyrite-lined record thus diagnostic limited exposure organic tissues O2 even when seafloor inhabited abundant infauna disrupting age-homogenizing sedimentary fabric as present-day northern Adriatic Sea. Here, we reconstruct this sequestration pathway characterized (1) assessing postmortem ages shallow-infaunal hypoxia-tolerant bivalve Varicorbula gibba cores (2) evaluating whether an independently documented decline mixing, driven frequency seasonal hypoxia during 20th century, affected First, at prodelta sites with sedimentation rate, framboids form rapidly upper 5–10 cm they already appear interiors younger than 10 years occur preferentially well-preserved articulated periostracum. Second, increments deposited early century contain < 20 % lined Po 30 %–40 Isonzo prodelta, whereas late possess 50 %–80 both locations. At low (< %–20 %). Surface sediments remained well deposit detritus feeders maintaining suboxic zone dissolved iron. The upcore increase indicates oxycline reduced bioirrigation rates declined century. We hypothesize permanent V. subsurface enabled recovery infaunal communities from hypoxic events, leading dominance surficial modifiers potential. presence very young valves uppermost zones layer rapid obrution episodic deposition not needed for transient background are (here, exceeding ∼ 0.1 yr−1) organisms die their living position sediment. Abundance per assemblage apparently well-mixed deep-time indicator inefficient bioirrigation. Fine-grained Sea since mid-20th potential formed layer, represent taphonomic diagenetic analogues skeletal assemblages linings.

Language: Английский

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