Highly managed and built environments such as zoos and aquaria provide a rich source of standardized environmental monitoring data over periods of years to decades. A fifty percent water change in an 11.4-million-liter indoor artificial sea water system housing three species of marine mammals was conducted over a two-month period. Using 16S rRNA gene sequencing, the microbial community structure of the system water and three host sites (feces, skin, and exhaled breath “chuff”) of whales housed in the system were characterized. Diversity measures confirmed massive disruption to the water community structure as an expected result of the water change. Host site-associated communities remained remarkably stable. Improved understanding of host microbial community dynamics in response to environmental system perturbations allows for sound management decisions toward optimizing conditions for resident animals.

The present work aimed to study whether a high sugar diet can alter immune responses and the gut microbiome in green iguanas. Thirty-six iguanas were split into four treatment groups using a 2×2 design. Iguanas received either a sugar-supplemented diet or a control diet, and either a lipopolysaccharide (LPS) injection or a phosphate-buffered saline (PBS) injection. Iguanas were given their respective diet treatment through the entire study (∼3 months) and received a primary immune challenge 1 and 2 months into the experiment. Blood samples and cloacal swabs were taken at various points in the experiment and used to measure changes in the immune system (bacterial killing ability, lysis and agglutination scores, LPS-specific IgY concentrations), and alterations in the gut microbiome. We found that a sugar diet reduces bacterial killing ability following an LPS challenge, and sugar and the immune challenge temporarily alters gut microbiome composition while reducing alpha diversity. Although sugar did not directly reduce lysis and agglutination following the immune challenge, the change in these scores over a 24-h period following an immune challenge was more drastic (it decreased) relative to the control diet group. Moreover, sugar increased constitutive agglutination outside of the immune challenges (i.e. pre-challenge levels). In this study, we provide evidence that a high sugar diet affects the immune system of green iguanas (in a disruptive manner) and alters the gut microbiome.

Nutritional programming (NP) is a concept in which early nutritional events alter the physiology of an animal and its response to different dietary regimes later in life. The objective of this study was to determine if NP via broodstock with dietary plant protein (PP) has any effect on the gut microbiome of the progeny fish and whether this modified gut microbiome leads to better utilization of PP diet. The experiment consisted of four different treatments as follows: (1) progeny that received FM diet obtained from fishmeal (FM)-fed broodstock (FMBS-FM, +control); (2) progeny that received PP diet obtained from FM-fed parents (FMBS-PP); (3) progeny that received PP diet obtained from “nutritionally programmed” parents (PPBS-PP; −control); and (4) progeny that received FM diet obtained from “nutritionally programmed” parents (PPBS-FM). Zebrafish was used as a model species. This study found that parental programming seems to have some positive effect on dietary PP utilization in progeny. However, the influence of NP with PP through broodstock on gut microbiota of the offspring fish was not detected.

As coral reefs face unprecedented declines driven by thermal stress and the breakdown of coral symbiosis (i.e., coral bleaching), restoration efforts increasingly rely on coral health and resilience rankings. However, seasonal plasticity in symbiosis and holobiont metabolism, along with the presence of cryptic species, can complicate data interpretation. Therefore, quantifying seasonal plasticity in coral physiology and incorporating genetic identification are essential for accurately interpreting and drawing conclusions from trait-based and fitness-based analyses. To test the effect of seasonal and site variation on physiological plasticity we sampled three ecologically dominant genera, Acropora , Pocillopora , and Porites across three lagoon sites (n=15 tagged colonies genus ⁻¹ site ⁻¹ ) on the north shore of Mo’orea French Polynesia in January, March, September, and December of 2020. We identified coral host and intracellular symbiotic Symbiodiniaceae to the highest taxonomic resolution possible and quantified 13 physiological variables within the holobiont. Genetic analyses identified A. pulchra along with cryptic lineages in Pocillopora ( P. meandrina, P. tuahiniensis ) and Porites ( P. evermanni, P. lobata/lutea ). A. pulchra was dominated by Durusdinium trenchii and also contained Symbiodinium microadriaticum. Symbiont communities differed between cryptic congeners, with P. meandrina hosting Cladocopium latusorum and P. tuahiniensis hosting Cladocopium pacificum , whereas P. evermanni and P. lobata/lutea both hosted Cladocopium (C15), but each with unique C15 profiles. Weedy taxa such as Acropora and Pocillopora displayed a cycle of symbiont boom and bust in response to seasonally variable light and temperature, likely contributing to the high stress sensitivity of these taxa. In contrast, despite seasonal environmental variability, Porites displayed greater symbiont stability, with temperature—rather than light—serving as the stronger explanatory variable of seasonal variation in host physiology. Increased host biomass under cooler conditions, which provides energy reserves, may serve as an important stabilizing factor in massive Porites well-documented stress resilience. Collectively, our data provide essential evidence of the need for integrative analyses considering baseline physiological states across seasons along with host and symbiont genetics, particularly in light of the plethora of climate change related stress test assays taking place throughout the year across coral taxa with cryptic lineages.

Closed recirculating aquatic systems (aquariums) offer a multitude of benefits including the ability to observe and research aquatic animals ex situ, and under controlled environmental conditions

As coral reefs face declines driven by thermal stress and the breakdown of coral symbiosis (i.e., coral bleaching), restoration efforts rely on coral health and resilience rankings. However, seasonal plasticity in symbiosis and metabolism and the presence of cryptic species complicates data interpretation. Quantifying seasonal plasticity in coral physiology and incorporating genetic identification are essential for interpreting and drawing conclusions from trait‐based and fitness‐based analyses. To test the effect of seasonal and site variation on physiology, we sampled three ecologically dominant genera, Acropora , Pocillopora , and Porites across three lagoon sites ( n = 15 tagged colonies genus ⁻¹ site ⁻¹ ) on the north shore of Moʻorea, French Polynesia in January, March, September, and December of 2020. We identified coral host and intracellular Symbiodiniaceae to the highest taxonomic resolution possible and quantified 13 physiological variables. Genetic analyses identified A. pulchra and cryptic lineages in Pocillopora ( P. meandrina , P. tuahiniensis ) and Porites ( P. evermanni , P. lobata/lutea ). Acropora pulchra hosted Durusdinium trenchii and Symbiodinium microadriaticum . Symbiont communities differed between cryptic congeners, with P. meandrina hosting Cladocopium latusorum and P. tuahiniensis hosting Cladocopium pacificum , whereas P. evermanni and P. lobata/lutea both hosted Cladocopium (C15), but each with unique C15 profiles. Acropora and Pocillopora displayed seasonal cycles of symbiont density and productivity (“boom and bust”) in association with light and temperature, a pattern that may contribute to the greater environmental sensitivity previously reported in these taxa. In contrast, Porites exhibited greater symbiont stability, with temperature—rather than light—showing stronger associations with host physiology. Increased host biomass under cooler conditions, which may provide greater energy reserves, could represent one mechanism contributing to the comparatively greater stress tolerance observed in massive Porites . Collectively, our findings highlight the importance of integrating baseline physiological measurements with host and symbiont genetics when interpreting coral responses across seasons.