Document Type

Article

Publication Title

Marine Ecology-Progress Series

Publication Date

6-1-1996

First Page

227

Last Page

234

Issue Number

40546

Volume Number

136

Abstract/ Summary

The rate of proteolysis of amino acids was used to assess the nutritional lability of various materials making up estuarine seston in 3 Maine, USA, estuaries. Physical separations of subcellular fractions of phytoplankton cells led to higher proteolysis rate constants for the cytoplasmic fraction (>1.2 h(-1)) than for the membrane fraction (0.2 to 1 h(-1)). Whole cells, copepod fecal pellets, bottom sediments, and estuarine seston had overlapping ranges of rate constants of 0.17 to 1.3 h(-1), which were indistinguishable from one another. Protein pools in the seston of these estuaries throughout the seasons were dominated by phytoplankton production and its fresh detrital products. Inverse relationships between proteolysis rate constants for estuarine seston and the ratios of pheopigments to chlorophyll indicates that the average lability of seston decreases with the disappearance of cytoplasmic material in suspension. This kinetic approach to the quality of food resources implies the existence of different pools of digestible protein for estuarine heterotrophs with different gut residence times. Preferential enrichment of membrane components in sestonic detritus may result from the differential lability of proteins in cytoplasm versus membrane components of cells.

Citation/Publisher Attribution

Laursen AK, Mayer LM, Townsend DW. Lability of Proteinaceous Material in Estuarine Seston and Subcellular Fractions of Phytoplankton. Marine Ecology-Progress Series. 1996;136: 227-234.

Publisher Statement

Copyright 1996 Inter-Research.

DOI

10.3354/meps136227

Version

publisher's version of the published document

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