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1. Long‐term trends in gastropod abundance and biodiversity: Disentangling effects of press versus pulse disturbances

   https://doi.org/10.1111/geb.13425  

   Willig, Michael R.; Presley, Steven J. (November 2021, Global Ecology and Biogeography)

   Abstract AimClimate‐induced pulse (e.g., hurricanes) and press (e.g., global warming) disturbances represent threats to populations, communities, and the ecosystem services that they provide. We leveraged three decades of annual data on tropical gastropods to quantify the effects of major hurricanes, associated secondary succession, and global warming on abundance, biodiversity, and species composition. LocationLuquillo Mountains, Puerto Rico. MethodsGastropod abundance, biodiversity, and composition were estimated annually for each of 27 years in a tropical montane forest that experienced three major hurricanes (Hugo, Georges, and Maria). Generalized linear mixed‐effects, linear mixed‐effects, and linear models evaluated population‐ and community‐level responses to year, ambient temperature, understorey temperature, hurricane, and time since hurricane. Variation partitioning determined the unique and shared variation in biotic responses associated with temperature, disturbance, and succession. ResultsRather than declining, gastropod abundances generally increased through time, whereas the responses of biodiversity were weak and scale dependent. Hurricanes and associated secondary succession, rather than ambient atmospheric temperature, moulded long‐term trends in abundances and biodiversity. Main conclusionsGlobal warming over the past 30 years has not progressed sufficiently to elicit significant responses by gastropods in the Luquillo Mountains. Rather, effects from pulse disturbances (i.e., hurricanes) and secondary succession currently drive long‐term variation in abundance and biodiversity. Gastropods evince high resilience in this tropical ecosystem. Historical exposure to recurrent hurricanes likely imbued the fauna with broad niches that make them resistant to current levels of global warming. We predict that biotic resiliency will be challenged once changes in temperature exceed interannual and inter‐habitat differences that typify this hurricane‐mediated system, or combine with an increased frequency of hurricanes and droughts to alter associations among environmental characteristics that define the fundamental niches of species. Only then might significant declines in abundance or the appearance of novel communities characterize the gastropod fauna in the Luquillo Mountains. 

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2. Shifting phenology as a key driver of shelf zooplankton population variability

   https://doi.org/10.1002/lno.12752  

   Honda, Isabel A; Ji, Rubao; Britten, Gregory L; Thompson, Cameron; Solow, Andrew R; Zang, Zhengchen; Runge, Jeffrey A (January 2025, Limnology and Oceanography)

   Abstract The timing of biological events, known as phenology, plays a key role in shaping ecosystem dynamics, and climate change can significantly alter these timings. The Gulf of Maine on the Northeast U.S. Shelf is vulnerable to warming temperatures and other climate impacts, which could affect the distribution and production of plankton species sensitive to phenological shifts. In this study, we apply a novel data‐driven modeling approach to long‐term datasets to understand the population variability ofCalanus finmarchicus, a lipid‐rich copepod that is fundamental to the Gulf of Maine food web. Our results reveal how phenology impacts the complex intermingling of top‐down and bottom‐up controls. We find that early initiation of the annual phytoplankton bloom prompts an early start to the reproductive season for populations ofC. finmarchicusin the inner Gulf of Maine, resulting in high spring abundance. This spring condition appears to be conducive to enhanced predation pressure later in the season, consequently resulting in overall lowC. finmarchicusabundance in the fall. These biologically controlled dynamics are less pronounced in the outer Gulf of Maine, where water exchanges near the boundary have a greater influence. Our analysis augments existing hypotheses in fisheries oceanography and classical ecological theory by considering unique plankton life‐history characteristics and shelf sea dynamics, offering new insights into the biological factors drivingC. finmarchicusvariability. 

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3. Genomic evidence for global ocean plankton biogeography shaped by large-scale current systems

   https://doi.org/10.7554/eLife.78129  

   Richter, Daniel J; Watteaux, Romain; Vannier, Thomas; Leconte, Jade; Frémont, Paul; Reygondeau, Gabriel; Maillet, Nicolas; Henry, Nicolas; Benoit, Gaëtan; Da Silva, Ophélie; et al (August 2022, eLife)

   Oceans are brimming with life invisible to our eyes, a myriad of species of bacteria, viruses and other microscopic organisms essential for the health of the planet. These ‘marine plankton’ are unable to swim against currents and should therefore be constantly on the move, yet previous studies have suggested that distinct species of plankton may in fact inhabit different oceanic regions. However, proving this theory has been challenging; collecting plankton is logistically difficult, and it is often impossible to distinguish between species simply by examining them under a microscope. However, within the last decade, a research schooner called Tara has travelled the globe to gather thousands of plankton samples. At the same time, advances in genomics have made it possible to identify species based only on fragments of their DNA sequence. To understand the hidden geography of plankton communities in Earth’s oceans, Richter et al. pored over DNA from the Tara Oceans expedition. This revealed that, despite being unable to resist the flow of water, various planktonic species which live close to the surface manage to occupy distinct, stable provinces shaped by currents. Different sizes of plankton are distributed in different sized provinces, with the smallest organisms tending to inhabit the smallest areas. Comparing DNA similarities and speeds of currents at the ocean surface revealed how these might stretch and mix plankton communities. Plankton play a critical role in the health of the ocean and the chemical cycles of planet Earth. These results could allow deeper investigation by marine modellers, ecologists, and evolutionary biologists. Meanwhile, work is already underway to investigate how climate change might impact this hidden geography. 

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4. Resource limitation determines temperature response of unicellular plankton communities

   https://doi.org/10.1002/lno.11140  

   Serra‐Pompei, Camila; Hagstrom, George I.; Visser, André W.; Andersen, Ken H. (February 2019, Limnology and Oceanography)

   Abstract A warmer ocean will change plankton physiological rates, alter plankton community composition, and in turn affect ecosystem functions, such as primary production, recycling, and carbon export. To predict how temperature changes affect plankton community dynamics and function, we developed a mechanistic trait‐based model of unicellular plankton (auto‐hetero‐mixotrophic protists and bacteria). Temperature dependencies are specifically implemented on cellular process rather than at the species level. As the uptake of resources and metabolic processes have different temperature dependencies, changes in the thermal environment will favor organisms with different investments in processes such as photosynthesis and biosynthesis. The precise level of investments, however, is conditional on the limiting process and is ultimately determined dynamically by competition and predation within the emergent community of the water column. We show how an increase in temperature can intensify nutrient limitation by altering organisms' interactions, and reduce relative cell‐size in the community. Further, we anticipate that a combination of temperature and resource limitation reduces ecosystem efficiency at capturing carbon due to strengthening of the microbial loop. By explicitly representing the effects of temperature on traits responsible for growth, we demonstrate how changes on the individual level can be scaled up to trends at the ecosystem level, helping to discern direct from indirect effects of temperature on natural plankton communities. 

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5. An Ecological Succession Lesson from a Beaver’s Point of View

   https://doi.org/10.1525/abt.2022.84.4.229  

   Schmidt, Hannah; Heinrich, Kaleb K.; Reynolds, Jennifer; Howeth, Jennifer G. (April 2022, The American Biology Teacher)

   Ecological succession explored at the secondary and postsecondary level is often limited to terrestrial ecosystems. The emphasis is traditionally placed on how deforestation leads to ecological succession. However, aquatic ecological succession is just as important and allows for many connections to be made with other ecological concepts. Succession initiated by beavers (Castor canadensis) in particular links both aquatic and terrestrial ecosystems over time. We present a guide to an inquiry-based lesson for AP Environmental Science and undergraduate ecology courses that explores the effects of aquatic and terrestrial ecological succession initiated by deforestation and beavers. Specifically, the focus is ecological succession and its effects in both terrestrial and aquatic ecosystems. In this lesson, students (1) engage with a preassessment and broad overview of ecological succession, (2) explore authentic research data representing secondary succession in beaver ponds, (3) explain data using detective activities, (4) elaborate with a mystery pond, and (5) evaluate their new understanding by comparing a pre- and postassessment. This lesson plan meets the objectives for AP Environmental Science Biology courses as well as the core concepts and competencies for undergraduate biology education from the Vision and Change report by the American Association for the Advancement of Science in 2011. 

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