Mechanical Disintegration and Particle Size Sieving of Chondrus crispus (Irish Moss) Gametophytes and Their Effect on Carrageenan and Phycoerythrin Extraction

To better understand the migration properties of hybrid carrageenan from the seaweed tissue during carrageenan extraction, the effect of increasing the seaweed surface area by the mechanical disintegration of gametophyte Chondrus crispus chips was studied under various temperature and time extraction conditions. Dried Chondrus crispus seaweed chips were milled by a rotor beater mill and classified into eight different size fractions by sieving with varying mesh sizes from 50 to 2000 μm. During extraction at 22 °C, the red color of the filtrate increased significantly with the decreasing particle size of the fraction, correlating with the increasing phycoerythrin concentration (from 0.26 mg PE/g dry seaweed in the >2000 μm size fraction to 2.30 mg PE/g dry seaweed in the <50 μm size fraction). On the other hand, under the same extraction conditions, only a small increase in carrageenan precipitate was obtained with the decreasing size fractions (from no recovery in the >2000 μm size fraction to 2.1 ± 0.1 g/kg filtrate in the <50 μm size fraction). This yield was significantly lower than the ones from extractions at 45 °C (5.4 ± 0.1 g/kg) or at 90 °C (9.9 ± 2.1 g/kg) for the same particle size and time conditions. It could be concluded that hybrid carrageenan extraction is not surface area dependent, while phycoerythrin is. Therefore, it seems that phycoerythrin and carrageenan extraction follow different mechanisms. This creates potential for the selective extraction of each of those two compounds.

The positive effect of coexisting ecosystem engineers: a unique seaweed-mussel association provides refuge for native mud crabs against a non-indigenous predator

In marine sedimentary bottoms, mussels and macroalgae have long been recognized as important autogenic engineers that create habitat and modify abiotic conditions. The structural complexity added by bivalves and macroalgae may also mediate intraguild predation amongst marine decapod crustaceans. While spatial distributions of these ecosystem engineers frequently overlap, there is limited understanding of compounded effects when more than one engineer is present. Here we demonstrate that the coexistence of two ecosystem engineers may create habitat valuable for the survival of a small native species, the Atlantic mud crab (Panopeus herbstii), in the presence of the invasive green crab (Carcinus maenas). Using laboratory and field habitat mimics, we measured mud crab survival rates as a proxy for refuge quality. We compared the refuge provided by a unique association between shells of blue mussels (Mytilus edulis) and the giant strain of Irish moss (Chondrus crispus) to that provided by bare substrate, and by each engineer alone. These experiments revealed that the association of giant Irish moss with blue mussel shells positively and non-additively increased mud crab survival compared to the other less complex habitat mimics. In contrast, parallel experiments revealed that high habitat complexity was less important for young green crabs to survive predation from large conspecifics. These results suggest that the impact of ecosystem engineers on trophic dynamics should be considered in a broader, whole-community context encompassing multiple habitat-forming species present.

A Comparison of Physical Soil Organic Matter Fractionation Methods for Amended Soils

Selecting a suitable physical fractionation method, to investigate soil organic matter dynamics, from the plethora that are available is a difficult task. Using five different physical fractionation methods, on soils either nontreated or with a history of amendment with a range of exogenous organic matter inputs (Irish moss peat; composted horse manure; garden compost) and a resulting range of carbon contents (6.8 to 22.2%), we show that method selection had a significant impact on both the total C recovered and the distribution of the recovered C between unprotected, physically protected, or chemically protected conceptual pools. These between-method differences most likely resulted from the following: (i) variation in the methodological fractions obtained (i.e., distinguishing between aggregate size classes); (ii) their subsequent designation to conceptual pools (e.g., protected versus unprotected); and (iii) the procedures used in sample pretreatment and subsequent aggregate dispersion and fractionation steps. The performance of each method also varied depending on the amendment in question. The findings emphasise the need for an understanding of the nature of the soil samples under investigation, and the stabilisation mechanism of interest, both prior to method selection and when comparing and interpreting findings from literature studies using different fractionation methods.

Commercialization of Irish moss aquaculture: the Canadian experience

Irish moss traditionally has been valued for its hydrocolloid composition. Recognition that natural harvests would not meet the expected demands for its biomass led to experimental pilot-scale cultivation based on principles used in agriculture. Innovative technologies and systems for aquaculture management were devised when those from agriculture or mariculture were not directly transferrable. Periods of rapid progress and of consolidation due to disruptive external events were encountered, a cycle not uncommon during the introduction of a new technology. Certain key decisions in the background matrix that ultimately led to Irish moss cultivation are reviewed together with an overview of the main critical events that affected progress. The Chondrus crispus aquaculture as practiced today is essentially a modified form of precision agriculture operating year-round with c. 3.4 ha of on-land culture tanks and up to 75 employees during the peak season. Beginning with new Irish moss seedstock from the library/nursery, the crop is generated through a closely controlled, vertically integrated system of cultivation that after approximately 18 months increases the biomass more than 50,000-fold. After harvesting it is processed into the final food-grade products to meet the stringent demands of the export market.

Karagenan dan Aplikasinya di Bidang Farmasetika

Karagenan merupakan polisakarida linier tersulfasi dari D-galaktosa dan 3, 6-anhidro-D-galaktosa yang diekstraksi secara komersial dari rumput laut merah kelas Rhodophyceae. Nama karagenan sendiri berasal dari spesies rumput laut yaitu Chondrus crispus yang dikenal sebagai Carrageen Moss atau Irish Moss di Inggris, dan Carraigin di Irlandia. Tiga tipe utama karagenan yang dibedakan berdasakan struktur diantaranya, kappa (κ), iota (ι), dan lambda (λ). Secara komersial karagenan digunakan sebagai agen pengental dan penstabil terutama pada produk makanan dan saus. Selain itu karagenan digunakan pada formulasi farmasetik dan kosmetik sebagai penstabil dalam sistem dispersi, pengatur viskositas dan sebagai pembentuk gel. Dalam bidang farmasetik karagenan banyak digunakan dalam sistem penghantaran obat untuk memperoleh kerja obat yang lebih panjang. Karagenan digunakan sebagai matriks tablet, ektruksi dalam pembuatan pelet, agen pembentuk gel, peningkat viskositas, peningkat permiabilitas dan digunakan pula dalam pembuatan mikrokapsul, beads serta nanopartikel. Selain itu karagenan juga digunakan dalam produksi antibiotik semi sintetik, tetrasiklin, klorotetrasiklin dan asam D-aspartat.Kata kunci: karagenan, aplikasi dalam bidang farmasetik, sistem penghantaran obat

The role of the non-indigenous green crab (Carcinus maenas) in the decline of a unique strain of Irish moss (Chondrus crispus): direct and indirect effects

A unique strain of the red alga Irish moss (Chondrus crispus) is found solely amongst clumps of blue mussels (Mytilus edulis) in a coastal lagoon in Atlantic Canada. Since about 2000, its bed area has shrunk by &gt;99.9%, coinciding with the arrival of the non-indigenous green crab (Carcinus maenas). This study tested two mechanisms by which green crabs may harm the Irish moss. The hypothesis that green crabs directly consume the alga was tested by exposing fronds and clumps to crabs. Crab interaction with the clumps caused limited fragmentation, consumption was very small, and the condition (visible grazing damage) of fronds did not change significantly. A second hypothesis, that during predation and handling of mussels green crabs indirectly displace the seaweed and remove its attachment substrate, was addressed by placing crabs with Irish moss-mussel clumps containing either large or small mussels. Green crabs removed and ate up to 100% of the small mussels but did not consume or displace large mussels. This study concludes that direct consumption is not a plausible mechanism for green crabs to harm this strain. Instead, green crabs harm could be mediated by mussels, whose removal deprives the giant Irish moss of positional stability.

The unique giant Irish moss (Chondrus crispus) from Basin Head: health assessment in relation to reference sites on Prince Edward Island

Irish moss (Chondrus crispus Stackhouse) is a red alga that is common in Atlantic Canada. A unique strain of this species, the giant Irish moss, grows in a single location and is under strict protection. Unlike the common coastal form, the giant Irish moss reproduces solely by fragmentation and is found in gametophyte form. A 99.9% decline in giant Irish moss abundance (1999–2012) prompted this study to address two questions: whether the giant Irish moss remains 100% vegetative and gametophytic, and whether such decline is related to factors leading to a reduction in photosynthetic health. Six populations of the common Irish moss strain were compared with two populations of giant Irish moss, and their life history phases determined using a resorcinol method. The common Irish moss populations exhibited a 65%–86% ratio of gametophytic:tetrasporophytic fronds, while both giant strain populations were 100% gametophytic. Photosynthetic efficiency was measured with Pulse-Amplitude-Modulation (PAM) fluorometry and neither giant moss population had significantly different quantum yield values from the littoral populations. Hence, these analyses provided no evidence of giant Irish moss being exposed to particular sources of stress linked to water or habitat quality and alternative factors explaining the decline of this unique strain are proposed.