Liviu Giosan

• PhD
• Geoscuentist at Woods Hole Oceanographic Institution

Indian summer monsoon (ISM) hydrology fuels biogeochemical cycling across South Asia and the Indian Ocean, exerting a first-order control on food security in Earth’s most densely populated areas. Although the ISM is projected to intensify under continued greenhouse forcing, substantial uncertainty surrounds anticipating its impacts on future Indian...

During the Quaternary Period, major fluctuations between wet and dry climate have been implicated in the expansion and contraction of the Amazon forests and associated changes in their biodiversity. Yet, most of the Quaternary Period in the Amazon remains poorly known because of the complete lack of long geologic records from the Amazon basin. Here...

The Mississippi River Delta (MRD) is a global natural and economic asset and socioeconomic hub with an extensive fishery, major petrochemical complexes, and the largest global commodity port. During the twentieth century, >25% of MRD coastal wetlands were lost. Climate forcings threatening the MRD include extreme precipitation, increasing river dis...

New research at Tell al-Hiba, ancient Lagash, has uncovered evidence of extensive flooding and sitewide destruction in the latter half of the third millennium BC. Specifically, we characterize and date a prominent water-formed feature that crosses the heart of Lagash’s former temple district. Geoarchaeological trenching and geophysical prospection...

New research at Tell al-Hiba, ancient Lagash, has revealed evidence of significant flooding and widespread destruction in the Mesopotamian city during the Early Dynastic period. We identify and date a prominent water-formed feature that cut through its primary temple district. Geoarchaeological trenching and geophysical prospection indicate that an...

Kori Creek is one of the most important creeks along the coastline of the Kachchh basin and forms a connecting passage between the Arabian Sea and the Great Rann of Kachchh (GRK) basin. Historically, this region has supported maritime activities between the Kachchh region and Sindh (now part of Pakistan) and witnessed significant landscape changes...

Deltas have provided fertile farmland, productive fishing, and access to trade routes for millennia. Today, more than five hundred million people live on deltas and coastal urban areas. Yet deltas are also incredibly vulnerable to the pressures of climate change. This Voices asks: what are the opportunities and barriers to adaptation for delta comm...

Deltas are subaerial landforms that cap underlying deposits with subaqueous extensions that result from a river feeding sediment directly into a standing body of water at a rate that overwhelms any effective dispersal processes derived from the ambient basin. This definition encapsulates both the terrestrial surface expression and the geological fo...

Monsoonal rivers play an important role in the land-to-sea transport of soil-derived organic carbon (OC). However, spatial and temporal variation in the concentration, composition, and fate of this OC in these rivers remains poorly understood. We investigate soil-to-sea transport of soil OC by the Godavari River in India using glycerol dialkyl glyc...

Monsoonal rivers play an important role in the land-to-sea transport of soil-derived organic carbon (OC). However, spatial and temporal variation in the concentration, composition, and fate of OC in these rivers remains poorly understood. We investigate soil-to-sea transport of OC by the Godavari River in India using branched glycerol dialkyl glyce...

During the last deglaciation substantial volumes of meltwater from the decaying Laurentide Ice Sheet were supplied to the Arctic, Gulf of Mexico and North Atlantic along different drainage routes, sometimes as catastrophic flood events. These events are suggested to have impacted global climate, for example initiating the Younger Dryas cold period....

The deposits of large Asian rivers with unique drainage geometries have attracted considerable attention due to their explanatory power concerning tectonism, surface uplift and upstream drainage evolution. This study presents the first petrographic, heavy mineral, Nd and Sr isotope geochemistry, and detrital zircon geochronology results from the Ho...

The Ayeyarwady River flows for 2170 km to the Andaman Sea from above 3000 m altitude in the Eastern Himalayan Syntaxis. The Ayeyarwady is one of the largest river systems in the world in terms of water and sediment discharge. The Ayeyarwady floodplains have supported agriculture through the Neolithic and successive urban civilizations since the lat...

Geological and geophysical studies suggested that the Indus River system was initiated shortly after the collision between the Indian and Eurasian Plates in Middle Eocene. The geology of the Indus drainage is largely shaped by the collision between the Indian Plate with mainland Eurasia, starting around 50 million years ago. The Indus Basin holds a...

Anthropogenic climate change and landscape alteration are two of the most important threats to the terrestrial and aquatic ecosystems of the tropical Americas, thus jeopardizing water and soil resources for millions of people in the Andean nations. Understanding how aquatic ecosystems will respond to anthropogenic stressors and accelerated warming...

Tests of planktic foraminifera are important tracers for reconstructing past oceanic environments. It is essential to have accurate information of the habitat depth of the planktic foraminiferal species whose isotopic and elemental signatures are being used to infer past climatic and oceanographic conditions. The planktic foraminifera species Dento...

The evolution and resulting morphology of a contourite drift system in the SE Pacific oceanic basin is investigated in detail using seismic imaging and an age-calibrated borehole section. The Nazca Drift System covers an area of 204 500 km ² and stands above the abyssal basins of Peru and Chile. The drift is spread along the Nazca Ridge in water de...

Volume-dependent magnetic susceptibility (κ) is commonly used for paleoenvironmental reconstructions in both terrestrial and marine sedimentary environments where it reflects a mixed signal between primary deposition and secondary diagenesis. In the marine environment, κ is strongly influenced by the abundance of ferrimagnetic minerals regulated by...

The geological history of the South Asian monsoon (SAM) before the Pleistocene is not well‐constrained, primarily due to a lack of available continuous sediment archives. Previous studies have noted an intensification of SAM precipitation and atmospheric circulation during the middle Miocene (∼14 Ma), but no records are available to test how the mo...

The late Miocene was a period of declining CO2 levels and extensive environmental changes, which likely had a large impact on monsoon strength as well as on the weathering and erosion intensity in the South Asian Monsoon domain. To improve our understanding of these feedback systems, detrital clays from the southern Bay of Bengal (International Oce...

Abstract Arising from the non‐uniform dispersal of sediment and water that build deltaic landscapes, morphological change is a fundamental characteristic of river delta behavior. Thus, sustainable deltas require mobility of their channel networks and attendant shifts in landforms. Both behaviors can be misrepresented as degradation, particularly in...

Due to increasing water use, diversion and salinization, along with subsidence and sea-level rise, deltas in arid regions are shrinking worldwide. Some of the most ecologically important arid deltas include the Colorado, Indus, Nile, and Tigris-Euphrates. The primary stressors vary globally, but these deltas are threatened by increased salinization...

The Black Sea underwent dramatic changes in salinity from the last glacial maximum to Holocene as it evolved from a large inland lake to become a part of the global ocean due to post-glacial sea level rise. However, the detailed history of the re-connection of the Black Sea to the Mediterranean and the resulting Black Sea salinity variations have b...

South Asian precipitation amount and extreme variability are predicted to increase due to thermodynamic effects of increased 21st-century greenhouse gases, accompanied by an increased supply of moisture from the southern hemisphere Indian Ocean. We reconstructed South Asian summer monsoon precipitation and runoff into the Bay of Bengal to assess th...

The world-renowned Miocene Clarkia paleolake in northern Idaho (USA) is closely associated with Columbia River Basalt Group volcanism. The flood basalt dammed a local drainage system to form the paleolake, which preserved a plant fossil Lagerstätte in its deposits. However, the precise age and temporal duration of the lake remain unsettled. We pres...

The Arctic is undergoing accelerated changes in response to ongoing modifications to the climate system, and there is a need for local to regional scale records of past climate variability in order to put these changes into context. The Mackenzie Delta region in northern Canada is populated by numerous small shallow lakes. They are classified as no...

We carried out sedimentological and mineral magnetic studies on a ∼60 m long core recovered from the central part of the Great Rann of Kachchh (GRK), a marginal marine basin, located on the western continental margin of India to understand the Holocene paleoenvironmental changes. We critically analysed the sedimentation pattern, sediment characteri...

Tectonics and regional monsoon strength control weathering and erosion regimes of the watersheds feeding into the Bay of Bengal, which are important contributors to global climate evolution via carbon cycle feedbacks. The detailed mechanisms controlling the input of terrigenous clay to the Bay of Bengal on tectonic to orbital timescales are, howeve...

Significance Terrestrial organic-carbon reservoirs (vegetation, soils) currently consume more than a third of anthropogenic carbon emitted to the atmosphere, but the response of this “terrestrial sink” to future climate change is widely debated. Rivers export organic carbon sourced over their watersheds, offering an opportunity to assess controls o...

The neodymium isotopic composition of the detrital (lithogenic) fraction (εNd‐detrital) of surface sediments and sinking particles was examined to constrain transport trajectories associated with hemipelagic sedimentation on the northwest Atlantic margin. The provenance of resuspended sediments and modes of lateral transport in the water column wer...

The expansion of C4 vegetation during the Neogene was one of the largest reorganizations of Earth's terrestrial biome. Once thought to be globally synchronous in the late Miocene, site-specific studies have revealed differences in the timing of the expansion and suggest that local conditions play a substantial role. Here, we examine the expansion o...

During the middle Miocene, Earth's climate changed from a global warm period (Miocene Climatic Optimum) into a colder one with the expansion of the Antarctic ice sheet. This prominent climate transition was also a period of drastic changes in global atmospheric circulation. The development of the South Asian monsoon is not well understood and mainl...

The vertical distribution of subseafloor archaeal communities is thought to be primarily controlled by in situ conditions in sediments such as the availability of electron acceptors and donors, although sharp community shifts have also been observed at lithological boundaries suggesting that at least a subset of vertically stratified Archaea form a...

X-ray fluorescence (XRF) scanning of marine sediment has the potential to yield near-continuous and high-resolution records of elemental abundances, which are often interpreted as proxies for paleoceanographic processes over different time scales. However, many other variables also affect scanning XRF measurements and convolute the quantitative cal...

Humans have been present in the Andes since about 12,000 calibrated years before present (cal yr BP), transitioning from hunter-gatherers to agropastoralist societies in the mid-Holocene. Yet, the timing and effects of this change in behavior on the ecosystem are largely unknown. Using titanium from XRF analysis, loss-on-ignition (LOI), fossil poll...

Conference abstract for Goldschmidt 2020

Floods and droughts in the Mississippi River basin are perennial hazards that cause severe economic disruption. Here we develop and analyze a new lipid biomarker record from Horseshoe Lake (Illinois, USA) to evaluate the climatic conditions associated with hydroclimatic extremes that occurred in this region over the last 1,800 years. We present geo...

Valves of a thoracican cirripede belonging to a new species of the Neolepadidae, Ashinkailepas indica Gale sp. nov. are described from a Late Pleistocene cold seep (52.6 ka), cored in the Krishna-Godavari Basin, offshore from the eastern coast of India. This constitutes the first fossil record of the genus, and its first occurrence in the Indian Oc...

Abstract. The expansion of C₄ vegetation during the Neogene was one of the largest reorganizations of Earth's terrestrial biome. Once thought to be globally synchronous in the late Miocene, site-specific studies have revealed differences in the timing of the expansion and suggest that local conditions play a substantial role. Here, we ex...

X‐ray fluorescence (XRF) core scanning of marine and lake sediments has been extensively used to study changes in past environmental and climatic processes over a range of timescales. The interpretation of XRF‐derived element ratios in paleoclimatic and paleoceanographic studies primarily considers differences in the relative abundances of particul...

Offshore archives retrieved from marine/lacustrine environments receiving sediment from large river systems are valuable Quaternary continental records. In the present study, we reconstruct the Danube River activity at the end of the last glacial period based on sedimentological, mineralogical and geochemical analyses performed on long-piston cores...

High-resolution pollen analyses were performed on two cores from the western Black Sea and one core from the Marmara Sea, covering the Late Glacial-Holocene transition using 14C chronology. Particular effort was invested in the botanical identification of pollen grains thereby significantly improving our knowledge of regional flora. When interprete...

The evolution and resulting morphology of a contourite drift system in the SE Pacific oceanic basin is investigated in unprecedented detail using seismic imaging and an age-calibrated section. The Nazca Drift System covers an area of 204,500 km² and stands above the abyssal basins of Peru and Chile. It lies in water between 2,090 and 5,330 m deep,...

The hazards posed by infrequent major floods to communities along the Susquehanna River and the ecological health of Chesapeake Bay remain largely unconstrained due to the short length of streamgage records. Here we develop a history of high-flow events on the Susquehanna River during the late Holocene from flood deposits contained in MD99-2209, a...

We reconstruct the provenance of aluminosilicate sediment deposited in Ulleung Basin, Japan Sea, over the last 12 Ma at Site U1430 drilled during Integrated Ocean Drilling Program Expedition 346. Using multivariate partitioning techniques (Q-mode factor analysis, multiple linear regressions) applied to the major, trace and rare earth element compos...

We reconstruct the provenance of aluminosilicate sediment deposited in Ulleung Basin, Japan Sea, over the last 12 Ma at Site U1430 drilled during Integrated Ocean Drilling Program Expedition 346. Using multivariate partitioning techniques (Q-mode factor analysis, multiple linear regressions) applied to the major, trace and rare earth element compos...

Spectral analysis of sediment from International Ocean Discovery Program (IODP) Site U1433 in the South China Sea can be used to constrain humidity and temperature through time by constructing hematite/goethite records spanning the last 10 million years. Records in the southwest and northern parts of this basin show long-term contrasting trends, de...

Subsurface microbial communities are generally thought to be structured through in situ environmental conditions such as the availability of electron acceptors and donors and porosity, but recent studies suggest that the vertical distribution of a subset of subseafloor microbial taxa, which were present at the time of deposition, were selected by t...

Radiogenic isotopes of strontium ( ⁸⁷ Sr/ ⁸⁶ Sr) and neodymium ( ¹⁴⁴ Nd/ ¹⁴³ Nd) are widely used to trace sediment across source-to-sink networks, with samples typically collected from outcrops at basin headwaters and from sediments along the channel margin, floodplain, and/or seafloor. Here, we established the Sr-Nd isotope systematics of recent (...

Constraining radiocarbon ( ¹⁴ C) reservoir age offsets is critical to deriving accurate calendar-age chronologies from ¹⁴ C dating of materials which did not draw carbon directly from the atmosphere. The application of ¹⁴ C dating to such materials is severely limited in hydrologically sensitive environments like the Black Sea because of the diffic...

A new fossil pollen, Sporormiella, and sediment chemistry record from Lake Llaviucu, Ecuador, spanning the period from 16,280–9000 years Before Present, provides a high-resolution record of paleoecological change in the high Andes. The deglacial transition from super-páramo through páramo grasslands, to Andean forest is traced, with near-modern sys...

Deltas are the most productive and economically important global ecosystems, associated with some of the largest coastal marine fisheries and the majority of global coastal wetlands. They are often regions of intense economic activity. Because of their ecological richness, deltas support the highest values of ecosystem goods and services in the wor...

The Indus valley (or Harappan) civilisation is known to have experienced significant deterioration after around 2000 bc when many of the major urban centres were abandoned. This societal decay has been linked to a drying of the climate at the same time, when lakes in the Rajasthan area contracted and dried up, and discharge from the River Indus red...

Climate exerted constraints on the growth and decline of past human societies but our knowledge of temporal and spatial climatic patterns is often too restricted to address causal connections. At a global scale, the inter-hemispheric thermal balance provides an emergent framework for understanding regional Holocene climate variability. As the therm...

The orbital-scale timing of South Asian monsoon (SAM) precipitation is poorly understood. Here we present new SST and seawater δ¹⁸O (δ¹⁸Osw) records from the Bay of Bengal, the core convective region of the South Asian monsoon, over the past 1 million years. Our records reveal that SAM precipitation peaked in the precession band ~9 kyrs after North...

Western India has witnessed significant variability during the late Quaternary in the paleohydrology (monsoon intensity, droughts), tectonic episodes, sea-level changes and overall landscape architecture. Marginal marine basins such as Gulf of Kachchh, Gulf of Cambay, Ranns of Kachchh (Little and Great Rann of Kachchh) archived signatures of these...

Relatively little is known about the amount of time that lapses between the photosynthetic fixation of carbon by vascular land plants and its incorporation into the marine sedimentary record, yet the dynamics of terrestrial carbon sequestration have important implications for the carbon cycle. Vascular plant carbon may encounter multiple potential...

Sediment supply and sea level interact to control sediment flux to deep-water submarine fans. Although some fans continue to be active during times of rising sea level, the source of sediment is not always clear and may be dominated by reworking in high energy coastal areas rather than reflecting erosional signals directly from the source drainage...

We performed a detrital zircon (DZ) U-Pb geochronologic survey of the lower parts of the Danube River approaching its Danube delta- Black Sea sink, and a few large tributaries (Tisza, Jiu, Olt and Siret) originating in the nearby Carpathian Mountains. Samples are modern sediments. DZ age spectra reflect the geology and specifically the crustal age...

A period of cooling about 13,000 years ago interrupted about 2,000 years of deglacial warming. Known as the Younger Dryas (YD), the event is thought to have resulted from a slowdown of the Atlantic meridional overturning circulation in response to a sudden flood of Laurentide Ice Sheet meltwater that reached the Nordic Seas. Oxygen isotope evidence...

An extensive oxygen minimum zone (OMZ) occurs in the northeastern (NE) Arabian Sea where sedimentary records show evidence of alternating strong and weak OMZs that correlate with North Atlantic climate variability during the last glacial–interglacial cycle. OMZs are expanding world-wide, but information on long-term OMZ-ecosystem interactions is ma...

The Ayeyawady delta is the last Asian megadelta whose evolution has remained essentially unexplored so far. Unlike most other deltas across the world, the Ayeyawady has not yet been affected by dam construction, providing a unique view on largely natural deltaic processes benefiting from abundant sediment loads affected by tectonics and monsoon hyd...

The modern-day Godavari River transports large amounts of sediment (170 Tg per year) and terrestrial organic carbon (OCterr; 1.5 Tg per year) from peninsular India to the Bay of Bengal. The flux and nature of OCterr is considered to have varied in response to past climate and human forcing. In order to delineate the provenance and nature of organic...

Fluvial export of organic carbon (OC) and burial in ocean sediments comprises an important carbon sink, but fluxes remain poorly constrained, particularly for specific organic components. Here OC and lipid biomarker contents and isotopic characteristics of suspended matter determined in depth profiles across an active channel close to the terminus...

We examine the paleoceanographic record over the last ∼400 kyr derived from major, trace, and rare earth elements in bulk sediment from two sites in the East China Sea drilled during Integrated Ocean Drilling Program Expedition 346. We use multivariate statistical partitioning techniques (Q-mode factor analysis, multiple linear regression) to ident...

Climate exerted constraints on the growth and decline of past human societies but our knowledge of temporal and spatial climatic patterns is often too restricted to address causal connections. At a global scale, the inter-hemispheric thermal balance provides an emergent framework for understanding regional Holocene climate variability. As the therm...

The Quaternary hemipelagic sediments of the Japan Sea are characterized by centimeter-to decimeter-scale alternation of dark and light clay to silty clay, which are bio-siliceous and/or bio-calcareous to a various degree. Each of the dark and light layers are considered as deposited synchronously throughout the deeper (> 500 m) part of the sea. How...

The modern-day Godavari River transports large amounts of sediment (170 Tg per year) and terrestrial organic carbon (OCterr; 1.5 Tg per year) from peninsular India to the Bay of Bengal. The flux and nature of OCterr is considered to have varied in response to past climate and human forcing. In order to delineate the provenance and nature of organic...

Soil erosion plays a crucial role in transferring sediment and carbon from land to sea, yet little is known about the rhythm and rates of soil erosion prior to the most recent few centuries. Here we reconstruct a Holocene erosional history from central India, as integrated by the Godavari River in a sediment core from the Bay of Bengal. We quantify...

Understanding the transport history and fate of organic carbon (OC) within river systems is crucial in order to constrain the dynamics and significance of land–ocean interactions as a component of the global carbon cycle. Fluvial export and burial of terrestrial OC in marine sediments influences atmospheric CO2 over a range of timescales, while riv...

The Ayeyawady delta is the last Asian megadelta whose evolution has remained essentially unexplored so far. Unlike most other deltas across the world, the Ayeyawady has not yet been affected by dam construction providing a unique view on largely natural deltaic processes benefiting from abundant sediment loads affected by tectonics and monsoon hydr...

The distinctive plan-view shape of the Ebro Delta coast reveals a rich morphologic history. The degree to which the form and depositional history of the Ebro and other deltas represent autogenic (internal) dynamics or allogenic (external) forcing remains a prominent challenge for paleo-environmental reconstructions. Here we use simple coastal and f...

In natural conditions marginal deltaic coasts benefit from sediment input from upcoast deltas via longshore drift and current-driven transport. This study investigated changes in the pattern and variability of both the shoreline and nearshore zone along the southern Romanian coast located downdrift of the Danube delta. We employed modern and histor...

Selection of microorganisms in marine sediment is shaped by energy-yielding electron acceptors for respiration that are depleted in vertical succession. However, some taxa have been reported to reflect past depositional conditions suggesting they have experienced weak selection after burial. In sediments underlying the Arabian Sea oxygen minimum zo...