Voyage winter 2017

This the first major expedition in the HADES-ERC project, and we will target the Oligotrophic Kermadec Trench using the research vessel Tangaroa.

(An oligotrophic environment is an environment that offers little to sustain life).

Photo: Dave Allen, NIWA.

The overall research objective of the voyage is to explore the potential implication of variability in carbon supply for diagenesis (how sediments turn to rock)and the abundance/characteristics of viral, microbial, meiofaunal and macrofaunal communities along the trench axis of the Kermadec Trench – as compared to abyssal reference stations.

Six sites along the central axis of the Kermadec Trench and two abyssal references sites will be targeted (see Figure 1 and Table 1).

The trench sites have been chosen as they should cover the maximum range of anticipated carbon deposition rates along the trench axis. The two reference sites simply represent a northern and a southern site covering any potential latitude gradient in ocean productivity.

Figure 1: Bathymetric map showing study sites in the Kermadec Trench. Inset shows the study area relative to New Zealand.

 Table 1:  
Site 1  9545 meters deep
 Site 2   9782 meters deep
 Site 3  9592 meters deep
 Site 4  9488 meters deep
 Site 5  10039 meters deep
 Site 6  9693 meters deep
 Site 7  6051 meters deep
 Site 8   6047 meters deep

During the voyage we will deploy two types of autonomous benthic landers for quantifying the in situ diagenetic activity and pathways in the sediment.

In particular we will use microsensors for mapping the O2 and NO3- concentrations in the surface sediment and use 15N tracer incubations for quantifying in situ N cycling in the upper 25 cm of the sediment.

Camera landers will be used for characterizing the benthic settings and explore macrofaunal communities. Furthermore, sediment will be recovered for geochemical, microbial and biological investigations.

Water samples will be collected by rosette systems for characterization of particle dynamics and microbial investigations.

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