Water temperature affects somatic growth, body condition and oxygen and carbon otolith isotopes of stout whiting (Sillago robusta).

Ocean warming will continue to affect the growth, body condition and geographic distributions of marine fishes and understanding these effects is an urgent challenge for fisheries research and management. Determining how temperature is recorded in fish otolith carbonate, provides an additional chronological tool to investigate thermal histories, preferences and patterns of movement throughout an individual's life history. The influence of three water temperature treatments (22°C, 25°C, and 28°C) on hatchery-reared juvenile stout whiting, Sillago robusta, was tested using a controlled outdoor mesocosm system. Fish were measured for change in length and weight, and body condition was determined using bioelectrical impedance analysis. Sagittal otoliths were analysed for stable oxygen (δ18Ootolith) and carbon (δ13Cotolith) isotopes via isotope ratio mass spectrometry. Whiting kept at 22°C were significantly smaller and had diminished body condition compared to fish in 25°C and 28°C, which did not significantly differ from each other. The δ18O otolith values of stout whiting demonstrated a negative temperature-dependent fractionation relationship which was similar in slope but had a different intercept to the relationships reported for inorganic aragonite and other marine fish species. The δ13C otolith values also showed a negative relationship with water temperature, and the calculated proportion of metabolic carbon M in otoliths differed between fish reared in the coolest (22°C) and warmest (28°C) temperature treatments. Overall, the results suggest that stout whiting may have reached an upper growth threshold between 25°C and 28°C, and that growth and body condition may be optimised during warmer seasons and toward the northerly regions of their distribution. Otolith oxygen thermometry shows promise as a natural tracer of thermal life history, and species-specific fractionation equations should be utilised when possible to prevent errors in temperature reconstructions of wild-caught fish.

Evaporative Cooling Does Not Prevent Vertical Dispersion of Effervescent Seawater Aerosol for Brightening Clouds.

Marine cloud brightening (MCB) is a potential intervention to mitigate the effects of climate change by increasing the reflectance of low-level maritime clouds, including those over the Great Barrier Reef. The technique involves dispersing a plume of submicrometer seawater droplets over the ocean, which evaporate, generating nanosized sea-salt aerosols (SSAs) that disperse through the atmosphere with some fraction incorporated into clouds. Droplet evaporation, which occurs in the immediate vicinity (meters to tens of meters) of the source, has been theorized to produce a negatively buoyant plume hindering the mixing of the sea-salt aerosol to cloud height and compromising the effectiveness of MCB. We characterized in situ for the first time the nearfield aerosol dispersion from a point source of atomized seawater produced using the effervescent technique. We observed consistent vertical mixing of the plume up to 150 ± 5 m height at 1 km downwind. The extent of vertical dispersion was influenced by wind velocity and atmospheric stability. We found no evidence that negative buoyancy due to the evaporation of the 0.068 kg/s water fraction significantly suppressed vertical mixing. Our results can be attributed to the small droplet sizes generated by the effervescent spray technology and associated low flow rates required to generate around 1014 droplets s-1. We estimate that, for a hypothetical implementation producing up to 1016 s-1 similarly sized SSAs, evaporative cooling is unlikely to significantly suppress the vertical dispersion of aerosol for MCB.

Disposable surgical masks affect the decomposition of Zostera muelleri.

The coronavirus pandemic has caused a surge in the use of both disposable and re-usable mask pollution globally. It is important to understand the potential impact this influx of novel pollution has on key ecological processes, such as detrital dynamics. We aimed to understand the impact mask pollution has on the decomposition of a common coastal seagrass, Zostera muelleri. Using an outdoor mesocosm system with heater chiller units and a gas mixer, we were able to test the impact of both re-usable single-ply homemade cotton masks and disposable surgical masks on samples of Z. muelleri detritus under different environmental conditions. We found that disposable masks, but not re-usable masks, significantly increased decomposition of Z. muelleri detritus. This may be due to the increased surface area available for detritivorous microorganism colonisation, driving further decomposition. This could have negative ramifications for seagrass communities and adjacent ecosystems.

Using multispectral drones to predict water quality in a subtropical estuary.

Drones are revolutionising earth system observations, and are increasingly used for high resolution monitoring of water quality. The objective of this research was to test whether drone-based multispectral imagery could predict important water quality parameters in an ICOLL (intermittently closed and opened lake or lagoon). Three water quality sampling campaigns were undertaken, measuring temperature, salinity, pH, dissolved oxygen (DO), chlorophyll (CHL), turbidity, total suspended sediments (TSS), coloured dissolved organic matter (CDOM), green algae, crytophyta, diatoms, bluegreen algae and total algal concentrations. DistilM statistical analyses were conducted to reveal the bands accounting for the most variation across all water quality data, then linear correlations between specific band/band ratios and individual water quality parameters were performed. DistilM analyses revealed the NIR band accounted for most variation in March, the Green band in April and the RE band in May, and showed that the most important contributors varied significantly among campaigns and variables. Significant linear correlations with R2 > 0.4 were obtained for eleven of the water quality parameters tested, with the strongest correlation obtained for CHL and the green band (R2 = 0.72). The relative importance of predictor bands and observed water quality parameters varied temporally. We conclude that drones with a multispectral sensor can produce useful 'snapshot' prediction maps for a range of water quality parameters, such as chlorophyll, bluegreen algae and dissolved oxygen. However, a single model was insufficient to reproduce the temporal variation of water parameters in dynamic estuarine systems.

The Relative Abundance and Occurrence of Sharks off Ocean Beaches of New South Wales, Australia.

There is still limited information about the diversity, distribution, and abundance of sharks in and around the surf zones of ocean beaches. We used long-term and large-scale drone surveying techniques to test hypotheses about the relative abundance and occurrence of sharks off ocean beaches of New South Wales, Australia. We quantified sharks in 36,384 drone flights across 42 ocean beaches from 2017 to 2021. Overall, there were 347 chondrichthyans recorded, comprising 281 (81.0%) sharks, with observations occurring in <1% of flights. Whaler sharks (Carcharhinus spp.) had the highest number of observations (n = 158) recorded. There were 34 individuals observed for both white sharks (Carcharodon carcharias) and critically endangered greynurse sharks (Carcharias taurus). Bull sharks (Carcharhinus leucas), leopard sharks (Stegostoma tigrinum) and hammerhead species (Sphyrna spp.) recorded 29, eight and three individuals, respectively. Generalised additive models were used to identify environmental drivers for detection probability of white, bull, greynurse, and whaler sharks. Distances to the nearest estuary, headland, and island, as well as water temperature and wave height, were significant predictors of shark occurrence; however, this varied among species. Overall, we provide valuable information for evidence-based species-specific conservation and management strategies for coastal sharks.

Increased shark bite survivability revealed by two centuries of Australian records.

The perceived and real threat of shark bites have significant direct health and indirect economic impacts. Here we assess the changing odds of surviving an unprovoked shark bite using 200 years of Australian records. Bite survivability rates for bull (Carcharhinus leucas), tiger (Galeocerdo cuvier) and white (Carcharodon carcharias) sharks were assessed relative to environmental and anthropogenic factors. Survivability of unprovoked bull, tiger and white shark bites were 62, 75 and 53% respectively. Bull shark survivability increased over time between 1807 and 2018. Survivability decreased for both tiger and white sharks when the person was doing an in water activity, such as swimming or diving. Not unsurprisingly, a watercraft for protection/floatation increased survivability to 92% from 30%, and 88% from 45%, for tiger and white sharks respectively. We speculate that survival may be related to time between injury and treatment, indicating the importance of rapid and appropriate medical care. Understanding the predictors of unprovoked bites, as well as survivability (year and water activity), may be useful for developing strategies that reduce the number of serious or fatal human-shark interactions without impacting sharks and other marine wildlife.

Desalination Discharge Influences the Composition of Reef Invertebrate and Fish Assemblages.

Large-scale desalination is used increasingly to address growing freshwater demands and climate uncertainty. Discharge of hypersaline brine from desalination operations has the potential to impact marine ecosystems. Here, we used a 7-year Multiple-Before-After-Control-Impact experiment to test the hypothesis that hypersaline discharge from reverse osmosis desalination alters temperate reef communities. Using replicated, video-based, timed searches at eight sites, we sampled fish and invertebrate assemblages before, during, and after the discharge of hypersaline brine. We found that the composition of fish assemblages was significantly altered out to 55 m while the composition of invertebrate assemblages was altered out to 125 m from the outlet during hypersaline discharge. Fish richness and functional diversity increased around the outlet, while the invertebrate assemblages were no less diverse than those on reference reefs. Differences in faunal assemblages between outlet and reference sites during discharging included changes in the frequency of occurrence of both common and rare reef biota. Overall, we found the influence of hypersaline discharge on temperate reef biota to be spatially localized, with the reefs around the outlet continuing to support rich and diverse faunal communities. In some cases, therefore, the marine environmental consequences of large-scale, well-designed, desalination operations may be appropriately balanced against the positive benefits of improved water security.

Spatial extent of desalination discharge impacts to habitat-forming species on temperate reefs.

Outlet infrastructure and hypersaline discharge from large-scale desalination operations have the potential to impact marine environments. Here, we present the results of a six-year M-BACI assessment of the impacts of desalination discharge outlet construction and hypersaline effluent on the cover of habitat-forming species on temperate reefs. The construction of the desalination outlet caused a decrease in the cover of Ecklonia radiata (kelp) and an increase in the cover of algal turfs up to 55 m from the outlet. Following the commencement of discharging of hypersaline brine, the impact to E. radiata and algal turfs persisted, but decreased in spatial extent to be less than 25 m from the outlet. Hypersaline discharge was also associated with a significant decline in the cover of sponges in outlet compared to reference sites. Overall, our results demonstrate that the water security benefits from large-scale desalination may sometimes be appropriately balanced against the associated ecological consequences.

Evaluating the effectiveness of drones for quantifying invasive upside-down jellyfish (Cassiopea sp.) in Lake Macquarie, Australia.

Upside-down jellyfish (Cassiopea sp.) are mostly sedentary, benthic jellyfish that have invaded estuarine ecosystems around the world. Monitoring the spread of this invasive jellyfish must contend with high spatial and temporal variability in abundance of individuals, especially around their invasion front. Here, we evaluated the utility of drones to survey invasive Cassiopea in a coastal lake on the east coast of Australia. To assess the efficacy of a drone-based methodology, we compared the densities and counts of Cassiopea from drone observations to conventional boat-based observations and evaluated cost and time efficiency of these methods. We showed that there was no significant difference in Cassiopea density measured by drones compared to boat-based methods along the same transects. However, abundance estimates of Cassiopea derived from scaling-up transect densities were over-inflated by 319% for drones and 178% for boats, compared to drone-based counts of the whole site. Although conventional boat-based survey techniques were cost-efficient in the short-term, we recommend doing whole-of-site counts using drones. This is because it provides a time-saving and precise technique for long-term monitoring of the spatio-temporally dynamic invasion front of Cassiopea in coastal lakes and other sheltered marine habitats with relatively clear water.

Persistence of seaweed forests in the anthropocene will depend on warming and marine heatwave profiles.

Marine heatwaves (MHWs), discrete periods of extreme warm water temperatures superimposed onto persistent ocean warming, have increased in frequency and significantly disrupted marine ecosystems. While field observations on the ecological consequences of MHWs are growing, a mechanistic understanding of their direct effects is rare. We conducted an outdoor tank experiment testing how different thermal stressor profiles impacted the ecophysiological performance of three dominant forest-forming seaweeds. Four thermal scenarios were tested: contemporary summer temperature (22°C), low persistent warming (24°C), a discrete MHW (22-27°C), and temperature variability followed by a MHW (22-24°C, 22-27°C). The physiological performance of seaweeds was strongly related to thermal profile and varied among species, with the highest temperature not always having the strongest effect. MHWs were highly detrimental for the fucoid Phyllospora comosa, whereas the laminarian kelp Ecklonia radiata showed sensitivity to extended thermal stress and demonstrated a cumulative temperature threshold. The fucoid Sargassum linearifolium showed resilience, albeit with signs of decline with bleached and degraded fronds, under all conditions, with stronger decline under stable control and warming conditions. The varying responses of these three co-occurring forest-forming seaweeds under different temperature scenarios suggests that the impact of ocean warming on near shore ecosystems may be complex and will depend on the specific thermal profile of rising water temperatures relative to the vulnerability of different species.

Assessment of acetylcholinesterase, catalase, and glutathione S-transferase as biomarkers for imidacloprid exposure in penaeid shrimp.

Shrimp aquaculture is a valuable source of quality seafood that can be impacted by exposure to insecticides, such as imidacloprid. Here, adult black tiger shrimp (Penaeus monodon) were used to evaluate the activity of acetylcholinesterase (AChE), catalase (CAT), and glutathione S-transferase (GST) in abdominal, head, gill, and hepatopancreas tissue as biomarkers for imidacloprid exposure. Adult P. monodon were continuously exposed to imidacloprid in water (5 µgL-1 and 30 µgL-1) or feed (12.5 µg g-1 and 75 µg g-1) for either 4 or 21 days. The imidacloprid concentration in shrimp tissues was determined using liquid chromatography-mass spectrometry after QuEChER extraction, and AChE, CAT, and GST activities were estimated by spectrophotometric assay. Imidacloprid exposure in shrimp elevated the activity of biomarkers, and the enzymatic activity was positively correlated to tissue imidacloprid accumulation, although the effects varied in a tissue-, dose- and time-dependent manner. AChE activity was correlated to imidacloprid concentration in the abdominal tissue of shrimp and was likely related to neural tissue distribution, while the activity of CAT and GST confirmed a generalised anti-oxidant stress response. AChE, CAT, and GST were valuable biomarkers for assessing shrimp response to imidacloprid exposure from dietary or water sources, and the abdominal tissue was the most reliable for exposure assessment. An elevated response in each of these biomarkers during routine monitoring could provide an early warning of shrimp stress, suggesting that investigating potential contamination by neonicotinoid pesticides would be worthwhile.

Marine heatwaves have minimal influence on the quality of adult Sydney rock oyster flesh.

Marine heatwaves (MHWs) are impacting marine biodiversity, including fisheries and aquaculture. However, it is largely unknown which species will be able to endure MHWs and at what price. Here, we applied elevated temperature (2 °C above ambient) and two different heatwave scenarios to adults of the economically important Sydney rock oyster (SRO, Saccostrea glomerata), and evaluated the impact on nutritional properties, gene expression profiles and immune health indicators. We found that elevated temperature (23 °C) and a variable heatwave (VHW) during winter caused some significant differences in the micronutrient and trace elements levels in oyster flesh. There was an increase of lead under VHW and a decrease in chromium, barium and aluminium under elevated temperature. Conversely, gene expression profiles and other physiological parameters, including flesh protein, fatty acid profiles and hemocyte numbers, were not affected by MHWs. These results indicate that adult SRO are reasonably resilient, and should continue to provide high-quality seafood, under near-future ocean warming and moderate heatwave scenarios.

Alkalinity of diverse water samples can be altered by mercury preservation and borosilicate vial storage.

We compared the effects of preservation and storage methods on total alkalinity (AT) of seawater, estuarine water, freshwater, and groundwater samples stored for 0-6 months. Water samples, untreated or treated with HgCl2, 0.45 µm filtration, or filtration plus HgCl2, were stored in polypropylene or borosilicate glass vials for 0, 1, or 6 months. Mean AT of samples treated with HgCl2 was reduced by as much as 49.1 µmol kg-1 (1.3%). Borosilicate glass elevated AT, possibly due to dissolving silicates. There was little change in AT of control and filtered samples stored in polypropylene, except for untreated groundwater (~ 4.1% reduction at 6 months). HgCl2 concentrations of 0.02-0.05% reduced the AT of fresh, estuarine, and ground water samples by as much as 35.5 µmol kg-1 after 1 month, but had little effect on the AT of seawater. Adding glucose as a carbon source for microbial growth resulted in no AT changes in 0.45 µm-filtered samples. We suggest water samples intended for AT analyses can be filtered to 0.45 µm, and stored in polypropylene vials at 4 °C for at least 6 months. Borosilicate glassware and HgCl2 can be avoided to prevent analytical uncertainties and reduce risks related to use of Hg2+.

Conservation genomics of a critically endangered brown seaweed.

Seaweeds provide valuable ecosystem services, but many are undergoing global decline due to climate and anthropogenic stressors. The brown macroalga, Nereia lophocladia (hereafter called Nereia), is among only a handful of seaweeds globally to be listed as critically endangered and is only described from two known locations, but there exists little knowledge about this species. Here, we combine field surveys to verify the distribution of Nereia, with cutting-edge genomics to determine genetic diversity and population structure, and inform ongoing conservation actions. We expand Nereia's known distribution from one to seven locations along a 70-km long coastal stretch in New South Wales but reveal small population sizes at some sites (as few as 8 individuals despite extensive searching). A total of 1,261 genome-wide SNPs were retained from 70 individuals after filtering, and 304 outlier loci under putative selection were detected by one of three methods. Populations showed low genetic diversity (mean expected heterozygosity HE  = 0.055 ± 0.014) and high levels of inbreeding within populations (mean FIS  = 0.721 ± 0.085), along with high genetic differentiation among sites (mean FST  = 0.276), which may increase susceptibility to future environmental change and decrease the species' ability to recover after loss. Given these findings, we recommend the consideration of both in situ and ex situ conservation measures for Nereia, as well as further research into the species' ecology and biology. Nereia remains of conservation concern and its listing as critically endangered is justified until further investigation elucidates the full distribution and adaptive capacity of the species.

Long-term thermal acclimation drives adaptive physiological adjustments of a marine gastropod to reduce sensitivity to climate change.

Ocean warming is predicted to challenge the persistence of a variety of marine organisms, especially when combined with ocean acidification. While temperature affects virtually all physiological processes, the extent to which thermal history mediates the adaptive capacity of marine organisms to climate change has been largely overlooked. Using populations of a marine gastropod (Turbo undulatus) with different thermal histories (cool vs. warm), we compared their physiological adjustments following exposure (8-week) to ocean acidification and warming. Compared to cool-acclimated counterparts, we found that warm-acclimated individuals had a higher thermal threshold (i.e. increased CTmax by 2 °C), which was unaffected by the exposure to ocean acidification and warming. Thermal history also strongly mediated physiological effects, where warm-acclimated individuals adjusted to warming by conserving energy, suggested by lower respiration and ingestion rates, energy budget (i.e. scope for growth) and O:N ratio. After exposure to warming, warm-acclimated individuals had higher metabolic rates and greater energy budget due to boosted ingestion rates, but such compensatory feeding disappeared when combined with ocean acidification. Overall, we suggest that thermal history can be a critical mediator of physiological performance under future climatic conditions. Given the relatively gradual rate of global warming, marine organisms may be better able to adaptively adjust their physiology to future climate than what short-term experiments currently convey.

Acute toxicity, accumulation and sublethal effects of four neonicotinoids on juvenile Black Tiger Shrimp (Penaeus monodon).

Neonicotinoid pesticides have been detected in aquatic habitats, and exposure may impact the health of aquatic organisms such as commercially-important crustaceans. Black Tiger Shrimp (Penaeus monodon) is a broadly distributed and high-value shrimp species that rely on estuaries for early life stages. Differences in the acute toxicity and accumulation of different neonicotinoids in tissues of commercial crustaceans have not been widely investigated. This study compared acute toxicity, uptake, and depuration of four neonicotinoids; thiamethoxam, clothianidin, acetamiprid, and imidacloprid, on juvenile P. monodon and their effects on enzyme biomarkers. Acute toxicity (48-h LC50) was determined as 190 µg L-1 (clothianidin), 390 µg L-1 (thiamethoxam), 408 µg L-1 (imidacloprid), and >500 µg L-1(acetamiprid). To assess uptake and elimination, shrimp were exposed to a fixed 5 µg L-1 water concentration for eight days (uptake) or four days of exposure followed by four days of depuration (elimination). Neonicotinoid water and tissue concentrations were measured by liquid chromatography-mass spectrometry following solid-phase extraction and QuEChER extraction respectively. The lower toxicity associated with acetamiprid could be associated with lower accumulation in the tissue, with concentrations remaining below 0.01 µg g-1. The activity of acetylcholinesterase, catalase and glutathione S-transferase in abdominal tissues was determined by spectrophotometric assay, with significant sublethal effects detected for all four neonicotinoids. Depuration reduced the tissue concentration of the active ingredient and reduced the activity of oxidative stress enzymes. Given acetamiprid showed no acute toxicity and reduced impact on the enzymatic activity of P. monodon, it may be an appropriate alternative to other neonicotinoids in shrimp producing areas.

Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciences.

Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental datasets, that these types of designs usually give less biased estimates than simpler observational designs. We propose a model-based approach to combine study estimates that may suffer from different levels of study design bias, discuss the implications for evidence synthesis, and how to facilitate the use of more credible study designs.

Anemonefish facilitate bleaching recovery in a host sea anemone.

Ocean warming is causing the symbioses between cnidarians and their algal symbionts to breakdown more frequently, resulting in bleaching. For sea anemones, nutritional benefits derived from hosting anemonefishes increase their algal symbiont density. The sea anemone-anemonefish relationship could, therefore, facilitate bleaching recovery. To test this, bleached and unbleached sea anemones, both with and without anemonefish, were monitored in the laboratory. At the start of our experiment, algal symbiont density and colour score were lower in the bleached than unbleached sea anemones, whereas total chlorophyll remained similar. After 106 days, bleached sea anemones with anemonefish had an algal symbiont density and colour score equal to the controls (unbleached sea anemones and without anemonefish), indicating recovery had occurred. Furthermore, total chlorophyll was 66% higher in the bleached sea anemones with anemonefish than the controls. In contrast, recovery did not occur for the bleached sea anemones without anemonefish as they had 78% fewer algal symbionts than the controls, and colour score remained lower. Unbleached sea anemones with anemonefish also showed positive changes in algal symbiont density and total chlorophyll, which increased by 103% and 264%, respectively. Consequently, anemonefishes give their host sea anemones a distinct ecological advantage by enhancing resilience to bleaching, highlighting the benefits of symbioses in a changing climate.

Climate drives the geography of marine consumption by changing predator communities.

The global distribution of primary production and consumption by humans (fisheries) is well-documented, but we have no map linking the central ecological process of consumption within food webs to temperature and other ecological drivers. Using standardized assays that span 105° of latitude on four continents, we show that rates of bait consumption by generalist predators in shallow marine ecosystems are tightly linked to both temperature and the composition of consumer assemblages. Unexpectedly, rates of consumption peaked at midlatitudes (25 to 35°) in both Northern and Southern Hemispheres across both seagrass and unvegetated sediment habitats. This pattern contrasts with terrestrial systems, where biotic interactions reportedly weaken away from the equator, but it parallels an emerging pattern of a subtropical peak in marine biodiversity. The higher consumption at midlatitudes was closely related to the type of consumers present, which explained rates of consumption better than consumer density, biomass, species diversity, or habitat. Indeed, the apparent effect of temperature on consumption was mostly driven by temperature-associated turnover in consumer community composition. Our findings reinforce the key influence of climate warming on altered species composition and highlight its implications for the functioning of Earth's ecosystems.

The influence of plastic pollution and ocean change on detrital decomposition.

Plastic pollution and ocean change have mostly been assessed separately, missing potential interactions that either enhance or reduce future impacts on ecosystem processes. Here, we used manipulative experiments with outdoor mesocosms to test hypotheses about the interactive effects of plastic pollution, ocean warming and acidification on macrophyte detrital decomposition. These experiments focused on detritus from kelp, Ecklonia radiata, and eelgrass, Zostera muelleri, and included crossed treatments of (i) no, low and high plastic pollution, (ii) current/future ocean temperatures, and (iii) ambient/future ocean partial pressure of carbon dioxide (pCO2). High levels of plastic pollution significantly reduced the decomposition rate of kelp and eelgrass by approximately 27% and 36% in comparison to controls respectively. Plastic pollution also significantly slowed the nitrogen liberation from seagrass and kelp detritus. Higher seawater temperatures significantly increased the decomposition rate of kelp and eelgrass by 12% and 5% over current conditions, respectively. Higher seawater temperatures were also found to reduce the nitrogen liberation in eelgrass. In contrast, ocean acidification did not significantly influence the rate of macrophyte decomposition or nutrient liberation. Overall, our results show how detrital processes might respond to increasing plastic pollution and ocean temperatures, which has implications for detrital-driven secondary productivity, nutrient dynamics and carbon cycling.