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1. Residual flow in a deglaciated coastal bay with low freshwater input

   https://doi.org/10.1016/j.csr.2025.105505  

   Bailey, Taylor; Ross, Lauren; Rojas, Cristian (September 2025, Continental Shelf Research)

   The drivers of the tidal and residual flows in estuaries can vary spatially and temporally due to geomorphic complexities, fortnightly tides, and climatic influences. In this paper, we explore the mechanisms that give rise to the circulation patterns in Frenchman Bay, Maine, on the Eastern Coast of the USA, under varying freshwater input conditions and fortnightly tidal phases, using idealized simulations from a high-resolution, three-dimensional numerical model. The results of the simulations at the tidal timescale reveal a tidal asymmetry in vorticity, where vorticity generated during flood tide is not spun-down during the subsequent ebb. This asymmetry prompts the investigation of the residual circulation in the bay which is characterized by large tidal residual eddies. These eddies are found to persist in the depth-averaged residual flow regardless of the freshwater input or tidal phase, leading to the conclusion that the eddies are “geomorphically-constrained” in the bay. Analysis of the horizontal momentum terms and a simulation performed without Coriolis forcing demonstrates that the tidal stress terms predominantly balance the barotropic pressure gradient to give rise to the eddy patterns, while the Coriolis force acts to strengthen their vorticity. The eddies create a laterally sheared residual flow structure with depth, however the flow is more vertically sheared during the neap tide when the baroclinic pressure gradient plays a larger role. These findings demonstrate the persistence of tidal residual eddies regardless of freshwater input or fortnightly tidal phase in a geomorphically complex deglaciated coastal bay with low freshwater input. 

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2. Range expansion of the lady crab Ovalipes ocellatus Herbst, 1799 (Decapoda: Brachyura: Portunidae) due to ocean warming

   https://doi.org/10.1093/jcbiol/ruaf018  

   Johnson, Maclaren_G; Acosta-Rodríguez, Valerie_N; Johnson, David_S (March 2025, Journal of Crustacean Biology)

   Abstract Ocean warming caused by global climate change is driving range expansions and shifts in marine species. The lady crab Ovalipes ocellatus (Herbst, 1799) is generally found south of Cape Cod, Massachusetts, USA with a disjunct population in the southern Gulf of St. Lawrence, Canada, but absent in the Gulf of Maine and Bay of Fundy. Here we present trawl survey data, recent crowd-sourced observations, and temperature data that suggest a range expansion of O. ocellatus north of Cape Cod into the Gulf of Maine and Bay of Fundy after a marine heat wave in 2012. Crowd-sourced observations of lady crabs increased in the Gulf of Maine at the same time that abundances surged after 2000. In the Gulf of Maine, O. ocellatus was found as far north as Freeport, Maine (43°48′17.136″N, 70°6′30.9594″W) and in the Bay of Fundy as far north as Alma, New Brunswick, Canada (45°36′ 13.6794″N, 64°56′29.184″W). We also extend the southern limit of O. ocellatus to St. Augustine, Florida, USA (29°42′9.432″N, 81°13′56.028″ W). The recent observations of O. ocellatus in the northwestern Atlantic and higher abundances combined with continued warming in this area may signal a permanent expansion of this species. If so, a key goal for ecologists and managers will be to understand the effects of O. ocellatus on food webs and fisheries in the Gulf of Maine and Bay of Fundy. 

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3. Bridging the spawner-recruit disconnect II: Revealing basin-scale correlations between zooplankton and lobster settlement dynamics in the Gulf of Maine

   Shank, B; Carloni, J; Geoghegan, P; Fields, D; Goode, A; Walsh, H; Wahle, R (June 2024, Fisheries Research)

   In recent decades, recruitment of young-of-year lobsters to benthic nursery habitats in the Gulf of Maine was regionally synchronized and exhibited correlative links with changes in the abundance of the copepod Calanus finmarchicus, a foundational zooplankton species of the pelagic food web. The spatial scale at which recruitment dynamics were correlated indicated that recruitment processes were not as strongly coupled to trends in spawner abundance as might be expected, but, rather, were influenced by common, ecosystem-scale processes. Here we explored how local- and basin-scale zooplankton dynamics and oceanographic indicators in the Gulf of Maine correlated with lobster settlement indices and each other since the late 1980s. Our analysis indicates that lobster settlement trends in southwestern Gulf of Maine study areas, from Midcoast Maine to Cape Cod Bay, tend to be significantly correlated with basin-wide C. finmarchicus dynamics and the composition of waters entering the Gulf of Maine through the Northeast Channel. In contrast, lobster settlement in the northeastern Gulf, from Penobscot Bay to the Bay of Fundy, tended to correlate more strongly to C. finmarchicus variability in the Bay of Fundy region, which was distinct in earlier years but converged with the broader basin-scale processes in the latter years. Our results are consistent with the hypothesis that the combined effect of climate-related declines in abundance and phenological shifts of C. finmarchicus have contributed to declines in lobster settlement over the past decade, and justify further research into the mechanisms of this interaction. These changes also align with the weakening influence of cold Labrador Slope Water and strengthening effects of warm Gulf Stream waters that precipitated an ecosystem-wide regime shift in the Gulf of Maine over the past decade and may have greater implications for lobster recruitment than previously suspected. 

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4. Setting Up Roots: Opportunities for Biocultural Restoration in Recently Inhabited Settings

   https://doi.org/10.3390/su15032775  

   Hunt, Carter A.; Jones, Melanie E.; Bustamante, Ernesto; Zambrano, Carla; Carrión-Klier, Carolina; Jäger, Heinke (February 2023, Sustainability)

   Biocultural approaches to restoration, which recognize the unique ways of understanding of socioecological challenges by Indigenous and local communities, have gained traction in recent decades. Yet, less attention has focused on biocultural opportunities where there is no Indigenous population or traditional knowledge to draw upon. This ethnographic study inductively assesses data gathered from interviews with farm owners on Isabela Island in the Galápagos Islands, where human presence is a function of recent migration. These interviews, corroborated with archival information and participant observation, center on farmer attitudes regarding restoration of Scalesia cordata, a highly endangered plant species, endemic to Isabela. The resulting analysis identified four themes of overlap with the biocultural restoration literature: cultural keystone species, sense of place, informational pathways, and recognition of socio-ecological feedback loops. Findings indicate that Scalesia remains a valued cultural keystone species providing tangible and intangible benefits to local residents, and its survival serves as a metaphor for farmers’ own wellbeing. Thus, even locations where place-based knowledge by a native population is not evident, critical biocultural elements exist that can be integrated into restoration efforts. Farmers also exhibited clear connections between restoration and tourism in Galápagos, paving the way for the application of biocultural theory to the analysis of tourism-supported restoration efforts elsewhere. 

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5. Geomorphological controls on estuary hydrodynamics with implications for diatom blooms in deglaciated coastal areas

   https://doi.org/10.1016/j.scitotenv.2024.174902  

   Bailey, Taylor; Ross, Lauren; Tiner, Nicholas; Smith, Sean MC; Pérez_Santos, Iván Ernesto; Ramos, Antonio; García_Mendoza, Alejandro; Miller, David (October 2024, Science of The Total Environment)

   Understanding local hydraulic conditions is imperative to coastal harmful algal bloom (HAB) monitoring. The research summarized herein describes how the locations and tidal phases selected for coastal hazard sampling can influence measurement results used to guide management decisions for HABs. Our study was conducted in Frenchman Bay, Maine, known for its complex deglaciated coastline, strong tidal influence, and shellfishing activities that are susceptible to problematic HABs such as those produced by some species (spp.) of the diatom genus Pseudo-nitzschia. In-situ measurements of current velocity, density, and turbulence collected over a semidiurnal tidal cycle and a companion numerical model simulation of the study area provide concurrent evidence of two adjacent counter-rotating sub-mesoscale eddies (2–4 km diameter) that persist in the depth-averaged residual circulation. The eddies are generated in the wake of several islands in an area with abrupt bathymetric gradients, both legacy conditions partly derived from deglaciation ∼15 kya. Increased concentrations of Pseudo-nitzschia spp. measured during the semidiurnal survey follow a trend of elevated turbulent dissipation rates near the water surface, indicating that surface sampling alone might not adequately indicate species abundance. Additional measurements of Pseudo-nitzschia spp. from two years of weekly sampling in the region show that algal cell abundance is highest where residual eddies form. These findings provide incentive to examine current practices of HAB monitoring and management by linking coastal geomorphology to hydraulic conditions influencing HAB sampling outcomes, coastal morphometric features to material accumulation hotspots, and millennial time scales to modern hydraulic conditions. 

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