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01 October 2000 - Crossing the Equator

RRS James Clark Ross: Diary entry, October 1st 2000

Noon Position : 10° 58' South 18° 20' West
Distance travelled since Grimbsy: 4762 Nautical Miles
Air temperature @ noon: 24.4 degrees Celsius
Sea temperature @ noon: 24.4 degrees Celsius


CROSSING THE EQUATOR
On Tuesday 26 September 2000, RRS James Clark Ross crossed the Equator at 19:29 hours. The Ceremony that ensued goes back many, many years to when ships first started transiting the Equator and involves all those who have not previously crossed the Equator by sea, or have no appropriate certificate to prove their crossing. They are required to go before the Court of Neptune, where their sins are read out, and the punishments bestowed. It was of course a solemn and serious occasion, and this year involved a very large number (12) of unlucky victims / first timers.

King Neptune and his lovely wife arriving onboard


King Neptune and his lovely wife arriving onboard.

On the arrival of King Neptune and his wife, Queen Nefertiti, at the Court, all those uninitiated victims were requested to report to the Court forthwith. Unfortunately many people went immediately into hiding to try to avoid the inevitable. The police force, armed with batons ( later found to be made of foam), were thus deployed to search the ship and escort any of the victims back to face the Judge (as seen in the photo below).

The court of Injustice

The court of "Injustice"

Upon arrival at the Court, the victim was required to kneel before the King and then had to kiss his "Kipper", after which the charges were read out and the defendant was asked to plead "guilty" or "not guilty". Their response is supposed to affect the outcome ( i.e. their punishments), however despite their plea the result was still a horrific barrage of punishments.These included a few general ones handed out to the many, such as:

1)    Taking the Doctor's medicine
2)    Getting covered in slop - a foul green mixture of unknown ingredients
3)    Having a hair cut and shave from the "experienced" barber

In addition to this there were also a few more specific punishments, aimed at certain individuals and their sins, but I'm afraid both the charges and appropriate punishments are too outrageous to put into print, or more realistically may cause too much embarrassment! Below are a few photos capturing some of the action..


Emilio kissing the kipper Sandy getting the Slop Marcos and the barber
Emilio kissing the kipper Sandy getting the "Slop" Marcos and the barber

LAND AT LAST
A few days later (30 September), RRS James Clark Ross passed 13 nautical miles off of Ascension Island.  Ascension Island lies at 7 degrees 57 minutes South and 14 degrees 21 minutes West, covering an area of 34 square miles.  The island is a British / NATO communications centre which currently has a population of 1,131 (280 GB, 148 USA, 703 St Helenian Citizens).  The island has only one area of vegetation on 'Green Mountain' and is described as "a graceful oasis amidst waste and desolation".  The island was discovered on 'Ascension Day' 20th May 1501 by the Portugese, Joao de Nova Gallego. British Royal Marines have garrisoned the island since 1821.

Ascension Island in the distance


Ascension Island in the distance

SCIENCE
In addition to the Atlantic Meridional Transect (AMT) -11 science programme, geophysicists Alex Cunningham (BAS Geological Sciences Division) and Neil Mitchell (University of Cardiff) are collecting data using the Simrad EM -120 multibeam echosounder (Swath Bathymetry) installed earlier this year on RRS James Clark Ross. The EM -120 has been in operation since July, and has already produced some spectacular results.


Alex post Slop
Neil and Alex at work on the EM -120
Neil who had a Certificate
Alex post "Slop"
Neil and Alex at work on the EM -120
Neil who had "a Certificate"

The multibeam system regularly transmits an acoustic pulse or ‘ping’ which propagates through the water column and is reflected back from the nearby sea floor. The reflected signal is recorded and used to determine sea-floor depth along a narrow strip perpendicular to the ship’s track. Successive pings are used to build up a two-dimensional picture of sea floor topography, in a similar way to the generation of pictures on a television screen. In addition, the EM -120 generates ‘side-scan sonar’ data, which provide an acoustic image of the sea floor derived from variations in surface roughness.

Why map the sea floor ? Geophysicists can determine a great deal about the geological history of an area from its sea-floor topography. For example, topographic patterns or ‘fabrics’ generated by sea-floor spreading at mid-ocean ridges actually record a history of relative motion between the tectonic plates involved. As well as recording past movements, sea-floor topography tells us much about modern processes in geologically active regions such as mid-ocean ridges and trenches. Swath data also provide information about sediment deposition, and have been used to image submarine canyons and channel systems, sediment waves (similar to sand dunes, but migrating up-current), and huge submarine landslides.

On this leg, we have two principal objectives. The first is to collect data opportunistically on passage between the AMT stations. This work constitutes the start of a proposed long-term project to map unexplored regions of the Atlantic using data collected on passage to and from the Antarctic. The second objective is to survey a short section of the Mid-Atlantic Ridge, where new ocean crust is forming at the boundary between the South American and African tectonic plates. We have two days' survey time reserved for this purpose. Mid-ocean ridges are of intense interest to geophysicists, and multibeam data tell us much about the processes associated with the creation of new ocean floor at these sites. Our survey covers a previously unmapped section of the Mid-Atlantic Ridge located just south of the Equator.

The figure below shows swath bathymetry data collected in the Western Approaches shortly after leaving the UK. The data extend across the lower continental slope, and show that it is dissected by submarine canyons; closer examination reveals gullies on the canyon walls. Submarine canyons are of particular interest as they form pathways for sediment transported from the continental shelf edge to the deep ocean.

Continental Slope Morphology, Click for larger imageContinental Slope Morphology, Southwestern Approaches (click on the image for a larger version).



SCIENCE WEEK FROM THE Principal Scientist (Malcolm Woodward)
  Another week has passed by very quickly, including the very enjoyable "day of judgement", and now gradually thoughts are starting to turn to the end of the cruise in Montevideo. Scientifically, the last week has been one of  great oceanographic contrasts. As reported last week we had come to the south of West Africa and the sea temperature had increased to 29.5 degrees Celsius, the outside temperatures were over 30 degrees Celsius and the humidity was very high. We then were diverting away from the ‘normal’ AMT track which has for the last five years turned to the south-west at that point to head down across the southern gyre and offshore the Brazilian coast to terminate off Uruguay.

This year we changed our ‘normal’ track due to the Swath Bathymetry survey, and we headed to the south-east, to the position 01 degrees 00.0’S 13 degrees 37.0’W. This area turned into a piece of ‘science of opportunity’ for the biogeochemistry scientists. We had been observing from satellite images of both sea-surface temperature and the composite SeaWiFs chlorophyll charts that this area was one where the Equatorial upwelling was very strong, and this upwelling is rarely studied because of its remoteness.

As we came south towards the upwelling area in a space of 12 hours, which was about 120 miles, the surface water temperature dropped from 28.6 degrees Celsius to 24.2 degrees Celsius, the chlorophyll concentrations increased greatly and the salinity increased. At the first CTD station in this area there was obvious evidence of upwelling. Apart from the low surface water temperatures, the concentration of nitrate was enhanced up to 3 micromoles per litre (this  contrasted to 0.003 micromoles per litre to the station outside the upwelling), and the other macro nutrients of phosphate, silicate, and ammonium were also enhanced in the surface waters. The depth integrated primary production was also increased. We carried five CTD stations in close proximity to each other, giving a good coverage for the area. Our science operations worked well in symbiosis with the Swath Bathymetry survey.

Since then we have headed almost in a straight line for Montevideo, except for a small deviation to within 13 miles of Ascension Island for an opportunistic Swath Bathymetry survey of an undersea volcano. A day later we are still under the influence of the upwelling region, but gradually the temperature off the water is increasing and the surface nutrients and chlorophyll fluorescence have dropped to low levels, indicating what should be a week of oligotrophic study sites in the south Atlantic gyre.


Weekly diary entries