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A test of the ashߚfree dry weight technique on the developmental stages of Patiriellaspp. (Echinodermata: Asteroidea)
Author(s) -
Moreno Guillermo,
Selvakumaraswamy Paulina,
Byrne Maria,
HoeghߚGuldberg Ove
Publication year - 2001
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2001.46.5.1214
Subject(s) - dry weight , zoology , benthic zone , seawater , biology , plankton , distilled water , human fertilization , environmental chemistry , chemistry , botany , ecology , chromatography , anatomy
Determination of the ashߚfree dry weight (AFDW) of marine specimens requires samples to be rinsed, soaked, and centrifuged. Problems associated with this technique were examined with the developmental stages of seastar species ( Patiriella ) with different modes of development. The influence of three rinsing solutions (ammonium formate [AF], filtered seawater [FSW], and reverse osmosis water [RO]) was assessed. The hypothesis that the AFDW technique is a measure of organic material was addressed by drying inorganic salts. Developmental stages of Patiriella calcar rinsed in FSW were twice as heavy as those rinsed in RO or AF, indicating that samples should be rinsed in RO or AF before weighing. Soaking treatments had a significant effect on the AFDW of samples of P. calcar (planktonic developer), indicating that the rinsing period should be brief. Zygotes of Patiriella regularis (planktonic developer) were significantly heavier than ova or gastrulae, regardless of treatment. In contrast, there were no significant differences in the AFDW of any stages or treatments of Patiriella exigua (benthic developer). This may be due to the presence of a modified fertilization envelope, which protects these benthic embryos. Inorganic salts with water of crystallization and FSW lost 20–75% and 14% of their dry weight, respectively, after ashing. We propose that salt ions may retain water, which does not evaporate during drying but is lost during ashing, resulting in the overestimation of sample AFDW. If a similar process occurs in the developmental stages of marine invertebrates, changes in the intracellular ionic composition through development may result in inaccurate estimates of biomass.