The Geologic Remote Sensing Field Experiment (GRSFE)

Field measurements for the Geologic Remote Sensing Field Experiment (GRSFE) were concentrated in the Lunar Lake area of Nevada. The GRSFE data are meant to be used in a variety of investigations, including tests of multispectral radiative transfer models for scattering and emission from planetary surfaces in support of the Earth Observing System (EOS), Mars Observer, and Magellan Missions. Studies will also be pursued to establish the neotectonic and paleoclimatic history of the arid southwestern United States. The data will also be used to support Mars Rover Sample Return (MRSR) simulation studies

Spatial response of hard- and mixed-bottom benthic epifauna to organic enrichment from salmon aquaculture in northern Norway

Norwegian Atlantic salmon aquaculture is continuing to expand in northern regions dominated by hard- and mixed-bottom substrates. Such habitats contain rich benthic epifaunal communities, including sponges and other sessile invertebrates susceptible to the impacts of particulate material released from finfish farms. Here, conventional soft-sediment sampling techniques are unable to discern the impacts of farm waste, and new monitoring methods and indicator taxa must be identified. This study improves understanding of the impacts of particulate waste released from salmon farms on the density and structure of benthic epifaunal communities on mixed- and hard-bottom substrates. The diversity, density, and composition of epifaunal communities and visually conspicuous benthic infauna were recorded in towed camera transects along the enrichment gradient (~50-800 m) of 3 salmon farms in northern Norway. Elevated fluxes of particulate material in the vicinity of all farms significantly affected epifaunal community composition, as did the coverage of some key substrate types. The defecated mounds of lugworms and the seastar Asterias rubens were notably more abundant near the farms where fluxes were elevated. The sponges Polymastia spp. and Phakellia spp. and the soft coral Duva florida showed significant declines in density with increasing sedimentation and were principal taxa in communities at natural sedimentation levels. Results identify taxa with both positive and negative spatial associations to particulate waste released from finfish farms and the potential for the development of an epifauna indicator-based index for monitoring the environmental impacts of aquaculture in hard- and mixed-bottom dominated substrates.publishedVersio

Effect of substrate type and pellet age on the resuspension of Atlantic salmon faecal material

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Terrestrial fatty acids from feed oil in feed for farmed salmonids are transferred to the liver, gonads, and muscle of wild Atlantic cod (Gadus morhua)

Wild fish attracted to salmon farms feed on waste feed that presently contain high levels of fatty acids of terrestrial origin. This study examines whether mature Atlantic cod (Gadus morhua) caught at spawning grounds has eaten salmon waste feed. Cod were caught at four spawning grounds around Smøla (Norway), an area with multiple salmon farms, during the spawning season in 2018 (n = 327) and 2019 (n = 488). The fatty acid (FA) profile of their livers, gonads (ovary and testis), and muscles (2019) were determined. Multivariate k-mean cluster analysis of liver FA profiles revealed three main clusters, which could be allocated to trophic niches using known fatty acid trophic markers (FATMs). Of the sampled cod in 2018 and 2019, 13 % and 20 % respectively had high liver concentrations of terrestrial FATMs (18:1n-9, 18:2n-6, and 18:3n-3), indicating waste feed feeding. The remaining cod could be assigned to either the pelagic or benthic food chain. The cod identified as feeding on waste feed had large, fatty livers. The terrestrial FAs were also transferred to the muscle and gonad lipids. It is postulated that the latter may result in gametes with sub-optimal lipid composition, potentially impacting fitness, which warrants further investigation.Terrestrial fatty acids from feed oil in feed for farmed salmonids are transferred to the liver, gonads, and muscle of wild Atlantic cod (Gadus morhua)publishedVersio

Mine waste and acute warming induce energetic stress in the deep-sea sponge Geodia atlantica and coral Primnoa resedeaformis; results from a mesocosm study

There is the potential for climate change to interact with pollution in all of the Earth's oceans. In the fjords of Norway, mine tailings are released into fjords generating suspended sediment plumes that impact deep-sea ecosystems. These same deep-sea ecosystems are expected to undergo periodic warming as climate change increases the frequency of down-welling events in fjords. It remains unknown how a polluted deep-sea ecosystem would respond to down-welling because multiple stressors will often interact in unpredictable ways. Here, we exposed two deep-sea foundation species; the gorgonian coral Primnoa resedaeformis and the demosponge Geodia atlantica to suspended sediment (10 mg L−1) and acute warming (+5°C) in a factorial mesocosm experiment for 40 days. Physiology (respiration, nutrient flux) and cellular responses (lysosomal cell stability) were measured for both the coral and sponge. Exposure to elevated suspended sediment reduced metabolism, supressed silicate uptake and induced cellular instability of the sponge G. atlantica. However, combining sediment with warming caused G. atlantica to respire and excrete nitrogen at a greater rate. For the coral P. resedaeformis, suspended sediments reduced O:N ratios after 40 days, however, warming had a greater effect on P. resedaeformis physiology compared to sediment. Warming increased respiration, nitrogen excretion, and cellular instability which resulted in lower O:N ratios. We argue that suspended sediment and warming can act alone and also interact to cause significant harm to deep-sea biota, however responses are likely to be species-specific. Warming and pollution could interact in the deep-sea to cause mortality to the coral P. resedaeformis and to a lesser extent, the sponge G. atlantica. As foundation species, reducing the abundance of deep sea corals and sponges would likely impact the ecosystems they support.publishedVersio

Survival under conditions of variable food availability: Resource utilization and storage in the cold-water coral Lophelia pertusa

Cold‐water coral (CWC) reefs are hotspots of biodiversity and productivity in the deep sea, but their distribution is limited by the availability of food, which undergoes complex local and temporal variability. We studied the resource utilization, metabolism, and tissue storage of CWC Lophelia pertusa during an experimentally simulated 3‐day food pulse, of 13C15N‐enriched phytodetritus, followed by a 4‐week food deprivation. Oxygen consumption (0.145 μmol O2 [mmol organic carbon {OC}]−1 h−1), release of particulate organic matter (0.029 μmol particulate organic carbon [POC] [mmol OC]−1 h−1 and 0.005 μmol particulate organic nitrogen [mmol OC]−1 h−1), ammonium excretion (0.004 μmol NH4+ [mmol OC]−1 h−1), tissue C and N content, and fatty acid (FA) and amino acid composition did not change significantly during the experiment. Metabolization of the labeled phytodetritus, however, underwent distinct temporal dynamics. Initially, L. pertusa preferentially used phytodetritus‐derived C for respiration (2.2 ± 0.36 nmol C [mmol OC]−1 h−1) and mucus production (0.94 ± 0.52 nmol C [mmol OC]−1 h−1), but those tracer fluxes declined exponentially to <20% within 2 weeks after feeding and then remained stable, indicating that the remainder of the incorporated phytodetritus had entered a tissue pool with lower turnover. Analysis of 13C in individual FAs revealed a mismatch between the FAs incorporated from phytodetritus and the FA requirements of the coral. We suggest that feeding on other resources, such as lipid‐rich zooplankton, could fill this deficiency. A release of 10% of their total OC as respired C and POC during the 4‐week food deprivation underlines the importance of regular food pulses for CWC reefs.publishedVersio

Effect of suspended sediments on the pumping rates of three species of glass sponge in situ

The largest known glass sponge reefs in Canada are within the Hecate Strait and Queen Charlotte Sound Glass Sponge Reefs Marine Protected Area (HSQCS-MPA) in British Columbia. However, human activities outside the core MPA boundaries, such as trawling, can create plumes of suspended sediments capable of travelling large distances. We studied the response of 3 glass sponge species to changes in suspended sediment concentrations (SSCs) at 170 m depth inside the HSQCS-MPA. Two species reduced excurrent flow rate in response to natural and experimentally induced increases in suspended sediment. Background suspended sediment levels were low and showed little variation (2.71 ± 0.09 mg l-1, mean ± SD). Species varied in the threshold of SSCs that triggered arrests. Sediment concentrations of 2.8-6.4 mg l-1 caused arrests in Rhabdocalyptus dawsoni, while Heterochone calyx did not arrest until concentrations reached 5-10 mg l-1. Very small, but prolonged increases of suspended sediments (<1 mg l-1 for R. dawsoni and 3.2 mg l-1 for H. calyx) caused arrests of several hours in R. dawsoni and prolonged periods of reduced flow in H. calyx. No arrests were observed in Farrea occa, even after repeated exposures up to 57 mg l-1. A sediment transport model showed that sediment concentrations can remain high enough to affect sponge behaviour as far as 2.39 km from the source of the plume. The results highlight the importance of understanding the biology of different species for establishment of adequate boundaries in MPAs.publishedVersio

Habitat associations of juvenile Atlantic cod (Gadus morhua L.) and sympatric demersal fish communities within shallow inshore nursery grounds

Resolving the relationship between demersal fish and sublittoral biotic habitats and substrates is a key element in the protection of important nursery grounds for strengthening fish recruitment. In Norway, coastal Atlantic cod (Gadus morhua L.) is a commercially and culturally important demersal fish for Norwegian coastal communities, and in recent decades the stock has declined to such an extent that a plan to rebuild the stock to biologically safe limits has been implemented. Yet, little is known about the specific biotic and abiotic habitat associations of the early-life stages of coastal cod, which is important for the management and protection of the species. The same shallow, sublittoral zones are inhabited by juveniles and adults of other commercial demersal gadoids and wrasses. This study presents novel findings on associations between juvenile coastal cod and other demersal fish species with seafloor substrates and biological habitats, inferred from five years of extensive fyke net surveys. Newly settled 0-group cod were typically associated with eel grass and red algae biotic habitats on sand and shell sand substrates. However, there was an ontogenic habitat shift amongst one year old (1-group) individuals that became more ubiquitous with their biotic habitat or substrate type choices. The juvenile gadoids saithe (Pollachius virens) and pollack (Pollachius pollachius), were most associated with hard bottom dominated sites with saithe being more abundant at exposed sites, compared to pollack. Goldsinny wrasse (Ctenolabrus rupestris) and corkwing wrasse (Symphodus melops) appeared to favor sugar kelp forests and red algae. Overall, the study identifies the specific sublittoral biotic habitats and substrates important to different early life stages of juvenile coastal cod and other commercially important demersal fish, providing critical information needed for identifying candidate coastal habitats for protection.publishedVersio

Habitat associations of juvenile Atlantic cod (Gadus morhua L.) and sympatric demersal fish communities within shallow inshore nursery grounds

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Recycling pathways in cold-water coral reefs: Use of dissolved organic matter and bacteria by key suspension feeding taxa

Cold-water coral (CWC) reefs are one of the most diverse and productive ecosystems in the deep sea. Especially in periods of seasonally-reduced phytodetritus food supply, their high productivity may depend on the recycling of resources produced on the reef, such as dissolved organic matter (DOM) and bacteria. Here, we demonstrate that abundant suspension feeders Geodia barretti (high-microbial-abundance sponge), Mycale lingua (low-microbial-abundance sponge) and Acesta excavata (bivalve) are able to utilize 13C-enriched (diatom-derived) DOM and bacteria for tissue growth and respiration. While DOM was an important potential resource for all taxa, utilization of bacteria was higher for the sponges as compared to the bivalve, indicating a particle-size differentiation among the investigated suspension feeders. Interestingly, all taxa released 13C-enriched particulate organic carbon, which in turn may feed the detritus pathway on the reef. Especially A. excavata produced abundant (pseudo-)fecal droppings. A second stable-isotope tracer experiment revealed that detritivorous ophiuroids utilized these droppings. The high resource flexibility of dominant reef suspension feeders, and the efficient recycling of their waste products by the detritivore community, may provide important pathways to maintain the high productivity on cold-water coral reefs, especially in periods of low external food supply.publishedVersio