George A Wolff

University of Liverpool | UoL · School of Environmental Sciences

Using the non-invasive aquatic eddy covariance technique, we provide the first oxygen (O 2 ) uptake rates from within coral gardens at the Condor seamount (Azores). To explore some of the key drivers of the benthic O 2 demand, we obtained benthic images, quantified local hydrodynamics, and estimated phototrophic biomass and deposition dynamics with...

Presence of various types of hydrocarbons in all the studied sample locations in the Western Alps (Chenaillet unit) and Central Alps (Totalp, Tasna and Platta units). The main hydrocarbon types found in the rocks of the fossil Tethyan OCT are n -alkanes, from C 16 to C 32 , low molecular weight polynuclear aromatic hydrocarbons (PAHs), hopanes, ste...

Serpentinisation and concomitant reduction of CO2 to methane at modern hydrothermal vents has been observed to support methanotrophic biosystems at mid-ocean ridges. Exhumation of mantle within ocean regions and its subsequent serpentinisation is a common occurrence. It is possible that methanotrophy is not restricted to hydrothermal vents systems...

Deep-sea benthic communities depend on the export of organic matter (OM) from the surface ocean. However, the effects of the pelagic-benthic coupling and the specific link between changing seasonal OM inputs and physiological changes of the mega-benthic community remain unclear. In this study, we identified differences in OM quality and quantity at...

Ambrein is found in ambergris, a coprolith occurring in the rectum of the sperm whale. In vitro, ambrein is produced by enzymatic cyclisation of squalene, via a monocyclic intermediate. However, little is known of the in vivo process. In order to find evidence for the reaction in vivo, a comparison was made of the δ¹³C relative isotopic ratios of a...

A fraction of organic carbon produced in the oceans by phytoplankton sinks storing 5‐15 gigatonnes of carbon annually in the ocean interior. The accepted paradigm is that rapid aggregation of phytoplankton cells occurs forming large, fresh particles which sink quickly; this concept is incorporated into ecosystem models used to predict the future cl...

Paq proxy was applied on mid and long-chain n-alkanes in order to develop an index to assist in the long-term assessment of changes and exchanges between aquatic communities in estuarine environments as a result of increased saline incursion. New boundaries are proposed according to n-alkanes abundance in the leaves of local mangrove tree species f...

Natural iron fertilization downstream of Southern Ocean island plateaus supports large phytoplankton blooms and promotes carbon export from the mixed layer. In addition to sequestering atmospheric CO2, the biological carbon pump also supplies organic matter (OM) to deep-ocean ecosystems. Although the total flux of OM arriving at the seafloor sets t...

Organic matter (OM) plays an important role in productive shelf seas and their contribution to global carbon (C) and nutrient cycles. We investigated dissolved and particulate OM (DOM and POM, respectively) dynamics over a seasonal cycle in the Celtic Sea. The quantity of OC was largest during the spring bloom and lowest in autumn. DOM was always C...

The impact of past global climate change on local terrestrial ecosystems and their vegetation and soil organic matter (OM) pools is often non-linear and poorly constrained. To address this, we investigated the response of a temperate habitat influenced by global climate change in a key glacial refuge, Lake Ohrid (Albania, Macedonia). We applied ind...

Natural iron fertilization downstream of Southern Ocean island plateaus support large phytoplankton blooms and promote carbon export from the mixed layer. In addition to sequestering atmospheric CO2, the biological carbon pump also supplies organic matter (OM) to deep-ocean ecosystems. Although the total flux of OM arriving at the seafloor sets the...

This study reviews and synthesises existing information generated within the SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) deep drilling project. The four main aims of the project are to infer (i) the age and origin of Lake Ohrid (Former Yugoslav Republic of Macedonia/Republic of Albania), (ii) its regional seismote...

Evidence from ultraslow spreading mid-ocean ridges and both fossil and present-day Ocean–Continent Transitions (OCT) demonstrates that mantle serpentinization resulting from the interaction of mantle rock and water during tectonic exhumation is widespread. Observations at white smokers in modern ocean settings suggest that methane produced by serpe...

As tall seamounts may be ‘stepping stones’ for dispersion and migration of deep open ocean fauna, an improved understanding of the productivity at and food supply to such systems needs to be formed. Here, the ²³⁴Th/²³⁸U approach for tracing settling particulate matter was applied to Senghor Seamount --- a tall sub-marine mountain near the tropical...

Sinking particulate organic matter (POM, phytodetritus) is the principal limiting resource for deep-sea life. However, little is known about spatial variation in POM supply to the abyssal seafloor, which is frequently assumed to be homogenous. In reality, the abyss has a highly complex landscape with millions of hills and mountains. Here, we show a...

The ocean's biological carbon pump plays a central role in regulating atmospheric CO2 levels. In particular, the depth at which sinking organic carbon is broken down and respired in the mesopelagic zone is critical, with deeper remineralization resulting in greater carbon storage. Until recently, however, a balanced budget of the supply and consump...

The ocean’s biological carbon pump plays a central role in regulating atmospheric CO2 levels. In particular, the depth at which sinking organic carbon is broken down and respired in the mesopelagic zone is critical, with deeper remineralisation resulting in greater carbon storage. Until recently, however, a balanced budget of the supply and consump...

We investigated sediments from a piston core (site Co1202) in the northeastern part of Lake Ohrid (Macedonia, Albania) that cover the period from 136 to 97 ka, i.e. most of marine isotope stage (MIS) 5 including Termination II and the peak warm period of MIS 5e (Eemian). The aim of the study was to reconstruct climatically controlled changes in the...

The Piraquê-Açú and Piraquê-Mirim estuarine system (PAPMES) is considered to be a hydrologically unaltered estuary; however, several human activities including introduction of pollutants may have contributed to changes in this system. We have studied hydrocarbons, major elements (Al, Mg, Fe and Mn), trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Ni, P...

We present elemental, lipid biomarker and, in the supplement, compound-specific isotope (δ13C, δ2H) data for soils and leaf litter collected in the catchment of Lake Ohrid (Albania, Macedonia), as well as macrophytes, particulate organic matter and sediments from the lake itself. Lake Ohrid provides an outstanding archive of continental environment...

Astomonema is a nematode genus belonging to the family Astomonematinae, characterized by abundant endosymbiotic chemo-autotrophic bacteria located within the body. Their dependence on these prokaryote symbionts as an energy source is obvious since these nematodes lack a mouth and their pharynx is vestigial, precluding food uptake via the mouth. Unt...

We present elemental, lipid biomarker and compound-specific isotope (δ13C, δ2H) data for soils and leaf litter collected in the catchment of Lake Ohrid (Albania, Macedonia), as well as macrophytes, particulate organic matter and sediments from the lake itself. Lake Ohrid provides an outstanding archive of continental environmental change of at leas...

The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope...

Organic matter (OM) plays an important role in productive shelf seas and their contribution to global carbon (C) and nutrient cycles. We investigated the impact of storm mixing on OM dynamics in the seasonally stratified Celtic Sea. After the storm, OM production was decoupled from consumption in the euphotic layer. Over the 15-day study, dissolved...

The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope...

The production of organic carbon in the ocean’s surface and its subsequent downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown is countered by the biological precipitation of carbonate, followed by sinking of particulate inorganic carbon, which is a source of carbon dioxide to the surface ocean, and hence the atmosphere ov...

The production of organic carbon in the ocean’s surface and its subsequent downward export transfers carbon dioxide to the deep ocean. This CO2 drawdown is countered by the biological precipitation of carbonate, followed by sinking of particulate inorganic carbon, which is a source of carbon dioxide to the surface ocean, and hence the atmosphere ov...

Dissolved organic matter (DOM) is a complex array of molecules containing carbon, nitrogen and phosphorus. Much of our understanding of the vertical distribution of DOM is gleaned from permanently stratified deep ocean regions. Here, net production of DOM via passive exudation, cell lysis, grazing etc leads to an accumulation of more labile materia...

The reproductive characteristics of six ophiuroid species, Ophiura irrorata loveni, Ophiura lienosa, Amphioplus daleus, Ophiacantha cosmica, Ophiernus quadrispinus and Ophioplexa condita, were studied at two localities in the vicinity of the Crozet Islands in the Southern Indian Ocean. The two localities were notable in having almost identical envi...

The suspended particulate organic matter (sPOM) around two isolated NE Atlantic seamounts, Seine (33°46′N 14°21′W; summit at ∼170 m) and Sedlo (40°19′N 26°40′W; summit at ∼780 m), was studied over a period of 2 years during four 2–4-week oceanographic surveys. Elemental (C and N), chlorophyll a and lipid biomarker concentrations and N stable isotop...

Oxygen minimum zones (OMZs) are naturally occurring, low-oxygen water masses that create hypoxic conditions where they impinge on the seafloor. Their lower boundaries are characterised by elevated densities of hypoxia-tolerant fauna and an abundant food supply. The polychaete Linopherus sp. nov. (Amphinomidae) is the dominant taxon at the Pakistan...

Cold-water coral (CWC) reefs are recognised as an important marine benthic eco- system at continental margins. Where abundant, they most likely play a role both in the mainte- nance of biodiversity and in the provision of ecosystem services provided by shelf seas. Here, we directly measure the community respiration of a CWC reef on the Norwegian sh...

Southern Ocean Island systems sustain phytoplankton blooms induced by natural iron fertilization that are important for the uptake of atmospheric carbon dioxide and serve as analogues for past and future climate change. We present data on diatom flux assemblages and the biogeochemical properties of sinking particles to explain the enhanced particul...

During HERMES cruises in spring 2006 and 2007 to a cold- water coral (CWC) reef at the border between Norway and Sweden, we studied effects of the reef on the quality (C/N ratio) of suspended particles. The Tisler reef is situated on top of a southeast-northwest-oriented sill forming the connection between the Kosterfjord and the open Skagerrak. In...

Photograph of ISIS ROV with the SM2000 receiving transducer mounted on the front of the vehicle. (TIF)

Cold-water corals are azooxanthellate species found throughout the ocean at water depths down to 5000 m. They occur in patches, reefs or large mound structures up to 380 m high, and as ecosystem engineers create important habitats for a diverse fauna. However, the majority of these habitats are now within reach of deep-sea bottom trawling. Many hav...

The abundance, diversity and assemblage structure of polychaetes from the Nazaré, Setúbal and Cascais Canyons along the Iberian Margin were studied as part of the EU project HERMES. A Dynamic Equilibrium Model (DEM) was used to identify the main environmental factors structuring the assemblages. Box corer and megacorer samples from upper (1000 m),...

Abundance and biomass (wet weight) data for Echinoderm megafauna. Station numbers are taken from ref 19. (DOCX)

Pigment concentrations (µg gDW−1) in the ovaries of Peniagone spp. (n = 5 at each site) sampled at Crozet. 19′-but = 19′-butanoyloxyfucoxanthin; 19′-hex = 19′-hexanoyloxyfucoxanthin; Diadinox = diadinoxanthin; Allox = alloxanthin; Diatox = diatoxanthin; Zeax = zeaxanthin; Canthax = canthaxanthin; Echin = echinenone; β-carot = β-carotene. (Standard...

The addition of iron to high-nutrient low-chlorophyll (HNLC) oceanic waters stimulates phytoplankton, leading to greater primary production. Large-scale artificial ocean iron fertilization (OIF) has been proposed as a means of mitigating anthropogenic atmospheric CO(2), but its impacts on ocean ecosystems below the photic zone are unknown. Natural...

Siderophore type chelates were detected in nutrient enriched, incubated seawater collected from different biogeographical regions of the Atlantic Ocean. Seawater was enriched with glucose and ammonium, glycine (as a source of carbon and nitrogen) or chitin and ammonium at different concentrations and was incubated for up to 3–4days in the dark. Sid...

Samples collected at two different depths (ca. 3200 and ca. 4200 m) in the Setúbal and Cascais canyons off the Portuguese coast, during the HERMES RRS Charles Darwin cruise CD179, were analysed for (1) sediment biogeochemistry (TOC, TN) and (2) composition, and structural and trophic diversity of nematode communities. Multivariate PERMANOVA analysi...

Burial of organic carbon (OC) in marine sediments moderates atmospheric CO2 levels on geological time scales, but uncertainties remain about how much OC is buried and about the efficiency of OC burial, particularly in heterogeneous seafloor environments such as ocean margins. Here we describe OC burial in Nazare submarine canyon and the adjacent co...

The Crozet Plateau is an area of interest as it is a region of the Southern Ocean where annual primary productivity is relatively high. We describe spatial and temporal variations in the biomarker distributions and carbon and nitrogen isotopic signatures of organic matter formed within surface waters around the plateau during an algal bloom. In the...

Holothurians dominate the abyssal megabenthos. They are key consumers and bioturbators of surficial sediment. Compounds essential for holothurian reproduction, such as carotenoids, are in short supply in the deep ocean. Holothurians cannot synthesise carotenoids de novo; the compounds are supplied with the flux of phytodetritus. Therefore, the supp...

Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results fro...

Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lip...

During HERMES cruises in spring 2006 and 2007 to a cold-water coral (CWC) reef at the border between Norway and Sweden, we studied effects of the reef on the quality (C/N ratio) of suspended particles. The Tisler reef is situated on top of a southeast-northwest-oriented sill forming the connection between the Kosterfjord and the open Skagerrak. In...

The Nazare submarine canyon extends similar to 210 km westward from the coast of Portugal, down to a water depth of > 4300 m. The considerable habitat heterogeneity found throughout the canyon is affected by strong currents and high turbidity, especially in the upper parts of the canyon. The canyon morphology comprises steep slopes, scarps, terrace...

Submarine canyons are key environments on the continental margin that are affected by unique and dynamic but often episodic and complex processes, and are difficult to study. Canyons are considered hotspots of biodiversity and enhancement of primary productivity at canyon heads has often been postulated to support this, although the evidence is spa...

The temporal and spatial variability in the water-column distribution of dissolved organic carbon (DOC), and the particulate organic matter, collected both with bottles (POM-b) and in situ pumps (POM-p), was studied around Sedlo and Seine, two seamounts located in subtropical waters of the northeast Atlantic Ocean. Seine and Sedlo presented high PO...

A synthesis is provided of dissolved organic nitrogen (DON) and phosphorus (DOP) distributions over the Atlantic Ocean based upon field data from eight recent transects, six meridional between 50°N and 50°S and two zonal at 24° and 36°N. Over the entire tropical and subtropical Atlantic, DON and DOP provide the dominant contributions to total nitro...

The Arabian Sea is subject to intense seasonality resulting from biannual monsoons, which lead to associated large particulate fluxes and an abundance of organic carbon, a potential food source at the seafloor for benthic detritivores. We used the stable isotopes of carbon and nitrogen alongside lipid analyses to examine potential food sources (par...

An extremely well-preserved dinosaur (Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and...