Moored Observations of Currents and Water Mass Properties between Talaud and Halmahera Islands at the Entrance of the Indonesian Seas

The currents and water mass properties at the Pacific entrance of the Indonesian seas are studied using measurements of three subsurface moorings deployed between the Talaud and Halmahera Islands. The moored current meter data show northeastward mean currents toward the Pacific Ocean in the upper 400 m during the nearly 2-yr mooring period, with the maximum velocity in the northern part of the channel. The mean transport between 60- and 300-m depths is estimated to be 10.1–13.2 Sv (1 Sv ≡ 106 m3 s−1) during 2016–17, when all three moorings have measurements. The variability of the along-channel velocity is dominated by low-frequency signals (periods > 150 days), with northeastward variations in boreal winter and southwestward variations in summer in the superposition of the annual and semiannual harmonics. The current variations evidence the seasonal movement of the Mindanao Current retroflection, which is supported by satellite sea level and ocean color data, showing a cyclonic intrusion into the northern Maluku Sea in boreal winter whereas a leaping path occurs north of the Talaud Islands in summer. During Apri–July, the moored CTDs near 200 m show southwestward currents carrying the salty South Pacific Tropical Water into the Maluku Sea.

A southward range extension of a wreckfish, Stereolepis doederleini (Actinopterygii: Acropomatiformes: Polyprionidae), to tropical water off eastern Taiwan

A wreckfish, Stereolepis doederleini Lindberg et Krasyukova, 1969, inhabits typical cold or temperate waters and was previously known from Great Bay (Sea of Japan), Korea, south to Kyuhu-Palau Ridge of Japan. In the present report, a specimen of this fish was collected from southeastern Taiwan representing the southernmost distribution of the cold-water genus Stereolepis in the Northern Hemisphere, with a southward extension into the tropical region. It is also the first record of a member of the family Polyprionidae from Taiwan. Here we document the species found in Taiwan, with a detailed description of the specimen.

On the Advection of Upwelled Water on the Western Yucatan Shelf

Upwelling events over the Yucatan Shelf are an important physical phenomenon to the region. They typically happen during spring and summer and had been studied for some time with a primary focus on the development on the eastern side of the shelf and later transport to the central part of the Peninsula. There has been very little effort looking at the impact of upwelling on the western shelf, on the Campeche side. Using a combination of observations and modeling from 2018, we show evidence for the first time, of the presence of upwelled water on the western side. Particle tracking, integrated back-in-time, was used to identify the origin of the upwelled water. Our results show that Caribbean Subtropical Underwater was brought from the northeast shelf, over 500 km away from the study area, by advection. This water took over a month (40 days) to arrive at the study region, traveling along-shelf with an average velocity of 14.5 cm/s. In the nearshore waters off the Campeche Coast, Caribbean Tropical Water was underlain by upwelling Caribbean Subtropical Underwater. Monthly averaged sea surface temperature (SST) anomalies from a 39-year time series suggest that upwelled water off Campeche is a regular phenomenon during summer, while the recurrence of westward advection is supported by climatological Lagrangian Coherent Structures. More studies are needed to explore the frequency of occurrence and impact of these events on the western shelf.

The first floristic study of freshwater dinoflagellates (Dinophyceae) in Colombia

The first comprehensive study of dinoflagellate flora and their related environmental variables in reservoirs, swamps, and an insular lake of Colombia is presented. Fourteen Colombian water bodies were assessed. In each, water temperature, electric conductivity, oxygen saturation, turbidity, and apparent color were the physical and chemical variables measured. Twelve dinoflagellate taxa were recorded, indicating a considerable richness compared to similar surveys. Ensembles recovered showed a spatial structuration mediated by the type of the water bodies (reservoirs and swamps); environmental variables and species richness explained equally the differences among the water bodies. The dinoflagellate flora showed altitudinal segregation, with intermediate altitude systems displaying the highest richness values. A brief discussion about the geographical distribution of the species collected is offered. The study contributes to the knowledge of the ecological aspects of dinoflagellate flora and outlines preliminary biodiversity tendencies of ensembles in tropical water systems.

Abundance and Microbial Diversity from Surface to Deep Water Layers Over the Rio Grande Rise, South Atlantic

Marine microbes control the flux of matter and energy essential for life in the oceans. Until now, the distribution and diversity of planktonic microorganisms above Fe-Mn crusts has received relatively little attention. Future mining\dredging of these minerals is predicted to affect microbial diversity and functioning in the deep sea. Here, we studied the ecology of planktonic microbes among pelagic environments of an Fe-Mn deposit region, at Rio Grande Rise, Southwestern Atlantic Ocean. We investigated microbial community composition using high-throughput sequencing of 16S rRNA genes and their abundance estimated by flow cytometry. Our results showed that the majority of picoplanktonic was found in epi- and mesopelagic waters, corresponding to the Tropical Water and South Atlantic Central Water. Bacterial and archaeal groups related to phototrophy, heterotrophy and chemosynthesis, such as Synechococcales, Sar11 (Proteobacteria) and Nitrosopumilales (Thaumarchaeota) were the main representatives of the pelagic microbial community. Additionally, we detected abundant assemblages involved in biodegradation of marine organic matter and iron oxidation at deep waters, i.e., Pseudoalteromonas and Alteromonas. No differences were observed in microbial community alpha diversity. However, we detected differences in community structure between water masses, suggesting that changes in an environmental setting (i.e. nutrient availability or circulation) play a significant role in structuring the pelagic zones, also affecting the meso- and bathypelagic microbiome.HighlightsRio Grande Rise pelagic microbiomePicoplankton carbon biomass partitioning through pelagic zonesUnique SAR11 Clade I oligotype in the shallowest Tropical WaterHigher number of shared oligotypes between deepest water massesNitrogen, carbon and sulfur may be important contributors for the pelagic microbiome

Reproduction of tropical water lilies

The study of coastal and aquatic tropical flora as part of the conservation of world biodiversity is the main purpose of research in botanical gardens. Conservation of plant collections involves a continuous process of plant reproduction. This means searching for ways of reproduction that are most effective for a particular group of plants and optimal timing of obtaining adult specimens. Generally accepted methods for seed (T. A. Rabotnov) and vegetative reproduction were used; for Nymphaea x daubeniana (viviparous water lily) was used the Sean Stevenson method. During 2017-2020 in the Stavropol Botanical Garden was conducted an experiment to study the reproduction of tropical water lilies in protected ground conditions. An artificial pond with a water mirror area of 85 m2 is located in a greenhouse, heated from October to April. Cross-pollination occurs during the mass flowering period (June-July, with illumination up to 93.5•103 kilolux), seed maturation occurs within 58±4 days, and seedlings bloom in 7-8 months. The moderate correlation was established between the soil composition and the intensity of flowering (p < 0.4) and the formation of nodules (p < 0.4). The absence or short flowering of water lily varieties and the mass of nodules (150-300 g) contributes to the formation of more planting material (up to 12 or more pieces). The vegetation period for 99% of the studied plants is 1478±26 days, for the species Nymphaea gigantea it is 887±15 days. Regardless of the species and variety of tropical water lilies, reproduction by daughter nodules formed at the base of the main tuber occurs throughout the growing season.

Increasing tropical water control on interannual CO2 growth rate over the past decades

&lt;p&gt;Terrestrial climate-carbon feedbacks are the leading-order uncertainties in climate projections, hindering&amp;#160;the full assessment of climate mitigation scenarios. Since year-to-year variations of atmospheric carbon dioxide growth rate (CGR) are mostly driven by fluctuations of tropical land carbon fluxes, it provides a &amp;#8220;natural experiment&amp;#8221; to explore the climate drivers of terrestrial carbon cycle. Recently, direct observations of terrestrial water storage confirmed the tight coupling between&amp;#160;the&amp;#160;water and carbon cycles, in addition to the well-documented temperature effects. Here we show that the strength of this relationship between CGR and&amp;#160;the interannual variability of&amp;#160;tropical water has increased substantially&amp;#160;from 1960 to 2018&amp;#160;and has even recently&amp;#160;become stronger than CGR-temperature correlations. We find&amp;#160;that&amp;#160;this increment may be relevant to local drying trends in a warming climate and&amp;#160;that&amp;#160;above-ground&amp;#160;carbon uptake might be a critical underlying ecological process. We also demonstrate that most state-of-the-art&amp;#160;Earth System&amp;#160;models and land surface models do not capture this increasing carbon-water coupling over time. Our results suggest that tropical water availability could increasingly dominates the interannual variability of&amp;#160;the&amp;#160;terrestrial carbon cycle&amp;#160;in the future and&amp;#160;that current&amp;#160;models may not be able to capture this feature.&lt;/p&gt;