A new sex-specific genetic marker (fshr 1834G>T) for flathead grey mullet, Mugil cephalus, in Queensland, Australia

In this study, genetic sex marker candidates from northern hemisphere Mugil cephalus were tested to see if they could be used to sex a population originating from south-east Queensland, Australia. As such, a region of the follicle stimulating hormone receptor (fshr) gene was sequenced but did not contain previously published single nucleotide polymorphisms (SNPs). However, further screening of the sequenced fshr region revealed a promising sex marker candidate for Queensland M. cephalus, fshr 1834 G>T, which was accurate in 100% of fish tested (excluding intersex fish, which had the female genotype). While all females tested were homozygous G/G, males presented as either G/T (common) or T/T (lower frequency). Subsequently, a real-time high-resolution melt was developed to facilitate rapid and accurate genotyping of M. cephalus based on the fshr 1834 G>T SNP. Initial results suggest that fshr 1834 G>T is a useful SNP that can reduce the need for more invasive sampling techniques such as gonadal biopsy, provide information relating to the sex of captive stock prior to gonadal maturation, and may prove useful in wild population surveys and stock assessment

Predatory bacteria in the haemolymph of the cultured spiny lobster Panulirus ornatus

Bdellovibrio and like organisms (BALOs) are Gram-negative obligate predators of other bacteria in a range of environments. The recent discovery of BALOs in the circulatory system of cultured spiny lobster P. ornatus warrants more investigation. We used a combination of co-culture agar and broth assays and transmission electron microscopy to show a Halobacteriovorax sp. strain Hbv preyed upon the model prey bacterium Vibrio sp. strain Vib. The haemolymph microbiome of juvenile P. ornatus was characterised following injection of phosphate buffered saline (control) or prey and/or predator bacteria for 3 d. The predator Hbv had no effect on survival compared to the control after 3 d. However, when compared to the prey only treatment group, lobsters injected with both prey and predator showed significantly lower abundance of genus Vibrio in the haemolymph bacterial community composition. This study indicates that predatory bacteria are not pathogenic and may assist in controlling microbial population growth in the haemolymph of lobsters

Airborne and Spaceborne Lidar Reveal Trends and Patterns of Functional Diversity in a Semi-Arid Ecosystem

Assessing functional diversity and its abiotic controls at continuous spatial scales are crucial to understanding changes in ecosystem processes and services. Semi-arid ecosystems cover large portions of the global terrestrial surface and provide carbon cycling, habitat, and biodiversity, among other important ecosystem processes and services. Yet, the spatial trends and patterns of functional diversity in semi-arid ecosystems and their abiotic controls are unclear. The objectives of this study are two-fold. We evaluated the spatial pattern of functional diversity as estimated from small footprint airborne lidar (ALS) with respect to abiotic controls and fire in a semi-arid ecosystem. Secondly, we used our results to understand the capabilities of large footprint spaceborne lidar (GEDI) for future applications to semi-arid ecosystems. Overall, our findings revealed that functional diversity in this ecosystem is mainly governed by elevation, soil, and water availability. In burned areas, the ALS data show a trend of functional recovery with time since fire. With 16 months of data (April 2019-August 2020), GEDI predicted functional traits showed a moderate correlation (r = 41–61%) with the ALS predicted traits except for the plant area index (PAI) (r = 11%) of low height vegetation (<5 m). We found that the number of GEDI footprints relative to the size of the fire-disturbed areas (=< 2 km2) limited the ability to estimate the full effects of fire disturbance. However, the consistency of diversity trends between ALS and GEDI across our study area demonstrates GEDI’s potential of capturing functional diversity in similar semi-arid ecosystems. The capability of spaceborne lidar to map trends and patterns of functional diversity in this semi-arid ecosystem demonstrates its exciting potential to identify critical biophysical and ecological shifts. Furthermore, opportunities to fuse GEDI with complementary spaceborne data such as ICESat-2 or the upcoming NASA-ISRO Synthetic Aperture Radar (NISAR), and fine scale airborne data will allow us to fill gaps across space and time. For the first time, we have the potential to monitor carbon cycle dynamics, habitats and biodiversity across the globe in semi-arid ecosystems at fine vertical scales

Boreal forest CO2 exchange and evapotranspiration predicted by nine ecosystem process models: Intermodel comparisons and relationships to field measurements

Nine ecosystem process models were used to predict CO2 and water vapor exchanges by a 150-year-old black spruce forest in central Canada during 1994–1996 to evaluate and improve the models. Three models had hourly time steps, five had daily time steps, and one had monthly time steps. Model input included site ecosystem characteristics and meteorology. Model predictions were compared to eddy covariance (EC) measurements of whole-ecosystem CO2exchange and evapotranspiration, to chamber measurements of nighttime moss-surface CO2release, and to ground-based estimates of annual gross primary production, net primary production, net ecosystem production (NEP), plant respiration, and decomposition. Model-model differences were apparent for all variables. Model-measurement agreement was good in some cases but poor in others. Modeled annual NEP ranged from −11 g C m−2 (weak CO2source) to 85 g C m−2 (moderate CO2 sink). The models generally predicted greater annual CO2sink activity than measured by EC, a discrepancy consistent with the fact that model parameterizations represented the more productive fraction of the EC tower “footprint.” At hourly to monthly timescales, predictions bracketed EC measurements so median predictions were similar to measurements, but there were quantitatively important model-measurement discrepancies found for all models at subannual timescales. For these models and input data, hourly time steps (and greater complexity) compared to daily time steps tended to improve model-measurement agreement for daily scale CO2 exchange and evapotranspiration (as judged by root-mean-squared error). Model time step and complexity played only small roles in monthly to annual predictions