Publications

Life has been evolving in the oceans much longer than it has on land, resulting in highly diverse ocean organisms—particularly microbes like bacteria and archaea. Ocean microbes perform crucial functions that influence the health of the ocean and ultimately impact Earth’s climate. To understand the diversity and functions of marine organisms, scientists have used a powerful technique called metagenomics to study the DNA of all the organisms present in an ocean-water sample at once. In our research, we combined results from multiple ocean metagenomic studies, taken from various locations and depth zones across the world’s oceans, to produce a global ocean genome composed of 317.5 million groups of similar genes—approximately half of which could be categorized by type of organism and function. This unprecedented amount of data has much to teach us about varied ocean habitats and can help scientists answer many questions about ocean organisms and their functions.

Abstract Aim Scientific debate regarding the future trends, and subsequent ecological, biogeochemical and societal impacts, of gelatinous zooplankton ( GZ ) in a changing ocean is hampered by lack of a global baseline and an understanding of the causes of biogeographic patterns. We address this by using a new global database of GZ records to test hypotheses relating to environmental drivers of biogeographic variation in the multidecadal baseline of epipelagic GZ biomass in the world's oceans. Location Global oceans. Methods Over 476,000 global GZ data and metadata items were assembled from a variety of published and unpublished sources. From this, a total of 91,765 quantitative abundance data items from 1934 to 2011 were converted to carbon biomass using published biometric equations and species‐specific average sizes. Total GZ , Cnidaria, Ctenophora and Chordata (Thaliacea) biomass was mapped into 5° grid cells and environmental drivers of geographic variation were tested using spatial linear models. Results We present JeDI (the J ellyfish D atabase I nitiative), a publically accessible database available at http://jedi.nceas.ucsb.edu . We show that: (1) GZ are present throughout the world's oceans; (2) the global geometric mean and standard deviation of total gelatinous biomass is 0.53 ± 16.16 mg C m −3 , corresponding to a global biomass of 38.3 Tg C in the mixed layer of the ocean; (3) biomass of all gelatinous phyla is greatest in the subtropical and boreal Northern Hemisphere; and (4) within the North Atlantic, dissolved oxygen, apparent oxygen utilization and sea surface temperature are the principal drivers of biomass distribution. Main conclusions JeDI is a unique global dataset of GZ taxa which will provide a benchmark against which future observations can be compared and shifting baselines assessed. The presence of GZ throughout the world's oceans and across the complete global spectrum of environmental variables indicates that evolution has delivered a range of species able to adapt to all available ecological niches.

Data prediction and imputation are important parts of marine animal movement trajectory analysis as they can help researchers understand animal movement patterns and address missing data issues. Compared with traditional methods, deep learning methods can usually provide enhanced pattern extraction capabilities, but their applications in marine data analysis are still limited. In this research, we propose a composite deep learning model to improve the accuracy of marine animal trajectory prediction and imputation. The model extracts patterns from the trajectories with an encoder network and reconstructs the trajectories using these patterns with a decoder network. We use attention mechanisms to highlight certain extracted patterns as well for the decoder. We also feed these patterns into a second decoder for prediction and imputation. Therefore, our approach is a coupling of unsupervised learning with the encoder and the first decoder and supervised learning with the encoder and the second decoder. Experimental results demonstrate that our approach can reduce errors by at least 10% on average comparing with other methods.

The shoot demography and rhizome growth of Syringodium filiforme Kutz. and Halodule wrightii Aschers. were studied, based on plant dating techniques, to account for their role as pioneer in the succession sequence of Canbbean seagrasses. Results demonstrated that these species are able to develop dense meadows, supporting biomasses in excess of 500 g DW m They produced more than 2000 g DW m-2 yr-' due to their high leaf (5.0 to 8 5 yr.') and rhizome (2 0 to 3.3 yr') turnover. Rhizome growth and branch~ng rates were very high, allowing these seagrasses to rapidly occupy the space they colonise. The rapid rhizome turnover involved, however, a high shoot mortality rate and low 11fe expectancy (average shoot life expectancy 100 to 180 d). This implies that, while these pioneer species are able to rapidly occupy the space they colonise, their established shoots cannot occupy that space for a s long a s the more longlived species Thalassia testudinum. We suggest, therefore. that the role of seagrass species a s pioneer or climax species is independent of their capacity to support dense, productive populations, and is closely related to shoot longevity and rhizome turnover.

Understanding the consequences of rising CO 2 and warming on marine ecosystems is a pressing issue in ecology. Manipulative experiments that assess responses of biota to future ocean warming and acidification conditions form a necessary basis for expectations on how marine taxa may respond. Although designing experiments in the context of local variability is most appropriate, local temperature and CO 2 characteristics are often unknown as such measures necessitate significant resources, and even less is known about local future scenarios. To help address these issues, we summarize current uncertainties in CO 2 emission trajectories and climate sensitivity, examine region-specific changes in the ocean, and present a straightforward global framework to guide experimental designs. We advocate for the inclusion of multiple plausible future scenarios of predicted levels of ocean warming and acidification in forthcoming experimental research. Growing a robust experimental base is crucial to understanding the prospect form and function of marine ecosystems in the Anthropocene.

We measured net planktonic community production (NCP), community respiration (CR), and gross primary production (GPP) in September, February, and May in a subarctic Greenland fjord influenced by glacial meltwater and terrestrial runoff. Potential controls of pelagic carbon cycling, including the role of terrestrial carbon, were investigated by relating surface‐water partial pressure of CO 2 (P CO2 ), NCP, GPP, and CR to physicochemical conditions, chlorophyll a (Chl a) concentration, phytoplankton production, inventories of particulate (POC) and dissolved organic carbon (DOC) and vertical flux of POC. The planktonic community was net heterotrophic in the photic zone in September (NCP 5 ‒21 ± 45 mmol O 2 m ‒2 d ‒1 ) and February (NCP 5 ‒17 mmol O 2 m ‒2 d ‒1 ) but net autotrophic during a developing spring bloom in May (NCP 5 129 ± 102 mmol O 2 m ‒2 d ‒1 ). In September, higher temperatures, shorter day lengths, and lower Chl a concentrations compared with May caused increased rates of CR, lower GPP rates, and net heterotrophy in the photic zone. The GPP required to exceed CR and where NCP becomes positive was low (in May: 1.58 ± 0.48 µ mol O 2 L ‒1 d ‒1 and September: 3.06 ± 0.82 µ mol O 2 L ‒1 d ‒1 ) and in the range of open ocean values, indicating that allochtonous carbon did not stimulate CR. The P CO2 in the surface water was below atmospheric levels (September average 25.0 ± 0.71 Pa, February 35.4 ± 0.40 Pa, and May 19.8 ± 1.21 Pa), rendering the ecosystem a sink of atmospheric CO 2 . NCP was identified as an important driver of surface P CO2 , with high rates of autotrophy and vertical export of POC reducing surface P CO2 during summer. In winter, net heterotrophy added CO 2 to the water column, but this postive effect on P CO2 was balanced by simultaneous cooling of the water column, which decreased P CO2 because of increased solubility of CO 2 . High autochthonous production implies a relatively limited influence of allochthonous carbon on pelagic carbon balance and CO 2 dynamics in the fjord.

Photo 1: Typical examples of coral- (A) and algae-dominated (B) reef communities in the central Red Sea. The distance between the two sites is only 500 m. Changes from coral to algal dominance are observed globally, often as a result of local and/or global anthropogenic disturbances leading to the loss of live coral cover and the subsequent establishment of fast-growing algae. The consequences of these community changes for key ecosystem functions, such as primary productivity, calcification, organic matter, and nutrient recycling mediated by the underlying benthic communities are poorly understood. The alterations of these processes remain particularly uncertain with regard to the combined effects of environmental change. Photo credit: Florian Roth. Photo 2: Experiments were carried out at Abu Shosha reef located in the central Red Sea on the west coast of Saudi Arabia. The reef is characterized by a heterogeneous mosaic of patches of coral- and algae-dominated communities. Thus, this site allowed for the quantification of the functionality of both communities under identical environmental conditions. The detailed composition of benthic communities used for this experiment was assessed multiple times during the study period by benthic surveys and modern photogrammetry tools to account for the reef's structural complexity. Photo credit: Florian Roth. Photo 3: We used in situ incubations of natural coral- and algae-dominated reef communities to measure fluxes of oxygen, dissolved inorganic carbon, total alkalinity, dissolved organic carbon, and dissolved inorganic nitrogen. This non-invasive approach provides reproducible measurements of biogeochemical processes of structurally complex benthic communities. Thereby, it also accounts for the components of the carbon and nitrogen pool that are remineralized by microbial communities or cryptic fauna within the reef matrix. Photo credit: Holger Anlauf. Photo 4: A total of 2520 syringes with water drawn from the incubations chambers were collected to monitor changes in water chemistry and biological variables during the experiments; (A) a researcher collecting water samples from an algae-dominated reef community; (B) custom-made syringe-holders were used to stop the syringes from floating away; and (C) on the boat, water samples were filtered and/or processed directly for the highest quality in water chemistry measurements in the laboratory later on. Photo credit: (A) Holger Anlauf; (B) Florian Roth; (C) Luis Silva. These photographs illustrate the article “High summer temperatures amplify functional differences between coral- and algae-dominated reef communities” by Florian Roth, Nils Rädecker, Susana Carvalho, Carlos M. Duarte, Vincent Saderne, Andrea Anton, Luis Silva, Maria Ll. Calleja, Xosé Anxelu G. Morán, Christian R. Voolstra, Benjamin Kürten, Burton H. Jones, and Christian Wild published in Ecology. https://doi.org/10.1002/ecy.3226.

Animal-attached devices have transformed our understanding of vertebrate ecology. To minimize any associated harm, researchers have long advocated that tag masses should not exceed 3% of carrier body mass. However, this ignores tag forces resulting from animal movement. Using data from collar-attached accelerometers on 10 diverse free-ranging terrestrial species from koalas to cheetahs, we detail a tag-based acceleration method to clarify acceptable tag mass limits. We quantify animal athleticism in terms of fractions of animal movement time devoted to different collar-recorded accelerations and convert those accelerations to forces (acceleration × tag mass) to allow derivation of any defined force limits for specified fractions of any animal's active time. Specifying that tags should exert forces that are less than 3% of the gravitational force exerted on the animal's body for 95% of the time led to corrected tag masses that should constitute between 1.6% and 2.98% of carrier mass, depending on athleticism. Strikingly, in four carnivore species encompassing two orders of magnitude in mass (ca 2-200 kg), forces exerted by '3%' tags were equivalent to 4-19% of carrier body mass during moving, with a maximum of 54% in a hunting cheetah. This fundamentally changes how acceptable tag mass limits should be determined by ethics bodies, irrespective of the force and time limits specified.