mARINE mICROBIOME HABITAT CAPACITY and resilience
Passive benthic substrate conditioning to support natural kelp recovery process
BC Timber Goats, Kelp and Biochar has been leading research into the application of forestry biochar in kelp and marine habitat restoration and in 2024 partnered with the Pacific Urchin Harvesters Association, Vancouver Island Sea Salt, and North Island College to grow kelp on biochar at the NIC lab. Two types of biochar were provided; some that contained seaweed extract and some biochar that was empty. It was clear that the bull kelp sporophytes really popped in the first two weeks on the biochar that contained seaweed extract. Concurrently at the Vancouver Island Sea Salt Company, another experiment was designed that demonstrated biochar naturally absorbing nutrients in an aquarium that received marine nutrients cleaned from the reverse osmosis filters.
Biochar Absorbs nutrients to Induce heat Tolerance
Biochar’s Mechanisms of Heat Tolerance
Recent research into heat tolerance in seaweed has demonstrated seaweed extract and access to nutrients in the gametophyte stage can induce heat tolerance up to 18C. The kelp microbiome, the array of bacteria, viruses and fungi that populate the surface of the Alga has also been demonstrated to be of supreme importance to the health of the alga and under heat stress this microbiome dies off. Biochar with it’s huge surface area can act as a reservoir for the kelp microbiome and augment heat recovery from a heat stress event.
Sea Urhcin Divers sink biochar to improve urchin Feed Stock
Biochar as a supplemental material provides a habitat of resilience
The results from the experiments at North Island College and Vancouver Island Sea Salt suggest that simply adding biochar to a restoration or aquaculture site is enough to provide a habitat of resilience where nutrients are absorbed and the local microbiome can establish and support larger organisms like kelp gametophytes, especially during heat stress events. The Pacific Urchin Harvesters Association is a natural partner to distribute biochar for kelp restoration as they already have the boats and divers and a vested interest in stewarding local kelp and seaweed populations as those are the Sea Urchin’s primary feed source. Bags of biochar can be sent out on empty Urchin boats to distribute throughout the fishing day.
backgroud research
Biochar and Ocean Warming
Ocean Warming and Ocean Acidification are two representative challenges of Kelp Aquaculture.(Zi-min Hu et al., 2021). Even when propagule supply is not limiting, kelp may fail to establish because of localized abiotic or biotic processes affecting settlement or post settlement survival of recruits.(Morris et. al., 2020). The Structural complexity of artificial substrates can greatly influence kelp recruitment (Perkol-Finkel et al. 2012), artificial structures could be ecologically engineered (Chapman and Underwood 2011) to incorporate suitable structural complexity.
A potential solution to overcome heat stress effectively while maintaining growth of kelp species is to use a solution of commercial seaweed extracts (biostimulants), to dip juvenile sporophytes before cultivation in the open sea (Umanzor et al., 2019). Alternatively, providing sufficient nitrogen (i.e. NO3−) can help kelp to ameliorate temperature-dependent responses such as growth and photosynthesis, thus enhancing its tolerance and acclimation ability to thermal stress (Fernández et al. 2020). A study on P. hecatensis (pacific red seaweed) demonstrated that treatment with Sargassum horneri extract (Seaweed Extract)can significantly enhance the species thermal tolerance, growth and biochemical resilience under high temperatures, which is especially important as rising seawater temperatures due to climate change threaten seaweed aquaculture (Kim et al.2024).
Surface Area
An important consideration is the functional surface area of the biochar. The greater the porosity or surface area, the more nutrients can be retained. The surface area is highly dependent on feedstock and operating conditions, and typically an increase in pyrolysis temperature as well as a high feedstock lignin content is associated with high surface areas. Depending on these factors, biochar can have a surface area of between 20 and 130 m2/g (Tomczyk, Sokolowska, & Boguta, 2020).The surface area can be enhanced by methods such as steam activation. This process involves exposing the biochar to high-temperature steam at temperatures between 750˚C and 850˚C and can double the biochar surface area (Shim, Yoo, Ryu, Park, & Jung, 2015). The flame cap kiln method requires quenching with water to stop the combustion process so this method of biochar production has the added benefit of introducing introduce steam to the char.
Algal biomass contains little or no lignin, which enables easy hydrolysis of the biomass for subsequent hydrogen fermentation (Ao Xia a et al., 2015). The addition of Biochar in dark fermentation has increased rate and yield of hydrogen production from 26 % and 41 %, (Tianru Lou et al,. 2024) The mechanisms that boost hydrogen in dark fermentation shed light on advantages biochar can provide as a supplemental material for cultivating kelp gametophytes and sporophytes. Those mechanisms include moderating pH, stimulate the growth of functional microorganisms, moderation of mitigating factors of hydrogen production (biotic and abiotic) and facilitation of electron transfer (Tianru Lou et al,. 2024).
Functional groups and nutrients
Nutrient impregnation
Biochar without post-treatment typically contains only small amounts of nutrients like nitrogen, phosphorous and potassium. Kelp growth requires dissolved Nitrogen in bioavailable forms such as nitrate and ammonium, as well as Phosphorous, Potassium, Calcium, Magnesium, Sulphur, Iron, Iodine, Copper, Boron and Molybdenum (Zhang, et al., 2021).Nutrient impregnation is a common method of improving the effectiveness of biochar as a soil amendment in agriculture, and the same method can be used for kelp cultivation (Osman, et al., 2022).
The critical aspect in question is whether it is more effective to impregnate the biochar with the required bio-stimulants in the hatchery and allowing nutrients to release gradually, or to apply the biochar without impregnation in the marine environment and assess its ability to capture and retain nutrients in the substrate. Studies on this have never been done so to explore this so a Biochar Aquarium was set up at the Vancouver Island Sea Salt Company.