Bacterivory in eutrophic Lake Oglethorpe, Georgia, was determined by direct observation of tracer particle uptake by all members of the planktonic community. Heterotrophic flagellates dominated grazing at all times, accounting for 49-8 1% of grazing on an areal basis and up to 98% of grazing at some depths. Pigmented (mixotrophic) flagellates were major grazers during winter and spring blooms, ...

• In situ indices of iron limitation in phytoplankton • Phytoplankton biomass and systematics with flowcytometry and microscopy North American scientists discussed the fundamental questions and observational details of proposed comparative studies of ecological processes in the upper waters of the oceanic subarctic Pacific. The physical setting of the subarctic Pacific was well described by Fav...

During the European Iron Fertilisation Experiment (EIFEX), performed in the Southern Ocean, we investigated the reactions of different phytoplankton size classes to iron fertilization, applying measurements of size fractionated pigments, particulate organic matter, microscopy, and flow cytometry. Chlorophyll a (Chl a) concentrations at 20-m depth increased more than fivefold following fertiliza...

Population interactions between nanoplankton and bacteria were investigated by means of long (ca, 5 day) incubations of prescreened seawater samples. Evidence is presented to show that population development is controlled by the predation of larger organisms on smaller ones. The development of the bacterial populations seems to be totally controlled by predation by nano-sized organisms (flagell...

Mixotrophy among planktonic eukaryotic organisms is broadly defined as the combined use of photosynthetic and heterotrophic nutrition within a single organism. The conventional view of species as either phototrophic (capable of producing energy and carbon for growth using only inorganic compounds and light) or heterotrophic (wholly dependent on preformed organic material for nutrition) is a pre...

8 annually degasses about 1 gigatonne (10 tonnes) of CO2 (ref. 3), equivalent to 20 per cent of current anthropogenic output. The regression lines and intercepts of dissolved inorganic carbon, silicate and nitrate concentrations, measured in the upper 200 m of the EUZ, indicate that silicate availability regulates both carbon and nitrate uptake and fate. The slope of the highly significant regr...

The Dinarides, together with the Albanides and Hellenides, preserve stratigraphic successions derived from eastern margin of Adriatic microplate remnants ophiolites obducted Maliac-Vardar branch Neotethys Ocean. main stages in Mesozoic geodynamic history are: 1) rifting leading to opening Maliac Ocean Late Anisian, 2) onset an east-dipping intra-oceanic subduction Early-Middle Jurassic sea-floo...

We describe a database of the single-particle optical properties cd marine microbial particles. This database includes representatives from five classes of particles: viruses (VIR), heterotrophic bacteria (BAC), cyanobacteria (CYA), small nanoplanktonic diatoms (DIA), and nanoplanktonic chlorophytes (CHLO). The optical properties of VIR, whose mean size is 0.07 pm, were determined from Mie scat...

Phytoplankton samples were collected at Bahı́a Engaño, Chubut, Argentina (438S, 658W) at different times of the year to assess the combined effect of ultraviolet radiation (UVR, 280–400 nm) and vertical mixing (i.e., the depth of the upper mixed layer, UML) on photosynthesis. Samples were exposed to fixed and fluctuating radiation regimes in an illuminated chamber at 158C (photosynthetically ava...

CHEMTAX is a matrix factorization program used to derive taxonomic structure of phytoplankton from photosynthetic pigment ratios. The program was originally developed from and applied to the analysis of oceanic phytoplankton assemblages. We found that application of the original CHEMTAX reference matrix to southeastern United States estuarine systems produced inaccurate results, as verified by ...