Daniel Roy Parsons

University of Hull · Department of Geography, Environment and Earth Sciences

"Consider the [turbidity] current as ... a river" R. A. Bagnold (1962); the foundation of contemporary deep marine sedimentology. Gravity currents, such as sediment-laden turbidity currents, are ubiquitous natural flows that are driven by a density difference. Turbidity currents have provided vital motivation to advance understanding of this class...

Rivers are the major conveyor of plastics to the marine environment, but the mechanisms that impact microplastic (<5 mm) aquatic transport, and thus govern fate are largely unknown. This prevents progress in understanding microplastic dynamics and identifying zones of high accumulation, along with taking representative environmental samples and dev...

Shallow tidal environments are very productive ecosystems but are sensitive to environmental changes and sea level rise. Bio-morphodynamic control of these environments is therefore a crucial consideration; however, the effect of small-scale biological activity on large-scale cohesive sediment dynamics like tidal basins and estuaries is still large...

The existence of ancient fluvial systems on Mars is widely accepted, but little is known about how quickly they formed, or what environmental conditions controlled their evolution. We analyzed a sequence of well-preserved inner-bank bar deposits within the meander bends of a multistacked sinuous fluvial ridge in Aeolis Dorsa and compared them to si...

This paper discusses the geological evolution of the Paraná River in Corrientes Province, located inside the Mesopotamic Argentine region, and reviews the principal geomorphological and hydro-sedimentological characteristics of this outstanding fluvial system. Active lateral migration of the Paraná River inside its large alluvial fan, which covers...

Estuaries are dynamic landscapes with complex bar and channel patterns formed by interactions between tidal and fluvial currents. River discharge dampens the tidal wave, enhances the ebb flow, and supplies sediment to the estuary. However, it is largely unknown how river discharge influences overall estuary morphology. The objective of the current...

Landslide-dams, which are often transient, can strongly affect the geomorphology, and sediment and geochemical fluxes, within subaerial fluvial systems. The potential occurrence and impact of analogous landslide-dams in submarine canyons has, however, been difficult to determine due to a scarcity of sufficiently time-resolved observations. Here we...

Hydrochars are an alternative form of biochar produced by hydrothermal carbonisation (HTC), a potentially cheaper and greener method. In this paper, the effect of multiple variables on hydrochar properties was investigated. Waste biomass was converted to hydrochar via microwave-assisted hydrothermal carbonisation. The variables were temperature, so...

The unsteady dynamics and induced turbulence associated with flow development of a fully-submerged canopy with relatively low flexibility were explored experimentally under small Cauchy numbers Ca≲9 using particle image velocimetry (PIV) and particle tracking velocimetry (PTV). Inspection of the flow around a rigid canopy supported the identificati...

Marine biofilms are functional communities that shape habitats by providing a range of structural and functional services integral to coastal ecosystems. Impacts of climate change on biological aspects of such communities are increasingly studied, but impacts on the chemicals that mediate key interactions of biofilm organisms have largely been over...

Here we show how major rivers can efficiently connect to the deep-sea, by analysing the longest runout sediment flows (of any type) yet measured in action on Earth. These seafloor turbidity currents originated from the Congo River-mouth, with one flow travelling >1,130 km whilst accelerating from 5.2 to 8.0 m/s. In one year, these turbidity current...

“Consider the [turbidity] current as that of a river” R. A. Bagnold (1962);the foundation of contemporary deep marine sedimentology.Submarine sediment-laden buoyancy-driven flows, or turbidity currents, are critical as key vectors for material, nutrient, and pollutant dispersal in the world’s oceans. Extant models of turbidity currents assume that...

The delivery and burial of terrestrial particulate organic carbon (OC) in marine sediments is important to quantify, because this OC is a food resource for benthic communities, and if buried it may lower the concentrations of atmospheric CO2 over geologic timescales. Analysis of sediment cores has previously shown that fjords are hotspots for OC bu...

River dams provide many benefits, including flood control. However, due to constantly evolving channel morphology, downstream conveyance of floodwaters following dam closure is difficult to predict. Here, we test the hypothesis that the incised, enlarged channel downstream of dams provides enhanced water conveyance, using a case study from the lowe...

Biosorbents are an alternative pollutant adsorbent, usually sourced from waste biomass and requiring little to no treatment. This makes them cheaper than conventional adsorbents. In this paper, green pea ( Pisum sativum) haulm was used as a biosorbent for the adsorption of methylene blue dye. The potential application of pea haulm as a biosorbent h...

Deltas are home to 4.5% of the global population and support a range of ecosystem services that are vital to lives and livelihoods. As low-lying regions, deltas are also amongst the most vulnerable areas to the threat climate change and relative sea-level rise, which are being exacerbated by ongoing local resource exploitation. Anthropogenic activi...

Until recently, despite being one of the most important sediment transport phenomena on Earth, few direct measurements of turbidity currents existed. Consequently, their structure and evolution were poorly understood, particularly whether they are dense or dilute. Here, we analyze the largest number of turbidity currents monitored to date from sour...

The study of wave-structure interactions involving nonlinear forces would often make use of the popular hybrid frequency–time domain method. In the hybrid method, the frequency-domain analysis could firstly provide the reliable and accurate dynamic parameters and responses; then these parameters and responses are transformed to the parameters to es...

Shallow tidal environments are very productive ecosystems yet are sensitive to environmental changes and sea level rise. Bio-morphodynamic control of these environments is therefore a crucial consideration; however, the effect of small-scale biological activity on large-scale cohesive sediment dynamic like tidal basins and estuaries is still largel...

Current panel methods for wave-structure interactions employ the potential flow theory, which provide fast, reliable and relatively accurate predictions for the marine structures, and now some open source packages, NEMOH and HAMS, are available. In this research, the relative utility and performance of NEMOH and HAMS is compared with the well-known...

Rivers are the major conveyor of plastics to the marine environment, but the mechanisms that impact microplastic (< 5mm) transport, and thus govern fate of the material in the environment, are largely unknown. This prevents progress in understanding microplastic dynamics and identifying zones of high accumulation, as well as curtailing the evolutio...

The distinct turbulence dynamics and transport modulated by a common seagrass species were investigated experimentally using a flexible surrogate canopy in a refractive-index-matching environment that enabled full optical access. The surrogate seagrass replicated the dynamic behaviour and morphological properties of its natural counterpart. The flo...

This paper quantifies changes in primary dune morphology of the mesotidal Lower Columbia River (LCR), USA, through ~ 90 river kilometres of its fluvial‐tidal transition at low‐river stage. Measurements were derived from a Multibeam Echo Sounder dataset that captured bedform dimensions within the thalweg (≥ 9m depth; H/Hmax ≥ 0.7) of the LCR main ch...

Rivers link terrestrial and ocean environments, distributing fresh water, nutrients, and sediment to diverse ecosystems. Over the past 50 years, rivers have become increasingly significant vectors for plastic pollution. Lowland riverbeds exhibit coherent features including ripple and dune bedforms, which transport sediment downstream via well-under...

The near‐bed section of submarine gravity flows travels at the highest and most destructive speeds making direct measurements of this region of the flow difficult. Here results are presented from “boulder‐like” Benthic Event Detectors (BEDs) that measured their own rotation, depth and temperature while carried within the near‐bed region of gravity...

Marine biofilms are functional communities that shape habitats by providing a range of structural and functional services integral to coastal ecosystems. Impacts of climate change on biological aspects of such communities are increasingly studied, but impacts on the chemicals that mediate key interactions of biofilm organisms have largely been over...

Here we document for the first time how major rivers connect directly to the deep-sea, by analysing the longest runout sediment flows (of any type) yet measured in action. These seafloor turbidity currents originated from the Congo River-mouth, with one flow travelling >1,130 km whilst accelerating from 5.2 to 8.0 m/s. In one year, these turbidity...

Dunes are the most prevalent bedform present in sand‐bedded rivers and their morphology typically comprises multiple scales of three‐dimensional topography. However, our understanding of flow over dunes is predicated largely on two‐dimensional models, a condition which is rare in nature. Here, we present results of Large Eddy Simulations over a sta...

Marine microplastics accumulate in sediments but impacts on ecosystem functions are poorly understood. Microplastics interactions with stabilizing benthic flora/fauna or biostabilization processes, have not been fully investigated, yet this is critical for unravelling microplastics effects on ecosystem-scale processes and functions. This is also vi...

The effect of bedforms on frictional roughness felt by the overlying flow is crucial to the regional modelling of estuaries and coastal seas. Bedforms are also a key marker of palaeoenvironments. Experiments have shown that even modest biotic and abiotic cohesion in sand inhibits bedform formation, modifies bedform size, and slows bedform developme...

Water column data collected from moorings in Monterey Canyon, offshore California These water column data files were collected in Monterey Canyon as part of the Monterey Canyon Coordinated Canyon Experiment (CCE). The CCE was set up to measure the passage of sediment gravity flows down Monterey Canyon. A dense array of sensors (more than 50) were d...

Sediments composed of mixed cohesive clay and non-cohesive sand are widespread in a range of aquatic environments. The dynamics of ripples in mixed sand–clay substrates have been studied under pure current and pure wave conditions. However, the effect of cohesive clay on ripple development under combined currents and waves has not been examined, ev...

The world's large rivers are facing reduced sediment loads due to anthropogenic activities such as hydropower development and sediment extraction. Globally, estimates of sand extraction from large river systems are lacking, in part due to the pervasive and distributed nature of extraction processes. For the Mekong River, the widely assumed estimate...

The scale of submarine channels can rival or exceed those formed on land and they form many of the largest sedimentary deposits on Earth. Turbidity currents that carve submarine channels pose a major hazard to offshore cables and pipelines, and transport globally significant amounts of organic carbon. Alongside the primary channels, many systems al...

Coasts are among the most intensely used environments on the planet, but they also present dynamic and unique hazards, including flooding and erosion. Sea level rise and changing wave climates will alter patterns of erosion and deposition, but some existing coastline evolution models are unable to simulate these effects due to their one-dimensional...

Accurate wave forecasts are essential for the safe and efficient maritime operations and, in particular, the maintenance of offshore wind farms. Here, machine learning and remote monitoring from satellites are integrated to provide uniquely detailed predictions of significant wave height (SWH). C-Band Synthetic Aperture Radar images from European S...

On the list of challenges facing the world largest deltas, increased saline water intrusion (SWI) in the surface water system and its role in jeopardizing freshwater supply are often ranked very high. Yet, detailed process-based studies of SWI at the whole delta scale are limited, and the trends are regularly associated with global sea level rise....

In October 2019 the central 28m telescope of the H.E.S.S. experiment has been upgraded with a new camera. The camera is based on the FlashCam design which has been developed in view of a possible future implementation in the medium-sized telescopes of the Cherenkov Telescope Array (CTA). We report here on the results of the science verification pro...

The weathering of carbonate rocks with sulfuric acid releases carbon dioxide (CO2) to the atmosphere, offsetting the CO2 drawdown from carbonic acid weathering of silicates thought to regulate global climate. Quantifying CO2 release from sulfuric acid weathering requires the partitioning of riverine sulfate between its two main sources: sedimentary...

Low-angle dunes (LADs) are recognized as the most common roughness element in large fluvial rivers and estuaries. Comprehending their development is vital to understand the flow and sediment dynamics, and paleo-environmental reconstruction of the geological record. However, our understanding of LADs evolution under unsteady flows is poorly understo...

With riverine flooding set to be more frequent in many parts of the world as a result of climate change, the interactions between fluvial morphodynamics and riparian vegetation may depend in part on the sequence of flood events. This paper describes a laboratory study of the geomorphic adjustment of a braided river to sequences of floods across fiv...

Bio-based plastics were designed to replace single-use plastics and to cause less post-consumer environmental damage. This paper assesses the weathering of four bio-based polymers created by ring opening polymerization (ROP) promoted by a previously reported Ti-based catalyst, to detect any problems before production was scaled up. Samples were age...

Many of the world's major river deltas face a sustainability crisis, as they come under threat of increases in salinity and the extent of tidal zones forced by combinations of sea-level rise, changes in river discharge and channel geometry. The relative contribution of these factors to future increases in tidal extent remains unconstrained, with mo...

The development of a coherent and coordinated policy for the management of large socio-agricultural systems, such as the Mekong delta in southern Vietnam, is reliant on aligning the development, delivery, and implementation of policy on national to local scales. Effective decision making is linked to a coherent, broadly-shared vision of the strateg...

The world's large rivers are facing reduced sediment loads due to anthropogenic activities such as hydropower development and sediment extraction. Globally estimates of sand extraction from large river systems is lacking, in part due to the pervasive and distributed nature of extraction processes. In the Mekong River, current basin wide estimates o...

Turbidity currents dominate sediment transfer into the deep ocean, and can damage critical seabed infrastructure. It is commonly inferred that powerful turbidity currents are triggered by major external events, such as storms, river floods, or earthquakes. However, basic models for turbidity current triggering remain poorly tested, with few studies...

Natural flood management (NFM) promotes the sustainable enhancement of natural fluvial processes to reduce flooding (SEPA, 2015; Wilkinson et al., 2019), and is increasingly popular for use by community groups, contractors and governments (Kay et al., 2019). Reintroduction of wood to a river channel is a popular form of NFM often achieved through s...

Submarine channels deliver globally important volumes of sediments, nutrients, contaminants and organic carbon into the deep sea. Knickpoints are significant topographic features found within numerous submarine channels, which most likely play an important role in channel evolution and the behaviour of the submarine sediment‐laden flows (turbidity...

Hydraulic roughness is a fundamental parameter in the understanding and simulation of hydro- and sediment-dynamics over dunes in fluvial and coastal areas. Completely understanding the links between the turbulent flow field, sediment transport and morphodynamics is key to better quantifying the evolving roughness in time and space. This paper prese...

The livelihoods of millions of people living in the world's deltas are deeply interconnected with the sediment dynamics of these deltas. In particular a sustainable supply of fluvial sediments from upstream is critical for ensuring the fertility of delta soils and for promoting sediment deposition that can offset rising sea levels. Yet, in many lar...

There is evidence that microplastic (MP) pollution can negatively influence coral health; however, mechanisms are unknown and most studies have used MP exposure concentrations that are considerably higher than current environmental conditions. Furthermore, whether MP exposure influences coral susceptibility to other stressors such as ocean warming...

In the list of challenges facing the world largest deltas, increased salt intrusion and its role in jeopardizing freshwater supply is often ranked very high. Yet, detailed process-based studies of salt intrusion at the whole delta scale are limited and the trends are regularly associated to global sea level rise. Here, using field measurements and...

We are the midst of a climate emergency requiring urgent climate action that is as yet unforthcoming both on the scale and at the speed needed. This article considers this current state of inaction and how we might understand the processes of attitudinal and behavioural change needed through the emotional framework of loss. These issues are further...

We present the results of flume experiments, conducted in the Total Environment Simulator at the University of Hull, that aim to provide a fuller understanding of the influence of physical cohesion (abiotic clay content) on ripple development under combined wave and current flow Experiments including three runs were performed with wave-dominated co...

Current understanding of the role that dunes play in controlling bar and channel-scale processes and river morphodynamics is incomplete. We present results from a combined numerical modeling and field monitoring study that isolates the impact of dunes on depth-averaged and near-bed flow structure, with implications for morphodynamic modeling. Numer...

This study focuses on the interactions between sediment stability and biological and physical variables that influence the erodibility across different habitats. Sampling at short‐term temporal scales illustrated the persistence of the microphytobenthos (MPB) biomass even during periods of frequent, high physical disturbance. The role of MPB in bio...