NOVELTY - A transgenic algae (A1) capable of modulating peripheral (PSII) antenna size in response to ambient light intensity, is new, where the transgenic algae exhibit an increase in Chlorophyll a/b (Chi a/b) ratios when grown under high light conditions, and a decrease in Chi a/b ratios when grown under low light conditions compared to wild type cells grown under identical conditions.    USE - As transgenic algae for the production of bio-oil or bio-diesel, and beta-carotene, lutein or zeaxanthin (claimed).    ADVANTAGE - The transgenic algae is capable of modulating peripheral (PSII) antenna size in response to ambient light intensity; disrupts or suppresses endogenous chlorophyll a oxidase (CAO) gene; exhibits an increase in Chi a/b ratios when grown under high light conditions, and a decrease in Chi a/b ratios when grown under low light conditions compared to wild type cells grown under identical conditions, where the increase in Chi a/b ratio is at least 5% greater than observed with wild type cells; exhibits an increase in biomass production compared to wild type algae grown under identical conditions; enhances yields of photosynthetic productivity under conditions of high light intensity and/or high density growth; enhances bio-oil or bio-diesel production, and beta-carotene, lutein or zeaxanthin production; and provides improved production systems with higher flexibility in growth conditions.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) preparation of the transgenic algae (A1);    (2) enhancing yields of photosynthetic productivity under conditions of high light intensity, and/or high density growth, involving providing a photosynthetic organism comprising a heterologous polynucleotide sequence containing expression control sequences having a cold-shock domain consensus sequence (CSDDCS) motif operatively coupled to a polynucleotide sequence encoding chlorophyll a oxidase (CAO), where expression of the CAO is increased at low light intensity, compared to the expression of the CAO at high light intensity, and cultivating the photosynthetic organism at high light intensity and/or high density;    (3) enhancing bio-oil or bio-diesel production, and beta-carotene, lutein or zeaxanthin production from a photosynthetic organism, involving providing algae comprising a heterologous polynucleotide sequence containing expression control sequences having CSDDCS motif operatively coupled to a polynucleotide sequence encoding CAO, where expression of the CAO is increased at low light intensity, compared to the expression of the CAO at high light intensity, and cultivating the algae at high light intensity and/or high density;    (4) new expression vector comprising expression control sequences having a cold-shock domain consensus sequence (CSDDCS) motif operatively coupled to a polynucleotide sequence encoding CAO.