Concise review of green algal genus Monostroma Thuret

Abstract

Monostroma (Ulotrichales, Chlorophyta) is the most intensively cultivated genus among green seaweeds, accounting for over 90% of total green algal cultivation. It is commonly found in the eulittoral zones of marine and estuarine habitats, thus contributing significantly to the ecology of the coastal ecosystem. Morphologically, the frond of Monostroma is blade-like with eponymous one-cell thickness; therefore, it is also known as "Slender sea lettuce". Monostroma nitidum is often used for salad ingredients, boiled tsukudani, soups, etc., due to its health benefits. Monostroma kuroshiense is commercially cultivated in East Asia and South America for the edible product "hitoegusa-nori" or "hirohano-hitoegusa nori", popular sushi wraps. This genus remains one of the well-studied seaweed genera for ecophysiology, habitat-dependent seasonality of its growth pattern, gametangial ontogeny and phylogenetics. Moreover, rhamnan sulfate (RS), a sulfated polysaccharide, is the main component of the fiber extracted from M. nitidum and studied for various biological activities. This review presents the taxonomy, morphology, anatomy, life history, distribution, ecology, physiology, cultivation and harvesting, chemical composition, and biotechnological applications of this genus.

Primary production of the kelp Lessonia corrugata varies with season and water motion: Implications for coastal carbon cycling

“…Lessonia corrugata accumulates biomass in seasons with higher nutrient levels and favorable seawater temperatures, such as during winter and spring; this biomass is subsequently lost in the summer. Furthermore, observations from this study and another in this region (Nardelli, Visch, Wright, & Hurd, 2023) have revealed an absence of reproductive tissue (i.e., sorus) in spring, indicating that the majority of available resources at this time can be allocated to biomass growth; this suggests that this species is a “seasonal anticipator” (Kain, 1989; Martins et al., 2022; Navarro et al., 2020; Wiencke et al., 2009). At Coal Point, the average annual NBA was 146.7 g C · m −2 · y −1 , comparable to that of other laminarian species.…”

The endemic kelp Lessonia corrugata is being pushed above its thermal limits in an ocean warming hotspot

“…This raises concerns for the future of this unique, endemic species, as they appear to be highly sensitive to relatively small increases in temperature. It is possible that the species will be at an extinction risk if ocean warming continues at the current rate, with subsequent effects on entire ecosystems and the communities the kelp supports, which themselves have been almost completely unstudied (Hurd et al., 2023; Nardelli, Visch, Wright, et al., 2023). Moreover, recent studies have shown 100% mortality rates of farmed L. corrugata during summer (Nardelli, Visch, Farrington, et al., 2023); the narrow thermal range identified in our study further suggests that L. corrugata may not be suitable for aquaculture in a future, warmer ocean, particularly as temperatures are already reaching close to their thermal limits.…”

“…The kelp Lessonia corrugata is endemic to Tasmania, with a narrow latitudinal and geographic distribution (approx. 40.6–43.6° S; Nardelli, Visch, Wright, et al., 2023, Hurd et al., 2023). It is one of the few dominant species of kelp that supports diverse communities in shallow rocky reef systems along Tasmania's coasts.…”

Taxonomic identification and life cycle comparison of two populations of the monostromatic green algae Monostroma nitidum

“…In view of the polymorphism and life cycle of MGA, scholars have persistently debated the attributes of MGA, leading to prolonged confusion in classification. Based on the presence of intermediate forms of filament, disc, and sac structures during early development of the thallus, as well as considerations of life cycle types, sexual or asexual reproductive modes, classification of MGA has undergone numerous revisions and divisions, resulting in the formation of seven genera (Kaur et al, 2023;Papenfuss, 1960;Tatewaki, 1969): Monostroma, Ulvaria, Ulvopsis, Kornmannia, Protomonostroma, Gayralia, and Capsosiphon (Table 1). (Pellizzari et al, 2013).…”