A new matrix factorization program 'CHEMTAX was used to ~nterpret high-performance hquid chromatography (HPLC) pigment data from a transect between Prydz Bay Antarct~ca and Australla dunng March 1987 The program calculated the abundance of diatoms dinoflagellates haptophytes resembling Emiliania huxleyl haptophytes resembling P h a e o c j~s t~s antarctlca cyanobacteria prasinophytes, chlorophytes and cryptophytes along the transect The results were compared with those of microscopy and particle size analysis The transect was dominated by small cells particle size analysis showed that particles < 2 pm represented 27 to 44 Oh of the total by number while particles 2 to 20 pm represented 55 to 68% Particles >20 pm never represented more than 3 % by number but constituted 57 to 93 % of the total v o l u n~e Microscop~c analysis showed that small flagellates were the most abundant cells along the transect wlth a 5-fold increase In abundance at 47"s Numbers of dlatoms (most <20 pm in size) Increased markedly south of the Polar Front, correlating with the concentration of silica D~noflagellate numbers were relatively constant along the transect although somewhat higher north of 5 0 " s Those <20 pm in size were most numerous and accounted for most of the latltudinal vanation Interpretation of HPLC pigment data using the CHEM TAX program was consistent with microscopical analysis The computed abundances of diatoms and dinoflagellates correlated more strongly with the numbers of small (<20 pm) dlatoms and d~noflagellates, respectively than with large ones Computed cyanobactenal abundances correlated well wlth microscopical observations except for small errors where cyanobactena were absent probably d u e to m~sallocation of zeaxanthln from chlorophvtes and praslnophytes The program was able to distinguish 2 populations of haptophytes along the transect representing Phdeocystis antarctlca and coccol~thophonds even though their pigment compositions were qualitatively (though not quantitatively) Identical It also indicated the separate distributions of chlorophytes and prasinoxarithin-containing praslnophytes, and showed the presence of cryptophytes where none were observed by microscopy

Abstract.A global pigment database consisting of 35 634 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 17 % and 19 % stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophylls a and b, 19'-butanoyloxyfucoxanthin, 19'-hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities, where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: http://doi.pangaea.de/10. 1594/PANGAEA.793246.

Abstract. A global pigment database consisting of 37 103 pigment suites measured by high performance liquid chromatography was assembled in support of the MARine Ecosytem DATa (MAREDAT) initiative. These data originate from 136 field surveys within the global ocean, were solicited from investigators and databases, compiled, and then quality controlled. Nearly one quarter of the data originates from the Laboratoire d'Océanographie de Villefranche (LOV), with an additional 20% and 17% stemming from the US JGOFS and LTER programs, respectively. The MAREDAT pigment database provides high quality measurements of the major taxonomic pigments including chlorophyll a and b, 19'butanoyloxyfucoxanthin, 19'hexanoyloxyfucoxanthin, alloxanthin, divinyl chlorophyll a, fucoxanthin, lutein, peridinin, prasinoxanthin, violaxanthin and zeaxanthin, which may be used in varying combinations to estimate phytoplankton community composition. Quality control measures consisted of flagging samples that had a total chlorophyll a concentration of zero, had fewer than four reported accessory pigments, or exceeded two standard deviations of the log-linear regression of total chlorophyll a with total accessory pigment concentrations. We anticipate the MAREDAT pigment database to be of use in the marine ecology, remote sensing and ecological modeling communities where it will support model validation and advance our global perspective on marine biodiversity. The original dataset together with quality control flags as well as the gridded MAREDAT pigment data may be downloaded from PANGAEA: doi:10.1594/PANGAEA.793246.