Dataset: Biomass
Deployment: W0605B

Methods for Phototrophic and Heterotrophic Plankton Taxa Sampling,

Preservation, Enumeration and Biomass Estimation

(Modified from Frame and Lessard, in press)



Biomass of phytoplankton and microzooplankton taxa groups were measured

in the initial samples for dilution experiments off the Washington and

Oregon coasts taken during four RISE cruises 2004-2006.



Replicate samples for phytoplankton and microzooplankton identification,

enumeration, and sizing were preserved with either acid Lugol's (5% final

conc.) or gluteraldehyde (0.5% final conc.). Gluteraldehyde-fixed samples

were stained with DAPI and proflavin, then filtered onto 0.8µm and 0.2µm

black polycarbonate membranes (Lessard and Murrell 1996). Slides were

stored frozen until analysis onshore.



Microscope counts

Known volumes of the Lugols-preserved samples were settled in counting

chambers for enumeration of ciliates (including mixotrophs), diatoms and

larger dinoflagellates. Counts were performed on a Zeiss inverted microscope

at 250x magnification. Glutarldehyde-preserved samples on 0.8µm filters

were examined with a Zeiss standard epifluorescence microscope at 400x

magnification for enumeration of microphytoplankton including photosynthetic

dinoflagellates (typically <40µm), cryptophytes, and an unidentified

raphidophyte. Samples on the 0.2µm filters were examined at 1000x

magnification for cyanobacteria, picoeukaryotes (<2 µm) and photosynthetic

and heterotrophic nanoflagellates (>2-10µm).



Biomass estimates

Picoplankton (cyanobacteria and picoeukaryotes) were sized using images

taken with a QImaging Retiga EX charged coupled device (CCD) camera and

Image Pro Plus software. Dimensions of all other cells were measured

using a computer-aided digitizing system (Roff and Hopcroft 1986).

Cell volumes were calculated using appropriate geometric formulas and

carbon was calculated using the carbon to volume equations of Menden-Deuer

and Lessard (2000) for diatoms, nanoplankton and dinoflagellates, and of

Worden et al. (2004) for picoplankton. Ciliate carbon was estimated using

the conversion from Putt and Stoecker (1989).





References for further details:

Lessard, E.J. and M.C. Murrell (1996), Distribution, abundance and size composition

of heterotrophic dinoflagellates and ciliates in the Sargasso Sea near Bermuda,

Deep Sea Research Part I, 43(7), 1045-1065.



Frame, E.R. Frame and E.J. Lessard. Does the Columbia River Plume influence phytoplankton

community structure along the Washington and Oregon coasts? In press. J. Geophysical Res.



Menden-Deuer, S., and E. J. Lessard (2000), Carbon to volume relationships for

dinoflagellates, diatoms, and other protist plankton. Limnol. Oceanogr., 45, 569-579.



Putt, M., and D. K. Stoecker. 1989. An experimentally determined carbon:volume ratio

for marine "oligotrichous" ciliates from estuarine and coastal waters.

Limnol. Oceanogr. 34: 1097-1103.



Roff, J. C. and R. R. Hopcroft (1986), High precision microcomputer based measuring

system for ecological research, Can. J. Fish. Aquat. Sci., 43, 2044-2048.



Worden, A.Z., J.K. Nolan, and B. Palenik (2004), Assessing the dynamics and ecology

of marine picophytoplankton: the importance of the eukaryotic component,

Limnol. Oceanogr., 49(1), 168-179.