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A high degree of uncertainty exists for understanding and predicting coastal estuarine response to changing climate, land-use, and sea-level conditions, leaving geologic records as a best-proxy for constraining potential outcomes. With the majority of the world's population focused in coastal regions, understanding how local systems respond to global, regional, and even local pressures is key in developing mitigation, adaptation, and management plans. The geomorphology of Mobile Bay in southeast Alabama (USA) has evolved considerably (e.g., bayhead delta back-stepping) over the late Holocene in response to global and regional sea-level and climate change. Smaller-scale geomorphic changes (e.g., spit and beach ridge development) have also had a significant influence on the evolution of the estuary. Organic matter characteristics, inorganic sediment geochemistry, benthic microfossils, and pollen in a ~ 3500 cal yr BP sediment sequence recovered in a gravity core (20GC) from Bon Secour Bay, a small sub-bay in the southeast corner of Mobile Bay, record time-varying marine influence. Increases in marine influence during ~3500 to 2300 cal yr BP and 1930 to 1160 cal yr BP are defined as zones with high-density and pre-dominantly calcareous foraminiferal species, abundant sand (>10%) and more marine-like geochemical signatures, which contrast the low-density and pre-dominantly agglutinated foraminiferal and more terrestrially influenced estuarine muds observed in other intervals of the sedimentary record (2300–1930 and 1160–400 cal yr BP) and the modern bay. Hydrodynamic models constrained by geomorphic boundary conditions for the time ~ 3500 cal yr BP, consistent with the most prominent marine-influenced sediment, provide insight to potential coastal configuration that might have permitted such marine water intrusion into the bay. Of several scenarios evaluated, a breach in Morgan Peninsula produces tidal circulation within the basin supportive of persistent marine incursions in the bay between ~3500 to 2300 cal yr BP. The findings show that slight variations in coastal configuration can have broad-scale effects on bays and estuaries with consequences that may relate to water quality, vertebrate and invertebrate habitat, and coastal vulnerability to episodic events like (extra)tropical storms. • Paleonenvironmental data identify frequent-to-periodic marine intrusions into Mobile/Bon Secour Bays over the past 3500 years. • Hydrodynamic modeling find that breaching of Morgan Peninsula is the likely explanation of early documented marine intrusions • Paper demonstrates the utility applying scenario-based model simulations to evaluate geologic and stratigraphic interpretations [ABSTRACT FROM AUTHOR]

• A new concept (´endangered living fossil´) is proposed based on conservation and phylogenetic criteria. • Endangered, monspecific genera are good candidates to test whether they are endangered lineages of great evolutionary heritage. • California, Chile and Mediterranean Basin provide 11 examples. • They help infer causes for extinction and survival postdating historical climate changes. • We urge the IUCN to consider evolutionary criteria for species prioritization. Geography and climate have been the main drivers of evolution in recent geological epochs. While new lineages of species have been formed in the last millions of years (speciation) and others have vanished as a result of historical climate changes (extinction), some ancient lineages appear to have persisted to the present day without net diversification. In this paper, evolution of ancient lineages is addressed by combining phylogenetic and conservation approaches to test the concept of 'endangered living fossil' (ELF). Using endangered, monospecific genera as starting point, we propose three criteria to identify ELFs (in order): (1) scarcity and narrow distribution of populations, i.e. the species (and thus the genus) is categorised as either 'endangered' or 'critically endangered' using IUCN criteria; (2) evolutionary distinctiveness, i.e. phylogenetic singularity of a single-species lineage as a result of a null net diversification rate; (iii) ancient divergence, i.e. split from the closest extant relatives predating the dramatic climate changes of particular geological epochs (specifically changes since the Miocene-Pliocene boundary). The vascular flora of the Iberian Peninsula offers a suitable study system to reliably test the ELF concept. Indeed, time-calibrated phylogenies revealed that five of the six critically endangered, monospecific genera endemic to the Iberian Peninsula are ELFs. These five genera appear to have diverged from their closest relatives in the Oligocene (Gyrocaryum), Miocene (Avellara , Castrilanthemum, Gadoria) and around the Miocene-Pliocene boundary (Naufraga). This result entails long-term survival (with no net diversification) through at least three dramatic climate changes: the Messinian Salinity Crisis (late Miocene), the establishment of the mediterranean climate (Pliocene), and the glacial-interglacial cycles (Pleistocene). Using results from the literature, we found examples of ELFs for the mediterranean floras of California (Dodecahema), Chile (Avellanita , Gomortega , Legrandia) and other Mediterranean areas of Europe (Petagnaea , Phitosia). ELFs are unique and threatened lineages representing an exceptional evolutionary heritage, and therefore they should be prioritised in biodiversity research and conservation programs. [ABSTRACT FROM AUTHOR]

• The diatom content of a sediment core from the Sea of Okhotsk was studied. • Diatoms were used to reconstruct the environmental changes over the last 94 kyr. • Local warming and cooling events and fluctuations in the sea level were documented. • First report of a shift from interglacial to severe glacial conditions in the area. This paper presents the results of a study on a sediment core obtained from the southwestern part of the Sea of Okhotsk. By analyzing the diatoms in the sediment, along with the productivity proxy and ice-rafted debris data, we reconstructed the regional environmental and climatic changes occurring over last 94 kyr (sea-ice expansion, periods of active ice melting, and variations in marine plankton productivity). Local warming and cooling events occurring in the Late Pleistocene and Holocene periods, as well as transgressive-regressive fluctuations in the sea level, were documented. The shift in the relatively warm interglacial conditions to severe glaciation over 34 kyr ago that occurred in the studied area of the Sea of Okhotsk was reported for the first time. The time at which the La Pérouse Strait opened, the Soya Current input began, and the establishment of modern hydrological conditions was approximately 5.6 kyr. [ABSTRACT FROM AUTHOR]