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Nitrogen from
human activity has been polluting lakes in the northern
hemisphere since the late 19th century. The clear signs of
industrialisation can be found even in very remote lakes,
thousands of kilometres
from the nearest city.
Research is on studies of sediment from 36 lakes in the USA,
Canada, Greenland and Svalbard, Norway.
Both the species composition and production
of diatoms, microscopic siliceous algae, have changed
dramatically in the lakes of Svalbard since the start of the
20th century, with the most significant changes over the past
decades.
Combustion of fossil fuels and use of
fertilisers are the main sources of
the increasing amount of nitrogen which is transported with air
currents for thousands of kilometres and reaches the ground in
rain or snow. Nitrogen is an important nutrient for plants, but
overuse in more intensive farming can lead to pollution of
watercourses, smog and acid rain in urban environments. However
little is known about the effects in the more remote areas, but
an increasing number of studies in Arctic lakes are now showing
major changes in the ecosystem.
 A
hydrogen-powered fuel cell unmanned air vehicle (UAV), called
Ion Tiger, developed by The Naval Research Laboratory, has set
an unofficial flight endurance record for a fuel-cell powered
flight of 23 hours 17 minutes. The electric fuel cell propulsion
system onboard the Ion Tiger has the low noise and signature of
a battery powered UAV, while taking advantage of hydrogen, a
high-energy fuel. Fuel cells create an electrical current when
they convert hydrogen and oxygen into water, with only water and
heat as byproducts. The 550 watt (0.75 horsepower) fuel cell
onboard the Ion Tiger has about 4 times the efficiency of a
comparable internal combustion engine and the system provides 7
times the energy in the equivalent weight of batteries. The Ion
Tiger weighs approximately 37 pounds and carries a 4 to 5 pound
payload. Small UAVs are growing in importance for naval
missions, as they provide capabilities ranging from surveillance
collection to communication links. It is now possible to do long
endurance missions with the Ion Tiger thus allowing a large
cruise range and reducing the number of daily launches and
landings, while saving time and effort on the part of the Naval
Crew.
A 50 million year old skull reveals that huge
birds with a five metre wingspan once skimmed across the waters
that covered what is now London, Essex., and north Kent. These
giant ocean-going relatives of ducks and geese had a rather
bizarre attribute for a bird: their beaks were lined with bony
teeth.
The pantomime season may be over, but this new
fossil from the Isle of Sheppey is giving ‘Mother Goose’ an
entirely new meaning. The skull belongs to
Dasornis, a
bony-toothed bird, or pelagornithid, and was discovered in the
London Clay,
which lies under much of London, Essex and north Kent. With a 5
metre wingspan, these huge birds were similar to Albatross in
their way of life. Albatross have the largest
wingspan of any living bird, but that of
Dasornis was over a metre and a half greater. The strange thing
about them was that they had sharp tooth-like projections along
the cutting edges of the beak. This may have been linked to its
diet. for Dasornis probably skimmed across the surface of the
sea, snapping up fish and squid on the wing. With only an
ordinary beak these would have been difficult to keep hold of,
and the pseudo-teeth probably evolved to prevent meals slipping
away.
There were very few sightings of marine
creatures during December, and these were all from around West
Penwith from Carbis Bay to the Minack, and what’s more all from
one dedicated watcher except for one report, of Bottlenose
Dolphin, off St Ives. There were pods of 35 to 45 Common
Dolphins on the 1st of the month at The Runnelstone and another
pod of 20 to 30, with juveniles at the Runnelstone on the 2nd.
All the other 9 sightings were of single or small groups of
Harbour Porpoises.
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