Abstract

Diatoms are important primary producers within pelagic, benthic end epiphytic communities and their siliceous frustule leads to rapid sinking to the sediment. As a consequence, diatoms play a critical role in nutrient and carbon cycles in shallow and deep water environments. In this study, benthic nutrient and gas fluxes, water column and sediment properties were studied in a coastal lagoon of south-eastern Australia to identify control mechanisms coupling benthic and pelagic processes, in particular, how nutrients become fractionated by processes affecting benthic nutrient fluxes. During late spring, the water column of St. Georges Basin was oligotrophic, primary production was likely P limited and the phytoplankton community was dominated by cyanophytes. Molar ratios of TCO2 : Si benthic fluxes, however, were equal to the molar composition of diatoms suggesting that diatoms preferentially sink and deliver the most labile organic matter fraction to the sediment. The congruent release of Si and C implies a coupling of processes mobilizing Si and C. It is argued that extracellular polymeric substances surrounding the silicious frustule are the primary labile organic matter fraction and their rate of mineralization limits the dissolution of the silicious frustule. As decomposing biomass in sediments lead to net N2-production and very efficient burial of P, the fate of diatoms significantly contribute to the removal of bioavailable nutrients. High DIN:DIP benthic flux ratios of 290 to 900 promote P limitation particularly in shallow water bodies with long water residence times.
Google map showing geographic bounding box with values North bound -35.08 East bound 150.65 West bound 150.53 South bound -35.16
Related Links
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays

Product Type/Sub Type

dataset - External Publication - Scientific Journal Paper

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2007

Product Type

dataset

Topic Category

geoscientificInformation

Keywords

External Publication
Scientific Journal Paper
marine
AEM
geochemistry
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-35.08
East bound
150.65
West bound
150.53
South bound
-35.16

Lineage

Unknown

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a05f7892-cee9-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2006-08-18

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Related Links
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays