Seasonal predictability and interannual variability in coastal planktonic communities
type: CreativeWork
description: Understanding the predictability and variability of coastal planktonic communities is essential for forecasting ecosystem responses to environmental change and managing marine resources. This thesis examines seasonal predictability, temperature-phenology relationships, and interannual bloom variability in coastal plankton using two decades of high-resolution observations from the Martha’s Vineyard Coastal Observatory (MVCO). Through automated flow cytometry, we analyzed community dynamics across multiple taxa representing diverse functional groups and seasonal strategies. The first component investigates seasonal predictability patterns across the planktonic community using wavelet analysis, novel cyclicity indices, and lag-adjusted seasonal models. Wavelet analysis reveals that annual periodicity dominates temporal variability, with 71% of taxa exhibiting consistent annual cycles throughout the observation period. However, substantial variation exists in predictability among taxa, with some species serving as reliable seasonal anchors while others display more erratic dynamics. Critically, we demonstrate that shifts in bloom amplitude contribute more to interannual variability than changes in seasonal timing, and that individual taxa often exhibit higher predictability than their aggregated functional groups, challenging common modeling approaches that rely on broad taxonomic categories. The second component examines the mechanistic basis for seasonal predictability by quantifying relationships between temperature timing and bloom phenology. Using year-day crossing models, we assess how temperature threshold transitions predict bloom onset and decline across four representative taxa: Synechococcus (spring), Pseudo-nitzschia (summer), Akashiwo (fall), and Ditylum brightwellii (winter). Results show that bloom onset timing is more tightly coupled to temperature transitions than decline timing, with positive correlations indicating that earlier warming leads to earlie…
abstract: Understanding the predictability and variability of coastal planktonic communities is essential for forecasting ecosystem responses to environmental change and managing marine resources. This thesis examines seasonal predictability, temperature-phenology relationships, and interannual bloom variability in coastal plankton using two decades of high-resolution observations from the Martha’s Vineyard Coastal Observatory (MVCO). Through automated flow cytometry, we analyzed community dynamics across multiple taxa representing diverse functional groups and seasonal strategies. The first component investigates seasonal predictability patterns across the planktonic community using wavelet analysis, novel cyclicity indices, and lag-adjusted seasonal models. Wavelet analysis reveals that annual periodicity dominates temporal variability, with 71% of taxa exhibiting consistent annual cycles throughout the observation period. However, substantial variation exists in predictability among taxa, with some species serving as reliable seasonal anchors while others display more erratic dynamics. Critically, we demonstrate that shifts in bloom amplitude contribute more to interannual variability than changes in seasonal timing, and that individual taxa often exhibit higher predictability than their aggregated functional groups, challenging common modeling approaches that rely on broad taxonomic categories. The second component examines the mechanistic basis for seasonal predictability by quantifying relationships between temperature timing and bloom phenology. Using year-day crossing models, we assess how temperature threshold transitions predict bloom onset and decline across four representative taxa: Synechococcus (spring), Pseudo-nitzschia (summer), Akashiwo (fall), and Ditylum brightwellii (winter). Results show that bloom onset timing is more tightly coupled to temperature transitions than decline timing, with positive correlations indicating that earlier warming leads to earlie…
author: Santos, Miraflor P.
keywords: Plankton, Ecology, Seasonality
date published: 2026-02
date modified: 2026-07-27T22:05:23Z
provider: Woods Hole Oceanographic Institute
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

PropertyValue
property ID: Handle
value: https://hdl.handle.net/1912/72775

PropertyValue
property ID: DOI
value: 10.1575/1912/72775