Identification

Title

Growing degree-day measurement of cyst germination rates in the toxic dinoflagellate Alexandrium catenella

Abstract

Blooms of many dinoflagellates, including several harmful algal bloom (HAB) species, are seeded and revived through the germination of benthic resting cysts. Temperature is a key determinant of cysts' germination rate, and temperature-germination rate relationships are therefore fundamental to understanding species' germling cell production, cyst bed persistence, and resilience to climate warming. This study measured germination by cysts of the HAB dinoflagellate Alexandrium catenella using a growing degree-day (DD) approach that accounts for the time and intensity of warming above a critical temperature. Time courses of germination at different temperatures were fit to lognormal cumulative distribution functions for the estimation of the median days to germination. As temperature increased, germination times decreased hyperbolically. DD scaling collapsed variability in germination times between temperatures after cysts were oxygenated. A parallel experiment demonstrated stable temperature-rate relationships in cysts collected during different phases of seasonal temperature cycles in situ over three years. DD scaling of the results from prior A. catenella germination studies showed consistent differences between populations across a wide range of temperatures and suggests selective pressure for different germination rates. The DD model provides an elegant approach to quantify and compare the temperature dependency of germination among populations, between species, and in response to changing environmental conditions. IMPORTANCE Germination by benthic life history stages is the first step of bloom initiation in many, diverse phytoplankton species. This study outlines a growing degree-day (DD) approach for comparing the temperature dependence of germination rates measured in different populations. Germination by cysts of Alexandrium catenella, a harmful algal bloom dinoflagellate that causes paralytic shellfish poisoning, is shown to require a defined amount of warming, measured in DD after cysts are aerated. Scaling by DD, the time integral of temperature difference from a critical threshold, enabled direct comparison of rates measured at different temperatures and in different studies.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7k0787h

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2022-06-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact