Martin Koelling

Universität Bremen | Uni Bremen · MARUM - Center for Marine Environmental Sciences

Mud volcanoes (MVs) are surface structures typically created by episodic discharge of fluids and solids, often associated to onshore and offshore accretionary prisms on convergent plate boundaries. Detailed investigations of ongoing activity and its associated morphological changes, as well as a better understanding of the temporal evolution of the...

Hadal trenches are unique geological and ecological systems located along subduction zones. Earthquake-triggered turbidites act as efficient transport pathways of organic carbon (OC), yet remineralization and transformation of OC in these systems are not comprehensively understood. Here we measure concentrations and stable- and radiocarbon isotope...

Petrography of recrystallised ikaite from Ocean Drilling Program material has been presented previously from Nankai Trough and Congo (ex-Zaire) deep-sea fan. This paper expands on the Nankai Trough ikaite observations, drawing on evidence from Laptev Sea, South Georgia, Okhotsk Sea, and coastal lagoon Point Barrow. However, even though many ikaite...

In the past 20 years, the exploration of deep ocean trenches has led to spectacular new insights. Even in the deepest canyons, an unusual variety of life and unexpectedly high benthic oxygen consumption rates have been detected while microbial processing below the surface of the hadal seafloor remains largely unknown. The information that exist com...

This preprint has been submitted to AGU's journal Geochemistry, Geophysics, Geosystems (G-Cubed). ESSOAr is a venue for early communication or feedback before peer review. The discussion and interpretation of the unique data set of sediment and pore water date may be preliminary.

In order to obtain a better knowledge of oceanic changes in the Canary Upwelling region during the Late Holocene, marine surface samples and two sediment cores retrieved off southwestern Morocco, GeoB8601–3 and GeoB4223–1, were investigated for organic-walled dinoflagellate cysts (dinocysts). The results were compared with pollen, microcharcoal par...

he southwest of Morocco is considered to be an area of refuge within the Mediterranean region, hosting the endemic tropical Argan tree. This region is presently subject to severe droughts, desertification and land degradation, and likely facing increased climate variability and socio-economic stress in the future. Here, we use the stable hydrogen a...

The evolution of submarine pockmarks is often related to the ascent of fluid from the subsurface. For pockmarks located within the gas hydrate stability zone, methane oversaturation can result in the formation of gas hydrates in the sediment. An ~600 m‐wide sea floor depression in deep waters offshore Nigeria, Pockmark A, was investigated for distr...

Methane is abundant in marine subsurface sediments, sourced from microbial or thermocatalytic products. The relative composition of its isotopologues (12CH4, 13CH4, 12CH3D and 13CH3D) is used to infer its sources and sinks. The anaerobic oxidation of methane (AOM) is an important methane sink reaction carried out by consortia of anaerobic methanotr...

We report on the geochemistry of light hydrocarbons and pore water in sediments down to 147 m below seafloor (mbsf), at two sites within the gas hydrate stability field of the Danube deep-sea fan, Black Sea. Sediments were drilled with MARUM-MeBo200 and comprise the transition from limnic to the recent marine stage. Stable C/N ratios (<5.7) and δ¹³...

Previous evidence suggests enhanced pyrite oxidation on exposed continental shelves during glacial phases of low sea level. While pyrite oxidation directly consumes atmospheric oxygen, acid generated by this reaction should increase the release of CO2 through carbonate dissolution. This scenario represents a climate control loop that could temper o...

Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the...

"Cover of the Science Mag" Lyrics & performance: M.Kölling Performed at the Paleomusicology night of the ICP13 at the Sir John Clancy Auditorium UNSW, Sydney. on Sep 5, 2019. Link to video from ICP13: https://youtu.be/Ph7-zk6pf6k Paleomusicology version of "Cover of the Rolling Stone" by Dr. Hook & the Medicine Show, written by Shel Silverstein,...

Morocco is an area subject to recurrent severe droughts, desertification and an increasing land degradation. It is within a Mediterranean hotspot of biodiversity as it harbors many threatened endemic species such as the argan tree (Argania spinosa). In this context, past climate records are needed to analyze the impact of climate variability on the...

Submarine groundwater discharge; Nutrients; French Polynesia; Tahiti; Moorea; Volcanic islands; Nitrogen and oxygen isotope ratios of nitrate

Submarine fresh groundwater discharge (SFGD) provides a pathway for dissolved nutrients and other solutes from land to the ocean. It connects pollution from anthropogenic land use with coastal marine waters. In case of the oligotrophic central South Pacific Ocean around Tahiti and Moorea, French Polynesia, nutrient concentrations are particularly l...

The climate of the Sahara and Arabian Deserts during the Little Ice Age is not well known, due to a lack of annually resolved natural and documentary archives. We present an annual reconstruction of temperature and aridity derived from Sr/Ca and oxygen isotopes in a coral of the desert‐surrounded northern Red Sea. Our data indicate that the eastern...

The Rare Earth Elements (REEs) have been widely used to investigate marine biogeochemical processes as well as the sources and mixing of water masses. However, there are still important uncertainties about the global aqueous REE cycle with respect to the contributions of highly reactive basaltic minerals originating from volcanic islands and the ro...

The seasonality of hydroclimate during past periods of warmer than modern global temperatures is a critical component for understanding future climate change scenarios. Although partially analogous to these scenarios, the last interglacial (LIG, Marine Isotope Stage 5e, ~127-117 ka) is a popular test-bed. We present coral δ18O monthly resolved reco...

Explanations of the Classic Maya civilization demise on the Yucatán Peninsula during the Terminal Classic Period (TCP; ~CE 750-1050) are controversial. Multiyear droughts are one likely cause, but the role of the Caribbean Sea, the dominant moisture source for Mesoamerica, remains largely unknown. Here we present bimonthly-resolved snapshots of rec...

To assess the reliability of turbidite paleoseismology, it is crucial to precisely understand and characterize the processes, in which earthquake shaking initiates sediment remobilization, transport and eventually deposition. In most studies, it is assumed that strong earthquakes trigger landslides on the slopes and the moving masses transform into...

Growth curve and phosphate uptake measured in the Roseobacter cultures. Cell density (triangles) and phosphate concentrations (circles) over time in cultures grown under +Pi (empty symbols) and ?P (filled symbols) conditions. (A) Phaeobacter inhibens strain DSM-17395; (B) Phaeobacter inhibens strain DSM-16374; (C) Ruegeria pomeroyi strain DSM-15171...

Schematic overview of the cultivation experiments performed with Pseudovibrio sp. strain FO-BEG1. (A) Description of the original cultivation experiments performed using CM medium amended with an acidified trace element solution. (B) In the refresh experiment, cells were pre-grown under ?Pi conditions, until the previously detected maximum Fe uptak...

Phosphorus is an essential nutrient for all living organisms. In bacteria, the preferential phosphorus source is phosphate, which is often a limiting macronutrient in many areas of the ocean. The geochemical cycle of phosphorus is strongly interconnected with the cycles of other elements and especially iron, because phosphate tends to adsorb onto i...

Reconstructions of last interglacial (LIG, MIS 5e, ∼127–117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. We present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire (Caribbean...

Otoliths of Atlantic bluefin tuna (Thunnus thynnus) collected from the Mediterranean Sea and North Atlantic Ocean were analyzed to evaluate changes in the seawater isotopic composition over time. We report an annual otolith delta C-13 record that documents the magnitude of the delta C-13 depletion in the Mediterranean Sea between 1989 and 2010. Atl...

Reconstructions of last interglacial (LIG, MIS 5e, ~127-117 ka) climate offer insights into the natural response and variability of the climate system during a period partially analogous to future climate change scenarios. We present well preserved fossil corals (Diploria strigosa) recovered from the southern Caribbean island of Bonaire (Caribbean...

Sampling a series of Glycymeris species shells from an age transect in the well-dated Gatas excavation site, we found δ18O isotope ratios that indicate a small gradual decrease in mean sea surface temperatures between 27oo BC and 12oo BC. The sea surface temperature seasonality recorded in the mollusk shells during this period was 7.o °C. While the...

SEALEX model run as mp4 movie clip

The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an impo...

The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an impo...

Several studies indicate that the 2011 Tohoku-Oki earthquake (Mw 9.0) off the Pacific coast of Japan has induced slip to the trench and triggered landslides in the Japan Trench. In order to better understand these processes, detailed mapping and shallow-coring landslides at the trench as well as Integrated Ocean Drilling Program (IODP) deep drillin...

The Sr/Ca ratio of coral aragonite is used to reconstruct past sea surface temperature (SST). Twenty-one laboratories took part in an interlaboratory study of coral Sr/Ca measurements. Results show interlaboratory bias can be significant, and in the extreme case could result in a range in SST estimates of 7° C. However, most of the data fall within...

We present differential bathymetry and sediment core data from the Japan Trench, sampled after the 2011 Tohoku-Oki (offshore Japan) earthquake to document that prominent bathymetric and structural changes along the trench axis relate to a large (∼27.7 km2) slump in the trench. Transient geochemical signals in the slump deposit and analysis of diffu...

A range of future climate scenarios have been predicted for a warmer Earth as a result of varying anthropogenic greenhouse emissions. The Last Interglacial period (~125,000 years ago, Marine Isotope Stage 5) offers a period in time which is estimated to have been in the range of 0.1 to > 2oC warmer than present (AD 1961-1990). Although this period...

In the tropical Atlantic, proxy reconstructions of Holocene sea surface temperature and salinity that resolve seasonality and interannual to decadal variability are sparse. However, ocean-atmosphere interactions on these timescales play a critical role for climate extremes such as droughts, floods and hurricanes. Consequently, a better understandin...

Several proxy-based and modeling studies have investigated long-term changes in Caribbean climate during the Holocene, however, very little is known on its variability on short timescales. Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca...

The Japan Trench subduction zone has repeatedly been affected by large earthquakes as most recently in 2011 by the giant magnitude 9 Tohoku-Oki earthquake. Several studies indicate that the 2011 earthquake has induced large seafloor displacements and triggered submarine landslides and gravity flows. The depression of the Japan Trench floor acts as...

Several proxy-based and modeling studies have investigated long-term changes in Caribbean climate during the Holocene, however, very little is known on its variability on short timescales. Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca...

Here we reconstruct seasonality and interannual to multidecadal variability of sea surface hydrology of the southern Caribbean Sea by applying paired coral Sr/Ca and δ¹⁸O measurements on fossil annually-banded Diploria strigosa corals from Bonaire. This allows for better understanding short-term (i.e., seasonal to multidecadal) variabili...

The early last glacial termination was characterized by intense North Atlantic cooling and weak overturning circulation. This interval between ~18,000 and 14,600 years ago, known as Heinrich Stadial 1, was accompanied by a disruption of global climate and has been suggested as a key factor for the termination. However, the response of interannual c...

Proxy reconstructions of tropical Atlantic sea surface temperature (SST) that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability. Here we present monthly-resolved records of Sr/Ca (a proxy of SST) from fossil annually-banded Diplori...

We present a unique collection of annually banded fossil Montastraea coral colonies from Bonaire (Netherlands Antilles) in the southern Caribbean Sea that reveals growth between ~AD 800-1050. Coincidentally, this time interval was known for the demise of the classic Maya civilization in the lowlands of the Yucatán Peninsula termed the Terminal Clas...

The northern Red Sea represents a unique location where ocean currents transport warm tropical waters northward, enabling coral reef growth at unusually high latitudes of up to 29 °N. Moreover, one of the world's northernmost complexes of uplifted Pleistocene reef terraces can be found here at Aqaba (Jordan). We present sub-seasonally resolved reco...

Proxy reconstructions of tropical Atlantic sea surface temperature (SST) that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability. Here we present monthly-resolved records of Sr/Ca (a proxy of SST) from fossil annually-banded Diplori...

The early last glacial termination was characterized by intense North Atlantic cooling and weak overturning circulation. This interval between ~18,000 and 14,600 years ago, known as Heinrich Stadial 1, was accompanied by a disruption of global climate and has been suggested as a key factor for the termination. However, the response of interannual c...

In the western tropical Atlantic, paleoceanographic reconstructions that robustly resolve seasonality and interannual to interdecadal variability beyond the short period of instrumental observations are extremely rare. Ocean-atmosphere interactions on these timescales play a critical role for society-relevant climate extremes such as droughts, floo...

Coral Sr/Ca-based reconstructions have revealed a larger amplitude of sea surface temperature (SST) changes throughout the last deglaciation relative to foraminiferal Mg/Ca and alkenone-based SST reconstructions in the tropical Atlantic and the tropical southwestern Pacific. Here we present new coral Sr/Ca records from Tahiti in the central tropica...

Mg/Ca ratios of surface and subsurface dwelling foraminifera provide valuable information about the past temperature of the water column. Planktonic foraminifera calcify over a period of weeks to months. Therefore, the range of Mg/Ca temperatures obtained from single specimens potentially records seasonal temperature changes. We present solution-de...

The data shows Mg/Ca ratios of single specimens of the planktonic foraminifera Globigerinoides ruber (pink and white variety) and Globorotalia Inflata from a sediment trap anchored off Cape Blanc (NW-Africa). Mg/Ca ratios were determined on an ICP-MS and ICP-OES at the University of Bremen, after flow-through cleaning. Additionally, shells sizes an...

Geochemical tracers incorporated into the skeleton of reef-building corals are ideal proxies for reconstructing environmental parameters of ambient seawater such as temperature and salinity at subseasonal resolution. However, validation concerns of these environmental proxies due to the complex skeleton of some tropical Atlantic corals have hindere...

We present Mg/Ca analyses performed via a Flow Through sequential dissolution device connected to an ICP-OES on the planktonic foraminifer Globorotalia inflata. The aim of the study is to explore the possibility to reconstruct the thermal gradient in the water column by separating non-crusted and crusted calcite phases in the tests of G. inflata us...

Chemostratigraphy has been applied to three cores within the Dakar Canyon System offshore NW Africa using the geochemical element data of the sediment successions in order to distinguish and correlate their turbidite sequences. This modern submarine canyon system has been studied using joint sedimentological, geophysical and geochemical approaches...

Geochemical tracers incorporated into the skeleton of reef-building corals are ideal proxies for reconstructing environmental parameters of ambient seawater such as temperature and salinity at subseasonal resolution. However, validation concerns of these environmental proxies due to the complex skeleton of some tropical Atlantic corals have hindere...

Assessing the response of interannual climate variability in the tropical Pacific Ocean to future greenhouse warming is of paramount importance. However, the dominant mode of Pacific atmosphere-ocean variability on interannual timescales, the El Niño-Southern Oscillation (ENSO), is poorly understood with respect to its behaviour under boundary cond...

We analyzed a suite of sediment samples recovered in the central Arctic Ocean for major, trace, and rare earth elements in order to assess changes in terrigenous source material throughout the Cenozoic. The terrigenous component consists of two end-members. Input from a shale-like composition dominates bulk sediments, especially those deposited dur...

The response of interannual climate variability in the tropical Pacific Ocean to future greenhouse warming plays a crucial role in climate model simulations. However, the dominant mode of Pacific atmosphere-ocean variability on interannual timescales, the El Niño-Southern Oscillation (ENSO), is poorly understood with respect to its behaviour under...

The Integrated Ocean Drilling Program's Expedition 302, the Arctic Coring Expedition (ACEX), recovered the first Cenozoic sedimentary sequence from the central Arctic Ocean. ACEX provided ground truth for basin scale geophysical interpretations and for guiding future exploration targets in this largely unexplored ocean basin. Here, we present resul...

A reef growth model has been developed using an Excel spreadsheet. The 1D forward model is driven by a user definable sea-level curve. Other adjustable model parameters include maximum coral growth rate, coral growth rate depth dependence and light attenuation, subaerial erosion and subsidence. A time lag for the establishment of significant reef a...

We analyzed a suite of sediment samples recovered in the central Arctic Ocean for major, trace, and rare earth elements in order to assess changes in terrigenous source material throughout the Cenozoic. The terrigenous component consists of two end-members. Input from a shale-like composition dominates bulk sediments, especially those deposited dur...

We have analyzed sediments from Integrated Ocean Drilling Program Arctic Coring Expedition 302 in the central Arctic Ocean, for major, trace, and rare earth elements in order to assess detrital source changes to the Lomonosov Ridge throughout the Cenozoic. The terrigenous component consists of two compositional end- members, one with a shale-like c...

Age models for the emplacement time of mass flow deposits from the Cape Blanc Debris Flow, the Mauritania Slide Complex and a levee of the Mauritania Canyon were obtained by offshore X-ray fluorescence (XRF) element stratigraphy on five gravity cores, allowing the assessment of slope instability in this part of the NW African continental margin wit...

IntroductionData Basis for Model DevelopmentThe Model (DiffMod7) Model Concept Diffusive TransportPyrite WeatheringConvective TransportComputer Implementation of Model and User InterfaceExampleModelling Column ExperimentsRunning ScenariosField TestDiscussionSummaryReferences Model Concept Diffusive TransportPyrite WeatheringConvective TransportComp...

No abstract available. doi:10.2204/iodp.sd.4.08.2007

For more than 35 years, interstitial water (IW) samples have been collected from sediment recovered during marine scientific coring expeditions. Pioneering work of DSDP and ODP quickly demonstrated that pore water chemistry differed from that of overlying seawater and from one location to another for myriad reasons (Sayles and Manheim, 1975). Extra...