Particulate and dissolved aluminum and titanium in the upper water column of the Atlantic Ocean

This study investigates the oceanic behavior of the lithogenic trace elements Al and Ti in the upper 200 m of the Atlantic Ocean. The distribution of both metals in the dissolved and particulate phases was assessed along an E-W transect in the eastern tropical North Atlantic (December 2009) and along a meridional Atlantic transect (April-May 2010). The surface water concentrations of particulate and dissolved Al and Ti reflected the previously observed pattern of atmospheric inputs into the Atlantic Ocean. Subsurface minima at stations with pronounced fluorescence maxima were observed, suggesting a link between biological productivity and the removal of both dissolved and particulate Al and Ti. This may include uptake mechanisms, adsorption and aggregation processes on biogenic particle surfaces and the formation of large, fast sinking biogenic particles, e.g., fecal pellets. Residence times in the upper water column (100 m) of the tropical and subtropical North Atlantic were estimated to range in the order of days to weeks in the particulate phases (Al: 3-22 days, Ti: 4-37 days) and were 0.9-3.8 years for Al and 10-31 years for Ti in the dissolved phases. Longer residence times in both phases in the South Atlantic are consistent with lower biological productivity and decreased removal rates. In the upper water column, Al was predominantly present in the dissolved form, whereas Ti mostly occurred in the particulate form. Largest deviations in the partition coefficients between the particulate and dissolved phases were found in the surface waters, together with excess dissolved Al over Ti compared to the crustal source. This likely reflects elevated dissolution of Al compared to Ti from atmospheric mineral particles.

Marine Zooplankton of Southern Britain - Part 1: Radiolaria, Heliozoa, Foraminifera, Ciliophora, Cnidaria, Ctenophora, Platyhelminthes, Nemertea, Rotifera and Mollusca. Occasional Publication of the Marine Biological Association 25

This series of three guides (of which this is Part 1) collates taxonomic identification information for the zooplankton groups recorded off south-west Britain , primarily for local identification and training purposes. However, because prevailing currents also bring oceanic zooplankton into the English Channel , the range of species sampled off Plymouth covers the majority found over the shallower parts of northern European continental shelf (excluding the Mediterranean Sea ), so the guides should be more widely useful and hopefully make tackling zooplankton identification easier for a wider audience. The commonest truly planktonic species and the most widely studied groups are covered in most detail, but some information is also included on benthic, epibenthic and parasitic species that are sampled occasionally. For all groups there is at least information on their morphology, guidance on their identification and bibliographies giving identification resources.