Experimental results on sand dollar larvae settlement following turbulence exposure from Bodega Marine Lab in 2014 (Turbulence-spurred settlement project)

Website: https://www.bco-dmo.org/dataset/640481
Data Type: experimental
Version: 2016-03-14

Project
» Turbulence-spurred settlement: Deciphering a newly recognized class of larval response (Turbulence-spurred settlement)
ContributorsAffiliationRole
Gaylord, BrianUniversity of California-Davis (UC Davis-BML)Principal Investigator
Ferner, MatthewSan Francisco State University (SFSU)Co-Principal Investigator, Contact
Lowe, ChristopherStanford University - Hopkins (Stanford-HMS)Co-Principal Investigator
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager


Dataset Description

Figure 7. Precompetent sand dollar larvae will settle following turbulence exposure in the presence of a natural inducer. (a) Twice as many larvae settled in sand extract following a 3 min exposure to intense turbulence (approx. 6 W kg−1; unpaired t-test, t4=−3.72, p=0.02). (b) Settlement in 40 mM excess KCl with this same batch of larvae also showed approximately 20% settlement following the same level of turbulence exposure, and was elevated relative to a no-turbulence, unmanipulated control treatment (Kruskal–Wallis, H2=−9.39, p<0.01), as well as an accompanying handling control (not shown). Note that we conducted this experiment on day 12 from our 25 August 2014 fertilization, a batch of larvae that was delayed relative to our other batches due, we suspect, to colder room temperatures and slightly more crowded conditions. These day 12 larvae were approximately the same stage (using our staging scheme modified from [20]) as the day 9–10 larvae from our other fertilizations (data not shown). Error bars are s.e.m.

See Hodin et al (2015) for full details.

Related Reference:
Hodin J, Ferner MC, Ng G, Lowe CJ, Gaylord B. 2015. Rethinking competence in marine life cycles: ontogenetic changes in the settlement response of sand dollar larvae exposed to turbulence. Royal Society Open Science. 2: 150114. doi: 10.1098/rsos.150114.

Related Datasets:
Turbulence settlement: fig.3
Turbulence settlement: fig.4-6_Batches A & B
Turbulence settlement: fig.4-6_Batch C
Turbulence settlement: fig.6b
Turbulence settlement: fig.8
Turbulence settlement: fig.8 bootstrap


Data 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 in replicate column and hypens in other columns with NA ('not applicable')


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Data Files

File
fig7.csv
(Comma Separated Values (.csv), 703 bytes)
MD5:9d291b556e603425050359d7f34400b7
Primary data file for dataset ID 640481

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Parameters

ParameterDescriptionUnits
spin_time_sectime the larvae were subjected to turbulence in the Taylor–Couette cell seconds
replicatereplicate number unitless
cuetype of settlement cue: KCl= chemical settlement inducer (potassium chloride); NI = natural inducer (sand) unitless
num_in_couettenumber of larvae in Taylor–Couette cell larvae
time_out_of_couettetime larvae were removed from Taylor–Couette cell HHMM
time_in_cuetime larvae were placed in well with settlement cue HHMM
target_score_timetarget time for larvae to be scored HHMM
time_scoredactual time larvae were scored HHMM
hrs_in_cuetime the larvae were left in settlement wells with cue material hours
num_transferrednumber of larvae transferred to wells larvae
num_juvsnumber to larvae that metamorphosed to juveniles larvae
num_recovered_in_wellthe number of larvae successfully retrieved from the couette device after each treatment larvae
num_settlednumber of larvae that settled larvae
proprtn_settledproportion of larvae that settled unitless
commentcomment unitless


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Instruments

Dataset-specific Instrument Name
Generic Instrument Name
Taylor–Couette system
Dataset-specific Description
To generate turbulence intensities (quantified in terms of the energy dissipation rate, in units of Wkg−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)
Generic Instrument 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.


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Deployments

Gaylord_Turb-Settlement

Website
Platform
lab Bodega Marine Laboratory
Start Date
2014-06-01
End Date
2014-08-31
Description
sand dollar settlement studies


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Project Information

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

Coverage: Northeast Pacific


Description from NSF award abstract:
With this award the investigators will explore a habitat-scale oceanographic process that has the potential to integrate studies of larval delivery with an understanding of how larvae respond to substrate-associated cues. This work will build on published and preliminary data indicating that turbulent shear characteristic of high-energy near shore environments primes larvae to initiate settlement and to transform into the juvenile stage. These prior findings suggest that: 1) Because turbulence intensity varies predictably as a function of the strength of wave breaking and other factors, turbulence could operate as an indicator for larvae of their approach to suitable habitat, providing a link between larger-scale dispersal phenomena, and near-bottom search and selection behaviors; and 2) The larval response to turbulence acts in an unprecedented fashion. In contrast to typical cues, turbulence does not induce settlement directly, but rather spurs otherwise "pre-competent" larvae that are refractory to chemical cues to become "competent", thereby causing them to acquire responsiveness to such cues and undergo settlement. The interdisciplinary team has combined expertise in larval biology, sensory ecology, and organism-flow interactions necessary to address this topic. They will employ a phylogenetically robust approach to explore the scope and adaptive significance of the turbulence response in a widespread and ecologically important class of organisms (echinoids; sea urchins and their relatives), and will determine whether the response is aligned with environmental conditions characteristic of these organisms' adult habitat. They will also test for ecologically important functional consequences of precocious, turbulence-induced settlement. This work will provide a detailed look at an entirely new class of settlement inducer, one with strong potential for changing current conceptualizations of dispersing larval stages, their ability to detect signatures of habitat across multiple scales, and the ways in which organism-level traits might influence population connectivity.

How organisms with dispersing life stages find their way back to adult habitat is a fundamental question in marine ecology. Considerable research has explored links between transport, delivery, settlement, and recruitment, with important advances in knowledge. However, a complete understanding of the larval recruitment process remains elusive. Standard tools for estimating dispersal (e.g., numerical circulation models) have limited spatial resolution, which prevents them from predicting at scales below a few hundred meters how larvae will interact with the shore. Studies investigating larval attachment have focused on chemical, tactile, or near-bottom hydrodynamic cues active across microns to centimeters. The novelty of the present project is that it will focus on processes at habitat scales -- between transport and settlement -- where there is a gap in the understanding of processes.

This project will provide a framework for integrating key concepts of propagule dispersal and settlement, two fundamental but largely disjunct themes in marine science. The understanding that will come from this study will provide key information for ecosystem based management of coastal marine resources. The investigators will develop a "Surfing to Settlement" virtual lab activity based on their research that will be incorporated into the VirtualUrchin web platform, a widely exploited educational resource at Stanford that gets thousands of unique users per month. Through connections to the San Francisco Bay National Estuarine Research Reserve, they will integrate the "Surfing to Settlement" activity into one of NERRs professional development workshops for central California educators, thus disseminating this resource to and gaining valuable feedback from dozens of teachers and thousands of students.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)
NSF Division of Ocean Sciences (NSF OCE)
NSF Division of Ocean Sciences (NSF OCE)

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