 However, it remains unclear whether these D-amino acids are synthesized by the organisms themselves or absorbed from the seawater. D-amino acids have been detected in plants as well (Brckner and Westhauser, 2003).
<clarity>  However, it remains unclear whether these D-amino acids are synthesized by the organisms themselves or absorbed from the seawater. D-amino acids have been detected in plants as well (Brckner and Westhauser, 2003).
 However, it remains unclear whether these D-amino acids are synthesized by the organisms themselves . They have also been identified in plants (Brckner and Westhauser, 2003).