@article {2995,
	title = {ERRONEOUSLY OLD RADIOCARBON AGES FROM TERRESTRIAL POLLEN CONCENTRATES IN YELLOWSTONE LAKE, WYOMING, USA},
	journal = {Radiocarbon},
	volume = {63},
	year = {2021},
	month = {02/2021},
	pages = {321 - 342},
	abstract = {Accelerator mass spectrometry (AMS) dating of pollen concentrates is often used in lake sediment records where large, terrestrial plant remains are unavailable. Ages produced from chemically concentrated pollen as well as manually picked Pinaceae grains in Yellowstone Lake (Wyoming) sediments were consistently 1700{\textendash}4300 cal years older than ages established by terrestrial plant remains, tephrochronology, and the age of the sediment-water interface. Previous studies have successfully utilized the same laboratory space and methods, suggesting the source of old-carbon contamination is specific to these samples. Manually picking pollen grains precludes admixture of non-pollen materials. Furthermore, no clear source of old pollen grains occurs on the deglaciated landscape, making reworking of old pollen grains unlikely. High volumes of CO2 are degassed in the Yellowstone Caldera, potentially introducing old carbon to pollen. While uptake of old CO2 through photosynthesis is minor (F14C approximately 0.99), old-carbon contamination may still take place in the water column or in surficial lake sediments. It remains unclear, however, what mechanism allows for the erroneous ages of highly refractory pollen grains while terrestrial plant remains were unaffected. In the absence of a satisfactory explanation for erroneously old radiocarbon ages from pollen concentrates, we propose steps for further study.},
	keywords = {AMS dating, chronology, contamination, paleoecology, pine},
	isbn = {0033-8222, 1945-5755},
	doi = {10.1017/RDC.2020.118},
	url = {https://www.cambridge.org/core/journals/radiocarbon/article/erroneously-old-radiocarbon-ages-from-terrestrial-pollen-concentrates-in-yellowstone-lake-wyoming-usa/1DAC6B6CCD52443755E7F725B84CFB3F},
	author = {Schiller, Christopher M. and Whitlock, Cathy and Elder, Kathryn L. and Iverson, Nels A. and Abbott, Mark B.}
}
@article {2674,
	title = {{\textquotedblleft}New{\textquotedblright} cyanobacterial blooms are not new: two centuries of lake production are related to ice cover and land use},
	journal = {Ecosphere},
	volume = {11},
	year = {2020},
	month = {Jan-06-2020},
	abstract = {Recent cyanobacterial blooms in otherwise unproductive lakes may be warning signs of impending eutrophication in lakes important for recreation and drinking water, but little is known of their historical precedence or mechanisms of regulation. Here, we examined long-term sedimentary records of both general and taxon-specific trophic proxies from seven lakes of varying productivity in the northeastern United States to investigate their relationship to historical in-lake, watershed, and climatic drivers of trophic status. Analysis of fossil pigments (carotenoids and chlorophylls) revealed variable patterns of past primary production across lakes over two centuries despite broadly similar changes in regional climate and land use. Sediment abundance of the cyanobacteriumGloeotrichia,a large, toxic, nitrogen-fixing taxon common in recent blooms in this region, revealed that this was not a new taxon in the phytoplankton communities but rather had been present for centuries. Histories ofGloeotrichiaabundance differed strikingly across lakes and were not consistently associated with most other sediment proxies of trophic status. Changes in ice cover most often coincided with changes in fossil pigments, and changes in watershed land use were often related to changes inGloeotrichiaabundance, although no single climatic or land-use factor was associated with proxy changes across all seven lakes. The degree to which changes in lake sediment records co-occurred with changes in the timing of ice-out or agricultural land use was negatively correlated with the ratio of watershed area to lake area. Thus, both climate and land management appeared to play key roles in regulation of primary production in these lakes, although the manner in which these factors influenced lakes was mediated by catchment morphometry. Improved understanding of the past interactions between climate change, land use, landscape setting, and water quality underscores the complexity of mechanisms regulating lake and cyanobacterial production and highlights the necessity of considering these interactions-rather than searching for a singular mechanism-when evaluating the causes of ongoing changes in low-nutrient lakes.},
	keywords = {agriculture, basin morphometry, Cyanobacteria, eutrophication, Gloeotrichia, ice-out, land use, Maine, New Hampshire, paleoecology, Sediment chemistry, watershed},
	issn = {2150-8925},
	doi = {10.1002/ecs2.v11.610.1002/ecs2.3170},
	url = {https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.3170},
	author = {Ewing, Holly A. and Weathers, Kathleen C. and Cottingham, Kathryn L. and Leavitt, Peter R. and Greer, Meredith L. and Carey, Cayelan C. and Steele, Bethel G. and Fiorillo, Alyeska U. and Sowles, John P.}
}
@article {2716,
	title = {A 12,700-year history of paleolimnological change from an Andean microrefugium},
	journal = {The Holocene},
	volume = {29},
	year = {2019},
	month = {Jul-02-2020},
	pages = {231 - 243},
	abstract = {We present a 12,6700-yr limnological history of Lake Miski, a high-elevation lake in a wet section of the Peruvian Andes. While many shallow Andean lakes dried up during the mid-Holocene, loss-on-ignition, magnetic susceptibility, and diatom analysis showed that Lake Miski was a constant feature in the landscape. Overall, fluctuations in the fossil diatom communities of Lake Miski tracked changes in insolation, but this was not the only mechanism influencing observed variability. We identify periods when insolation and interactions with the Pacific Ocean may have played a role in structuring local climate and diatom assemblages. The true mid-Holocene Dry Event (MHDE) is manifested in this record between 8000 and 5000 cal BP, but the carbonate stratigraphy and the diatom community indicated that although the level of the lake decreased, it never completely dried out, instead there was higher availability of planktic habitat and stronger mixing than in much of the Holocene. High rates of biological change observed during the late-Holocene in other records from Peru associated with human amplification of climatic signals were not observed in Lake Miski, as this lake may have been too wet and remote to be strongly influenced by human activity. Because of the presence of a woodland microrefugium, Lake Miski was suggested to have been an unusually climatically stable and wet location during the regional drying associated with the MHDE. Our new limnological information provides additional insights relating to this discussion. The presence of the observed woodland apparently withstood fluctuations that induced state changes in the lake and diatom flora, underscoring that microrefugia do not equate to {\textquoteleft}unchanging{\textquoteright} hydrologies or climates.},
	keywords = {Andes, diatoms, drought, enso, Holocene, limnology, microrefugia, mid-Holocene dry event, paleoecology},
	issn = {0959-6836},
	doi = {10.1177/0959683618810400},
	url = {http://journals.sagepub.com/doi/10.1177/0959683618810400},
	author = {de Novaes Nascimento, Majoi and Laurenzi, Anne Gail and Valencia, Bryan G and Van, Robert and Bush, Mark}
}
@article {2791,
	title = {Holocene paleodepositional changes reflected in the sedimentary microbiome of the Black Sea},
	journal = {Geobiology},
	volume = {17},
	year = {2019},
	month = {Sep-07-2020},
	pages = {436 - 448},
	abstract = {Subsurface microbial communities are generally thought to be structured through in situ environmental conditions such as the availability of electron acceptors and donors and porosity, but recent studies suggest that the vertical distribution of a subset of subseafloor microbial taxa, which were present at the time of deposition, were selected by the paleodepositional environment. However, additional highly resolved temporal records of subsurface microbiomes and paired paleoenvironmental reconstructions are needed to justify this claim. Here, we performed a highly resolved shotgun metagenomics survey to study the taxonomic and functional diversity of the subsurface microbiome in Holocene sediments underlying the permanently stratified and anoxic Black Sea. Obligate aerobic bacteria made the largest contribution to the observed shifts in microbial communities associated with known Holocene climate stages and transitions. This suggests that the aerobic fraction of the subseafloor microbiome was seeded from the water column and did not undergo post-depositional selection. In contrast, obligate and facultative anaerobic bacteria showed the most significant response to the establishment of modern-day environmental conditions 5.2 ka ago that led to a major shift in planktonic communities and in the type of sequestered organic matter available for microbial degradation. No significant shift in the subseafloor microbiome was observed as a result of environmental changes that occurred shortly after the marine reconnection, 9 ka ago. This supports the general view that the marine reconnection was a gradual process. We conclude that a high-resolution analysis of downcore changes in the subseafloor microbiome can provide detailed insights into paleoenvironmental conditions and biogeochemical processes that occurred at the time of deposition.},
	keywords = {geomicrobiology, palaeo-environment, paleoecology, sedimentary metagenomes, subsurface microbiome, sulfur cycle.},
	issn = {1472-4677},
	doi = {10.1111/gbi.2019.17.issue-410.1111/gbi.12338},
	url = {https://pubmed.ncbi.nlm.nih.gov/30843322/},
	author = {More, Kuldeep D. and Giosan, Liviu and Grice, Kliti and Coolen, Marco J. L.}
}
@book {2557,
	title = {Coral Reefs of the WorldCoral Reefs of the Eastern Tropical PacificHolocene Reef Development in the Eastern Tropical Pacific},
	volume = {8},
	year = {2016},
	pages = {177 - 201},
	publisher = {Springer Netherlands},
	organization = {Springer Netherlands},
	address = {Dordrecht},
	abstract = {Contrary to early assessments, the eastern tropical Pacific (ETP) is not devoid of well-developed reefs. Significant accumulations of Holocene reef framework are present throughout the region, although they tend to be poorly consolidated, lack the submarine cementation common on most reefs elsewhere in the world, and are subject to considerable bioerosion. These reef frameworks began accreting as early as 7000 years ago. The thickest accumulations of Pocillopora frameworks occur in coastal areas of Mexico, Costa Rica, Panama, and Colombia, but reefs composed of massive corals{\textemdash}species of Porites, Pavona, or Gardineroseris{\textemdash}are present throughout the region. Reef development in the ETP is limited by a variety of characteristics of the physical environment. Because of high turbidity in most areas, reef development is generally restricted to less than ~10 m depth. The spatial extent of reefs in the ETP is also limited from the combined influences of wave action and upwelling. Most reefs in the ETP are only a few hectares in size and the best-developed reefs generally occur in areas sheltered from strong oceanic influence. Upwelling also influences long-term trends in reef development in the region. There does not appear to be a significant impact of upwelling on the millennial-scale growth rates of Panamanian reefs; however, reefs in upwelling environments typically have thinner frameworks than nearby reefs in non-upwelling environments. Furthermore, upwelling may have contributed to a historic shutdown of reef development in Costa Rica and Panama. Although both ecological and oceanographic disturbances have had some impact on the long-term development of reefs in the ETP, the most important control on reef development in this region throughout the Holocene has most likely been the El Ni{\~n}o{\textendash}Southern Oscillation (ENSO). ENSO activity{\textemdash}especially that of the 1982{\textendash}83 and 1997{\textendash}98 El Ni{\~n}o events{\textemdash}has shaped the landscape of coral reefs across the ETP both in recent decades and in the past. Reefs in Pacific Panama and Costa Rica experienced a 2500-year hiatus in vertical growth beginning ~4100 years ago as a result of enhanced ENSO activity. Although the degree of framework accumulation and rate of reef accretion in some parts of the ETP are more similar to that of the western Atlantic than previously thought, the region still remains a marginal environment for reef development. Given the dominant role that climatic variability has played in controlling reef development in the past, the future of reefs in the ETP under accelerating climate change remains uncertain.},
	keywords = {El Ni{\~n}o, Latin American reefs, paleoecology, Reef accretion, Southern Oscillation, Upwelling},
	isbn = {978-94-017-7498-7},
	issn = {2213-719X},
	doi = {10.1007/978-94-017-7499-410.1007/978-94-017-7499-4_6},
	url = {https://link.springer.com/chapter/10.1007\%2F978-94-017-7499-4_6},
	author = {Toth, Lauren T. and Macintyre, Ian G. and Aronson, Richard B.},
	editor = {Glynn, Peter W. and Manzello, Derek P. and Enochs, Ian C.}
}
@article {1828,
	title = {Impact of human activity on regional forest composition and dynamics in central New England},
	journal = {Ecosystems},
	volume = {1},
	year = {1998},
	month = {Jan-Feb},
	pages = {76-95},
	abstract = {Historical and ecological data from north-central Massachusetts suggest that widespread and intensive human disturbance after European settlement led to a shift in forest composition and obscured regional patterns of species abundance. A paleoecological approach was required to place recent forest dynamics in a long-term context. Pollen and charcoal data from 11 small lakes in north-central Massachusetts were used to reconstruct local vegetation dynamics and fire histories across the region over the past 1000 years. The sites are located across an environmental gradient. Paleoecological data indicate that prior to European settlement, there was regional variation in forest composition corresponding to differences in climate, substrate, and fire regime. Oak, chestnut, and hickory were abundant at low elevations, whereas hemlock, beech, sugar maple, and yellow birch were common at high elevations. Fire appears to have been more frequent and/or intense at lower elevations, maintaining high abundances of oak, and archaeological data suggest Native American populations were greater in these areas. A change in forest composition at higher elevations, around 550 years before present, may be related to the Little Ice Age (a period of variable climate), fire, and/or activity by Native Americans, and led to regional convergence in forest composition. After European settlement, forest composition changed markedly in response to human disturbance and there was a sharp increase in rates of vegetation change. Regional patterns were obscured further, leading to homogenization of broad-scale forest composition. There is no indication from the pollen data that forests are returning to pre-European settlement forest composition, and rates of vegetation change remain high, reflecting continuing disturbance on the landscape, despite regional reforestation.},
	keywords = {awenda provincial park, eastern north-america, european settlement, forest dynamics, history, human disturbance, lake sediment, land-use, new england, paleoecology, patterns, rates of change, united-states, vegetation dynamics},
	isbn = {1432-9840},
	author = {Fuller, T. L.  and Foster, D. R.  and McLachlan, T. S.  and Drake, N.}
}
