scholarly journals RiverOceanPlastic: Land-ocean transfer of plastic debris in the North Atlantic, Cruise No. AL534/2, 05 March – 26 March 2020, Malaga (Spain) – Kiel (Germany)

2020 ◽  
Author(s):  
Aaron Beck
Keyword(s):  
Water Column ◽  
Water Samples ◽  
Western Europe ◽  
Suspended Particle ◽  
Plastic Debris ◽  
The North ◽  
Research Initiative ◽  
Different Depths ◽  
Calm Weather

Cruise AL534/2 is part of a multi-disciplinary research initiative as part of the JPI Oceans project HOTMIC and sought to investigate the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus of the cruise was on the horizontal transfer of plastic debris from major European rivers into shelf regions and on the processes that mediate this transport. Stations were originally chosen to target the outflows of major European rivers along the western Europe coast between Malaga (Spain) and Kiel (Germany), although some modifications were made in response to inclement weather. In total, 16 stations were sampled along the cruise track. The sampling scheme was similar for most stations, and included: 1) a CTD cast to collect water column salinity and temperature profiles, and discrete samples between surface and seafloor, 2) sediment sampling with Van Veen grab and mini-multi corer (mini-MUC), 3) suspended particle and plankton sampling using a towed Bongo net and vertical WP3 net, and 4) surface neusten sampling using a catamaran trawl. At a subset of stations with deep water, suspended particles were collected using in situ pumps deployed on a cable. During transit between stations, surface water samples were collected from the ship’s underway seawater supply, and during calm weather, floating litter was counted by visual survey teams. The samples and data collected on cruise AL534/2 will be used to determine the: (1) abundance of plastic debris in surface waters, as well as the composition of polymer types, originating in major European estuaries and transported through coastal waters, (2) abundance and composition of microplastics (MP) in the water column at different depths from the sea surface to the seafloor including the sediment, (3) abundance and composition of plastic debris in pelagic and benthic organisms (invertebrates), (4) abundance and identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.

scholarly journals RV POSEIDON Fahrtbericht / Cruise Report POS536/Leg 1

2020 ◽  
Author(s):  
Mark Lenz
Keyword(s):  
Water Column ◽  
North Atlantic ◽  
Open Ocean ◽  
Minimum Size ◽  
Plastic Pollution ◽  
Near Surface ◽  
Plastic Debris ◽  
The North ◽  
Research Initiative ◽  
Different Depths

DIPLANOAGAP: Distribution of Plastics in the North Atlantic Garbage Patch Ponta Delgada (Portugal) – Malaga (Spain) 17.08. – 12.09.2019 The expedition POS 536 is part of a multi-disciplinary research initiative of GEOMAR investigating the origin, transport and fate of plastic debris from estuaries to the oceanic garbage patches. The main focus will be on the vertical transfer of plastic debris from the surface and near-surface waters to the deep sea and on the processes that mediate this transport. The obtained data will help to develop quantitative models that provide information about the level of plastic pollution in the different compartments of the open ocean (surface, water column, seafloor). Furthermore, the effects of plastic debris on marine organisms in the open ocean will be assessed. The cruise will provide data about the: (1) abundance of plastic debris with a minimum size of 100 μm as well as the composition of polymer types in the water column at different depths from the sea surface to the seafloor including the sediment, (2) abundance and composition of plastic debris in organic aggregates (“marine snow”), (3) in pelagic and benthic organisms (invertebrates and fish) and in fecal pellets, (4) abundance and the identity of biofoulers (bacteria, protozoans and metazoans) on the surface of plastic debris from different water depths, (5) identification of chemical compounds (“additives”) in the plastic debris and in water samples.

scholarly journals A 900-year New England temperature reconstruction from <i>in situ</i> seasonally produced branched glycerol dialkyl glycerol tetraethers (brGDGTs)

2018 ◽  
Author(s):  
Daniel R. Miller ◽  
M. Helen Habicht ◽  
Benjamin A. Keisling ◽  
Isla S. Castañeda ◽  
Raymond S. Bradley
Keyword(s):  
New England ◽  
Water Column ◽  
Lacustrine Sediments ◽  
Temperature Reconstruction ◽  
Early Spring ◽  
Pollen Record ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Glycerol Dialkyl Glycerol Tetraethers

Abstract. Paleotemperature reconstructions are essential for distinguishing anthropogenic climate change from natural variability. An emerging method in paleoclimatology is the use of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in lacustrine sediments to reconstruct temperature, but their application is hindered by a limited understanding of their sources, seasonal production, and transport. We report seasonally resolved measurements of brGDGT production within the water column, in catchment soils and in a sediment sequence from a small, deep inland lake in Maine, USA. BrGDGT distributions in the water column are distinct from catchment soils but similar to the distributions in lake sediments, suggesting that (1) brGDGTs are produced within the lake and (2) this in situ production dominates the downcore sedimentary signal. Seasonally, depth-resolved measurements indicate that the dominant production of brGDGTs occurs in late fall/early spring and at intermediate depths (18–30 meters) in the water column. We apply these observations to help interpret a 900-year-long brGDGT-based temperature reconstruction and find that it shows similar trends to a pollen record from the same site and to regional and global syntheses of terrestrial temperatures over the last millennium. However, the record also shows higher-frequency variability than has previously been captured by such an archive in the Northeastern United States, potentially attributed to the North Atlantic Oscillation and volcanic/solar activity. This is the first brGDGT- based multi-centennial paleoreconstruction from this region and contributes to our understanding of the production and fate of brGDGTs in lacustrine systems.

In-situ investigation of alkalinity - denitrification coupling in the sediment - water column interface

2020 ◽  
Author(s):  
Mona Norbisrath
Keyword(s):  
Water Column ◽  
German Bight ◽  
Anthropogenic Impacts ◽  
Binding Capacity ◽  
Quantitative Relationship ◽  
Terminal Electron Acceptor ◽  
The North ◽  
In Situ Investigation ◽  
In Situ Experiments

&lt;p&gt;&lt;strong&gt;Abstract: EGU 2020&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Session: BG4.1: Biogeochemistry of coastal seas and continental shelves (Helmuth Thomas)&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Mona Norbisrath&lt;sup&gt;1&lt;/sup&gt;, Kirstin D&amp;#228;hnke&lt;sup&gt;1&lt;/sup&gt;, Andreas Neumann&lt;sup&gt;1&lt;/sup&gt;, Justus van Beusekom&lt;sup&gt;1&lt;/sup&gt;, Nele Treblin&lt;sup&gt;1&lt;/sup&gt;, Bryce van Dam&lt;sup&gt;1&lt;/sup&gt;, Helmuth Thomas&lt;sup&gt;1&lt;/sup&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;Institute for Coastal Research, Helmholtz-Zentrum Geesthacht&lt;/p&gt;&lt;p&gt;Contact: [email protected]&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;In-situ investigation of alkalinity - denitrification coupling in the sediment - water column interface&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;As a shallow shelf sea, the North Sea is very vulnerable to anthropogenic impacts like rising CO&lt;sub&gt;2&lt;/sub&gt; concentrations, increasing nutrient inflows and coincident oxygen loss.&lt;/p&gt;&lt;p&gt;Two important processes that determine the role of the coastal ocean as a net sink for anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; are alkalinity and denitrification. Alkalinity, the acid binding capacity of the ocean, buffers natural and anthropogenic changes in the oceans&amp;#8217; CO&lt;sub&gt;2&lt;/sub&gt; and pH system. Denitrification, an anaerobic microbial process in which organic matter is respired, uses NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; instead of O&lt;sub&gt;2&lt;/sub&gt; as a terminal electron acceptor. Denitrification reduces NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; to N&lt;sub&gt;2&lt;/sub&gt; and in turn produces alkalinity.&lt;/p&gt;&lt;p&gt;Eutrophication, caused by leaching of excess fertilizer nutrients into coastal seas, leads to enhanced denitrification and therefore to enhanced alkalinity as well as an increased uptake of CO&lt;sub&gt;2&lt;/sub&gt;. However, the quantitative relationship between denitrification and alkalinity production and its control under changing environmental conditions is yet to be determined.&lt;/p&gt;&lt;p&gt;In the German Bight, denitrification is usually restricted to anoxic sediments. In this study, we therefore focus on in-situ experiments in the sediment - water column interface. Batch core incubations in combination with the isotope pairing technique (IPT) and labelled nitrate additions were used to detect denitrification and gauge its effect on alkalinity production during a cruise on RV Heincke (HE541) in September 2019 in the German Bight. To quantify denitrification, the production of all three N&lt;sub&gt;2&lt;/sub&gt; isotope species (&lt;sup&gt;28&lt;/sup&gt;N&lt;sub&gt;2&lt;/sub&gt;, &lt;sup&gt;29&lt;/sup&gt;N&lt;sub&gt;2&lt;/sub&gt; and &lt;sup&gt;30&lt;/sup&gt;N&lt;sub&gt;2&lt;/sub&gt;) is measured using a membrane inlet mass spectrometer (MIMS). We expect an increase of denitrification rates with nitrate concentrations and incubation times, and we will quantify benthic denitrification. We will further evaluate the assumption of concurrent increases in alkalinity production and will investigate the benthic-pelagic coupling of these processes. Investigating the in-situ interaction of metabolic alkalinity and denitrification will give an estimation of the alkalinity impact on the reduction of anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Turbulence and hypoxia contribute to dense zooplankton scattering layers in Patagonian Fjord System

2017 ◽  
Author(s):  
Iván Pérez-Santos ◽  
Leonardo Castro ◽  
Nicolás Mayorga ◽  
Lauren Ross ◽  
Luis Cubillos ◽  
...  
Keyword(s):  
Water Column ◽  
Vertical Mixing ◽  
Acoustic Doppler Current Profiler ◽  
Eddy Diffusivity ◽  
Future Research ◽  
Dense Layer ◽  
The North ◽  
Diel Vertical Migrations ◽  
And Migration

Abstract. The Puyuhuapi Fjord is an atypical fjord, with two mouths, located in northern Patagonia (44.7° S). One mouth lies to the south, close to the Pacific Ocean, whilst the second connects with the Jacaf Channel to the north where a shallow sill inhibits deep water ventilation contributing to the hypoxic conditions below ~ 100 m depth. Acoustic Doppler Current Profiler moorings, scientific echo sounder transects, and in-situ abundance measurements were used to study zooplankton assemblages and migration patterns along Puyuhuapi Fjord and Jacaf Channel. The acoustic records and in-situ zooplankton data revealed diel vertical migrations of siphonophores, euphausiids and copepods. A dense layer of zooplankton was observed along Puyuhuapi Fjord between the surface and the top of the hypoxic layer (~ 100 m), which acted as a physic-chemical barrier to the distribution and migration of the zooplankton. Aggregations of zooplankton and fishes were generally more abundant around the sill in Jacaf Channel than anywhere within Puyuhuapi Fjord. In particular, zooplanktons were distributed throughout the entire water column to ~ 200 m depth, with no evidence of a hypoxic boundary. Turbulence measurements taken near the sill in the Jacaf Channel indicated high turbulent kinetic energy dissipation rates (ε ~ 10−4 W kg−1) and vertical diapycnal eddy diffusivity (Kρ ~ 10−2 m2 s−1) values. These elevated vertical mixing ensures that the water column well oxygenated and promotes zooplanktons aggregation. The sill region represents a major topographic contrast between the two fjords, and we suggest that this is an feature for future research on carbon export and fluxes in these fjords.

scholarly journals A Methodology for Measuring Microplastic Transport in Large or Medium Rivers

Water ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 414 ◽  
Author(s):  
Marcel Liedermann ◽  
Philipp Gmeiner ◽  
Sebastian Pessenlehner ◽  
Marlene Haimann ◽  
Philipp Hohenblum ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Water Column ◽  
Turbulent Mixing ◽  
Suspended Sediments ◽  
High Flow ◽  
Danube River ◽  
Long Term Effects ◽  
Plastic Debris ◽  
Different Depths

Plastic waste as a persistent contaminant of our environment is a matter of increasing concern due to the largely unknown long-term effects on biota. Although freshwater systems are known to be the transport paths of plastic debris to the ocean, most research has been focused on marine environments. In recent years, freshwater studies have advanced rapidly, but they rarely address the spatial distribution of plastic debris in the water column. A methodology for measuring microplastic transport at various depths that is applicable to medium and large rivers is needed. We present a new methodology offering the possibility of measuring microplastic transport at different depths of verticals that are distributed within a profile. The net-based device is robust and can be applied at high flow velocities and discharges. Nets with different sizes (41 µm, 250 µm, and 500 µm) are exposed in three different depths of the water column. The methodology was tested in the Austrian Danube River, showing a high heterogeneity of microplastic concentrations within one cross section. Due to turbulent mixing, the different densities of the polymers, aggregation, and the growth of biofilms, plastic transport cannot be limited to the surface layer of a river, and must be examined within the whole water column as for suspended sediments. These results imply that multipoint measurements are required for obtaining the spatial distribution of plastic concentration and are therefore a prerequisite for calculating the passing transport. The analysis of filtration efficiency and side-by-side measurements with different mesh sizes showed that 500 µm nets led to optimal results.

Detection and characterization of SCVs in the North Atlantic

2020 ◽  
Author(s):  
Ashwita Chouksey ◽  
Xavier Carton ◽  
Jonathan Gula
Keyword(s):  
Atlantic Ocean ◽  
North Atlantic ◽  
Large Scale ◽  
North Atlantic Ocean ◽  
The North ◽  
Place Of Origin ◽  
Different Depths ◽  
The North Atlantic ◽  
Transport And Mixing

&lt;p&gt;In recent years, the oceanographic community has devoted considerable interest to the study of SCVs (Submesoscale Coherent Vortices, i.e. vortices with radii between 2-30 km, below the first internal radius of deformation); indeed, both mesoscale and submesoscale eddies contribute to the transport and mixing of water masses and of tracers (active and passive), affecting the heat transport, the ventilation pathways and thus having an impact on the large scale circulation.&lt;/p&gt;&lt;p&gt;In different areas of the ocean, SCVs have been detected, via satellite or in-situ measurements, at the surface or at depth. From these data, SCVs were found to be of different shapes and sizes depending on their place of origin and on their location. Here, we will concentrate rather on the SCVs at depth.&lt;/p&gt;&lt;p&gt;In this study, we use a high resolution simulation of the North Atlantic ocean with the ROMS-CROCO model. In this simulation, we also identify the SCVs at different depths and densities; we analyse their site and mechanism of generation, their drift, the physical processes conducting to this drift and their interactions with the surrounding flows. We also quantify their physical characteristics (radius, thickness, intensity/vorticity, bias in polarity: cyclones versus anticyclones). We provide averages for these characteristics and standard deviations.&amp;#160;&lt;/p&gt;&lt;p&gt;We compare the model results with the observational data, in particular temperature and salinity profiles from Argo floats and velocity data from currentmeter recordings.&amp;#160;&lt;/p&gt;&lt;p&gt;This study is a first step in the understanding of the formation, occurrences and structure of SCVs in the North Atlantic Ocean, of help to improve their in-situ sampling.&lt;/p&gt;

scholarly journals The International Soil Moisture Network: a data hosting facility for global in situ soil moisture measurements

2011 ◽  
Vol 8 (1) ◽  
pp. 1609-1663 ◽  
Author(s):  
W. A. Dorigo ◽  
W. Wagner ◽  
R. Hohensinn ◽  
S. Hahn ◽  
C. Paulik ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Water Cycle ◽  
Soil Moisture Data ◽  
The North ◽  
Time Period ◽  
Different Depths ◽  
Operational Networks

Abstract. In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. Nevertheless, on a worldwide basis the number of meteorological networks and stations measuring soil moisture, in particular on a continuous basis, is still limited and the data they provide lack standardization of technique and protocol. To overcome many of these limitations, the International Soil Moisture Network (ISMN; http://www.ipf.tuwien.ac.at/insitu) was initiated to serve as a centralized data hosting facility where globally available in situ soil moisture measurements from operational networks and validation campaigns are collected, harmonized, and made available to users. Data collecting networks share their soil moisture datasets with the ISMN on a voluntary and no-cost basis. Incoming soil moisture data are automatically transformed into common volumetric soil moisture units and checked for outliers and implausible values. Apart from soil water measurements from different depths, important metadata and meteorological variables (e.g., precipitation and soil temperature) are stored in the database. These will assist the user in correctly interpreting the soil moisture data. The database is queried through a graphical user interface while output of data selected for download is provided according to common standards for data and metadata. Currently (status January 2011), the ISMN contains data of 16 networks and more than 500 stations located in the North America, Europe, Asia, and Australia. The time period spanned by the entire database runs from 1952 until the present, although most datasets have originated during the last decade. The database is rapidly expanding, which means that both the number of stations and the time period covered by the existing stations are still growing. Hence, it will become an increasingly important resource for validating and improving satellite-derived soil moisture products and studying climate related trends. As the ISMN is animated by the scientific community itself, we invite potential networks to enrich the collection by sharing their in situ soil moisture data.

scholarly journals Provenance of tetraether membrane lipids in a large temperate lake (Loch Lomond, UK): implications for GDGT-based palaeothermometry

2014 ◽  
Vol 11 (3) ◽  
pp. 4187-4250 ◽  
Author(s):  
L. K. Buckles ◽  
J. W. H. Weijers ◽  
X.-M. Tran ◽  
S. Waldron ◽  
J. S. Sinninghe Damsté
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Membrane Lipids ◽  
Lacustrine Sediments ◽  
Small Rivers ◽  
The South ◽  
Factors Affecting ◽  
The North ◽  
Loch Lomond

Abstract. The application of glycerol dialkyl glycerol tetraether (GDGT)-based palaeoenvironmental proxies, such as the BIT index, TEX86 and the MBT/CBT palaeothermometer, has lately been expanded to lacustrine sediments. Given recent research identifying the production of branched, bacterial GDGTs (brGDGTs) within lakes, it is necessary to ascertain the effect of this lacustrine production on GDGT-based proxies. This study profiles a temperate, monomictic lake (Loch Lomond, UK), analysing labile intact polar GDGT lipids (IPLs) and resilient core GDGT lipids (CLs) in catchment soils, small tributary rivers, lake water and lake sediments. Loch Lomond consists of two basins bisected by the Highland Boundary Fault, resulting in a mesotrophic to oligotrophic gradient from south to north. The north basin is fjord-like, while the south basin is shallow with a lowland catchment. Besides abundant influxes of allochthonous soil and peat-derived (CL) brGDGTs, brGDGTs are produced in a variety of settings in Loch Lomond. Rather than integrating a scattered soil signal, there is some evidence that small rivers may contribute to the brGDGT pool through addition of brGDGTs produced in situ in these streams. 300 days of settling particles and water column profiles of suspended particulate matter (SPM; March and September 2011) reveal brGDGT production throughout the water column, with (IPL and CL) brGDGT distributions varying by basin. In lake sediments, in situ brGDGT production affects the distributions of sedimentary brGDGTs despite high soil and peat-derived organic matter influxes from the catchment. MBT/CBT-derived mean annual air temperature (MAAT) estimates from soil, river and lake sediments vary widely. A strong bias towards higher MAATs in the south and lower MAATs in the north basin further complicates the application of the proxy. These results emphasise that caution must be exercised when applying the MBT/CBT palaeothermometer to individual lakes in which the use of the proxy has not been validated and therefore the factors affecting its application are not well understood. Despite elevated BIT indices, (partly) due to in situ brGDGT production, reliable TEX86 lake surface temperature (LST) estimates were obtained from SPM with BIT indices up to 0.9 but containing abundant crenarchaeol. Lower north basin sediments yielded accurate LST estimates but require further evaluation to properly constrain the application of the TEX86 proxy.

First evidence of plastic fallout from the Great Pacific Garbage Patch

2020 ◽  
Author(s):  
Matthias Egger ◽  
Fatimah Sulu-Gambari ◽  
Laurent Lebreton
Keyword(s):  
Water Column ◽  
Water Depth ◽  
Environmental Concern ◽  
Numerical Models ◽  
Sea Surface ◽  
Polymer Composition ◽  
North Pacific Subtropical Gyre ◽  
Plastic Debris ◽  
The North ◽  
Oceanic Gyres

&lt;p&gt;Increasing amounts of plastic debris in the ocean is a global environmental concern. Each year, several million tons of plastic waste enter the ocean from coastal environments. Transported by currents, wind and waves, positively buoyant plastic objects eventually accumulate at the sea surface of subtropical oceanic gyres, forming the so-called ocean garbage patches. To date, the fate of floating plastic debris &amp;#8216;trapped&amp;#8217; in the oceanic gyres remains largely unknown. To more accurately assess the persistence of floating plastics accumulating in offshore areas, a better understanding of the plastic inputs and outputs into and from ocean garbage patches is crucial. An important component of this mass balance currently missing is the vertical plastic flux from the sea surface of subtropical waters towards the seabed. Numerical models have major difficulties in constraining the sinking flux of plastic to the ocean interior in these areas since validation against observational data is not possible yet.&lt;/p&gt;&lt;p&gt;Here, we provide the first water column profiles (0-2000m water depth) of plastic particles (&gt;500&amp;#181;m) in the North Pacific subtropical gyre (Great Pacific Garbage Patch; GPGP). We show that plastic particles in the water column are mostly in the size range of particles that are apparently missing from the ocean surface and that their polymer composition is similar to that of floating debris circulating in the surface waters. Furthermore, water column plastic concentrations increase with higher concentrations at the sea surface and show a power law decline with water depth. These findings strongly suggest that plastics present in the deep sea below the GPGP are small fragments of initially buoyant plastic debris that accumulated at the sea surface. Although the amount of plastic in the GPGP water column is significant compared to the surface accumulation, our results further indicate that the ocean water column is unlikely to harbor a major fraction of the tens of millions of metric tons of missing ocean plastic.&lt;/p&gt;

Experiments at Sea with Herders and In Situ Burning (HISB)

2017 ◽  
Vol 2017 (1) ◽  
pp. 2184-2203 ◽  
Author(s):  
David Cooper ◽  
Ian Buist ◽  
Steve Potter ◽  
Per Daling ◽  
Ivar Singsaas ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Open Water ◽  
Weather Conditions ◽  
Primary Objective ◽  
Sea Surface ◽  
The North ◽  
The North Sea ◽  
Series Of Experiments ◽  
Calm Weather

ABSTRACT A series of experiments involving herders and ISB (designated HISB) were conducted at sea on 14th – 15th June 2016, near the Frigg Field in the North Sea. The primary objective of the experiments described in this paper was to demonstrate, at near-full scale, the use of herders followed by in situ burning (ISB) in open water conditions and validate the findings of an earlier field study of herders in conjunction with ISB. Two experimental releases of 6 m3 (approximately 40 barrels) and one of 4 m3 of Grane Blend crude oil were undertaken. The released oil spread out differently on the sea surface in each of the slicks due to slight variations in release conditions and prevailing wind conditions. Herder (ThickSlick 6535) was applied around two of the slicks by spraying from a small boat; a third slick was not herded before ignition. In the first test, approximately 80% of the total amount of thick oil was herded to form a coherent slick with an average oil layer thickness of approximately 3 mm to 5 mm. The second herded slick accounted for 40% of the amount of oil released and resulted in an average layer thickness of approximately 2 mm to 3 mm present as several discrete areas of thick oil. The average oil layer thickness in the non-herded slick was 2.5 mm to 3 mm (under very calm weather conditions) and this slick had also been broken up into several discrete areas of thick oil. Ignition with gelled gasoline igniters was carried out approximately one hour after oil release. All three slicks were successfully ignited. Approximately 3.4 m3 of the available oil in the first herded slick was consumed in three distinct burns, while the second herded slick consumed 0.8 m3 of oil in only one burn. The remaining test involving an unherded slick consumed approximately 1.2 m3 of oil in three burns.

Sign in / Sign up

Export Citation Format

Share Document