For dissolved nitrogen, phosphorus and silicate, six
10ml subsamples were filtered through sterile polycarbonate filters with 0.2lm pore size, and the particle-free
water frozen at18°C for later analysis.For particulate
nutrients, chlorophyll and phaeopigments, duplicate
subsamples (250ml, and 100ml respectively) were filtered onto pre-combusted 25 mm Whatman GF/F filters
(0.2lm nominal pore size) at low vacuum (8kPa). Filters were then wrapped into pre-combusted aluminium
foil,and frozen until further analysis.Dry weight of suspended solids was determined from duplicate 1000ml
water samples filtered through preweighed 45 mm polycarbonate filters with 0.4
l
m pore size. Surface salinity
was determined from a 500ml water sample stored in
airtight bottles at room temperature. In the laboratory,
the samples were analysed following standard proce-
dures