Patterson Lab Publications 2011-2013

PPatterson, R.T., Lamoureux, E.D.R., Neville, L.A., Macumber, A.L. 2013. Arcellaceans (testate lobose amoebae) as pH indicators in a pyrite mine acidified lake, northeastern Ontario, Canada. Microbial Ecology. 65 (3): 541-554. https://doi.org/10.1007/s00248-012-0108-9

Arcellacea (testate lobose amoebae) were examined in 24 sediment-water interface samples collected over two late August field seasons in 2010 and 2011, from James and Granite lakes, Temagami region, northeastern Ontario. The work was carried out to quantitatively test species-environment relationships in a lake system known to be characterized by a significant pH gradient, partially the result of contamination from the early 20th century Northland Pyrite Mine Co., located on the shoreline in the southern basin of James Lake. Redundancy Analysis (RDA) confirmed that arcellacean assemblage structure was most strongly controlled by pH, explaining 14.06% (p<0.002) of the total variance. Q- and R-mode cluster analysis supported by Detrended Correspondence Analysis (DCA) yielded two major fauna assemblages. The Oligotrophic Assemblage (1) had a Shannon Diversity Index (SDI) ranging up to 2.45, typical of healthy boreal lakes. This assemblage characterized samples collected from higher pH stations within James and Granite lakes away from the immediate area of the mine site, while the Low pH Assemblage-2010 (2a) and Low pH Assemblage-2011 (2b) groupings were from the very low pH environments of James Lake adjacent to the former mine site. Both low diversity assemblages (SDI ranging from 0.62-1.22) were characterized by Arcella vulgaris, a species known to thrive in hostile lacustrine environments. Differing depositional conditions during August 2010, a probable result of different prevailing wind patterns that summer, led to allochthonous specimens of the seasonally planktic Cucurbitella tricuspis dominating the Low pH Assemblage-2010 (2a) fauna.

Watchorn, M.A., Hamilton, P.B., Patterson, R.T. 2013. The paleolimnology of Haynes Lake, Oak Ridges Moraine, Ontario, Canada: documenting anthropogenic and climatic disturbances. Environmental Earth Sciences. 68 (7): 1823-1834. https://doi.org/10.1007/s12665-012-1870-1

Haynes Lake is a small kettle lake located on the Oak Ridges Moraine (ORM), and is within the Greater metropolitan area of Toronto, Ontario; Canada’s most populous region. Lake sedimentation, flux rates, diatoms and thecamoebians extracted from a benthic core were used as biological proxies to evaluate changes in water quality through time as a function of anthropogenic activity and changing climate. High-resolution details of the sedimentary history of the lake were determined through x-ray analysis of the sediment cores. There were two clear periods of disturbance to the Haynes Lake ecosystem from ca 8500 YBP through to ca A.D. 2003 which were significant enough to cause changes in lake sedimentation, the diatom flora, and thecamoebian fauna. The first disturbance was concomitant with the decline in global temperatures following the Hypsithermal Climate Optimum (ca. 4700 YBP). However, the most significant disruption to Haynes Lake over the last 8500 years was the settlement of Europeans and subsequent urban development (ca. A.D. 1875), including the construction of a road immediately adjacent to the lake. Anthropogenic disturbance of inorganic clays in the recent paleosediment record (<5cm) is indicative of more recent eutrophication events.

Babalola et al. 2013. Foraminiferal evidence of a late Holocene westward shift of the Aleutian Low. Journal of Foraminiferal Research. 43 (2):127-142. https://doi.org/10.2113/gsjfr.43.2.127

The late Holocene distribution of agglutinated foraminifera and freshwater thecamoebians were documented within a 12.26 m piston core (VEC02A04) deposited between ~4560 – ~1090 calendar years before present (cal yr BP), collected from glacier-carved Frederick  Sound, Seymour-Belize Inlet Complex, British Columbia. The sedimentary record archived in this core was characterized by unevenly distributed massive and laminated intervals interrupted by occasional slumps and turbidites. The faunal assemblages within the core was characterized by low diversity-low abundance agglutinated foraminiferal faunas (Shannon Diversity Index (SDI ≤1.36) ) with occasional allochthonous freshwater thecamoebians. The predominance of low-oxygen tolerant agglutinated foraminiferal taxa and absence of calcareous fauna indicate that oxygen was the main environmental stressor.  Abundant organic matter in the core sediments provides additional evidence of low oxygen conditions that excluded most organisms that might have utilized this rich food resource.

A moderate upcore increase in the abundance of glaciomarine indicator species (e.g. Spiroplectammina biformis, Recurvoides turbinatus, Portatrochammina bipolaris and Cribrostomoides jeffreysii after 3125cal yr BP (above 7.19 m) indicates a subtle shift to progressively cooler bottom water conditions. The presence of varying proportions of thecamoebians through this upper core interval was likely related to increased spring snowmelt or early summer precipitation, which would have resulted in increased terrestrial erosion (e.g. reworking of marsh sediments into the fjord).  Development of relatively cooler/drier climate conditions in the SBIC during the late Holocene corresponds to the Neoglacial advances in the NE Pacific, which is directly linked to a weakened and/or westward shift in Center of Action of the Aleutian Low.

Roe, H.M., Christine T. Doherty, C.T., Patterson, R.T., Glenn A. Milne, G.A., 2013. Isolation basin records of late Quaternary sea-level change, central mainland British Columbia, Canada. Quaternary International. 310:181-198. https://doi.org/10.1016/j.quaint.2013.01.026

Isolation basin records from the Seymour–Belize Inlet Complex, a remote area of central mainland British Columbia, Canada are used to constrain post-glacial sea-level changes and provide a preliminary basis for testing geophysical model predictions of relative sea-level (RSL) change.  Sedimentological and diatom data from three low-lying (<4 m elevation) basins record falling RSLs in late-glacial times and isolation from the sea by ~11,800-11,200 14C yr BP.  A subsequent RSL rise during the early Holocene (~8,000 14C yr BP) breached the 2.13 m sill of the lowest basin (Woods Lake), but the two more elevated basins (sill elevations of ~3.6 m) remained isolated.  At ~2,400 14C yr BP, RSL stood at 1.49 ± 0.34 m above present MTL.  Falling RSLs in the late Holocene led to the final emergence of the Woods Lake basin by 1,604 ± 36 14C yr BP.  Model predictions generated using the ICE-5G model partnered with a small number of different Earth viscosity models generally show poor agreement with the observational data, indicating that the ice model and/or Earth models considered can be improved upon.  The best data-model fits were achieved with relatively low values of upper mantle viscosity (5×1019  Pa s), which is consistent with previous modelling results from the region.  The RSL data align more closely with observational records from the southeast of the region (eastern Vancouver Island, central Strait of Georgia), than the immediate north (Bella Bella–Bella Coola and Prince Rupert-Kitimat) and areas to the north-west (Queen Charlotte Sound, Hecate Strait), underlining the complexity of the regional response to glacio-isostatic recovery.

Patterson, R.T., Chang, A.S., Prokoph, A., Roe, H.M., Swindles, G.T., 2013. Influence of the Pacific Decadal Oscillation, El Niño-Southern Oscillation and solar forcing on climate and primary productivity changes in the northeast Pacific. Quaternary International. 310: 124-139. https://doi.org/10.1016/j.quaint.2013.02.001

Evidence of 11-year Schwabe solar sunspot cycles, El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) were detected in an annual record of diatomaceous laminated sediments from anoxic Effingham Inlet, Vancouver Island, British Columbia. Radiometric dating and counting of annual varves dates the sediments from AD 1947–1993. Intact sediment slabs were X-rayed for sediment structure (lamina thickness and composition based on gray scale), and subsamples were examined for diatom abundances and for grain size. Wavelet analysis reveals the presence of ~2-3, ~4.5, ~7 and ~9-12-year cycles in the diatom record and an ~11-13 year record in the sedimentary varve thickness record. These cycle lengths suggest that both ENSO and the sunspot cycle had an influence on primary productivity and sedimentation patterns. Sediment grain size could not be correlated to the sunspot cycle although a peak in the grain size data centered around the mid-1970s may be related to the 1976-1977 Pacific climate shift, which occurred when the PDO index shifted from negative (cool conditions) to positive (warm conditions). Additional evidence of the PDO regime shift is found in wavelet and cross wavelet results for S. costatum, a weakly silicified variant of S. costatum, annual precipitation and April to June precipitation. Higher spring (April/May) values of the North Pacific High pressure index during sunspot minima suggest that during this time, increased cloud cover and concomitant suppression of the Aleutian Low (AL) pressure system led to strengthened coastal upwelling and enhanced diatom production earlier in the year. These results suggest that the 11-year solar cycle, amplified by cloud cover and upwelling changes, as well as ENSO, exert significant influence on marine primary productivity in the northeast Pacific. The expression of these cyclic phenomena in the sedimentary record were in turn modulated by the phase of PDO, as indicated by the change in period of ENSO and suppression of the solar signal in the record after the 1976-1977 regime shift.

El Bilali, H., Patterson, R.T., Prokoph, A., 2013. A Holocene paleoclimate reconstruction for eastern Canada base on D18O cellulose of Sphagnum mosses from Mer Bleue Bog. The Holocene. 23 (9): 1260-1271. https://doi.org/10.1177/0959683613484617

This study provides a new understanding of cellulose oxygen (δ18O_cel) isotopic variability in various plant macrofossils, particularly Sphagnum, derived from an ∼9200year succession of Holocene peat in Mer Bleue Bog, Ottawa, Ontario, Canada. The variation of δ18O_cel isotopic composition, commonly used as a proxy of paleotemperature and paleoprecipitation, was compared between (1) Sphagnum and other plant macrofossils down core and (2) Sphagnum species within and between samples. The most common Sphagnum species encountered was Sphagnum magellanicum von Bridel, 1798 with lesser amounts of Sphagnum capillifolium (Breutel) Steudel, 1824, Sphagnum fuscum Klinggräff, 1872 and Sphagnum angustifolium Jensen, 1896. There is a statistically significant offset in δ18O_cel isotopic values (mean offset: 1.6‰, standard deviation=3.2‰, n=19) obtained from Sphagnum in comparison with values obtained from other plant macrofossils, particularly rhizomes. The δ18O_cel isotopic offset (mean offset: 0.1‰, standard deviation=1.0‰, n=11) between Sphagnum specimens from the same core horizons, irrespective of the species analyzed, was statistically insignificant at >95%. These results indicate that δ18O_cel isotopic analysis of bulk peat material with high percentage of rhizome and other vascular plants could result in erroneous paleoclimate reconstructions.

Galloway et al. 2013. Climate change and decadal to centennial-scale climate periodicities recorded in a late Holocene NE Pacific marine record: Examining the role of solar forcing. Palaeogeography, Paleoclimatology, Palaeoecology. 386:669-689. https://doi.org/10.1016/j.palaeo.2013.06.031

We report on recent geoscience data collected by the Geological Survey of Canada in collaboration with Northwest Territories Geoscience Office and Carleton University. Fifty sediment-water interface samples from 19 lakes were collected between July and August 2009 along a 90 km east-west transect and analyzed for grain size, organic matter, nutrients, and metals. The work was undertaken to establish a dataset to contribute to the determination of natural variability of arsenic in freshwater sediments in the Yellowknife area, Northwest Territories. Geochemistry results of lake sediments are compared to previous work, bedrock geochemistry where available, and the Canadian Council of Ministers of the Environment Interim Sediment Quality Guidelines and Probable Effects Levels for the Protection of Aquatic Life. Concentrations of arsenic in bulk lake sediment samples are elevated above Interim Sediment Quality Quidelines and Probable Effects Levels in lakes located west of the City of Yellowknife. These lakes occur on granitoid bedrock, which contain low arsenic relative to other bedrock types in the study region. The spatial pattern of arsenic in lake sediments is consistent with aerial dispersion of emitted particulates from mine smelting point sources and transportation by prevailing winds west of the City of Yellowknife.

Elliott, S.M., Roe, H.M., Patterson, R.T., 2012. Testate amoebae as indicators of hydroseral change: An 8500 year record from Mer Bleue Bog, eastern Ontario, Canada. Quaternary International. v. 268, p. 128-144. https://doi.org/10.1016/j.quaint.2011.08.020

Testate amoebae have been used widely as a proxy of hydrological change in ombrotrophic peatlands, although their response to abiotic controls in other types of mire and fenland palaeo-environments isless well understood. This paper examines the response of testate amoebae to hydroseral and other environmental changes at Mer Bleue Bog, Ontario, Canada, a large ombrotrophic peatland, which evolved from a brackish-water embayment in the early Holocene. Sediments, plant macrofossils and diatoms examined from a 5.99 m core collected from the dome of the bog record six stages of development: i) a quiet, brackish-water riverine phase (prior to ca. 8500 cal BP); ii) a shallow lake (ca. 8500-8200 cal BP); iii) fen (8200-7600 cal BP); iv) transitional mire (7600-6900 cal BP); v) pioneer raised mire (6900-4450 cal BP); and vi) ombrotrophic bog (4450 cal BP-present). Testate amoebae, notably small (<25 mm diameter) specimens of Centropyxis aculeata type, first appear in low abundances in sediments ascribed to the lacustrine phase. Diatoms from the same horizons record a shallowing in water depth, a decline in salinity and the development of emergent macrophytic vegetation, which may have provided favourable conditions for testate amoeba colonization. The testate amoeba communities of the inferred fen phase are more diverse and include centropyxids, cyclopyxids, Arcellidae and Hyalospheniidae, although the assemblages show some differences to those recently reported in modern European fen environments. The FeneBog Transition (FBT) is also dominated by C. aculeata type. The change in testate amoeba communities around this key transition is apparent in the results of Detrended Correspondence Analysis (DCA), and appears to reflect a latent nutrient gradient and a secondary moisture gradient. DCA analyses of plant macrofossil remains around the FBT show a similar trend, although the sensitivity of the two proxies to the inferred environmental changes differs. Comparisons with other regional mid-Holocene peatland records confirm the important influence of reduced effective precipitation on the testate amoeba communities during the initiation and development of Sphagnum-dominated, raised bog communities.

Galloway, J.M., Sanei H, Patterson R.T., Mosstajiri, Hadlari T., Falck, H., 2012. Total arsenic concentrations of lake sediments near the City of Yellowknife, Northwest Territories. Geological Survey of Canada Open File 7037, 47 p. https://doi.org/10.4095/289911

We report on recent geoscience data collected by the Geological Survey of Canada in collaboration with Northwest Territories Geoscience Office and Carleton University. Fifty sediment-water interface samples from 19 lakes were collected between July and August 2009 along a 90 km east-west transect and analyzed for grain size, organic matter, nutrients, and metals. The work was undertaken to establish a dataset to contribute to the determination of natural variability of arsenic in freshwater sediments in the Yellowknife area, Northwest Territories. Geochemistry results of lake sediments are compared to previous work, bedrock geochemistry where available, and the Canadian Council of Ministers of the Environment Interim Sediment Quality Guidelines and Probable Effects Levels for the Protection of Aquatic Life. Concentrations of arsenic in bulk lake sediment samples are elevated above Interim Sediment Quality Quidelines and Probable Effects Levels in lakes located west of the City of Yellowknife. These lakes occur on granitoid bedrock, which contain low arsenic relative to other bedrock types in the study region. The spatial pattern of arsenic in lake sediments is consistent with aerial dispersion of emitted particulates from mine smelting point sources and transportation by prevailing winds west of the City of Yellowknife.

El Bilali, H, Patterson, R.T., 2012. Influence of cellulose oxygen isotope variability in sub-fossil Sphagnumand plant macrofossil components on the reliability of paleoclimate records at the Mer Bleue Bog, Ottawa, Ontario, Canada. Organic Geochemistry, v. 43, p. 39-49. doi: 10.1016/j.orggeochem.2011.11.003

This study provides a new understanding of cellulose oxygen (δ18O_cel) isotopic variability in various plant macrofossils, particularly Sphagnum, derived from an ∼9200year succession of Holocene peat in Mer Bleue Bog, Ottawa, Ontario, Canada. The variation of δ18O_cel isotopic composition, commonly used as a proxy of paleotemperature and paleoprecipitation, was compared between (1) Sphagnum and other plant macrofossils down core and (2) Sphagnum species within and between samples. The most common Sphagnum species encountered was Sphagnum magellanicum von Bridel, 1798 with lesser amounts of Sphagnum capillifolium (Breutel) Steudel, 1824, Sphagnum fuscum Klinggräff, 1872 and Sphagnum angustifolium Jensen, 1896. There is a statistically significant offset in δ18O_cel isotopic values (mean offset: 1.6‰, standard deviation=3.2‰, n=19) obtained from Sphagnum in comparison with values obtained from other plant macrofossils, particularly rhizomes. The δ18O_cel isotopic offset (mean offset: 0.1‰, standard deviation=1.0‰, n=11) between Sphagnum specimens from the same core horizons, irrespective of the species analyzed, was statistically insignificant at >95%. These results indicate that δ18O_cel isotopic analysis of bulk peat material with high percentage of rhizome and other vascular plants could result in erroneous paleoclimate reconstructions.

Macumber, A.L., Neville, L.A., Galloway, J.M., Patterson, R.T., Falck, H., Swindles, G.T., Crann, C., Clark, I., Gammon, P., Madsen, E. 2012. Climatological assessment of the Northwest Territories and implications for the long-term viability of the Tibbitt to Contwoyto Winter Road, Part II: March 2010 Field Season. NWT Open Report 2011-010, 83 p. https://doi.org/10.1016/j.quaint.2012.08.1132

We characterize water quality and present biological and chemical data from lake sediments in support of an NSERC Strategic Project mandated to investigate background climate variability over the past ca. 3500 years in the southern Northwest Territories (NT). Goals of the project “Paleoclimatological assessment of the central Northwest Territories: Implications for the long-term viability of the Tibbitt to Contwoyto Winter Ice Road” include providing data to increase the understanding of natural climate variability in the southern NT in general, and the Tibbitt to Contwoyto Winter Road (TCWR) in particular. A complete understanding of past climate systems is critical to predicting future climate variability and impacts on northern ecosystems.

Eighteen lakes were sampled during March 2010 (Appendix C – Table C01): a total of thirteen freeze cores, sixty Glew cores, twenty sediment-water interface samples, twenty bottom and top water samples and twenty vertical lake profiles were collected. The eighteen lakes samples are spread along a latitudinal transect that spans the length of the TCWR from Tibbitt Lake to Lac de Gras. Lake sediment cores are composed mainly of mud, although a few contain intervals of sand and gravel. Freeze coring was performed with a custom designed device that captured sediments on two faces and was successful in capturing the unconsolidated sediment-water interface. Sediment cores were digitally imaged and sedimentologically described and a subset was X-Ray imaged. Limnological properties and chemical characterization of lake water will be used in concert with analyses of sediment-water interface samples to develop thecamoebian (arcellacean) and diatom-based transfer functions. These transfer functions will be used to quantify the paleoclimate record of the central NT over the past 3000 years. This research represents the first analysis of fossil and modern assemblages of arcellaceans in the southern NT and is only the second investigation involving arcellaceans, after Dallimore et al. (2000), to occur in the territory. Other microfossil techniques, such as palynology and microscopic charcoal analysis, will permit reconstruction of treeline movement and the response of fire regime to past climate change.

Swindles, G.T., Patterson, R.T., Roe, H.M., Galloway, J.M., 2012. Evaluating periocidities in peat-based climate proxy records. Quaternary Science Reviews. v. 41, p. 94-103. https://doi.org/10.1016/j.quascirev.2012.03.003

Proxy records derived from ombrotrophic peatlands provide important insights into climate change over decadal to millennial timescales. We present mid- to late- Holocene humification data and testate amoebae-derived water table records from two peatlands in Northern Ireland.  We examine the replication of periodicities in these proxy climate records which have been precisely linked through tephrochronology. Age-depth models were constructed using a Bayesian piece-wise linear accumulation model and chronological errors were calculated for each profile. A Lomb-Scargle Fourier transform-based spectral analysis is used to test for statistically significant periodicities in the data. Periodicities of c. 130, 180, 260, 540 and 1160 years are present in at least one proxy records in each site. The replication of these periodicities provides persuasive evidence that they are a product of allogenic climate controls, rather than internal peatland dynamics. A technique to estimate the possible level of red noise in the data is applied and demonstrates that these periodicities cannot be explained by a first-order autoregressive model. We evaluate the periodicities with a review of those reported previously from marine and terrestrial climate proxy data and put into the context of climate forcing parameters.

Patterson, R.T., Roe, H.M., Swindles, G.T., 2012. Development of an Arcellacea (testate lobose amoebae) based transfer function for sedimentary phosphorus in lakes. Palaeogeography, Paleoclimatology, Palaeoecology. v. 348-349, p. 32-44. https://doi.org/10.1016/j.palaeo.2012.05.028

Arcellacea (testate lobose amoebae) communities were assessed from 73 sediment-water interface samples collected from 33 lakes in urban and rural settings within the Greater Toronto Area (GTA), Ontario, Canada, as well as from forested control areas in the Lake Simcoe area, Algonquin Park and eastern Ontario. The results were used to: (1) develop a statistically rigorous arcellacean-based training set for sedimentary phosphorus (Olsen P (OP)) loading; and (2) derive a transfer function to reconstruct OP levels during the post-European settlement era (AD1870s onward) using a chronologically well-constrained core from Haynes Lake on the environmentally sensitive Oak Ridges Moraine, within the GTA. Ordination analysis indicated that OP most influenced arcellacean assemblages, explaining 6.5% (p<0.005) of total variance. An improved training set where the influence of other important environmental variables (e.g. total organic carbon, total nitrogen, Mg) was reduced, comprised 40 samples from 31 lakes, and was used to construct the first published transfer function for lacustrine arcellaceans using tolerance downweighted weighted averaging (WA-Tol) with inverse deshrinking (RMSEPjack-77 pp; r²jack=0.68). The inferred reconstruction indicates that OP levels remained near pre-settlement background levels from settlement in the late AD 1870’s through to the early AD 1970’s. Since OP runoff from both forests and pasture is minimal, early agricultural land use within the lake catchment was as most likely pasture and/or was used to grow perennial crops such as Timothy-grass for hay. A significant increase in inferred OP concentration beginning ~AD 1972 may have been related to a change in crops (e.g corn production) in the catchment resulting in more runoff, and the introduction of chemical fertilizers. A dramatic decline in OP after ~AD 1985 probably corresponds to a reduction in chemical fertilizer use related to advances in agronomy, which permitted a more precise control over required fertilizer application. Another significant increase in OP levels after ~AD 1995 may have been related to the construction of a large golf course upslope and immediately to the north of Haynes Lake in AD 1993, where significant fertilizer use is required to maintain the fairways. These results demonstrate that arcellaceans have great potential for reconstructing lake water geochemistry and will complement other proxies (e.g. diatoms) in paleolimnological research.

Neville, L.A., Gammon, P., Patterson , R.T., McCarthy, F.M.G., MacKinnon, M.D., Macumber, A.L. 2012. Response of benthic microorganisms (thecamoebians) to oil sands process-affected materials; providing endpoints for gauging aquatic reclamation success. Third International Oil Sands Tailings Conference. D. Sego, G.W. Wilson, N.Beier (Eds). Edmonton, AB, p. 369-377. https://doi.org/10.2113/gsjfr.41.3.230

Constructed wetlands and end-pit lakes will play an important role in reclamation options for fluid tailings (OSPW/M) at surface oil sands operations. Through time and with natural bioremediation viable aquatic habitats will develop, but currently few tools are available to determine the rates of remediation in produced ecosystems. A micropaleoecological environmental proxy (thecamoebians) has been demonstrated to provide a time-averaged indicator of ecosystem health. Thecamoebian communities in sediments from both impacted and non-impacted wetlands and lakes in the vicinity of oil sands operation have been compared. An index of response to stress has been compiled with the goal of using it as a predictor of the path of remediation that will produce sustainable ecosystems. This information also provides an endpoint for remediation efforts. Thecamoebian assemblages in cores and surface samples from 63 natural lakes across the region were used to establish natural ecological ranges and remediation targets. These were compared to those present in wetland sediments impacted by oil sands materials (OSPW/M). The process-affected sites had lower thecamoebian diversity and were dominated by centropyxid taxa, whereas more abundant and diverse assemblages dominated by difflugid taxa characterized less-impacted sites. Moreover, assemblages responded quickly to changes in OSPW/M input and to various reclamation strategies, such as nutrient input. Preliminary results suggest that thecamoebians represent proxies for gauging ecosystem health, monitoring aquatic reclamation progression and developing target endpoints.

Mertens, K.N., Bringué, M., Van Nieuwenhove, N., Takano, Y., Pospelova, V., Rochon, A., de Vernal, A., Radi, T., Dale, B., Patterson, R.T., Weckström, K., Andrén, E., Louwye, S., Matsuoka, K. 2012. Process length variation of the cyst of the dinoflagellate Protoceratium reticulatum in the North Pacific and Baltic-Skagerrak region: calibration as annual density proxy and first evidence of pseudo-cryptic speciation. Journal of Quaternary Science. v. 27 (7), p. 734-744. DOI: 10.1002/jqs.2564.

We investigated the process length variation of cysts of Protoceratium reticulatum in surface sediments from the North Pacific. Average process length showed a significant inverse relation to annual sea water density, σt annual =1000 + (3.5184 x average process length – 6.686) (R²=0.87). A sediment trap study from Effingham Inlet (British Columbia) shows the same relation of average process length to local sea water density variations. This calibration cannot be reconciled with a calibration from the Baltic-Skaggerak, accentuating the regional character of these calibrations.

Macumber, A.L., Patterson, R.T.,Neville, L.A., Falck, H., 2011. A sledge microtome for high resolution subsampling of freeze cores. Journal of Paleolimnology, v. 45, p. 307-310. DOI 10.1007/s10933-010-9487-4.

We describe a sledge microtome designed for the high-resolution subsampling of freeze cores. This inexpensive freeze-core microtome is capable of producing precise subsamples at mm to sub-mm resolution without sediment loss and cross-contamination. Such a subsampling resolution permits recognition of sub-decadal to annual events even in systems with low sedimentation rates. The freeze-core microtome is particularly useful for obtaining high-resolution subsamples at the environmentally important sediment-water interface due to freeze corers being capable of capturing this boundary with minimal disturbance as compared to other coring methods.

Patterson, R.T., Swindles, G.T., Roe, H.M., Kumar, A., Prokoph, A. 2011. Dinoflagellate cyst-based reconstructions of mid to late Holocene winter sea-surface temperature and productivity from an anoxic fjord in the NE Pacific Ocean. Quaternary International. v. 235, p. 13-25. https://doi.org/10.1016/j.quaint.2010.06.016

Published contemporary dinoflagellate distributional data from the NE Pacific margin and estuarine environments (n = 136) were re-analyzed using Canonical Correspondence Analysis (CCA) and partial Canonical Correspondence Analysis (pCCA). These analyses illustrated the dominant controls of winter temperature and productivity on the distribution of dinoflagellate cysts in this region. Dinoflagellate cyst-based predictive models for winter temperature and productivity were developed from the contemporary distributional data using the modern analogue technique and applied to subfossil data from two mid to late Holocene (w5500 calendar years before presentepresent) cores; TUL99B03 and TUL99B11, collected from Effingham Inlet, a 15 km long anoxic fjord located on the southwest coast of Vancouver Island that directly opens to the Pacific Ocean through Barkley Sound. Sedimentation within these basins largely comprises annually deposited laminated couplets, each made up of a winter deposited terrigenous layer and spring to fall deposited diatomaceous layer. The Effingham Inlet dinoflagellate cyst record provides evidence of a mid-Holocene gradual decline in winter SST, ending with the initiation of neoglacial advances in the region by ~3500 cal BP. A reconstructed Late Holocene increase in winter SST was initiated by a weakening of the California Current, which would have resulted in a warmer central gyre and more El Niño-like conditions.