Wacklin P, 2006 & Kumar et al. 2011 found higher growth in lower temperature which confirms the findings of this project. Alternatively, Gallina et al. 2011 and many others reported higher growth of cyanobacteria in higher temperature. While Curtis et al. 2008 predicted the impact of global warming on biological entities with latitude in parallel with warming rate.

 

Photosynthesis and pigment analysis

The photosynthetic activity of a species in the field cannot be predicted exclusively from the laboratory experiment; however the laboratory experiment can afford at least to get ideas about field photosynthesis (Demming-adams and Adams 1992). Generally, it is expected that temperature increase and other environmental stress will modify the photosynthetic activity in the field (Powels 1984).  Hanley et al. 1992 reported that the higher temperature and light intensity in the midday have been effective in reducing the photosynthetic activities of intertidal algae. But Jerry et al. 1971 found high photosynthetic activity in lower temperature compared to higher temperature.

 

Kumar et al. 2011 observed gradual increase of pigment concentrations with a temperature rise from 20°C up to 35°C, where the pigment accumulation content was decreased below 20°C and above 40°C. The accumulation of pigment also depends on the light intensity (Liu 1984), quality of light and flow of energy (Mur et al. 1983). Unfortunately, the responses of pigments in Rivularia were observed with temperature and copper treatment.

 

Species composition

Physiologist and ecologists have been attracted for long time to see the effects of physical parameters like temperature on the photosynthetic organisms and their interactions (Helmuth 2009). It is expected to have significant effect on the distribution and composition of marine communities in response to temperature change in sea warming (Fields et al 1993). But the evidence of temperature change in sea water is limited and largely dependent on the correlations between natural changes occurred in sea and abundances of species (Lubchenco et al 1993).

 

Usually, the mechanism of variation in analyzing the species composition is complex and some algae were only identified to genus, not to species because of difficult taxonomy.  Event different strains of one species have variable requirements of temperature and other physiological processes to grow up (Richmond 1988). The abundance of one species in a particular site can be highly sensitive to the interactions of many environmental factors (Menge 2000) like temperature, light intensity, photoperiod, nutrients availability and others where only effects of temperature were studied in this project.

 

Weincke & Dieck 1989 reported that the distribution of macroalgae depends on temperature regimes for growth, reproduction and survival of the specific macroalga species. Snoeijs & Prentice 1989 also found the major changes in the quantitative species composition macroalgae in different temperature with different water flow rate. Snoeijs 1985 had seen increased biomass of microalgae inside the biotest basin throughout the whole year compared. While Hoek 1982 found significant effects of photoperiod in the distribution of algae as the combination of light and dark cycle induce the photosynthesis and respiration.

  

Cladophora and Ceramium

It has been reported that the green algae Cladophora has a competitive advantage compared to other algae, as it has different reproductive alternatives simultaneously (Rosemarin 1982). The low temperature of winter causes disappearance of Cladophora, but a small tuft of root can survive through winter and Cladophora can grow immediately after the winter from the basal roots of previous year (Snoeijs & Prentice 1989). Alternatively, both Keskitalo & Ilus 1987 and Snoeijs & Prentice 1989 reported that Ceramium gobii decreased in abundance in the heated sites compared with colder sites.

 

Ulva

Ulva showed negative abundances with increased temperature in this study, whether Keskitalo & Ilus 1987, Snoeijs 1992 and Snoeijs & Prentice 1989 reported alternative result for Ulva spp. to have increased growth in the heated sites. Snoiejs (1992) also reported that there is no effect of temperature to the growth of Ulva in Forsmark during summer, some species of Ulva are partly replaced by other species of Ulva during mid-summer at Forsmark (Snoeijs & Prentice 1989).