Ecological Restructuring Research Articles

Ocean oxygenation and ecological restructuring caused by the late Paleozoic evolution of land plants

The dramatic increase in ocean-atmosphere oxygen levels during the Devonian and Mississippian is increasingly linked to the diversification of land plants, yet the timing and extent of this event remain uncertain. This study uses the redox-sensitive rare earth element cerium (cerium anomaly—Ce/Ce*) to investigate ocean redox conditions during the deposition of globally distributed Paleozoic carbonate strata. Our Paleozoic Ce/Ce* record suggests that Cambrian, Ordovician, and Silurian oceans had relatively low O2 levels (mean Ce/Ce* = 0.86 ± 0.10, 0.91 ± 0.14, and 0.91 ± 0.10 [±1σ], respectively). In contrast, short-lived ocean oxygenation events, possibly related to the diversification of small land plants, likely occurred throughout the Early and Middle Devonian (mean Ce/Ce* = 0.80 ± 0.07 and 0.58 ± 0.14, respectively). “Modern” Ce/Ce* values (<0.36) first occurred during the Late Devonian, suggesting that the main phase of Devonian and Mississippian oceanic oxygenation was related to the evolution of large vascular plants and the first forests. Despite this, the significant variability of Ce/Ce* values during this time suggests that shallow marine settings were susceptible to redox instability, possibly caused by upwelling of anoxic deep waters. This redox instability potentially provides evidence of a mechanism for contemporaneous mass extinction and metazoan reef collapse events. Development of strongly oxic conditions during the Late Devonian may have resulted in the demise of many Paleozoic-type organisms, facilitated the radiation of the modern evolutionary fauna, and established the modern oxygenated ocean-atmosphere system.

Recent global warming induces the coupling of dissimilar long-term sedimentary signatures in two adjacent volcanic lakes (Azores Archipelago, Portugal)

Paleoclimatological information derived from the study of lacustrine sedimentary records is not only biased by taphonomical processes but also by potential differences in the expression of climate variability in the sediments due to site-specific factors. Using a multiproxy approach (the elemental and isotopic compositions of organic matter, diatom assemblages, and marker pigments of algae and cyanobacteria), we study the different environmental signatures recorded since the Little Ice Age (LIA) in the sediments of two volcanic lakes located within the same caldera on São Miguel Island (Azores Archipelago). Lake Santiago is a crater lake whose eutrophic status in the last stage of the LIA was linked to external nutrient inputs associated with this humid period. Its post-LIA evolution was forced by changes in the thermal structure of the water, which determined its degree of mixing and therefore nutrient availability through recycling from the hypolimnion. In contrast, the decadal to centennial limnological evolution of Lake Azul, a caldera lake 2.5 km from Lake Santiago, shows geochemical and micropaleontological signatures disconnected from climate variability until 1980/1990 CE due to its greater exposure to the fallout of tephra after a catastrophic eruption in c. 1290 CE. Only after 1980/1990 CE did a global warming scenario induce a common ecological restructuring of both lakes, involving the replacement of turbulence-loving algal taxa by species adapted to strengthening water column stratification. Nevertheless, this shift was relatively gradual in Lake Azul but more sudden in Lake Santiago, indicating that the local site-specific components still had an effect on the expression of climate change in the sediments. Despite the short history of anthropogenic pressure (compared to their continental counterparts) and the large atmospheric patterns operating over the Azores Archipelago, the sedimentary records of these two adjacent oceanic volcanic lakes reacted quite differently to climate changes.

Towards sustainable and regenerative territories: ecological restructuring of phosphorus retention and mobilization based on substance flow analysis (sfa) in Quirino Province

Phosphorus (P) is an essential and finite nutrient element that cannot be substituted by any other substance. To overcome limited supply of mineral Phosphate rocks (PR) deposits and to contribute to its sustainable management, a better knowledge on P flows is needed. In this study, a Substance Flow Analysis (SFA) for P was conducted for the Quirino Province. Different subsystems were investigated such as forestry, agriculture, anthropogenic consumption, organic wastes, and wastewater management. The researcher found that within the system under study, there is an excess total P inflow into the three (3) major river watersheds system in Quirino Province. The aim of the study was to analyze the flow of Phosphorus that enter, transform, pass through, and leave the territorial subsystems in order to create a knowledge bank that will aid in the transition of Quirino Province from linear to circular metabolism.

The Dilemma and Application Construction of Integrated Management of Marine Ecological Environment

Starting from the background of the continuous improvement of the quality of sustainable economic development, this paper analyzes and studies the governance concepts and governance methods in the governance of China’s marine ecological environment. In order to continuously meet higher standards and requirements in the management of the marine ecological environment, we must pay more attention to the process of ecological problem solving mechanisms, and to coordinate excessive decentralization and comprehensive management. This article first briefly describes the importance of improving the effect of marine ecological environment governance, and at the same time analyzes the problems existing in the current stage of China’s marine ecological environment governance restructuring and information sharing work. The author explored strategies to further improve the efficiency and quality of the overall framework of China’s marine ecological environment governance.

Basin-Specific Pollutant Bioaccumulation Patterns Define Lake Huron Forage Fish.

The Lake Huron ecosystem is unique among the Laurentian Great Lakes (USA/Canada) in that its surface area encompasses 3 distinct basins. This ecosystem recently experienced significant ecological restructuring characterized by changes in primary production, species dominance and abundances, and top predator energy dynamics. However, much of the evidence for this restructuring has been largely derived from biomonitoring data obtained from long-term sampling of the lake's Main Basin. We examined polychlorinated biphenyl (PCB) concentrations and the stable isotopes of carbon (δ13 C) and nitrogen (δ15 N) in rainbow smelt (Osmerus mordax), bloater (Coregonus hoyi), and round goby (Neogobius melanostomus) to determine spatial variability in these environmental markers as indicators of the ubiquity of trophic restructuring throughout Lake Huron. Stable isotopes indicated that North Channel fish occupied trophic positions between 0.5 and 1.0 lower relative to Main Basin and Georgian Bay conspecifics, respectively. Sum PCB concentrations for 41 congeners were highest for fish from the Main Basin (27.5 ± 3.0 ng g-1 wet wt) and Georgian Bay (26.3 ± 3.4 ng g-1 wet wt) relative to North Channel (13.6 ± 1.2 ng g-1 wet wt) fish. Discriminant functions analysis demonstrated basin-specific PCB congener profiles with individual species also having distinct profiles dependent on their basin of collection. These bioaccumulation patterns among Lake Huron forage fish mirror those reported for lake trout in this lake and indicate that the degree of food-web ecological restructuring in Lake Huron is not equivalent across the basins. Specifically, basin-specific PCB congener profiles demonstrated that differences among Lake Huron secondary and top predator consumer species are likely dictated by cross-basin differences in zooplankton community ecology and trophodynamics that can regulate the efficiencies of prey energy transfer and PCB congener bioaccumulation patterns in aquatic food webs. Environ Toxicol Chem 2020;39:1712-1723. © 2020 SETAC.

The Features of Floristic Composition and Community Structure of the Birch Forests in the Forest-to-Bog Ecotones in the South of the Vasyugan Plain

The present study addresses the floristic composition and ecological and community structure of paludified birch forests (peat depth reaching 30 cm) in the southern taiga. The growing conditions were evaluated based on the indicator values of plants and soil chemical properties. The study plots were located on transects directed from upland forests through peripheral wetland forests to bogs, which are situated in topographic lows, at the North-East edge of the Great Vasyugan mire. The sites of the forest-to-bog ecotone that are transformed to various degrees by the bog water regime are considered as successive stages of paludification. Because of the high carbonate content of the soil-forming rocks dominated by heavy clay particles and waterlogging by ground-mire waters, wet green forests without a developed moss cover form here on rich peat-humus soils at the initial stages of hydromorphic transformation of the plant community. This is in contrast to typical plant successions, which develop on carbonate-free sediments and whose development is associated with the effect of acid bog waters. Reed grass (Calamagrostis phragmitoides C. Hartman) dominates the ground vegetation, which also includes sedges (Carex canescens L., C. vaginata Tausch., C. disperma Dew.). The high contents of mineral nutrients in organics-accumulating dark humus soils determines the high floristic diversity of paludified birch forests, comparable with the diversity of upland communities. A significant part of the ground cover of these forests (25% of the species composition, up to 50% of the projective cover) is represented by nutrient-demanding forest- and meadow-swamp plant species, which commonly occur in eutrophic boreal forested swamps of West Siberia with groundwater input. These species are absent in the mesotrophic paludified taiga forests. At a later stage of hydromorphic transformation, pine-birch shrub-moss forests form on peat-humus-gley and peat-gley soils. As the nutrient availability of soils declines, the number of plant species decreases, and plant species with lower nutrient requirements begin to predominate. This leads to the ecological restructuring of wet communities and makes them similar to paludified forests on carbonate-free sediments; peat accumulation begins with the deposition of mesotrophic peat. Thus, a more substantial change occurs in the ecological structure of plant communities on high-carbonate clays during their hydromorphic transformation compared to the typical mesotrophic paludification of dark-coniferous forests on loams

Evidence for a local reef eclipse in a shallow marine carbonate environment following the regional extinction of archaeocyaths in Laurentia (Stage 4, Cambrian)

Archaeocyathan sponges were the dominant metazoan framework builders during Series 2 of the Cambrian. After their near extinction during the Toyonian stage (middle Stage 4), this important ecological role was eventually filled by robustly skeletonized lithistid sponges. However, the exact timing of ecological restructuring is not well understood and was likely not contemporaneous across different paleocontinents. For example, reefs from the Wuliuan of China appear to show rapid replacement of archaeocyaths with lithistid sponges, yet the earliest occurrence of lithistids in Laurentia is not until the early Furongian. In this study, we explore the Mule Spring Limestone of Nevada, which contains shallow water carbonate environments from the immediate aftermath of the regional archaeocyathan extinction, for signs of reef-building activity. Within this formation, we find evidence of sparse microbial-built leolites and some potentially poorly preserved metazoan organisms. However, the totality of our field observations and thin-section point counts suggest that there was no substantial reef-building activity by either microbial or metazoan organisms within our study locality. Our data suggest the occurrence of a local reef eclipse during this interval for the locality investigated. We also incorporate geochemical proxies to determine paleoredox conditions, which suggest well-oxygenated marine conditions through the period of interest. Lack of hardground substrate is proposed as the cause for this gap in the reef record. These results show that a temporary loss of framework-building activity occurred after the regional extinction of archaeocyaths and demonstrates the ecological impact of losing framework builders on a reef environment.

China's Belt and Road Initiative and the emerging geographies of global urbanisation

China's Belt and Road Initiative (BRI) is heralded as the largest investment in infrastructure in history and is expected to re‐shape the geographies of urbanisation in the coming decades. In this paper we review the burgeoning, yet still embryonic literature on the BRI. Our aim is to move beyond currently dominant framings of the BRI as a geopolitical or economic strategy that tend to overlook the complex embeddedness of infrastructure. Drawing on theories of planetary urbanisation, we argue that the BRI constitutes a form of urbanisation that is bound up with the socio‐spatial and ecological restructuring of global capitalism. We illustrate this by mapping and analysing energy projects under the BRI. Overall, we outline a research agenda on the BRI that calls for (1) a more nuanced analysis of its spatial and scalar politics; (2) approaching the BRI as a distinctly urban question; and (3) a disruption of the dominant China‐centric discussions through critical in‐depth case‐study analysis.

ОСОБЛИВОСТІ МЕХАНІЗМУ РЕСУРСОЗБЕРЕЖЕННЯ В СІЛЬСЬКОМУ ГОСПОДАРСТВІ

Introduction. An important task of governing upon European principles is to reduce the development differentiation of individual territories without destroying established models of socio-economic structure of the territorial communities, which updates the study of the resource use peculiarities in agriculture. The purpose of the article is to study the features of the resource saving mechanism in agriculture. Results. The methodological basis of the study is rating applying based on the main indicators of resource use in agriculture. The study is based on the analytical scheme «resource provision – resource efficiency – resource conservation». It is justified that the current natural level of the production resources provision determines the nature and types of economic entities activities, as well as the principles and management strategy that will maximize profits. The main solution to the problem of developing a resource saving model of agricultural enterprises activities should be focused on solving the problem of the industries decoupling. Originality. The resource supply level characterizes the implementation potential of an economic initiative in the agriculture field, namely the provision of natural resources and infrastructure required to form the necessary production capacity and opportunities for products profitable sales to other participants of the national economy. The transition to an innovative technological way of development in agriculture should be based on the identified priorities in order to form a national innovation system and a holistic structure of the scientific and technical complex capable of functioning steadily under the conditions of globalization. Practical importance. It is concluded that the main directions of innovative development on the basis of resource saving should be the following: ecological restructuring and ecological modernization of production, which implies a change in the sectoral structure by reducing the demand for products of environmentally eco unfriendly industries or by modernizing the enterprises.

Stable isotope record implicates aridification without warming during the late Capitanian mass extinction

The late Capitanian mass extinction (~260millionyears ago) represents one of the greatest biotic perturbations of the Phanerozoic and was the earliest mass extinction to affect terrestrial tetrapods and ecosystems. In the past, this extinction has been largely associated with taxonomic loss and ecological restructuring in marine environments but more recently it has also been recognised in terrestrial ecosystems. Though various environmental mechanisms have been proposed for the former, little evidence has yet been presented for the cause of terrestrial extinctions. We determined the stable oxygen and carbon isotope compositions of dentine apatite from twenty-eight specimens of the dicynodont therapsid Diictodon feliceps, to investigate the potential role of climate in driving terrestrial tetrapod extinctions. Studied specimens were recovered from a 270m stratigraphic interval constraining the peak in tetrapod extinction rates in the uppermost Abrahamskraal Formation in the well-sampled main Karoo Basin of South Africa. Our results demonstrate a positive excursion of δ13C values coinciding with the extinction peak that is followed by a return to pre-extinction δ13C values, suggesting a local increase in aridity at the time of the extinction. For the same time interval, the δ18O values did not demonstrate statistically significant changes, suggesting constant temperature in the South African paleoenvironment. This unusual increase in aridity but not in temperature has been interpreted as the possible result of orogenesis in the Cape Fold Mountain source along the southern margin of Gondwana.

Quantitative analysis of the ecological dominance of benthic disaster taxa in the aftermath of the end-Permian mass extinction

AbstractThe end-Permian mass extinction, the largest extinction of the Phanerozoic, led to a severe reduction in both taxonomic richness and ecological complexity of marine communities, eventually culminating in a dramatic ecological restructuring of communities. During the Early Triassic recovery interval, disaster taxa proliferated and numerically dominated many marine benthic invertebrate assemblages. These disaster taxa include the bivalve generaClaraia,Unionites,Eumorphotis, andPromyalina, and the inarticulate brachiopodLingularia. The exact nature and extent of their dominance remains uncertain. Here, a quantitative analysis of the dominance of these taxa within the fossil communities of Panthalassa and Tethys benthic realms is undertaken for the stages of the Early Triassic to examine temporal and regional changes in disaster-taxon dominance as recovery progresses. Community dominance and disaster-taxon abundance is markedly different between Panthalassic and Tethyan communities. In Panthalassa, community evenness is low in the Induan stage but increases significantly in the Smithian and Spathian. This is coincident with a significant decrease in the relative abundance and occurrence frequency of the disaster taxa, most notably of the low-oxygen-affinity taxaClaraiaandLingularia. While the disaster taxa are present in post-Induan assemblages, other taxa, including two articulate brachiopod genera, outrank the disaster taxa in relative abundance. In the Tethys, assemblages are generally more even than contemporaneous Panthalassic assemblages. We observe an averaged trend toward more even communities with fewer disaster taxa in both Panthalassic and Tethyan assemblages over time.

Resiliency in Recovery

Hurricane Katrina thoroughly restructured New Orleans as a news environment. In the recovery period, New Orleans also lost its daily, printed newspaper when the venerated, Pulitzer Prize-winning Times-Picayune transitioned to a reduced print delivery, digital-driven format. At the same time, the uptick in public interest surrounding institutional corruption post-Katrina left a heightened civic need for newswork that fulfills the social responsibility ethic of journalistic practice. This research—founded upon 92 days of on-the-ground fieldwork and 60 in-depth interviews with newsworkers—explores the nature of accountability reporting post-Katrina. More specifically, this work traces three phases of ecological restructuring that reordered practitioner routines, fostering the growth of slow journalism in the Crescent City.

Ecological consequences of the Guadalupian extinction and its role in the brachiopod-mollusk transition

AbstractThe Guadalupian (middle Permian) extinction may have triggered substantial ecological restructuring in level-bottom communities, such as turnover in dominant brachiopod genera or a shift from abundant brachiopods to mollusks, despite comparatively minor taxonomic losses. However, ecological changes in relative abundance have been inferred from limited data; as a result, constraints on important shifts like the brachiopod-mollusk transition are imprecise. Here, I reevaluate the magnitude of ecological shifts during the Guadalupian–Lopingian (G-L) interval by supplementing previous census counts of silicified assemblages with counts from non-silicified assemblages and global occurrence data, both sourced from the Paleobiology Database. Brachiopod occurrences are consistent with more pronounced faunal composition changes from the Guadalupian to Lopingian than among stages within those intervals, but only in Iran and South China, and not in Pakistan or a Tethys-wide data set. In Iran and South China, Bray-Curtis dissimilarity values comparing occurrence frequencies between adjacent stages were elevated across the G-L transition, although other intervals exhibited similarly large shifts. However, genus occurrence frequencies were less strongly correlated or were anti-correlated across the G-L transition, suggesting moderate faunal turnover among dominant brachiopod genera. In contrast to previous inferences from silicified faunas, abundances of brachiopods, bivalves, and gastropods remained consistent from the Guadalupian to Lopingian in non-silicified local counts and global occurrences, implying that the brachiopod-mollusk shift did not occur until the end-Permian extinction. Ecological and taxonomic consequences were both minor in level-bottom settings, suggesting that severe environmental perturbations may not be necessary to explain biotic changes during the Guadalupian-Lopingian transition.

Climate change forces new ecological states in tropical Andean lakes.

Air temperatures in the tropical Andes have risen at an accelerated rate relative to the global average over recent decades. However, the effects of climate change on Andean lakes, which are vital to sustaining regional biodiversity and serve as an important water resource to local populations, remain largely unknown. Here, we show that recent climate changes have forced alpine lakes of the equatorial Andes towards new ecological and physical states, in close synchrony to the rapid shrinkage of glaciers regionally. Using dated sediment cores from three lakes in the southern Sierra of Ecuador, we record abrupt increases in the planktonic thalassiosiroid diatom Discostella stelligera from trace abundances to dominance within the phytoplankton. This unprecedented shift occurs against the backdrop of rising temperatures, changing atmospheric pressure fields, and declining wind speeds. Ecological restructuring in these lakes is linked to warming and/or enhanced water column stratification. In contrast to seasonally ice-covered Arctic and temperate alpine counterparts, aquatic production has not increased universally with warming, and has even declined in some lakes, possibly because enhanced thermal stability impedes the re-circulation of hypolimnetic nutrients to surface waters. Our results demonstrate that these lakes have already passed important ecological thresholds, with potentially far-reaching consequences for Andean water resources.

Ecological modernisation, industry policy and the Australian automotive industry, 2007–13

Ecological modernisation (EM), in theory and practice, has increasingly become central to contemporary state environmental reform agendas. EM's allure lies in its central tenet that the contemporary institutions of capitalism can be ecologically adapted to achieve ‘win–win’ economic and environmental outcomes. How government policy can best accomplish this aim is contested, however, with weak and strong EM approaches advocating different roles for the state in facilitating ecological restructuring. The latter approaches argue that for EM processes to be successful, state intervention via ecological industrial policy is required. This article makes a unique contribution to the industry policy and EM debate by assessing the manner in which EM was conceptualised and implemented within the Australian government's automotive industry policy between 2007 and 2013. This analysis raises issues about the institutional capacity of states to pursue either weak or strong forms of EM.生态现代化在理论上和实践上日益成为当代国家环境改革的中心议题。环境现代化所以诱人在于其核心原则：当代资本主义体制生态上可以取得经济、环境的双赢结果。不过政府政策如何实现这一目标确是挑战，生态现代化有强、弱二途，政府在促进生态重构时扮演不同的角色。按强势思路，要想生态现代化成功，需要国家通过生态产业政策进行干预。本文对2007至2013年澳大利亚政府的汽车产业政策形成和实施的方式做了评估，希望以此对产业政策以及生态现代化的辩论有所助益。本文还提出了国家实施强、弱生态现代化的体制能力的问题。

THE LAST GASP: TRACE FOSSILS TRACK DEOXYGENATION LEADING INTO THE FRASNIAN-FAMENNIAN EXTINCTION EVENT

ABSTRACT The Frasnian–Famennian boundary is correlated with one of several Late Devonian extinction pulses that resulted in a significant decrease in diversity as well as ecological restructuring. This event is recognized within the globally correlated Upper Kellwasser interval that is well exposed and biostratigraphically well constrained in shale units of western New York State. The ichnological and geochemical signals of the interval stratigraphically below the Upper Kellwasser event at these localities provides insight into the onset of this important extinction event. Detailed analysis of ichnogeneric composition, relative size of burrow populations, amount of bioturbation, and trace metal concentrations vary in concert. Deep-penetrating, pyritized Skolithos burrows terminate abruptly at a thin, laminated black shale interval with enriched Mo levels, up to 31 ppm, and are overlain by an interval of gray-green bioturbated shales dominated by Chondrites. These textural and chemical shifts reveal that b...

Solutions to the crisis? The Green New Deal, Degrowth, and the Solidarity Economy: Alternatives to the capitalist growth economy from an ecofeminist economics perspective

This article deals with three approaches conceived as alternative approaches to the capitalist growth economy: the Green New Deal, Degrowth, and the Solidarity Economy. Ecofeminist economics has much to offer to each of these approaches, but these contributions remain, as of yet, unrealized. The Green New Deal largely represents the green economy, which holds economic success as contingent upon the ecological restructuring of industrial production. The degrowth approach more fundamentally raises questions concerning the relationship between material prosperity and individual and social well-being. The principles of the solidarity economy involve the immediate implementation of the principles of self-determination and cooperation. None of these approaches takes into account the claims of ecofeminist economics; and none of them clearly view gender equity as essential to economic change. The three approaches are, however, deeply gendered in the sense that they are implicitly based on assumptions concerning women's labor in the sphere of social reproduction. This article demonstrates how each approach can be improved upon by the integration of ecofeminist economic principles in order to achieve economic change that also meets claims for gender equity.

Ecological Modernization or Sustainable Development? Vancouver's Greenest City Action Plan: The City as ‘manager’ of Ecological Restructuring

A framework for assessing cities as contributors to sustainable development (SD) is proposed. Differentiating between SD and ecological modernization (EM), we contend that even the weakest EM reforms prompt ecological restructuring (ER). Once unleashed, ER creates four problematics—ecological, economic, political and cultural—which governments at different scales must address by maintaining or challenging the status quo in relation to global structural imperatives; notably, requirements to promote economic growth and maintain legitimacy. That is, ER fosters uneven, non-linear processes of societal learning, which apply at different scales. Hence, where national governments lag behind, cities that develop ‘action plans’ may prompt SD. The framework is road tested by evaluating Vancouver's Greenest City Action Plan. We find that Vancouver does indeed push ER towards SD, especially in the political and cultural domains, even as Canada and British Columbia appear less committed. However, due to the proximity of city government to citizens' lived experiences of unsustainable development, Vancouver, like other cities, confronts a distinct kind of democratizing pressure. A future research agenda on this issue would aim to uncover how planning for SD must both foster and manage this democratizing pressure, which arises as informal (spontaneous, ‘from below’) participation meets formal (procedural, ‘top-down’) process.

Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America

The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

Environmental and biological controls on the diversity and ecology of Late Cretaceous through early Paleogene marine ecosystems in the U.S. Gulf Coastal Plain

The late Mesozoic through early Cenozoic is an interval of significant biologic turnover and ecologic reorganization within marine assemblages, but the timing and causes of these changes remain poorly understood. Here, we quantify the pattern and timing of shifts in the diversity (richness and evenness) and ecology of local (i.e., sample level) mollusk-dominated assemblages during this critical interval using field-collected and published data sets from the U.S. Gulf Coastal Plain. We test whether the biologic and ecologic patterns observed primarily at the global level during this time are also expressed at the local level, and whether the end-Cretaceous (K/Pg) mass extinction and recovery moderated these trends. To explore whether environment had any effect on these patterns, we examine data from shallow subtidal and offshore settings.Assemblages from both settings recovered to pre-extinction diversity levels rapidly, in less than 7 million years. Following initial recovery, diversity remained unchanged in both settings. The trajectory of ecological restructuring was distinct for each setting in the wake of the K/Pg extinction. In offshore assemblages, the abundance and number of predatory carnivorous taxa dramatically increased, and surficial sessile suspension feeders were replaced by more active suspension feeders. In contrast, shallow subtidal assemblages did not experience ecological reorganization following the K/Pg extinction. The distinct ecological patterns displayed in each environment follow onshore-offshore patterns of innovation, whereby evolutionary novelties first appear in onshore settings relative to offshore habitats. Increased predation pressure may explain the significant ecological restructuring of offshore assemblages, whereby the explosive radiation of predators drove changes in their prey. Habitat-specific ecological restructuring, and its occurrence solely during the recovery interval, implies that disturbance and incumbency were also key in mediating these ecological changes.