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Enteric methane emissions are the single largest source of direct greenhouse gas emissions (GHG) in beef and dairy value chains and a substantial contributor to anthropogenic methane emissions globally. In late 2019, the World Wildlife Fund (WWF), the Advanced Research Projects Agency-Energy (ARPA-E) and the Foundation for Food and Agriculture Research (FFAR) convened approximately 50 stakeholders representing research and production of seaweeds, animal feeds, dairy cattle, and beef and dairy foods to discuss challenges and opportunities associated with the use of seaweed-based ingredients to reduce enteric methane emissions. This Perspective article describes the considerations identified by the workshop participants and suggests next steps for the further development and evaluation of seaweed-based feed ingredients as enteric methane mitigants. Although numerous compounds derived from sources other than seaweed have been identified as having enteric methane mitigation potential, these mitigants are outside the scope of this article.

Despite the heightened awareness of ocean acidification (OA) effects on marine organisms, few studies empirically juxtapose biological responses to CO2 manipulations across functionally distinct primary producers, particularly benthic algae. Algal responses to OA may vary because increasing CO2 has the potential to fertilize photosynthesis but impair biomineralization. Using a series of repeated experiments on Palmyra Atoll, simulated OA effects were tested across a suite of ecologically important coral reef algae, including five fleshy and six calcareous species. Growth, calcification and photophysiology were measured for each species independently and metrics were combined from each experiment using a meta-analysis to examine overall trends across functional groups categorized as fleshy, upright calcareous, and crustose coralline algae (CCA). The magnitude of the effect of OA on algal growth response varied by species, but the direction was consistent within functional groups. Exposure to OA conditions generally enhanced growth in fleshy macroalgae, reduced net calcification in upright calcareous algae, and caused net dissolution in CCA. Additionally, three of the five fleshy seaweeds tested became reproductive upon exposure to OA conditions. There was no consistent effect of OA on algal photophysiology. Our study provides experimental evidence to support the hypothesis that OA will reduce the ability of calcareous algae to biomineralize. Further, we show that CO2 enrichment either will stimulate population or somatic growth in some species of fleshy macroalgae. Thus, our results suggest that projected OA conditions may favor non-calcifying algae and influence the relative dominance of fleshy macroalgae on reefs, perpetuating or exacerbating existing shifts in reef community structure.

The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO(2), reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO(2), often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO(2). Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change.

Biorefinery, hydrocolloid industry, seaweed processor, seaweeds, waste valorization Keywords: biorefinery; hydrocolloid industry; seaweed processor; seaweeds; waste valorization EN biorefinery hydrocolloid industry seaweed processor seaweeds waste valorization 1020 1027 8 06/06/23 20230601 NES 230601 INTRODUCTION An increasing demand for carbon-neutral, sustainable alternatives to petrochemical products has invigorated interests around the industrial utilization of biomass and biomass-derived feedstocks.[[1]] In addition, a closed-loop system in which feed materials and energy are recovered or recycled has been identified as a key framework for facilitating the transition to eco-effective industrial systems, thereby encouraging its widespread adoption across industrial sectors based on different bioresources.[[1]] Seaweeds have been a key subject of extensive investigations with respect to facilitating circular biomass-based economy because of its clear advantages over terrestrial crops.[[2]] In particular, the cultivation potential of seaweeds in large-scale offshore farms has promoted them as a promising candidate for carbon capture with minimal external nutrient requirements and almost zero competition for agricultural land.[[3]] Moreover, seaweeds themselves have considerable economic value not just because of their fast growth rates, but due to their unique chemical composition.[5] As an alternative feedstock to ligno-cellulosic biomass,[3] seaweeds contain a suite of functional ingredients, including polysaccharides, proteins, lipids and polyphenols. Although the availability of each of these waste materials depends on the species and quality of raw seaweed materials being processed and the choice of processing conditions at different facilities,[15] literature survey and personal communications with industry experts indicated that these waste materials could be more than 50% of raw seaweed biomass. [Extracted from the article]

Benthic marine primary producers affect the chemistry of their surrounding environment through metabolic processes. Photosynthesis and respiration will elevate or depress the concentration of oxygen in the diffusive boundary layer. Likewise, acid-base regulation and biomineralization/dissolution for calcifying species can alter the relative concentration of inorganic carbon species and thus pH. Here, we measured the relative ability of several common benthic primary producers from coral reef systems of the central Pacific and the Caribbean to simultaneously affect seawater oxygen concentration and pH values. Repeated measurements over a diel cycle confirmed that several primary producers substantially alter surrounding seawater chemistry over time. The majority of fleshy algae exhibited a stoichiometric ratio of oxygen to hydrogen ions not significantly different from one during daylight hours. In contrast, calcifiers exhibited significantly lower oxygen to hydrogen ion ratios that were unique for each species and were inversely correlated with known rates of calcification. These data provide the first quantitative estimates of the simultaneous influence of several species of benthic primary producers on water column oxygen concentrations and pH across different tropical reef systems. Finally, because more productive fleshy taxa have the potential to raise both oxygen and pH during the day to a greater extent than calcified species, our results suggest that some fleshy taxa may provide a buffering capacity to future ocean acidification scenarios., Introduction Coral reefs are subjected to local anthropogenic stressors [e.g. overfishing, sedimentation; (Nystrom et al. 2000; Bellwood et al. 2004)] as well as global warming and seawater acidification due to [...]

The aim of this study was to evaluate the effects of processed dietary supplements derived from two seaweeds, Saccharina latissima (SL) and Ascophyllum nodosum (AN), on microbial methane production and fermentation profile using in vitro methods. Four dualflow continuous culture fermenters were utilized in a 4x4 Latin Square design to assess these 4 supplements: unwashed, coarsely milled SL (UNW), 3-min rinsed SL (3MR), 20-sec blanched SL (20SB), and a crude phlorotannin extract from AN (PHLT). Treatments were randomly assigned to fermenters and were top dressed on the total mixed ration (TMR) at 5% of total dry matter (DM). Four, 10-d experimental periods were conducted, consisting of a 7-d equilibration period followed by a 3-d sampling period. Vessel pH was continually measured, and effluent samples were collected for volatile fatty acid (VFA) analysis and calculation of DM, organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibilities. Methane was measured prior to the first AM and PM feedings during the 3-d sampling period. Data were analyzed using the PROC MIXED procedure of SAS (9.4) with fermenter as the random effect and period and treatment as fixed effects. Processed treatments (3MR= 7.86, 20SB= 5.75, PHLT= 10.46 mg/dL) yielded less methane (P < 0.02) than unprocessed (UNW= 24.06 mg/dL). Apparent digestibilities of DM, OM, NDF and ADF were not affected by treatment. Total VFA (mM) was greater (P = 0.02) in 3MR than PHLT. The acetate to propionate ratio (A:P) was greater (P < 0.01) in PHLT compared with 20SB, 3MR and UNW (5.62 vs 1.47, 1.27 and 1.54, respectively). Time spent below pH 5.8 during fermentation was not affected by treatment. These results indicate that seaweed processing method can affect methane production in vitro without negatively impacting rumen fermentation and should be further investigated using in vivo models. [ABSTRACT FROM AUTHOR]

Nests of oyster toadfish Opsanus tau with guardian males were transported from Waquoit Bay, Massachusetts, to the Marine Biological Laboratory in Woods Hole, Massachusetts. Following larval detachment from the nest, the offspring were separated from the males and placed into culture tanks with flow-through seawater. The juveniles were initially fed adult brine shrimp Artemia spp. supplemented with small pieces of frozen squid Loligo spp. During the second year of the study, the majority of the diet was squid supplemented with locally available food. Fish were maintained at different temperatures (approximately 15°C, 20°C, and ambient) and densities (2-90 fish/m(²)). Although the culture density did not have an appreciable effect on growth, fish maintained in warmer water grew significantly faster than fish kept at cooler temperatures. After 2 years, the fish reared in warm water averaged 10.0 cm and 40.5 g, while those reared in cold water averaged 6.5 cm and 11.0 g. Growth in weight was shown to be exponential from day 76 to day 200, with rates of 1.4% and 0.38% body weight per day at 20°C and 15°C, respectively, an almost fourfold difference. Beyond day 200, growth in weight at both temperatures was best fitted by a power function; however, there was no significant difference in the slope of the growth curve between the two temperature groups. Thus, temperature did not accelerate growth rates from day 225 onward. Survival rates were greater than 68% in four of the five treatment groups. Despite constant high temperatures and food availability throughout the winter months, oyster toadfish underwent a quiescent period during the second year of life and exhibited minimal growth during this time, indicating that shortened day length may affect growth rates. [ABSTRACT FROM AUTHOR]