Recovery Of Marine Ecosystems Research Articles

Lower to Middle Triassic conodont biostratigraphy and carbonate carbon isotope chemostratigraphy of the Zuodeng area, Guangxi, South China, and its relevance for stratigraphic correlation from the Induan to the Anisian

The Nanpanjiang Basin in South China is a vital area for studying the Early Triassic marine ecosystem recovery in the aftermath of the end-Permian mass extinction (EPME). The Zuodeng sections (A, B, and C) are located on the Debao platform, one of the isolated shallow-water platforms within the Nanpanjiang Basin. This area preserves a relatively complete conodont succession from the Lower Triassic to the lower Middle Triassic. Here, a total of 12 conodont zones and 4 subzones are established, namely, the Hindeodus postparvus Zone, the Hindeodus sosioensis Zone, the Neoclarkina krystyni Zone, the Neoclarkina discreta Zone, the Neospathodus dieneri Zone (including the Neospathodus dieneri M1 and Neospathodus dieneri M3 subzones), the Neospathodus cristagalli Zone, the Neospathodus pakistanensis Zone, the Novispathodus waageni eowaageni Subzone, the Novispathodus waageni waageni Subzone, the Neospathodus yangtzeensis-Novispathodus shani Zone, the Novispathodus pingdingshanensis Zone, the Triassospathodus homeri Zone, the Neospathodus triangularis Zone and the Chiosella timorensis Zone.The Permian-Triassic boundary is placed at the base of Bed 48 in the Zuodeng A section, coinciding with the base of the widespread microbialite beds and the carbon isotope excursion. The Induan-Olenekian boundary is placed at the bases of Bed 86 and Bed 21 in the Zuodeng A and Zuodeng B sections, respectively, where Nv. ex gr. waageni occurs at or slightly below the peak of the positive δ13Ccarb excursion. The Smithian-Spathian boundary is recognized at the bases of Bed 92 and Bed 33 in the Zuodeng A and Zuodeng B sections, respectively, based on the first occurrence (FO) of Nv. pingdingshanensis near the middle point of the positive δ13Ccarb excursion. The Olenekian-Anisian boundary is drawn at the top of Bed 5 in the Zuodeng C section based on the FO of Ch. timorensis. The conodont zones recognized in the Zuodeng area correlate well with sections in South China and elsewhere worldwide. The Ns. yangtzeensis-Nv. shani Zone is newly established, and the recognition of this zone in several sections significantly improves the accuracy of stratigraphic subdivision and correlation of the Smithian. The conodont zones in the Zuodeng area thus provide a high-precision time scale for future studies on marine ecosystem recovery in the aftermath of the EPME and environmental events during the Early Triassic.

Prolonged and gradual recovery of metazoan-algal reefs following the end-Permian mass extinction

The tempo of biotic recovery following extinction reflects the time scales of evolutionary processes and the long-term consequences of degraded ecosystems, but recovery patterns are poorly resolved. In this study, we investigated the tempo of biotic recovery by evaluating metazoan-algal reef assembly following the end-Permian mass extinction. We combined satellite imagery analysis, field mapping, biostratigraphy, and quantitative petrography to assess recovery in the oldest-known and most stratigraphically extensive Lower to Middle Triassic platform-margin reef. The reef occurs in upper Spathian (upper Lower Triassic) to upper Anisian (lower Middle Triassic) strata of the Great Bank of Guizhou (GBG) isolated carbonate platform in south China. Previous work suggests that metazoan-algal reefs were absent for 8−10 m.y. following extinction but were biologically diverse from their Pelsonian (middle Anisian) initiation. This pattern implies that reefs can reassemble rapidly (<< 1 m.y.) when environmental conditions are favorable. In contrast, our analyses indicate that calcareous sponges, calcareous algae, and early scleractinian corals occurred progressively in the GBG reef and that biotic recovery metrics increased gradually. Unlike nonreef ecosystems, biodiverse metazoan-algal reefs were delayed until the late Pelsonian or early Illyrian, postdating broader marine ecosystem recovery and isotopic evidence for carbon-cycle stabilization by 2−4 m.y. Our findings suggest that reef and nonreef ecosystems differ in their recovery pattern and tempo. Reef recovery from severe environmental perturbation can require several million years, even after hospitable conditions return, highlighting the importance of modern reef conservation.

Post-Tsunami monitoring of the introduced Banggai cardinalfish (Pterapogon kauderni) population in Palu Bay

Post-disaster recovery of marine ecosystems and species is still poorly understood. The Banggai cardinalfish (Pterapogon kauderni) is an ornamental fish endemic to the Banggai Archipelago and a few nearby islands. Classified as Endangered in the IUCN Red List, this fish has limited protected status under Indonesian law. Introduced to several sites in Palu Bay in the early 2000’s, two populations had become established by 2006. Until the triple disaster (earthquake, tsunami, liquefaction) in September 2018, these populations were used for research and education as well as the aquarium trade. The tsunami devastated habitat and microhabitat at the Mamboro site; a census in 2019 found 10 surviving juvenile Banggai cardinalfish in one sea anemone. Monitoring in June 2021 revealed signs of ecosystem recovery, especially seagrass. Despite limited microhabitat with few corals and a lack of Diadema sea urchins, there was a substantial increase in Banggai cardinalfish abundance with all life stages present. New recruits were observed in sea anemones and upside-down jellyfish (Cassiopea sp.). These sites present a natural laboratory for P. kauderni population and post-tsunami ecosystem recovery. Lessons learned can be used to inform conservation management of depleted P. kauderni populations in the endemic range of this endangered fish.

Recovery from persistent nutrient-N limitation following the Permian–Triassic mass extinction

Global warming, widespread oceanic anoxia and stagnation, and large perturbations of the global carbon cycle characterized the end-Permian to Middle Triassic interval. Nitrogen isotopes of marine sediments (δ15Nbulk) decreased through the Permian–Triassic transition, implying development of nitrate-limited and ammonium-dominated conditions (i.e., anaerobic marine N cycle) in Early Triassic oceans, which may have contributed to the delay in marine biotic recovery following the end-Permian mass extinction. However, the temporal evolution of the nitrogen cycle and the role of nutrient supply in marine ecosystem recovery during this interval remain poorly understand. Here, we present a new high-resolution Permian–Triassic nitrogen isotope curve from the Nanpanjiang Basin of South China. Low δ15N (−2‰ to +2‰) during the Griesbachian-to-Smithian substages (i.e., first ∼2 Myr of Early Triassic) reflects enhanced nitrogen fixation concurrently with climatic hyperwarming and expansion of oceanic anoxia. A large rise in δ15N (to +8‰) followed by a decline (to −2‰) reflects an aborted recovery of the marine N cycle during the Spathian substage of the Early Triassic. During the Middle Triassic, δ15N fluctuations between +1‰ and +4‰ during the Anisian Stage, followed by stabilization around +4‰ in the Ladinian Stage, suggest a slow stepwise re-establishment of the aerobic marine N cycle. Although both South China and northwestern Pangea experienced a transition to anaerobic N cycling during the Early Triassic, South China experienced an earlier and more rapid onset of this event as well as larger N-cycle fluctuations during the recovery interval than northwestern Pangea. Overall, N cycle changes coincided with those in paleotemperature and ocean-redox state, demonstrating an integrated response of the marine system to the extreme environmental perturbations of the Early Triassic. In summary, our results support persistence of nutrient-N-limited conditions and strong microbial N-fixation throughout the Early Triassic, with a full return to the aerobic N cycle only after stabilization of oceanic environmental conditions during the Middle Triassic.

A globally distributed durophagous marine reptile clade supports the rapid recovery of pelagic ecosystems after the Permo-Triassic mass extinction

Marine ecosystem recovery after the Permo-Triassic mass extinction (PTME) has been extensively studied in the shallow sea, but little is known about the nature of this process in pelagic ecosystems. Omphalosauridae, an enigmatic clade of open-water durophagous marine reptiles, potentially played an important role in the recovery, but their fragmentary fossils and uncertain phylogenetic position have hindered our understanding of their role in the process. Here we report the large basal ichthyosauriform Sclerocormus from the Early Triassic of China that clearly demonstrates an omphalosaurid affinity, allowing for the synonymy of the recently erected Nasorostra with Omphalosauridae. The skull also reveals the anatomy of the unique feeding apparatus of omphalosaurids, likely an adaptation for feeding on hard-shelled pelagic invertebrates, especially ammonoids. Morphofunctional analysis of jaws shows that omphalosaurids occupy the morphospace of marine turtles. Our discovery adds another piece of evidence for an explosive radiation of marine reptiles into the ocean in the Early Triassic and the rapid recovery of pelagic ecosystems after the PTME.

Ocean negative carbon emissions: A new UN Decade program

Ocean negative carbon emissions: A new UN Decade program

The migration of viscous fish eggs in artificial reefs

Artificial reefs play a key functional role in marine ecosystem recovery and particularly in the rebuilding of fish populations. However, improving the reef design for viscous-egg-spawning fish is very challenging. Viscous eggs must adhere to a substrate to continue the hatching process, i.e., increasing the egg adhesion rate of the reef makes it a better fish spawning habitat. Therefore, the movement characteristics of viscous fish eggs in an artificial reef are a vital issue in marine ecology. In this study, a vertical two-dimensional lattice Boltzmann method was developed to simulate the complex hydraulic field in a reef zone and to predict the movement of fish eggs as affected by the hydrographic environment. A particle image velocimetry experiment on fish egg transportation was carried out to validate the model. These results revealed the effects of different hydrodynamic conditions on the migration of sticky eggs in the reef zone, to promote the sustainable development of fisheries and restore the marine ecology.

Evidence for spatiotemporal shift in demersal fishery management priority areas in the western Mediterranean

Marine protected areas (MPAs) are a promising management tool for the conservation and recovery of marine ecosystems, as well as fishery management. MPAs are generally established as permanent closures but marine systems are dynamic, which has generated debate in favour of more dynamic designs. As a consequence, the identification of priority areas should assess their persistence in space and time. Here, we develop a step-by-step approach to assess the spatiotemporal dynamics of fishery management priority areas using standard fishery-independent survey data. To do so, we fit Bayesian hierarchical spatiotemporal SDM (species distribution model) models to different commercially important demersal species and use the resulting maps to fit different spatial prioritisation configurations. The proposed method is illustrated through a western Mediterranean case study using fishery-independent trawl survey data on six commercially important species collected over 17 years. We use these results to assess the spatiotemporal dynamics of fishery priority areas. We identified two fishery priority area patterns in the study area, each predominant during a different time period of the study, asserting the importance of regularly reassessing MPA designs.

Extensive marine anoxia in the European epicontinental sea during the end-Triassic mass extinction

Warming-induced marine anoxia has been hypothesized as an environmental stressor for the end-Triassic mass extinction (ETME), but links between the spread of marine anoxia and the two phases of extinction are poorly constrained. Here, we report iron speciation and trace metal data from the Bristol Channel Basin and Larne Basin of the NW European epicontinental sea (EES), spanning the Triassic–Jurassic (T–J) transition (~ 202–200 Ma). Results show frequent development of anoxic-ferruginous conditions, interspersed with ephemeral euxinic episodes in the Bristol Channel Basin during the latest Rhaetian, whereas the contemporaneous Larne Basin remained largely oxygenated, suggesting heterogeneous redox conditions between basins. Subsequently, more persistent euxinic conditions prevailed across the T–J boundary in both basins, coinciding precisely with the second phase of the ETME. We propose that this later phase of benthic faunal loss in the NW EES was directly driven by the bottom-water oxygen crisis. Conversely, although anoxic conditions persisted into the early Hettangian, the benthos diversified at this time in nearshore areas. Post-extinction conditions were poised at a fluctuating redox state, but anoxia did not extend into the shallowest areas where benthic marine ecosystem recovery was occurring. • Water column anoxia was common in the European epicontinental sea through the Triassic–Jurassic transition. • Intensified marine euxinia developed at the second phase of the end-Triassic mass extinction. • A low oxygen ocean persisted post-extinction, but with a fluctuating redox state and limited ecological influence.

Blue economy: Concept research and review of the European Union

The concept of the blue economy is a part of a new wave of economic thought that emphasizes the sustainable use of natural resources in the world?s oceans, seas and coastal areas. The blue economy, which is dominated by the principle of sustainability, is directly contrasted with the development of another cycle of linear exploitation of limited planetary resources. In contrast, a sustainable blue economy envisages economic activities such as greening shipping, coastal renewable energy, carbon sequestration, eco-tourism, genetic marine resources, sustainable aquaculture and the development of new seafood as new trends in the decades ahead. The paper analyzes the key postulates of the blue economy concept, as well as European experiences and challenges in this field, using the methods of theoretical analysis. Based on the empirical findings of the paper, the general conclusion is that the oceans, coastal areas and marine activities will play a crucial role for the economic and environmental future of the European Union and its citizens. The European blue economy can and must be a central and solid pillar that contributes to the general resilience of society itself. Overall, the European Union has recognized the importance of the blue economy in generating new jobs and achieving prosperity and security, but its potential has yet to be unlocked. What is important is that the affirmation of the concept of the blue economy takes place in the spirit of the fundamental principles of the 2020 strategy, according to which growth must be smart (with respect to integration of cutting edge science-based, innovative solutions and industrial leadership), sustainable (in economic, social and ecological terms tackling societal challenges) and inclusive (considering the multitude of coastal, marine and maritime activities and trade-offs between them). The general lesson is that the European institutions responsible for ocean health and safety must seriously consider an appropriate framework that allows the blue economy to thrive while maintaining high standards of sustainable development in line with the EU?s vision for a carbon-free society. When it comes to the European Union (and its members), the development of the sustainable and fair blue economy in the coming period should take place in accordance with the principles of the European Green Agreement, as a long-term strategy for sustainable growth, which will require: transformation of value chains of the blue economy in terms of moving away from linear business models to circular ones, with less resource consumption and waste; introduction of stricter measures against marine pollution, coastal waste and plastics; fossil fuel replacement; investing in biodiversity conservation; restoration and protection of ecosystems; promoting nature-based solutions and options and incubating marine renewable energy and innovative blue biotechnology. At the same time, all blue economy sectors have to reduce their climate and environmental impact and contribute to the recovery of marine ecosystems. In achieving overarching goals such as reducing greenhouse gas emissions, increasing resource efficiency and reducing overall environmental impact, the EU should focus on five promising and innovative sectors, namely: blue energy, aquaculture, coastal and maritime 256 tourism, blue biotechnology and seabed mining. To address the previous challenges, special emphasis should be placed on the need for multisectoral, inclusive, transparent and holistic governance (public-private dialogue) to integrate the sustainable use of human resources with environmental protection and social justice. Improving governance processes should primarily be based on: 1. Citizen engagement and ocean literacy, namely, the involvement and empowerment of local communities and 2. ?ffirmation of maritime spatial planning, with the following advantages: protect the environment through early identification of impact and opportunities for multiple use of space; encourage investment by creating predictability, transparency and clearer rules; increase cross-border cooperation between EU countries to develop energy grids, shipping lanes, pipelines, submarine cables and other activities, but also to develop coherent networks of protected areas; and reduce conflicts between sectors and create synergies between different activities.

Mercury stable isotopes constrain atmospheric sources to the ocean.

Human exposure to toxic mercury (Hg) is dominated by the consumption of seafood1,2. Earth system models suggest that Hg in marine ecosystems is supplied by atmospheric wet and dry Hg(II) deposition, with a three times smaller contribution from gaseous Hg(0) uptake3,4. Observations of marine Hg(II) deposition and Hg(0) gas exchange are sparse, however5, leaving the suggested importance of Hg(II) deposition6 ill-constrained. Here we present the first Hg stable isotope measurements of total Hg (tHg) in surface and deep Atlantic and Mediterranean seawater and use them to quantify atmospheric Hg deposition pathways. We observe overall similar tHg isotope compositions, with median Δ200Hg signatures of 0.02‰, lying in between atmospheric Hg(0) and Hg(II) deposition end-members. We use a Δ200Hg isotope mass balance to estimate that seawater tHg can be explained by the mixing of 42% (median; interquartile range,24-50%) atmospheric Hg(II) gross deposition and 58% (50-76%) Hg(0) gross uptake. We measure and compile additional, global marine Hg isotope data including particulate Hg, sediments and biota and observe a latitudinal Δ200Hg gradient that indicates larger ocean Hg(0) uptake at high latitudes. Our findings suggest that global atmospheric Hg(0) uptake by the oceans is equal to Hg(II) deposition, which has implications for our understanding of atmospheric Hg dispersal and marine ecosystem recovery.

Environmental changes in the Middle Triassic lacustrine basin (Ordos, North China): Implication for biotic recovery of freshwater ecosystem following the Permian-Triassic mass extinction

Increasing evidence shows that the recovery of marine ecosystems after the Permian/Triassic mass extinction (PTME) was coupled with environmental amelioration. Recently, abundant insects and complete trophic structures were unraveled from the Ladinian (late Middle Triassic) in the Ordos basin, central China, deciphering recovery of lacustrine ecosystem from the PTME. Coeval environmental settings, however, remain unclear. In the Ordos basin, the Ladinian succession is dominated by black organic-matter-rich shales of the Chang 7 Member of the Yanchang Formation, and their depositional environments and palaeo-productivity are reconstructed based on major and trace element concentrations, pyrite framboid size and morphology, and total organic carbon (TOC) contents. High values of TOC and phosphorous (P) concentrations, as well as more enrichment of trace-metal elements such as Copper (Cu) and zinc (Zn) all indicate a rather high primary productivity. Such a high productivity during the deposition of the Chang 7 3 sub-member is also reinforced by and the presence of abundant organic-matter-enrich laminae in black shales and the diverse chrysophytes, as well as intensive occurrence of tuff layers and possible hydrothermal fluids. Analyses of framboidal pyrite size and morphology as well as C org /P ratio and trace-metal elements such as molybdenum (Mo) and uranium (U), indicate the dysoxic to oxic conditions in water columns of the Ordos lake during the late Middle Triassic. The Ladinian-Carnian cooling likely promoted the occurrence of dissolved oxygens in the lake. As a result, although the massive black shales of the Chang 7 3 sub-member were deposited and suggest a rather high primary productivity, they also indicate slightly oxygen-poor to oxygenated conditions of water columns, which are inductive for lacustrine biota to inhabit, and also offer hospitable habitats for freshwater lake ecosystems to recover from the PTME. • A rather high primary productivity occurred in a Ladinian freshwater lake. • Slightly oxygen-poor to oxygenated water conditions developed in a Ladinian lake. • Ordos lake offered hospitable habitats for freshwater ecosystems to recover.

Quantifying deep-water marine ecospace utilization andecosystem engineering from late Permian to Middle Triassic

<p indent=0mm>With the loss of around three-fourths of marine and continental genera, the end-Permian mass extinction (EPME) event was the biggest biotic crisis in the Phanerozoic era. The shallow marine and continental ecosystem were almost collapsed due to continuous harsh and turbulent environment, e.g., global warming and anoxic event. However, the overall response strategies of biotic communities and function of marine ecosystem engineering are still uncertain. As a promising window for understanding organism-environmental interactions, trace fossils not only record the response of soft-bodied animals that are not easily preserved as fossils to the mass extinction event, but also record a large number of complex behaviors involving the construction of ecosystems, and document the entire process of the collapse and recovery of marine ecosystems during the Permian-Triassic transition. A global Permian-Triassic deep-water marine database was compiled on the basis of literatures and personal data. The total number of invertebrate ichnogenera identified as valid is 62 from a survey of 146 Permian-Triassic stratigraphic unites. Ichnodiversity simply refers to the number of ichnotaxa present at ichnogenus level. Ichnodisparity is a measure of the variability of morphological plans in trace fossils, which reveals major innovations in body plan, locomotive system, and behavioral program. The multidimensional ecospace utilization and ecosystem engineering schemes based on body fossils have been adapted for trace fossils. Ecospace utilization is quantified on the basis of the number of modes of life, following three parameters: Tiering (subdivided into surficial, semi-infaunal, shallow, intermediate and deep tiers), motility (subdivided into motile, facultatively motile and non-motile types), and feeding mode (subdivided into suspension feeding, non-specialized deposit feeding, specialized deposit feeding, predation and others). Ecosystem engineering is categorized on the basis of three parameters: Tiering (as described above), mode of sediment interaction (intrusion, compression, backfilling and excavation), and mode of sediment modification (biodiffusion, conveyors, regenerators, and gallery biodiffusion). Ecosystem engineering impact (EEI) values and ranges on the basis of three parameters: (1) Tiering (surficial tier, semi-infaunal tier, shallow tier, intermediate tier, and deep tier); (2) bioirrigation potential (improbable, probable, and possible); and (3) potential functional group, describing how substrate is modified by burrowing organisms (biodiffusion, conveyors, regenerators, and gallery biodiffusion). This paper aims to understand the patterns of EPME on the marine deep-water ecospace utilization and ecosystem engineering, and the adaptation and modification mechanism of organisms in the Early Triassic deep-water ecosystem recovery from an ecological perspective. Our results show that in the Permian-Triassic transition, ichnodiversity, ichnodisparity, bioturbation index, the ecospace utilization and ecosystem engineering cubes of deep-water marine were not significantly declined, indicating that the marine deep-water ecosystem was under relatively stable conditions during the EPME. Non-specialized deposit feeding, motile, gallery biodiffusion and compression were the most common ecosystem engineers. Notably, gallery biodiffusion, as the highest impact sediment modification functional group, is present through the transition of Permian-Triassic. Modes of life in the Early and Middle Triassic tend to be diversified and dominated by the backfilling-conveyors in the shallow tiering. Increased bioirrigation further affected the geochemical cycle of the substrate in the Early Triassic and laid the foundation the further construction and development of deep tiering ecospace utilization. In the Middle Triassic, the nutrient deep-tiering ecospace was inhabited by organisms with advanced bioirrigation capacities.

Astronomically forced changes in chemical weathering and redox during the Anisian (Middle Triassic): Implications for marine ecosystem recovery following the end-Permian mass extinction

The timing and pattern of ecosystem recovery following the end-Permian mass extinction are still highly controversial, and a potential influence from orbital climate forcing is often not considered. To investigate this issue, a cyclostratigraphic analysis of an Anisian (Middle Triassic) marine platform succession (Guanling Formation, Yongning section, South China) using elemental proxies and lithofacies has been carried out. Spectral analysis of proxies for terrestrial flux (Fe/Al and Zr/Al) indicate significant cycles. Based on available age constraints and sedimentation rate modelling, the recognized cycles include 405-kyr long eccentricity, 100-kyr short eccentricity and ~ 20-kyr precession cycles. Anchoring these signals to a dated and widespread “green bean” volcanic ash layer (246.6 Ma) and tuning to stable 405-kyr long-eccentricity cycles yields an astronomical time scale spanning ~4.2 + 0.3/−1.4 Myr (246.7 to 242.5 + 0.3/−1.4 Ma) in the Anisian. This time scale constrains the ages of the Luoping biota (which marks the earliest complex Mesozoic marine ecosystem in South China) and the Panxian marine vertebrate biota to 243.8 + 0.3/−1.4 and 243.4 + 0.3/−1.4 Ma, respectively. The early Anisian is characterized by intercalated claystone and marls with high values in terrestrial flux proxies, indicating an intensified hydrological cycle due to a humid climate in the study area. This was followed by a long-term cooling trend into the late Anisian, as indicated by declining terrestrial flux proxy values. Seawater redox conditions were assessed using V/Al, Mo/Al and lithofacies analyses, and these data reveal possibly two putative deoxygenation events during the Anisian. Our new high-resolution redox data can also be correlated with results on Anisian ocean redox changes elsewhere. Our new astronomical timescale and high-resolution geochemical data provide key constraints on the timing of marine ecosystem recovery after the end-Permian mass extinction. Orbital forcing seems to have played an important role in modulating chemical weathering and seawater chemistry dynamics that impacted the timing of ecosystem recovery.

Early Anisian (Middle Triassic) Conodonts from Romania and China, with Comments on Their Role in the Recognition and Correlation of the Base of the Anisian

The Olenekian-Anisian Boundary (OAB) interval is an important time in Earth history, reflecting the last phase of marine ecosystem recovery in the aftermath of the end-Permian mass extinction. Despite this, the Global Stratotype Section and Point (GSSP) for the base of the Anisian remains undefined. The first appearance of the conodont Chiosella timorensis has been proposed as a potential index for the boundary; however, the discovery of this conodont with ammonoids traditionally considered to be Spathian has generated doubts about its suitability. The taxonomy and relationships of early Anisian conodonts, including species of Chiosella, remain understudied, which leads to difficulties in correlation. New species of Neogondolella (N. gradinarui) and Magnigondolella (M. n. sp. D) have been recognized from the leading GSSP candidate section for the OAB at Desli Caira, and from an additional OAB section at Guandao. Furthermore, several species previously identified in Canada and the USA can be recognized from these sections, improving correlation between Tethys and North America. One of these species may serve as a suitable alternative proxy for the OAB; for instance, N. curva appears just below the first Anisian ammonoids in Desli Caira, and just above the first appearance of C. timorensis in both Desli Caira and Guandao. Continued work on sections other than the candidate sections, and on the taxonomy of species outside of those traditionally proposed as indices, is required.

The link between exceptional fossil preservation and palaeo‐redox conditions in the Middle Triassic Luoping Biota from South China

The Luoping Biota represents of the recovery of marine ecosystems after the Permian–Triassic Mass Extinction. To better understand the palaeoenvironmental background of the Luoping Biota, sedimentary analysis and multi‐geochemical proxies (Mo, U, V, V/Cr, MoEF, UEF, and VEF) were assessed in Member II of the Middle Triassic Guanling Formation of the Xiangdongpo section in Luoping County, Yunnan Province. According to the facies characteristics and redox‐sensitive elemental proxies, in combination with macrofossil and bioturbation evidence, five intervals (I, II, III, IV, and V) were recognized. The exceptional preservation of the fossils is related to two anoxic intervals (II and IV) sandwiched by three suboxic intervals (I, III, and V). Based on this study and regional correlation, it is concluded that anoxia in the water‐column increased the preservation potential of macrofauna fossils and inhibited the survival of trace‐making organisms. In addition, microbial mats could produce local anoxic and restricted micro‐environments, preventing the disarticulation of the carcasses by water turbulence. Therefore, we demonstrate that anoxic conditions played a key role in the exceptional fossil preservation of the Luoping Biota.

The long and narrow path for novel cell‐based seafood to reduce fishing pressure for marine ecosystem recovery

AbstractCell‐based seafood is an emerging novel food, with many start‐up companies aspiring for ocean conservation benefits through expanded market share that displaces wild‐caught seafood. However, the ability for cell‐based seafood to achieve this conservation outcome is often oversimplified and will rely on an extensive, and we find somewhat tenuous, chain of events. Here, we outline the technological, behavioural, market and ecological changes that must occur along this pathway, and conclude that fisheries recoveries and collateral ocean benefits are unlikely to result from cell‐based seafood technology. In particular, we detail nine necessary steps and argue that failure at any one step could hinder or even eliminate cell‐based seafood's conservation effects. We additionally draw comparisons to aquaculture and share broader lessons for other demand‐driven product interventions.

Changes in productivity associated with algal-microbial shifts during the Early Triassic recovery of marine ecosystems

Abstract The recovery of marine ecosystems in the aftermath of the Permian-Triassic mass extinction was accompanied by significant carbon-cycle perturbations, as reflected in large-amplitude global excursions in Lower Triassic carbonate carbon isotope records. In the present study, we generated paired carbonate carbon (δ13Ccarb), organic carbon (δ13Corg), and nitrogen (δ15N) isotope records along with molar C/N ratios for a composite section in the Chaohu area of Anhui Province (northern Yangtze Platform, South China) that spans the entire Lower Triassic. These records document concurrent changes among multiple proxies related to marine plankton community composition, productivity rates, and nutricline structure, providing unparalleled insights into changes at the base of the marine trophic web during the Early Triassic recovery interval. Changes in carbonate-organic carbon isotopic differences (Δ13Ccarb-org) and C/N ratios indicate a general shift from anoxygenic photoautotrophy to eukaryotic algal productivity during the Early Triassic. The prevalence of prokaryotic photoautotrophs in the Griesbachian to Smithian was due to frequent environmental disturbance, whereas the reestablishment of eukaryotic algae as dominant primary producers in the Spathian reflects a general amelioration of marine environments at that time. Positive δ13Ccarb excursions and brief spikes toward higher Δ13Ccarb-org and C/N ratios around the Induan-Olenekian boundary and Smithian-Spathian boundary record transient shifts toward improved conditions and temporary rebounds of algal productivity. A negative δ15N shift was associated with decreasing δ13Ccarb, indicating that marine productivity was closely linked to N-fixation intensity owing to a general nutrient-N deficiency. Synchronous fluctuations of δ13Ccarb and δ13Corg through the Olenekian reflect changes in the δ13C of oceanic dissolved inorganic carbon, but the more limited variation in δ13Corg may have been due to concurrent changes in algal-microbial assemblages and, thus, net photosynthetic fractionation of carbon isotopes.

Intensified chemical weathering during Early Triassic revealed by magnesium isotopes

Marine ecosystem recovery after the latest Permian mass extinction (LPME) was a protracted process during the Early Triassic (∼252–247 Ma) owing to repeated climatic and environmental perturbations. Chemical weathering can supply nutrients to the ocean and may have played an important role in the Early Triassic carbon cycle and biological recovery. However, only limited geochemical records of chemical weathering during the Early Triassic have been presented to date, and the relationship between changes in weathering intensity and the slow recovery of marine ecosystems is effectively unknown. Here, we report magnesium (Mg) isotopic compositions of the siliciclastic components from shallow-marine carbonates in two well-studied Upper Permian-Lower Triassic sections in Iran and South China to track changes in chemical weathering intensity after the LPME. Both sections display a wide range of δ26Mg values (−2.09‰ to +1.10‰ at Zal, −2.30‰ to +0.33‰ at Zuodeng). We identified two distinct stages (I and II) in each section based on δ26Mg values and major elemental ratios. Variations of δ26Mg values in Stage I (Changhsingian to mid-Dienerian) are mainly controlled by mineralogical composition that can obscure weathering signals. By contrast, δ26Mg variations in Stage II (upper Dienerian to upper Spathian) are independent of lithology and inferred to reflect control by chemical weathering intensity. The trends in chemical weathering intensity within Stage II correspond to first-order variations in climate and carbon cycling. Marine ecosystem recovery during the Early Triassic may have been linked to recurrent episodes of intense chemical weathering caused by CO2 degassing and climate warming. This study demonstrates the potential utility of the Mg isotopic compositions of the silicate fraction in marine carbonates as a proxy for chemical weathering intensity, laying the groundwork for general applications of this method to deep-time Earth systems.

Governance strategies for a successful marine protected area – The case of Torre Guaceto

Marine protected areas (MPAs) are an essential tool for the protection and recovery of marine ecosystems. Most Mediterranean MPAs are multiple-use, i.e., they include a small no-take area and a buffer zone where extractive and non-extractive economic activities are allowed, mostly under restricted conditions. Multiple-use MPAs are characterised by specific governance challenges, which differ from those of no-take ones. They need to find a compromise between conservation goals and the interests of different categories of stakeholders, and in particular the fishery and tourism sectors – whose support and buy-in are essential to ensure compliance. For this reason, it is important to analyse the governance strategy of multiple-use MPAs that are successful both from an environmental and a socio-economic point of view. To contribute to this debate I herein explore the governance strategy of the Torre Guaceto MPA in south-east Italy, a success story that shows how, even in a difficult socio-economic context and with limited public funding, a MPA can lead to the recovery of ecosystems while providing economic benefits to the tourism and fishery sectors. Drawing from a focus group with fishermen and in-depth semi-structured interviews with key stakeholders from the managing Consortium, the tourist and agriculture sectors and two local residents, I argue that the reason for the success of the Torre Guaceto MPA can be found in the use of multiple economic and non-economic incentives, which catalyse synergies among sectors, and in the strong leadership by two local, well-respected, committed and pro-active leaders.