Growth dynamics of Phaeocystis antarctica-dominated plankton assemblages from the Ross Sea

Walker O. Smith, Craig A. Carlson, Hugh W. Ducklow, Dennis A Hansell

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Large-volume experiments were conducted using natural seawater assemblages collected in the southern Ross Sea during austral spring 1994 and summer 1995 to assess the carbon and nitrogen exchanges among phytoplankton, bacteria and dissolved organic carbon pools, and to compare the elemental partitioning in these experimental enclosures with those observed in situ. Large concentrations of particulate matter were produced in these enclosures, which were at all times dominated by the colonial haptophyte Phaeocystis antarctica. Particulate organic carbon concentrations exceeded 200 μmol l-1 at the end of the experiment. Bacterial carbon comprised only a small (<1%) fraction of the particulate carbon, but bacteria grew at 0.15 to 0.3 d-1 and were not limited by bacteriovores. Nutrient levels decreased concomitantly with POC increases, and nitrate was reduced to undetectable levels. Dissolved organic carbon (DOC) levels remained low (less than 50 μM) while nutrients were present, but increased dramatically (to more than 200 μM) after nitrate was depleted. Growth rates calculated from changes in particulate matter concentrations were slightly below the predicted maximum based on temperature. Field studies, however, showed no depletion of nitrate, similar levels of particulate organic carbon to those found during exponential growth, low levels of DOC, and relatively low levels of bacterial biomass. It appears that P. antarctica in the Ross Sea does not produce large amounts of DOC during nutrient-replete growth; furthermore, because macronutrients are rarely, if ever, depleted where P. antarctica is dominant in the Ross Sea, it is likely that much of the carbon generated during its growth remains in the particulate pool.

Original languageEnglish (US)
Pages (from-to)229-244
Number of pages16
JournalMarine Ecology Progress Series
Volume168
StatePublished - Jul 9 1998
Externally publishedYes

Fingerprint

dissolved organic carbon
Antarctica
plankton
particulates
carbon
nitrates
particulate organic carbon
nitrate
nutrient
particulate matter
nutrients
bacterium
bacteria
carbon sinks
partitioning
seawater
experiment
phytoplankton
Phaeocystis
sea

Keywords

  • Antarctica
  • Bacteria
  • Carbon
  • Dissolved organic
  • Nitrogen
  • Particulate organic
  • Phaeocystis
  • Phytoplankton

ASJC Scopus subject areas

  • Aquatic Science
  • Ecology

Cite this

Growth dynamics of Phaeocystis antarctica-dominated plankton assemblages from the Ross Sea. / Smith, Walker O.; Carlson, Craig A.; Ducklow, Hugh W.; Hansell, Dennis A.

In: Marine Ecology Progress Series, Vol. 168, 09.07.1998, p. 229-244.

Research output: Contribution to journalArticle

Smith, Walker O. ; Carlson, Craig A. ; Ducklow, Hugh W. ; Hansell, Dennis A. / Growth dynamics of Phaeocystis antarctica-dominated plankton assemblages from the Ross Sea. In: Marine Ecology Progress Series. 1998 ; Vol. 168. pp. 229-244.
@article{d955a00c16e94d3b96cee31c97ed1054,
title = "Growth dynamics of Phaeocystis antarctica-dominated plankton assemblages from the Ross Sea",
abstract = "Large-volume experiments were conducted using natural seawater assemblages collected in the southern Ross Sea during austral spring 1994 and summer 1995 to assess the carbon and nitrogen exchanges among phytoplankton, bacteria and dissolved organic carbon pools, and to compare the elemental partitioning in these experimental enclosures with those observed in situ. Large concentrations of particulate matter were produced in these enclosures, which were at all times dominated by the colonial haptophyte Phaeocystis antarctica. Particulate organic carbon concentrations exceeded 200 μmol l-1 at the end of the experiment. Bacterial carbon comprised only a small (<1{\%}) fraction of the particulate carbon, but bacteria grew at 0.15 to 0.3 d-1 and were not limited by bacteriovores. Nutrient levels decreased concomitantly with POC increases, and nitrate was reduced to undetectable levels. Dissolved organic carbon (DOC) levels remained low (less than 50 μM) while nutrients were present, but increased dramatically (to more than 200 μM) after nitrate was depleted. Growth rates calculated from changes in particulate matter concentrations were slightly below the predicted maximum based on temperature. Field studies, however, showed no depletion of nitrate, similar levels of particulate organic carbon to those found during exponential growth, low levels of DOC, and relatively low levels of bacterial biomass. It appears that P. antarctica in the Ross Sea does not produce large amounts of DOC during nutrient-replete growth; furthermore, because macronutrients are rarely, if ever, depleted where P. antarctica is dominant in the Ross Sea, it is likely that much of the carbon generated during its growth remains in the particulate pool.",
keywords = "Antarctica, Bacteria, Carbon, Dissolved organic, Nitrogen, Particulate organic, Phaeocystis, Phytoplankton",
author = "Smith, {Walker O.} and Carlson, {Craig A.} and Ducklow, {Hugh W.} and Hansell, {Dennis A}",
year = "1998",
month = "7",
day = "9",
language = "English (US)",
volume = "168",
pages = "229--244",
journal = "Marine Ecology - Progress Series",
issn = "0171-8630",
publisher = "Inter-Research",

}

TY - JOUR

T1 - Growth dynamics of Phaeocystis antarctica-dominated plankton assemblages from the Ross Sea

AU - Smith, Walker O.

AU - Carlson, Craig A.

AU - Ducklow, Hugh W.

AU - Hansell, Dennis A

PY - 1998/7/9

Y1 - 1998/7/9

N2 - Large-volume experiments were conducted using natural seawater assemblages collected in the southern Ross Sea during austral spring 1994 and summer 1995 to assess the carbon and nitrogen exchanges among phytoplankton, bacteria and dissolved organic carbon pools, and to compare the elemental partitioning in these experimental enclosures with those observed in situ. Large concentrations of particulate matter were produced in these enclosures, which were at all times dominated by the colonial haptophyte Phaeocystis antarctica. Particulate organic carbon concentrations exceeded 200 μmol l-1 at the end of the experiment. Bacterial carbon comprised only a small (<1%) fraction of the particulate carbon, but bacteria grew at 0.15 to 0.3 d-1 and were not limited by bacteriovores. Nutrient levels decreased concomitantly with POC increases, and nitrate was reduced to undetectable levels. Dissolved organic carbon (DOC) levels remained low (less than 50 μM) while nutrients were present, but increased dramatically (to more than 200 μM) after nitrate was depleted. Growth rates calculated from changes in particulate matter concentrations were slightly below the predicted maximum based on temperature. Field studies, however, showed no depletion of nitrate, similar levels of particulate organic carbon to those found during exponential growth, low levels of DOC, and relatively low levels of bacterial biomass. It appears that P. antarctica in the Ross Sea does not produce large amounts of DOC during nutrient-replete growth; furthermore, because macronutrients are rarely, if ever, depleted where P. antarctica is dominant in the Ross Sea, it is likely that much of the carbon generated during its growth remains in the particulate pool.

AB - Large-volume experiments were conducted using natural seawater assemblages collected in the southern Ross Sea during austral spring 1994 and summer 1995 to assess the carbon and nitrogen exchanges among phytoplankton, bacteria and dissolved organic carbon pools, and to compare the elemental partitioning in these experimental enclosures with those observed in situ. Large concentrations of particulate matter were produced in these enclosures, which were at all times dominated by the colonial haptophyte Phaeocystis antarctica. Particulate organic carbon concentrations exceeded 200 μmol l-1 at the end of the experiment. Bacterial carbon comprised only a small (<1%) fraction of the particulate carbon, but bacteria grew at 0.15 to 0.3 d-1 and were not limited by bacteriovores. Nutrient levels decreased concomitantly with POC increases, and nitrate was reduced to undetectable levels. Dissolved organic carbon (DOC) levels remained low (less than 50 μM) while nutrients were present, but increased dramatically (to more than 200 μM) after nitrate was depleted. Growth rates calculated from changes in particulate matter concentrations were slightly below the predicted maximum based on temperature. Field studies, however, showed no depletion of nitrate, similar levels of particulate organic carbon to those found during exponential growth, low levels of DOC, and relatively low levels of bacterial biomass. It appears that P. antarctica in the Ross Sea does not produce large amounts of DOC during nutrient-replete growth; furthermore, because macronutrients are rarely, if ever, depleted where P. antarctica is dominant in the Ross Sea, it is likely that much of the carbon generated during its growth remains in the particulate pool.

KW - Antarctica

KW - Bacteria

KW - Carbon

KW - Dissolved organic

KW - Nitrogen

KW - Particulate organic

KW - Phaeocystis

KW - Phytoplankton

UR - http://www.scopus.com/inward/record.url?scp=2642682399&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2642682399&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:2642682399

VL - 168

SP - 229

EP - 244

JO - Marine Ecology - Progress Series

JF - Marine Ecology - Progress Series

SN - 0171-8630

ER -