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Marine sponges are set to become more abundant in many near-future oligotrophic environments, where they play crucial roles in nutrient cycling. Of high importance is their mass turnover of dissolved organic matter (DOM), a heterogeneous mixture that constitutes the largest fraction of organic matter in the ocean and is recycled primarily by bacterial mediation. Little is known, however, about the mechanism that enables sponges to incorporate large quantities of DOM in their nutrition, unlike most other invertebrates. Here, we examine the cellular capacity for direct processing of DOM, and the fate of the processed matter, inside a dinoflagellate-hosting bioeroding sponge that is prominent on Indo-Pacific coral reefs. Integrating transmission electron microscopy with nanoscale secondary ion mass spectrometry, we track 15N- and 13C-enriched DOM over time at the individual cell level of an intact sponge holobiont. We show initial high enrichment in the filter-feeding cells of the sponge, providing visual evidence of their capacity to process DOM through pinocytosis without mediation of resident bacteria. Subsequent enrichment of the endosymbiotic dinoflagellates also suggests sharing of host nitrogenous wastes. Our results shed light on the physiological mechanism behind the ecologically important ability of sponges to cycle DOM via the recently described sponge loop.

The Mozambique Channel region in East Africa has diverse marine ecosystems and serves as a migratory corridor for economically important species. Local and foreign industrial fisheries operate in the Mozambique Channel, but regional small-scale fisheries are the crucially important fisheries that provide food security, livelihoods, and economic opportunities for rural coastal communities. This study reconstructed and investigated trends in the fishing effort and catch per unit effort (CPUE) of small-scale marine fisheries in four Exclusive Economic Zones (EEZ) that constitute the Mozambique Channel, i.e., Union of Comoros, Madagascar, Mayotte, and Mozambique, from 1950 to 2016. Effective fishing effort for small-scale fisheries in the form of fishing capacity in kWdays (i.e., kilowatt days) was derived using the number, length, motorization (engine power) by fishing vessels, as well as an approximate human-powered equivalent for shore-based fishers without vessels, as well as days of fishing per year. Effective small-scale fishing effort in the Mozambique Channel increased by nearly 60 times from just over 386,000 kWdays in 1950 to over 23 million kWdays in 2016. Correspondingly, the overall small-scale CPUE, based on previously and independently reconstructed catch data declined by 91% in the region as a whole, from just under 175 kg⋅kWday-1 in the early 1950s to just over 15 kg⋅kWday-1 in recent years. All four EEZs showed the strongest declines in the small-scale CPUE in the earlier decades, driven by motorization and growth in vessel numbers impacting effective fishing effort. Increased motorization combined with a substantial growth in overall vessel numbers were the drivers of the increasing fishing effort and decreasing CPUE, and clearly suggest that continuing to increase the fishing capacity of small-scale fisheries in the absence of effective and restrictive management actions may exacerbate overexploitation risk.

The productivity and sustainability of coastal, marine, and estuarine ecosystems are heavily reliant on the quality of coastal waters (JHA et al., 2013; JHA et al., 2015; DHEENAN et al., 2016). These locations are thought to have greater biodiversity than open ocean zones (GRAY, 1997). Among the biological components of soft bottom sediments, macrobenthic organisms are essential for ecosystem functioning (Pandey et al., 2022). They play a vital role in secondary production and nutrient exchange between the pelagic and benthic realms and therefore constitute essential elements of estuarine and coastal habitats (SNELGROVE, 1998) and are a reliable indicator for assessing the biotic integrity of the coastal ecosystem (RYU et al., 2011; Pandey et al., 2021). Due to their sedentary lifestyle, long life cycle, and differential response against the perturbation, they also serve as useful bio-indicator (GESTEIRA-GOMEZet al., 2003) for health monitoring and assessment of coastal ecosystems (GANESH et al., 2014) and evaluating the success of conservation efforts (WINBERGT et al., 2007). Identification of factors responsible for spatiotemporal patterns in macrofaunal assemblages is the primary goal amongst many marine benthic ecological studies (BOLAM et al., 2008; DUTERTRE et al., 2013; PANDEY and GANESH , 2019b). However, such pattern in the benthic community is often hard to predict due to the complex interplay between environmental parameters and biological interactions (ELLIS et al., 2006). The relationship between natural environmental factors and macrobenthos is reported to help delineate faunal distribution patterns, characterising benthic habitats, establish baseline knowledge, and enabling the detection of spatial and temporal variations (BOLAM et al., 2008; SHUMCHENIA and King, 2010; Dutertre et al., 2013). Numerous studies (Van Hoey et al., 2004; Hily et al., 2008; DUTERTRE et al., 2013; Pandey and Ganesh, 2019b) have identified sediment properties as a significan

Ethnobiological knowledge is an important part of people's capacity to manage, conserve, and improve the governance of mangrove ecosystems. This paper assesses the ethnobiological importance of mangroves to coastal communities adjacent to seven mangrove forests in Southern and North-western Sri Lanka. 197 households were interviewed, and respondents identified various mangrove ecosystem goods and services. Fruit juice produced from Sonneratia spp. and salads made with Acrostichum aureum L. young leaves constitutes valuable edible products in both regions. Rhizophora mucronata Lamk. and Lumnitzera racemosa Willd., were employed as alternative sources of fuel. Other uses of mangroves include wood for construction, chemical, and medicinal products. However, the usage extent was significantly higher in the Southern province (87.6%) compared to the North-western province (51%). Five indices were developed to understand the ethnobiological knowledge of respondents (Mangrove Use Index, Perception Index, Regulation Awareness Index, and Knowledge Index, Mangrove Dynamics Index). Except for the Mangrove Use Index, the rest of the indices were significantly different between the provinces. Communities with higher mangrove knowledge showed lesser usage. Respondents had negative attitudes towards the regulations that limit/did not allow the community to enter mangrove forests. Community participation, ethnobiological importance, and perspectives regarding how the community wants to manage mangrove forests should be taken into account to avoid conflicts in the future. Considering local perceptions and translating them into mangrove management regulations can be effective in guiding sustainable mangrove management in Sri Lanka as well as in other countries in the world.

Haslea ostrearia represents the model species of blue diatoms, a cluster of benthic marine species all belonging to the genus Haslea, noticeable for producing a blue pigment called marennine famous for its greening activity on the gills of bivalves but also for its potential in biotechnology. The exact distribution of H. ostrearia is unknown. It has been long considered a cosmopolitan diatom, but recent studies provided evidence for cryptic diversity and the existence of several other blue species, some of them inhabiting places where diatoms described as H. ostrearia had previously been observed. Recently, a marine diatom with blue tips was isolated into clonal culture from a plankton net sample from Kei Mouth on the Indian Ocean coast of South Africa. It was identified as H. ostrearia through a combination of LM/SEM microscopy and molecular analysis. This constitutes the first established record of this species from South Africa and the Indian Ocean and the second record for the southern hemisphere. Molecular barcoding clearly discriminated the South African strain from an Australian strain and cox1 based molecular phylogeny associated it instead with strains from the French Atlantic Coast, raising questions about the dispersal of this species. The complete mitochondrial and plastid genomes were compared to those of Haslea nusantara and Haslea silbo. Multigene phylogenies performed with all protein-coding genes of the plastome and the mitogenome associated H. ostrearia with H. silbo. In addition, complete sequences of circular plasmids were obtained and one of them showed an important conservation with a plasmid found in H. silbo.

India should not recognise International Maritime Boundary Line with Sri Lanka: Jayalalithaa .