Volume 61, Issue 6

Marine biodiversity and ecosystem functioning – including seaweed communities – in the territorial waters of the UK and its Overseas Territories are facing unprecedented pressures. Key stressors are changes in ecosystem functioning due to biodiversity loss caused by ocean warming (species replacement and migration, e.g. affecting kelp forests), sea level rise (e.g. loss of habitats including salt marshes), plastic pollution (e.g. entanglement and ingestion), alien species with increasing numbers of alien seaweeds (e.g. outcompeting native species and parasite transmission), overexploitation (e.g. loss of energy supply further up the food web), habitat destruction (e.g. loss of nursery areas for commercially important species) and ocean acidification (e.g. skeletal weakening of ecosystem engineers including coralline algal beds). These stressors are currently affecting biodiversity, and their impact can be projected for the future. All stressors may act alone or in synergy. Marine biodiversity provides crucial goods and services. Climate change and biodiversity loss pose new challenges for legislation. In particular, there are implications of climate change for the designation and management of Marine Protected Areas and natural carbon storage by marine systems to help control the global climate system. The UK currently has legal obligations to protect biodiversity under international and European law.

The seagrass Thalassodendron ciliatum (Cymodoceaceae) is uncommon in Palau, Micronesia, but remnant beds occur in an area of less than 1 km 2 on the northern tip of Velasco Reef, a sunken atoll, plus small areas on its western rim. The ridges are lengthy, consisting of rhizome mat and seagrass up to 1 m high, and 4–8 m wide forming curving elongate shapes (arcs, concentric curves, circles, patches). Most occur on a gently sloping limestone bottom 22–27 m deep, with some as shallow as 15 m on the Western Rim, and ridges sit directly on top of the limestone pavement, with only the weight of mat and its incorporated rock materials holding them in place. Photographic monitoring over time has indicated they are actively eroding on their edges, but the passage of Super Typhoon Haiyan in 2013 caused much greater damage to the beds. Small patches occur in shallow water on the east side of Babeldaob Island slightly behind the fringing reef crest and have not changed significantly over recent decades.

Seagrass meadows are highly productive habitats that support commercially and ecologically important fishes and invertebrates. However, evidence of fish-habitat relationships are seldom drawn from forereef seagrass meadows that are structurally simple in terms of species richness and relative size and, consequently, their role as habitats is unclear. In this study, fish-habitat relationships were examined in such meadows in the forereef seagrasses of Tinggi Island and Babi Besar Island, Malaysia, by documenting habitat complexity attributes (canopy height, shoot density and percent cover), distance to adjacent coral reefs, and water depth within 2×2 m quadrats. Fish assemblages were recorded using the Remote Underwater Video Station method. A total of 1166 individuals from 86 taxa were found and enumerated. This study showed that (1) fish density and species richness were significantly associated with seagrass percent cover alone; (2) commercially important carnivores formed the majority of the fish populations in the meadows, and (3) fish density and species richness were positively correlated with distance to the nearest adjacent coral reef, indicating the need to account for the effects of neighboring habitats in studies of this nature. Thus, structurally simple seagrass meadows are still important fish habitats, especially as feeding grounds for commercially significant carnivores.

The increasing incidence of eutrophication has potentially detrimental socio-economic and ecological consequences. This study aimed to elucidate the temporal dynamics of algal communities in response to increasing initial concentrations of inorganic nitrogen (particularly nitrate) – central components of eutrophication. A contained microcosm experiment was designed to mimic the conditions of shallow oligotrophic estuaries with high water residence times. Phytoplankton, microphytobenthos and filamentous algal community dynamics were observed over a 28-day experimental period under different nitrate regimes. Key observations included (1) accelerated filamentous algal growth, (2) rapid loss of phytoplankton biomass and abundance, and (3) reduced benthic diatom species diversity and richness in the “1.0 μ m Nitrate Addition” treatment. Additionally, model results highlighted the positive relationship between filamentous algal growth and increased water temperature. From a global change perspective, the decline in microalgal abundance and diversity at the onset of filamentous algal growth in warm, N-enriched environments suggests a potential uncoupling of trophic pathways. However, the “Control” and “0.5 μ m Nitrate Addition” treatments were similar in their algal responses, highlighting the ability of ecosystems to absorb small disturbances. Thus, it is critical that estuarine resilience is preserved to ensure continued provision of invaluable ecosystem services.

In the historical Grunow collection in Vienna, a piece of a broken slide covered with mica contained diatom material from Porto Subzanski, a coastal environment in Croatia. This material was examined in scanning electron microscopy. Several poorly documented or improperly assigned taxa within the Achnanthales, namely in Amphicocconeis and Cocconeis , were re-examined. A new combination of Amphicocconeis and a new species of Cocconeis are proposed. The new species, Cocconeis subzanskiensis , is closely related to Cocconeis placentula , except for the lack of a characteristic hyaline sub-marginal rim on the raphe valve, and is compared with other marine taxa pertaining to the same group. Recently described in tropical environments, Cocconeis coronatoides has been found in the Grunow material.

The hypersaline Inland Sea in Qatar constitutes a unique ecosystem characterized by salinities up to saturation, extreme temperature fluctuations, and limited rainfall. To reveal the fungal diversity of this environment, we isolated fungi from water samples collected at the Inland Sea. Taxonomic identification of the isolates was done via DNA barcoding of the ITS1 and ITS2 ribosomal DNA (rDNA) domains and the D1/D2 domains of the nuclear large subunit rDNA. Additional genes, including glyceraldehyde-3-phosphate dehydrogenase ( gapdh ) and translation elongation factor 1-alpha ( tef1 ), were included for isolates of Alternaria , actin (Act) for Cladosporium , part of the beta-tubulin ( BenA ) and calmodulin ( CaM ) genes for Aspergillus and Penicillium . In total, 159 fungal isolates, including 85 Ascomycota and 74 Basidiomycota, were obtained from the water samples collected during four samplings in the winter and summer seasons. About 14% (22/159) of the strains, presumably novel species, were preliminarily identified to the genus level. This is the first report highlighting the diversity of fungi from the hypersaline Inland Sea in Qatar.