concentrations of abundant zooplankton. 



Nano- and microplankton samples are derived from shipboard Niskin bottle samples. (1) 

 Preparations for plankton composition and biomass require 5 minutes/sample aboard ship but 1 -2 

 hours each to analyze back in the lab. Thus the scales of sampling are purely labor-dependent. 

 Repetitive sampling of stations at 5 km intervals can be accomplished. (2) Experimental 

 incubations to measure grazing rates require 24 hr. Experience in JGOFS indicates that two 

 experiments per day (i.e., two different depths at one station or one depth at two stations, 

 depending upon whether the ship is in transect- or time-series mode) is possible, depending upon 

 labor constraints (bunk space). (3) Immunochemical assays of predation on micro zooplankton 

 require vertical profiles of predator and prey. The time frames for sample collection and analyses 

 are as in (1), while the post-cruise laboratory procedures are somewhat more time consuming. 

 A 5 km spaced cube could be sampled but less frequently than (1), e.g, once every 3-4 days. 



METHODS AND PLATFORMS 



Sampling requires capture of water parcels from shipboard platforms. Grazing of 

 phytoplankton (primary production) and other small heterotrophic plankton will be measured 

 aboard ship from incubation experiments, using changes in algal pigments (HPLC, fluorometry) 

 and changes in carbon biomass, composition, and size distribution of the plankton communities. 

 Analysis of plankton carbon will be conducted ashore using a state-of-the-art color imaging 

 system and inverted microscopy. Ingestion of microzooplankton carbon by macrozooplankton 

 using immunoassays will also be determined ashore from field-collected samples. 



STRENGTHS AND LIMITATIONS OF PROPOSED RESEARCH 



Metazooplankton : 



Strengths. Sophisticated feeding rate quantifications are needed to determine actual feeding rates 

 of abundant metazooplankton. Since it is obvious that nearly every stage of a copepod is 

 potentially an omnivore (being able to feed on autotrophs and heterotrophs), respective 

 experiments quantifying such performances need to be made, even if they would be time- 

 consuming. Simultaneously, with sophisticated feeding studies, we will determine 

 metazooplankton growth rates. 



Limitations. The traditional microscopic analysis of net-collected metazooplankton is laborious 

 and time-consuming. They need to be made until we possess the technology to quantify 

 respective genera and stages directly in situ, or from flow-by samples on board ship. They are 

 needed because biomass does not distinguish between calanoid and cyclopoid copepods, tunicates, 

 carnivorous coelenterates and chaetognaths, each of these taxa contributing in a different manner 

 to carbon flow in the ocean. 



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