Dataset: Feeding Trials
Deployment: BML_Stachowicz

Feeding trials using detritus from eelgrass (Zostera marina) genotypes (clones) as a food source and either one or a combination of invertebrate grazers

Principal Investigator:

John J. Stachowicz (University of California-Davis, UC Davis)

Co-Principal Investigator:

Richard K. Grosberg (University of California-Davis, UC Davis)

Susan L. Williams (University of California-Davis, UC Davis-BML)

Contact:

Laura K. Reynolds (University of Florida, UF)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Connecting genetic diversity to ecosystem functioning: links between genetic diversity, relatedness and trait variation in a seagrass community (Genetic Div to Ecosys Functioning)

Current State:

Final no updates expected

Version:

15 September 2017

Version Date:

2017-09-15

Data URL:

https://osprey.bco-dmo.org/dataset-deployment/715134/data

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Description

In this project, we examined the effect of eelgrass genetic and invertebrate species diversity on detrital consumption and animal survival rates in a series of laboratory experiments. This dataset contains chemical traits for individual eelgrass clones and feeding rates for each grazer type (isopods, amphipods, polychaetes).

Abstract:
Seagrass meadows are among the world's most productive ecosystems, and as in many other systems, genetic diversity is correlated with increased production. However, only a small fraction of seagrass production is directly consumed, and instead much of the secondary production is fueled by the detrital food web. Here, we study how plant genotype influences detrital consumption. We used three common mesograzers—an amphipod, Ampithoe lacertosa, an isopod, Idotea resecata, and a polychaete, Platynereis bicanaliculata. Each grazer consumed eelgrass detritus at rates greater than live eelgrass or macroalgae. This detrital consumption, however, was not spread evenly over leaves shed from different eelgrass clones. Palatability and consumption varied because of genotype specific differences in leaf texture, secondary metabolites (phenolics), and nutritional quality (nitrogen). Further, detritus derived from some eelgrass genotypes was palatable to all grazers, while detritus from other genotypes was preferentially consumed by only one grazer species.

These data are illustrated in figures 2 and 3 of the manuscript:
Reynolds LK, KM Chan, E Huynh, SL Williams, and JJ Stachowicz (in press) Plant genotype indentity and diversity interact with mesograzer species diversity to influence detrital consumption in eelgrass meadows. DOI:10.1111/oik.04471

Methods & Sampling

Dataset acquisition description

We conducted a series of food choice experiments using detritus from cultured eelgrass (Zostera marina) genotypes (clones) as a food source and either one or a combination of the following invertebrate grazers: the tube dwelling amphipod Ampithoe lacertosa, the free swimming isopod Idotea resecata, and/or the tube building polychaete Platynereis bicanaliculata.

All feeding trials were conducted by placing pre-weighed fragments of each choice (approximately 4 cm in length) in 140 mL cups (7 cm tall, 6 cm diameter) covered with a 250 um mesh cloth and submerged in a flowing seawater bath in an indoor tank. Food choices were marked using colored zip ties, and trials were terminated before any food item was reduced in size by one half. Consumption was calculated as ([Hi X Cf/Ci] - Hf ), where Hi and Hf were initial and final wet masses of tissue exposed to consumers, and Ci and Cf were initial and final masses in controls.

In addition to feeding trials, we grew invertebrates for one month (in similar containers and feeding trial conditions) with food sources that varied in number of seagrass clones present. Animal survival was assessed weekly, and food was replaced.

The chemical traits for individual eelgrass clones were also assessed. We measured the pressure required to penetrate and tear each genotype. We clamped in place below a needle (17G / 19mm length), which was held in place with a metal sleeve and which supported a cup to which dry sand was added a few milligrams at a time until the pin pierced completely through the plant tissue. The mass of the dry sand and the apparatus were then weighed to determine the mass needed to pierce the leaf (Duffy & Hay 1991). Tensile strength was measured using a tensiometer. Leaf segments were clamped to a hanging balance equipped with a maximum mass indicator and pulled by hand until the leaf failed. Phenolic content was determined on an approximately 4 mg subsample using a modified Folin-Ciocalteu method (see Bolser et al. 1998). An approximately 3 mg subsample was analyzed for carbon and nitrogen concentration on a Thermo Flash EA 1112 Soil elemental analyzer.

Data Processing Description

Dataset Processing Description

BCO-DMO Processing:
- separated original Excel file into 3 datasets: feeding trials, biodiversity experiments, invertebrate survival;
- modified parameter names to conform with BCO-DMO naming conventions: replaced % with pcnt, replaced spaces with underscores.

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1234345	NSF Division of Ocean Sciences

Instruments

Aquarium

Supplied Name: indoor tank

Supplied Description:

Pre-weighed fragments of eelgrass were covered with a 250 um mesh cloth and submerged in a flowing seawater bath in an indoor tank.

Instrument Type

Generic Name: Aquarium

Generic Description:

Aquarium - a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept

Elemental Analyzer

Supplied Name: Thermo Flash EA 1112 Soil elemental analyzer

Supplied Description:

Carbon and nitrogen concentrations were measured on a Thermo Flash EA 1112 Soil elemental analyzer.

Instrument Type

Generic Name: Elemental Analyzer

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB01/

Generic Description:

Instruments that quantify carbon, nitrogen and sometimes other elements by combusting the sample at very high temperature and assaying the resulting gaseous oxides. Usually used for samples including organic material.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
Genotype	Individual clone	unitless	sample_descrip
Nitrogen_pcnt	Detrital leaf nitrogen content	percent (%)	N
Carbon_pcnt	Detrital leaf carbon content	percent (%)	C
Tear_g	The mass recordered by a tensiometer reqired to break a detrial leaf	grams (g)	mass
Penetrate_g	The mass needed to push a needle through a detrial leaf	grams (g)	mass
Phenolic_pcnt	Phenolic concentration measured by the Folin Ciocalteu method	percent (%)	no_bcodmo_term
Isopod_feeding_rate_mg_day	Isopod (Idotea rescata) feeding rate	milligrams per day (mg/day)	no_bcodmo_term
Amphipod_feeding_rate_mg_day	Amphipod (Amphithoe lacertosa) feeding rate	milligrams per day (mg/day)	no_bcodmo_term
Polychaete_feeding_rate_mg_day	Polychaete (Platynereis bicanicalulata) feeding rate	milligrams per day (mg/day)	no_bcodmo_term

Database

Contribute Data

Dataset: Feeding Trials
Deployment: BML_Stachowicz

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Feeding TrialsDeployment: BML_Stachowicz

Dataset acquisition description

Dataset Processing Description

Dataset: Feeding Trials
Deployment: BML_Stachowicz