Dataset: Settling response of sand dollar D.excentricus to turbulence (BMC Zoology)
Deployment: Gaylord_Turb-Settlement

Figs 1, 2, 3, BMC Zoology

Principal Investigator:

Dr Matthew Ferner (San Francisco State University, SFSU)

Co-Principal Investigator:

Brian Gaylord (University of California - Davis: Bodega Marine Laboratory, UC Davis-BML)

Dr Jason Hodin (University of Washington Friday Harbor Laboratories, FHL)

Dr Christopher Lowe (Stanford University - Hopkins, Stanford-HMS)

Contact:

Dr Matthew Ferner (San Francisco State University, SFSU)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Project:

Turbulence-spurred settlement: Deciphering a newly recognized class of larval response (Turbulence-spurred settlement)

Data URL:

https://www.bco-dmo.org/dataset-deployment/740424/data

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Description

These data are presented in Hodin et al (2018).

Adult Dendraster excentricus were collected from two geographically distinct populations: 1) a subtidal population (~ 100 m offshore and 1.5m below the surface at mean lower low water) approximately 30m east of Municipal Pier 2 in downtown Monterey CA, USA; 2) an intertidal population on Crescent Beach in East Sound, Orcas Island, WA, USA. Adults in Monterey were collected by snorkeling and transported to Hopkins Marine Station (“HMS”; Pacific Grove CA, USA). Adults in East Sound were collected at low tide and transported to Friday Harbor Labs (“FHL”; Friday Harbor, WA, USA). In both locations, the sand dollars were partially buried within fine sediments (collected from the adult beds) in flowing seawater aquaria until spawning. (Hodin et al, 2018). These adults served as sources for the larvae used in the experiments.

We raised larval sand dollars (Dendraster excentricus) through their feeding larval stage using standard methods [Strathmann, 1987 and 2014], and on various days after larvae had become competent to settle, we subjected a subset of them to a brief turbulence exposure of a specified high intensity (6 W/kg) conforming to that measured on wave-exposed rocky coasts. Immediately after exposure, we transferred the larvae into different settlement inducing media: Millipore-filtered seawater (MFSW), extracts of sand from inside or outside sand dollar beds, or excess potassium chloride in MFSW. We then quantified settlement as it relates to turbulence exposure and settlement medium. For more detail refer to Hodin et al (2018) and prior papers [Gaylord et al, 2013; Hodin et al, 2015].

Methods & Sampling

Dataset acquisition description

Figure 1: Early competent sand dollar larvae do not display 'desperate' behaviors at settlement, with or without turbulence exposure. We either exposed D. excentricus larvae 10 day post fertilization (dpf) (reared at ~20°C) to 3 min of 6 W/kg turbulent shear or did not. Then, we transferred exposed and control larvae into one of two settlement conditions: 24 hrs in MFSW alone (left side of graph) or a 1 hr exposure to 40mM excess KCl in MFSW –to assess competence– followed by a 24 hr recovery in MFSW. We detected an effect both of turbulence exposure (F1,12=5.36, p<0.02) and settlement medium (F1,12=228.93, p<0.001) on proportion of larvae settled, but no clear interaction (F1,12=3.41, p=0.09).

Figure 2: Fully competent sand dollar larvae exposed to turbulence are less choosy about settlement substrate, and thus behave like 'desperate' larvae. We either exposed D. excentricus larvae 11 dpf (reared at ~20°C) to 3 min of 6 W/kg turbulent shear or did not ("no turbulence"). Then, we transferred exposed and control larvae into one of two settlement conditions: 0% extract of sand from sand dollar aquaria (MFSW; no inducer) or 40% extract of sand from sand dollar aquaria (strong natural inducer), and counted the numbers settled at 1 and 16 hrs. We also exposed a separate set of control (no turbulence) larvae for 1 hr to 40mM excess KCl in MFSW, followed by recovery in MFSW. More than 95% of these latter larvae settled, confirming that the larvae in this experiment were indeed fully competent.

Figure 3: Fully competent sand dollar larvae exposed to turbulence are less choosy about settlement substrate, and thus behave like 'desperate' larvae. We either exposed D. excentricus larvae 40 dpf (reared at ~14°C) to 3 min of 6 W/kg turbulent shear or did not ("no turbulence"). Then, we transferred exposed and control larvae into one of two settlement conditions: 0% extract of sand from sand dollar aquaria (MFSW; no inducer) or 200% extract of sand from a beach without sand dollars (poor quality natural inducer), and counted the numbers settled at 1.5, 3, 7.5 and 19 hrs. We also exposed a separate set of control (no turbulence) larvae to a strong natural inducer (30% extract of sand from sand dollar aquaria; right side of graph). This treatment not only confirms that the larvae were fully competent (100% of larvae settled by 8 hrs), but indicates the expected rate of settlement response in a strong cue as a basis of comparison to the sub-optimal cues described above.

We performed all statistical analyses using R (version 3.4.2) and the lme4 package.

Data Processing Description

Dataset Processing Description

BCO-DMO Processing:
- added conventional header with dataset name, PI name, version date, reference information
- renamed parameters to BCO-DMO standard
- replaced blank cells with '-' ('not applicable')

More information about this dataset deployment

Funding

Award Number	Funding Source
OCE-1356966	NSF Division of Ocean Sciences
OCE-1357033	NSF Division of Ocean Sciences
OCE-1357077	NSF Division of Ocean Sciences

Instruments

Taylor-Couette system

Supplied Name:

Supplied Description:

To generate turbulence intensities (quantified in terms of the energy dissipation rate, in units ofWkg−1) ranging from those found in open ocean waters to those arising on wave-battered coasts, we employed a Taylor–Couette cell [29], an apparatus composed of two vertically oriented, coaxial cylinders separated by a 3.5mm gap that contains seawater (described in greater detail in [1]). We held the stationary inner cylinder, and thus the water in the gap, at 19–21◦C by means of a circulating water stream from a temperature-controlled water bath passing through the cylinder’s interior. During operation, the outer cylinder rotated at a prescribed speed causing relative motion between the cylinders and thereby shearing the seawater between them. At rotation speeds employed for testing sand dollar larvae, the
sheared flow was turbulent [1].

[1]Gaylord B, Hodin J, Ferner MC. 2013 Turbulent shear spurs settlement in larval sea urchins. Proc. Natl Acad. Sci. USA 110, 6901–6906. (doi:10.1073/pnas.
1220680110)

Instrument Type

Generic Name: Taylor-Couette system

Generic Description:

An apparatus composed of two vertically oriented, coaxial cylinders separated by a gap that contains seawater. During operation, the outer cylinder rotates at a prescribed speed causing relative motion between the cylinders and thereby shearing the seawater between them.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
figure	figure number from BMC Zoology publication	unitless	no_bcodmo_term
competence	readiness of the larvae to settle	unitless	no_bcodmo_term
date_expt	date of experiment formatted as yyyy-mm-dd	unitless	date
species	species name	unitless	species
rpm	rotations per minute of the Taylor-Couette cell; unmanip = no rotation applied	rotations per minute	no_bcodmo_term
replicate	replicate number	unitless	replicate
dpf	days post fertilization	days	days
cue	settlement inducing media; MFSW = Millipore-filtered seawater; KCl = potassium chloride in seawater	unitless	treatment
number_larvae	number of larvae in experiment	larvae	count
number_settled	number of settled larvae	larvae	count
number_settled_0hr	number of settled larvae at time 0	larvae	count
number_settled_1hr	number of settled larvae at 1 hour	larvae	count
number_settled_16hr	number of settled larvae at 16 hours	larvae	count
number_on_bottom	number of settled larvae	larvae	count
number_settled_1_5hr	number of settled larvae at 1.5 hours	larvae	count
number_settled_8hr	number of settled larvae at 8 hours	larvae	count
number_settled_18hr	number of settled larvae at 18 hours	larvae	count

Database

Contribute Data

Dataset: Settling response of sand dollar D.excentricus to turbulence (BMC Zoology)
Deployment: Gaylord_Turb-Settlement

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: Settling response of sand dollar D.excentricus to turbulence (BMC Zoology)Deployment: Gaylord_Turb-Settlement

Dataset acquisition description

Dataset Processing Description

Dataset: Settling response of sand dollar D.excentricus to turbulence (BMC Zoology)
Deployment: Gaylord_Turb-Settlement