Dataset: Flowering survey Zostera marina density

Name: Vegetative and flowering density of Zostera marina determined from from weekly-biweekly surveys in shallow and deep zones at two sites in Massachusetts, USA in 2019
Published: 2021-03-30
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.847023.1

Spatial Extent: N:42.55921 E:-70.80578 S:42.42009 W:-70.91553

Temporal Extent: 2019-06-04 - 2019-08-27

Project:

RUI: Collaborative Research: Trait differentiation and local adaptation to depth within meadows of the foundation seagrass Zostera marina (ZosMarLA)

Principal Investigator:

A. Randall Hughes (Northeastern University)

BCO-DMO Data Manager:

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

Version:

Version Date:

2021-03-30

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Vegetative and flowering density of Zostera marina determined from from weekly-biweekly surveys in shallow and deep zones at two sites in Massachusetts, USA in 2019

Abstract:

This dataset includes vegetative and flowering density of Zostera marina determined from from weekly-biweekly surveys in shallow and deep zones at two sites in Massachusetts, USA in 2019. Eleven surveys of two different eelgrass beds were conducted every 1-2 weeks starting June 4th and ending August 27th during the summer of 2019. The two sites were West Beach in Beverly (N 42.55921, W 70.80578) and Curlew Beach in Nahant (N 42.42009, W 70.91553).

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2021-03-30	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.847023.1	2021-04-01

Methods & Sampling

We conducted eleven surveys of two different eelgrass beds in Massachusetts every 1-2 weeks starting June 4th and ending August 27th during the summer of 2019. The two sites were West Beach in Beverly (N 42.55921, W 70.80578) and Curlew Beach in Nahant (N 42.42009, W 70.91553). Each survey consisted of a 20 m transect being laid out parallel to shore in both the shallow and deep zone. These zones were defined as being along the respective edges of the eelgrass beds. The exact depths of the zones varied from bed to bed.

During each survey we counted the number of both flowering and vegetative shoots in a 0.25 m^2 quadrat every 2 meters along the transect. If a quadrat had no shoots, an additional quadrat was added at the end of the transect. A few weeks we sampled more than 10 quadrats per depth.

Data Processing Description

Data Processing:
We analyzed the number of vegetative shoots per 0.25 m^2 quadrat using a generalized linear model (GLM) with a negative binomial regression and site, depth, and time (week) as fixed effects and including all possible interactions. We did the same for the density of flowering shoots and the density of all shoots (total density). We analyzed the proportion of flowering shoots (% flowering by density) using a GLM with a quasi binomial distribution and logit link function with site, depth, and time (week) as our fixed effects and including all possible interactions. For all of these analyses, week was treated as a categorical factor.

Statistical analyses were conducted using R Statistical Software v. 3.6.0 (R Core Team 2019). Negative binomial regressions were done using the glm.nb function in the MASS package (Venables and Ripley 2002). We used a significance level of α = 0.05 for all of our analyses.

BCO-DMO Processing:
- changed date format to YYYY-MM-DD;
- renamed fields to conform with BCO-DMO naming conventions;
- replaced "NA" with "nd" to indicate "no data".

Data Files

File
flowering_survey_density.csv (Comma Separated Values (.csv), 19.37 KB) MD5:cd106add96829f7f3b84b85abe89e5ff Primary data file for dataset ID 847023

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1851043

Deployments

None available yet

Instruments

None available yet

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Date	The date of sample collection; format: YYYY-MM-DD Format: %Y-%m-%d	unitless	date
Week	The assigned collection week number. Numbers start at 1 for the first week of collection and go up 1 each collection week.	unitless	time_point
Site	The site of collection. Either West (West Beach, Beverly, MA) or Dorothy (Curlew Beach, Nahant, MA).	unitless	site
Depth	SH (shallow zone) or DP (deep zone).	unitless	site_descrip
Quadrat	For each transect, quadrats will be in order with 1 being the first quadrat of each transect at 2m and 10 being the last at 20m. Some weeks go higher than 10 quadrats if we sampled more or had empty quadrats. Week 4 quadrat numbers do not correspond to transect position/sampling order.	unitless	site
Vegetative_Density	The number of vegetative shoots in each quadrat.	number of shoots per quadrat	density
Flowering_Density	The number of flowering shoots in each quadrat.	number of shoots per quadrat	density
Total_Density	The number of vegetative AND flowering shoots found in each quadrat.	number of shoots per quadrat	density
Pcnt_Flowering_by_Density	(flowering density)/(total density) * 100. The percent of shoots in each quadrat which are flowering.	unitless (percent)	no_bcodmo_term

Database

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Dataset: Flowering survey Zostera marina density