Dataset: Diatom contribution to benthic GPP - Silica and Nitrogen analyses

Name: Silica and nitrogen analyses from incubation experiments conducted using seagrass cores from 1m depth in Grand Bay in 2017.
Published: 2020-08-10
Keywords: ecosystem production, epiphytes, diatoms, microphytobenthos, northern Gulf of Mexico, seagrass bed, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.819975.1

Spatial Extent: N:30.383174 E:-88.312561 S:30.383174 W:-88.312561

Temporal Extent: 2017-06-28 - 2017-07-31

Project:

The biotic and abiotic controls on the Silicon cycle in the northern Gulf of Mexico (CLASiC)

Principal Investigator:

Jeffrey W. Krause (Dauphin Island Sea Lab, DISL)

Co-Principal Investigator:

Just Cebrian (Mississippi State University, MSU)

Contact:

Erin Cox (University of New Orleans, UNO)

BCO-DMO Data Manager:

Christina Haskins (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2020-08-10

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Silica and nitrogen analyses from incubation experiments conducted using seagrass cores from 1m depth in Grand Bay in 2017.

Abstract:

We report an assessment for determining the contribution by diatoms to community productivity and respiration within a coastal benthic ecosystem with multiple autotrophs. During summer, cores of open sediment and seagrass habitat were collected from a lagoon within the Northern Gulf of Mexico. Cores were maintained in an outdoor mesocosm. Germanic acid, an inhibitor of diatom cell division, was added to half the cores and quantification of production and respiration was done. Inhibition of diatoms reduced benthic productivity within the seagrass habitat. 71 to 83% of production was attributable to diatoms and this contribution moved the benthic system into net autotrophy. Diatom contribution to production in other habitat-community components was more variable (varied from 0 to 86%). Findings underscore the ecological importance of diatoms as producers in seagrass beds, the role of seagrasses in maintaining productivity, and infer that diatoms may have similar contributions in other aquatic vegetated habitats.

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2020-08-10	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.819975.1	2020-08-11

Methods & Sampling

Three repeated experimental trials were done in summer months. Thirty-two cores (27 cm diameter, 14 cm depth) were collected from 50 m2 area of seagrass bed at 1 m depth on: June 28, July 12 and July 26, 2017 for trials 1-3, respectively. On each date, 16 cores were collected from seagrass habitat in pairs. Another 16 cores were collected from open sediment (OS) habitat. Extracted, paired cores were placed upright into an open-top plastic tub (49 x 33 x 42 cm) to produce eight tubs of each habitat.

Tubs were transported to Dauphin Island Sea Lab (~30-minute drive) filled with seawater (to core depth of 16 cm) pumped from Mobile Bay (20 km, east of site) and arranged in four blocks within an outdoor mesocosm. Each block contained two tubs of each habitat. After two days, a diatom-specific inhibitor (3 µM solution of germanic acid, i.e. Ge treatment) was randomly added to water, i.e. two tubs per block, one of each habitat type. Germanium (Ge) at high Ge/Si ratios (> 0.01) prevents formation of siliceous cell wall (Azam and Chisholm 1976). We added 3 µM solution and allowed two days for Ge incorporation.

Metabolism measurements:

Two days after, we quantified productivity and respiration from changes in oxygen content within 2-3 hour incubations of chambers and bottles following methods in Anton et al. (2009).

Nitrogen and Silica:

At end of incubation, 100 mL of water from each clear chamber was filtered through 47 mm Whatman glass fiber filter. Filtered water was analyzed for total dissolved nitrogen (TDN) and nitrate+nitrite (NO3-+NO2-) colorimetrically using Skalar autoanalyzer (Dzwonkowski et al. 2017), and for dissolved silicic acid (Si(OH)4) using a manual colorimetric method (Krause et al. 2009).

Statistical analyses:

A series of two-way ANOVAs with trial and treatment as fixed factors were used to test for differences in environment in both habitats.

Data Processing Description

Excel, Sigma Plot

BCO-DMO Data Manager Processing Notes:
* added a conventional header with dataset name, PI name, version date
* modified parameter names to conform with BCO-DMO naming conventions
* blank values in this dataset are displayed as "nd" for "no data." nd is the default missing data identifier in the BCO-DMO system. Added ND as a missing data identifier.
* removed all spaces in headers and replaced with underscores
* removed all units from headers
* converted dates to ISO Format yyyy-mm-dd
* set Types for each data column

Data Files

File
ni_dsi.csv (Comma Separated Values (.csv), 5.32 KB) MD5:4291c321eee467dd0d840c95a79c4621 Primary data file for dataset ID 819975

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1558957

Deployments

None available yet

Instruments

Multi Parameter Portable Meter

Supplied Name: HQ30d, Hach, Loveland, Colorado, USA

Supplied Description:

Instrument Type

Generic Name: Multi Parameter Portable Meter

Generic Description:

An analytical instrument that can measure multiple parameters, such as pH, EC, TDS, DO and temperature with one device and is portable or hand-held.

Nutrient Autoanalyzer

Supplied Name: Skalar autoanalyzer

Supplied Description:

Instrument Type

Generic Name: Nutrient Autoanalyzer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB04/

Generic Description:

Nutrient Autoanalyzer is a generic term used when specific type, make and model were not specified. In general, a Nutrient Autoanalyzer is an automated flow-thru system for doing nutrient analysis (nitrate, ammonium, orthophosphate, and silicate) on seawater samples.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
Analysis_ID	name given to the water sample for analysis	unitless	sample
Sample_ID	name of the core water came from	unitless	sample
Collection_Date	date the core was collected from field site	yyyy-mm-dd	date
Ge_Addition_Date	date Ge was added to cores	yyyy-mm-dd	date
Experimental_Trial_Date	date of the incubation	yyyy-mm-dd	date
Trial	indicates whether it is trial 1, 2, or 3	unitless	exp_type
Core_Taken_From	indicates where the core was taken from	unitless	exp_type
Ge_Control_Treatment	indicates whether the sample came from a core given Ge or a control (no Ge added)	unitless	treatment
Seagrass_Sediment_Habitat	indicates whether the core the sample came from was collected from a seagrass or sediment habitat	unitless	treatment
Light_Dark_Incubation	indicates whether the core the sample came from was incubated in a clear or a darkened container	unitless	treatment
NO3_NO2	NO3+NO2 value of the water sample	uM	NO3_NO2
NO2	NO2 value of the water sample	uM	NO2
NH4	NH4 value of the water sample	uM	NH4
TDN	Total dissolved nitrogen in the water sample	uM	TDN
SRP	soluble reactive phosphorous in the water sample	micromole per liter (umol/L)	SRP
Dsi	dissolved silica in the water sample	micromole per liter (umol/L)	silica

Status message

Database

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Dataset: Diatom contribution to benthic GPP - Silica and Nitrogen analyses