Non-pollen palynomorphs as indicators of water quality in Lake Simcoe, Ontario, Canada

Natural and cultural eutrophication of Sluice Pond, Massachusetts, USA, recorded by algal and protozoan microfossils

“…The exceptional dinocyst record of Sluice Pond is attributed in large part to enhanced preservation, particularly in the deep basin core (Figure 3) where dinocyst concentrations average ~19,500 cysts/mL (range ~2700-63,000 cysts/mL) (Table 1). Low DO concentrations resulting from stratification have been found to promote the preservation of dinocysts in other meromictic lakes like Crawford Lake (Krueger, 2012;McCarthy and Krueger, 2013), and anoxia resulting from increased biochemical oxygen demand (BOD) because of cultural eutrophication promoted dinocyst preservation even in holomictic lakes like Georgian Bay and Lake Simcoe (Danesh et al, 2013;McCarthy et al, 2011;Volik, 2014). The much lower concentrations of dinocysts prior to anthropogenic impact and cultural eutrophication (average ~3800 cysts/ mL, range ~1400-9750 cysts/mL) and the abundance of P. cf.…”

“…In contrast, other non-pollen palynomorphs (e.g. Pediastrum, desmids) are relatively sparse in Sluice Pond compared with other sites, such as Crawford Lake (McCarthy and Krueger, 2013), Lake Simcoe (Danesh et al, 2013;Volik, 2014), and small lakes in the Penetanguishene region of Ontario (Burden et al, 1986). 2004) for New England and Shannon Diversity Index (SDI) for both microfossil groups, and stippling identifies oxygen-depleted zones.…”

“…P. willei) in various lakes in Ontario, when nutrient concentrations increased (e.g. Burden et al, 1986;Danesh et al, 2013;Krueger, 2012;McCarthy and Krueger, 2013;McCarthy et al, 2011;Volik, 2014). Additionally, spring blooms with densities of thecae of P. gatunense exceeding 1000 cells/mL (c. 300 mg chlorophyll/m 3 ) are associated with high nutrient flux in Lake Kinneret (Sukenik et al, 2002;Zohary et al, 2012).…”

“…Dinoflagellates reach optimal growth during times of high illumination, nutrient levels, and temperature (Taylor, 1987), and some taxa form fossilizable resting cysts when conditions become sub-optimal. Cysts of freshwater dinoflagellates have been found in palynological preparations in sediments as old as Oligocene (Traverse, 1955) and are quite common in Holocene sediments (Boyko, 1973; Boyko-Diakonow, 1979; Chu et al, 2008; Dale et al, 1999; Danesh et al, 2013; McCarthy and Krueger, 2013; Norris and McAndrews, 1970; Tardio et al, 2006a, 2006b), but they have mostly been ignored in paleolimnological studies. This is largely because of their poorly understood taxonomy, with resting cysts described for only 84 of the ~350 dinoflagellate species known from freshwater environments (Mertens et al, 2012).…”

“…This is largely because of their poorly understood taxonomy, with resting cysts described for only 84 of the ~350 dinoflagellate species known from freshwater environments (Mertens et al, 2012). Cysts attributed to the genera Peridinium Ehrenberg and Parvodinium Carty have recently been shown to reflect natural and anthropogenic change (principally eutrophication) in the water column of eastern North American lakes (Burden et al, 1986; Danesh et al, 2013; Krueger, 2012; McCarthy and Krueger, 2013; McCarthy et al, 2011; Volik, 2014; Zippi et al, 1990, 1991), illustrating their potential as paleolimnological proxies.…”