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1. Clam Size Explains Some Variability in Paralytic Shellfish Toxin Concentrations in Butter Clams (Saxidomus gigantea) in Southeast Alaska

   https://doi.org/10.3390/toxins16110464  

   Harley, John R; Blair, Kellie; Cellan, Shannon M; Lanphier, Kari; Pierce, Lindsey; Scott, Cer; Whitehead, Chris; Gribble, Matthew O (November 2024, Toxins)

   Harmful algal blooms (HABs) are a reoccurring threat to subsistence and recreational shellfish harvest in Southeast Alaska. Recent Tribally led monitoring programs have enhanced understanding of the environmental drivers and toxicokinetics of shellfish toxins in the region; however, there is considerable variability in shellfish toxins in some species, which cannot be easily explained by seasonal bloom dynamics. Persistent concentrations of paralytic shellfish toxins (PSTs) in homogenized butter clam samples (n > 6, Saxidomus gigantea) have been observed in several communities, and relatively large spikes in concentrations are sometimes seen without Alexandrium observations or increased toxin concentrations in other species. In order to investigate potential sources of variability in PST concentrations from this subsistence species, we assessed individual concentrations of PSTs across a size gradient of butter clams during a period of relatively stable PST concentrations. We found that increasing concentrations of PSTs were significantly associated with larger clams using a log-linear model. We then simulated six clams randomly sampled from three size distributions, and we determined large clams had an outsized probability of contributing a significant proportion of the total toxicity in a six-clam homogenized sample. While our results were obtained during a period of low HAB activity and cannot be extrapolated to periods of intoxication or rapid detoxification, they have significant ramifications for both monitoring programs as well as subsistence and recreational harvesters. 

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2. Molecular Identification and Toxin Analysis of Alexandrium spp. in the Beibu Gulf: First Report of Toxic A. tamiyavanichii in Chinese Coastal Waters

   https://doi.org/10.3390/toxins13020161  

   Xu, Yixiao; He, Xilin; Li, Huiling; Zhang, Teng; Lei, Fu; Gu, Haifeng; Anderson, Donald M. (February 2021, Toxins)

   null (Ed.)

   The frequency of harmful algal blooms (HABs) has increased in China in recent years. Information about harmful dinoflagellates and paralytic shellfish toxins (PSTs) is still limited in China, especially in the Beibu Gulf, where PSTs in shellfish have exceeded food safety guidelines on multiple occasions. To explore the nature of the threat from PSTs in the region, eight Alexandrium strains were isolated from waters of the Beibu Gulf and examined using phylogenetic analyses of large subunit (LSU) rDNA, small subunit (SSU) rDNA, and internal transcribed spacer (ITS) sequences. Their toxin composition profiles were also determined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). All eight strains clustered in the phylogenetic tree with A. pseudogonyaulax, A. affine, and A. tamiyavanichii from other locations, forming three well-resolved groups. The intraspecific genetic distances of the three Alexandrium species were significantly smaller than interspecific genetic distances for Alexandrium species. Beibu Gulf isolates were therefore classified as A. pseudogonyaulax, A. affine, and A. tamiyavanichii. No PSTs were identified in A. pseudogonyaulax, but low levels of gonyautoxins (GTXs) 1 to 5, and saxitoxin (STX) were detected in A. tamiyavanichii (a total of 4.60 fmol/cell). The extremely low level of toxicity is inconsistent with PST detection above regulatory levels on multiple occasions within the Beibu Gulf, suggesting that higher toxicity strains may occur in those waters, but were unsampled. Other explanations including biotransformation of PSTs in shellfish and the presence of other PST-producing algae are also suggested. Understanding the toxicity and phylogeny of Alexandrium species provides foundational data for the protection of public health in the Beibu Gulf region and the mitigation of HAB events. 

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3. UPDATING THE CLASSIC NEW YORK LAMOKA LAKE AND SCACCIA SITES: REFINED CHRONOLOGIES THROUGH AMS DATING AND BAYESIAN MODELING

   https://doi.org/10.1017/RDC.2023.37  

   Hart, John P; Birch, Jennifer; Manning, Sturt W; Lorentzen, Brita (June 2023, Radiocarbon)

   ABSTRACT The Lamoka Lake and Scaccia sites in present-day New York have played important roles in the development of archaeology in New York, and in the case of Lamoka Lake, in eastern North America. Lamoka Lake is the type site for the “Archaic” period in eastern North American culture history and the “Late Archaic” “Lamoka phase” in New York culture history. The Scaccia site is the largest “Early Woodland” “Meadowood phase” site in New York and has the earliest evidence for pottery and agriculture crop use in the state. Lamoka Lake has been dated to 2500 BC based on a series of solid carbon and gas-proportional counting radiometric dates on bulk wood charcoal obtained in the 1950s and 1960s. Scaccia has been dated to 870 BC based on a single uncalibrated radiometric date obtained on bulk charcoal in the early 1970s. As a result, the ages of these important sites need to be refined. New AMS dates and Bayesian analyses presented here place Lamoka Lake at 2962–2902 BC (68.3% highest posterior density [hpd])) and Scaccia at 1049–838 BC (68.3% hpd). 

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4. Differential Responses of Maximum Versus Median Chlorophyll‐ a to Air Temperature and Nutrient Loads in an Oligotrophic Lake Over 31 Years

   https://doi.org/10.1029/2020WR027296  

   Ward, Nicole K.; Steele, Bethel G.; Weathers, Kathleen C.; Cottingham, Kathryn L.; Ewing, Holly A.; Hanson, Paul C.; Carey, Cayelan C. (June 2020, Water Resources Research)

   Abstract Globally, phytoplankton abundance is increasing in lakes as a result of climate change and land‐use change. The relative importance of climate and land‐use drivers has been examined primarily for mesotrophic and eutrophic lakes. However, oligotrophic lakes show different sensitivity to climate and land‐use drivers than mesotrophic and eutrophic lakes, necessitating further exploration of the relative contribution of the two drivers of change to increased phytoplankton abundance. Here, we investigated how air temperature (a driver related to climate change) and nutrient load (a driver related to land‐use and climate change) interact to alter water quality in oligotrophic Lake Sunapee, New Hampshire, USA. We used long‐term data and the one‐dimensional hydrodynamic General Lake Model (GLM) coupled with Aquatic EcoDyanmics (AED) modules to simulate water quality. Over the 31‐year simulation, summer median chlorophyll‐aconcentration was positively associated with summer air temperature, whereas annual maximum chlorophyll‐aconcentration was positively associated with the previous 3 years of external phosphorus load. Scenario testing demonstrated a 2°C increase in air temperature significantly increased summer median chlorophyll‐aconcentration, but not annual maximum chlorophyll‐aconcentration. For both maximum and median chlorophyll‐aconcentration, doubling external nutrient loads of total nitrogen and total phosphorus at the same time, or doubling phosphorus alone, resulted in a significant increase. This study highlights the importance of aligning lake measurements with the ecosystem metrics of interest, as maximum chlorophyll‐aconcentration may be more uniquely sensitive to nutrient load and that typical summer chlorophyll‐aconcentration may increase due to warming alone. 

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5. From Carnival Games to Plastic Filters: Preparing Elementary Preservice Teachers to Teach Engineering.

   Kidd, J; Pazos, P; Gutierrez, L; Ringleb, S; Rhemer, D; Kaipa, K; Kumi, I; Ayala, O; Cima, F (March 2024, Society for Information Technology and Teacher Education (SITE))

   Preservice teachers (PSTs) in an educational foundations course were tasked with leading elementary students in an engineering design challenge. To explore different approaches for helping the PSTs develop competence in engineering education, two implementation methods were tested. In Spring 2022, PSTs collaborated with undergraduate engineering students to develop carnival-themed design challenge lessons. In Fall 2022, PSTs worked with their PST classmates to teach a professionally prepared engineering lesson focused on designing plastic filters. PSTs’ knowledge of engineering and engineering pedagogy were compared across the two semesters using an exploratory approach. Both groups showed increases in engineering knowledge and engineering pedagogical knowledge. Item-level differences suggest unique benefits to each approach providing insight for teacher educators designing interventions to prepare PSTs to integrate engineering into elementary education. 

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