Investigation of the decline of Ulva prolifera in the Subei Shoal and Qingdao based on physiological changes

Massive Ulva Green Tides Caused by Inhibition of Biomass Allocation to Sporulation

“…Practically, only the intrinsic traits involved in the increase phase, such as high growth rates or multiple reproduction modes, have been highlighted [3,26]. Recently, a few works examined the decline phase of the U. prolifera green tide in the Yellow Sea [10]. However, little coverage has been given to the allocation to sporulation.…”

“…This growth characteristic is obviously different from that of the U. prolifera strain from the attached population, which cannot grow over 10 cm at ≥20 • C (Figure 3). However, the bloom-forming U. prolifera seems to allocate its biomass to sporulation around 25 • C, because it was observed that the green tide population began to decline at 25 • C from July to August [10].…”

“…The attached populations in temperate regions are regularly present in early spring, increase to a maximum in late spring, and rapidly decrease through summer, showing a unimodal pattern of biomass fluctuation (Figure 2A) [6][7][8][9]. The summer decline of the attached populations occurs markedly at 20-25 • C. However, green tide species peak in biomass in the summer [10] and occasionally continue to grow [11]. Such a temporal difference of thallus growth pattern between attached populations and floating green tide populations has not received much attention in the literature.…”