Global seaweed productivity

Abstract

The magnitude and distribution of net primary production (NPP) in the coastal ocean remains poorly constrained, particularly for shallow marine vegetation. Here, using a compilation of in situ annual NPP measurements across >400 sites in 72 geographic ecoregions, we provide global predictions of the productivity of seaweed habitats, which form the largest vegetated coastal biome on the planet. We find that seaweed NPP is strongly coupled to climatic variables, peaks at temperate latitudes, and is dominated by forests of large brown seaweeds. Seaweed forests exhibit exceptionally high per-area production rates (a global average of 656 and 1711 gC m −2 year −1 in the subtidal and intertidal, respectively), being up to 10 times higher than coastal phytoplankton in temperate and polar seas. Our results show that seaweed NPP is a strong driver of production in the coastal ocean and call for its integration in the oceanic carbon cycle, where it has traditionally been overlooked.

A novel approach reveals underestimation of productivity in the globally important macroalga, Ascophyllum nodosum

“…However, without accurate productivity estimates, it is difficult to assess what harvesting rate should be used in other regions with different productivity levels. Furthermore, because most previous studies have assessed the productivity of A. nodosum based on apical growth alone, its true productivity has been underestimated, and its overall role in coastal and oceanic carbon budgets has been overlooked along with that of seaweeds in general (Pessarrodona et al 2022a). With nearly half of the earth's NPP occurring in the oceans (Field et al 1998) and the urgent need to better understand carbon cycling and more specifically the potential role of seaweed in carbon sequestration (Krause-Jensen et al 2018), obtaining accurate estimates of seaweed productivity will become essential.…”

“…In recent years, the contribution of wild and cultivated seaweed to carbon absorption and sequestration has gained increased attention (Krause-Jensen and Duarte 2016; Duarte et al 2022;Sato et al 2022). Often overlooked in the past, they are now recognized as an important component of the global carbon cycle (Duarte et al 2022) and constitute the largest vegetated coastal biome on the planet (Pessarrodona et al 2022a). It has been recently estimated that macroalgae occupy over 6 million km 2 of the ocean floor, 13,000 km 2 of which are in the intertidal zone, translating into a Net Primary Productivity (NPP) of 8 million t C/y in the intertidal zone alone (Duarte et al 2022).…”

Impact of climate change on Arctic macroalgal communities

“…Kelp forests substantially contribute to the global carbon cycle (Wernberg and Filbee-Dexter, 2018;. The global seaweed productivity (including canopies of brown algae from the orders Laminariales, Fucales, Tilopteridales, and Desmarestiales) has been estimated at 536 ± 31 gC m⁻ ² year⁻ ¹ by Pessarrodona et al (2022).…”

Cultivation and Imaging of S. latissima Embryo Monolayered Cell Sheets Inside Microfluidic Devices

“…Algae are one of these organisms, as they are the oceans’ primary producer and are especially sensitive to increasing temperatures [ 4 ]. Multicellular algae thrive along all coastlines of our planet from the tropics to the polar circles, where they are at the top of the local trophic chain [ 5 ]. The kelp, a group of brown algae, grow to lengths of several metres within a few months, which makes them the most conspicuous seaweeds.…”