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At least 415 records · Page 23Linked to original sources
USGS2025

Ecological thresholds and transformations due to climate change: The role of abiotic stress

An ecological threshold is the point at which a comparatively small environmental change triggers an abrupt and disproportionately large ecological response. In the face of accelerating climate change, there is concern that abrupt ecosystem transformations will become more widespread as critical ecological thresholds are crossed. There has been ongoing debate, however, regarding the prevalence of ecological thresholds across the natural world. While ecological thresholds are ubiquitous in some ecosystems, thresholds have been difficult to detect in others. Some studies have even concluded that threshold responses are uncommon in the natural world and overly emphasized in the ecological literature. As ecologists who work in ecosystems chronically exposed to high abiotic stress, we consider ecological thresholds and ecosystem transformations to be critical concepts that can greatly advance understanding of ecological responses to climate change and inform ecosystem management. But quantifying ecological thresholds can be challenging, if not impossible, without data that are strategically collected for that purpose. Here, we present a conceptual framework built upon linkages between abiotic stress, climate-driven ecological threshold responses, and the risk of ecosystem transformation. We also present a simple approach for quantifying ecological thresholds across abiotic stress gradients. We hypothesize that climate-driven threshold responses are especially influential in ecosystems chronically exposed to high abiotic stress, where autotroph diversity is low and foundation species play a prominent ecological role. Abiotic conditions in these environments are often near physiological tolerance limits of foundation species, which means that small abiotic changes can trigger landscape-level ecological transformations. Conversely, the alleviation of stress near thresholds can allow foundation species to thrive and spread into previously inhospitable locations. We provide examples of this climate-driven threshold behavior from four high-stress environments: coastal wetlands, coral reefs, drylands, and alpine ecosystems. Our overarching aim in this review is to clarify the strong relationships between abiotic stress, climate-driven ecological thresholds, and the risk of ecosystem transformation under climate change.

Ecosphere↗
USGS2006

Genesis of marine terrace soils, Barbados, West Indies: evidence from mineralogy and geochemistry

Well-developed, clay-rich soils dominated by interstratified kaolinite-smectite are found on the uplifted coral reef terraces on the island of Barbados. The reef limestone is unlikely to have been the soil parent material however, because it is 98% CaCO 3 and geomorphic evidence argues against the 20 m of reef solution required to produce the soils by this process. The mineralogy of the sand, silt, and clay fractions of the soils, and trace element geochemistry, suggest that aeolian materials carried on the trade winds from Africa, volcanic ash from the island of St. Vincent, and quartz from Tertiary bedrock on the island itself are the parent materials for the soils. -Authors

Earth Surface Processes and Landforms↗
USGS2017

Last interglacial climates

The last interglacial, commonly understood as an interval with climate as warm or warmer than today, is represented by marine isotope stage (MIS) 5e, which is a proxy record of low global ice volume and high sea level. It is arbitrarily dated to begin at approximately 130,000 yr B.P. and end at 116,000 yr B.P. with the onset of the early glacial unit MIS 5d. The age of the stage is determined by correlation to uranium-thorium dates of raised coral reefs. The most detailed proxy record of interglacial climate is found in the Vostok ice core where the temperature reached current levels 132,000 yr ago and continued rising for another two millennia. Approximately 127,000 yr ago the Eemian mixed forests were established in Europe. They developed through a characteristic succession of tree species, probably surviving well into the early glacial stage in southern parts of Europe. After ca. 115,000 yr ago, open vegetation replaced forests in northwestern Europe and the proportion of conifers increased significantly farther south. Air temperature at Vostok dropped sharply. Pulses of cold water affected the northern North Atlantic already in late MIS 5e, but the central North Atlantic remained warm throughout most of MIS 5d. Model results show that the sea surface in the eastern tropical Pacific warmed when the ice grew and sea level dropped. The essentially interglacial conditions in southwestern Europe remained unaffected by ice buildup until late MIS 5d when the forests disappeared abruptly and cold water invaded the central North Atlantic ca. 107,000 yr ago. ?? 2002 University of Washington.

Quaternary Research↗
USGS2011

Porosity variability in limestone sequences

Porosity is the state of being porous, as measured by the percentage of bulk volume of a rock or soil that is occupied by space, whether isolated or connected. In hydrocarbon-bearing limestone settings, subsurface porous strata containing the oil or gas usually underlie non-porous caprock through which hydrocarbons cannot pass. In settings, subsurface freshwater aquifers beneath caprock can become contaminated by saltwater intrusion during periods of drought. Islands of the Florida Keys consist of two types of emergent 125-ka limestone, a highly porous fossil coral reef with large voids and a less porous oolite with small grains and interstices. Both limestones are capped by impervious laminated Holocene calcrete whose dimensions differ greatly (Figure 1a and b). Porosity variability in the limestones is thought to be the cause. The less permeable oolite retained rainfall moisture longer, allowing longer periods of calcrete buildup. Reddish and brownish layers in both illustrated calcrete samples represent periods of influx of non-carbonate minerals on African dust. The hiatus or gap in these rock records represents an interval of >115 kyr during which no marine or terrestrial deposition is recorded.

Book chapter↗
USGS1991

Geology and petrology of Mahukona Volcano, Hawaii

The submarine Mahukona Volcano, west of the island of Hawaii, is located on the Loa loci line between Kahoolawe and Hualalai Volcanoes. The west rift zone ridge of the volcano extends across a drowned coral reef at about-1150 m and a major slope break at about-1340 m, both of which represent former shoreines. The summit of the volcano apparently reached to about 250 m above sea level (now at-1100 m depth) did was surmounted by a roughly circular caldera. A econd rift zone probably extended toward the east or sutheast, but is completely covered by younger lavas from the adjacent subaerial volcanoes. Samples were vecovered from nine dredges and four submersible lives. Using subsidence rates and the compositions of flows which drape the dated shoreline terraces, we infer that the voluminous phase of tholeiitic shield growth ended about 470 ka, but tholeiitic eruptions continued until at least 435 ka. Basalt, transitional between tholeiitic and alkalic basalt, erupted at the end of tholeiitic volcanism, but no postshield-alkalic stage volcanism occurred. The summit of the volcano apparently subcided below sea level between 435 and 365 ka. The tholeiitic lavas recovered are compositionally diverse.

Hawaii↗
USGS2002

Coastal geoindicators of environmental change in the humid tropics

The primary geoindicators appropriate for monitoring environmental changes in the humid tropics are transitory surface water levels, shoreline position, wetlands distribution, coral reefs, landforms, and sediment sequence and composition. Lateral zonations and temporal successions of vegetation also can be used as geoindicators of riverine and shoreline changes. All of these coastal geoindicators are sensitive to regional tectonic processes and anthropogenic alterations and they typically reflect significant changes in coastal conditions such as fluvial processes, coastal energy, water quality, relative sea level, and sediment supply. Where humid tropical coasts coincide with active tectonic margins, indicators of seismic activity are critical to understanding Coastal changes associated with co-seismic subsidence or uplift, tsunamis, and liquefaction of coastal sediments. Coastal landforms and sedimentary deposits that record late Quaternary environmental changes include perched fluvial and marine terraces, delta-plain morphologies, crevassesplay deposits, peats and other paleosols, beach ridges, mud capes, and mud volcanoes. Although these features and deposits typically reflect environmental changes spanning more than 100 years, they are relevant to modern processes, management of coastal lands and resources, and prediction of future conditions. In some regions of the humid tropics, large coastal areas are unaffected by hurricanes or typhoons. Nevertheless, these tropical coasts are vulnerable to other non-storm processes, such as El Nin??o events, tsunamis, and monsoons that increase water levels, and cause widespread flooding and beach erosion. The environmental and political significance of coastal geoindicators increases when they are integrated and applied to issues of human safety and health such as hazards mapping, risk assessment, and dispersion of contaminated sediments. However, to be relevant, those socio-environmental applications demand accurate predictions of future trends and rates of change.

Environmental Geology↗
USGS2014

Disturbance to desert soil ecosystems contributes to dust-mediated impacts at regional scales

This review considers the regional scale of impacts arising from disturbance to desert soil ecosystems. Deserts occupy over one-third of the Earth’s terrestrial surface, and biological soil covers are critical to stabilization of desert soils. Disturbance to these can contribute to massive destabilization and mobilization of dust. This results in dust storms that are transported across inter-continental distances where they have profound negative impacts. Dust deposition at high altitudes causes radiative forcing of snowpack that leads directly to altered hydrological regimes and changes to freshwater biogeochemistry. In marine environments dust deposition impacts phytoplankton diazotrophy, and causes coral reef senescence. Increasingly dust is also recognized as a threat to human health.

Biodiversity and Conservation↗
USGS2010

Geomorphic and stratigraphic evidence for an unusual tsunami or storm a few centuries ago at Anegada, British Virgin Islands

Waters from the Atlantic Ocean washed southward across parts of Anegada, east-northeast of Puerto Rico, during a singular event a few centuries ago. The overwash, after crossing a fringing coral reef and 1.5 km of shallow subtidal flats, cut dozens of breaches through sandy beach ridges, deposited a sheet of sand and shell capped with lime mud, and created inland fields of cobbles and boulders. Most of the breaches extend tens to hundreds of meters perpendicular to a 2-km stretch of Anegada’s windward shore. Remnants of the breached ridges stand 3 m above modern sea level, and ridges seaward of the breaches rise 2.2–3.0 m high. The overwash probably exceeded those heights when cutting the breaches by overtopping and incision of the beach ridges. Much of the sand-and-shell sheet contains pink bioclastic sand that resembles, in grain size and composition, the sand of the breached ridges. This sand extends as much as 1.5 km to the south of the breached ridges. It tapers southward from a maximum thickness of 40 cm, decreases in estimated mean grain size from medium sand to very fine sand, and contains mud laminae in the south. The sand-and-shell sheet also contains mollusks—cerithid gastropods and the bivalve Anomalocardia—and angular limestone granules and pebbles. The mollusk shells and the lime-mud cap were probably derived from a marine pond that occupied much of Anegada’s interior at the time of overwash. The boulders and cobbles, nearly all composed of limestone, form fields that extend many tens of meters generally southward from limestone outcrops as much as 0.8 km from the nearest shore. Soon after the inferred overwash, the marine pond was replaced by hypersaline ponds that produce microbial mats and evaporite crusts. This environmental change, which has yet to be reversed, required restriction of a former inlet or inlets, the location of which was probably on the island’s south (lee) side. The inferred overwash may have caused restriction directly by washing sand into former inlets, or indirectly by reducing the tidal prism or supplying sand to post-overwash currents and waves. The overwash happened after A.D. 1650 if coeval with radiocarbon-dated leaves in the mud cap, and it probably happened before human settlement in the last decades of the 1700s. A prior overwash event is implied by an inland set of breaches. Hypothetically, the overwash in 1650–1800 resulted from the Antilles tsunami of 1690, the transatlantic Lisbon tsunami of 1755, a local tsunami not previously documented, or a storm whose effects exceeded those of Hurricane Donna, which was probably at category 3 as its eye passed 15 km to Anegada’s south in 1960.

Natural Hazards↗
USGS2009

Coastline degradation as an indicator of global change

Finding a climate change signal on coasts is more problematic than often assumed. Coasts undergo natural dynamics at many scales, with erosion and recovery in response to climate variability such as El Niño, or extreme events such as storms and infrequent tsunamis. Additionally, humans have had enormous impacts on most coasts, overshadowing most changes that one can presently attribute directly to climate change. Each area of coast is experiencing its own pattern of relative sea-level change and climate change, making discrimination of the component of degradation that results from climate change problems. The best examples of a climate influence are related to temperature rise at low and high latitudes, as seen by the impacts on coral reefs and polar coasts, respectively. Observations through the twentieth century demonstrate the importance of understanding the impacts of sea-level rise and climate change in the context of multiple drivers of change; this will remain a challenge under a more rapidly changing climate. Nevertheless, there are emerging signs that climate change provides a global threat—sea ice is retreating, permafrost in coastal areas is widely melting. Reefs are bleaching more often, and the sea is rising—amplifying widespread trends of subsidence and threatening low-lying areas. To enhance the sustainability of coastal systems, management strategies will also need to address this challenge, focusing on the drivers that are dominant at each section of coast. Global warming through the twentieth century has caused a series of changes with important implications for coastal areas. These include rising temperatures, rising sea level, increasing CO2 concentrations with an associated reduction in seawater pH, and more intense precipitation on average.

Book chapter↗
USGS2026

Erosion and transport of sediments in watersheds of southwest Puerto Rico determined from strontium isotopes and mixing models

Sediment outflow from streams to coastal regions can adversely affect water quality and the health of ecosystems including Puerto Rico's southwestern carbonate platform with shallow marine communities. Knowledge of sediment provenance and erosional areas would aid effective restoration to reduce excessive sedimentation. Strontium (Sr) isotopic ratios ( 87 Sr/ 86 Sr) can be used to differentiate between sediment eroded into streams from different lithologies, or rock types, and used in mixing models to estimate proportions of source materials in downstream mixtures. The goal of this study was to use Sr isotopes to differentiate between river sediments in drainages with distinct geologies and present a case study where Sr isotope mixing models are used to identify sediment sourcing to Río Loco and Bahía de Guánica, a priority watershed of the U.S. Coral Reefs Task Force. For the Río Loco watershed, model results indicate that serpentinites in the uplands contributed approximately 71 % of sediment to Bahía de Guánica. About 21 % of sediment was from trachy-andesitic basalts in the foothills, and the remaining 8 % originated from sources on the coastal plain. Neither the uppermost headwater region of Río Loco, the Canal Principal De Riego Valle De Lajas, nor the tributary Quebrada Susúa appeared to be significant sources of sediment to Río Loco's mainstem or Bahía de Guánica at the time of the study. Our results demonstrate that sediment from the serpentinite-bearing areas of Río Loco watershed was effectively transported to the lowlands, which then discharge into Guánica Bay, and highlight the potential use of Sr isotopes as tracers of sediment provenance. This will, in turn, enable better science-based restoration efforts aimed at reducing terrestrial sediment erosion and impacts to marine ecosystems.

Puerto Rico↗
USGS2009

A mosaic of diverse ideas: The ecological legacy of J. Frederick Grassle

During the 40 years (and counting) of his scientific career, J. Frederick Grassle has made fundamental contributions to our understanding of marine ecosystems from coral reefs to deep-sea sediments. His advocacy and passion for marine biodiversity in the form of myriad groundbreaking studies and influential reviews, his generosity of ideas and capacity to catalyze and inspire those working with him as well as the science community in general, his breakthroughs in improved ocean observation, his marine science infrastructure initiatives, together with his tireless persistence, have helped lead to major shifts in approaches to marine science and the shape of modern ocean studies to one that favours multidisciplinary research, teamwork, continuous, long-term observation, in situ experimentation, recognition of the importance of marine biodiversity, and global cooperation on research and data sharing. In shallow-water ecology, he co-discovered sibling species of Capitella spp., important not only because it is a key pollution indicator but also because the work helped to pave the way for the discovery of numerous sibling species in other taxa with major ramifications for ecological understanding. He was also a key player in the West Falmouth oil spill study which, along with complementary mesocosm experiments, remains one of the most important and detailed studies of its kind. He was also a lead player in the first biological expedition to hydrothermal vents and wrote the seminal articles that helped to inspire the flurry of vent research that followed. He is perhaps best known for his deep-sea work, where he brought submersibles to the forefront as a sampling tool, brought experimental manipulative studies to the primarily descriptive discipline of deep-sea benthic ecology, and generated tremendous excitement, debate, and rekindled interest in marine biodiversity with the first quantitative estimate of global deep-sea diversity. His efforts to document marine biodiversity resulted in the international Census of Marine Life, and his emphasis on the need for continuous, long-term ocean observation has led to breakthroughs in international cooperation in cabled observatories such as LEO-15. These efforts have also enhanced efforts to integrate ocean data on a global scale in platforms such as the Ocean Biogeographic Information System (OBIS). The diversity of his contributions to marine science mirror the immense marine diversity he has recognized, documented, and championed so effectively over the last four decades.

Deep-Sea Research Part II: Topical Studies in Ocea↗
USGS2014

Mercury dynamics in a coastal aquifer: Maunalua Bay, Oʻahu, Hawaiʻi

We evaluated the influence of groundwater–seawater interaction on mercury dynamics in Maunalua Bay, a coral reef ecosystem located on the south shore of Oʻahu, Hawaiʻi, by combining geochemical data with submarine groundwater discharge (SGD) rates. During a rising tide, unfiltered total mercury (U-HgT) concentrations in seawater increased from ∼6 to 20 pM at Black Point (west Bay) and from ∼2.5 to 8 pM at Niu (central Bay). We attribute this change to an increase in suspended particulate matter at high tide. Approximately 90% of mercury in groundwater at Niu was in the filtered (<0.45 μm) fraction, with a concentration of ∼4 pM. Groundwater discharge during a period of amplified SGD at Niu appeared to contribute to an increase in total mercury concentrations in filtered seawater (F-HgT; 1.2 to 2.4 pM) and in unfiltered seawater (U-HgT; 2.5 to 3.2 pM). The larger magnitude of change in F-HgT relative to U-HgT suggests mercury complexation and/or solubility dynamics in seawater were altered by the addition of groundwater. We used site specific 222 Rn derived SGD flux estimates and groundwater F-HgT concentrations to calculate mercury loadings at Black Point (∼3 nmol m −2 d −1 ) and at Niu (∼1 nmol m −2 d −1 ). We calculated a weighted average Maunalua Bay groundwater mercury flux of 0.68 ± 0.67 mol yr −1 by combining the proportional flux of F-HgT from three distinct SGD zones, and place these results into a broader context by comparing and contrasting flux estimates from locations around the world. Results from existing SGD studies should be evaluated to develop future sampling strategies that address more targeted questions about mercury biogeochemical cycling at the groundwater–seawater interface.

Hawai'i↗
USGS2016

Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

Study region The study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef. Study focus Coastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii. New hydrological insights for the region Estimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222 Rn ( t 1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron ( 220 Rn, t 1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

Hawaii↗
USGS2009

Late Pleistocene Sea level on the New Jersey Margin: Implications to eustasy and deep-sea temperature

We assembled and dated a late Pleistocene sea-level record based on sequence stratigraphy from the New Jersey margin and compared it with published records from fossil uplifted coral reefs in New Guinea, Barbados, and Araki Island, as well as a composite sea-level estimate from scaling of Red Sea isotopic values. Radiocarbon dates, amino acid racemization data, and superposition constrain the ages of large (20-80??m) sea-level falls from New Jersey that correlate with Marine Isotope Chrons (MIC) 2, 3b, 4, 5b, and 6 (the past 130??kyr). The sea-level records for MIC 1, 2, 4, 5e, and 6 are similar to those reported from New Guinea, Barbados, Araki, and the Red Sea; some differences exist among records for MIC 3. Our record consistently provides the shallowest sea level estimates for MIC3 (??? 25-60??m below present); it agrees most closely with the New Guinea record of Chappell (2002; ??? 35-70??m), but contrasts with deeper estimates provided by Araki (??? 85-95??m) and the Red Sea (50-90??m). Comparison of eustatic estimates with benthic foraminiferal ?? 18 O records shows that the deep sea cooled ??? 2.5????C between MIC 5e and 5d (??? 120-110??ka) and that near freezing conditions persisted until Termination 1a (14-15??ka). Sea-level variations between MIC 5b and 2 (ca. 90-20??ka) follow a well-accepted 0.1???/10??m linear variation predicted by ice-growth effects on foraminiferal ?? 18 O values. The pattern of deep-sea cooling follows a previously established hysteresis loop between two stable modes of operation. Cold, near freezing deep-water conditions characterize most of the past 130??kyr punctuated only by two warm intervals (the Holocene/MIC 1 and MIC 5e). We link these variations to changes in Northern Component Water (NCW). ?? 2009 Elsevier B.V. All rights reserved.

Global and Planetary Change↗
USGS2010

Shell anomalies observed in a population of Archaias angulatus (Foraminifera) from the Florida Keys (USA) sampled in 1982-83 and 2006-07

Archived specimens of Archaias angulatus collected live at a depth of < 2. m in John Pennekamp Coral Reef State Park, Key Largo, Florida, in June, September and December 1982, and March 1983, were compared to specimens collected live from the same site and months in 2006-07. Shells were examined using light microscopy for anomalous features, which were then documented using scanning electron microscopy. Seven different types of morphological abnormalities and five different surface texture anomalies were observed. Physical abnormalities included profoundly deformed, curled, asymmetrical, and uncoiled shells, irregular suture lines, surface protrusions, and breakage/repair. Textural anomalies observed were surface pits, dissolution features, microborings, microbial biofilms, and the presence of epibionts including bryzoans, cyanobacteria and foraminifers. The same kinds of features were found in this A. angulatus population in both 1982-83 collections and 2006-07 collections. Within-date variability was higher in specimens collected in 1982-83, while between-date variability was higher in 2006-07; overall the range of variability was similar. Given that the site was originally chosen for study because these foraminifers were so abundant, the lack of significant change indicates that the variability of the geochemical habitat is still within the range that A. angulatus can thrive. ?? 2010.

Marine Micropaleontology↗
USGS2018

Mapping elemental contamination on Palmyra Atoll National Wildlife Refuge

Palmyra Atoll, once a WWII U.S. Navy air station, is now a U.S. National Wildlife Refuge with nearly 50 km 2 of coral reef and 275 ha of emergent lands with forests of Pisonia grandis trees and colonies of several bird species. Due to the known elemental and organic contamination from chemicals associated with aviation, power generation and transmission, waste management, and other air station activities, a screening survey to map elemental concentrations was conducted. A map of 1944 Navy facilities was georeferenced and identifiable features were digitized. These data informed a targeted survey of 25 elements in soils and sediment at locations known or suspected to be contaminated, using a hand-held X-ray fluorescence spectrometer. At dozens of locations, concentrations of elements exceeded established soil and marine sediment thresholds for adverse ecological effects. Results were compiled into a publicly available geospatial dataset to inform potential remediation and habitat restoration activities.

Marine Pollution Bulletin↗
USGS2023

A new deglacial climate and sea-level record from 20 to 8 ka from IODP381 site M0080, Alkyonides Gulf, eastern Mediterranean

Records of relative sea-level rise for the last deglaciation are mostly limited to coral reef records and geophysical model estimates, but observational data from regions with temperate climates is sparse. We present a new relative climatic and regional sea-level rise record for glacial Termination 1 (Marine Isotope Stages [MIS] 2–1) based on ostracode paleoecology from the upper 8 m of the International Ocean Discovery Program (IODP) Site M0080 collected on Expedition 381, in the Gulf of Alkyonides, eastern Corinth basin of the Mediterranean Sea. Results show a series of major faunal transitions from lacustrine (Ponto-Caspian, Lake Corinth) glacial-age assemblages to fully marine (Mediterranean) interglacial assemblages between 20 and 8 ka. During glacial and early deglacial intervals, the Gulf of Alkyonides was characterized by non-marine lacustrine conditions with episodic sediment input from coastal, saline lake environments. Relatively stable lake shoreline conditions marked by the distinctive Tuberoloxoconcha sp. Existed from ∼17.5 to 15 ka. During the peak deglacial interval, the BØlling-AllerØd (B-A, ∼15–13.5 ka), rapid sea-level rise is indicated by a fully marine ostracode fauna colonization, which persisted from 13.5 to 7.5 ka (Late Pleistocene-Early to Middle Holocene).

Quaternary Science Reviews↗
USGS2024

How long have we been mistaken? Multi-tools shedding light into the systematics of the widespread deep-water genus Madrepora Linnaeus, 1758 (Scleractinia)

Deep-water coral reefs are found worldwide and harbor biodiversity levels that are comparable to their shallow-water counterparts. However, the genetic diversity and population structure of deep-water species remain poorly explored, and historical taxonomical issues still need to be resolved. Here we used microsatellite markers as well as ultraconserved elements (UCE) and exons to shed light on the population structure, genetic diversity, and phylogenetic position of the genus Madrepora , which contains M. oculata , one of the most widespread scleractinian species. Population structure of 107 samples from three Southwestern Atlantic sedimentary basins revealed the occurrence of a cryptic species, herein named M. piresae sp. nov. (authored by Kitahara, Capel and Zilberberg), which can be found in sympatry with M. oculata . Phylogeny reconstructions based on 134 UCEs and exon regions corroborated the population genetic data, with the recovery of two well-supported groups, and reinforced the polyphyly of the family Oculinidae. In order to better accommodate the genus Madrepora , while reducing taxonomical confusion associated with the name Madreporidae, we propose the monogeneric family Bathyporidae fam. nov. (authored by Kitahara, Capel, Zilberberg and Cairns). Our findings advance the knowledge on the widespread deep-water genus Madrepora , resolve a long-standing question regarding the phylogenetic position of the genus , and highlight the need of a worldwide review of the genus.

Molecular Phylogenetics and Evolution↗