Atelomixis as a possible driving force in the phytoplankton composition of Zirahuén, a warm-monomictic tropical lake

Abstract

The present work reviews our current understanding of the limnology of Lake Zirahue´n and extends this knowledge through an analysis of the phytoplankton, illustrating phenomena that typify monomictic tropical lakes. The analysis reinforces the postulate that atelomixis determines the variation in phytoplankton composition of deep tropical lakes with a monomictic mixing regime. Similarly, it is proposed that an incomplete or partial atelomixis, generating a highly dynamic mixing layer, is a force that possibly drives the selection of algal groups, like the Desmidiaceae, with a high surface area to volume ratio. These organisms, characteristic of tropical lakes, though found in the deep epilimnetic layer, receive sufficient irradiance to support their high photosynthetic rate; their high population density survive thanks to a constant supply of nutrients. Lake Zirahue´n is a particularly relevant case for Mexico, since the low calcium concentration and the trophic level of the lake provide an explanation for the otherwise uncommon presence of desmids in other Mexican lakes, even in lakes that exhibit atelomictic phenomena.

Role of atelomixis in replacement of phytoplankton assemblages in Dom Helvécio Lake, South-East Brazil

“…Atelomixis is one robust water movement occurring once a day (during night) and extending either to whole water column (dry period-full atelomixis) or is restricted to epilimnion (rainy period-partial atelomixis). Similar seasonality was described for other tropical lakes (Figueredo & Giani, 2001;Tavera & Martínez-Almeida, 2005;Townsend, 2006), and its ecological relevance was discussed in detail by Barbosa & Total density of phytoplankton (ind ml…”

“…from samples at 100%, 15% and 1% of incident light of Dom Helvécio Lake, South-East Brazil, in 2002 Differences in nutrient uptake efficiency of different desmids may also play role in replacements at speciesspecific level (Healey & Hendzel, 1988). Finally, this key role of atelomixis on explaining desmids presence in other tropical systems has also been shown for Lake Carioca and for other lakes in the middle Rio Doce region, South-East Brazil (Barbosa & Padisák, 2002), and for Lake Zirahuén, in Central Mexico (Tavera & Martínez-Almeida, 2005).…”

Responses to a warming trend and “El Niño” events in a tropical lake in western Mexico

“…It is a warm-monomictic lake with a brief winter mixing, limited to the coldest weeks of the year (January, 17°C) when surface waters temperatures reach values similar to those of the hypolimnion. Its protected basin, small area, high relative depth (8.6 %) and low Responses to a warming trend and ''El Niño'' events in a tropical lake in western Mexico transparency, determines its short winter mixing and thin epilimnion (5 m) compared to other lakes in central Mexico where mixing extends for 2-3 months, hypolimnetic temperatures are similar to those in spring (March-April) and thermoclines are usually deeper ([10 m) (Alcocer et al 2000;Caballero et al 2013;Tavera and Martinez Almeida 2005). We consider that density driven mixing is very important in this lake as wind fetch is limited by its morphometric characteristics.…”

“…These included the low silica values in January 2009 and the low DIN and SRP values leading to N and P co-limitation in surface waters in May 2009. C. ocellata is a species that flourishes in similar conditions in lake Zirahuen (Tavera and Martinez Almeida 2005), with P and N co-limitation (Bernal Brooks et al 2002) and low silica values (Caballero and Vázquez, unpublished data). The deep water chlorophyll maxima in August 2009 and the high abundance of C. ocellata in the metalimnion during August and October 2009, indicates that under poorly mixed conditions this species is finding higher nutrient availably in the deeper waters as a survival strategy given the low nutrient concentrations in the epilimnion (Davey and Heaney 1989).…”

Limnology of the Crater Lake Cuicocha, Ecuador, a Cold Water Tropical Lake

“…by nocturnal cooling in periods of low density gradients (TALLING, 1969). Increased losses of phytoplankton by sedimentation take place, and the atelomixis leads to a more oligotrophic status of the lake (TAVERA and MARTÍNEZ-ALMEIDA, 2005), who postulated that atelomixis was the driving force in determining phytoplankton composition. In the nearby Lake San Pablo, atelomixis was proved and led to hypolimnic phytoplankton maxima (GUNKEL andCASALLAS, 2002, 2002a).…”