What did you say about my mother? The complexities of maternally derived chemical signatures in otoliths

Fisher

Vervoort

2020

Preprint

Self Cite

Chronological data from hard structures has been instrumental in reconstructing information about the past across numerous disciplines. Isotopic and trace elemental chronologies from the depositional layers of speleothems, corals, bivalve shells, fish otoliths and other structures are routinely used to reconstruct climate, growth, temperature, geological, archeological and migratory histories. Advances in instrumentation have revolutionized the use of these structures and publications detailing new chemical and isotopic methods in sclerochronology and speleothem chronology have steadily increased in number. This is particularly true of fish, in which detailed origin, life-history, and migration history can be reconstructed from their otoliths. Specifically, improvements in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have allowed increases temporal resolution, precision, and sample throughput. Many studies now combine multiple chemical and isotopic tracers, taking advantage of multivariate statistical methods and multiple tracep-element and isotope systems to glean further information from individual samples. This paper describes a novel laser ablation split-stream (LASS) method which allows simultaneous collection of 87 Sr/ 86 Sr and traceelemental data from chronological carbonate samples. The study tests the accuracy and precision of multiple laser spot sizes on a marine shell standard and fish otoliths using LASS and traditional single stream methods and compared to prior otolith data on the same samples. Our results indicate that LASS techniques can be used to provide accurate and precise data at useful laser spot sizes for otolith studies, while providing time and integration-matched data reduction using newly developed features for the Iolite data reduction platform.

Section: Experimental Designmentioning

confidence: 99%

Section: Instrument Settingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Simultaneous determination of⁸⁷Sr/⁸⁶Sr and trace-element data in otoliths and other sclerochronological hard structures

Fisher

Vervoort

2020

Preprint

Self Cite

Sawfish, read in tooth and saw: Rostral teeth as endogenous chemical records of movement and life‐history in a critically endangered species

Graves

Fisher

2021

Aquatic Conservation

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The ecology of endangered and rare species can be difficult to study owing to their low abundances and legal limits on scientist’s ability to catch, sample, and track them. This is particularly true of sawfish (family Pristidae), whose numbers have declined precipitously, placing all five species on the IUCN Red List of Threatened Species worldwide. Best known for their distinctive, toothed rostrum, the ecology, movement and life‐history of sawfish are poorly understood. Sawfish rostral teeth are modified placoid scales, which grow continuously throughout the life of the fish. This continuous growth, combined with their stable calcified makeup, makes sawfish rostral teeth a potential source of temporal records of chemical and isotopic changes through the life of the fish. Rostral teeth are often preserved in museums and as curios, potentially providing a source of life‐history data to inform conservation actions without the need for field study, or as an important compliment to it. This is the first study to recover temporally explicit chemical data from sawfish rostral teeth. Using archived samples of largetooth sawfish (Pristis pristis) we show that multiple chemical tracers can be recovered from sawfish rostral teeth, and that these tracers can be used to understand movement across salinity gradients. We further show that sawfish rostral teeth contain repeated structures and indistinct banding which could potentially be used for ageing or growth analysis of fish.

Let's do the time warp again: non‐linear time series matching as a tool for sequentially structured data in ecology

Kennedy

2021

Ecosphere

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Ecological patterns are often fundamentally chronological. However, generalization of data is necessarily accompanied by a loss of detail or resolution. Temporal data in particular contain information not only in data values but in the temporal structure, which is lost when these values are aggregated to provide point estimates. Dynamic time warping (DTW) is a time series comparison method that is capable of efficiently comparing series despite temporal offsets that confound other methods. The DTW method is both efficient and remarkably flexible, capable of efficiently matching not only time series but also any sequentially structured data set, which has made it a popular technique in machine learning, artificial intelligence, and big data analytical tasks. DTW is rarely used in ecology despite the ubiquity of temporally structured data. As technological advances have increased the richness of small-scale ecological data, DTW may be an attractive analysis technique because it is able to utilize the additional information contained in the temporal structure of many ecological data sets. In this study, we use an example data set of highresolution fish movement records obtained from otolith microchemistry to compare traditional analysis techniques with DTW clustering. Our results suggest that DTW is capable of detecting subtle behavioral patterns within otolith data sets which traditional data aggregation techniques cannot. These results provide evidence that the DTW method may be useful across many of the temporal data types commonly collected in ecology, as well other sequentially ordered "pseudo time series" data such as classification of species by shape.