September 2011

On Friday the 23rd of September....

Jeff and Cathy present a description of hydrothermal plume sampling and analysis at the East Scotia Ridge vent sites in the Southern Ocean

On Monday 5th of September....

Jessy Klar will present:

Title:
Dissolved aluminium distributions in the Atlantic Ocean: three study areas

Abstract: While it is well accepted that oceanic primary production (and therefore carbon drawdown) relies on the availability of Fe and other trace metals (such as Zn, Cd, etc) it is important to quantify the sources of these elements to the surface ocean. Aluminium (Al) has no known function within living cells but is a very useful tracer to estimate atmospheric dust deposition, one of the most important input mechanisms of Fe to surface waters of the open ocean.

Here we present dissolved aluminium (dAl) distributions in the open ocean from three different study areas within the Atlantic Ocean. In first place three cruises were conducted in 2010 in the Irminger Basin Iron Study (IBIS) in the High Latitude North Atlantic Ocean (HLNAO). Subsequently, high resolution dAl seawater samples have been collected during two GEOTRACES studies, one in the South Atlantic Ocean (GA10, 2010) and one in the Tropical Atlantic (GA06, 2011).

Dissolved aluminium in seawater was analysed onboard with a Flow Injection method using pre-concentration of Al onto Toyopearl resin (AF-Che-650M) and detection through lumogallion-Al fluorescence (Resing and Measures, 1994; Brown and Bruland, 2008).

The distributions of dAl in these three key areas of the Atlantic Ocean indicate significant differences of supply rates. The analysis of this data should improve our understanding about the ongoing global biogeochemical processes in the ocean.

July 2011

On Friday 1st July....

Ben Russell will present:

Title:
Developing a rapid and efficient actinide and Sr-90 analysis facility for
contaminated land assessment.

and Jade Burraston will present:

Title:
Advancing low-level radionuclide analysis using HR sector field plasma
mass spectrometry.

June 2011

On Friday 17th June....

Chris Stevenson will present:

Title:
The flows that left no trace: investigating channelised large-volume turbidity currents that bypassed sediment without eroding the seafloor

Abstract:

Submarine channels are the main conduits for sediment transport in the ocean, from continental shelf to abyssal plain. Individual flow events can transport >100 km³ of sediment and deposit across vast areas of seafloor; these flows are therefore responsible for some of the largest sediment accumulations on Earth. Seafloor gradient exerts a major control on the ability of sediment flows to erode/bypass and transport sediment. In particular, recent work off Northwest Africa has highlighted the influence of seafloor gradient on turbidity currents passing through deep-water channels (e.g. Wynn et al., in press). We build upon these recent studies by utilizing a spatially extensive core correlation framework across the Madeira Distributary Channel System, offshore Northwest Africa. These shallow channels (~20 m deep) extend for over 700 km and connect two large basins that form part of the extensive Moroccan Turbidite System. Over the last 400 ka this system has been host to some of the largest gravity flows ever recorded on Earth, with run out distances exceeding 2000 km and volumes >150 km³. Excellent core control, coupled with a robust geochemical and chronostratigraphic framework, enables individual flow events to be documented in both down-flow and across-flow directions.