Katharina Fabricius

• PhD
• Senior Principal Resaerch Scientist at Australian Institute of Marine Science

The world's coral reefs are being degraded, and the need to reduce local pressures to offset the effects of increasing global pressures is now widely recognized. This study investigates the spatial and temporal dynamics of coral cover, identifies the main drivers of coral mortality, and quantifies the rates of potential recovery of the Great Barrie...

The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densitie...

Coral reefs are highly sensitive to ocean acidification due to rising atmospheric CO2 concentrations. We present 10 years of data (2009–2019) on the long-term trends and sources of variation in the carbon chemistry from two fixed stations in the Australian Great Barrier Reef. Data from the subtropical mid-shelf GBRWIS comprised 3-h instrument recor...

NOTE: THIS REVISION NOW CONTAINS AN OVERVIEW OF THE FAMILIES, WHICH WAS MISSING IN THE PREVIOUS VERSION (PAGES 47-65). This is a pdf, version 2, of our book "Fabricius KE & Alderslade P (2001) Soft Corals and Sea Fans: A comprehensive guide to the tropical shallow water genera of the central-west Pacific, the Indian Ocean and the Red Sea. Australi...

Coral reefs worldwide are experiencing frequent disturbances, rendering coral recruitment critical for population recovery. This large-scale study identifies environmental, spatial, and biotic drivers of coral recruit densities at 141 stations stratified across seven regions and three depths (1, 5, and 15 m depths) with contrasting environmental co...

Understanding how bleaching severity varies across space and among and within taxa helps predict changes in community composition due to climate change and informs conservation efforts. Photogrammetry offers a non‐invasive and time effective method for quantifying attributes of thousands of coral colonies across large, environmentally diverse reef...

Trait-based approaches are revolutionizing our understanding of high-diversity ecosystems by providing insights into the principles underlying key ecological processes, such as community assembly, species distribution, resilience, and the relationship between biodiversity and ecosystem functioning. In 2016, the Coral Trait Database advanced coral r...

Supplementary Tables and Figures associated with the manuscript: The Octocoral Trait Database: a global database of trait information for octocoral species

Underwater photogrammetry is routinely used to monitor large areas of complex and heterogeneous ecosystems, such as coral reefs. However, deriving data on benthic components (i.e. sand, rubble, coral and algae) from photogrammetry products has remained challenging due to the highly time‐consuming process of manual data extraction. We developed a ma...

Recent discussions have raised concerns about the long-term effectiveness of coral reef restoration efforts, questioning whether current interventions can effectively address the ongoing loss of reef ecosystems. However, details matter and vary greatly with respect to scale, social context and benefits, and diverse approaches are needed to maintain...

Aim Identifying the maximum coral cover that a coral community can sustain (i.e., its ‘upper limit’) is important for predicting community dynamics and improving management strategies. Here, we quantify the relationship between estimated upper limits and key environmental factors on coral reefs: hard substrate availability, temperature and water cl...

The 2022 Scientific Consensus Statement brings together the latest scientific evidence to understand how land-based activities can influence water quality in the Great Barrier Reef, and how these influences can be managed to improve water quality outcomes for the Great Barrier Reef. This document, the ‘2022 Scientific Consensus Statement Summary’,...

The 2022 Scientific Consensus Statement on land-based impacts to Great Barrier Reef water quality and ecosystem condition brings together the latest scientific evidence to understand how land-based activities can influence water quality in the Great Barrier Reef, and how these influences can be managed.

A habitat’s structural complexity is a key determinant of the recruitment and composition of associated communities. While the influence of the physical structure of corals on coral reef fish recruitment is well studied, the significance of other benthic components, like macroalgae, remains unclear. We used experimental patches of the canopy-formin...

Background Microbes play vital roles across coral reefs both in the environment and inside and upon macrobes (holobionts), where they support critical functions such as nutrition and immune system modulation. These roles highlight the potential ecosystem-level importance of microbes, yet most knowledge of microbial functions on reefs is derived fro...

Nearly a billion people depend on tropical seascapes. The need to ensure sustainable use of these vital areas is recognised, as one of 17 policy commitments made by world leaders, in Sustainable Development Goal (SDG) 14 (‘Life below Water’) of the United Nations. SDG 14 seeks to secure marine sustainability by 2030. In a time of increasing social-...

Macroalgae are an important component of coral reef ecosystems. We identified spatial patterns, environmental drivers and long-term trends of total cover of upright fleshy and calcareous coral reef inhabiting macroalgae in the Great Barrier Reef. The spatial study comprised of one-off surveys of 1257 sites (latitude 11–24°S, coastal to offshore, 0–...

As the human population and demand for food grow¹, the ocean will be called on to provide increasing amounts of seafood. Although fisheries reforms and advances in offshore aquaculture (hereafter ‘mariculture’) could increase production², the true future of seafood depends on human responses to climate change³. Here we investigated whether coordina...

Reef-building corals are subject to multi-day periods of reduced light and progressive ocean acidification. We experimentally assessed how adult and early post-settlement Acropora tenuis and A. hyacinthus corals responded to contrasting daily light integrals (DLI) and to multi-day variability in DLI, and whether contrasting DLIs altered the effects...

Small cryptic invertebrates (the cryptofauna) are extremely abundant, ecologically important, and species rich on coral reefs. Ongoing ocean acidification is likely to have both direct effects on the biology of these organisms, as well as indirect effects through cascading impacts on their habitats and trophic relationships. Naturally acidified hab...

Abstract. Crown-of-thorns sea stars (Acanthaster sp.) are among the most studied coral reef organisms, owing to their propensity to undergo major population irruptions, which contribute to significant coral loss and reef degradation throughout the Indo-Pacific. However, there are still important knowledge gaps pertaining to the biology, ecology, an...

This study investigates the effects of long-term exposure to OA on skeletal parameters of four tropical zooxanthellate corals naturally living at CO2 seeps and adjacent control sites from two locations (Dobu and Upa Upasina) in the Papua New Guinea underwater volcanic vent system. The seeps are characterized by seawater pH values ranging from 8.0 t...

Good water quality is essential to the health of marine ecosystems, yet current metrics used to track water quality in the Great Barrier Reef are not strongly tied to ecological outcomes. There is a need for a better water quality index (WQI). Benthic irradiance, the amount of light reaching the seafloor, is critical for coral and seagrass health a...

Assisting the natural recovery of coral reefs through local management actions is needed in response to increasing ecosystem disturbances in the Anthropocene. There is growing evidence that commonly used resilience-based passive management approaches may not be sufficient to maintain coral reef key functions. We synthesize and discuss advances in c...

It is hypothesized that spatio-temporal variability in larval supply is caused by multiple biophysical drivers which correlate with the occurrence of recruitment pulses, influencing the recovery potential of coral reefs following large-scale disturbances. Here, we used a larval dispersal model to explore coral larvae dispersal patterns under variab...

Coral bleaching, cyclones, outbreaks of crown-of-thorns seastar, and reduced water quality (WQ) threaten the health and resilience of coral reefs. The cumulative impacts from multiple acute and chronic stressors on "reef State" (i.e., total coral cover) and "reef Performance" (i.e., the deviation from expected rate of total coral cover increase) ha...

The responses of corals and other marine calcifying organisms to ocean acidification (OA) are variable and span from no effect to severe responses. Here we investigated the effect of long-term exposure to OA on skeletal parameters of four tropical zooxanthellate corals living at two CO 2 vents in Papua New Guinea, namely in Dobu and Upa Upasina. Th...

Most laboratory experiments examining the effect of ocean acidification on marine organisms use stable pH/pCO2 treatments based on average projections for the open ocean. However, pH/pCO2 levels vary spatially and temporally in marine environments, and this variation can affect organism responses to pH/pCO2. On coral reefs, diel pH/pCO2 variability...

Corrections for equations in our recently published paper [Opt. Express 27, A1350 (2019)] are presented.

Scleractinian corals often reproduce in synchronized spawning events to maximize gamete fertilization and coral larval production. The extent of spawning synchrony and its timing vary among coral taxa and among biogeographic regions. Information is, however, limited, especially for equatorial reefs, hindering the identification of environmental cue...

Following disturbances, corals recolonize space through the process of recruitment consisting of the three phases of propagule supply, settlement, and post-settlement survival. Yet, each phase is influenced by biophysical factors, leading to recruitment success variability through space. To resolve the relative contributions of biophysical factors...

Seawater acidification from increasing CO2 is often enhanced in coastal waters due to elevated nutrients and sedimentation. Our understanding of the effects of ocean and coastal acidification on present‐day ecosystems is limited. Here we use data from three independent large‐scale reef monitoring programs to assess coral reef responses associated w...

It is hypothesized that spatio-temporal variability in larval supply is caused by multiple biophysical drivers which correlate with the occurrence of recruitment pulses, influencing the recovery potential of coral reefs following large-scale disturbances. Here, we used a larval dispersal model to explore coral larvae dispersal patterns under variab...

In situ effects of ocean acidification are increasingly studied at submarine CO2 vents. Here we present a preliminary investigation into the water chemistry and biology of cool temperate CO2 vents near Whakaari–White Island, New Zealand. Water samples were collected inside three vent shafts, within vents at a distance of 2 m from the shaft and at c...

We demonstrate a simple, spectrally resolved ocean color remote sensing model to estimate benthic photosynthetically active radiation (bPAR) for the waters of the Great Barrier Reef (GBR), Australia. For coastal marine environments and coral reefs, the underwater light field is critical to ecosystem health, but data on bPAR rarely exist at ecologic...

A combination of qualitative and semi-quantitative assessments was used to estimate the relative risk of water quality constituents to Great Barrier Reef ecosystem health from major sources in the Great Barrier Reef catchments, focusing on agricultural land uses. In this assessment, the risk was defined simply as the area of coral reefs and seagras...

Australia has one of the largest marine jurisdictions on Earth, and it has been estimated that marine industry will contribute ~$100 billion per annum to the national economy by 2025. However, in recent decades there has been a decline in student uptake in the fields of science, technology, engineering, and mathematics (STEM). Marine science can pl...

Final technical report of NESP project 2.3.1 (Benthic light as an ecologically validated water quality indicator). Describes experimental results to determine responses of coral species to variable light conditions; the development of a satellite algorithm to estimate benthic light (bPAR) in the Great Barrier Reef from MODIS ocean colour data; and...

Marine species and ecosystems are exposed to a wide range of environmental change – both detrimental (threats) and beneficial – due to human activities. Some of the changes are global, whereas others are regional or local. It is important to distinguish the scale of each threat as the solutions will differ. For example, the mitigation of a global p...

Coastal water quality and light attenuation can detrimentally affect coral health. This study investigated the effects of light limitation and reduced water quality on the physiological performance of the coral Acropora tenuis. Branches of individual colonies were collected in 2 m water depth at six inshore reefs at increasing distances from major...

Understanding processes that drive community recovery are needed to predict ecosystem trajectories and manage for impacts under increasing global threats. Yet, the quantification of community recovery in coral reefs has been challenging owing to a paucity of long-term ecological data and high frequency of disturbances. Here we investigate community...

Pontellid copepods are archetypical representatives of the neuston—the highly specialized community living in the top 5–10 cm of the ocean surface. Their deep blue pigmentation and large eyes are unique adaptations to surface irradiation and carnivory, but poor prerequisites for survival in the transparent waters beneath the sea surface. Here, we r...

Fatty acids (FA) play a vital role in coral physiology, metabolism and stress resistance. Optimal health requires a balance of fatty acids, and more specifically essential polyunsaturated fatty acids (PUFA), for efficient biochemical and physiological functioning. Therefore, it is necessary to fully assess and evaluate the viability of FA as biomar...

The Great Barrier Reef (GBR) is the largest contiguous coral reef system in the world. Carbonate chemistry studies and flux quantification within the GBR have largely focused on reef calcification and dissolution, with relatively little work on shelf-scale CO2 dynamics. In this manuscript, we describe the shelf-scale seasonal variability in inorgan...

Ocean acidification (OA) as a result of increased anthropogenic CO2 input into the atmosphere carries consequences for all ocean life. Low pH can cause a shift in coral-associated microbial communities of pCO2-sensitive corals, however, it remains unknown whether the microbial community is also influenced in corals known to be more tolerant to high...

Studies documenting the effects of land-derived suspended particulate matter (SPM, i.e., particulate organic matter and mineral sediment) on marine ecosystems are typically disconnected from terrestrial studies that determine their origin, transport and fate. This study reviews sources, transport, transformations, fate and effects of SPM along the...

Phototrophic sessile organisms, such as reef corals, adjust their photosynthetic apparatus to optimize the balance of light capture versus protection in response to variable light availability (photoacclimation). In shallow marine environments, daily light integrals (DLI) can vary several-fold in response to water clarity and clouds. This laborator...

Coral reef ecosystems are under increasing pressure by multiple stressors that degrade reef condition and function. Although improved management systems have yielded benefits in many regions, broad‐scale declines continue and additional practical and effective solutions for reef conservation and management are urgently needed. Ecological interventi...

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis,...

Percent cover of the sum of non-calcifying (a) and calcifying (b) invertebrates on the lower tile sides at Upa-Upasina (white points) and Dobu (grey points) in relation to median pHT. Left and right hand panels represent the five and 13 month census periods, respectively. The black lines represent the modelled means, while the grey lines are confid...

Percent cover of the non-calcifying algal groups responsible for the increases seen along the pH gradient at Upa-Upasina (white points) and Dobu (grey points): green filamentous algae on the upper tile sides (a) and cyanobacteria (b) and macroalgae (c) on the lower tile sides. Left and right hand panels represent the five and 13 month census period...

Mean carbon chemistry parameters from the settlement tile metabolism incubation water at the two sites (Control: C and Seep: S) and two reefs Upa-Upasina (Upa) and Dobu (Dob). Standard errors are shown in brackets. N = 2 and 4 per control and seep site. (DOCX)

Changes in community rates of gross photosynthesis, respiration, net daily production, and dark calcification with carbonate system parameters (median in situ value for each tile, numerical variable) and separately with the cover of the main OTUs (benthos) also included. Median pH was used as predictor in oxygen production and consumption models (F...

The operational taxonomic units (OTUs) and their description for the benthic groups classified on the settlement tiles. Some OTUs were further classified into more general grouping for analysis (Group). (DOCX)

Generalised linear model results of pH, Reef (Dobu vs Upa-Upasina) and Time (five vs 13 months deployment) effects on the cover or abundance of operational taxonomic units (OTUs). Up and low refer to the upper and lower sides of the tiles, respectively. Non-significant terms removed from final models. Caption as in Table 1. *indicates taxa which we...

This is a response to the published Viewpoint by Larcombe and Ridd (2018). We agree with Larcombe and Ridd (2018) that scientific merit goes hand in hand with rigorous quality control. However, we are responding here to several points raised by Larcombe and Ridd (2018) which in our view were misrepresented. We describe the formal and effective scie...

Marine life is controlled by multiple physical and chemical drivers and by diverse ecological processes. Many of these oceanic properties are being altered by climate change and other anthropogenic pressures. Hence identifying the influences of multi-faceted ocean change, from local to global scales, is a complex task. To guide policy-making and ma...

Quantifying the amount of carbon dioxide (CO2) in seawater is an essential component of ocean acidification research; however, equipment for measuring CO2 directly can be costly and involve complex, bulky apparatus. Consequently, other parameters of the carbonate system, such as pH and total alkalinity (AT), are often measured and used to calculate...

CO2 measurements recorded by the portable CO2 equilibrator over time from the start of a test period until equilibrium is reached (boxed area). Stabilisation time was 1 hour. This time period is a conservative estimate since equilibration time is shorter if the pCO2 difference between two samples is less. (PDF)

The future of coral reefs under increasing CO2 depends on their capacity to recover from disturbances. To predict the recovery potential of coral communities that are fully acclimatized to elevated CO2, we compared the relative success of coral recruitment and later life stages at two volcanic CO2 seeps and adjacent control sites in Papua New Guine...

We developed a novel integrated technology for diver-operated surveying of shallow marine ecosystems. The HyperDiver system captures rich multifaceted data in each transect: hyperspectral and color imagery, topographic profiles, incident irradiance and water chemistry at a rate of 15–30 m2 per minute. From surveys in a coral reef following standard...

CO2 seeps in coral reefs were used as natural laboratories to study the impacts of ocean acidification on the pontellid copepod, Labidocera spp. Pontellid abundances were reduced by ∼70% under high-CO2 conditions. Biological parameters and substratum preferences of the copepods were explored to determine the underlying causes of such reduced abunda...

This study explores how plasticity in biochemical attributes, used as indicators of health and condition, enables the coral Acropora tenuis to respond to differing water quality regimes in inshore regions of the Great Barrier Reef. Health attributes were monitored along a strong and weak water quality gradient, each with three reefs at increasing d...

Coral reproduction is vulnerable to both declining water quality and warming temperatures, with simultaneous exposures likely compounding the negative impact of each stressor. We investigated how early life processes of the coral Acropora tenuis respond to increasing levels of suspended sediments in combination with temperature or organic nutrients...

Organisms that accumulate calcium carbonate structures are particularly vulnerable to ocean warming (OW) and ocean acidification (OA), potentially reducing the socioeconomic benefits of ecosystems reliant on these taxa. Since rising atmospheric CO2 is responsible for global warming and increasing ocean acidity, to correctly predict how OW and OA wi...

Bacterial biofilms provide cues for the settlement of marine invertebrates such as coral larvae, and are therefore important for the resilience and recovery of coral reefs. This study aimed to better understand how ocean acidification may affect the community composition and diversity of bacterial biofilms on surfaces under naturally reduced pH con...

The effects of ocean acidification (OA) on the structure and complexity of coastal marine biogenic habitat have been broadly overlooked. Here we explore how declining pH and carbonate saturation may aaect the structural complexity of four major biogenic habitats. Our analyses predict that indirect eeects driven by OA on habitat-forming organisms co...

Ocean acidification (OA) impacts the physiology of diverse marine taxa;among themcorals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO2) ecosystems. For the first time, we independently quantified the response of multiple functional...

Loads of suspended sediment, nutrients and pesticides discharged to the Great Barrier Reef (GBR) have increased greatly due to agricultural and urban development of the GBR catchment. As a result, in association with climate change impacts, the ecosystems of the GBR have degraded greatly in recent decades, and the decline in ecosystem health contin...

Inshore coral reefs are experiencing the combined pressures of excess nutrient availability associated with coastal activities and warming seawater temperatures. Both pressures are known to have detrimental effects on the early life history stages of hard corals, but studies of their combined effects on early demographic stages are lacking. We cond...

The in situ effects of ocean acidification on zooplankton communities remain largely unexplored. Using natural volcanic CO 2 seep sites around tropical coral communities, we show a threefold reduction in the biomass of demersal zooplankton in high-CO 2 sites compared with sites with ambient CO 2. Differences were consistent across two reefs and thr...