Temporal variation of phytoplankton in a small tropical crater lake, Costa Rica

Abstract

Abstract:The temporal variation in lake's phytoplankton is important to understand its general biodiversity. For tropical lakes, it has been hypothesized that they follow a similar pattern as temperate ones, on a much accelerated pace; nevertheless, few case studies have tried to elucidate this. Most studies in Costa Rica have used a monthly sampling scheme and failed in showing the expected changes. In this study, the phytoplankton of the small Barvas's crater lake was followed for more than three years, first with monthly and later with weekly samplings, that covered almost two years. Additional information on temperature and oxygen vertical profiles was obtained on a monthly basis, and surface temperature was measured during weekly samplings around noon. Results showed that in spite of its shallow condition (max. depth: 7m) and low surface temperature (11 to 19°C), the lake stratifies at least for brief periods. The phytoplankton showed both, rapid change periods, and prolonged ones of relative stasis. The plankton composition fluctuated between three main phases, one characterized by the abundance of small sized desmids (Staurastrum paradoxum, Cosmarium asphaerosporum), a second phase dominated by equally small cryptomonads (Chryptochrysis minor, Chroomonas sp.) and a third phase dominated by the green alga Eutetramorus tetrasporus. Although data evidenced that monthly sampling could miss short term events, the temporal variation did not follow the typical dry and rainy seasons of the region, or any particular annual pattern. Year to year variation was high. As this small lake is located at the summit of Barva Volcano and receives the influence from both the Caribbean and the Pacific weather, seasonality at the lake is not clearly defined as in the rest of the country and short term variations in the local weather might have a stronger effect than broad seasonal trends. The occurrence of this short term changes in the phytoplankton of small tropical lakes in response to weather variations needs to be further explored in other lakes. Rev. Biol. Trop. 58 (4): 1405-1419. Epub 2010 December 01.

Rapid Changes in the Phytoplankton Community of a Subtropical, Shallow, Hypereutrophic Lake During the Rainy Season

“…Additionally, the findings of this study suggest that significant rainfall variations cause extreme seasonal surface runoff and rapid changes in the water quality (Chlorophyll- a , DO, NH 4 + , and NO 3 – ) of this subtropical lake, as well as rapid variations in the phytoplankton community ( Figures 3 , 2 , 5 , 7 ). Studies on the temporal variations in the phytoplankton community have been carried out in temperate regions, but only a few have been reported in tropical or subtropical regions, such as Lake Cajititlán ( Limón-Macias et al, 1983 ; Umaña-Villalobos, 2010 ; Riediger et al, 2015 ; Li et al, 2018 ; Ma et al, 2019 ; Quevedo-Castro et al, 2019 ). The wet season in tropical and subtropical areas exacerbates the cultural eutrophication of surface water bodies when there is intensive agricultural activity in their basin ( Barbosa, 2009 ; Cunha et al, 2013 ).…”

Plankton variation in Río Cuarto Lake, Costa Rica (2013-2017)

“…However, as precipitation and wind are the main seasonal drivers of change in the tropics (Lewis, 1996), and these affect the stratification of the lakes, even at short times scales (Talling & Lemoalle, 1998), other authors have found that there are shifts in the species composition according to shifts in precipitation (Figueredo & Giani, 2001;González, Ortaz, Peñaherrera, & Matos, 2004). In other Costa Rican lakes, where phytoplankton composition has been evaluated weekly for at least one year (Arenal, Barva, Fraijanes, Bonilla), the situation has shown that this sequence not always occurs, and that changes are mainly in the relative contribution of dominant species, rather than a complete change in species composition (Umaña & Collado, 1990;Umaña-Villalobos, 2010, 2014, 2016. Lopez, Bicudo, and Ferragut (2005) also found a shift in relative contribution of a few dominant species in a shallow subtropical reservoir in Brazil, and González et al (2004) also reported a similar pattern of small changes in the relative contribution of a few dominant species in El Salto Reservoir, Venezuela.…”

“…In Costa Rica there are a few studies focused on zooplankton variations. For example, in Fraijanes Lake there is a study about zooplankton variations for one year (Umaña-Villalobos, Avilés-Vargas, & Esquivel-Garrote, 2018) and in Barva Lake there is a study about the phytoplankton variations for one year (Umaña-Villalobos, 2010).…”

Rotifera of various aquatic environments of Costa Rica in reference toCentral American rotifer fauna

“…Studies on marine environments prevail in Costa Rica (Suárez- Morales and Gasca, 1989;Morales and Vargas, 1995;Brugnoli-Olivera et al 2004;Morales-Ramírez et al, 2014;Décima et al, 2016), while our knowledge of inland waters is based on only very few studies. Some data exist on phytoplankton (Haberyan et al, 1995;Umaña, 2001;Umaña-Villalobos, 2010;Landry et al, 2016). However, information on animal plankton is still very scarce (Dumont, 1994;Morales-Ramírez et al, 2014).…”