An experiment was undertaken at Farol Island,
Brazil, to examine colonization of bare aluminium surfaces
by microbes and meiofauna. It was hypothesized
that a primary source of meiofaunal colonists was sediment
resuspended during upwelling events, two of
which occurred during the experiment. Microbial biofilms
formed on the experimental substrata within 1 day,
and continued to develop throughout the experimental
period. Among meiofaunal groups copepods also appeared
on the first day, and nematodes on the second.
Meiofaunal community structure developed in three
main phases: an initial phase of 2 days, characterized by
low abundances of copepods; a second phase during the
first upwelling period characterized by higher abundances
of copepods and also by turbellarians; and a
third phase from day 13 onwards characterized by relatively
stable abundances of a range of taxa including
copepods, cirripedes, nematodes and ostracods. Nematode
assemblages also developed in three phases, but
with different timings coinciding with upwelling events:
an initial phase, from the beginning of the experiment to
day 9, characterized by few species and low (or no)
abundances; a second phase following the first upwelling
characterized by moderate abundances of Chromadorina,
Chromadorella, Daptonema and Euchromadora sp. 3;
a third phase following the second upwelling period
(from day 26 onwards) in which Daptonema disappeared
and the assemblage was characterized by moderate to
high abundances of Euchromadora (species 1 and 2) and
Chromadorella. Although shifts in nematode assemblage
structure coincided with upwelling events no evidence
was found for sediments being the primary source of
colonizers on the aluminium substrata, in contrast to
our hypothesis.